Using the in-tank fuel pump??

[1994Firebird400]

I'm building a pontiac 400 for my fourth gen and keeping it carburated. I read on a few websites of retaining the in tank fuel pump by using the approprate fuel regulator. I will have to upgrade to a larger pump regardless but this seems like a good idea to me. I should be able to retain the stock lines correct? Another question too, If the larger pumps are rated at a max output at a given pressure, how can I go about figuring the difference in output for a carburated vs fuel injected set up? Given the big pressure difference between the two, I really don't want to wing it and not have enough fuel. I plan on putting around 350-400hp and I maybe spraying it when everything is setup. I guess I need something that can handle around 500hp. So is the intank pump the answer or should I go with an electric fuel pump instead??? Either way It'll be a few months before I start the plumbing for the fuel system.


Thanks alot,


Dave

[1BADAIR]

you will have to have a return line. That will be too much pressure to deadhead. you will need a reg for the engine and one for the spray

[sman]

I dont think youll need a bigger pump either, Could be wrong though.

EDIT: Since when have you been "kirk"?

[1BADAIR]

haha since that donation thread where the guy has 400 kids

[1qwikSS]

haha since that donation thread where the guy has 400 kids

LMFAO

[2002Z4CSS]

Make sure the regulator you install has a return line on it then adjust the fuel pressure to 5-7 lbs.

[1994Firebird400]

Thanks guys for your replies!


I figured all I would need would be the correct regulator and return line but I'm still lost on the fuel pump. Should I just go for a 255 and watch how turns out or should I start with the stock fuel pump and work my way up if needed? Like I said I would rather be safe than the lean the crap out of it when I go to fire it up for the first time. Of course, I will have the proper gauges to monitor but I would feel better knowing before I start it up.

Anyways thanks again and keep those replies coming,


Dave

[sman]

I would think it would be fine for now, how many miles on the stock pump? Cant hurt it to try and see, just keep an eye on the a/f. If its a new motor anyway your not going to start it and beat on it, its going to need to be tuened. Get a fuel pressure gauge and go from there.

[1994Firebird400]

Well the stock pump has 250,000 miles on it and I would be replacing it anyway with a new one. I guess I worded that wrong. I meant either a stock replacement or a higher volume pump. But that sounds great and I will keep an eye on the vitals. I just didn't want to buy a new pump that would be useless. So I'll start with the stock pump and see what happens.


Thanks again,

Dave

[sman]

I think your going to be about the same cost wise stock replacement vs aftermarket, at that point id do an aftermarket, since your already doing the labor. Definitely wouldnt use the one with 250k on it though, cant be much left of it.

[1994Firebird400]

Thanks Sman for your quick reply!

Will using a 255 pump regulated down to the required 5-7 psi cause any issues with wear and tear? I would think that the pump would not have to work as hard at that low of pressure so the pump should last a good long time. The regulator and lines from the tank are what scares me. Any premature failures of the stock lines going this route or is it pretty safe? As long as I get a quality regulator than that should be good as well. Also what are the stock lines good up to? Down the road, I plan on a big inch aftermarket block stroker making close to 700-800 hp. Or should I wait intill I come to that fork in the road?


Thanks again,


Dave

[sman]

No issues with wear and tear, the pump is going to run full boar all the time regardless, it provides its full 50 - 60 psi and the regulator lets 5 - 7 pass through, anything beyond that gets sent back to the tank. I would assume the 255 would cover just about anything other than maybe a big FI setup. The stock lines should hold more pressure than you will use, its a hard metal line all the way to the front, use those with a good regulator and Id say your good to go.