Need help to calculate.

[Tekken]

Hi,my first post here-nice forum.
I have a drag race vw beetle with an aircooled turbo engine.I really need some good help from you guys,to calculate what jet size/sizes to use based on my fuel jet sizes and pressure.I use a 1S system injected before turbo.

-2,5 litre 4 cyl. aircooled engine,approx 500-550hp
-Draw trough turbo setup-non intercooled
-Modified Holley 850 carb,VP racing fuel MS109

On full throttle with 7psi of fuel pressure,active fuel jets are:
two 1,5mm
two 2.4mm
two 3.2 mm

Thank you.

Kind regards.
Stian-Norway

[Richard L]

I am not very good in working out exact fuel flow per minute on Carburattor fueled cars.

Based on the 200bhp per litre of fuel, your estimated fuel flow will be approximately 2500cc/min. The 1s flow about 300cc/min, a/f ratio is 12%. That is quite normal ratio for a wrter injected engine.

I think you can run a 1mm nozzle., allowing about 12KW of cooling.

[Tekken]

Originally Posted by Richard L

I am not very good in working out exact fuel flow per minute on Carburattor fueled cars.

Based on the 200bhp per litre of fuel, your estimated fuel flow will be approximately 2500cc/min. The 1s flow about 300cc/min, a/f ratio is 12%. That is quite normal ratio for a wrter injected engine.

I think you can run a 1mm nozzle., allowing about 12KW of cooling.

Hi Richard,and thank you for your responce.
I tested a 1mm nozzle last season,but did'nt have anything to monitor exhaust temps.Now I have installed a datalogger,and should see lower temps.How do I know when there is too much water,do the engine just loose power?And would you advise to test with 75/25 water/methanol or 50/50?Going testing Wednesday 29'th.
Thanks.

Stian

[Richard L]

I would start at 1mm M75:W25 and work towards 50:50. At all time listen out for knock.

[maxc]

Originally Posted by Richard L

I would start at 1mm M75:W25 and work towards 50:50. At all time listen out for knock.

Some old timers listen with a stethoscope hooked to the block.