I am sure the tune is down in 1st and 2nd gear.

If it won't handle it now it won't with more.

The 4 speed tranny is the only one that fits this and they had not other options. The six speed will deal with it but it won't fit in the HHR.

Over time they could either modifiy the HHR pan or beef up the 4 speed. niether is a cheap change so I would not hold my breath. till a platform change.

 

Has anyone compared the differences between the Hahn tune and GM's other than factory warranty? Is either one better than the other?

 

I can tell you,when you hit the gas the turbo is there from the get go...there is NO hesitation.Its hits 18 then drops back ..puttering along at 30 and drop the gas it does the same ,it drops gear and rips tires.All I can tell you is,you want to know,,get one! The only thing it can't handle is keeping the tires hooked up. This kit wasn't made for the average grocery getter,if one installs it one knows what the results will be.

 

What is the affect on MPG?

 

So far I have not seen any difference in MPG using the GM tune

 

That's great news. Now if I can find a few hundred bucks laying around I might go for the tune!

 

After having the tune installed for about a week I see a difference. Driving 50 miles a day, mostly hwy, the numbers are slowly dropping. I'm going to take the positive side of this and say, that as soon as the newness of all this awsome power wears off, I'll be back to an average of 28 again. I think it takes a few weeks (or months) to wear off. But I could be wrong and the tune degrades your mileage. " I dont think so Tim".

 

Like NIKE said, Just Do It

 

Like my wife says:"I don't think so, Tim"

 

just control your right foot, that controls MPG