Custom Fuel System Review

[99-LS1-SS]

Custom fabricated fuel system.

Brand: Various
Price: $950
Purchased From: (URL) Ktlplxm (http://forum.grrrr8.net/member.php?611-Ktlplxm) Aden


Installation: Involved
Installation Time: Weekend
Any Installation Tips You Have: I have never done a fuel system on a car so I opted to have Aden do it. If you have experience with fuel systems then you can probably do this.

Quality of Part: 10
Product Performance: 10
Would you Recommend to Others:I would recommend this to anyone looking to be able to supply more fuel to your car.

Any Other Comments: This is my first experience with a custom fuel system. There are trade offs with this modification as there are with most. If you know the trade offs going in you'll be better prepared to know what to expect. The only real negative trade off is that you have to wait for your pumps to prime the system upon startup which usually takes ~4 seconds (on my system anyway). You can't just get in the car and turn the key immediately or you'll just spin the motor. This is something that I have to reteach myself.

You will most likely need larger injectors when you perform this upgrade. My car had LS9 injectors. Whichever injector you choose you WILL NEED TO ADJUST YOUR TUNE to the new injector data for this system to work properly. If you skip this step don't bitch about the car not running right. I can give tips and observations that I made to anyone that wants them regarding tuning your car for this fuel system.

Currently I'm using the stock line (-6 line) from the gas tank to the fuel rail. If you want to push your car above 650 rwhp then you will likely need to increase the size of that line to a -8 line.

A basic overview of the system:

Twin intank Walbro 342 fuel pumps. A -8 line (1/2" diameter) coming out of the tank going to the pressure regulator. A -6 (3/8" diameter) line coming out of the regulator and tying into the factory metal line going up to the fuel rail. There is also a -6 return line going from the regulator back into the tank. The regulator is adjustable. Mine is set to 58 psi (stock fuel system psi). This system runs on one fuel pump until 4 lbs of boost is reached and the second pump is activated via a hobbs switch. I believe you can have your pumps come in at different lbs of boost depending on the hobbs switch that you use. Aden can confirm one way or the other.

One work of caution, if you upgrade to this system do not skimp on lines or try to reuse any none metal lines. They will rupture....ask me how I know....

[Ktlplxm]

Brandon, I'm glad you are happy with this particular set-up. If you have any other questions or want to modify anything late on it, feel free to give a call anytime!!

[wreckwriter]

Price is better than I expected. bet the install is a motherfucker though....

[vic2186]

I saw the GM hightech also it's by vengeance a surge tank with duel Bosch 44 pumps and lines and fittings looks sick but $$$ ??anyone know the price

[wreckwriter]

I saw the GM hightech also it's by vengeance a surge tank with duel Bosch 44 pumps and lines and fittings looks sick but $$$ ??anyone know the price

Nope, and they didn't answer my email.

[Tempest2000]

Is this the kit you (ktlplxm) were working on with the guy on ls1tech or is this something else?

[99-LS1-SS]

If you are going forced induction then you might want to consider upgrading your fuel system. The system I have should support up to 650 rwhp which is as much or more than the engine can handle in its stock form.

I've updated the first post to give a little more detail.

[Tempest2000]

Hmm thats a lot cheaper than what I was quoted for the same basic setup elsewhere. Might have to give Aden a shout...

[Ktlplxm]

The fuel system is the same BASIC components as what I did in my vehicle. The differences are the size of the lines, the orientation of the lines, and the layout of the fuel system. Brandon's will be good to 600-650 whp. With upgraded lines his same system can be used to feed up to 900-1000 hp. This system had not been published by anyone else, in any other magazine. The Vengeance System uses a "surge" or secondary tank design. The system as it sits in brandons car can be sold for approximately what he quoted. Any additional changes such as line size or location can change the price of the kit from 100-300 dollars; still a far cry from some of the systems people have reported. In my vehicle both the feed and return lines are aftermarket for increased capacity, and have passed my testing for fuel delivery (several quarter mile passes as well as a long pull to 184mph). the install is only as difficult as the installer makes it. It will require dropping the tank, and making adequate clearance under the passenger seat. In both of our vehicles I made an access port under the seat. If anyone is interested in the system feel free to give me a call or send a Pm. The system will require the you supplying fuel pump or a core charge to cover one of the pumps which I would supply. Different materials could also change the price of the kit, although I would only recommend one type of line for the "picky" buyer. Hope to hear from you soon.

Aden (ktlplxm)

[1ChargedG8]

Can anyone provide pictures of this setup?

