I'm looking at buying a 5K powered rolla and my plans are to boost it. (supercharge or Turbo). i kno sticking a 5K head on a 4 or 3K will lift comp thru the roof. so if i were to put a 3 or 4k head on a 5k would this lower comp enough to leave the internals alone. And which head out of the 3 or 4K has the biggest/smallest chamber size?

 

CHEERS

Ryan

Yep, thats exactly what I have done with my boosted motor. 3kbp head on a 5k and CR is done around 8:1 now.

 

3k has a smaller combustion chamber than a 4k, so a 4k head would lower it even more, but not too much more. :dance:

Thanks man,

 

i didnt even know someone had done it. But it helps now.

 

How many pounds are you pumping into it with the 8:1 CR?

Also would she still run ok as N/A with the low CR?

 

CHEERS

Ryan

Only about 14psi at the mo cause of my ceramic wheel.

 

I'm not the only one to have done it mate. Madrolla68 also has and he's put over 23psi into one so far.

 

I've also ran over 20psi on a stock standard 4k!!!

 

The lower compression makes it very responsive low down in the revs, NA it'd be very sluggish in the top end.....obviously!

Yea, thats what id thoguth would happen. (low comp = sluggish

 

Might make it look like some of the rollas on the road today :yes:

 

Just asking because i have a little plan in the making. :dance: