Team3S: 3000GT & Stealth Thursday, February 13 2003 Volume
02 : Number 080
----------------------------------------------------------------------
Date: Wed, 12 Feb 2003 14:37:49 -0800
From: "Damon Rachell" <
DamonR@mefas.com>
Subject: Team3S: Re:
offlist...
All this talk makes me thing that porting is far more important than
polishing heads. I'll have to check with some friends who professionally
port and polish. Maybe this is new info and should replace the old school
opinions! I'm guessing flow testing is the only way to really tell.
Is it possible to test flow velocity as well as volume on a flow
bench?
> Interesting point. Sometime back was watching special
> on
the America Cup sailboat races. They found that
> putting small
ridges on the hull made the boat faster
> than the hull was completely
smooth. I think that a
> small amount of water would be trapped,
then it was
> water on water instead of hull on water...
>
>
I'd imagine same is true for the intake charge.
>
> Glenn
------------------------------
Date: Wed, 12 Feb 2003 14:53:32 -0800
From: "Gross, Erik" <
erik.gross@intel.com>
Subject:
Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
Ok, I don't get it. Really. I can come up with some "grasping
at straws" theoretical BS that might explain this, but it definitely wasn't what
I was expecting...
Last night, I finally got around to putting my stock (OEM, not high-flow)
catalytic converter back on my car instead of a 3" test pipe. The main
reason I did this was because of the noise issue. After putting on an
aftermarket downpipe and testpipe, my car was LOUD when above 2000RPM or with
any kind of throttle over 25%. Many NWS3 guys can attest to that, as well
as my neighbors who probably hate me. The only other reason for putting
the catalytic converter back on might be some tiny shred of extremely atrophied
environmental conscientiousness, but I digress... I lived with the noise
for several months and finally the annoyance provided enough motivation to do
something about it.
Needless to say, I was expecting to be making a tradeoff of power/boost vs.
noise. Less noise and slightly less power/boost (all else equal).
That is not the case.
I now hold more boost to redline (0.66kg vs. a previous rock-solid,
repeatable 0.65-0.64kg). I know that's not much of an increase, but *it's
not a decrease* like I expected.
I also have about 50% of the boost spiking I used to have. I have a
non-learning boost controller with the same settings (ALL I changed was swapping
the testpipe for the catalytic converter). I used to have spikes to
1.03-1.05kg and hold 0.80 at 2000RPM in 6th (good representation of steady-state
boost). Now I still hold that much in 6th at 2000RPM and I only get spikes
to 0.91kg if I pre-spool the turbos and then goose the crap out of it.
Most of the time I get spikes to only 0.87kg or so.
>From the seat of the pants, I don't think I've lost any substantial
boost in the mid-RPM range, and I can definitely feel the much lower boost
spiking. When abruptly floored, the car used to hit really hard and then relent
a bit as the tach climbed. Now it hits and doesn't appreciably lessen, all
the way to redline. I'll get some dyno charts soon to see if the HP curve
drops off much in the top end. I'm guessing not.
As for the noise, the car is MUCH nicer sounding now. Not harsh and
raspy (like a muscle car), but a nice smooth growl at WOT and almost silent at
warm idle. That was my desired result, but I certainly didn't expect the
change in boost behavior.
As for an explanation, the only thing I can come up with is that somehow
the catalytic converter smoothes out the exhaust flow and the smoother flow
helps with boost spiking and allows for slightly higher boost in the top end,
even though the catalytic converter is a flow restriction. But that seems
fishy to me.
Comments? Explanations?
- --Erik
'95 VR-4 (relevant stock/aftermarket items)
Stock Cat-back
Exhaust
Stock Main Catalytic Converter
Stock Fuel, except for FP Relay
Addition
Stock Ignition, except for Magnacor wires
Stock Mitsu TD04-9b
Turbos
Tyspeed EG-Spec Downpipe
Improved Rear Precat
Housing
K&N
GReddy TypeS BPV
Aquamist 2s Water/Alky
Injection
Blitz DSBC r:50 g:3
Gauges for Boost x 3, FP, OP, OT, WT,
EGTF, EGTR, A/F
F, A/F R
------------------------------
Date: Wed, 12 Feb 2003 23:06:50 -0000
From: "Jeff Lucius" <
jlucius@stealth316.com>
Subject:
Re: Team3S: Is it true cylinder #1 runs hotter?
I have not been following this thread closely, but it looks like somebody
thinks that unequal flow through the plenum and runners may put more air
into
one cylinder than another and thus tend to make that (those)
cylinder(s) run
leaner (assuming equal fuel distribution). If this is the
case, then how do
you account for the following.
In the DOHC 6G72, the intake valves are closed ~65% of the time (using
gross
duration of 251º) or not flowing much air ~71% of the time (using
~208º at
0.050" lift). This means air is basically just piling up (*not
flowing*) in
the manifold and runner in front of the valves (for one
cylinder), **just as
the fuel is**, at least 65% of the time (that would be
~39 seconds out of a
minute broken into RPM/2 pieces). So how does this
factor into all the flow
and flow distribution theories?
The PCV channel under the intake manifold connects all six ports. How does
this affect flow equalization?
------------------------------
Date: Thu, 13 Feb 2003 00:12:15 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
The main cat is not a restriction itself beside of the small in and out
diameter. It flows pretty well and I know several owners that removed the
pre-cats bit kept the main one. But of course this only belongs to low
rpm.
Your observation is correct. You have less spikes due to the fact that the
turbos are not spooling that quick anymore. Therefore you can see the main cat
as a part that adds backpressure. As you have removed the pre-cats it now has
become the first restriction in the path after the DP. There are no
pulse-smoothening parts before the main cat so it will do the job now. You are
absolutely right about the sound you have now. You may consider a high flow cat
too, nice flow together with smoothened gases and therefore lower noise.
