NXL sucking the rails dry?
11-20-2003, 09:24 PM
#41
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I agree with 93LS1RX's theory. When the system is activated the fuel solenoid opens then needs to feed the "second rail" to feed the individual short fuel lines. It was very cool that CAT3 was able to log his runs, and according to his information it goes lean for .25 seconds, so it takes .25 seconds for the fuel system to "catch up" to the drop in pressure. I understand the concept behind the accumulator, but would it be able to react fast enough?
11-20-2003, 09:48 PM
#42
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Originally Posted by bad2000ss
I agree with 93LS1RX's theory. When the system is activated the fuel solenoid opens then needs to feed the "second rail" to feed the individual short fuel lines. It was very cool that CAT3 was able to log his runs, and according to his information it goes lean for .25 seconds, so it takes .25 seconds for the fuel system to "catch up" to the drop in pressure. I understand the concept behind the accumulator, but would it be able to react fast enough?
That being the case the accumulator doesn't need to "react" it will automatically balance the fuel pressure in the fuel rails.
11-20-2003, 09:53 PM
#43
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Originally Posted by CAT3
Mike, got it. takes some time to digest and put into nitrous flow for idiot terms, but the thought sunk in finally. I am curious as to this accumulator and its design. Better be able to hook it up neatly this NXL is just too damn pretty to be messing with.
11-20-2003, 10:14 PM
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spoke w/ my NX dealer, he's not sure on the NX design, but he realized the problem immediately, it's because of our returnless fuel system design....... He told me that some guy named joe lynch on corral.net had been messing around w/ such an idea for stangs (aparently some of them have a similar system)... so off I go into mustang land to do a little searching.
11-20-2003, 10:31 PM
#45
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Originally Posted by angst911
spoke w/ my NX dealer, he's not sure on the NX design, but he realized the problem immediately, it's because of our returnless fuel system design....... He told me that some guy named joe lynch on corral.net had been messing around w/ such an idea for stangs (aparently some of them have a similar system)... so off I go into mustang land to do a little searching.
11-20-2003, 11:14 PM
#46
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ok??? i might be playing devils advicate here but, it seems that if we are all agreeing that 93ls1rx's explanation is correct.......then why are some still talking about the accumulator? by 93ls1rx's account, it seems to me, the problem IS NOT THE FUEL, it is actually the n2o, due to it having to change from a gas to a liquid. so by this, i would think? that the challenge is not getting the fuel to the chamber faster, it is the n2o we need to catch up to the fuel. or am i looking at this bass ackwards? if so please explain.
11-21-2003, 12:06 AM
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The problem is indeed fuel -- want proof? Turn your bottle off, arm the system, and punch it... You'll notice the car loses power, then it comes back as the pressure returns (and of course then stumbles because of the excess fuel). If you have a fuel pressure gauge hooked up, you'll notice it drop, then return to normal.
If the regulator were on/near the fuel rail, we wouldn't experience this problem. A good regulator functions as an accumulator by design, and fills in when the fuel demand changes suddenly. Some regulator manufacturers actually mention this in their product descriptions
If the regulator were on/near the fuel rail, we wouldn't experience this problem. A good regulator functions as an accumulator by design, and fills in when the fuel demand changes suddenly. Some regulator manufacturers actually mention this in their product descriptions
11-21-2003, 12:48 AM
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Correct me if i'm wrong, but the NXL fuel rails have two "extra" ports on the front or back depending on how you decide to route the crossover. Would a dedicated fuel system be an alternative solution to the problem? It seems to me that NX should have seen this problem before hand, and if their accumulator solution is high priced perhaps a dedicated fuel system to feed to one of the extra ports would be a feasable option. The only other question would be how much more additional pressure would be needed from the second fuel system.
11-21-2003, 03:55 AM
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A dedicated fuel system or converting to a return-style would help ALL nitrous systems on our cars. Every nitrous kit I've worked with (NX, TNT, NOS, etc.) all experience a pressure drop on the initial hit. The returnless style fuel systems take a touch longer to recover though. The accumulator will definitely take care of that, and I'm betting it'll make the kit hit very sharp and crisp, just like if you had a dedicated fuel system for the nitrous kit.
