I'm in the process of setting up a nitous system and was wondering if i can put a inline fuel pump inline before the stock fuel pump/ regulator with out any problems. like this carter pump from summit
http://store.summitracing.com/partde...57#largerimage

 

Funny you should ask! I run almost that exact same pump out back by the tank in combination with a block-mounted fuel pump up on the engine. This combination of fuel pumps is my go-to fuel system for a performance street car. Absolutely bulletproof. And yes, I'm a nitrous junkie just like you. My best (a previous car) was 11.80 @ 116 using this fuel system to supply a mild 400ci motor with a plate nitrous system. Pressure was rock-steady through the whole run.

The electric fuel pump, being low pressure, will NOT require a regulator- the mechanical fuel pump up front will do all the final fuel pressure regulation for you. In fact, you can buy the lower pressure 5 PSI version of that same pump and it'll do everything you need it to. That's what I run.

Just tap into the fuel line after the mechanical pump for both the carb and the nitrous system. Dirt simple and dead-nuts reliable.

 

so you use the 6 psi or the 8 psi rated pump in line with the stock pump?

 

I use the Carter 5 PSI pump. And the front mechanical pump is a Carter 6 PSI unit. Maybe Carter changed their ratings recently. They used to be labeled as 5 or 7 PSI pumps.

Don't worry about a small difference in pressure between the electric and mechanical. Lately I have been using the Holley Red pump out back (7 PSI, 92 GPH and quieter than the Carter) against the same Carter 6 PSI mechanical pump up front. The electric doesn't "outrun" the mechanical and the actual observed pressure at the carb is 6 PSI under all conditions.

No reason it wouldn't work with a stock mechanical pump up front, though.

 

how loud is the carter pump? your right about the carter pumps 5 and 7 psi. the only reason for getting the 7psi is i have the return style regulator so i figured all of the unused fuel would just be sent back to the tank, or do you think i should stick with the 5 psi pump?

 

Hold on, I thought you were running a mechanical fuel pump up on the engine and an electric out back. That's how I run mine and I have no regulator- the mechanical fule pump will do the regulation.

Factory mechanical fuel pumps have a retrun-style regulator built into them. If that's what you're relying on then it will work jsut fine with either pump. The pressure of the electric out back is relatively uniportant. All it is doing is giving a "boost" to get the fuel up to the mechanical pump which does the real work. That sounds like it's no big deal, but it makes a HUGE difference in the amount of fuel the whole system can give. I was running out of fuel pressure running only high 13s with just a mechanical pump. With the addition of the electric out back I could go high 11s with dead-solid fuel pressure.

If you are running an aftermarket mechanical fuel pump without a return line up on the engine then you want to keep the presure of the electric pump reasonably close to the pressure of the mechanical pump so it doesn't "outrun" it. 1-2 PSI more, probably no big deal. More than that and the electric will probably outrun the mechanical and cause the pressure to creep up during periods of low demand (idling).

Now if you are running very high pressure mechanical pump (15 PSI race pump) up on the engine with an external bypass-style regulator I can't really speak to that, as I have not done it. I suspect that it will still work just fine with either electric pump, but I haven't done it myself.

The Carter pump is pretty loud. I can almost hear it over 2 chamber Flowmasters with turn-downs under the car. The Holley is probably about twice as quiet and it's what I'd use if you drive the car on the street with any exhaust that isn't obnoxiously loud.

 

sorry for the confusion, what i ment to say is i have the stock return bypass regulator/pump. also i think i'm going to try the 7psi carter pump. what type of nosie is it? a loud clicking? or a high pitched whine? unless its really too loud, thats where your oppinion comes in. is it really that annoying?

 

It's a medium/high pitched whirring noise. Like... VVVVVVVVVVVVVV!!! The Carter pump comes with a mounting bracket that has some rubber isolators on it. Still, the noise is very noticable over all but the loudest exhaust systems. The Holley is much quieter.

Your stock fuel pump/return lines should work just fine with it.

 

do you have any pic on how you mounted your pump/ tapped into the lines?