thanks. have that harness. Going to install the tmaps myself and harness but didn't buy gm whole kit so trying to find where to get a tune where i can run this setup.

 

A tuner might tell you something different, but it is my understanding that the gm 3 bar sensors won't work without the gm tune as a base.

I'm told that even though some tunes with the 2 bar sensors will equal the gm upgrade, they don't usually surpass it and the best process is

1. the 3 bar sensors and gm upgrade.

2. If you plan on it, do all physical mods next, like exhaust, intake, ic changes etc.

3. Hire a custom HP tuner to tune the car to your specs.

Word of caution.

The auto transmissions on these cars can be a weak link if abused.

The torque management is suppose to protect the transmission, but in my case came in so abruptly that it was like an on off switch that I assume damaged the transmission because on a run to Vegas from LA, my transmission essentially melted. Got it into Vegas and the chevy dealer findlay replaced it under warranty. BTW: theyre a great, great dealer and if I was buying a new Chevy I'd fly there just for their service, they are that good.

So bottom line is I think the torque management should be raised so you get wheel spin rather than that abrupt on off stuff that goes on.

Before going HP tuners, I tried to get Vince to address this, but said he could't do it on an 08, as he only had an 09 for experience, so I went with HP.

IMO

P.S. Obviously these little engines can produce a lot of power and after the cobalt/hhr ss, for the turbo ecotech GM limited the power on these engines. My HHR is suppose to have 290 crank power with the gm tune, my regal gs has 270 or something like that and very agressive torque management. On the Regal GS, you only get a chrip of the front tires coming off hard, on the HHR, you can light them up, though once rolling the GS has a much more sophisticated computer and the whole package is much more refined in drivability. It runs just like my bmw 325I and feels like a medium powered 6 rather than a on and off 4 cyl.

BTW: I have a lot of cars, but love driving the HHR SS. I actually would rather drive it than the regal gs, even though it's not as modern. I did do one other addition that made a huge difference for the passanger as I just had a grab handle from an impala installed by a custom interior shop. It was expensive, and had to be well thought out to clear the side curtain airbags, but it looks exactly factory done and my wife loves it.

Of course it wouldn't be needed if I didn't drive like I do.

P.S. 2 I think the HHR SS is a great tourer not a great stop light dragster. I find it interesting that it never seems to slam me back into the seat like other cars I have, but It's very deceptive in the way it feels, probably because of the suspension tuning. Even driving in congested socal, I'm always at 90 to 95 mph without thinking. 90 mph in these cars feels like 60, in comparison I also had a mistu evo 8 for 7 years which I rarely drove as it was so rough and sold it with under 19,000 miles. Great car, but going 80 mph in it felt like 120 and when the tubro kicked in it pushed you back into the seat hard.

The upside of the EVO was all the plumbing and parts were heavy industrial grade. No plastic anywhere and I could drive the living hell out of the car without worrying about anything breaking.

Still the HHR SS is a good car, could have been great if GM wasn't in such financial straights when they built it.

Anyway, if I really wanted to make the car much faster, I'd send it to ZZP and let them do all the work as they seem to be the leader in cobalts and this platform. They can beef up the trans, turbo, custom tune and replace most of the weak parts.

Other than that, I'd just enjoy for what it is.

 

hmm...interesting I never heard that before will have to look into it.

 

Like all tunes, the gmtu is synced to your vin number and unless you are or know a hacker, I'd assume it will always be that way.

Honestly, since I've tried them all, I'd go with the gmtu by the dealer as long as you have the harness so they don't have to strip wires and remember about that bottom sensor.

They say you can't turn it around because the inlet has this little naca duct triangle that turning it makes it go the wrong way, but it did wonders for my car.

Only after the gmtu upgrade would I consider any tuner, but that's just me.

IMO

 

Tune is in and what a difference ! It is like a completely different and better vehicle. I would like to thank CJ for his help in making this as smooth as possible.

 

Maybe I should hire CJ to tune mine ....Vince tried 9 times it still sucks.

 

The canned tune is a one time thing, take it or leave it. The full tune will still end up going through Vince for adjustments.

 

I moved from trifect to HP tuners, bought the suite and had James Haggerman do it by e-mail.

Sent in the stock tune, gave him a list of what I wanted, and on the second tune it's great and we haven't data logged it yet.

Right now it pulls like jack the bear compared to the gmtu tune and the trifecta.

He tightened up the shifts, it pulls hard and save to 24 lbs and just pulls and pulls and pulls.

It's gone for a reasonably quick car to a fast car.

Can't wait to data log it to get it exactly fine tuned.

I wish I'd gone this direction a long time ago.

 

question for you guys, what are you running for intakes? Ive been around here for a bit, still dont have a HHR but have a cobalt and have modded and tuned a 08 SS TC (not tuned myself but brought it to a local HPT guy) Looking to buy a hhr ss soon.

Question is, if your trying to get that good intake/bpv sound, how does the stock box with lid removed work after the car is tuned? Is ZZP intake a waste if so? I wouldn't want a closed box intake like K&N

 

I did a Superchips tune and have had NO problems and runs great. I didn't want to go crazy anyway so this is working for me. Feels as good as a GM tune to me.