Will 15cc Domes Hurt Me

[slapaho]

i was told with 15cc domes i wouldnt have any topend without a port job is that true

[bkabina]

Yep.

[slapaho]

would 17cc domes be better

[bkabina]

What are your mods and elevation?

[slapaho]

right now i have a milled haed wiseco pistons 7 degrees in timing v force reeds pro design intakes 35.5 ftz carbs and toomey tg pipes pretty close to sea level and have 16 40 gears

[350duner]

What is your compression right now?

[MULLET~BOY]

if your going for more top end you don't want a tone of compresion probably around 180 psi

[Aussie Quad Racer]

both too much timing and compression will rob you motor of top end horsepower. It will not allow your motor to rev out freely. How do you know when it has too much? well that all depends on the tune of the rest of the engine and the only real way to know is dyno it.

[BakoBanshee]

i was just thinking, if someone were to run 15cc domes and port the jugs to allow some over-rev, wouldn't you have a power-band that had a pretty broad power curve? Does anybody run 15cc domes and if so how is the bottem-end power?

[Aussie Quad Racer]

you do not understand compression and exhaust port duration, raising the exhaust port reduces static compression but when under load at high revs, it will have more compression due to better signal (within a small rpm range) at the port drawing more fuel into the cylinder and pushing unburn gases back into the cylinder

[Josh A.]

Do the big carbs slow you down with no porting?the only motor id run 15s on is an alky FULL out 350 with a pvl, drag port it and get a pvl then you can use all that compression