Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: ngrainqey on 16 January 2009, 23:22:08

Title: another alternative heads use....
Post by: ngrainqey on 16 January 2009, 23:22:08

hiya, i dont know why but i got talkin to my mate about the turbo x25 project and using 3.0 heads- for some reason we ended up talkig about using the 2.5 heads on the 3.0 lol.... can you use them or is the combustion chamber too small/compression ratio too great?

thanks

Title: Re: another alternative heads use....
Post by: Martin_1962 on 16 January 2009, 23:38:20

3.0 on 2.5 lower compression

2.5 on 3.0 raise it a lot, possibly past super unleaded level, but LPG should work

Title: Re: another alternative heads use....
Post by: Kevin Wood on 17 January 2009, 00:38:59

I think we worked it out and it was around the 12:1 level. Too much really. You could, of course, enlarge the combustion chambers, skim the piston crowns or fit thicker gaskets to bring it down to something sensible.

Kevin

Title: Re: another alternative heads use....
Post by: feeutfo on 17 January 2009, 08:10:07

 whats the stock compression ratio for the 2.5?
If you want to use decent boost you need to reduce compression ratio. Fairly sure there is an equation to calculate for your engine/turbo etc?

Title: Re: another alternative heads use....
Post by: Kevin Wood on 17 January 2009, 10:55:41

Quote

whats the stock compression ratio for the 2.5?
If you want to use decent boost you need to reduce compression ratio. Fairly sure there is an equation to calculate for your engine/turbo etc?

10.7 IIRC

Kevin

Title: Re: another alternative heads use....
Post by: feeutfo on 17 January 2009, 15:02:39

Quote

Quote

whats the stock compression ratio for the 2.5?
If you want to use decent boost you need to reduce compression ratio. Fairly sure there is an equation to calculate for your engine/turbo etc?

10.7 IIRC


Kevin

i guess roughly a quarter off of that, but needs to be worked out correctly....

Title: Re: another alternative heads use....
Post by: ngrainqey on 17 January 2009, 18:01:45

Quote

whats the stock compression ratio for the 2.5?
If you want to use decent boost you need to reduce compression ratio. Fairly sure there is an equation to calculate for your engine/turbo etc?

im on about using x25 heads on an x30 chris... my 3.0 has died thats all and i think it may be the heads (i luckily have 3.0 and 2.5 heads that dont have bent valves) but would rather use the 3.0 heads on the turbo lump :(

Title: Re: another alternative heads use....
Post by: feeutfo on 17 January 2009, 19:12:38

Quote

Quote

whats the stock compression ratio for the 2.5?
If you want to use decent boost you need to reduce compression ratio. Fairly sure there is an equation to calculate for your engine/turbo etc?

im on about using x25 heads on an x30 chris... my 3.0 has died thats all and i think it may be the heads (i luckily have 3.0 and 2.5 heads that dont have bent valves) but would rather use the 3.0 heads on the turbo lump :(

?....right, and what compression ratio will that give you ? Have you worked out what you have v what you actually need? Plenty of info on the web for all this mate. No good at maths myself.
What ratio are you trying to achieve?

Title: Re: another alternative heads use....
Post by: ngrainqey on 17 January 2009, 19:15:26

with the 2.5 heads on the 3.0 just standard would be fine tbh or maybe 11/1 comp ratio at the most
(i bought the 3.0 heads for the turbo project thats all)