Your amount of boost at the redline is really low. Is your boost controller
set up properly ?
Holding boost at 2000rpm is nothing to talk about. The airflow is just too
low to make a judgment. As previously said, it is not a big restriction, but the
higher the airflow (i.e. high boost and high rpm) the more it becomes one.
> I now hold more boost to redline (0.66kg vs. a previous rock-solid,
> repeatable 0.65-0.64kg). I know that's not much of an increase,
but
> *it's not a decrease* like I expected.
>
> I also have
about 50% of the boost spiking I used to have. I have a
>
non-learning boost controller with the same settings (ALL I changed
> was
swapping the testpipe for the catalytic converter). I used to
>
have spikes to 1.03-1.05kg and hold 0.80 at 2000RPM in 6th (good
>
representation of steady-state boost). Now I still hold that much in
> 6th at 2000RPM and I only get spikes to 0.91kg if I pre-spool the
> turbos and then goose the crap out of it. Most of the time I get
> spikes to only 0.87kg or so.
>
> From the seat of the
pants, I don't think I've lost any substantial
> boost in the mid-RPM
range, and I can definitely feel the much lower
> boost spiking. When
abruptly floored, the car used to hit really hard
> and then relent a bit
as the tach climbed. Now it hits and doesn't
> appreciably lessen,
all the way to redline. I'll get some dyno charts
> soon to see if
the HP curve drops off much in the top end. I'm
> guessing
not.
>
> As for the noise, the car is MUCH nicer sounding now.
Not harsh and
> raspy (like a muscle car), but a nice smooth growl at WOT
and almost
> silent at warm idle. That was my desired result, but I
certainly
> didn't expect the change in boost behavior.
>
>
As for an explanation, the only thing I can come up with is that
>
somehow the catalytic converter smoothes out the exhaust flow and the
>
smoother flow helps with boost spiking and allows for slightly higher
>
boost in the top end, even though the catalytic converter is a flow
>
restriction. But that seems fishy to me.
------------------------------
Date: Thu, 13 Feb 2003 00:15:16 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Is it true cylinder #1 runs hotter?
I already mentioned this Jeff, although I haven't used the figures
;-)
> The PCV channel under the intake manifold connects all six ports. How
> does this affect flow equalization?
IMHO, this channel is to equalize pressure and doesn't account to flow.
Also it is there to distribute the fumes of the PCV to all chambers.
------------------------------
Date: Wed, 12 Feb 2003 15:38:57 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Is it true cylinder #1 runs hotter?
> I have not been following this thread closely, but it looks
>
like somebody thinks that unequal flow through the plenum
> and runners
may put more air into one cylinder than another
> and thus tend to make
that (those) cylinder(s) run leaner
> (assuming equal fuel distribution).
Correct.
> If this is the case, then how do you account for the following.
I dunno. I'm just posing the question - I don't have the
answers. :) I read in what I consider to be an authoritative source
("Forced Induction Performance Tuning", A. Graham Bell) that an intake plenum
designed like ours will tend to result in more air to the cylinders furthest
from the throttle body. Bell states that you can counter this effect by
tapering the main plenum area, or by opening up the mouths of the runners closes
to the throttle.
The discussion so far on a DIY EFI list I subscribe to suggests that simply
flow testing the plenum won't give the full story. The pressure waves from
opening/closing valves make the problem much more complex.
None the less, it seems that there is some merit to this idea of unequal
air distribution. I trust the Bell book quite a bit, and I've seen
aftermarket plenums for other cars use this tapering strategy. What we
need to figure out is whether it'd be worth it for _us_ to undertake a plenum
redesign. :)
- - Brian
------------------------------
Date: Wed, 12 Feb 2003 15:45:14 -0800
From: "Gross, Erik" <
erik.gross@intel.com>
Subject: RE:
Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
> Your amount of boost at the redline is really low. Is your
>
boost controller set up properly ?
Yeah, I'm pretty sure. That number (0.65kg) is also consistent with a
friend's 94 VR-4 with similar modifications. He's running an AEM EMS
(with
datalogging) and has a manual boost controller. Thus his MBC
should not be restricting high-end boost at all - his high end boost should be
whatever the turbos are capable of, since the MBC would be closed at that point
and the wastegates would be seeing no pressure. My number is very
consistent with his graphs from the AEM. BTW, he's using the same GM 3-bar
MAP sensor for his AEM as I have installed for my WI system, and that's where
his data comes from. My boost data comes from 3 different boost gauges
(Boost Controller, Gauge, HUD - excessive, I know, I know...)
>
Holding boost at 2000rpm is nothing to talk about. The
> airflow is just
too low to make a judgment.
Around 2000RPM is where my boost settles off - that seems to be a good
place to look to me - it's relatively stable and I can watch/read it
easily. I maintain 0.80kg +/- 0.02kg from 2000RPM to as high as I care to
go in 6th gear, so I think it's a pretty good indication for what the turbos are
capable of producing at a given boost controller solenoid duty cycle.
- --Erik
------------------------------
Date: Wed, 12 Feb 2003 15:48:06 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
> Your amount of boost at the redline is really low. Is your
>
boost controller
> set up properly ?
I see about the same amount of boost to redline (9.5 PSI, or so) on the
datalogs from my AEM, running very similar exhaust modifications.
- - Brian
------------------------------
>friend's 94 VR-4 with similar modifications. He's running an AEM
EMS
>(with
>datalogging) and has a manual boost controller.
A 94 with data logging? Tell me more.
I didn't know a 94 could connect
to anything.
Can it see the knock sensor and all that good stuff?
Rich/slow old poop/94 VR4
------------------------------
Date: Wed, 12 Feb 2003 15:59:48 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Data logger for 94
The AEM EMS totally replaces the stock ECU, so I can twiddle with and log
anything I feel like. Knock sensor and knock control included.
