Calling the nitrous pros...again
Thread Starter
Racer
Joined: Jul 2004
Posts: 420
Likes: 1
From: Lapeer MI
Calling the nitrous pros...again
I am installing a NOS cheater system on my ZZ502. My current fuel pump set-up uses a Holley pump 125 gal/hr (this pump). I don't have a return line. I believe it's called a dead head fuel set-up.
The cheater kit has nitrous jets to provide up to 250HP. I have a two stage system and am looking to spray about 200HP with the second stage active. The 502 produces 502 max HP. With nitrous I'm looking at 700HP which Holley claims the pump can handle.
Does anyone see a problem with my current set-up?
Where does everyone have their fuel pressure safety switch located?
How do I know which psi switch is correct for my application? I purchased a 5 psi switch. All 3 books I read don't say which psi switch to use.
The cheater kit has nitrous jets to provide up to 250HP. I have a two stage system and am looking to spray about 200HP with the second stage active. The 502 produces 502 max HP. With nitrous I'm looking at 700HP which Holley claims the pump can handle.
Does anyone see a problem with my current set-up?
Where does everyone have their fuel pressure safety switch located?
How do I know which psi switch is correct for my application? I purchased a 5 psi switch. All 3 books I read don't say which psi switch to use.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
First off....I doubt that pump is big enough....they are usually a little optimistic on the HP ratings that they can support....
Secondly, what size fuel line is the entire system? If it is not ATLEAST -8 all the way from the tank I wouldn't chance it....-10 to the engine would be better, then T off a -6 to the fuel solenoid.
Third, make sure you set your fuel pressure for the fuel solenoid FLOWING....usually 5 psi flowing is what you want....some people set up at 5 psi dead headed then hit the button and the pressure drops to 2 psi or less and they melt stuff and can't figure out why.....
Just do your homework on it...keep the timing conservative and start out on a small shot and work your way up....
Also hit up 69' NoxRat he is the nitrous guru here....
Secondly, what size fuel line is the entire system? If it is not ATLEAST -8 all the way from the tank I wouldn't chance it....-10 to the engine would be better, then T off a -6 to the fuel solenoid.
Third, make sure you set your fuel pressure for the fuel solenoid FLOWING....usually 5 psi flowing is what you want....some people set up at 5 psi dead headed then hit the button and the pressure drops to 2 psi or less and they melt stuff and can't figure out why.....
Just do your homework on it...keep the timing conservative and start out on a small shot and work your way up....
Also hit up 69' NoxRat he is the nitrous guru here....
Thread Starter
Racer
Joined: Jul 2004
Posts: 420
Likes: 1
From: Lapeer MI
Ajrothm,
Thank you very much for the reply. I just want to make sure I get this right....
The inlet/outlet of the pump is -6. Upgrading to -8 will lower the friction in the line but the pump will still be a bottleneck.
How do I do that?
Typically, at wide open throttle, full power, an engine requires 0.5 lbs. of fuel per horsepower every hour. A gallon of gasoline weighs approximately 6 lbs. Therefore an engine rated at 700 horsepower will require about 350 pounds (58 gallons) of fuel every hour.
(700HP x .5 lbs = 350 lbs of fuel
350 lbs/6 lbs = 58 gallons per hour)
This pump will flow 110GPH at 7.0 PSI but I only require 58.
Thank you very much for the reply. I just want to make sure I get this right....
How do I do that?
Typically, at wide open throttle, full power, an engine requires 0.5 lbs. of fuel per horsepower every hour. A gallon of gasoline weighs approximately 6 lbs. Therefore an engine rated at 700 horsepower will require about 350 pounds (58 gallons) of fuel every hour.
(700HP x .5 lbs = 350 lbs of fuel
350 lbs/6 lbs = 58 gallons per hour)
This pump will flow 110GPH at 7.0 PSI but I only require 58.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Trust me.... That engine will need more then 58gph...that is about a rating for a stock fuel pump....by your math, your 110gph pump should be good for 1400hp? Not even close...
A 110gph pump is probably fine for 500hp....I wouldn't try to spray with that pump.....maybe a 100hp shot....maybe...
Many many years ago I did use a Holley Blue that was like 110gph I believe on a 400hp or so 406" Pontiac and had a 150hp shot on it and never had a problem but....I am sure it was on the edge...and that pump had 1/2" lines to and from it.
Just do your homework.....search nitrous forums and speedtalk.com for info....I believe you are highly under estimating the fuel needs for 700hp....especially since 200 of it is nitrous which requires instant volume and pressure.
As for the lines... -6 is equal to 3/8".....I doubt that will feed 700hp
for reference, my 172gph mechanical pump has a -10 inlet and -8 outlet from the factory....it is rated for 700hp if using -10 line to feed it....
A 110gph pump is probably fine for 500hp....I wouldn't try to spray with that pump.....maybe a 100hp shot....maybe...
Many many years ago I did use a Holley Blue that was like 110gph I believe on a 400hp or so 406" Pontiac and had a 150hp shot on it and never had a problem but....I am sure it was on the edge...and that pump had 1/2" lines to and from it.
Just do your homework.....search nitrous forums and speedtalk.com for info....I believe you are highly under estimating the fuel needs for 700hp....especially since 200 of it is nitrous which requires instant volume and pressure.
As for the lines... -6 is equal to 3/8".....I doubt that will feed 700hp
for reference, my 172gph mechanical pump has a -10 inlet and -8 outlet from the factory....it is rated for 700hp if using -10 line to feed it....
Racer
Joined: Oct 2009
Posts: 441
Likes: 2
From: San Antonio TX
I don't like " dead heading " the pump either...you can always run a regulator and dump back into the suction side....I've done this on my 454 & 8/71 ...but I'm also running 2 Mallory Pro-Comp 250's
ps...everyone I know that runs Nitrous has seperate pumps ..1 to the carb , 1 to the Nitrous
ps...everyone I know that runs Nitrous has seperate pumps ..1 to the carb , 1 to the Nitrous
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Btw I used to lay the nitrous plate in a 5 gal bucket and activate the fuel solenoid and let it fog the bucket while I adjusted the fuel pressure...set it with the correct jetting for the shot you want...
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