11-21-2003, 06:21 AM
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Thanks Brains. The accumlator does not wait for the nitrous to activate it is basically going to back feed the rails ANY time the fuel pressure drops below whatever it is set for. If for instance you have it set for 50 psi you will never drop below say 48 psi. As the pressure in the rail drops below 50 the accumulator will start feeding the rail to get the pressure back up. It isnt going to be a long period of time that the accumulator needs to feed the rails.
Then when the pressure is high in the rails the rails feed the accumulator to keep it full and pressurized.
I have a fuel pressure regulator about 3 feet from the rails so I will let you know if mine has a hesitation. Right now I only have 4th gear cause my T56 is screwed but soon enough I will try it.
Then when the pressure is high in the rails the rails feed the accumulator to keep it full and pressurized.
I have a fuel pressure regulator about 3 feet from the rails so I will let you know if mine has a hesitation. Right now I only have 4th gear cause my T56 is screwed but soon enough I will try it.
11-21-2003, 12:55 PM
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The guys reply is in my work email, I'll post up as soon as I get back to work. Bust basically he said that you take a morosor oil accumulator, hook an air compressor up to it and fill it w/ about 20psi of air (maybe more for us since our fuel pressure runs higher than a mustangs maybe) and then hook the low side up to the fuel rail via as short of possible line being sure to mount the accumulator with the high side up... once I get back to work I'll post the entire conversation.
11-21-2003, 07:17 PM
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ok, here is the entire conversation, digest as you will, and um, you need to read bottom up:
Yep. Go to about 1/2 the normal pressure, or 29 psi. Then, when the engine is started, it will compress the air pocket to the normal pressure and fill the accumulator up about 1/2 full of fuel. This will help hold pressure as the fuel solenoid on the nitrous system opens and closes.
----- Original Message -----
From: Matt Johnson
To: 'Joe Lynch'
Sent: Friday, November 21, 2003 3:33 PM
Subject: RE: fuel question
Just thought of something, the ls1’s normall fuel pressure is 58PSI, would I need to add more pressure to the accumulator?
--------------------------------------------------------------------------------
From: Joe Lynch [mailto:joelynch@***.net]
Sent: Friday, November 21, 2003 12:37 AM
To: Matt Johnson
Subject: Re: fuel question
Matt--I believe the LS1s have a return built into the pump at the tank, just as you described. In that case, a local accumulator might help when the nitrous system hits. It doesn't really matter whether your system is a NOSzle type or a single Shark nozzle type, the fuel demand is the same. Since the fuel injectors and nitrous nozzles share the same fuel rail, adding a Moroso accumulator would work well. You will need the Moroso accumulator, check the Summit or Jegs web site. then use a -6AN hose and connect it to the taps in your new fuel rails.Try to keep the line from there to the accumulator short, but you will have to mount the accumulator so that the valve end is the high point and the fuel connection is low. You will have to get some fittings to hook up the -6AN lines at each end. Put 20 psi air in it with the engine off. Then go see if it helps.
You really need to data log the fuel pressure during a run to see if you did any good or not.
You may need a bigger fuel pump if the fuel pressure is dropping off any near your window switch max setting.
Joe
----- Original Message -----
From: Matt Johnson
To: 'Joe Lynch'
Sent: Thursday, November 20, 2003 11:09 PM
Subject: RE: fuel question
So you added a return line to your system, interesting, not sure how I would go about that. I know that some people manage to install FP regulators in our vehicles (4th Gen LS1 f-bodies) but not how, I think there is a return line, but it doesn’t come to the front of the car, just splits off at a T around the pump, would need to investigate more. I’m installing a NX NXL DP kit. If you haven’t seen ‘em, it includes new fuel rails, and sleeves which your injectors fit in to allow DP w/o tapping the intake manifold, very slick setup. The problem we believe we are seeing is that when the nitrous hits, it takes a second for the solenoids and fuel lines to the jets to fill up, and we are loosing pressure in the rails, which means no fuel for the injectors either. I’ve heard NX is coming out w/ some sort of accumulator that would bolt to the back of the rails (the rails have tap ports on front and back, both sides, but one set is used for a crossover tube), but now one knows when that will be coming around, so I’m trying to find a solution to this before something bad happens. DO you have any ideas on this? Or as to how a accumulator could be hooked up to stabilize the pressure?