[Ktlplxm]

Of which part? The pumps are in the tank, so you can't see them, and the underhood area remains stock appearing. Everyones set up will look different depending on how and where they run the lines. As far as pictures of the pump assembly itself, I do not share pics of it due to the fact many unscrupulous people would seek to copy it. That is an agreement I made with the pump builder, which I wholeheartedly agree with and standby. If there are other specific pictures you would like, just ask and ill provide what I can

[1ChargedG8]

i was actually looking for pics of the pumps assembly but i understand if you don't want to provide them... i was just curious....

[1ChargedG8]

also, can this setup support E85?

[Ktlplxm]

I will have to look at the materials in the lines. It may be possible to build an e85 set up, but I am not sure how it would affect the price. Additionally, the buyer would have to to verify injector compatibility

[norm8332]

How do the pumps prime? You just turn the key to on (not start) for four seconds, then start?

This could be a downside because remote start may not work correctly.

Looks like a great system. I'm definitely following this.:)

[Ktlplxm]

Correct the pump(s) prime when the key is turned forward. Because u are converting to an adjustable pressurfe system. The regulator relieves the pressure in the lines. You just have to repressurize it. With smaller lines it happens quickly. Larger lines hold a ton more fuel so it takes an extra second or so to prime

[99-LS1-SS]

How do the pumps prime? You just turn the key to on (not start) for four seconds, then start?

This could be a downside because remote start may not work correctly.

Looks like a great system. I'm definitely following this.:)

Yes Norm, the pumps prime when you turn the key on.

I have my prime time set to 16 seconds. The reason for this is the system takes around 4 second to fully pressurize, and then you want there to be a continuous feed of fuel and pressure during the cranking cycle. Once the engine is running the prime cycle is automatically cut off so the length of time you have the prime set for doesn't matter, as long as it isn't too short.

I had mine set to 6 seconds originally and I would let it prime and cut off and when I would turn the key to crank it the pumps have to re-pressurize the lines while attempting to crank the engine so it would take 5 to 7 revolutions to startup.

[Ktlplxm]

Its one of trade offs we all have to make for power lol. Brandon doesn't have remotestart so we can't test his, but mine still works

[Ktlplxm]

Maybe someone like chris can hack the remotstart programming and alter the cycle time

[Tempest2000]

While I like the remote start I could learn to live without it. Since my seat heaters have high, higher, and burn my azz settings it doesn't take long to get warm lol

[MaxPower]

Correct the pump(s) prime when the key is turned forward. Because u are converting to an adjustable pressurfe system. The regulator relieves the pressure in the lines. You just have to repressurize it. With smaller lines it happens quickly. Larger lines hold a ton more fuel so it takes an extra second or so to prime

Not sure I follow... A regulator doesn't "relieve" pressure in the lines, it has an adjustable diaphram that (based on the input screw and amount of force the spring exerts on that diaphram) "holds-back" pressure behind it to keep a constant pressure in the rails. If you run the vehicle then shut it down, the diaphram still will try to maintain pressure behind it. Typical Walbro pumps have an internal check valve (and pressure relief valve) that will keep pressure from bleeding back into the tank - combined with a FPR after the rails, should maintain some pressure in your rails after key is off.

Lots of manufacturers using stock or even adjustable regulators still hold some pressure in the lines, and don't take 4 seconds to pressurize. My Lightning, with a larger tank, FPR and pair of Walbro 255's (I think they were GS340s?) didn't take 4 seconds to pressurize. You would hear the pumps kick in for a very short second to pressurize the lines, no need to wait for the lines to pressurize any more than that. There's always some gasoline in the lines.

How much pressure is bled off after you turn the key off? Does it drop down to 0 immediately? It's not like we have giant fuel lines that would require more pump to fill them after sitting overnight/few hours, etc.

Just trying to figure out where the issue is that would cause a long delay before start. :uhm:

[Ktlplxm]

