Ok, so I have a SS 2.4 with the auto tranny
I already have a GMPP cold air intake and am wondering what would be my best choice for my next mod
Eibach Sportlines
Magnaflow Cat-Back
Header
what do you think guys?
help me out here!

 

i wouldn't replace the header just yet, its not too restrictive. if you want to do somethiing with your exhaust get a dp and a catback, or just a downpipe.

as for springs, sportlines aren't too bad. but i think people get them just cause everyone else has them and says they are so great. but there are quite a few choices for lowering springs

 

if you were going to suggest springs in that case which ones would they be?

 

well i actually would get the sportlines, but because thats the drop i'm looking for. but there are other springs with different drops and ride qualities out there. i'm pretty sure gravana caries some, and A Plus Performance, and TTR and OTTperformance. just look in my sig haha. the ottp link doesn't work so just go to ottperformance.com

 

Eibach sportlines

 

yeah i've heard amazing things about them
sounds like thats the way i will go when i get springs!

 

bump

 

go w/ a catback...

magnaflow is a lil to loud for my tast..check out the gmpp

 

yah definatly the GMPP i LOVE mine

but i would choose sportlines

 

thanks guys, is mangaflow really that much louder?

 

bump

 

header and downpipe. biggest restriction removed.

then get a good tune to tweak your timing, afr, and auto trans shifting

 

which would give me the best gain for $$
header or a cat-back
i'm also wondering which would allow the engine to rev quicker

 

neither will allow you to rev quicker. the only thing that will make your engine rev quicker is taking weight off the engine's rotating assembly.

the biggest restriction in our exhaust has proven to be the manifold/downpipe. That should net you slightly more than just a catback.

 

but the mass of the rotating assembly won't give me much if anything for HP correct?

 

rotating assembly = crank, rods, pistons. you arent lightening any of that on that LE5 engine. rotating parts that draw off the engine's power also include wheels, crank pulley, and flywheel. those are more commonly replaced.

and no it doesnt "give" you horsepower, but it would "free up" lost horsepower by not using as much to turn the assembly and giving it less inertia. thats why it can rev / down rev quicker.

 

thanks
that helps alot!

 

don't do a cat back just replace the muffler and the pipe from the rear axle back. Stock cat back is already 2.5 inch mandrel bent up to the rear axle. It narrows to 2.25 inch at the rear axle. Have a muffler shop cut the pipe there and replace with 2.5 in pipe at the rear axle and get a new muffler(any one as long as it's straight through. Get the header too. Pay less than you would for the whole cat back and get a better result. more bang for your buck. That's what I did.
If you still want the cat-back I wouldn't do the gmpp because it is 2.25 inch the whole way. What ever you do you want 2.5inch for your cat back(ex. magnaflow, megan, corsa, ark, or pacesetter if you want a cheap one)
In terms of springs, I have the ssc springs that zzp sells. I like them, they were a good value.

 

so you figure i would pick up some extra HP from just the muffler?

 

cant hurt, but its minimal gains. maybe like 5hp.

 

yeah catback is still the best IMO

 

I dropped 3 tenths from just a muffler in comparison to my car was running stock. Now maybe it was a better day or better conditions, but the runs were only a couple of weeks apart.

 

3 tenths thats awesome!!

 

bump if anyone is interested in giving more free advice

 

Get the springs, then people won't bother you with " drop it, it'll look better" line when you post pics of your car.

Also I suggest progress lowering springs, very nice ride, and low, or lower than sportlines. Also cheaper.