Hey guys, I have my GMPP exhaust sitting in my room right now waiting to go on. I was just thinking today... Would it be better to go buy a header/downpipe and put it on at the same time I put the exhaust on?
Also,

1 - Anyone know the average HP increase from doing header/downpipe/exhaust? I know there's no set amount but I was just wondering if anyone had an idea. I know the GMPP exhaust is supposed to be +10HP or something.

2 - Like I said I have the GMPP exhaust and I'm pretty sure I saw a GMPP header/downpipe somewhere, anyone have it?

3 - "GMP states that these headers have a 30 CFM Flow gain over the stock manifolds." <---What does that mean? (kind of a noob so don't kill me for asking a question haha)

 

yes, yes it would

 

Eh.. If you have the money i say go order a header/DP and do it all in one swift motion.

ZZP 1 3/4th Midlength/DP combo is amazing at 389.99

 

It is always easier to put on a header, downpipe, and exhaust at the time.

 

yeah much easier to remove everything and install all new ****.

 

Good luck with it being that low of a price exp if your getting a cat. Mine came out to 489.99 shipped

 

That's what I've been figuring. Christ now I gotta spend more money on it and the Stage 2 will definitely have to wait 'til summer now haha.

 

It depends on you mods but with you being stock, i would say maybe 5 hp

I think you should get a CAI first. You will fall in love with the sound ur s/c makes with it on there.

 

Yea, that's definitely the next step before the Stage 2. I was going to do it now, but I'd rather get all the exhaust stuff out of the way now instead of going back and re-doing things in a few months.

 

i think with full header,downpipe and catback 20hp is easily attainable if you already have stage 2. Stock i'd say are 10-15 at the crank.

 

Oh that 5 hp i said i was just talking about the cat-back only. my bad reading>me

 

bump.
Can anyone answer the 3 questions I had up top?

 

1. On a SS/SC prolly like 15whp

2. GMPP Manifold is a stock one dremeled/polished a little...a complete waste of funds...no downpipe from GM

3. It means that it flows a miniscule amount better than stock

 

With a full exhaust, you should see somewhere around 20whp if you have stage 2. Don't bother with the GMPP "header". Get a true header. CFM stands for Cubic Feet per Minute.



Edit: ^^^Basically what he said. lol

 

1. 10hp at the crank is realistic...not at the wheels.

2. GMPP makes the header. Same downpipe is used tho.

3. CFM = cubic feet per minute. GMPP manifolds are slightly bigger on the inside due to the fact that they are honed out, about 7% larger if i remember correctly...

good?

lol...3 posts at the same time...nice!

 

People show 10whp gains on the cat-back...

 

on a stock or stg2? perhaps i stand corrected.

 

Awesome guys, thanks for all the answers.

What header/downpipe would you guys recommend?

 

vibrant, zzp, pacesetter...if you can get the header/downpipe combo its usually a better deal...but those three are most used...check out the supporting vendors too...lots of good things on this site if you search...

 

Yea I'll be sure to check it out