Jet size Porsche!

[Maikauto1974]

Hello!
I am from Austria and I have the 1s system in a porsche 993 twinturbo ists for hill climb racing.
Today I have one 0,7mm jet between the intercooler and the throttle body.
Now my question. What ist the best size for this engine?? Now i have 600HP.
Ist the 0,7mm jet enough or should I change it to two 0,6mm jets.
Thanks.

[JohnA]

I would prefer the two 0.6mm jets, because they would both flow the pump to the maximum (350cc/min or thereabouts, not bad for your power levels)
Atomisation might be better too --- depending on where they are pointing obviously.
Ideally you don't want them pointing at a wall, or having tight bends afterwards, because atomisation will suffer and -more important- might vary from cylinder to cylinder.

I'd be interested in what others think. :smile:

[markbudgen]

Hello,

I've been running a 2 stage system on my supercharged 993 for about 3 years now, no intercooler. I run a 0.6 as the 1st stage to avoid too much flow at low rpms and add a 0.7 from about 4500 rpm up. 50:50 methanol:water mix. My water:fuel ratio varies as a result from about 8-15%. I also use a pre-pump priming pump to boost the flow potential of the race pump to about 450cc / min tested with good atomisation. The car just loves it. I have tuned the car AFR lamda as a result to between 0.84 and 0.87. You will probably need a little more than me given mines only putting out about 380hp.

BR, Mark.