bigjacksauto

thanks Xtreme
I hope everything goes well I have a great service advisor and he knows how picky I am

bigjacksauto

I talked to the service writer and he said the tech said everything went very smoothly.
I asked him how the power difference was and he said he felt that I should be the first to try it.
It was a long day for me so I only got a chance to try a half throttle 10-40 mph pull.
the boost went up and was there almost immediatly.
Then from a 5 mph roll I tried another 1/2 - 3/4 throttlle start the car pulled way harder than ever before and it literally felt like it was clawing at the road spinning both tires but biting at the same time.
I was a bit skeptical up until then when I said "wow I guess it really does make way more power"
It was about 90 today with a ton of humidity drove it for about a half an hour ran into the bank and had to leave the a/c on for the family came out engine was around 215
which I have seen before but after a couple minute drive to the next stop.The fan kept running after I shut the car off.never had that happen before but then again never left it run at idle in this crazy heat and humidity we have.
after about I think two minutes I started it up for a few seconds to circulate the coolant shut it off and the fan went off.
After reading everything here this appears to be normal???????????
I am amazed at just with say a 1/8th throttle the boost starts to come up now.
I would Highly suggest anyone who is looking to have the GMTU installed in the Central NY area go to Burdick Chevrolet in Cicero NY.They where great to deal with and listened to every thing I had to say and answered all questions.

bigjacksauto

Does the GMTU modify when and how long the coolant fan stays on?
Another words I would assume they make it come on earlier and stay on longer?
I cannot wait to try it getting on the highway for example
It really is a totally different car now you just lean on the gas a little bit boost comes right up and it moves.
Thanks again everyone for all of your help and info on this.

rlee63a4

foolmoon, Can you share those tips about flashing for the brake fix? I don't seem to have nearly the boost I had before the brake fix. More than stock, but less than I remember. Thanks.

bigjacksauto

Foolmoon
I would also be looking for Any tsb to due with the brakes.
This new gmtu is great but I do not believe my recently added
Vacuum pump for the brakes is working.
This morning when I backed out of my driveway it felt like it did before I had tje vacuum pump added on.
there was a specific reflash for tje gmtu with assist so not sure whey happened

XtremeSS

There is numerous GMTU "tunes". They differ by year, tranny, and with or without brake pump. They must have flashed the file that is w/o brake pump.

bigjacksauto

That's what I was thinking.
Been watching the temp gauge got up to 205 this morning then would go back and forth to 199
Went into a store first 30 minutes came back out and there was a about a quart of antifreeze that almost gave me a heart attack to see what appeared to come from my car.
Could. Not see anything dripping though.
Immediately went back to Chevy dealer.
Parked on there white floor nothing at all came out.
Service writer said I could wait about an hour
But he pretty much said there is no way it came from my car.
Drove around for a while came home fluid level looks good thank God and absolutely no sign of fluid ever leaking out.
I checked very thoroughly.
Not sure where the fluid would come out of the overflow other than the pinhole in the top.
Anyone got a picture of an overflow out of the car where you could see an outlet?
Also the car makes awesome power 22 plus pounds of boost.
Goes grate from a 10 MPH roll spinning also.
But if I try to take off from a light and ease into it and try and get some traction when I finally put it to the floor boost goes to 22 for a second or two then drops to zero then back up
Crate engine depot said could be wiring pinching but it looks like the tech did a great job .
Ced also said could be a leaking Turbo? Any ideas?

SS fan

Yep, still have the grin, but I cheated and added Trifecta,

XtremeSS

Only have a few answers for ya on the boost fall/rise.
1. Torque management-normal with lots of traction from a dig or a very slow roll try turning esc off to see if it helps at all.
2. you may be spinning and not know it? If that were the case you would see "low traction" on the DIC, and traction control will reduce eng pwr
3. BPV may not be seating correctly with the abrupt psi, unlikely but possible. Stiffer spring would help this
4. The wiring harness on the lower MAP sensor may be hitting the AC compressor-most common of course. A great way to test this is to put a glob of grease on the MAP sensors pigtail and drive the car the same way you mentioned. See if the grease transfers to the AC comp. document all this with pics and if the wires are hitting then I would take it back to the dealer and tell them that you supplied that info pre-install for a reason.
This is a GMPD design flaw and should be addressed as such. IMO the HHR should of had a special kit that came with a bracket. If gm has to pay for the tech to make a bracket then so be it. SSfan showed the pic in previouse posts. I have seen him post that pic about 58 times (he's pretty proud of it) That is pretty simple to fab up.
End rant.
Hope this helps.

bigjacksauto

thanks
for the info I have tried it with the esc off the car spins the tires boost comes up quick then just falls off then right back up again
They did install a really nice bracket so good it looks like it came with the kit.
tons of clearance.
the grease idea is a great one.may have to try it.
still all and all I am very happy with the install that boost is amazing how quick it comes up.