by Dave Koehler


Dear Sir,

I need to know can I gain 400hp from a 2.5 Chrysler inline 4 engine n/a using N2O and race gas or methanol. Turbo does this power, block is strong enough, but can it be reached in a naturally aspirated application?




I will take your word for it that the engine, transmission and chassis can handle copious amounts of nitrous. It is technically possible to jam that much fuel and nitrous down it's throat. However, whether the engine can absorb, burn and in turn create that much of an increase is another story. Please note that I do not see it as feasible or sensible to attempt injecting that much of an increase at the hit of the throttle on a 4 cylinder.

A pro drag racing style nozzle system (which means one nozzle per cylinder minimum) will be required. Some study must be given to a two stage system or a progressive nitrous controller so you can roll into it in much the same way the turbo works.

Have a safe race,

Dave Koehler


I have a fuel problem. I have a '74 duster with a 360 and a rons toilet fuel inj. The motor 11.0 com huges cam 622 lift heads are w2 mopar. They set me up 31 nozzles. The car runs good 900 ft. then lays over. I barrowed exhaust temp. gauge. When I get 900 ft. the exhaust temp. goes to 1560 degrees. I had 85 pill in it so I went to a 65 pill and the temp. only went to 1510. So, I went to 35 nozzles with 65 pill and the temp. was still 1500 degrees and it's rich idling no matter how much I adjust barrel valve and lean on the top end. Is my pump bad or do I have other problems?



IF the car used to run fine and you now have to keep richening it up to maintain the same ET, the pump is dying. What do the spark plugs tell you? IF you are indeed lean, you should be seeing a color change in the strap and the first threads of the plug. If you keep going richer and it keeps slowing down, then go the other way.

Without knowing the actual flow rate of the pump (flow testing) it is not credible to comment on the nozzle and main jet choices.

Have a safe race,

Dave Koehler

To contact Dave Koehler write fuel@dragracingonline.com


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Fuel for Thought — 12/9/03

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