--------------------------------------------------------------------------------
From: Joe Lynch [mailto:joelynch@***.net]
Sent: Thursday, November 20, 2003 11:59 PM
To: Matt Johnson
Subject: Re: fuel question
Matt--
I am running a wet NX kit. On my car and all 99 plus Fords, the computer adjusts pump speed to hold fuel pressure. This works fine on an all motor car, because the fuel demand doesn't change instantaneously. It changes relatively slowly compared to the speed of the fuel pressure controller in the computer. That changes with a nitrous system. The nitrous system requires a step change in fuel flow to match the opening of the nitrous solenoid. This is true really whether the nitrous system is a wet kit or a dry kit. When the nitrous flows, the fuel demand changes instantaneously. If the fuel flow lags, there is a short term lean condition until the fuel pressure controller gets the pump sped up to match the demand.
Then you shift. The nitrous flow stops, the fuel demand stops, but the comptuer can't slow the pump down until too late--the fuel pressure spikes.
I took a small oil accumulator marketed by Moroso, teed it into the fuel line, put 20 psi in it with an air hose, and then started up the engine. The air compresses until it is at 39 psi or so. The fuel pressure changes slower with the accumulator, and takes out some of the spikes.
But what really works best is to add a mechanical regulator and a return line, then lie to the computer about what the fuel pressure is so that the computer will speed the pump up to full speed and the mechanical regulator will take the swings in fuel demand as the fuel demand changes with the nitrous solenoid opening and closing. I do this with an electronic fuel pressure controller from Zone V Performance. The mechanical works better than having the accumulator, but I haven't tried the accumulator AND the regulator. That may be the best system of all.
Hope that helps. Let me know if you have any questions. I'm still working on it, but I have it pretty close now.
Joe Lynch
Midland, TX
----- Original Message -----
From: Matt Johnson
To: joe@joelynch.org
Sent: Thursday, November 20, 2003 10:26 PM
Subject: fuel question
Hi, I was asking around and heard you had tried to design some sort of accumulator system for the returnless fuel system in your stang. Some of us GM guys have recently been running into a similar system w/ our returnless fuel systems. I was wondering if you could share you experience w/ trying to get around the pressure drops that the returnless systems experience. Thanks.
----- Original Message -----
From: Matt Johnson
To: 'Joe Lynch'
Sent: Friday, November 21, 2003 3:33 PM
Subject: RE: fuel question
Just thought of something, the ls1’s normall fuel pressure is 58PSI, would I need to add more pressure to the accumulator?
--------------------------------------------------------------------------------
From: Joe Lynch [mailto:joelynch@***.net]
Sent: Friday, November 21, 2003 12:37 AM
To: Matt Johnson
Subject: Re: fuel question
Matt--I believe the LS1s have a return built into the pump at the tank, just as you described. In that case, a local accumulator might help when the nitrous system hits. It doesn't really matter whether your system is a NOSzle type or a single Shark nozzle type, the fuel demand is the same. Since the fuel injectors and nitrous nozzles share the same fuel rail, adding a Moroso accumulator would work well. You will need the Moroso accumulator, check the Summit or Jegs web site. then use a -6AN hose and connect it to the taps in your new fuel rails.Try to keep the line from there to the accumulator short, but you will have to mount the accumulator so that the valve end is the high point and the fuel connection is low. You will have to get some fittings to hook up the -6AN lines at each end. Put 20 psi air in it with the engine off. Then go see if it helps.
You really need to data log the fuel pressure during a run to see if you did any good or not.
You may need a bigger fuel pump if the fuel pressure is dropping off any near your window switch max setting.
