Tune for LS7 in a Chevelle

[ChevelleZ06]

Please review my HP tuner scan. As per my name, I dropped an LS7 from a salvage C6 into a 1967 Chevelle. Over about one year, I have adjusted the fuel trims, had a bad cam sensor & the wrong MAF. I also have a C6 Z06 & my Chevelle does not run as smooth or strong. Both have long tube headers & 4" air filter.

The fuel trims were calibrated versus the MAF. The LTFT table shows 10% rich on the low end. How do I adjust for this?

Any other suggestions will be greatly appreciated.

[robbbc]

Can you elaborate on the not running smooth part? Is it a stock ls7? Are the rear o2's still active in the tune? I'll be honest, I dont really feel comfortable clicking on links on the internet so i have not looked at the tune. There is alot of knowledge on the HP tuners forum and suggest you check it out.

[ChevelleZ06]

Yes, I am posting on HP forum too. the low end acceleration is sluggish & the Z06 feels better. the LS7 is stock except for headers; stock heads. no rear O2s; no cats.

[chevelletiger]

Yes, I am posting on HP forum too. the low end acceleration is sluggish & the Z06 feels better. the LS7 is stock except for headers; stock heads. no rear O2s; no cats.

Have the heads been done on the LS7 in the chevelle?
Cam are know to get wiped out on the LS7 too,rod coating on the titanium, etc.
I also have an 09 z06.
I will say,even if the chevelle has the LS7 engine,imho,will never feel like the z06.

[shelteredchevelle]

There are a, few really good remote tuners out there, I use for my Chevelle, which is Holley. I used a really good HPT guy for my CTSV. Maybe that would help?

[robbbc]

Yes, I am posting on HP forum too. the low end acceleration is sluggish & the Z06 feels better. the LS7 is stock except for headers; stock heads. no rear O2s; no cats.

Not sure of your knowledge of how the ECM operates, but even if you physically have no rear o2 sensors, they can still be active in the tune. Unless you have already had the rear o2's disabled in the tune and the Catalyst test disabled, then you will continue to have some issues. I looked on the HPT forum but couldn't find the thread related to your car and set up. Post a log and copy of the tune on HPT website with the issues youre having and those guys will get you squared away.

[streetk14]

You didn’t mention how many miles were on the engine, but you could be dealing with mechanical issues. That or electrical issues related to your swap.

Do you have any codes showing up in the scanner? I try to only deactivate the absolutely necessary codes on my stuff, that way you get a CEL warning when something isn’t right. I’ve seen tune files with almost every DTC turned off. For what it’s worth, I don’t believe you can turn off the catalyst or rear 02 sensor tests with the current HP Tuners version. They must have gotten hit with a fine or threatened by the EPA.

Have you been logging knock retard? That’s one thing that comes to mind when you say it feels sluggish. If you have something rubbing somewhere you could be getting a boatload of false KR. I don’t think the fuel trims are a real issue at 10%. I’m not a pro tuner, but I’ve tuned my own junk for years. If you want to tune this yourself, you need a wideband 02 sensor. Otherwise you have no idea what fueling is doing at WOT. If it’s taking full spark, has the throttle wide open, and AFR is in the ballpark, it’s not likely a tuning problem.

If you want to have someone who really knows what their doing dial it in, I highly recommend Greg Huggins. The guy is incredibly experienced and thorough.

[streetk14]

I’ll also add that in comparing the performance to a C6Z, weight and gearing could be a factor. Those cars are 31xx lbs from what I remember.

[WUSTANG]

Greg Huggins ?? Is he on this site , I’m in need of a tuner myself TIA

[streetk14]

Greg Huggins ?? Is he on this site , I’m in need of a tuner myself TIA


He’s very active on the HP Tuners forums. That’s where I found him. I usually tune my own stuff, but I’ve been working with him to dial in the injection timing and a few other areas I’m not well versed in.

[email protected]

[robbbc]

+1 for Greg. Greg has helped me alot as well. 100% would recommend him. Streetk14, would you be willing to share your file for the ls7? I too have an ls7 in my Camaro.

[streetk14]

+1 for Greg. Greg has helped me alot as well. 100% would recommend him. Streetk14, would you be willing to share your file for the ls7? I too have an ls7 in my Camaro.

It has a cam, MSD manifold, and a couple other things, but I can send it to you if you want to PM me your email address.

[robbbc]

nice. I too have cam, msd, long tubes. i suspect your your sig. is still correct at 427/570 only, @ the wheel.

[streetk14]

That would be nice. No dyno time yet. I thought 525-550 whp with the mild cam it has. I know RPM does 625-650 whp LS7 builds all the time, so there’s definitely some room to grow if I want to port the heads and do a big cam.

[robbbc]

you're probably really close to that depending on what all you have done. I was told by a reputable tuner from HP Tuner forum that my combo should be roughly 560ish @ the wheel. I havent dyno'd my set up either so if it hits that number, then great, if not, im good with what it is. My heads have been milled .020, ported and have been "fixed" as i sport the OEM ls7 head.