[Z06] Tuning Problems
Thread Starter
Heel & Toe
Joined: Oct 2008
Posts: 19
Likes: 0
From: wellsville PA
Tuning Problems
2003 Z with Grantelli MAF, LS2, Fast 90mm, G5x3 cam, LT headers and 25K miles. Cam was installed by my Tuner who base lined the car at 390 max power and 372 maz torque. It appears a MTI -G cam was in the car (by others) and we put the G5x3 in. The Car had some minor idle issues before but was very driveable. After the cam install and 8 hours of tuning (per the Tuner) the car makes basically the same numbers and has "stumbling" idle issues as soon as I give it gas off the initial start up idle at 1K rpm. I've called and talked to LG and read numerous Forum threads that say the car should be 425-440 rwhp? My Tuner says he's done all he can and that the hearsay numbers are BS.
I think my Tuner's LS engine knowledge is limited, he mostly does Mustangs, where he has a good reputation. No corvette Tuners exist in my area (that I know about) central PA. Can I remove the PCM and send it to a tuner that knows the set up that I have?
Should I be looking for mechanical problems (vacuum leaks, compression etc) that are hurting me.
Very open to suggestions. Stretch
I think my Tuner's LS engine knowledge is limited, he mostly does Mustangs, where he has a good reputation. No corvette Tuners exist in my area (that I know about) central PA. Can I remove the PCM and send it to a tuner that knows the set up that I have?
Should I be looking for mechanical problems (vacuum leaks, compression etc) that are hurting me.
Very open to suggestions. Stretch
Drifting
Joined: Oct 2009
Posts: 1,438
Likes: 4
From: Always in my lane.
2003 Z with Grantelli MAF, LS2, Fast 90mm, G5x3 cam, LT headers and 25K miles. Cam was installed by my Tuner who base lined the car at 390 max power and 372 maz torque. It appears a MTI -G cam was in the car (by others) and we put the G5x3 in. The Car had some minor idle issues before but was very driveable. After the cam install and 8 hours of tuning (per the Tuner) the car makes basically the same numbers and has "stumbling" idle issues as soon as I give it gas off the initial start up idle at 1K rpm. I've called and talked to LG and read numerous Forum threads that say the car should be 425-440 rwhp? My Tuner says he's done all he can and that the hearsay numbers are BS.
I think my Tuner's LS engine knowledge is limited, he mostly does Mustangs, where he has a good reputation. No corvette Tuners exist in my area (that I know about) central PA. Can I remove the PCM and send it to a tuner that knows the set up that I have?
Should I be looking for mechanical problems (vacuum leaks, compression etc) that are hurting me.
Very open to suggestions. Stretch
I think my Tuner's LS engine knowledge is limited, he mostly does Mustangs, where he has a good reputation. No corvette Tuners exist in my area (that I know about) central PA. Can I remove the PCM and send it to a tuner that knows the set up that I have?
Should I be looking for mechanical problems (vacuum leaks, compression etc) that are hurting me.
Very open to suggestions. Stretch
Melting Slicks
Joined: Jul 2010
Posts: 3,355
Likes: 113
From: Los Angeles
Yeah, this setup should easily make 420+ on most dynos. What type of dyno does your tuner use?
Thread Starter
Heel & Toe
Joined: Oct 2008
Posts: 19
Likes: 0
From: wellsville PA
Yes, LS2 TB.
I can change the MAF, still have the stock unit.
I read that the stock injectors are good up to 500 BHP.
Anyone else feel the stock injectors are not enought for this set up?
I can change the MAF, still have the stock unit.
I read that the stock injectors are good up to 500 BHP.
Anyone else feel the stock injectors are not enought for this set up?
Melting Slicks
Joined: Jul 2010
Posts: 3,355
Likes: 113
From: Los Angeles
What I actually meant, though, is that there could be an actual problem with your fuel system. I recently had to have my fuel pump wiring harness replaced because my Z was running rough at low rpm and would totally crap out at high rpm.
Thread Starter
Heel & Toe
Joined: Oct 2008
Posts: 19
Likes: 0
From: wellsville PA
Still working on it. The car's at a chev dealership to start from the beginning looking for issues. Ok on compression, valves and the cam install. They found some vacuum leaks from the fast intake and my air bridge. Also found a small hole drilled in the throttle plate of the LS2 TB, which was ported (by others). Not sure about that technology?? I checked a few "porting" sites and no one talks about, drilling the throttle plate. I feel the issue is the tune. I've been talking with a TX tuner to bench tune my PCM and he feels comfortable about being able to get the idle smooth and maybe recover the power that should be there. He familiar with my set up. I will be going back to the stock MAF.
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Thread Starter
Heel & Toe
Joined: Oct 2008
Posts: 19
Likes: 0
From: wellsville PA
I'm planning to re-work the air bridge and go back to OEM MAF. On the "drilled hole" in the throttle plate? I believe I have a much better tuner lined up now. Should I take the TB apart and get a machine shop weld it closed or will the heat warp the alum? Or, just let it there?
