AWD Turbo Parts and Performance

Posts tagged “DSM

Marc S – Racing / Comparison with Eric Lu’s 95 GSX – Third Race

Just thought I’d give everyone an update on the latest modded-95
comparison that Eric & I did. As a refresher, Eric’s 95 has historically
had a lot more mods than mine, but his car hasn’t been any quicker. The
difference between this 3rd race and the prior one is that Eric replaced
his “late 95″ ECU with an earlier, non-California ECU, and added a front
mount intercooler. Here’s the current list of mods on our cars-

My 95 GSX: K&N FIPK, Magnecor 8.5mm wires, RSR 3″ Exhaust,
IM Intercooler pipe & BV upgrade, and a drilled wastegate solenoid

Eric’s 95 GSX: K&N FIPK, Nology Hotwires, Trust 2.5″ Exhaust,
custom Int pipe & BV upgrade, test pipe, Buschur 2.5” downpipe,
EVC (16 psi), secondary fuel pump, front mount intercooler,
ported exhaust manifold & O2 housing, turbo: Super60 compressor
(similar in size to a 16g), “T28” exhaust wheel w/ 10 degree clip,
ported turbo housings

We got together last night at our usual street-racing site. (Out of town
& deserted). Eric brought a couple friends which was definitely helpful
for flagging the start of each race. Temps were around 70 degrees.
Like usual we both maxxed our gas tanks at the same gas station.

We got in 4-5 good runs. The results? Well, it’s a loss I can be
happy about- Eric’s car has woken up and is finally starting to pull.
Every single run netted near-identical results. First gear and second
gear were relatively even, with Eric pulling maybe half a car or so
at the end of second. As soon as we shifted to third it was all over-
Eric’s car quickly walked away. By the shift to 4th he was usually 5-6
car lengths ahead (but once we were both in 4th he usually maintained
but did not increase his lead). We took the cars up to between 100 &
110 (I was in the lower 100’s, Eric the upper). (As a comparison,
by the way, the 600SL I raced did not pull away in 3rd gear even half
as quickly as Eric did.)

Thoughts on the results.. First, I like the fact that every run had
almost identical results with only a car length of variation at the
end of each run. I still think Eric’s car should be pulling a little
more in 1st/2nd. While clearly I can no longer keep up with Eric
like I used to, we both think he still has problems to work out.
Running beyond 16psi is apparently leaning things out and causing
temps to rise, and I just don’t see how that should be the case with
4550cc injectors, a secondary fuel pump, and a smaller-than-average
(compared to 1st gen’s) performance turbo.

The changes since this race and last were the intercooler and ECU on
Eric’s car. Eric installed the intercooler a few days before the ECU and
noticed no difference. When he put the new ECU in, his car ran
nicer (I’ll let him expand on this if he wants), and suddenly he’s
beating me by 5 car lengths. Personally, I still don’t buy into the
“major code changes” between the early & late ECU’s. When we first
started modding these 95’s, we all had problems with the boost falling
down to 10psi no matter what we did, and somewhere along the way the
ECU started getting blamed. Clearly the PSI drop is a result of the small
Garrett turbo, not the ECU. I don’t know of any cases that demonstrate
an actual performance difference between the 2 ECU’s, we only know
that the earlier one is easier to modify due to having a standardized
chip with the spark/fuel data, and the later one having all that info
integrated on a single, custom Mitsubishi chip. Still, I’m hard
pressed to explain why the ECU change helped Eric out so much. Perhaps
his original ECU had something wrong with it, or somehow locked itself into
one of those limp-modes due to his cat being bypassed. The latter
would be my best guess, perhaps the later ECU’s or California ECU’s
are more finicky about the 2nd O2 sensor. (I should like usual point out
that this *whole* evaluation is of course strictly conjecture,
to be taken with a grain of salt. We still have yet to get to a real
race track).

Other variables.. Eric & I both have stock clutches. He’s probably
losing a little of his power to a slipping clutch, which could explain
why we’re so close in 1st/2nd gear. We’re slowly killing these types
of variables though.

For our next meet, we plan to make the journey to a racetrack (Carlsbad)
and get some real numbers. We should both have performance clutches
installed by then. In addition, I plan on adding a few major mods-
a 3″ downpipe, a 3″ cat, and a 16G turbo. My hope is to kick Eric’s
butt and still be running with a cat :). I’d really like to see
Eric do runs at the track with his current turbo, and then a TD05 16G
(with no other changes); at least we could find out what kind of difference
there really is.

On a final note, there’s nothing more we can really “prove” regarding
early/late ECU’s. While I had been under the impression that I had
a Jun 95 (“late”) ECU, we checked and found that I in fact have a
Jan 95 (“early”) ECU. (This car really must have been sitting around
considering I purchased it November 95). I’m sorry I can’t bury the
myth when I go run decent numbers at the track in a couple months
(grin… thinking positive). Admittedly though, I am happy to know my
ECU is more easily modified should I wish to re-program it at a later
date.

’nuff rambling.

Marc S.


