H pipe vs. X pipe

[NetBSD]

so i have a 1980 gs450L with the H pipe, but i was thinking instead of replacing the stock pipes why not make up a set of new ones and make it an X pipe, would i gain or loose anything or wouldnt it make a differance?

the reason for this is the stock H pipe is starting to get pretty rotten where it rosses over and over the winter i plan on putting this thing in my lil shop and doing some work to it

[Mark M]

Well, the X-pipe is nothing but unsubstantiated hooey, so I wouldn't copy that. You are better off with a well done 4-1 or 4-2-1 pipe. Assuming your bike is a 4 cylinder, that is. A twin is good with a 2-1 or separate pipes all the way out.

Whether it gains or loses is entirely in the details, such as primary pipe diameter and length, collector design, tail pipe diameter and length and the muffler you use. No particular design is a magic bullet and all must be carefully designed and then optimized through testing if you hope to realize any sort of significant gain over stock.

Mark

[zig06]

X pipes work good on v8 (and v6) engines and ok on some 4 cylinder engines, if you need to maintain dual exhaust outlets. But you need to be willing to really rev it up. A better choice would be a 2 into 1.

[NetBSD]

ok now you guys are confusing me, the 450L is a twin and everywhere i read says to keep it 2 pipes into 2, not to runt hem seperate because yer gunna loose power, i understand aboput the x pipe on a v8, i had a 78 f150 i did that with and it gaind a few hoursies just nopt to sure on a bike. i guess i could just make a new center section outof stainless for my 450 if the x pipe wont help at all

[Mark M]

ok now you guys are confusing me, the 450L is a twin and everywhere i read says to keep it 2 pipes into 2, not to runt hem seperate because yer gunna loose power,

Well, a separate pipe for each cylinder is the optimum because you can tune that pipe only for the wave activity for that cylinder, it acts like two singles ganged together on a common crank. It is easiest to tune this way and I think it will make the most power (if anyone can prove otherwise, I would be interested to see the dyno results). There is a reason that Honda ran 6 pipes on their 250cc 6 cylinder GP bike in the sixties and why Ducati still use two pipes today.

Honestly, either way will be OK for your bike. It is not a highly strung racer and will make whatever power it makes with whatever you like if you design the primary pipes properly and use quality high flow mufflers.


Mark

[NetBSD]

a dyno test would be great, same bike same day test, one with a H pipe and one with it removed. this seems to start trouble with everyone i ask because everyone is saying different.

[82Shafty]

Why don't you just fab up a power chamber and blow everyones mind.