fast951

Isn't Euro 99 Octane the same as USA 93-94Octane? And you were running 1.4bar boost!

fast951

Euro 98oct is similar to USA 93oct. Running 951 8V head, 8.8:1 CR and 1.6bar boost? You think this equals a good tune??

Let's see, you have fuel and ignition to tune. Let's go safe rich and say 11:1AFR (not ideal for power). With the above engine configuration and fuel octane, will need ignition timing so retarded (for knock control if possible) that EGTs will sky rocket. Not what I label as a good tune.

Obviously, something is missing from this equation. But what do I know, this is a internet HP race...

V2Rocket

pretty sure the 2.5 head doesnt work on the s2 block.

Duke

It does, with a reshape of the front coolant port.

Chris White

ANYTHING works if you have the budget...

actually the 2.5 head on a 3.0 block is not a big deal - as long as you are getting the head worked on.

Olli Snellman

2,5L heads have been modified for ages to fit S2 block. That's what Kert (CMF) also did.

Here's few pictures which tells cleary the difference

2.5L head



2.5L block



2.7L head



3.0L block

333pg333

My point exactly John. Therefore I said it had to be a good tune to hold together. Doesn't quite add up.

fast951

Exactly, you know how it is. I was just clarifying

Rogue_Ant

Dyno /= endurance race.

I see no reason to say that the tune was not good. That the motor held together at the boost (~23psi) on pump fuel dictates that it was, in fact, a good tune.
Not every 951 is subjected to survive for 20min @ WOT. A short blast is significantly less hard on an engine.

The typical 951 thought process on boost is ancient. (though perhaps not unwarranted, due to the market TA)


-Rogue

fast951

Ok, so you are saying if it lives for a dyno run, then it's good? Well, if that's the criteria, then it's a different story. To me a good tune is that the car must live and be able to handle the track environment. Even for the street, the above conditions are not a good!

What is the new thought process on boost (for the 951 on pump gas)?

Chris White

Turn the boost up untill the engine breaks and then back off 1 psi....

Rogue_Ant

Yes we are talking dyno, the #1spot set that precedent. Thats what this whole thread is about.
For the street why are the conditions not good?
Also what is stopping the owner from simply lowering the boost and tracking the car?

Looks to me like CMF just set that bar.

fast951

No! You mean go 1 psi higher. That makes more sense

fast951

Why don't you run 25psi on pump gas with 8.8 CR then you will easily figure out why it's not good! (E85 excluded!).

As for the new bar, let's see how many are going to try it and tell about it. It will be interesting to watch....

Rogue_Ant

Don't assume I haven't.

That is why its 'the bar'. If everyone could do it, it would be the norm.