- - Brian
> -----Original Message-----
> From:
merritt@cedar-rapids.net
[mailto:merritt@cedar-rapids.net]
> Sent: Wednesday, February 12, 2003
3:53 PM
>
> >friend's 94 VR-4 with similar modifications.
He's running
> an AEM EMS (with datalogging) and has a manual boost
controller.
>
> A 94 with data logging? Tell me more.
> I
didn't know a 94 could connect to anything.
> Can it see the knock sensor
and all that good stuff?
------------------------------
At 03:59 PM 2/12/03 -0800, Geddes, Brian J wrote:
>The AEM EMS
totally replaces the stock ECU, so I can twiddle with and
>log anything I
feel like. Knock sensor and knock control included.
What does one of those puppies cost and where do you get it? Does it help
performance, or just log data?
------------------------------
Date: Thu, 13 Feb 2003 01:08:04 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Data logger for 94
Rich, the AEM EMS has nothing to do with the logging we do on the stock
ECU. Go to their site to learn about this standalone CPU, it's great for highly
modified cars !
> >friend's 94 VR-4 with similar modifications. He's running an
AEM
> EMS (with datalogging) and has a manual boost
controller.
>
> A 94 with data logging? Tell me more.
> I
didn't know a 94 could connect to anything.
> Can it see the knock sensor
and all that good stuff?
>
> Rich/slow old poop/94 VR4
------------------------------
Date: Thu, 13 Feb 2003 01:20:41 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
> Yeah, I'm pretty sure. That number (0.65kg) is also consistent
with a
> friend's 94 VR-4 with similar modifications. He's running
an AEM EMS
> (with datalogging) and has a manual boost controller.
Thus his MBC
> should not be restricting high-end boost at all - his high
end boost
> should be whatever the turbos are capable of, since the MBC
would be
> closed at that point and the wastegates would be seeing no
pressure.
We shift off the main topic but it seems that there is a misunderstanding
here.
The turbos are able to deliver that high amount of boost that your engine
can be killed. You can easily see 1.3 bars of boost around 4000 rpm ! So what
you are saying is not correct as the boost controller regulates the boost
according to the set parameters. But on a certain point of air flow the
compressors cannot deliver the desired air flow to maintain the boost. This
starts at about 4800rpm where pressure then falls off to about 0.8 bars. The
more the engine may be able to flow the sooner the 9b are running out of
steam.
An AEM EMS and an MBC ?... sounds not like a good combination.
> with his graphs from the AEM. BTW, he's using the same GM 3-bar
MAP
> sensor for his AEM as I have installed for my WI system, and that's
> where his data comes from. My boost data comes from 3 different
boost
> gauges (Boost Controller, Gauge, HUD - excessive, I know,
I
> know...)
... and I hope not only from one small nipple in the intake plenum !!
> Around 2000RPM is where my boost settles off - that seems to be a good
> place to look to me - it's relatively stable and I can watch/read it
> easily. I maintain 0.80kg +/- 0.02kg from 2000RPM to as high as I
> care to go in 6th gear, so I think it's a pretty good indication for
> what the turbos are capable of producing at a given boost controller
> solenoid duty cycle.
This just sounds odd to me, doesn't make sense at all. Of course pressure
will be stable unless your boost controller is not set up correctly. Of course
the controller regulates to what it is set to even with rising rpms. So it
doesn't say anything unless you want to see where the turbos are dropping off.
But they will not when the controller is set at 0.8 bars as then boost always
stays the same.
If you set the controller to reach 1,05 bars, it should hold boost to about
4800 to 5000 and then come down to about 0.8 - 0.9 bars max depending on the
flow modifications. Of course this only belongs to a 5 or 6th gear test like it
is done on the dyno and the boost drop can be watched.
But you forget many other factors like the 9b running out of the efficiency
fields and producing a very high intake temperature. Of course you take care of
this with the water injection. But to be honest, what is the WI for when you
only run 0,8 bars of boost with a 6500 rpm boost of 0,6 ? This just sounds odd
to me.
------------------------------
Date: Thu, 13 Feb 2003 01:35:01 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
Brian, you may think about what the AEM is able to do to your car with a
MBC set to 9,5 psi. Here's a dyno-plot of my car with the 13g (that do not
flow much more but provide a better efficiency island) :
The run was done in 4th gear under full load. You can see that boost is
reaching 1 bar at 3000rpm and slightly climbs with the controller specific
ripples up to 1.03 bars. At 4600 the boost starts to descend and at 6000rpm it
had 0.95 bars of boost.
The only mods were 13g (stock in Europe), MSD DIS-4, ARC2-GP, 720cc, Apexi
Air filter, Denso fuel pump and a Greddy BOV. The ERL WIS prevented the system
from knocking (well I saw knock due to the bad cooling on the dyno). No exhaust
mods at all.
So I'd say that the AEM and boost controller do not act properly together
as you should see at least 0.85 bars with the 9b at 6500 ! If not then you may
consider to retune the AEM properly and getting a good boost controller (or use
the AEM built-in function). That must help or your timing gets to heavily
retarded that it regulates it's boost down by itself due to knock !!
- ----- Original Message -----
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Sent:
Thursday, February 13, 2003 12:48 AM
> > Your amount of boost at the redline is really low. Is your boost
> > controller set up properly ?
>
> I see about the same
amount of boost to redline (9.5 PSI, or so) on
> the
datalogs from my
AEM, running very similar exhaust modifications.
>
> - Brian
------------------------------
Date: Wed, 12 Feb 2003 16:28:10 -0800
From: "fastmax" <
fastmax@cox.net>
Subject: Re: Team3S:
Data logger for 94
It's not for the amateur --- you need to know about fuel maps, manifold
absolute pressure, stoich, open and closed loop etc. etc. You'd have to learn
more than you ever wanted to know about internal combustion engines.
Jim Berry
====================================================
> At 03:59 PM 2/12/03 -0800, Geddes, Brian J wrote:
> >The AEM
EMS totally replaces the stock ECU, so I can
> >twiddle with and log
anything I feel like. Knock sensor
> >and knock control
included.
>
> What does one of those puppies cost and where do you
get it? Does it
> help performance, or just log data?
>
>
Rich/slow old poop/94 VR4
------------------------------
Date: Thu, 13 Feb 2003 01:38:56 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: Data logger for 94
I highly agree with Jim
Whenever I have time and money I will install it in one of my cars too...
although I already have the advantage of having programmed the EPROMs in an ECU
by myself to change the fuel and ignition maps. But I also will start slowly
;-))
> It's not for the amateur --- you need to know about fuel maps,
> manifold absolute pressure, stoich, open and closed loop etc. etc.
> You'd have to learn more than you ever wanted to know about internal
> combustion
engines.
>
> Jim
Berry
------------------------------
At 04:28 PM 2/12/03 -0800, fastmax wrote:
>It's not for the amateur
--- you need to know about fuel maps, manifold
>absolute pressure,
stoich, open and closed loop etc. etc. You'd have to
>learn more than you
ever wanted to know about internal combustion
>engines.
>
Well,
boo poopie.
I just wanted to find a datalogger for a 94 VR4 so I can monitor
knock and other critical stuff and don't blow me engine up at 15 psi. Guess it's
back to 110 octane race gas. It's my only insurance at the moment.
Rich/94 VR4>
------------------------------
Date: Wed, 12 Feb 2003 16:51:33 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
Roger -
In regards to redline boost, there are two factors that determine how much
boost the car can hold to redline. First, the output of the turbos.
Secondly, the air consumption of the engine.
In the example you presented, BOTH of these factors are different from the
setup Erik and I have. The 9b turbos are grossly undersized, and simply
run out of steam in the upper revs. The compressor flow maps on Jeff's
site project a maximum boost of right around 10 PSI at redline, and my real
world experience corresponds. Those 13g's you get in Europe are capable of
holding a great deal more boost to redline, because they simply push more
air.
Secondly, opening up the exhaust will increase the volumetric efficiency of
the engine, allowing it to consume greater amounts of air. Most people
think that putting on a downpipe will allow them to run more boost to
redline. I don't think this is true. Exhaust modifications (downpipe
and precats especially) will allow the engine to ingest more air (greater
VE). If the turbo is already at the limit of its output with stock
exhaust, I'd expect to actually see LESS boost to redline after exhaust
modifications. The turbos are putting out the same amount of air, but
because the engine is more efficient, and taking in more air per rev, we'll
actually see a LOWER boost level.
Hmm...I've actually never thought about it that way before. Erik, by
the way, that may be the answer to your question about the higher boost with the
cat on. :)
As for the AEM, I think it's working just fine. In fact, my power
calculations have me making about 300 HP at the wheels at 10-11 pounds of
boost. Pretty good in my book. :) There's nothing wrong with a
ball-and-spring style MBC; they hold remarkably stable boost levels. That
being said, I've since started using the AEM's boost control functions, because
it's easier to quickly change the boost level.
- - Brian
------------------------------
Date: Wed, 12 Feb 2003 16:44:44 -0800
From: "fastmax" <
fastmax@cox.net>
Subject: Team3S: dust
shields
I need a set of front dust shields for a 2nd gen car. I'm playing with some
cooling ducts and managed to through out my shields that I removed a couple of
years ago. Condition isn't important
although price is --- cheap is good,
free is better.
Jim Berry
------------------------------
Date: Wed, 12 Feb 2003 16:54:01 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Data logger for 94
I totally agree. In fact, I've spent a significant amount of time
making posts on 3SI warning people about the complications of the AEM EMS.
If you're interested, do a search for posts with containing "AEM", by my 3SI
user name (FWombat).
The AEM gives you total control. Total. As with anything else
in life, power can be good or bad, depending on what you do with it.
- - Brian
> -----Original Message-----
> From: fastmax
[mailto:fastmax@cox.net]
> Sent: Wednesday, February 12, 2003 4:28
PM
>
> It's not for the amateur --- you need to know about
fuel
> maps, manifold absolute pressure, stoich, open and closed
>
loop etc. etc. You'd have to learn more than you ever
> wanted to know
about internal combustion engines.
------------------------------
Date: Wed, 12 Feb 2003 17:00:54 -0800
From: "Gross, Erik" <
erik.gross@intel.com>
Subject: RE:
Team3S: Cat Instead Of Testpipe Yields More Boost, Less Spiking
Roger, first off, lemme say that I have a pretty solid understanding of
compressor flow maps, engine volumetric efficiency, boost controllers, and a lot
of other stuff. However, certainly there is a lot that I don't know. Let
me explain some of my comments a little more clearly because I think I didn't
get a couple things across well, based on the explanations in your
response.
One area of uncertainty I have is *exactly* what the Gain and Ratio
settings on the Blitz DSBC actually do. There is no "set the boost
controller for 0.95 bar" setting on this controller. You get to control
this thing they call "Gain" and this thing they call "Ratio". I've never
heard a good explanation of what exactly those things adjust. >From
what I've read and from personal experience, it seems that the "Ratio" setting
essentially sets the target duty cycle for the solenoids (regulating how much
pressure they will allow to reach the wastegates) and the "Gain" controls
spiking somehow
- - I'm guessing by temporarily using a higher solenoid duty
cycle based on the rate that boost is rising.