Joe
----- Original Message -----
From: Matt Johnson
To: 'Joe Lynch'
Sent: Thursday, November 20, 2003 11:09 PM
Subject: RE: fuel question
So you added a return line to your system, interesting, not sure how I would go about that. I know that some people manage to install FP regulators in our vehicles (4th Gen LS1 f-bodies) but not how, I think there is a return line, but it doesn’t come to the front of the car, just splits off at a T around the pump, would need to investigate more. I’m installing a NX NXL DP kit. If you haven’t seen ‘em, it includes new fuel rails, and sleeves which your injectors fit in to allow DP w/o tapping the intake manifold, very slick setup. The problem we believe we are seeing is that when the nitrous hits, it takes a second for the solenoids and fuel lines to the jets to fill up, and we are loosing pressure in the rails, which means no fuel for the injectors either. I’ve heard NX is coming out w/ some sort of accumulator that would bolt to the back of the rails (the rails have tap ports on front and back, both sides, but one set is used for a crossover tube), but now one knows when that will be coming around, so I’m trying to find a solution to this before something bad happens. DO you have any ideas on this? Or as to how a accumulator could be hooked up to stabilize the pressure?
--------------------------------------------------------------------------------
From: Joe Lynch [mailto:joelynch@***.net]
Sent: Thursday, November 20, 2003 11:59 PM
To: Matt Johnson
Subject: Re: fuel question
Matt--
I am running a wet NX kit. On my car and all 99 plus Fords, the computer adjusts pump speed to hold fuel pressure. This works fine on an all motor car, because the fuel demand doesn't change instantaneously. It changes relatively slowly compared to the speed of the fuel pressure controller in the computer. That changes with a nitrous system. The nitrous system requires a step change in fuel flow to match the opening of the nitrous solenoid. This is true really whether the nitrous system is a wet kit or a dry kit. When the nitrous flows, the fuel demand changes instantaneously. If the fuel flow lags, there is a short term lean condition until the fuel pressure controller gets the pump sped up to match the demand.
Then you shift. The nitrous flow stops, the fuel demand stops, but the comptuer can't slow the pump down until too late--the fuel pressure spikes.
I took a small oil accumulator marketed by Moroso, teed it into the fuel line, put 20 psi in it with an air hose, and then started up the engine. The air compresses until it is at 39 psi or so. The fuel pressure changes slower with the accumulator, and takes out some of the spikes.
But what really works best is to add a mechanical regulator and a return line, then lie to the computer about what the fuel pressure is so that the computer will speed the pump up to full speed and the mechanical regulator will take the swings in fuel demand as the fuel demand changes with the nitrous solenoid opening and closing. I do this with an electronic fuel pressure controller from Zone V Performance. The mechanical works better than having the accumulator, but I haven't tried the accumulator AND the regulator. That may be the best system of all.
Hope that helps. Let me know if you have any questions. I'm still working on it, but I have it pretty close now.
Joe Lynch
Midland, TX
----- Original Message -----
From: Matt Johnson
To: joe@joelynch.org
Sent: Thursday, November 20, 2003 10:26 PM
Subject: fuel question
Hi, I was asking around and heard you had tried to design some sort of accumulator system for the returnless fuel system in your stang. Some of us GM guys have recently been running into a similar system w/ our returnless fuel systems. I was wondering if you could share you experience w/ trying to get around the pressure drops that the returnless systems experience. Thanks.
11-22-2003, 12:13 PM
#55
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Originally Posted by angst911
I think the same concept would apply, just we would need a little bit more pressure in the accumulator than the mustangs do....
I wish someone from NX or someone who knows could chime in and give us an ETA on when we could buy this thing. Maybe Dave from Nitro Dave's would know when this might be available.
11-22-2003, 03:54 PM
#56
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Yes they do have it completed. Call Nitrous Express and talk to Brook or Ricky. They are the 2 really good people there. Ricky is teh designer of the NXl system and I believe the GM.
He is more than willing to tell you about all there upcoming stuff.
Dave may also know.
He is more than willing to tell you about all there upcoming stuff.
Dave may also know.
