7 replies to this topic

[bigrob]

Hi guys

Im going the turbo route with my 998. Im not gonna run a particularly high compression so it'll be a low boost.

My question, do i need to run the metro turbo head on the 998 block, or just get a good flowed 998 head?

Cheers
Rob

[Carlos W]

You need to work out the compression ratio on your 998 and ensure it's low enough to run a turbo

[bigrob]

Yeah thats part of the plan.
The turbo heads have stronger exhaust valves to dissipate heat if i'm not mistaken?

[BritishRacingGreen]

They do, but it's not a necessity. Plenty of people running standard valves on a turbo setup. My 12G295 turbo head just has stainless valves. If you don't want to fork out for the turbo head and having your block pocketed you can run your standard head so long as the resulting compression ratio is low enough. Porting etc will just affect the final numbers.

 

With regards to compression ration I'm planning on 9:1 and 12psi, using a ducted intercooler. The compression ratio you go with will depend on your setup. If you give me more info like what you're using the car for, how much boost you want to run, whether you're going to have an intercooler, what turbo etc I can be more help.

[bigrob]

Ok mate cheers. Im using the standard metro turbo unit. Im not planning on running a high boost, super revvy race car. Its gonna be a daily road car with a little bit more go when i need it. I am planning on running an intercooler yes

[BritishRacingGreen]

The standard metro turbo T3 Actuator is set at 7psi (or 4 - I can't remember), Which at 9.4 or so with a good intercooler should be reliable. 

[Turbo Phil]

How much boost are you planning to run ? I probably wouldn't run to much on the standard non Turbo ex valves & iron guides.
I assume you realise the 940 head has smaller chambers than the standard 988 head, thus raising the compresssion ratio ?

Phil.

[bigrob]

Yeah i was planning onsticking with standard boost.
No i didnt know about the chamber sizes, the thing that was putting me off using the turbo head was the need to pocket the block