> The turbos are able to deliver that high amount of boost that
>
your engine can be killed. You can easily see 1.3 bars of
> boost around
4000 rpm ! So what you are saying is not correct
> as the boost controller
regulates the boost according to
> the set parameters.
Yeah, I know at lower flow rates, the 9b turbos can produce quite a bit of
boost. I've seen it in person on a car with 9b turbos, propane injection,
and all-but-disconnected wastegate pressure lines. Pulled like no 9B car
I've ever ridden in. The issue I have is what exactly my boost controller
is doing. I can't see that the Blitz DSBC has some target pressure that it
tries to achieve, because as ambient air density changes (altitude or temp), the
boost pressure achieved fluctuates, sometimes as much as 0.1bar.
> An AEM EMS and an MBC ?... sounds not like a good combination.
Temporary until his GM boost solenoid arrived on the UPS
truck.
> ... and I hope not only from one small nipple
in
> the intake plenum !!
No, I have 4 boost sensors in my engine bay, all run off of a 3/8" hose
plumbed into the plenum. The FPR line is completely separate.
> > Around 2000RPM is where my boost settles off - that
seems
> > to be a good place to look to me
>
> This just
sounds odd to me, doesn't make sense at all. Of
> course pressure will be
stable unless your boost controller
> is not set up correctly. Of course
the controller regulates
> to what it is set to even with rising
rpms.
With rising RPMs, yes, but if you change something on the car that affects
the volumetric efficiency of the engine or the flow efficiency of the turbos,
the Blitz DSBC does not produce the same peak or sustained boost. For example,
when going from a stock downpipe to an aftermarket one, I had to turn the Blitz
boost controller *down* in order to maintain the *same* boost as I had
previously been running. With the aftermarket downpipe, the backpressure
on the turbine housings was less and thus the turbos built boost more quickly
and operated more efficiently, resulting in quicker spool and higher sustained
boost to redline. All with the *same* boost controller settings.
> So it doesn't say anything unless you want to see where the turbos are
> dropping off. But they will not when the controller is set at 0.8 bars
> as then boost always stays the same.
As I said before, the controller has not setting to say, "Scotty, make my
boost 0.8 bars". Thus boost does not stay at 0.8bars when things
change.
> But you forget many other factors like the 9b running out
of
> the efficiency fields and producing a very high intake
>
temperature.
No I'm not. I'm just reporting what I saw in my experiment and intake
air temp was not relevant at the time. I was only remarking about boost
pressure seen in the manifold. I wasn't talking about total power output
or knock threshold or anything else... I imagine that my compressor outlet
temps are a little higher with the cat installed compared to running with a
testpipe, but that remains to be tested.
> Of course you take care of this with the water injection. But to
be
> honest, what is the WI for when you only run 0,8 bars of boost with
a
> 6500 rpm boost of 0,6 ? This just sounds odd to me.
I *just* got the WI installed under 2 weeks ago :-) I'm still playing
with it and getting flow rates adjusted before I run over 1.05kg of boost.
The 0.80kg is because that was all I was able to run previously if I wanted to
keep spikes under 1.05kg. The 0.65kg at redline is more a function of the
flow rates of the stock 9b turbos, as best as I can tell. That also seems
consistent with just about *every* other person with a relatively stock car that
I've talked to.
- --Erik
------------------------------
Date: Thu, 13 Feb 2003 10:55:59 -0000
From: "Jeff Lucius" <
jlucius@stealth316.com>
Subject:
Re: Team3S: Is it true cylinder #1 runs hotter?
Brian,
I assume you are referring to Graham's Chapter 14 "The air inlet system"
and
specifically his discussion of inlet manifold plenum design on pages
226-299.
Graham Bell is certainly one of the supergurus when it comes to
explaining
and documenting high-performance tuning. I have both of his books
on this
subject.
Of course I believe and trust Graham also. But in this chapter he is
referring mostly to improving the intake design when converting a normally-
aspirated engine to forced induction. Note his phrase on p. 228 "... but once
we massively increase the air flow large imbalances begin to show up."
I am not trying to discourage developments of improvements in our intake
system. But just like the search for "ram air" and "cold air" intakes,
engine
performance is often only slightly, if at all, improved by increased
efficiency or improved quality of these particular items on our turbocharged
models.
The exception is of course what Graham mentions as the most important -
*restrictions* in the system. For us this would be the MAS (stock MAS causes
a 1-2+ psi drop at the 400-800 cfm flow level), intercoolers (again a 1-2+
psi drop depending on model), and throttle body (Graham suggests a 75-mm
throttle plate for 600 turbocharged bhp; ours is about 60 mm, which Graham
suggests for about 365 turbo bhp).
Our plenum likely presents no huge restriction but also is not perfect. For
example, the entry opening to our plenum is only 2-3/8 inch or 60.3 mm, and
the "taper" from that opening ends after only two runners.
Again, I have not been following this discussion closely (having missed
Roger's mention of the closed intake valves) but I don't think there has
been
any widespread evidence of any particular cylinder running hotter than
another. An EGT pyrometer place at the beginning of the exhaust manifold
runner for every cylinder, in several different engines, and a datalogger
system would be a start to documenting if this occurs and to what extent.
However, the overwhelming failure of the 6G72 block is bearing failure, not
burnt valves, pistons, or rings in one particular cylinder.
- ---------- Original Message -------------
Subject: RE: Team3S: Is it
true cylinder #1 runs hotter?
Date: Wed, 12 Feb 2003 15:38:57 -0800
<snip>
I dunno. I'm just posing the question - I don't have the
answers. :) I
read in what I consider to be an authoritative
source ("Forced Induction
Performance Tuning", A. Graham Bell) that an
intake plenum designed like ours
will tend to result in more air to the
cylinders furthest from the throttle
body. Bell states that you can
counter this effect by tapering the main
plenum area, or by opening up the
mouths of the runners closes to the
throttle.
