I got 24 more HP over MTI's Mail order tune
12-08-2003, 05:18 AM
#1
I got 24 more HP over MTI's Mail order tune A friend of my bought a 2002 Yellow Z06 C5 a few months back and decided that "405" HP was just not enough... 
BTW - Bad azz car!!!
So he decided to get the Stage 2 LS6 Head and Cam package from MTI.
His mods are:
LS6 (maybe, could be LS1) Stage 2 Ported heads
X1 Cam 112 lsa
LT Headers
Underdrive Pulley
CatBack, not sure which one though
Mail order MTI Tuning
The sound of his car is bad azz, all around great sound from idle to WOT.
He had this one guy from the Dayton area to install his parts for him and he did a great job. From what I was told, the first MTI tune didn't want to work so they had to get another one, that one got the car running pretty good.
With that combo, I think his numbers at the track with stock tires were:
1.79 60' 11.9x @ 117 MPH
After our track day, he wanted to tweak a little more so he bought LS1 Edit.
So the other day, we got his car up on the dyno with the Wideband O2 up the tail pipe (not my favorite way of checking for air/fuel)
The first pull was 414 HP and the airfuel was around 11.8 thoughout the whole RPM range.
I hooked up LS1 Edit, to download MTI's mail order tune to see what's going on. 20 Minutes later, I could see why the HP was on the low side.
For total timing at WOT, it was only set to a conservative 22 degrees!
The car ran great, started everytime (hot and cold starts) and sounded great. So their tune was pretty good for being mail order.
After setting the timing to 28 degrees and playing with the air/fuel, we got it up to 438HP & 397 TQ at a 12.1-12.2 Air/fuel (tailpipe). I tried to lean it out some, but I was getting knock, it just liked the 12.1 number.
My personal opinion is that checking the air/fuel though the tail pipe is not as accurate as putting the wideband O2 in the header pipe. I've seen this many times before on my car and others, that the tail pipe is about .4-.6 leaner than at the header pipe.
Without having the stock file to compare to (which I told him to get from MTI, legally, that's his property) I could only go so far on the tuning. I didn't want to change some things if MTI already has.
I did notice one thing though, his IAC count was maxed at 310, this isn't normal on a C5 is it? I was using AutoTap.
Once he gets the stock file and he's talking about getting a ported TB, maybe with a little luck, we can hit 450 HP at the wheels with his current combo.
Bill
BTW - Bad azz car!!! So he decided to get the Stage 2 LS6 Head and Cam package from MTI.
His mods are:
LS6 (maybe, could be LS1) Stage 2 Ported heads
X1 Cam 112 lsa
LT Headers
Underdrive Pulley
CatBack, not sure which one though
Mail order MTI Tuning
The sound of his car is bad azz, all around great sound from idle to WOT.
He had this one guy from the Dayton area to install his parts for him and he did a great job. From what I was told, the first MTI tune didn't want to work so they had to get another one, that one got the car running pretty good.
With that combo, I think his numbers at the track with stock tires were:
1.79 60' 11.9x @ 117 MPH
After our track day, he wanted to tweak a little more so he bought LS1 Edit.
So the other day, we got his car up on the dyno with the Wideband O2 up the tail pipe (not my favorite way of checking for air/fuel)
The first pull was 414 HP and the airfuel was around 11.8 thoughout the whole RPM range.
I hooked up LS1 Edit, to download MTI's mail order tune to see what's going on. 20 Minutes later, I could see why the HP was on the low side.
For total timing at WOT, it was only set to a conservative 22 degrees!
The car ran great, started everytime (hot and cold starts) and sounded great. So their tune was pretty good for being mail order.
After setting the timing to 28 degrees and playing with the air/fuel, we got it up to 438HP & 397 TQ at a 12.1-12.2 Air/fuel (tailpipe). I tried to lean it out some, but I was getting knock, it just liked the 12.1 number.
My personal opinion is that checking the air/fuel though the tail pipe is not as accurate as putting the wideband O2 in the header pipe. I've seen this many times before on my car and others, that the tail pipe is about .4-.6 leaner than at the header pipe.
Without having the stock file to compare to (which I told him to get from MTI, legally, that's his property) I could only go so far on the tuning. I didn't want to change some things if MTI already has.
I did notice one thing though, his IAC count was maxed at 310, this isn't normal on a C5 is it? I was using AutoTap.
Once he gets the stock file and he's talking about getting a ported TB, maybe with a little luck, we can hit 450 HP at the wheels with his current combo.
Bill
12-08-2003, 07:27 AM
#2
Nice job Bill, but 28 degrees of timing may have been too much for that application to reach 13:1 AFR. There is more than one way to get AFR correct. And some cars make max power with less timing. Just have to fool around with different combinations to find what works. Good job though 
12-08-2003, 08:25 AM
#3
Todd,
I wanted the stock file to compare but I didn't have it, so I did the best I could.
You would think with it running on the fat side, 28 wouldn't be a problem, which it wasn't until I started to take fuel out. Maybe the wideband was flaky?
He's not done yet, I'm sure I'll be doing that car again in the next 5 months and with me getting more experience at tuning, I'll find more of those little tricks some of you guys know of.
I had to tune another car (that's another story) after that Z06 so I felt the tune was ok in this cold weather, having it any leaner might cause problems with using that tune in the summer time. Plus going up the tail pipe versus the header pipe is about .5 different in the air/fuel reading.
I wanted the stock file to compare but I didn't have it, so I did the best I could.
You would think with it running on the fat side, 28 wouldn't be a problem, which it wasn't until I started to take fuel out. Maybe the wideband was flaky?
He's not done yet, I'm sure I'll be doing that car again in the next 5 months and with me getting more experience at tuning, I'll find more of those little tricks some of you guys know of.
I had to tune another car (that's another story) after that Z06 so I felt the tune was ok in this cold weather, having it any leaner might cause problems with using that tune in the summer time. Plus going up the tail pipe versus the header pipe is about .5 different in the air/fuel reading.
12-09-2003, 10:32 AM
#4
TECH Senior Member
I'd take it to the track, make a few passes. Average the best MPHs. Then I'd drop the timing advance back a few degrees and lean the mixture 5%. Make passes, average MPHs. If no KR, lean 2-4% again and repeat the testing. Just keep playing with the mixture until you find the best MPH. Keep the timing advance just short of pinging regardless of what fuel setting you're using.
I think you would make better power at the track with the timing advance wherever it has to be to enable a 13:1 fuel/ratio.
BTW, what makes the best power on the dyno doesn't necessarily make the best power at the track or on the road. My best trap speeds with this '02 came with tuning quite a bit different that what we came up with on the dyno.
I think you would make better power at the track with the timing advance wherever it has to be to enable a 13:1 fuel/ratio.
BTW, what makes the best power on the dyno doesn't necessarily make the best power at the track or on the road. My best trap speeds with this '02 came with tuning quite a bit different that what we came up with on the dyno.
