A15 with H72 head - what's my CR?

[rbastedo]

Anyone know this or tell me how to figure it out please?

I have the H72 head and it also has a casting of "105" on it - stock height not milled.

The chamber area is open not heart shaped.

I'd really like to know or find out how to compute the compression ratio.

Thanks!

[metalmonkey47]

http://www.carcraft.com/techarticles/calculate_compression_ratio/index.html

 

 

Read up on this :)

[rbastedo]

Thanks, I should have been more specific.

It's not that I don't actually understand compression ratio.

What I'm wondering is if the volume of the compression chamber is known and the volume of the cylinder is known and or if I can look these numbers up somewhere?

Thanks again. :cool:

[kurt appley]

Rick: Those heads had a comp ratio of 8.5 to 1 on a A14. If you know that its not too hard to calculate the ratio on a A15. Did it a couple of days ago and believe it comes out to around 9 to 1.

 

 

KA.

[datzenmike]

I got 9.1 but this is assuming 1.4 liters and 1.5 liters exactly. I doubt the motor size is exactly that. If you know the exact motor sizes in cc's I can get closer. 9:1 sound about right.

[rbastedo]

Thanks very much guys, that is very helpful and I appreciate it!