The discussion so far on a DIY EFI list I subscribe to suggests that simply
flow testing the plenum won't give the full story. The pressure waves
from
opening/closing valves make the problem much more complex.
None the less, it seems that there is some merit to this idea of unequal
air
distribution. I trust the Bell book quite a bit, and I've seen
aftermarket
plenums for other cars use this tapering strategy. What we
need to figure
out is whether it'd be worth it for _us_ to undertake a
plenum redesign. :)
- - Brian
------------------------------
Date: Thu, 13 Feb 2003 08:39:31 -0500
From: "Starkey, Jr., Joseph"
<
starkeyje@bipc.com>
Subject:
RE: Team3S: Is it true cylinder #1 runs hotter?
I'm not sure that equating it to the fuel piling up is the same (since
fuel, being a liquid, is not compressible like air). But Jeff raises an
interesting point. Wouldn't this equalize the intake pressure throughout
the plenum, thus equalizing airflow? That is, each cylinder would get a
burst of air at the same relative pressure and volume as the corresponding
intake valve opens.
- -----Original Message-----
From: Jeff Lucius
[mailto:jlucius@stealth316.com]
Sent: Wednesday, February 12, 2003 6:07
PM
I have not been following this thread closely, but it looks like somebody
thinks that unequal flow through the plenum and runners may put more air into
one cylinder than another and thus tend to make that (those) cylinder(s) run
leaner (assuming equal fuel distribution). If this is the case, then how do you
account for the following.
In the DOHC 6G72, the intake valves are closed ~65% of the time (using
gross duration of 251º) or not flowing much air ~71% of the time (using ~208º at
0.050" lift). This means air is basically just piling up (*not flowing*) in the
manifold and runner in front of the valves (for one cylinder), **just as the
fuel is**, at least 65% of the time (that would be ~39 seconds out of a minute
broken into RPM/2 pieces). So how does this factor into all the flow and flow
distribution theories?
The PCV channel under the intake manifold connects all six ports. How does
this affect flow equalization?
------------------------------
Date: Thu, 13 Feb 2003 14:52:19 -0000
From: "Jeff Lucius" <
jlucius@stealth316.com>
Subject:
Re: Team3S: Is it true cylinder #1 runs hotter?
>> since fuel, being a liquid, is not compressible like air
I mentioned the fuel "piling up" not to compare it to air "piling up" but
to
1) note that the intake valves are also closed during much of the fuel
injection activation time when the engine is under load, and especially
during
WOT operation, and 2) motivate additional thought concerning the
timing and
progression of events in our engines.
>> Wouldn't this equalize the intake pressure
>> throughout
the plenum, thus equalizing airflow?
I really don't know. I am not sure air will "back up" far enough from the
valves between valve openings to actually flow back into the manifold and
plenum. The PCV channel does connect all six runners in the intake manifold
and so will permit some flow of air between runners whenever there is a
pressure difference. Note that when the manifold is pressurized there should
not be flow out of the manifold and past the PCV valve into the front rocker
cover. However, the small size of this channel probably precludes the rapid
pressure/flow equalization that would be required at high engine speeds (at
6000 RPM there is 20 milliseconds between valve openings).
But what is true is that the air is *not flowing* in the head ports the
moment
the two valves open. I don't know how far back into the manifold and
runners
this "puddle" of air extends. But then, this is the very reason that
valve
seat and stem design, valve configuration, and piston crown design are
so
important to proper flow and mixing of air and fuel in the cylinder. And
it is
also the reason that "flowability" is so important. When the valves do
open,
we want it as easy as possible for the air to flow through the head
port and
into the cylinder.
What volume of air flows into one cylinder of our 2.972L/181CI engine? That
would be about 30 cubic inches if there is ~100% filling of the cylinder. 30
CI is about 16.6 oz. Imagine a 16-oz bottle of your favorite beverage. Now
imagine how we could fit that bottle in the head port, intake manifold, and
plenum runner. I am guessing that the head port and manifold would be filled
and the volume would extend a little way into the plenum runner. It is these
areas that need to be optimized for filling of the cylinders. Areas before
that (from plenum to air filter) need to be optimized only to the extent
that
the "16-oz" area is kept supplied with air.
One way to possibly test the flow characteristics of our plenum is to
observe
the amount of crud buildup in the intake manifold. This crud is
likely due in
part to the injection of carbon-rich exhaust gas through the
EGR port next to
the entry to the plenum. Is there more build up near
cylinder 6 or near
cylinder 1, or is it evenly distributed? But this may not
really be a fair
test because EGR occurs only during cruise (low to moderate
airflow) and not
(deliberately) during WOT operation (high airflow). On the
other hand, the
oily aerosol coming from the rocker cover through the PCV
valve may be
contributing to the crud buildup. If this is the case, we could
expect more
crud near cylinder 6, which is closest to the PCV valve.
Just some food for thought. :)
------------------------------
Date: Thu, 13 Feb 2003 15:26:40 -0000
From: "Jeff Lucius" <
jlucius@stealth316.com>
Subject:
Re: Team3S: offlist...
Flow testing does not "really tell". It does measure the flowability of the
heads, or manifold, or plenum, under the very specific and usually very
unrealistic condition that there is constant flow through the object. This
is
*never* the case for the heads and manifold when the engine operates.
With the
intake valves close 65% of each 4-stroke, 720º cycle, air is
cyclically
flowing then stopping forming a dynamic situation that cannot be
duplicated on
a flow bench.
This is not to say flow testing is not useful, because it is. Flow testing
is
good to evaluate the optimization of the air paths for when the air *is*
flowing, which is continuous from the air filter to somewhere in the plenum
runners, and in the manifold and heads when the intake valve is open.
