SpaceCowboy

you must have a calibrated butt...because I'm not sure most people can detect a 2-3 hp gain. You are just probably feeling wallet/sound horsepower.

chefhhr

I must because it's a considerable difference upon acceleration. I think many people have mentioned after installing an aftermarket intake that there was a considerable drop in power under initial accerleration, but you can feel a little difference in the higher RPM range. I'm pretty sure this can be fixed with a tune though.

Also, if I felt wallet horsepower, wouldn't I feel more power with my expensive aftermarket intake? You must have read all that wrong...

SpaceCowboy

i don't know why people will state hp differences with nothing to back it up...no dyno numbers...no difference except in sound and how much money you have parted with

chefhhr

I don't know why people are bothered with the small things in life.

IMPALADAKID

I guess my real question is what performance parts that are out there that really work on the 2.4? I am trying to extract the power that is already there, not make more. 18 years with the 94-96 LT1 powered Impalas, and caprices have taught me that the corvette had 300 hp, while the Impalas only had 260 hp, but by replacing the intake and cat back with less restrictive ones, some headers, tune, and throttle body bypass, you could gain most of that 40 hp back. It is there just waiting to be extracted, but with restrictive intake, and small diameter tail pipes, the impala was having trouble trying to breath, and therefor hiding 40 hp.
And the throttle body bypass on the impala was tested on a dyno, before and after. It showed 7 hp gain bypassed at operational temp.

Snoopy

I guess if you are just speaking of bolt ons......

A good aftermarket air intake with an adequate filter
A different muffler
A de-catted down pipe (don't know what your emission restrictions are in NH)
A bigger "throttle body"
Premium gas
Tune after installing all the above


The tune is the key to "waking up" all the installed equipment. You probably COULD get the 25 HP you are looking for. But be aware, you are only talking about a 2.4 ltr. (something like 150 CI) that has had HP stretched by Chevy. Mostly everything that is on the car is near the extreme output. Except Chevy had to consider noise, mileage and emission restrictions.

Regarding your interest in part swaps from other 2.4 cars, there is none currently. In fact, GM is already considering a replacement engine in upcoming vehicles.....the new Malibu as a example.

The oil change is minimal if any at all. I've seen dyno tests that would suggest 1/2-1 HP.

Bigger injectors MAY help but with the engine mods suggested above, it doesn't warrant it.

Last thought, and I am not sure about this but, a couple 2.4 owners said a dyno test, after a total premium gas Trifecta tune, yielded 20 HP gain.

Good luck

Oh, and I forgot to ask....which engine do you have? Your post here asks about a 2.4 but your profile indicates a 2.2.

bassbase

Trifecta will get you between 15hp to 20hp gain at the wheels.

IMPALADAKID

That is why I am asking Snoopy. I know a lot of what it takes, I am really looking for which brand parts work, and which to stay away from. I have my own tuner, but I see Trifecta is very popular here, so I may give them a shot.

I need to update my profile. The new HHR is a 2.4, and my old one was a 2.2

Really? That seems like a big jump as a stand alone mod. At the very least, it must be a 93 octane tune.

PaperChaseHHR

ive been doing a little research on which CAI to purchase and i believe with this PROOF chefhhr is right. sometimes they do make enough of a differnce you can feel. especially if you know about how long it should take to get to say 60mph etc. and an 8hp/8tq gain id imagine you could notice a difference, this is what ive found.

hhrfreek

KN, GMPP intakes
Badmab header
GM LSJ header
ZZP downpipe
GM LSJ dp
LSJ throttle body(from SC cobalt/GM part, requires adapter/harness)

Also the stock intake manifold tapers down right at the end of the runners(a lip on the end) and is about 2mm smaller than the head ports.