HS50 tuned exhaust length?


New Member
Interesting to know if any of you have played around with tuning the exhaust lengths for your Tec engines (in particular the HS50) and what other modifications you are running, mild or wild.

I'm building an HSSK50 engine ...
Modified ports and manifold
-.020" off the head
Tec carb usual mods like:- slimmed down butterfly shafts, cleaned up throat, throttle plate fully opens, etc.
BCR filled off the camshaft (might go Isky)
7/8" I.D open exhaust
Governor set at about 4,600rpm

Now I know tuning the exhaust length accurately entails dyno time and will be specific to certain mods in particular cam spec and rpm, but it would be nice just to get in the right ball park.

So if you guys have done any experimenting with exhaust lengths, or have a set up you favor it would be interesting to know.
ole4 has got it right.:thumbsup: On a minibike, the short length does not allow for much "tuning" of the exhaust. On race karts, however, they have more length to work with by making a "bugle" or "ram's horn". One thing that you CAN do though, and will improve performance is have your pipe properly "staged" (sequential and gradual increasing the I.D. of the pipe). Try for at least a 16" long pipe with 3-4 stages. We are running these on both our Raptor and H60 with good results.