I have a 1999 C5-Six Speed with 25k miles on it. I would really like to get the ATI setup.

After all the reading and what not I figure the best bet is the D trim model with 38 or 42# injectors.

So the real questionis tuning. I don't mind buying Autotap and LSedit. Being an Electrical engineer and working with cars for 10 years it shouldn't be that hard.

So now my questions...

I live in Boise Idaho, and there aren't any tuners here. There is a dyno though. I'm willing to buy the unit but need some tuning help. Is it really that difficult to get the 13:1 ratio on these things? Can't ATI or the vendors supply sample maps for use with LS1edit?

What is comes down to is: Can the ATI be installed and tuned by an individual, and later tuned futher (cam, headers). Or is this though an over simplification? :(

Is there a forum dedicated to sharing info about LS1edit? Where can I learn more about adjusting the fuel trims on my c5? What do the tuners change besides fuel trims?

Brian

1999 Pewter http://corvette.homeip.net

 

Well, after, seeing the ATI supercharger install by a friend and we took the unit out to send the computer to ED wright, he has done quite a few and his recalibration with out having the car was pretty close, this car runs great and idles well, i will hope to have the final dyno numbers and airfuel readings soon , but my butt dyno and other cars it is real close to 480hp, could be more , he has done a similar car on his dyno and got 505 hp with tuning and exhaust. i dont think you need anyother tuning. but on dyno with you car is the best for every last HP. we have 3 other cars ready to go and i will get numbers on all of them once the installs are done. i see other people have some trouble but over all the system seems to work well with outside tuning not the superchip they used to send with it.
'
:D

 

I've heard this SC is quite problematic with existing mods - the more you have, the more problematic it is. I would try and give Nick Agostino a shout. If you can catch him on a break from his busy schedule, perhaps he'll tell you all the problems he's had with existing mods and without.

 

13:1 is too lean, you want 12:1 for FI. You are hitting on the important points of successful FI tho. You need to learn to do it yourself. It really doesn't matter if you have a tuner close by. He won't be driving your car all the time.

Find a dyno with a Wideband O2. Work with a good programmer. Log data. You'll get there. Take it in steps.


[Modified by MelloYellow, 11:09 PM 7/16/2002]

 

I have asked myself the same question several times. It does seem to be a bit more complicated then one might initially think, but then again everything seems difficult until you have had a chance to experiment. I guess you just have to determine if the risk is worth it. I had originally thought about getting a baseline from someone like Ed Wright, but now I found out he locks the PCM after he is done. I’m still trying to decide on this and am not sure if the self tune thing is worth it in the long run.

A/F is more than just a single adjustment; it ends up being a combination of several different factors and tables. You will also need to adjust timing advance in a similar manner.

Here is a high level of outline of the approach that I would take. (I have never done this, so don't consider this accurate in any way. This is just based on my limited understanding of the PCM and what can be done with ls1-edit)

1. Adjust injector flow rate for new injectors.
2. Calibrate MAF until l & strims flatten out under part throttle operations
3. Start adjusting A/F for WOT with PE vs RMP knowing that you want to start a little rich
4. Scale back Spark Advance vs. RPM and Load to avoid knock
5. Start some WOT runs and subtract or add fule in PE vs RPM until you are in the 12:1 range
6. Advance Spark with Spark Advance vs RPM until you are as high as you can get without knock

There are also timing and fuel adjustments based on temp and MAP as well as several tables for knock retard.

It is enough to make your head spin and I’m sure the boost does not make it any easier. Probably not to bad if you are working from a baseline and just trying to tweak out a few extra ponies.

 

Nicks instructions to me were simple, install it and get a good tuning job, and that is what I am doing. I think a lot of people are experiencing problems with the microtuner that comes with the P1SC.

 

I used a stock PCM, MAF, 38lb lucas injectors and a MAFT plus a KB boost-a-pump/ATI inline pump and had pretty good results. My a/f was a flat 11:1 and I could move it with the MAFT +/- from 10:1 to 12.5:1 so there was even some adjustability. I did have to do some grinding in the MAF to lower its output at higher RPM but other than a rich cold start for a couple seconds (others I know didnt have the problem I did with the cold start with similar setups, I never did figure it out) the car idled perfect and still got 24mpg driving back and forth to the track (170 mile round trip).

Only other issue was the MAF was so far skewed my shifts were really soft and overheating the trans. The trans line pressure is calculated from MAF signal. I ended up puttinf a hobbs switch in so at 3psi of boost it opened a wire on the pcm (I forget which, been over a year) that would give full line pressure to the trans. Before I did that I was lucky to get 2 passes in without the trans going into 2nd gear only 'overheat' mode. After the hobbs switch I could make 20 passes on a 85 degree day with no problems.

LS1 edit didnt exist when I was doing the LS1 F body intercooled procharger (I was one of the first to get one) and I got dicked around by tuners for two months before I decided just to do it myself (with a little help from John at Pace parts and Just_Me from LS1.com). This time I'll use LS1 edit.

I made over 75 passes with the blower, 15 dyno pulls and probably over 100 n/a and never hurt anything. I kept the a/f overly rich at 11.5/11:1, I could have picked another 25rwhp by leaning on it but I used nothing but 92 octane fuel so I left it a little fat. I also had a tight converter, if I would have a 4000 conveter my car would have easily been in the 10s - but I'm sure the rear end would have broke (F-bods have weak rears). I ran the car with 1/2 a tank of gas, full CD changer, floor mats, super heavy 4" mufflex exaust (through converters as well), stock wheels with e/t streets and even the jack and spare (plus I weigh 235lbs and the blower added another 70lbs right over the front). I hit a deer with the car and destroyed the whole right side so I got pissed and took off all the mods (car only had about 7500 miles on it). I drove the car for almost another another year and it still ran/drove smelled like a new car when I traded it in recently :)

Sorry for the long post, I have read some so-so reviews of the C5 ATI kit but it is a good system, a little crude compared to some but they make power. I am leaning going to an ATI for the vette I just picked up, it has 76k on it so I wont be really agressive with it but I'll easily get in the 11's :)


[Modified by kp, 11:05 PM 7/19/2002]