I remember my dad and grandpa talking about horsepower and how much you could expect to get out of a 4-stroke. What I remember best is that it was pretty good to get more than 1 HP from a CI.
Vinson=30.5ci something like 35hp
Eiger=22.9ci something like 27hp
Raptor=40.2ci something between 35-41hp (no concensus on Yamadog forum)
1988 Toyota Pickup would have 172hp from a 2.4l four cylinder if it had the same ratio as my Eiger.
Our Suburban would have 413hp from a small block 350.

And these numbers are all assuming normally aspirated with stock exhaust and carb. Maybe that's why it's so hard to get extra juice out of a stock quad engine. It's already pretty pumped.

Doesn't mean I don't want MORE, but it's still pretty amazing.

 

oh yeah, these numbers are based on 16.38 cc/ci.

 

You got that right. You can clean things up a bit and make some extra power, but the pipes and cams and carbs are so good from the factory that there is no BIG gains on most quads, just small gains here and there.

 

thats a pretty interesting theory.

let us know if it stands true, because the stock numbers you ran by me with the vinson seem correct.

 

If the HP per cc was the same for my truck (Dodge Ram w/318) as my ATV (87 LT500R) the truck would have over 600HP [img]i/expressions/face-icon-small-shocked.gif[/img]

 

While you are throwing numbers around, how does power to weight ratio work?

 

cc stands for cubic centimeters ok

 

how do i make my own therad????

 

You have to be a supporting member to do that

 

From what you said, you should be getting 350hp from a 350 CI smallblock. And that does happen without too much tweaking.

The raptor has 35hp, 33 in california. YFZ runs about 40 or 41 from 439cc.


You can start your own thread by clicking on the "new thread" button on the top of any page. You dont have to be a supporting member to do anything but see the movies or to look into the garage and swap shop forum.