Ricks tanks

[Tino]

Thanks for the reply's!!

[Blown353]

Fuel heating is a problem with any high-volume fuel system, and some pumps are much more prone to vapor-lock than others.

There are several good ways to plan your fuel system to keep fuel heating and vapor lock issues under control. Good baselines are to run a pump proven to be reliable and size the fuel pump to give you a bit of over-capacity at your maxiumum HP but not a *lot* of excess capacity. Also run the fuel lines wisely away from heat sources, and in areas they can't be avoided use insulation and heat shields as required.

Now for ways to manage fuel heating:

1. Use a a load-based or RPM-based controller to slow down the pump when the volume isn't needed. Aeromotive, Weldon, and a few others make controllers. pwm speed control is preferred to a voltage step-down controller, as simply reducing the voltage will make the pump response "lazy."

2. Dual pumps, each of smaller capacity than the single pump that would be required; have the second pump turned on either by a trigger out of an EFI box based on manifold pressure, RPM, at a certain injector DC, TPS %, or another variable, or you could trigger it seperately with an RPM activated switch or a Hobbs switch for manifold pressure, etc. You can even go one further if you need a really big fuel system and have the primary pump working off a PWM or voltage controller as in #1.

3. Run a slightly lower volume pump and run a voltage "step up" box for the pump that boosts the voltage (and therefore fuel flow) when it's needed. I run a Kenne Bell "boost a pump" with my SX fuel pump. I don't need it, but at normal alternator voltage my engine is using about 90% of the pump capacity at WOT and full boost and I wasn't comfortable with only 10% headroom. I have the Kenne Bell triggered off dual Hobbs switches at 3psi of boost and it bumps the fuel pump to 16.75 volts, giving me an extra 100 lbs/hr out of the fuel pump which is plenty of extra capacity. Since SX rates the pump for 16 volt duty this isn't a longevity problem.

3. Run a fuel cooler on the return side after the engine-- which really isn't a bad idea with any configuration, since cooler fuel = more power. Several vendors sell heat exchangers ideal for this application, just plumb them in on the low pressure (return side) of the regulator. The only negative here is that you've just introduced more lines and connections and potential leak points into your system-- luckily they're on the low-pressure side.

The safest way to go IMO is a single pump big enough to do the job, a step-down speed controller to reduce fuel flow and therefore minimize heating during low-load cruise conditions, and also run a fuel cooler. If the controller dies you can bypass it and get home, and the cooler should prevent vapor lock even at continuous full speed/volume pump operation, and you won't have any issues with the engine starving for fuel under WOT. You also don't have to worry about starving the engine as you could with a dual pump or step-up system if your pressure switches fail.

However, the redundancy of a dual-pump setup is nice because you can get home if one pump dies by manually switching on the second pump-- you just need to remember to keep your foot out of the throttle as you won't have enough fuel volume to feed the engine at heavy load with only one pump.

Troy