Here is a pic of one of our dedicated fuel systems.We are in the process of building one that will not have to have a battery relocated and a system for the corvettes.They should be our very soon.

This one is available now.
The system comes set up for one fuel solenoid.This system has a walboro 255 fuel pump and a aeromotive fuel regulater that can be set for high or low pressure.All parts and fitting are included to complete the install.The stock battery hold downs fasten this system in.So there is no drilling required on the car.


This is the upgrade for people using 2 fuel solenoids.


Dave

 

Of course I like it, but I have one question.....where's the vent?

 

Thew vent is in the cap.

 

That is merely an anti blow up the cell like a baloon device. Or anti suck it down like a pop can device. Or anti I can't yank this cap of my cell because its sucked down device. Those cap vents don't flow enough to support the volume of fuel that can potentially be leaving the system under a big nitrous hit.
But I still like it.

 

I still feel bitter about you coming out with this after I built mine!

To make myself feel better, I'm gonna ask a question.

Any tips on getting the AN fittings to seal up? I have all mine around a quarter turn tight, and many of them leaked. I've been too lazy to go back and retighten, but do I have to worry about overtightening? Same with pipe threads (that have thread sealer on them), do I just crank them down until the stop leaking or?

Thanks, and I guess the info could be helpful to anyone that buys the system too.

 

Finger tight is tight enough with AN o-ring fittings, assuming you are talking about the o-ring non-flared end. The flare end doesn't need to be all that tight either. Snug, you shouildn't ever have to crank down on the fittings to seal. You don't want to tighten an o-ring fitting into submission where the o-ring is completely flattened.

 

I bought new O-rings for the fitting that attaches to the fuel cell. Summit supplied the most ghetto plastic O rings I've ever encountered. They didn't do anything to seal, so I have some earl's O rings (the rubber kind) to replace them with.

The fittings I had trouble with were the ones that came off the regulator and such, or where the lines attach to the solenoids. I was pretty pissed considering I only had 8psi in the system. I'll try retightening them to snug or just past snug for non o-ring fittings. I think I might have been breaking the seals when I tightened fittings further down stream (undoing what I just did).

And a quick question on setting the fuel pressue (since your an areomotive rep),
I have a very similar setup to the one pictured above, but a strictly low pressure version with a holley black pump. Do I set the fuel pressure (9psi) with the system on and just returning extra fuel through the return line or some other way? I've heard mention of flowing fuel pressure, but wouldn't it be the same with a return line as with the system in use.

Will 9psi through the return line be the same as when the solenoids open or will it drop?

Thanks for the reply.

 

You should be able to set the fuel pressure accurately with the system just returning fuel via the bypass, assuming you have a well engineered regulator. Not pimping my own product, a Mallory 4309 is a good one too. A holley red, black, blue pump will be fine for a plate type nitrous system. Since you're running a return system the blue and black pump will never go into bypass at 9 psi. (or shouldn't). If you tried to set the pressure above the bypass pressure you would find greatly reduced flow from the system. I'm assuming you have a NX system as they now use a 9 psi setting. Ultimately your flowing fuel pressure is what matters, but your described system sounds just fine. If you have a fuel pressure gauge mounted under hood on the system note that if it is a glycerine filled gauge that the readings may be inaccurate. A glycerine gauge has no atmospheric compensation and the pressure readings will change with the internal gauge temperature due to varying internal gauge pressure with temp.
The "ghetto" plastic sealing washers are designed to be used with a plastic fuel cell. They work fine for their intended use. Jaz uses them and Harwood did as well. Earls stat-o-seal washers are excellent to use with an aluminum cell.
I always use PST paste when dealing with pipe thread. Pipe thread can be difficult to work with because its not always easy to tell when it in far enough. Coupled with varying tap depths between parts and plumbing can be a chore. We only have a handful of parts that utilize pipe thread, most of our systems utilize o-ring AN ports. Make sure when purchasing o-rings that they are designed specifically for the fittings you are using. What I am saying is that they need to be actual AN thickness and diameter o-rings designed for fuel use.

 

I appreciate the all that info.

It answered a bunch of my questions (even some that I didn't ask). I guess I'll just have to retry tightening the seals on the fuel cell. It's a Jaz, and I just assumed they saved a penny on the seals rather than supply good ones. But if they are right, I'll try giving them a bit more of a turn.

