best cosworth pistons? wossner/wiseco/arias etc etc

[cozzylee]

ah ok so im guessing the oe comp ratio would be no good even with a t34 holding 20psi

[mark shead]

ah ok so im guessing the oe comp ratio would be no good even with a t34 holding 20psi

No need for comp to be lower than stock with any turbo combo.

mark

[Mike Rainbird]

No need for comp to be lower than stock with any turbo combo.

mark

Even with standard ECU and a car used regularly on track ?

Personally, I'd want to see no higher than 7.6:1 with a T34, as above this you WILL get det on a high speed run with 25psi held......

Even with 7.6:1, I did three back to back runs at Bruntingthorpe (with the cool down between each driving gently around the back of the circuit) and on the third run there was a faint hint of det. Therefore, I knew what I could get away with. On standard compression, the det would have been there by the end of the first run or would have required so much ignition pulled out, that it would have been pointless running at that level.

Obviously I am talking about having something that is 100% safe in all conditions.....

[Mike Rainbird]

ah ok so im guessing the oe comp ratio would be no good even with a t34 holding 20psi

That would be fine .

[mark shead]

Even with standard ECU and a car used regularly on track ?

Personally, I'd want to see no higher than 7.6:1 with a T34, as above this you WILL get det on a high speed run with 25psi held......

Even with 7.6:1, I did three back to back runs at Bruntingthorpe (with the cool down between each driving gently around the back of the circuit) and on the third run there was a faint hint of det. Therefore, I knew what I could get away with. On standard compression, the det would have been there by the end of the first run or would have required so much ignition pulled out, that it would have been pointless running at that level.

Obviously I am talking about having something that is 100% safe in all conditions.....

Mike

When I map them there is no cool down in between so they are mapped for max heat and they still make the correct power.

Mark

[Tore_TJ]

Mike

When I map them there is no cool down in between so they are mapped for max heat and they still make the correct power.

Mark

To read your mind and steal your knowledge would be very helpful at times

[warrenpenalver]

would be interesting to know why the old school tuners went down the low comp route in the first place if as you say now Mark, its not necessary.

Whats changed?? is it mapping ability??

[mark shead]

would be interesting to know why the old school tuners went down the low comp route in the first place if as you say now Mark, its not necessary.

Whats changed?? is it mapping ability??

I would say in the early days it would have been the adjustabilty of there mapping interface and experiance,
Then you get stuck in your ways and not experament but there will also be completly the wrong specs that wont work with the higher comp side,
I am not saying go 10-1 but I cant see why you would want to change away from the stock comp.

Mark

[Tore_TJ]

I would say in the early days it would have been the adjustabilty of there mapping interface and experiance,
Then you get stuck in your ways and not experament but there will also be completly the wrong specs that wont work with the higher comp side,
I am not saying go 10-1 but I cant see why you would want to change away from the stock comp.

Mark

Is there still need for small exhaust housings then? Or is this just down to the ability of the mapper?

[mark shead]

Is there still need for small exhaust housings then? Or is this just down to the ability of the mapper?

A small housing can have a effect but I find choosing the right turbo first helps rather than some companies that fit a big comp wheel on a small rear.

Mark

[Tore_TJ]

So what do you usually use with the 3076 then? I belive it's a turbo you use alot?

[cossiedavid]

im on 8.0.1 comp with 500bhp and no problems , less lag to than say 7.2.1

[mark shead]

So what do you usually use with the 3076 then? I belive it's a turbo you use alot?

.82 on both a 3076 and a 3071, if you want to reduce lag on the 76 use a 71 instead.

Mark

[Tore_TJ]

Ok.. why? To keep the backpressure down? How much is the 3071 capable of? you know my spec (well basically )

[mark shead]

Ok.. why? To keep the backpressure down? How much is the 3071 capable of? you know my spec (well basically )

On a 3076 with a .63 its a bit on the high side, the 3071 is good for around 500hp flat out and the 76 is good for 560hp, but genrealy take 20 to 30hp off those for a average engine.

Mark