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Re: help me build an a14 | Subject: Re: help me build an a14 by L18_B110 on 2003/9/29 2:40:18
a mech fuel pump shouldn't cost much bhp to run, and I agree with dodgeman that an elec fuel pump will not net any gains there, but it also will not draw enough amps to load up the engine via the alternator as the headlamps do.
The advantage of an elec fuel pump is that is does not conduct heat to the fuel. And in higher volume pumps set up properly with return lines, by constanly recirculating the fuel while the needle and seat is closed, there is a constant supply of cool fuel available to the carbs, especially if some thought is put into the placement of the fuel lines.
The electric/thermo fan is another story. A fixed blade fan will cost bhp to run - and most of the time the fan is not required. sure the fan will flex and straighten to some degree at high rpm, but it is still an unecessary drag on the engine. By replacing it with an elec fan that only runs when required (ie in traffic and while stationary), you should free up a few bhp. You won't see too many race cars with engine driven radiator fans.
But these are all very small gains, and I see them as essential for my race car where every little bit counts. But for a road going car, the cost probably isn't justified, and there are definitely much bigger gains to be made in the 3 C's (Cams, Carbs and Compression) and exhaust, so spend your money there first - especially if you are building a motor. Spend the money on it and do it right with a few nice little extras like a lightened flywheel and balance the bottom end, and aim for around 9.5 CR for a strong, easy to live with street motor on ULP.
The external accessories can always be added later, (as can the headwork) and I'd start with the electronic ignition myself - not so much for the performance, but for easier cold starts, stronger idle, no more messing around with points etc - just set and forget. good seconhand OEM fans can be picked up pretty cheap at wreckers, and that would be next on my list. But for now, spend the money on the bottom end.
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