GMPP Shorty Picture

[UsedTaHaveA68]

Meant to do this a month ago. Just in case anyone has been wanting to see what they look like, they're the bottom picture. From HOT ROD magazine.

And a pic of DT shorties for comparison


JBA shorties:


Borla, which I'm assuming is still in progress

[Nxtr]

From the looks of it, I may be wrong, but is it Borla that is doing the GMPP Shorties as well?

V/R,
Nick

[Edrock]

Originally Posted by Nxtr

From the looks of it, I may be wrong, but is it Borla that is doing the GMPP Shorties as well?

V/R,
Nick

Looks like it to me...I would have to agree.

[radz28]

You know - I can't see why it seems the DTs have gotten better results than what Hot Rod reported, even with the AB. I know I haven't seen but one (maybe two) results for the DTs, but it just looks like the primiaries are just a touch longer on the GMPPs and the collectors just seem to flow together better. I like that they're at least stainless (what, 409 was it?) and would like to see better comparisons for these and the DTs.

I wonder what the Borlas are going to look like...

[FTI-EDC]

/flame suit on

Why bother?

[radz28]

Originally Posted by FTI-EDC

/flame suit on

Why bother?

Because if you live in California, like me, and have spent $500 in fines for running long tubes, not to mention all the other sh*t I had to replace in order to swap the manifolds/shorties back on, a person might be inclined to find as much as of the potential power as the law and police enforcement allows; that is why. Let's get back on topic...

I think GMPPP makes those shorties, for sure, now that I've seen that illustration on Borla's website. I wonder what size the primaries are. I hope they aren't tiny 1 5/8" ones. Maybe larger primaries wouldn't matter on such short tubes :(

[FTI-EDC]

So... how much delta in power are the stock manifolds versus these shorty headers when coupled with the same aftermarket exhaust system? Especially with emissions requirements etc...

Got some dyno or track proof?

[radz28]

Well, there's a post in this forum where a member gained something like 16 RWHP with the DTs, and about double the torque, or something like that. The GMPP shorties, combined with the GMPP AB combined for like 9 RWHP on top of a GMPP CAI and a tune. Personally, I have nothing except these tests that were posted here and in the publication. If you search, you can find that DT thread.

[99-LS1-SS]

I thought the cats were the restriction on this platform? Am I wrong?

[radz28]

I'm sure the manifolds are at least equal to the cats', in terms of restriction. If there weren't four cats', it probably wouldn't be as bad, but alas. When you compare adding a set of NOWEEDS to a manifold/catd' car, it's suprising to see how much the gains are. It's almost more worth it, based of the numbers I've seen, to do that than go with shorties. You gotta' run with the cutouts open for that power though and cops in my area don't like that. I don't really blame 'em.

[FTI-EDC]

Originally Posted by radz282003

Well, there's a post in this forum where a member gained something like 16 RWHP with the DTs, and about double the torque, or something like that. The GMPP shorties, combined with the GMPP AB combined for like 9 RWHP on top of a GMPP CAI and a tune. Personally, I have nothing except these tests that were posted here and in the publication. If you search, you can find that DT thread.

So for the cost of the shorty headers versus keeping the stock manifolds is not really justified. Sure appears that a better exhaust system and high flow cats be a better investment for power and emissions compliance. That fits right in with what the GTO market has seen.

[radz28]

Originally Posted by FTI-EDC

So for the cost of the shorty headers versus keeping the stock manifolds is not really justified. Sure appears that a better exhaust system and high flow cats be a better investment for power and emissions compliance. That fits right in with what the GTO market has seen.

Yes and no, IMO. I can't very well run around with open cutouts, since I didn't even include the $150 fine I got for that already; so in some circumstances, cutouts (even having them on the car is illegal here...) are a better choice. The problem with high-flow cats' is that if they aren't CARB-certified, they aren't legal and a person won't pass smog if the inspector or referree sees them. After the cats', there's not much of a problem with exhaust mods' here, but before, unless there are CARB numbers, you have to either know someone, or you have to be lucky. California is a completely different animal. You can get away with this stuff if you're lucky and don't live in an area where the law is looking for you, but if not, you either leave it alone, or look for CARB parts that won't give you as much power :(