How big a shot will a 255LPH support???
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
How big a shot will a 255LPH support???
Thought you guys might could help on this one a little better than my C3 bretherens.
I got tired of listening to the holley whine so I went to an Edelbrock 255LPH in tank and a Mallory 3 port return regulator with 1 port capped, 1 to the carb, and 1 to the noid. All plumbing to and from is 6AN. Running 6 pounds of pressure. Currently set up as a 150 shot and does fine. How much further will these pumps support. My Cheater will go to 300, and I'm getting itchy since I put the Jacobs NMM in and found some traction.
I got tired of listening to the holley whine so I went to an Edelbrock 255LPH in tank and a Mallory 3 port return regulator with 1 port capped, 1 to the carb, and 1 to the noid. All plumbing to and from is 6AN. Running 6 pounds of pressure. Currently set up as a 150 shot and does fine. How much further will these pumps support. My Cheater will go to 300, and I'm getting itchy since I put the Jacobs NMM in and found some traction.
Last edited by EDDIEJ82; Aug 16, 2005 at 07:57 AM.
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
What... none of you guys running nitrous knows??? Cmon...help me out here.
Take a stab it it. I know most of yall with fuel injection run these pumps... how much will they support on fuel injection?
I know that pressure is a result of volume and restriction, and most of my volume is going back to the tank because I'm only running 6 psi, seems like I should be able to get away with a pretty big shot without running lean because of pressure drop.
These things are supposed to be running at 40 psi with fuel injection, aren't they?
Take a stab it it. I know most of yall with fuel injection run these pumps... how much will they support on fuel injection?
I know that pressure is a result of volume and restriction, and most of my volume is going back to the tank because I'm only running 6 psi, seems like I should be able to get away with a pretty big shot without running lean because of pressure drop.
These things are supposed to be running at 40 psi with fuel injection, aren't they?
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
The rule of thumb is that the 255lph can support around 600hp or so. It can probably do more, but I'm not going to be the one to find out for sure. Just don't go over 600 total hp and you should be ok (engine + nitrous).
I'm pretty sure the 255's that we run are a totally different pump. Ours are ment to be run on high pressure 40psi + makes a big difference if you're only running 6 psi.
I'm pretty sure the 255's that we run are a totally different pump. Ours are ment to be run on high pressure 40psi + makes a big difference if you're only running 6 psi.
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
Originally Posted by mn_vette
I'm pretty sure the 255's that we run are a totally different pump. Ours are ment to be run on high pressure 40psi + makes a big difference if you're only running 6 psi.
Racer
Joined: Dec 2004
Posts: 427
Likes: 0
From: Albuquerque New Mexico
I think for our fuel injection the fuel pump flow rate is only half the battle. The other half is how much flow the injectors will support. In this case, to go along with the 255 lph the neccessary injector size would be at least 42+ lbs.
FWIW, Your jet sizes will be the next kink in the line I believe with nitrous. Assuming there is enough fuel to support it, the 255 lph will be sending plenty of fuel for a 250+ shot of nitrous assuming your engine is making around 300 on motor only.
My nitrous experience is far from expert, and my overzealous application landed me with a blown motor on a 79' T/A. I would have a chat with a local tuner and see what their reccomendations are for the carb setup before bringing on more than a 200 shot.
-Dave
P.S. I'm a noob, just sharing my limited (and expensive) experience with nitrous.
FWIW, Your jet sizes will be the next kink in the line I believe with nitrous. Assuming there is enough fuel to support it, the 255 lph will be sending plenty of fuel for a 250+ shot of nitrous assuming your engine is making around 300 on motor only.
My nitrous experience is far from expert, and my overzealous application landed me with a blown motor on a 79' T/A. I would have a chat with a local tuner and see what their reccomendations are for the carb setup before bringing on more than a 200 shot.
-Dave
P.S. I'm a noob, just sharing my limited (and expensive) experience with nitrous.
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
Ok...maybe I'm thinking about this wrong.
My initial thought was... well if I'm only running 6 psi there should be an extra volume of fuel to up my shot drasticly, but the more I think about it... 600 HP is 600 HP no matter if the delivery sys is running at 40 psi or 6 psi. The total fuel comsumption to make 600 HP should be the same.
And if that's all the 255's will support, then I would only be able to up it 25-50 HP and be safe. DD say 519 on mine now NA, but I think it's very optimistic and with a perfect tune, in optimal conditions. I would guesstimate I'm putting out about 425-450 NA, so that doesn't leave me much room to play with. I don't really want to be the one to find out exactly how much these pumps can support before things go BOOM.
I was hoping some of you guys would have more practical experience running a 255 and nitrous, but I appreciate any opinions or input on the subject.
My initial thought was... well if I'm only running 6 psi there should be an extra volume of fuel to up my shot drasticly, but the more I think about it... 600 HP is 600 HP no matter if the delivery sys is running at 40 psi or 6 psi. The total fuel comsumption to make 600 HP should be the same.
And if that's all the 255's will support, then I would only be able to up it 25-50 HP and be safe. DD say 519 on mine now NA, but I think it's very optimistic and with a perfect tune, in optimal conditions. I would guesstimate I'm putting out about 425-450 NA, so that doesn't leave me much room to play with. I don't really want to be the one to find out exactly how much these pumps can support before things go BOOM.
I was hoping some of you guys would have more practical experience running a 255 and nitrous, but I appreciate any opinions or input on the subject.
Last edited by EDDIEJ82; Aug 16, 2005 at 08:47 PM.
Instructor
Joined: Mar 2005
Posts: 104
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It would appear that your reduction in pressure will increase your potential flow volume by around 28%. If you go to Aeormotive's website here: http://216.242.145.16/products/content_p.phtml?pk=11 you can read all about it.
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