Header Performance?

[salty_monk]

Seemed to improve power across the rev range on my 1000G.

I never rode with a stock airbox on the Skunk but it's sister bike was ridden that way by Robertob & then upgrade to pods & pipe & he was very impressed with the difference...

http://gs1000e.blogspot.com/

Dan

 

[not a biker]

on the kawa ZRX 1200r i had a slip on muffler beat a full system up to about 7,000 rpm, from 7,000 to 9,200 a slip on and full system tied. at 9,200 up to red line the full system made 3 more HP. what a lot of folks do not understand is a stock system will outperform a racing pipe in all but full throttle high RPM conditions.
so if you are ricky racer and just run the pu out of your bike the full system is the way to go. if you putt putt around town and you almost never red line the engine a stock system is good enough. header companies do not want you to know that the HP gains they tell you about are peak HP numbers only.

 

[80GS1000]

Header design comes into play too. Modern sportbikes all run 4-2-1 headers as they make more midrange power and have more ground clearance than 4-1 pipes. That said, most modern stock pipes are swapped out for just weight savings and cosmetics - the stockers flow pretty damn well.

On a GS pods + 4-1 pipe + jet kit makes a noticable difference on the butt dyno, if nothing else than 25 pounds of weight savings and a few extra ponies.

 

[jabberjoe87]

i think every bike will vary because of different types of carbs and what not, some carbs run like crap with pods on them, the throttle slider carbs found in my bike 77 750 work well with pods. If you think about it, when does just putting headers on anything build hp? For there to ever be more hp built, there needs to be that perfect balance of the air to fuel. Just because bigger jets are in doesnt meen its going to be faster, it might just run really rich. Just headers might make it too lean. Who knows i dont i jetted my bike with pods and exhaust and i think it definatly has improved, but the expectaions are always really hi so it may seem that its slower because its way louder, or something like that.

 

[Mark M]

10% seems pretty optimistic based on the 2% gain shown in Minton's test. Don't want to put people down since experiences vary, but I'd love to see some published information showing such gains are possible.

I already mentioned my 82 1100E, here is the dyno chart from the PO. The bike is stock besides the Kerker 4-1 and the modified airbox I mentioned.

I have since replaced the airbox with pods, jetted and degreed the stock cams to the stock lobe centers. It is now noticeably stronger than when I bought it. I expect it would run around 104-105hp if I tested it now. This chart was done at around 3500ft elevation and does not have an altitude correction factor applied that I know of. The flat spot shown in the chart is gone now, after I finished my jetting for the pods. It still has a dip in torque, but no where near as pronounced. With the big engine it is unnoticeable on the street.

Unless you believe that the low 90's stock HP numbers published in many places, including the above Supertrapp test, are all BS (and done usually at sea level no less), then my bike shows a minimum 10% gain over stock.

This is why I said the pipe does nothing by itself, but the combination of pipe and pods does a lot. Our bikes were quite restricted to meet noise and emission regs and opening up both the intake and exhaust is very worthwhile.

Mark