However,
flow testing cannot completely predict the dynamic response of the
heads and
manifold, and maybe the plenum, after flow work. Just as the
exhaust system
(especially the manifold) responds differently for varying
exhaust flow
volumes and exhaust pulse rates (engine RPM), so do the intake
manifold and
heads.
As far as the boat in the water stuff. We need to deal with compressible
air
not water. Without even getting into the theory of fluid vs. aero
dynamics,
just consider aircraft bodies for a moment. Is it better or worse
for
aerodynamic efficiency to have a smooth or rough exterior? Yes, that's
right,
smoother is better for higher efficiency (less pressure loss). The
rules are
the same for wings, turbo wheels, plenum runners, or car bodies.
As surface
roughness increases so does pressure loss as air flows across
that surface. I
don't know why someone would roughen the surface a turbo
port. It may be for
increased heat dissipation without appreciably affecting
airflow because after
the turbo the air speed is so slow that *minor* (like
240 grit) surface
roughness has little affect on pressure loss. I can say
that turbo
manufacturers strive for the very smoothest compressor wheel
surface they can
get because of the very high air speeds (up to the speed of
sound).
- ----- Original Message -----
From: "Damon Rachell" <
DamonR@mefas.com>
Sent: Wednesday,
February 12, 2003 3:37 PM
All this talk makes me thing that porting is far more important than
polishing heads. I'll have to check with some friends who professionally
port and polish. Maybe this is new info and should replace the old school
opinions! I'm guessing flow testing is the only way to really tell.
Is it possible to test flow velocity as well as volume on a flow
bench?
- ----- Original Message -----
From: "glenn vrfour" <
vr4glenn@yahoo.com>
Sent: Wednesday,
February 12, 2003 1:58 PM
> Interesting point. Sometime back was watching special
> on
the America Cup sailboat races. They found that
> putting small
ridges on the hull made the boat faster
> than the hull was completely
smooth. I think that a
> small amount of water would be trapped,
then it was
> water on water instead of hull on water...
>
>
I'd imagine same is true for the intake charge.
>
>
Glenn
>
> --- Damon Rachell <
DamonR@mefas.com> wrote:
> > Some
surface roughness is actually preferred over
> > polished smooth
surfaces. At the Garrett lectures
> > two weeks ago in Torrence,
CA, they discussed this
> > in some detail. Basically, polished
surfaces
> > provide more turbulence than slightly rough ones.
>
> The theory here is that there is a cushioning layer
> > at the
roughened surface which provides less
> > friction than that of a
polishes surface.
<snip>
------------------------------
Date: Thu, 13 Feb 2003 10:25:20 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Is it true cylinder #1 runs hotter?
Jeff -
That's exactly the chapter and discussion I was referring to. I don't
specifically recall the disclaimer about his intake design suggestions being
meant for NA to forced induction conversions. I believe you that it's
there, though! :) I'll go give it a re-read tonight. I
completely agree with removing significant restrictions being the most important
improvement we can make to the intake system. I can attest to a seat of
the pants improvement after removing the MAS.
This whole discussion started as a musing on whether certain cylinders tend
to run hotter. There's a sort of 'tribal knowledge' in the 3/S community
that one cylinder or another (depending on who you talk to) runs hotter because
of fuel delivery problems or cooling problems or any number or other
hypotheses. Problem is, tribal knowledge is often just chicken bones and
voodoo. I haven't heard any of those claims backed up by controlled
experiments or solid reasoning.
After reading the Graham book, the plenum design bit struck me as a
reasonable possible cause for certain cylinders getting more air, and thus
running lean. So, I figured I'd throw it out for discussion. To be
honest it was fairly self-interested, because with the AEM EMS I can explicitly
compensate - with per cylinder fuel trim - for any air delivery
difference. I don't think the intake plenum presents any significant
restriction. The only reason for a redesigned plenum would be if it were
causing significant inequalities in the amount of air getting through the heads
and into the cylinders.
Actually, based on Bell's throttle size recommendations, a larger throttle
would be a valid reason for modifying the plenum. If the airflow is pretty
much equal to all cylinders, then this is about the only reason I can think
of. :)
- - Brian
------------------------------
Has anybody seen or heard of these turbos before?
They are ported very
large! and the horse power he claims they make...?
------------------------------
There's been some discussion on the 3SI.org board on these turbos. I
know people have purchased them, but I don't remember hearing much in the way of
real-world results yet. Do a search for "phantom" on the 3SI board and
you'll see at least a couple long discussions.
------------------------------
Date: Thu, 13 Feb 2003 10:31:54 -0800
From: "Geddes, Brian J" <
brian.j.geddes@intel.com>
Subject:
RE: Team3S: Is it true cylinder #1 runs hotter?
To be honest, I didn't know that the PCV channel connected all six runners
after the intake plenum. If this is the case, and it's a non-trivial size
(ie not a pinhole or small diameter vacuum tube), then it seems to me that the
plenum design becomes less important.
- - Brian
------------------------------
Date: Thu, 13 Feb 2003 11:39:07 -0800
From: "Tyson Varosyan" <
tigran@tigran.com>
Subject: RE:
Team3S: new turbos?
I don't know... Look at the size of wheels on turbochargers.com Look at the
stock wheel and at what they are putting in... They had to have milled A TON of
metal out of the housing to fit that. How thick are the sidewalls now? Remember
how hot those things get? Remember how much stress is on those housings from the
100lb exhaust hanging on them? I want to see what happens with these when they
are used...
Tyson
------------------------------
Date: Thu, 13 Feb 2003 14:48:47 -0500
From: "Furman, Russell" <
RFurman2@MassMutual.com>
Subject:
RE: Team3S: new turbos?
