Littlemanhhr

I have a 07 hhr 2lt was wondering what would the best for horsepower gain and actually works. 20 to 30 extra horse would be nice.

GDZHHR

nitrous

I got ~35 hp with a 50 shot of nitrous and ~60 with a 75 shot

nitrous is easiest. there is no turbo kit yet.

I did gain about 15-20 with a tune.

TomsHHR

A Tune will help I get about 20 extra with my 2.4.

J W Davis

I have been reading all of the questions about hp gain, tune ups, mileage ect... and have learned a lot from this site. First of all, Thanks to everyone.
After 44k miles I realy can not complain about the power and mileage, have had no problems of any kind and still runs great.

I will tune up "Taz" because it will help him and that is part of being a do it yourself person. Any suggestions for best parts at a local level?
2008
1LT
2.4
Black with everything possible from factory.
Auto
K&N Air Filter

Black/ Dale Earnhardt "Taz" Special.
jwd

RaineMan

With any NA vehicle.

I/H/E and a retune will net you some nice numbers.

GRUMPEE

I/H/EWhat's that?

prod

Intake, header, exhaust im guessing.

RaineMan

Sorry... tuner speak.

I/H/E. Intake / Header / Exhaust.

Should really be the beginning of any automotive build. Reduce restriction and let the engine breathe better. This should gain you 10-15hp in a NA (naturally aspirated) vehicle. Then have the ECU retuned to take advantage of this extra airflow... which should net you another 10-15hp.

After that you get into more serious stuff... cams, port/polish the head, etc.

I stay away from nitrous... it can be dangerous if you aren't VERY careful, and I've seen some knowledgeable and experienced folks get hurt by it. Plus it is illegal to use on the street.

JoeR

I see LOTS of "ricer math" on this thread...

The 2.4 has excellent design on both the intake and exhaust. Very little, if any gains there.

As for any tunes.... Absolutely NO WAY that any tune will gain 20 HP!!

Best answer so far... Mike w/ nitrous!

Otherwise, you'll only get more noise (heck, good for some, but foolish to equate that to HP!!)

Don't be a sucker to aftermarket ads and their inflated or false claims!!

Marcruger

Hi JoeR, I serious question of you if I may? I can understand that a tune cannot produce the peak hp numbers they claim. However, with the factory delayed enrichment "5 second penalty", couldn't a tune improve power on the lower end of the band? If I am misunderstanding all of this, please forgive me. I would appreciate any input you could provide. It is not likely that I would do anything before my warrantee runs out anyway (only at 15k miles right now).

BTW, when supercharged, how well does the transmission on an HHR hold up? When rebuilding, are parts available to strengthen one of these transmissions?

Many thanks and God Bless, Marc