One last question about your comments on the regulator. You mentioned,
and I'm curious if you could elaborate on the pump going into bypass? Do you mean the internal bypass, such as if I were running a "dead headed" system that had no return? I have it setup to run (tank)-(fittings)-(black pump)-(regulator + return line/Guage) and then to the solenoids. As I understood your comments, it won't go into bypass (internally) with a return line to bleed off the pressure? Is the system setup correctly to set the pressue without bypass issues?

I just don't want to find myself on the dyno with a big lean condition. Thanks again!

PS: I have your regulator on my fuel rail and it works great

 

With a true return fuel system the system pressure is at regulated pressure, plus any restriction from the pump to the regulator that would cause a pressure loss.
Say for instance your plumbing pumpimg losses were 1 psi from the pump to the regulator then the pump would see roughly 10psi at the outlet with the regulator. With your higher pressure black pump the internal relief spring should hold the bypass valve on its seat @ 10 psi, thus providing full pump volume at that pressure to the solinoid.
A true return system is one where the supply and demand (outlet) plumbing are on the same plane with no "valve" or cartridge in between. The excess volume is bled off through a valve to maintain pressure.
Some systems incorporate a bypass jet to maintain fuel flow through the system, but they aren't a true bypass design as they still incorporate a dead head regulator and the resultant flow restricting design.
Feel free to tell me what regulator you are using for more info.

 

It's a holley regulator. I don't remember the part number, but I believe it is the one that comes with the Blue level pumps.

I have a 3 an line with a restriction jet that returns to the tank from the regulator.

The whole system is a Jaz fuel cell, Black pump, holley regulator, 8an line and filter (same size from cell and pump) to a distribution point where it splits to 6an for the DP and 4an for the second stage. It has a 3an return line with a jet (.28 nx I believe) for restriction.

 

Ok, with that system you will be able to adjust your regulator with the system off, but you won't know what will happen with the nitrous system activated. I am confused as the whether the pump runs the carb too and if it does is it on the same regulator?
With a jet bypass system you will never recover that flow volume, no matter how minute it may seem. If its all on the same system a flow test will be difficult because the flow to the carburetor(Edit: I thought that he was referring to a double pumper carburetor when he said DP, but in fact he has a Direct Port nitrous system) will be an unknown at wot. If its an independant system the you can run a test, but its dangerous.
You would put your plate and plumbing in a bucket and activate the fuel solinoid with the pump on. Note your flowing fuel pressure after it has been activated for a couple of seconds. You will most likely see a pressure drop after activation. Raise the pressure regulator while the system is flowing until it matches your spec. Don't worry about the static gauge reading after the flow test.
We can move to email if it would be better for you. I'll send you my address.

 

NO!! Don't do that!

This discussion is too good. You have to stay here. Sorry... Social contract and all.

 

Haha, I haven't heard from him yet.

I'll post anything relevant when I hear back from him.

Mark

 

I don't mind keeping it here, we kinda hijacked Dave's thread, but it is relavent to the topic too.

I'm acctually runing a stock EFI system and a complete standalone fuel system. The two systems are completely independent of each other.

Does the middle part of your post,
still apply to my setup? The jet is only in the return line to keep pressue up, but still allow air to bleed from the system on initial startup.

As to bleeding it, I don't mind and almost assumed I would need to undo the ends and run the system open.
If this applys to my setup, should I set the pressue with both ends of the fuel system open? I have two nitrous systems running off this fuel system so do I set it with the most possible fuel flowing? If I set it this way, how is the pressure affected if I only need half the fuel (only using one stage of n20/fuel)?

Also you mentioned the pressue drop, I assumed there would be some sort of pressue drop like every fuel system. How severe did you mean? The two stages of nitrous are roughly a 150 shot a piece and staged 1500rpm apart. I went with a standalone to reduce the lean spikes/fuel rail requirements of a big intank setup, are the problems just less pronounced (smaller lean spike)?

Because my system is so similar to Dave's system pictured above, will prospective buyers have to set their pressure the same way? Is there an alternate method (possibly a different regulator) that allows you to set the pressue with out flowing it into a bucket?

I'm glad others are getting as much information from your posts as I am.