Chevy Impala SS Forum banner
1 - 20 of 26 Posts
G

·
Discussion Starter · #1 ·
How much hp can you make and still use a stock-style fuel pump? I installed a Walbro 255 and dont know if I'll have enough fuel to supply my combo. Have an LT1 383 with approx 425hp plus 150 to 200 shot of spray. Runs great NA but don't want to lean out as I step-up the spray.
Any proven combos?
 
G

·
Discussion Starter · #2 ·
Your engine probably is close enough to my 383 natural combo. My Walbro in tank could not supply the fuel rail with enough fuel by around 1/2 track the nitrous fuel solinoid would suck the fuel rail dry and the hobbs safety switch would turn off the nitrous.

You can add fuel supply many ways. The way I did it was a small fuel tank in the engine bay with a small high pressure "efi" in line fuel pump and an Aeromotive reglator hooked directly into the nitrous fuel supply solinoid. It cost some bucks but it sure is reliable.
 
G

·
Discussion Starter · #3 ·
I'm running the Walbro 255 with my 383 and 150 shot. I seem to be fine for fuel, since the last Mustang dyno run I did I was running super rich blowing black clouds of smoke out. Fuel pressure stayed at 43psi. I added a Kenne-Bell boosta pump just incase I need more volume though. I'm currently running it at 15volts.
 
G

·
Discussion Starter · #4 ·
Tom even before that weren't you running a Racetronix relay kit? Wonder if Karl only had issues due to stock tiny wiring?
If spraying a modded motor a good relay kit would definetely be worthwhile just to make sure you are getting the most out of your existing fuel pump, by the time you begin to spray a nice stroker I am sure it is required.
 
G

·
Discussion Starter · #5 ·
man the forum is whacko today. I posted a reply here early this morning and it has vanished. so again.

That is a good and quick fix that Tom mentioned....the increasing fuel pump voltage. It worked for me but it was just barely enough fuel. The longterm fix was a separate pump and fuel supply.

Again, there are a bunch of other ways to do this such as add an inline fuel pump to the stock system, tap and add another line, pump, filter, into the stock tank. Put 2 intank pumps into the stock tank like Stonebreaker did. etc.

Nitrous fuel enrichment system is what the system that I added is officially called. Try a google search on that. it's makes things pretty reliable and you can put high test gasoline in the small tank.

Karl
 
G

·
Discussion Starter · #6 ·
Good info. I like the idea of 2 pumps. I considered running one big Aeromotive A1000, but without a speed controller, I heard it will heat-up the fuel too much. $560 Overkill for street?
1. If I make a seperate fuel system, how many gallons of race fuel are recommended (tank size)?
2. Should I also run 2 fuel pressure safety switches in series? One for the engine fuel and one for N2O fuel...?
A dual fuel system makes sense, esp when driving the car to the track. 93 octane in the big tank and race fuel in the N2O fuel tank.
 
G

·
Discussion Starter · #7 ·
1/2 gal. or even smaller tank is all that is needed for the nitrous system gasoline.
Hobbs for the nitrous fuel system line certainly but another for the stock fuel system is a maybe. Maybe it's worth it or maybe it's just adding complications.
The overall goal is simplicity for reliability yet maximizing safety. Some like a lot of wires and switches and safety gadgets and some don't.

It's all going to add up $$ real quick. Even the nitrous fuel enrichment system at it's most basic for is gonig to cost maybe $500 for lines and pump and tank and regulator. Then you'll want a nice ignition-nitrous controller like the Accell that will provide window switches and rev limits and timing retard.


karl
 
G

·
Discussion Starter · #8 ·
Sorry for going off subject. I was wondering what nitrous systems you are running. I am fixing to go this same way? Thanks and sorry for the change in subject.
 
G

·
Discussion Starter · #9 ·
Tom even before that weren't you running a Racetronix relay kit?
Oops, forgot about that. Yes, I switched over to that harness even before I went to the N20.

95'dggm$: At a minimum I'd get the harness, plus the 255 high pressure pump. I believe there is only one 255 available for us from Walbro now, but just incase, be sure to get the high pressure unit as I feel that it would work better for N20 since it also offers some extra volume with it too.

If Karl isn't using his pump voltage booster, maybe you can buy it from him.

The 255 lhp pump will increase from 244lph @ 40psi with 13 volts to 322lph @ 40psi with 17 volts. Just by increasing the voltage from 13 to 17 volts you pick up 88 lph of fuel delivery.

Check out these articles:
http://www.kennebell.net/media/articles/FUELFLOWFORENSICS.pdf

http://www.kennebell.net/media/articles/FUELPUMP.pdf
 
G

·
Discussion Starter · #10 ·
I was wondering what nitrous systems you are running. I am fixing to go this same way? Thanks and sorry for the change in subject.

Just purchased the Nitrous Express 20109-15 MAF kit. I have a non-standard LT1 intake and like the ease of this kit. On a single stage you can spray 250 HP. With a dual stage, 250 x 2?, but I don't plan on this. I plan Stage 1 with a light hit, and Stage 2 with a 150 shot. That should help with traction.
Direct port systems rule, but it's not as easy to do and rejetting sucks...
I do think a dedicated N2O fuel system is optimal for a street driven car. I can pump up the octane and not go broke, plus I know what the exact octane is. (ie. race fuel not mixed with crappy 93 octane street gas. Octane = ?)
I'm still planning-out the N2O control stuff however. This is the hard part.
 
G

·
Discussion Starter · #11 ·
I'm running the NX wet kit with the Shark nozzle. Last year I was running a 150 shot, and picked up 1-1.2 seconds with it. To control the happy gas, I use a MSD Digital 6 ignition box, and a MSD Digital window switch. The two work wonderfully together.
 
G

·
Discussion Starter · #12 ·
On the Walbro 255...I'm searching around and find 2 part #'s w/install kits....one is listed as high pressure...I would assume this is the upgraded pump, as mentioned above, to use with nitrous?
and I also only see 94-02 F-body pumps...would the install kit be the same #GSS340M?

255 kit
 
G

·
Discussion Starter · #13 ·
OK....so I looked at the Kenne Bell site that was linked...but my computer is to weak to run PDF software...so whats the skinny on getting 17 volts to the pump...bigger wires,alternate power supply?
 
G

·
Discussion Starter · #16 ·
OK...so to keep the thread going.....if you go with a seperate fuel system under the hood,along the lines of a 1 gallon tank....how much of a pump is necessary to just supply the additional race fuel to the system in addition to the stock pump that already runs the engine under normal operation.
Could you go with an inline off the shelf from the local parts store...the last one I bought was around $40?
How many gph is needed for the enrichment system alone?
 
G

·
Discussion Starter · #17 ·
G

·
Discussion Starter · #18 ·
You need to decide if you want to run EFI pressure or Carb pressure.
If you run EFI, just the MSD Inline Pump, an Aeromotive Regulator and whatever size line you decide.
If Carb get either the Holley Blue or Black pump and regulator. I would not run anything smaller than 6-AN for the Carb settings.
I have 6-AN for EFI settings, that is enough fuel for anything I am going to throw at it.
 
G

·
Discussion Starter · #19 ·
how much of a pump is necessary to just supply the additional race fuel to the system?
-----------------------------
I'd say figure out the HP of the shot and go from there? Would it be easy to say, for a 150shot, you'd need a pump for 150 HP engine? I think any small EFI pump would work, as long as the regulator can bleed-off the extra fuel....
So for a 250shot, I'd need a stock fuel pump.--
OR am I missing something?
 
1 - 20 of 26 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top