So I love the added power of my GMS1. I had a couple of issues though.

1. Ordered the GMS1 from crate engine depot with the quick connects. Chevy dealership I took it to said the quick connects were wrong so they had to cut the heads off one side. My guesse is that they cut the connector first from the factory harenss and then realized they messed up since I had quick connects. Not the end of the world but oo well.

2. So first and second gear I get about 20-22 psi which tapers to about 17-19 at high rpms. I get this result in first and second gear. In thuird and fourth I get about 16 that bleeds down to about 12-13 at about 5k. Is this normal for an automatic?

Thank you,

Eric

 

Yes that's normal. Only way to keep high boost at high rpms safely is with another tune.

 

Yes, as above, this is normal. Dont be surprised to see those 20-22 numbers start to dwindle down over time. Sometimes I dont even get 20-22......sometimes I do......

 

My numbers have never went down with the GMS1, here is a video of my
GMS1 in action:

http://www.youtube.com/watch?v=79lfV...d8AUAAAAAAAGAA

When the trifecta is engaged...it'll hit 27 psi....no problem. BUT...I've been having some issues with my wastegate (I believe)...so I've been having some problems at part throttle as well.

 

So it sounds like everything is normal. I was just shocked that I only see 16 psi in third in fourth gear. That does not seem right to me.

 

Yes you are not going to get 22-23 PSI all the time under all conditions.

The Boost will vary under loads and conditions to help control driveability and to keep the car in on piece.

Temps, feet above sea level and ther factors come into play.

 

It all depeneds on the condition of the engine. You might lose a little with higher miles but not much. All engines lose a little umph with age and worn rings.

 

Seems like the GM version of any tune is always readjusting itself to stay at a certain level.

Kind of like the stock tune will adjust itself to be 260hp even if you turn up the boost manually. Sounds like the same situation happens with the GMS1.

 

This is something I don't understand about the GMS1 or whatever it's called.

I've gone through it all, had the connectors soldered twice, sealed twice, moved the intercooler up, put on a harder top engine mount and it seems this car has a mind of it's own.

Today, I hit the 10 in LA going east and it was mostly empty so I nailed it and the boost gauge went slightly past 25 pounds. I was at 105mph before I knew it. I slowed down, waited for traffic to clear then did it again, back over 25lbs and goes like crazy. Was grinning ear to ear.

Then stopped had lunch, ran some errands and back on an empty stretch of road, nailed it and you could feel the car go through this kind of off and on surging, like someone was running it from remote control. Power woiuld go up, then down then up and never go over 15 lbs.

Even my Impala SS does something as weird. Traction control on or off, if you nail it going around a corner or where the traction isn't perfect it just cuts the motor then grabs and takes off, then if there is spin cuts the motor again.

I've taken it in to the dealer three times, had everything checked and reflashed and always the same result.

Now, consequently, I have a Mitsubishi EVO that you can just drive the bawls off of and it always runs the same. No hesitation, no computer getting in the way, it just bloody flies and does it summer and winter, rain or shine.

Is this GM's way of saving the parts and the warranty or is it these cars just aren't thought out enough?

It's almost dangerous if you want to go fast quickly because I never know what the HHR SS or my Impala SS will do under any circumstance.

 

No the GM Tubo Upgrade will not adjust down.

The main issue I think involved is GM could only fit a older transaxle to this vehicle standard and Auto. The fact is they were made back when numbers like these were unheard of. To fit the 6 speed would have taken a redo of the floor and firewall that would require all new crash testing etc for a vehicle that was going out of production soon.

For the most the power is there when you want it. If you want full boost all the time take it to a tuner and save some money for a broken driveline.

You have to remember the SS was done when GM was hurting for money like there was no tomarrow. The new cars now all have the better tranny and will get even better stuff soon. You have not really seen much of what is coming yet. The base 2.5 4 cylinder will be 200 HP the Turbos are already at 270 HP and I expect 300 HP is not far off. I also expect a 400 pluse HP turbo V6 soon.

But the bottom line to the HHR SS weakness is the tranny. Torque managment is the name of the game for most of the cars that had the older tranny. Note my GTP was limited to 260 HP and the GTP also had limits due to the 4 speed auto. The new 6 speed auto is now in the Impala as they had the money to replace it and it now has a 300 HP V6 in it. It's not even an SS it is just the only V6 they offer.

The GTP guys used to convert their drag GTPs to the Cadillac tranny. It would take more but again they had to cust the floor and firewall to make it fit.

The cars are more thought out than most owners ever could imagine. That is why most do not understand what and why they do what they do. GM lifted power at shift points to protect the tranny. They also cut power if it builds too much from a stop.

The fact is the engine is just better than the tranny was. It is now out of production and no longer an issue. The 6 speed is sweet and in the new ATS Cadillac the 2.0 Turbo will really show what it really can do. GM also has a 7 speed coming too but I do not know if it will make it to this engine or is even needed.