GMS1 Issues
#21
Some have problems and some think they are to see 23 PSI all the time anywhere.
Just depends on what the issue or expectation is.
Many read here and often state they have boost issues when they really just don't understand. While these guys may have issues others don't and just don't understand what is normal in this car.
Just depends on what the issue or expectation is.
Many read here and often state they have boost issues when they really just don't understand. While these guys may have issues others don't and just don't understand what is normal in this car.
#23
So just to clarify. From a stop mash teh throttle. 22-23 psi through first second and then once in third I only get about 15 psi. So what you are saying is that this is torque management? If that is the case GM has been advertising false information because there is no way @ 15psi that the car is making the 290hp as claimed. I highly doubt you are only to get the full HP out of 1st and 2nd gear.
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
#24
So just to clarify. From a stop mash teh throttle. 22-23 psi through first second and then once in third I only get about 15 psi. So what you are saying is that this is torque management? If that is the case GM has been advertising false information because there is no way @ 15psi that the car is making the 290hp as claimed. I highly doubt you are only to get the full HP out of 1st and 2nd gear.
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
I don't believe with the GMTU you should ever be below 17 psi even with most things weather related considered.
#25
I have an 08 Auto which is HPTuned right now. It's very fast but still working on the tune esp the shift points. Because of the lack of other Auto owners it is hard to get tuning help but I am making progress. As for with the GMS1 I seem to remember 20-26 in all gears but I could be misremembering (is that a word?). I re-loaded the GMS1 (GMTU, same thing correct name) recently to check on some tuning issues and got between 17 and 22 in all gears. It's winter here so heat soak is not a problem right now but my earlier stated numbers are from the summer.
I don't believe with the GMTU you should ever be below 17 psi even with most things weather related considered.
I don't believe with the GMTU you should ever be below 17 psi even with most things weather related considered.
Thank you very much!
Eric
#26
So just to clarify. From a stop mash teh throttle. 22-23 psi through first second and then once in third I only get about 15 psi. So what you are saying is that this is torque management? If that is the case GM has been advertising false information because there is no way @ 15psi that the car is making the 290hp as claimed. I highly doubt you are only to get the full HP out of 1st and 2nd gear.
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
So if I ran this thing on the dyno right now they would dyno it in fourth gear. That would be at 15 psi. I would not get the claimed HP.
Who else has an Auto HHR with GMS1. What are you seeing for boost in 3rd and fourth?
Thanks,
ERic
When the GM tune is stable, my auto HHR SS pulls a constant 20 to 22 psi (from the pillar gauge) virtually at sea level and with 91 octane petrol through the first three gears up to 105 mph, then going to 4th gear it drops.
When it's not stable it goes from 15 to 27 psi but most of all surges and moves around, doing this it doesn't throw a code, but it will go into limp mode. I takes a restart to get it back to boost.
FYI, this week I ordered a complete wiring harness and the crate engine depot connectors to get rid of the in stability which I think comes from the splicing of the connections, even though they've been soldered and sealed twice.
FYI 2, I also have data logged the car and am having a third party review the results.
Don't be mislead from people that say if you expect the car to pull strong and stable your expecting too much, or that no manufacturer was ready for 300 hp 4 cylinders. Mitsubishi , Subaru, Volvo, and a lot more have made 275 to 300 hp turbo 4's and 5's for a long time that pull strong and reliably.
After talking to a lot of people that know these cars, the issue seems to come from an overly sensitive computer program that protects the drivetrain, shift changes and of course the 100,000 mile warranty.
If your car was stable in stock form (mine was) and then you go to the GM tune, you'll find that any changes can upset the balance, even changing an air filter.
Though nobody is running a score card and no manufacturer is going to give you details on how many specific problems they have, I do know that out of the 6 dealers I've contacted about this, three absolutely will not work on the stage 1 tune going back to when I first bought the car.
Obviously they knew something I didn't.
FYI 3. It seems the most problems with the GM upgrade is the splicing of the wires. Cobalts or HHR's it makes no difference, many have problems and the rule of thumb seems to be if your connectors are spliced and don't have a problem today, you will tomorrow.
FYI 4. My car at stock pulled steady at 15 psi, so if 17 psi is the standard of the upgrade (it's not), then who would pay nearly $1,000 for a 2 psi upgrade?
IMO
#27
FYI, this week I ordered a complete wiring harness and the crate engine depot connectors to get rid of the in stability which I think comes from the splicing of the connections, even though they've been soldered and sealed twice.
#28
Well folks, I had the GMTU installed this past week with the new plug and play wire harness' (no splicing). Was 14lbs boost stock. Now it's 17lbs. Tech said everything was fine. Was expecting more boost,but guess I was wrong.
#30
Same here. I rarely see 20lbs and when I do its usually at about 50 mph in 3rd after I drop the clutch.