Technical STAGE 2 GAS FLOWED & PORTED HEAD SPORTING

[AngelUK]

Hi all....

i’m interested in the stage 2 gas flowed & ported head sporting big valve 34.5/29.5 £ 695.00 will this help the turbo kit that we are planning in having fitted just after christmas as we will be running high boost

 

[paulbfd]

What stage 2 head?

A stage 2 head will more than likely have been skimmed to get the compression ratio up. If you want a modded head on a turbo, you'll need bigger combustion chambers to help lower the compression ratio, not sure how much can be done there.

Aaron (J333EVO) or Pete (Fixit) can probably shed more light as they are Cinq turbo techies.

 

[Catseyes]

I thought you got the head flowed around the valves to lower the CR.

 

[jamie86]

Aaron has a P+P head on his wait for him to pop up or do a search sure he has said on here before where he had his done and whats was done....

 

[J333EVO]

I've got a stage 2 head ported polished gas flowed etc from AutoSprint Design in Birmingham which I think cost about £385. You do not need bigger valves on the Cinq head as they are big enough and I only got my head very lightly skimmed to ensure the mateing face was flat. the guy who did it was very knowledgeable and coudl have sold me bigger valves etc no problem but when i stated it was turbo'd and a road car he said that I didn't need them as the valves are large for a small car and the only benefits that could be gained from bigger ones would never been seen ona road car.

Don't know who quoted you over £600 but thats sounds a bit steep, I've heard of getting 16V heads done for about that!

As an aside there is no diff to tuning a turbo car than there is to tuning a N/A car this is where many folk go wrong with turbo cars they up the boost then wonder why it all goes wrong. Head work is more noticable on a turbo car than a N/A car, the only thing you need to watch is choice of cam shaft as you don't want overlap on the valves opening and closing.