Dropping fuel pressure on dyno
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Launching!
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From: Chesapeake, Virginia
Dropping fuel pressure on dyno I posted this in the fueling and injection section as well but as its a blower car I was hoping I could get the benifit of everyone elses experience here as well.
I have a 98 SS camaro, heads, cam and a procharger putting out 15 psi. The fuel system is a Walbro 255 in the tank with a MSD voltage booster and 60lb injectors, stock fuel lines. On the dyno trying to tune this under full boost the fuel pressure is dropping from 60psi to 40psi at about 4600 rpm and leaning out of a safe A/F. the car should be making around 600 rwhp. Is what I have enough? and if not what is needed? Any and all help is greatly appreciated as i would like to get this car to the track before it closes for the season.
I have a 98 SS camaro, heads, cam and a procharger putting out 15 psi. The fuel system is a Walbro 255 in the tank with a MSD voltage booster and 60lb injectors, stock fuel lines. On the dyno trying to tune this under full boost the fuel pressure is dropping from 60psi to 40psi at about 4600 rpm and leaning out of a safe A/F. the car should be making around 600 rwhp. Is what I have enough? and if not what is needed? Any and all help is greatly appreciated as i would like to get this car to the track before it closes for the season.
Look at longrange4u, 607rwhp on 42# injectors and 255lph with stock rails I believe. That was on a 67 trim turbo! I didn't even think 600+ was physically possible on 42's at 58psi fuel pressure, but he obviously did it, and it runs the number too...
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Launching!
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From: Chesapeake, Virginia
Originally Posted by bboyferal
I honestly don't think you have enough pump. One Walbro 255 shouldn't be enough for a tune for 15 psi of boost, especially with good flowing heads.
Are you on stock rails?
Are you on stock rails?
Yes it is still stock rails and stock lines. So how big of a pump should I get and by what company?
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Thread Starter
Launching!
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From: Chesapeake, Virginia
I did some searching around today and am looking at the Aeromotive 1000 pump that is supposed to support, 800 hp with a blower. this is a inline pump, so with that can just keep the 255 in the tank and put that inline with bigger fuel lines? I was looking at the line kit from Nasty Performance.
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Thread Starter
Launching!
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From: Chesapeake, Virginia
Originally Posted by Exotic Performance Plus
We have found dual in tank HP Walbros to be sufficient at the 600 rwhp level. Past that level and we have found larger fuel lines with a return style system need to be implemented. Bob
I am trying to figure out the balance between cost, ease of installation and abolute certainty that what i put in will work reliably in a street/strip car and not have to be upgraded again. I don't plan on doing anything more performance wise to this car.
I know my car is a C4 vette, but I drilled the bottom of the tank and used a bulkhead fitting towards the rear of the tank and then used the A1000 pump form aeromotive with -10 lines. our stock billet fuel rails are pretty good so they were modified with an fittings and a -6an return line was used.. pretty simple and straight forward setup.. if you use the A1000 pump you will want the billet fuel pump controller to reduce voltage at part throttle operation.. so far I have never looked back to my untrustworthy twin walbro setup.. I know alot of people use them without incident, but having a few lines blow off the top and the latest issue with bad pumps from the manufacturer and shotty warranty service, I am glad I went with the bigger pump..
the other nice thing is once you mod the fuel lines and such, if a larger pump is needed you can swap in the aeromotive eliminator pump which is the same physical dimensions very easily and sell the a1000.. made for a no brainer in my opinion.
Chris
the other nice thing is once you mod the fuel lines and such, if a larger pump is needed you can swap in the aeromotive eliminator pump which is the same physical dimensions very easily and sell the a1000.. made for a no brainer in my opinion.
Chris
Is it a steady drop or a rapid drop as soon as you hit 4600 rpm? Don't quote because I'm no expert, but if it's steady it might be your running out of fuel pump. Now if it a dramatic drop at 4600 rpm then it might be that your alternator is going bad which shuts off any power going to your pump right at 4600 rpms. I'm recently started experiencing this, but mine was dropping to 40 psi at 6000 rpms. I'm going to change out my autozone special alternator with a oem Ac Delco one... One other thing I started hearing noises here and there coming out of my alternator like a whine of bearings when all this started happening hope this helps...