Going to install a surge tank in my rx7 and would like to know if the stock 3rd gen in tank pump is sufficient to fill the surge tank before the fuel gets to the Aeromotive 1000 pump or would the Aeromotive pump drain the surge before it has a chance to refill.

 

Sure, you're talking only a 1-3 gallon MAX tank.&nbsp Only you're doing serious WOT blasts, the stock fuel pump should be sufficient (i.e. 1/4-miles drags).



-Ted

 

do you have to run external pumps with a surge tank? i have been told if you have 2 good intank pumps there is no need for external

 

Yeah, I'm no expert...but I think you'll be fine. When you add the surge tank it creates a 0-10 psi environment for the stock pump. So it will flow MUCH better than without the surge tank @ 45 or whatever psi.

 

Nice choice on a pump, simlilar to what I am running. What is your total fuel system plans?

 

That's exactly what I'm running, just run the fuel return line back into the tank and run anouther line out of the top of the tank back to the gas tank for over flow... this way the stock pump fills the tank and the excess from the fuel pressure regulator also keeps the tank full... Also make sure you get there fuel pressure regulator for that fuel pump I was having problems with a large Sard fuel pressure regulator not being able to control the fuel pressure under boost due to the volume of fuel flowing threw it...

 

but can you run one with internal pumps only? same set up though retrun to the can and from the can to the tank

 

The point of having a surge tank is so you can have a large fuel pump either inside the tank, or after the tank, and not have to worry about it sucking air which instantly kills fuel pressure. there'd be no point in having one after all fuel pumps, and i don't think it would be possible as it would always be pressurized (and thus can't really have a return line on it, unless you add a regulator) and fuel pressure would still drop if the in-tank pump sucks air.

 

The surge tank idea was really made popular by people that converted carbed vehicles to efi, when the lacked a return line.
The other type of surge I have seen is on a drag car one of my old friends had, the pump volume and pressure fell right off on launch because of the fuel pushing back against the pump, so one pump filled the surge at low pressure but high volume, just enough psi to overcome the accelaration force of the car, the second pump pulled from the surge to the carbs, the surge was just an aluminium tank with a holley float bowl assemble on it to control level.
The idea of a reg on the surge return is interesting, some other methods, include a fitting close to the top of the tank, so when the fuel level gets to a certain height its automatically returned to the tank in the rear of the car, the problem with constant flow systems like that though, is heating and airation of the fuel.
Check www.sdsefi.com on their tech/project page, they show how to make a cheap surge tank..
I would be tempted to put the stronger pump in the back of the car, as it will have more fuel line pressure drop to work against and also the force of accelaration working against it, the lesser pump, if mounted fore of the motor would accelaration working with it, and have alot less fuel line to push through, just some ideas..Max

 

Here is my fuel system set up...

 

ok, somebody correct me if i'm wrong, but i always thought that a surge tank was just an alternitave to putting a sump in your fuel tank. if the surge tank's only purpose is to prevent the pump from sucking air on hard launches, then why not just put a sump in the gas tank? wouldn't the sump serve the same purpose without having to use 2 pumps and a surge tasnk? i guess what io'm asking is what is the advantage of using a surge tank over a sump?

 

a sump would work too, but a surge tank is easier to do, since you don't have to take the gas tank out and have it modified. Plus, a surge tank works under acceleration in all directions, so, say, you don't have to worry about sucking air in the middle of a long fast corner.

Plus, like Max said, it makes life a ton easier for people converting carb'ed cars to EFI. Typically, the gas tanks in carbed cars don't have much in the way of baffling inside, because if the inlet sucks air and fuel pressure drops, the car will still run on the fuel in the float bowls, for quite some time, before performance suffers. EFI cars are a different story, since the injectors rely on fuel pressure to move fuel.

 

Correct me if i am wrong but on your diagram you have your 1000 hp pump going to your secondary injectors first,thought it was the other way around with fuel entering the primaries and leaving the secondaries.

 

It's a common mod to reverse the flow...I kept the OE rail and tossed the pulsation damper. The advantage being that the bigger injectors "see" the gas first.

 

What he said... I'm running the K2RD fuel rail for the 1,600's and I modded my primary rail so the 850 would fit.. I also tapped out the fuel rail and put in -6 fittings... I have -8 feeding the aeromotive pump and out of it to the secondary fuel rail, then -6 out of it to the primarys/regulator/return...

 

It's sad to see people running aftermarket FPR's with dual inlets ports and run a series (stock) fuel system...

Come on guys, change it to a parallel fuel rail system and make maximum use of the aftermarket FPR!

Have no clue what I'm talking about?
http://fc3s-pro.com/TECH/MODS/FUEL/fpr.htm



-Ted

 

Hey where do i find that y fuel splitter block,do i have to make it or buy one ,need some addresses.

 

For the y splitter there are some nice ones at summit
www.summitracing.com

part number BGI-170026

Matt

 

There are two options that I am aware of.

I believe Paxton/Aeromotive makes one that requires adapters to fit -6AN.

NOS also has fuel y-splitters that come in red OR blue anodized WITH -6AN male ends.&nbsp This means your plumbing is slightly cheaper due to the fact that you don't need an adapter going into the splitter block and can run straight -6AN female hose ends.&nbsp Jegs part numbers 741-17835 (blue) and 741-17836 (red); price $29.99 each.&nbsp One caveat, the ones I've seen have pretty faded anodized finishes...

There are other brands that also require NPT (3/8" or 1/2") adapters to AN that you can use...



-Ted

 

Ted: you are sooooooo kind indeed for your help! I was at a sticking point with my fuel system debating on which way to do it when all of a sudden the lightbulb lit. Thank-you for helping my get over my little hurdle