Marc S – Racing / Comparison with Eric Lu’s 95 GSX – Second Race

As a refresher, Eric (EricATCA) and I got together a few weeks ago
to see how our cars would fare against each other. We both have 95
Eclipse GSX’s. Eric’s GSX had several more mods (including a downpipe,
cat bypass, and much bigger compressor wheel in his turbo) yet the cars
were at best dead equal; usually I pulled a car length or two on him.
There were no definite answers to the “why”, but one thing that was highly
suspect was Eric’s turbo- it had no modifications to the exhaust side
yet had as big a compressor wheel as could fit in the stock compressor
housing. It definitely had heavy lag.

Since then, Eric has upgraded the turbine wheel plus give it a 10 degree
clip, ported the turbo housings, and had the exhaust manifold/wastegate/O2
sensor housings ported. We hoped the work on the exhaust side of the
turbo would make the difference, and that his car would pick up some
serious power.

We got together again this weekend, on a street outside of town where
people have been meeting for street races for at least a decade
(probably a lot longer). It’s a nice long (well over a 1/4 mile)
deserted street, and I felt comfortable racing out there in the daytime
when there wouldn’t be any other street racers around. Temperatures were
high, between 90-95 degrees. (Definitely no fun racing with windows
closed & A/C off!)

We got in around 12 runs for the day. We paid particular attention to
trying to eliminate as many variables as possible. We both filled up
at the same gas station (Chevron 92). Eric had a full tank, mine was
around 2.5 gallons shy of full to try and make up for driver weight
difference. In addition to runs off the line and rolling runs where
clutch work was involved, we also did several runs from both second
and third gear where the clutch was already fully engaged, to try and
eliminate variance in driving style. For the 2nd gear runs, we both
had the clutch fully engaged and the engines at 3500rpm when we stepped
on it. Same thing for third gear, except we did it from 3800 rpm.
Regarding boost levels, I think the runs were split around 50/50 between
Eric running at 18.5 psi & 15 psi. I have no boost control, but I have
hollowed out the nipple on the wastegate solenoid on the air box, which
allows me to spike up to 15ish psi (after which boost falls down as revs
increase).

Here’s the list of mods on the two cars. (An asterisk * denotes
changes since last time).

Eric’s 95 GSX My 95 GSX
K&N FIPK K&N FIPK
Nology Hotwires Magnecor 8.5mm wires
Trust 2.5″ Exhaust RSR 3″ Exhaust
*Imagine Motors Int pipe upgrade Imagine Motors Intercooler pipe upgrade
(Was an HRC unit last time)
Test pipe Stock catalytic converter
Buschur 2.5″ downpipe Stock downpipe
EVC (15, 18.5psi) Mod’d wastegate solenoid, +2psi over stk
Secondary (inline) fuel pump Stock fuel pump only
T25 w/ Super60 compressor Stock T25
*”T28″ exhaust wheel w/ 10deg
clip, ported housings
*Ported exhaust manifold, O2 & Stock manifold/housings
wastegate housings

As for the results… Unfortunately they are disappointing and create
more questions than they answer. The cars were very equally matched.
A couple times Eric pulled ahead of me by 0 to 1.5 car lengths, a couple
times I pulled perhaps a car length on him. Most of the time we were very
equal, with the person who happened to get their foot on the gas a
millisecond before the other person getting a nose up. I think the times
I got a little ahead were usually due to my turbo spooling up just a hair
faster (not including the other factors I’m about to mention), but
surprisingly there isn’t much more lag on Eric’s turbo than on mine. I’m
sure all else equal there is more lag there, but the downpipe, test pipe,
and ported exhaust manifold seem to offset the additional lag created by
the bigger wheels.

This time around I took Eric’s car for a drive to compare how it felt to
mine, so my comments re: lag are based on driving his car and then driving
my car.

Ok, now to the “other factors”.. We have some unknown variables here that
pretty much make this weekend’s testing moot, other than to say that
currently our cars are still pretty equal, whatever the reasons. The
first variable is a slipping clutch. Eric’s clutch does have a bit of
slip (When I did some harder shifts in his car, it was not as crisp as in
mine.) I never saw any major slippage, but minor slippage may be occurring.
Eric will be putting a Centerforce D/F in soon, so that should eliminate
the clutch variable. Ok, everything that follows is pure (educated?)
guesswork.

“Variable #2” is a complex one. It’s ECU related. It seems like
Eric’s ECU is retarding his timing, big time. In the races that started
in lower gears (1st, 2nd) where he pulled a little on me or kept up with
me, he was set at 15psi. When he was set at 18.5psi, I usually pulled
a car length on him. In the higher gear races (starting in 3rd gear),
using 18.5psi didn’t seem to hurt as much but it certainly didn’t help
much either. This is a definite sign of a problem, 18.5psi should have
given him a lot more power, not hurt him. He has a big compressor
wheel, going to 18.5 psi should show good gains. He hasn’t played with
the timing on the car yet, but is going to try retarding it a little
to see if that makes a difference.