Tyson IIRC they are not using the stock td04 housing but rather the TD04L
housing. So they may work with out having a catastrophic turbine housing
failure or they may not. The amount of pumping losses occurring at higher
boost pressures is another issue all together.
I am not a fan by any stretch of anything larger than a 15G using a 6cm
housing, I can almost excuse a 17G but the 368's....... Not on my car just
too much being lost and all I am gaining is slightly better spool....
Spool can be improved by headwork, better designed manifolds, playing with
timing, and if the budget allows a slight increase in static compression (forged
pistons)
Russell F
CT
- -----Original Message-----
From: Tyson Varosyan
[mailto:tigran@tigran.com]
Sent: Thursday, February 13, 2003 2:39 PM
I dont know... Look at the size of wheels on turbochargers.com Look at the
stock wheel and at what they are putting in... They had to have milled A TON of
metal out of the housing to fit that. How thick are the sidewalls now? Remember
how hot those things get? Remember how much stress is on those housings from the
100lb exhaust hanging on them? I want to see what happens with these when they
are used...
Tyson
------------------------------
Date: Thu, 13 Feb 2003 20:57:28 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: new turbos?
The 368s use a bored out turbine housing. I forget to take the measures
when I installed them but the larger turbine was well visible. There is about
1000rpm more lag compared to the 9b.
> I am not a fan by any stretch of anything larger than a 15G using
a
> 6cm housing, I can almost excuse a 17G but the 368's....... Not
on my
> car just too much being lost and all I am gaining is slightly
better
> spool....
>
> Spool can be improved by headwork,
better designed manifolds, playing
> with timing, and if the budget
allows a slight increase in static
> compression (forged pistons)
------------------------------
Date: Thu, 13 Feb 2003 12:43:28 -0800
From: "Damon Rachell" <
DamonR@mefas.com>
Subject: Re: Team3S:
new turbos?
Not to mention, it's the same wheel as the GT368 in the stock housing!!!
The diffuser area is reduced to practically nothing! If you want some
answers (one's that I'm not technically included enough to answer), talk to
Brian at GTPRO and he'll tell you why the 368 comes in a whole new compressor
housing, not the stock one. I know it's a reason of efficiency, but where
the efficiency comes from and what problems lower efficiency cause, I don't
know.
Damon
- ----- Original Message -----
From: "Tyson Varosyan" <
tigran@tigran.com>
Sent: Thursday,
February 13, 2003 11:39 AM
> I dont know... Look at the size of wheels on turbochargers.com Look at
> the stock wheel and at what they are putting in... They had to have
> milled A TON of metal out of the housing to fit that. How thick are
> the sidewalls now?
>
> Remember how hot those things get?
Remember how much stress is on
> those housings from the 100lb exhaust
hanging on them? I want to see
> what happens with these when they are
used...
>
> Tyson
------------------------------
Date: Thu, 13 Feb 2003 22:28:27 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: new turbos?
The 368 turbos are hybrids as the compressor wheel is a size in the 20G
region ! You can't fit such a wheel into the housing of the compressor side of a
TD04L.
- ----- Original Message -----
From: "Damon Rachell" <
DamonR@mefas.com>
Sent: Thursday,
February 13, 2003 9:43 PM
> Not to mention, it's the same wheel as the GT368 in the stock
>
housing!!! The diffuser area is reduced to practically nothing! If you
> want some answers (one's that I'm not technically included enough to
> answer), talk to Brian at GTPRO and he'll tell you why the 368 comes
> in a whole new compressor housing, not the stock one. I know it's
a
> reason of efficiency, but where the efficiency comes from and what
> problems lower efficiency cause, I don't know.
------------------------------
Date: Thu, 13 Feb 2003 14:13:18 -0800
From: "Damon Rachell" <
DamonR@mefas.com>
Subject: Re: Team3S:
new turbos?
You would think so, but according to their website, it's a T3-60 trim wheel
in a TD04L! So, somehow they DO make it fit. Efficiently?
Structurally strong? That's up to the laws of nature to determine.
- ----- Original Message -----
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Sent:
Thursday, February 13, 2003 1:28 PM
> The 368 turbos are hybrids as the compressor wheel is a size in the
> 20G region ! You can't fit such a wheel into the housing of the
> compressor side of a TD04L.
>
> Roger G.
> 93' &
96'3000GT TT
>
www.rtec.ch
------------------------------
Date: Thu, 13 Feb 2003 23:18:23 +0100
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Subject:
Re: Team3S: new turbos?
The TD04L is telling about the turbine wheel housing and the body ... NOT
the compressor wheel housing ! BTW ... I have the 368s on my car (the one before
the sx models).
Check out my homepage under project where I have some old pictures of them
compared to the stock turbos.
- ----- Original Message -----
From: "Damon Rachell" <
DamonR@mefas.com>
Sent: Thursday,
February 13, 2003 11:13 PM
> You would think so, but according to their website, it's a T3-60 trim
> wheel in a TD04L! So, somehow they DO make it fit.
Efficiently?
> Structurally strong? That's up to the laws of nature
to determine.
------------------------------
Date: Thu, 13 Feb 2003 15:34:48 -0700
From: "Trevor James" <
trevorlj@cox.net>
Subject: Re: Team3S:
new turbos?
268's are actually about the same size as 16G's compressors...with a
smaller turbine wheel and turbine housing.
Trevor
- ----- Original Message -----
From: "Roger Gerl" <
roger.gerl@bluewin.ch>
Sent:
Thursday, February 13, 2003 2:28 PM
> The 368 turbos are hybrids as the compressor wheel is a size in the
> 20G region ! You can't fit such a wheel into the housing of the
> compressor side of a TD04L.
>
> Roger G.
> 93' &
96'3000GT TT
>
www.rtec.ch
------------------------------
End of Team3S: 3000GT & Stealth V2
#80
**************************************
