sweet99ss

iTrader: (41)

So looking to see what kind of power you guys have made with a walbro 255 pump. I have granatelli 255 pump and i will be running a 408 with nitrous and looking to see how much power I can throw at it before it will run out of fuel. I'd like to see 600rwhp.
So everybody post up the max rwhp you have made with a walbro 255 pump! Please include if you are FI or NA. I'll also make a poll for this.

KCS

iTrader: (20)

I can't help but think this belongs in the Fueling and Injection section. I'll go ahead and move it for ya.

CarlostheBarbarian

Not sure of limits but Im at 620rwhp on a HCI ls6 w/ a 150 shot. Walbro 255 w/ a racetronix voltage harness. A/F steady around 11.4.

Held up for about 25 pulls at 1/2 mile events so far

sweet99ss

iTrader: (41)

Awesome to hear that! Gives me hope I can spray this motor with a decent amount of n20!

conan

iTrader: (5)

I was loosing fuel pressure with my single Walbro and hot wire around the 550 hp range, @ 8#'s of boost. It would fall from 62 psi to high 40's once I crossed 5,000 rpm. I think boost is a little more demanding on pumps VS NO2.

00Z-28Maro

iTrader: (1)

I hit 550 on 9 psi through a 9" and th-400 with ~ 11.8 afr. When we opened the cutout the car made 573 but jumped up to 12.2 afr. I'm running a single 255 now with stock lines and rails but 60lb injectors.

DietCoke

iTrader: (18)

No, your supercharger requires fuel to drive it, that doesn't show in your power numbers because of the parasitic loss. Subtract 10% for supercharged power, always, for the power(and thus, fuel) required to drive the super. Turbo/nitrous dont have the same issue.

conan

iTrader: (5)

Thats a good point, it is crazy how much power some of the bigger blower need just to spin them.

sweet99ss

iTrader: (41)

Are you supercharged as well? 573rwhp is pretty stout. Is that the power level you were at when you ran times in sig?

I wonder how much elevation has to do with it as well. Everything has to work harder to over come that d/a. Seems your pretty high up there.

conan

iTrader: (5)

I don't think elevation has anything to do with the fuel pump. The blower produces X amount of CFM and the fueling is tuned to keep up with the engines demand as the CFM rises. If anything I would say the pump has an easier time on my car because I can't produce the same PSI of boost at the 6,500 FT as a blower spinning the same speed at sea level can. The roads I drive are in the 6,000-7,500 ft elevation range btw.

sweet99ss

iTrader: (41)

That makes sense. Basically higher elevation just makes the engine get less air so that would just mean less fuel in the end...

Also everybody keep posting what numbers you have made on a walbro 255 pump. Or you can post your 1/4 times and trap speeds with a single walbro 255 if you don't have dyno #'s

blk00ss

iTrader: (66)

I made 505 on motor and sprayed 150. Made 649.9. But only trapped 105ishthe 1/8th. But that was seriously full weight. Like zr1's, AC, everything. Except spare lol. That was with a single racetronix and Hotwire kit. CIRCA 2007.

sweet99ss

iTrader: (41)

Nice. I might start with a 75 shot just to make sure it can keep up. Good to see some people making good power on these pumps though.

Rise of the Phoenix

iTrader: (27)

The Walbro 255 pump is a direct replacement, correct? No modifications needed? I understand the 340LPH pump is not a direct replacement.

Nitroused383

iTrader: (10)

I've made 720 rwhp with a single walbro 255 and flowing a ton of straight methanol. Losing pressure fast that was on 11 psi. Anything over that leans out bad, not recommended.

conan

iTrader: (5)

Correct, the 255 is a direct replacement for the OEM pump in the sending unit assembly. Not sure about the 340 pump, never worked with one.

Racetronix

iTrader: (2)

Incorrect. A generic pump is NOT a direct replacement for the factory pump since none of them support the jet pump in the module.

This is why the Racetronix FPA-001B is the only true direct-replacement for the factory pump in the ORIGINAL factory module.

sweet99ss

iTrader: (41)

Nice! I wonder how much the methanol helped yout out? I might try to hit 600rwhp and go from there.

conan

iTrader: (5)

So then is it safe to say the 255 pump I swapped out for the OEM unit was a Racetronix pump. This pump I used fit right in the OEM sending unit plug and play.


Sorry its been a few years since I was on a single pump, I thought all 255's were the same.

JakeFusion

iTrader: (7)

If you are maxing out a Walbro 255... time to step up to a Squash twin kit with Deatschwerks DW200s. That'll support 800+rwhp.