I’m curious, by the way, if anyone knows the effects that the 2nd
O2 sensor behind the cat (in this case, test pipe) might have on the
ECU?.. Could running a test pipe from an ECU point-of-view be hurting
Eric? (I’m unsure if he even has his 2nd O2 sensor installed?…)

Anyways, to me, I don’t think it’s a matter of the performance parts
on Eric’s car slowing him down or not providing good performance. Take
a look down the list of mods on his car & you’ll note that every
part on there has been proven by many DSM’ers to increase performance.
And I have seen a 95 with a turbo nearly identical to Eric’s run some
impressive 1/4 mile times. A better clutch might help things a hair,
but there is something significantly wrong with how things are running.
What worries me is that there aren’t a whole lot of things to play with
to try and correct the problem. Any thoughts on the matter are
appreciated!

That about wraps it up. We plan to get together again in a few weeks
when the CF DF has been broken in, and after making some sort of change
(ignition retard?) that seems to make a power difference.

Thanks again Eric!

-Marc


Marc S – Racing / Comparison with Eric Lu’s 95 GSX – First Race

This weekend Eric (“EricATCA”) and I got together to compare 95’s.
(He has a T25 turbo with upgraded compressor wheel (Super 60)
& since I am in the market for a performance turbo, I wanted to see
how it ran). Eric’s a great guy, and it was a fun afternoon.
The performance results are somewhat surprising…

Here’s a description of the 2 cars-

Eric’s 95 GSX                              My 95 GSX
————-                                  ———
K&N FIPK                                  K&N FIPK
Nology Hotwires                         Magnecor 8.5mm wires
Trust 2.5″ Exhaust                        RSR 3″ Exhaust
HRC Intercooler pipe upgrade     Imagine Motors Intercooler pipe upgrade
Test pipe                                      Stock catalytic converter
Buschur 2.5″ down pipe                 Stock down pipe
EVC (was set at 16psi)                Stock (no boost control)
T25 w/ Super60 compressor        Stock T25

I really expected Eric’s car to leave me behind. The test pipe &
downpipe should have made a nice difference (25+ hp?), not to mention
consistent & higher boost from the EVC, and a bigger turbo flowing
cooler air.

The results though?… I was usually 1-2 car lengths ahead for the
duration of each race! The pattern was as follows- as soon as we
both stomped on it (almost all races were done from a roll)
my car would pull a little ahead. My smaller compressor wheel got into
boost a little earlier, enough to give me a car length usually. At
“upper midrange” we were around even, at upper revs Eric would start
to pull a little. When we hit second gear, it was “1st gear all over.”
I’d pull a little further on him initially and pretty much manage to hold
most of my gains. Towards the higher rev range he’d probably close a
little distance. We took it to the top of third gear once or twice,
but the results were still pretty much the same, the nose of his car
was behind my bumper from a few feet to 1.5 car lengths.

I should mention that also having been in his car as a passenger,
it definitely pulls a harder than my car from 4500rpm on up. I think
with a little better shifting the races would have been closer. But
that would mean 2 cars dead even when one has more mods..

Now, trying to sort out the why’s… Clearly a performance downpipe and
a test pipe give better performance and were helping him. Though the
EVC probably helped a bit as well (a little more boost + wastegate
held closed longer) for simplicity’s sake I’ll ignore any gains the
EVC should have been giving his car. That leaves: the Trust 2.5″
exhaust vs. my 3″ RSR exhaust, the HRC Intercooler pipe upgrade vs.
the Imagine Motors upgrade, and the upgraded T25 vs the stock T25.

I figure the RSR 3″ had to have helped me for some of that. We both
noted that in addition to the difference in pipe diameter, the Trust
exhaust has a relatively sharp bend near the muffler, and necks down
to 2 1/4″ where it meets the test pipe, whereas the RSR is very straight
throughout, and necks down to 2.5″

Intercooler pipe upgrade… I don’t feel as comfortable making any
claims here other than that the HRC upgrade only upgrades the area
from the intercooler up to the blow off valve, whereas the Imagine
Motors upgrade continues up from the blow off valve to the throttle body,
and replaces the stock throttle body elbow (which has a nasty sharp
edge/kink inside it) with a bigger/smoother elbow.

Eric & I felt that the T25 made the big difference. Upgrading
the compressor-side-only meant more lag, and because the exhaust side
stayed stock, it probably had too much backpressure building up there.
At the least the turbine wheel needs to be clipped. More likely the
turbine wheel needs to be upgraded as well. I’m unsure on whether
the compressor wheel shouldn’t be downsized as well to perhaps a
standard 60 wheel.

Eric will be upgrading the exhaust side of his turbo soon, with a bigger
turbine wheel and a clip. We’ll get together again and see exactly how
it affects things. Though I’m looking to upgrade a few items on my car,
I’m going to hold off until we can do this comparison. It’s important
to see what works and what doesn’t. I’m hopeful (and I’m sure Eric is
as well) that when his new turbo goes on and we meet again, that his
car will soundly take mine when we race. I’d hate to think that a
TD05 is the -only- way to go. I’d like to keep the T25 if possible
for the sake of warranty. So far all my mods are ok with my dealer,
but putting on a different turbo would probably change all that.

(Thanks again Eric!)

-Marc