When I got my XR8, it only had a genie 2 1/2 system, k&n and standard headers. It dynoed 105rwkw. After the genie extractors (exactly the same as the pacemakers) it dynoed 117rwkw, no other mods. The power improvement is throughout the rev range not just at peak rpm. The standard headers are the worst design I have ever seen. The primaries are so crushed, you can't even fit your small finger through some of the ports. You won't regret getting them, it's money well spent.
Thanks EDXR8, that info helped heaps. Its pretty much confirmed my decision to get them. It sounds like my car isn't far off your specs as it stands! At least I know I'm not alone in doing this stuff!
105rwkw - 117rwkw is a pretty good upgrade! And yes, I do agree that the standard headers a poorly designed!
As for the cats, well that just depends on the cash flow situation.
Have you put hi-flow cats on your car? Is there much of a increase difference in noticable power?
I actually did the extractors and cats at the same time. From memory, the standard cats have only a 1 3/4 inch (or something real small) inlet pipe. I went for twin 2 1/4 inch cats to match up with the extractors, but I have just upgraded again to twin 3" cats into a single 3" system to match my new engine.
I went from stock to k&n filter, coby headers, coby 2.5 inch exhaust, and threw the cats away, in one weekend. I was totally amazed at the difference in my manual EB V8 ghia. As you guys say, the standard headers are crap.
P.S I don't think cats are compulsory in NZ. Notice a lot of exhaust fumes without them though.
Manual EB V8 Fairmont Ghia
Headers, 2.5 inch exhaust, filter, lowered, 17 inch wheels, blah, blah
Hack = BMW m325i (Manual of course)
(OK, it's a 1987 model)
I wouldn't say high flow cats were essential, but should be up there on the list. From memory, the stock cats are well under 2" in diameter, which means, your extractors will exit with twin 2 1/4" and then reduce to twin 1 3/4" and then join to singlw 2 1/2". It will probably cost you a couple of kw, but if you are short on money, do the extractors and then wait and do the cats later (before any other mods at least).
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.