Duke

I think you're on the right track here...
Often the A/R ratios are totally left out when discussing turbos on this forum, which is strange since it's as important as the trim size.


I'd like to know how KKK hotside numbers correlate to A/R, it's a bit frustrating not knowing when comparing turbos!

rage2

Peak TQ was 250 at the wheels. Here's the dyno chart on that one. The pre-full boost duty was also turned down a bit so the TQ curve doesn't hit as hard. Ghetto wheelspin control for winter . This one was on 91 octane shell if I remember right. It was the winter formula too, right at the edge of knock.

jimbo1111

Posted by Duke:
I'd like to know how KKK hotside numbers correlate to A/R, it's a bit frustrating not knowing when comparing turbos!

Conversion from mm to inch in volume.
6mm for hot side x .06102 = 0.36612 8mm for hot side x .06102 = 0.48816 10mm for hot side x .06102 = 0.6102
So a #6 hot side would be 37 a/r, #8 hot side would be 49 a/r and a #10 hot side would be a 61 a/r
Does this help.

J Chen

Hi Rage,
I know that different A/R & Housing
for a given trim will affect how it flows
over the map but the peak flow will
still remain the same.
Tony can you enlighten us on how
Rage manage to attain 460 rwhp
with a 57 trim compressor please ?

rage2

Which brings up a question that I have, how does CFM or lb/min correlate to HP? Also, how does a/f ratio and timing relate to the calculations? For example, if you run 11:1 a/f ratio vs 12:1 a/f ratio, you'll make more power with the leaner mixture and the same volume of air. Same goes for timing, more power for the same amount of air.

BTW Tony, thanks for the detailed descriptions on plotting out compressor maps against the 2.5L and 2.8L motors. This is a great learning thread .

J Chen

Hi Rage,
It just occurred to me. Are you running
race gas like C12 ?
Regards to your questions. If I remembered
correctly, one lb/min equals 10hp theoretically.
But than again there are variables like VE of
the engine etc.
I think timing & A/F are a difficult ones to calculate.
Again it's got to do with the fuel used & how well
the head is able to flow & burn the mixture.
Danno recently mentioned in one of the threads
that advancing the timing of the 2V head did
not produce any power increase at all. Even if
you could get the heads to flow like the 4V heads,
theres still no assurance the performance will be
the same due to different combustion chamber
designs

rage2

Yes, I'm running race gas. As for timing, I've shown that you can gain 10-20hp on pump gas by tweaking high rpm timing on a 2V head. Take a look at the 12psi plot I posted above. I'm making peak horsepower after 6500rpm range by minimizing torque drop past 5400rpm.

dmoffitt

thx tony

Pauerman

Tony, great detail on the graphs man!!

Thanks for shedding light on an area that doesn't get as much attention as it should.

J Chen

Hi Rage,
Yes I see it but that's at 12psi.
But when running at 18- 20 psi
would be a different story.
BTW what's the specs of your
2.5L engine ? I remembered that
you were one of the first person
to use the SDS system. Are you
still running with it ?

porshhhh951

wow great thread guy's. I am learning alot