Compression Ratio ?

[cyman 1 1 Cars]

does anyone know what the compression ratio would be if a xu10 crank was used with a standard xu9 engine, (rods,piston)

and compatability.

[Doof 11]

Are you on about reducing the stroke from 88 to 86mm then? why?

 

just use something like this to calculate the CR, i dont know all the values for the 1.9mi:

 

http://www.csgnetwork.com/compcalc.html

[Anthony 1,003]

Quick calculation suggests that you'll lower the capacity to 1860cc and drop the compression ratio to approx 9.3:1

 

That calculator is way more complex than you need Doof - since you already know the bore, stroke, and compression for an Mi16, it's easy enough to work out what difference changing the stroke alone will make as it will solely affect the swept (reduced due to the shorter throw of the crank) and clearance volume (increased because the piston doesn't come as far up the bore).

[cyman 1 1 Cars]

Hmmmmmm, not what i was expecting !

i need around 7.3:1

So i think i will go the forged piston route.

anyone got any contacts or recommendations ?

cheers.

[Gtiracer 0]

hiflow do them, DES developments do them

[Doof 11]

Do you really need a CR that low?!?! Surely with good management you can get away with a higher ratio unless you're going for insane power levels...whats your target? (do you need some 315cc injectors )

[cyman 1 1 Cars]

thanks doof for the offer,

i'm already using 490cc injectors.

i'm already using this compression ratio with good results.

[Doof 11]

Going by the size of the injectors you've got, you are going for nutty power...sounds like fun

[B1ack_Mi16 67]

Surely with the right setup you can boost 1.5 bar on 9:1 in compression without issues.

So 7.3:1 ?? You running 2.5-3bar or something?

 

The 490cc injectors suggest you have no more than 350-400bhp and then you surely the engine can't be very efficient with that low compression.

At least what I think..