An aftermarket regulator does not have a spring controlled seat like a factory style does. The factory regulators work with a fixed tension spring (not a true regulator, more like a spring loaded cap) that is opened at certain psi, thereby relieving any excess pressure (above what the manufacturer had deemed adequate) and closing again once the pressure drops below its rating. This also works to relieve pressure once the vehicle is off. Engine temperatures "cook" the rails. When heat is applied to a liquid it expands. as it expands in a "closed" area pressure builds. If the spring loaded actuator didnt open to relieve the system after it was off, the nylon lines would eventually burst due to the increased pressure. I can assure you, the regulator does in fact "relieve" pressure. Almost all aftermarket regulators however, utilize a, for lack of a better word, a needle and seat design where a fixed orifice never fully closes and a needle or plunger regulates the amount of fuel bypassed (one of the reasons a regulator set at a pressure on one car has a different pressure when installed on another car). Because the orifice is never closed, pressure is always relieved. If the spring/adjusting screw/diaphragm regulators were readily available they would function somewhere between the two. Unfortunately, most companies have gotten away from the diaphragm design, Aeromotive being one of the first to ditch it. Relieving pressure doesn't mean you loose volume, just the pressure. Comparing it to your Lightning system or an Fbody system is comparing apples to oranges. Neither of those vehicles works off of an internal venturi system that pulls fuel from two sides of the tank. With the pumps being run in series with one another, not in parallel then feeding into a single line, the usual rules do not apply. Another angle to consider are the pressures used in the systems. I'm not 100% sure of the Lightnings pressure, but very few other vehicles run the pressure a Gen4 engine does. Most of them fall into the 35-45 psi range versus 60psi. Factor that in along with the injector sizes we are dealing with (60lbers) and it is easy to see how the pressure will not climb as fast as it does in other vehicles. Furthermore, during cranking we are not using both pumps. Using bith would create a huge "draw" on the starting systems. The G8's have shown to be extremely sensitive to voltage drops, which is an issue for someone with more electrical knowledge than I to explain. The final thing to consider is the regulator placement. With the regulator mounted at the rail, the fixed orifice is well above the tank level. When the vehicle is turned off, fuel "bypass" can become a siphon point. Residual pressure keep a small "current or flow" back to the tank. Throw gravity, atmospheric pressure, and the small amount of suction left in the tank, in to the into the equation and you create a siphon effect. Almost everyone remembers the high school physical science lessons (or for that matter siphoning fuel out of a fuel tank). All you have to do is introduce a small amount of suction for a short time and it will evacuate a good deal of the available volume. I hope this explanation helps explain the situation a little better. If there are any other question or concerns, please ask.

[MaxPower]

I knew our systems were a lot different in the way it was designed. Good information to retain for the future.

60psi is a lot of base pressure. I guess I took it as you were saying that a FPR only relieves pressure. I guess looking at it both ways it relieves or allows the system to 'build' as well.

Thanks for the extra info!

[Ktlplxm]

No problem

[SFC]

At what point do the stock fuel rails need to be swapped (if at all)? As for e85, I think people wayyy over-analyze it. Stock injectors/lines can handle it on pretty much any new car, you just need the ability to flow more fuel and have it tuned properly.

[SFC]

Also, any issues with fueling if the tank is low? I thought that was the primary concern with doing the drop-in setup?

[99-LS1-SS]

No issues that I have encountered with a low tank. I've only had it below a 1/4 of a tank once. I don't like to do that on any car that I own. I've run out of gas and had to walk a long way before so I'll put gas in the tank before it gets to 1/4 of a tank.

[VegasNate]

Thanks for the write up. I'm sending my pump in this week to Lonnie. Sounds like the best way to go.

[Ktlplxm]

At what point do the stock fuel rails need to be swapped (if at all)? As for e85, I think people wayyy over-analyze it. Stock injectors/lines can handle it on pretty much any new car, you just need the ability to flow more fuel and have it tuned properly.
Can they handle it? Probably. Is anyone willing to stick there neck out and guarantee it? Probably not. I never plan on using it till I'm forced to (no real benefit to me) so I'm not testing it.


Also, any issues with fueling if the tank is low? I thought that was the primary concern with doing the drop-in setup?
I haven't had any low level fuel problems in mine since September/October when it was done. For a little while I thought I did but it was a faulty level sender. the tank was reading between 1/8-1/4 and I would run out. I realized it wasnt the pump when we intentionally ran it out of gas then trailered it to the store down the road. It took almost a full 19 gallons to fill it. In comparison, I ran the vehicle out of fuel when it was three weeks old just to see what the full range was... it only took 18.5 that time, so the low fuel shouldnt be an issue. Having said that, no one should ever race with the fuel level below a 1/4 tank anyway.

