ok i am no expert but i was thinking if we added the K&n intake (when availble) headers, hiflo cat, and perfomance muffler i would say thier should be a gain somewhere around 15-25 hp (i could be wrong) but let just say.

that means if your already pushing 177hp you could go up to 202hp if you get 25hp by upgradeing your entire exhaust system. that would br GREAT!!!

now take that and add the supercharger which on avarage will boost you 50% of your HP so you could be pushing 300hp

now if we add the turbo insted of the supercharger well i dont even have a clue but one of you out there does so please throw in your 2cents.


once again i am no expert just playing with figures. if you are better with this engine performance figs please enlightin us.

I think you would lose power if you redid the whole exhaust system without a turbo or supercharger. You wouldn't have enough back pressure. I experienced it on my Mustang. At first I redid the exhaust without doing the headers because all I had was a CAI. Later on I cracked one of the headers so I upgraded to some better flowing aftermarkets. I lost power sort of. I was very noticeable on take off. I lost power down low but seemed to gain power when I opened it up on the highway. You can't just stick on a bigger exhaust and expect to gain power, its usualy the opposite. If your only going with a CAI go with a cat back, if your going turbo you have to replace the exhaust because your turbo is integrated into the exhaust system, if your going supercharger do the whole set up header back. Also a 50% boost out of a supercharger is way optimimtic unless you are pushing a lot of boost out of it which would only be good for the track and not the street and you would run a higher risk of blowing your engine.

If i can get to 200hp I'll be happy. If I go beyond that I'll just want to go farther and father

btw has anyone put aftermarket exhaust on their hhr yet?

I test drove an HHR in Arlington that the dealer had customized with an exhaust sytem. By exhaust sytem, I think they really meant muffler. They said it was load when you want it to be, and then quiet at highway speed. I agree with those comments, but couldn't really tell about a power difference since I don't own one yet. Maybe the person who has that custom orange one in Arlingon will see this and give us a clue.