So weird, because on every performance car I’ve seen, the headers add like 10/12hp and 8ft/lbs. Maybe it’s because they have those honkin’ cat converters in the stock ones. *shrug*
Alt, a couple of things, was that h-power claim from an actual dyno test or just a manufacturers claims to sell product ?
On automotive exhaust they are typically waaaay more restrictive than a motorcycle, mostly due to the exhaust manifolds themselves which is caused by simply packaging trying to make things fit and nothing more. Bikes really don’t have the same issues and 99% of the dyno testing I’ve seen the stock bike exhaust is better than the aftermarket. Performance gains in the aftermarket exhaust is simply due to being much lighter, typically 50% or more lighter. Also a lot of the claimed gains is by the increased noise levels (Harley factor) if it’s louder it has to be faster, right ? Also the “butt” dyno is a big liar ! Not at all accurate.
Catalytic converters, claims of big power gains there are quite simply pure internet myth, it ain’t there, past the early GM pellet type converter the current honey comb brick type simply is not a restriction, the pipe diameter creates more of a restriction than the converter.
An example I’ll give is that I have a 94 Dakota that I used to drag race and all the internet “expert” gear heads convinced me that there was an easy 25rwhp by removing the stock 2.5” cat so I fashioned up a straight through test pipe and removed the cat, it produced not 1 mores-power, zero, nada, nothing ! It used a lot more fuel (screwed with the O2 sensor a little) which made it slower in 60 ft.
I called an aftermarket performance cat company to talk to them (MorFlow) about the results, the head guy there just laughed, he said he sells a lot of converters because the mistaken belief is that there’s this huge restriction and he told me that past the oe GM pellet type (highly restrictive) the new honey comb converters literally provide zero restriction and that the pipe diameter creates more restriction than the converter. I did reinstall a converter on my dakota with zero negative results. Quite frankly there is very little to no benefit gained by removing any of the “emissions” equipment on a vehicle these days, it just ain’t there, as I say, “pure internet bs” nothing more.
Now all that said, I have learned that quite frankly there’s very little to be gained in the fjr past improving the sound and removing a little weight, maybe,,, ,,,, ride more, worry less,,, just enjoy what you have ! If you need more speed, buy an R1! My .02