[Ktlplxm]

Thanks for the write up. I'm sending my pump in this week to Lonnie. Sounds like the best way to go.

you should be very happy with it. If you go with -8 lines remember to have you fuel prime cycle maxed out; it takes a little bit to fully pressurize the system to 60lbs with that large of lines

[VegasNate]

An aftermarket regulator does not have a spring controlled seat like a factory style does. The factory regulators work with a fixed tension spring (not a true regulator, more like a spring loaded cap) that is opened at certain psi, thereby relieving any excess pressure (above what the manufacturer had deemed adequate) and closing again once the pressure drops below its rating. This also works to relieve pressure once the vehicle is off. Engine temperatures "cook" the rails. When heat is applied to a liquid it expands. as it expands in a "closed" area pressure builds. If the spring loaded actuator didnt open to relieve the system after it was off, the nylon lines would eventually burst due to the increased pressure. I can assure you, the regulator does in fact "relieve" pressure. Almost all aftermarket regulators however, utilize a, for lack of a better word, a needle and seat design where a fixed orifice never fully closes and a needle or plunger regulates the amount of fuel bypassed (one of the reasons a regulator set at a pressure on one car has a different pressure when installed on another car). Because the orifice is never closed, pressure is always relieved. If the spring/adjusting screw/diaphragm regulators were readily available they would function somewhere between the two. Unfortunately, most companies have gotten away from the diaphragm design, Aeromotive being one of the first to ditch it. Relieving pressure doesn't mean you loose volume, just the pressure. Comparing it to your Lightning system or an Fbody system is comparing apples to oranges. Neither of those vehicles works off of an internal venturi system that pulls fuel from two sides of the tank. With the pumps being run in series with one another, not in parallel then feeding into a single line, the usual rules do not apply. Another angle to consider are the pressures used in the systems. I'm not 100% sure of the Lightnings pressure, but very few other vehicles run the pressure a Gen4 engine does. Most of them fall into the 35-45 psi range versus 60psi. Factor that in along with the injector sizes we are dealing with (60lbers) and it is easy to see how the pressure will not climb as fast as it does in other vehicles. Furthermore, during cranking we are not using both pumps. Using bith would create a huge "draw" on the starting systems. The G8's have shown to be extremely sensitive to voltage drops, which is an issue for someone with more electrical knowledge than I to explain. The final thing to consider is the regulator placement. With the regulator mounted at the rail, the fixed orifice is well above the tank level. When the vehicle is turned off, fuel "bypass" can become a siphon point. Residual pressure keep a small "current or flow" back to the tank. Throw gravity, atmospheric pressure, and the small amount of suction left in the tank, in to the into the equation and you create a siphon effect. Almost everyone remembers the high school physical science lessons (or for that matter siphoning fuel out of a fuel tank). All you have to do is introduce a small amount of suction for a short time and it will evacuate a good deal of the available volume. I hope this explanation helps explain the situation a little better. If there are any other question or concerns, please ask.

My head hurts...What about some kind of check valve to keep the fuel from siphoning out of the lines. My system is going in next week probably.

[Ktlplxm]

Where u gonna put it?

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[VegasNate]

Where u gonna put it?

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I don't know! lol Thats why I'm asking.

[Tempest2000]

I guess you are saying that something like this wouldn't work if it was close to the tank to keep the pressure?
http://www.holley.com/251008ERL.asp

Here is one suggestion I found on a corvette forum...

If you are having a hard start issue due to fuel pressure then just wire a seperate fuel pump relay that stays on with the ignition rather than cycles like most. It still wouldn't solve the remote start issue unless you could delay the ignition, but it would keep you from cycling the key twice if it takes longer than the 3 second prime.

[Ktlplxm]

Wont work. Tried it once. Epic Fail.

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[Darkmanx]

pics of the system installed and uninstalled?

[Ktlplxm]

not really anything to "show". Before and after pictures of the tank look the same pretty much, and the engine bay would be different for every user. I will not take pictures of the pump set-up in the canister because it is Lonnie's Design and property. If he would like to show it that is fine, but there are too many unscrupulous people who would try to rip him off by copying what he spent so much time designing. I may have some pics of the engine bay of my car before I changed the direction it was going...

[Ktlplxm]

First a 2300 Maggie. Twin Fuel Pump system, RotoFab (notice the feed line is still stock appearing):
http://i210.photobucket.com/albums/bb222/ktlplxm/maggierotofabbrandon.jpg

another 2300, Twin Pump, RotoFab, stock lines
http://i210.photobucket.com/albums/bb222/ktlplxm/1018091855.jpg

FAST Intake and rails, -8 Feed line from the Tank, Rear -6 Crossover Line, -6 Return line to the Aeromotive regulator (not pictured), -6 Return to the Tank
http://i210.photobucket.com/albums/bb222/ktlplxm/a383e49b.jpg