Newbie Tuner / GCC questions

[laser92awd]

I've had my '92 AWD Laser since late '91. Over the years I've done these performance upgrades:

16G Ported & Clipped
Upgraded in-take fuel pump (Buschur)
VPC (original model with stock prom)
2G Manifold
Porting
IC Piping Upgrade
2.5" exhaust all the way back
Alamo upgraded sidemount intercooler
Straight pipe air intake with big K&N - BOV vents/crankcase filter/etc.

I think you guys can picture it - basically a full 16G bolt-on package with nothing done to the engine. Everything on the car is working great - no check engine codes and all solenoids & switches appear to be working. The car does not buck and I do not hear any audible detonation.

After all these years of guessing (watching boost, O2, & EGT gauges) I decided to get a pocketlogger so I could really know what's going on.

Every time I check my spark plugs they are on the black side - not so far as being fouled, but blacker than a standard plug might be. And my exhaust tips are always coated solid black on the inside. When I stand on the throttle black smoke comes out the exhaust. Back when I bought my VPC & intank fuel pump Dave Buschur highly recommended I run the stock prom in my VPC which I have done ever since. I have never done anything with the stock fuel pressure regulator and have stock injectors. I run 93 and 94 octane pump gas.

So after I give you some numbers, I am wondering if you guys could suggest where I need to go next. A GCC to fine tune the VPC? A different VPC prom? Bigger injectors? If it's not broke don't fix it?

[THE NUMBERS]
Rather than plot out a zillion numbers, I am only going to give the final numbers at the end of 3rd gear @ redline and then say whether the numbers were higher, lower, or the same prior to redline in 3rd gear. Hope this makes sense:

93 Octane Pump Gas

From Gauges:
18psi - rock solid through entire run
79F outside temp, 85% humidity
EGT says 850C was maximum temp

From Logger: (3rd gear when I hit 7000rpm)
Knock = 16, this was highest of run (lowest was 0)
Timing = 15, started at 20, gradually lowered to 15
O2 = .84 rock solid through entire run
Injector P/W = 15.385ms, started at ~18 gradually lowered to 15.385

Please if you've been down this same road let me know your ideas as to what I should do (if anything). And I'm very interested in figuring out how (if) a GCC could help me. If I'm running a solid O2 reading through the entire run would a GCC really do anything? Would larger injectors & a new VPC prom give me more power or only reduce the EGT temperature/raise the O2 value?

I raced a bone stock 2001 C5 corvette (350HP?) several times yesterday (rolling start 2nd & 3rd gears just for pure power comparison) and stuck with him like glue. There were times during the run I would pull on him and times during the run he would pull on me. Dead even at the end. Very closely matched IMO. Does that sound right for my setup with the numbers I'm running?

Thanks everybody!

 

[NJGSX96]

I think you can tune your setup a little better. No need to change yet. Sounds like you have a good base to start with. i think you can mess with the VPC a touch to possibly get a little more out of your car before you need to add anything else.

Your timing should increase for 15-20, not decrease from 20-15. Can you tell me your knock and timing throughout your run? This can help me help you a little more.

Going larger injector and new prom is an idea, but I would recommend a GCC or, my preference, a S-AFC as well for better tuneability.

What do you have the VPC set at? Gain, idle and response wise?

 

[laser92awd]

MY VPC SETTINGS:
RESPONSE: MAXIMUM
GAIN: MINIMUM
IDLE: STRAIGHT UP

If I lower response the car has a delay when I hit the gas. If I raise gain more than a couple clicks I get fuel cut for some reason. Idle doesn't seem to make much difference no matter where I set it. These were my first runs - I wanted to establish a baseline and understand my tuning options before I started making lots of runs with different settings.

While crusing my timing is around 40. Wouldn't it be logical that the timing would decrease as the rpms increase as the engine retards the timing, especially since my knock sensor is showing some level of activity?

Thanks!

Originally posted by NJGSX96
I think you can tune your setup a little better. No need to change yet. Sounds like you have a good base to start with. i think you can mess with the VPC a touch to possibly get a little more out of your car before you need to add anything else.

Your timing should increase for 15-20, not decrease from 20-15. Can you tell me your knock and timing throughout your run? This can help me help you a little more.

Going larger injector and new prom is an idea, but I would recommend a GCC or, my preference, a S-AFC as well for better tuneability.

What do you have the VPC set at? Gain, idle and response wise?

 

[NJGSX96]

"While crusing my timing is around 40. Wouldn't it be logical that the timing would decrease as the rpms increase as the engine retards the timing, especially since my knock sensor is showing some level of activity?"

You don't really want any level of activity from your knock sensor. 40° at cruising is normal. When you nail that throttle, you want it to hit 14-15° and rise up to around 19-22° on pump gas. You don't want the engine to retard timing, but rather advance it. My guess is that you are tuned alright, but when boost comes on, your car can't supply enough fuel so as the rpms go up, so does your knock. That or you are getting too much fuel (which as the problem I had) and it does the same thing and pulls timing.

Try to lower your boost to around 16psi and log and see if there is a difference. On lower boost, you should get better timing advance. Do that and see what happens.

 

[NJGSX96]

I just re-read and saw that your car puts out black smoke... on 15IPW and .84 O2? That is odd. Was too early in the morning before. Let me think this one over again.

 

[laser92awd]

I think the smoke is more when I nail the throttle and through some of the run. I don't know if it is still putting out black smoke at redline. Maybe, maybe not. Never looked at that.

For comparison I turned the boost down to 15psi. Everything was exactly the same except for these values:

15 PSI RUN:
EGT went to slightly above 800C instead of 850C.
From Logger: (3rd gear when I hit 7000rpm)
Knock = 21, this was highest of run (lowest was 2)
Timing = started at 18, raised to 20 in middle, ended on 17
O2 = started at .82, raised to .84 in middle, ended on .82
Injector P/W = started at 15.385ms, hit a peak of 16.410 just before the middle, and ended on 15.385ms

Funny, the 15psi run seemed more lean & with slightly higher knock, although timing wasn't pulled back as much.

(curiously this run showed a rising slope, middle peak, and declining slope throughout the 3rd gear log)

Originally posted by NJGSX96
I just re-read and saw that your car puts out black smoke... on 15IPW and .84 O2? That is odd. Was too early in the morning before. Let me think this one over again.

 

[NJGSX96]

Those are the kind of logs I get. You hit your peak timing around 5500-6500rpm?

How did the car feel power wise? Did it pull hard?

What is odd is that you lowered boost and didn't touch the fuel, yet you ran leaner than on more boost. Should be the opposite.

 

[laser92awd]

Yes, the peak of 22 was at 6218rpm. I have no idea why it ran leaner unless maybe the air charge temp was higher and I can't measure that.

So do you think my setup is as good as it is going to get? My car feels strong and pulls hard. I'm just trying to fine tune it as much as possible so I don't have any wasted power.

Thanks!