The GM Upgrade is two 3 bar Maps (2.7 bar stock I believe) and a GM tune on the ECU. Wouldn't any aftermarket tune just over-write the GM tune? The net result would be an after market tune with a little more head room on the map sensor which is kind of unecessary at 21 PSIG of boost. I wouldn't mind just getting the GM upgrade but finding a dealer to trust with the install is difficult. What happen to the dealers interest in "GM Performance"?

 

I am not sure what your point is. The upgrade is fully warrantied by GM for 5yr/100k. If you add a non-GM tune on top and have a failure, they will find out (easily) and they might block your warranty. No doubt the 3 bar maps add some room for tuning but you can get those and the connectors on line for about $150. Then you can go with your preferred tune.

Any dealer can install the upgrade and the issues are well known and easily fixed if they occur. The dealer is responsible for installing the kit correctly and if they don't they have to fix it. It's not all that cosmic anyway - just a bit of effort on the lower map (room to work.)

I have the upgrade and find it's right at the limit of traction in 3rd (way over in first and second.) If you want more than that, you can decide what the value of your warranty is. You may never have an issue and be quite happy.

 

My point was that some members would give you the impression that an after market tune "over" (in addition to) their GM upgrade is much better than the after market tune alone. It would seem to me that the after market tune just erased their GM tune.

I live in central VA where the dealers aren't even aware of the turbo upgrade. I've read of enough problems that members have had with their upgrades installed by less experienced dealers. My son lives in Charleston, SC so I might take it down their to the Hendricks Chevy dealer for the install.

 

I have a custom HPTune on top of m stage kit and i did it because you have more room for tuning, can push more boost (safely) and when i go bigger turbo ill be all set. It all depends on what you wanna do. With my tune my boost tips in at 26psi and settles at 24psi

 

Ah, I see what you mean. Part of the issue is that much of the upgrade changes aren't in HPT or the other editors. So to use the 3 bar maps you need to start with the upgrade operating system and then you can change things. Otherwise you are stuck with the 2.7 bar maps and are somewhat limited.

I dunno. Do I really need to disintegrate the tires when I can already burn them to charcoal? I guess you can never have too much power!

 

I bought HPTuners Pro about a week ago and BYT from the cobalt forums did my tune. All I can say is I couldn't be happier. I have an auto and at 40 mph, if I lay into it, it will ROAST the tires! I paid 645 for the HPTuner and 100 to BYT and I'll have unlimited possibilities for upgrades in the future...plus I can use it on my other cars. I'm pretty sure you can get away with the regular vcm suite HPT and it's even cheaper. I bought the pro so I can use it with all my cars.

 

Just saw this on the gto forum, damn good price.
http://www.ls1gto.com/forums/showthr...=1#post6754410

 

BYT knows his ****, ur in good hands

 

Watch for heat in the cylinders with any tune.

 

Thinking about getting HPTuners but not much help on their forum about HHR SS with auto trans. Also it seems that the boost numbers I see quoted on both forums (ours and theirs) are not that much better than with GMTU. Is it worth it?