3 replies to this topic

[Leekr89]

My 1330 engine is currently running approx 90hp at the wheels and I'm reasonably happy with the setup, but I now fancy doing something different with it and putting the turbo setup I have to good use.

My main concern is if I can can get away with getting the compression level down low enough without having to remove the pistons and have them machined down.
They are AE 21253 pistons with an 8.4cc dish. From what I have read these pistons work well in a turbo setup handling good boost, I'm looking to run around 8-10psi of boost safely, so would need to possibly run a compression ratio of around 8.75-1?

I have a spare 12g940 that I'm planning on using to drop the compression right down on, putting turbo valves in etc.. but is it possible to machine out enough meat in the combustion chambers to run the compression at this level? If it's not and I will have to remove the pistons then so be it, the engine will need to be stripped to replace the cam with an avonbar one anyway.

The pinned compression ratio calculator doesn't appear to work so I'm just looking for some advice, cheers

[minifreek1]

Im no expert on this subject at all, but can't you fit 2 headgaskets to lower the compression ratio...?

[FlyingScot]

Yes in principle opening out the combustion chambers should be able to get you close, you could also use a decompression plate with two head gaskets.

FS

[mini13]

if youve got an unskimmed head, then you should be able to get the chambers taken out to 28cc, which will get you down to about 9.1:1