DisgustipatedM3

iTrader: (2)

So on a modded Wally 255, 500 whp dynojet is a dangerous level to be at in terms of fuel pressure, flow, and AFR? Hmm...

tscompusa

iTrader: (31)

i just finished another car on e85 with a modded walbro 255 and it hit around 530. i did not have to do anything weird with this car in the fuel map.

https://www.evolutionm.net/forums/ev...93oct-e85.html



the afr was going leaner at high RPM, but i also have the boost set to increase as well.

now im about to retune the car in the first post of this thread so we will see what happens.

this car however, is on 1450cc fic's.

--------------------------------

Update on this: The car had 2 semi large vacuum leaks, and as soon as we fixed them, the car shot lean again at high RPM:



So i richened the fuel map, and got the afr down to low 12's again which are acceptable, but i think another vac line popped off
the car again making it go richer. I guess its safe to say the modded walbro 255 shouldn't be taken past 500whp on e85 with stock rail, lines, fpr.

tscompusa

iTrader: (31)

ok he did the pull!

Here is the car in the first post of this thread after the walbro was modified. we did not change the fuel sock, so this is a direct back to back after modding the pump. its still lean uptop, but it has helped a lot. now to see if i can make it go any richer uptop.

detroit pistins

iTrader: (102)

Amazing what a simple mod could do. anyone has a link to this fp mod mentioned above?

evolved0414

iTrader: (5)

https://www.evolutionm.net/forums/sh...9&postcount=20

Here's the link that Tom gave me

detroit pistins

iTrader: (102)

^ thank you!

apagan01

iTrader: (299)

My concern would be how has the mean time between failure afected by the modification, as the pump will in theory be running harder. We all know walbros are heavy but !

dtrackstar

iTrader: (20)

What capabilities does a modded 255 and a rewire have on e85

evolution1rs

These guys have done some testing and comparisons on the Walbro 416
http://www.radiumauto.com/blog-page....l-Pump-Test-73

Draws a lot of current but a good little pump. Very quiet!

I'm running one at 550whp on E85 and no issues so far

tscompusa

iTrader: (31)

thanks for sharing, but there's no way a walbro 255 is as loud as a bosch 044 from my experience. those pumps scream. i cant even hear my pump at idle with the seats out the back and the lid off. that tells me they must of used a used walbro 255 for that test. i have had them get very loud, but it was due to old age or clogged filters. I use gss340's though, they have bigger openings at the filter then gss342's. unless the bosch 044 doesnt scream until it sees alot of pressure maybe?

i still would rather see it tested at kinsler fuel labs where it is 100% accurate information produced by a flow bench test machine designed specifically for testing flow rate of the pump.

I don't know the answer in bold, but i hope not. wouldn't that only be effected if you drilled the siphon hole bigger? the actual size of the return line will effect how that operates?

I'll admit, i don't know how that part of the fuel system works. I never looked into it. you're referring to the "T" right?

in regards to the dw300, the modded walbro beats it pretty severely.

i agree, you cant beat the dual walbro setups. when the switch fails though, one pump has just enough fuel to blow the engine, which is not a good thing. its a rare thing, but it has happened to me. that doesn't stop me from not reusing it again though. it worked for me for 4yrs+ flawless (30k total miles), and almost 80% cars i tune with big setups use it and you rarely ever hear about them failing.

The lesson i learned is, if you start experiencing symptoms, test everything before proceeding to trying to go out and floor the car again over and over. there are fail safes you can implement also to remove boost when this type of thing happens (lean afr's), so there should be nothing to worry about.

550whp seems super conservative. i just did 520 with 1450cc inj, stock lines, with a modded walbro 255. not hard wired. granted i had to richen the top end of the map drastically to get the afr into really low 12's from 13's, but im pretty sure STM has done 580-600 with one with their install kits on their mustang dyno with stock lines as well on the walbro 400-416. add 13% for dynojet numbers, and you see that's drastic vs your results you just said.

600whp on a mustang dyno is a lot of power assuming the dyno operator has it setup right and uses the 15.1 value for power at 50 or whatever it is. I wouldnt even attempt that power level on the aeromotive, id go to something like a double pumper or equiv.

dangerous? no, but it is pretty much done for at 520whp. i would not recommend it past 500 based on my testing with multiple other cars this past week on e85. 93octane is another story though. you will be more then fine on race gas and 93octane. e85 if you want more then 500whp, i would switch to a 416lph walbro or a double pumper setup.

surprisingly modding the pump doesnt seem to hurt its lifespan. people have been modding the walbro 255 since the year it was introduced and you really dont see them failing due to the modification. the check valve exists only incase your fuel system clogs and the check valve would open relieving the pressure from the pump, if for some freak reason the pump could explode (very unlikely), but walbro has to protect their name and product if something like that were to occur.

The check valve is merely just a ball and a spring, so you can push it down just enough to put more tension on the ball & spring setup making it stiffer, which in turn makes it not open until a later PSI is reached. so technically you can fine tune the ball & spring to hold higher PSI and still benefit from the modification without fully disabling the safety feature.

non rewired it is completely out of fuel by 520whp. i wouldnt go past 500whp on the modded 255 on e85.

injectors play a roll also. this car you can see is borderline safe (12.5 afr at high rpm), and he only touched 480whp. he has 1050cc fic injectors though.

my other customer reached 520whp with 1450cc inj, and we have gotten the afr down to a 12.1ish range. that car is completely out of fuel pump though.

so if you want more then 500whp on e85, i hate to say it, but the modded walbro 255 is not your answer.

dtrackstar

iTrader: (20)

How much do you think the rewire would help?

Thanks for taking the time to answer !

mrfred

iTrader: (50)

Having to massively richen the fuel map says it all - I guarantee that pressure across the injectors is dropping from the target value of 43.5 psi down to 30 psi or likely less. My guess is that for 520 whp with the stock supply line, its probably down to 20 psi. Pressure across the injectors is supposed to stay at 43.5 psi at all times. (For those who may be thinking that I'm talking about rail pressure, I'm not. I'm talking about the difference in pressure between where the fuel goes into the injector [fuel rail pressure] and where it comes out [intake manifold where boost lives].) If you look at the link I put in an earlier post, you'll see that when I was testing the various 255-ish pumps, I was logging as low as 32 psi across the injectors. You're only able to get away with running below 43.5 psi on that customer's car because of the 1450 cc/min injectors. I bet IDCs were up near 100% when they should be closer to 75%.

For the Walbro 416, when I say 550 whp, this is a number I feel confident can be attained without comprimising pressure across the injectors. If people are willing to let pressure across the injectors fall below where its supposed to be and run 2000 cc/min injectors to try to get around the deficiency in pump capacity, I would agree that 600 whp is potentially attainable.

That 520 whp car is relying entirely on the pump not loosing any capacity at all to keep the correct AFRs at the top end of the rpm range, and pressure across the injectors is for sure way below where its supposed to be, so I would tend to call that dangerous.

Are you saying that the guy with the 520 whp tune on the Walbro 255 needs to go install a bigger pump?

tscompusa

iTrader: (31)

so are you saying that even though our cars only have one fuel rail, and there's only one feed line to that rail, that there can be not enough pressure to the one rail so the injectors may not equally have the same spray pattern / pressure coming out of all 4 due to the lack of pressure to the rail due to not having a strong enough fuel pump?

if that's the case i will detune that car until i can use the fuel map normal again on it.

but id like to read up documentation on it that states that's whats happening 100% before i do it. i just want to read where you read about it. if that is true, then 480whp would be the absolute limit of the modded walbro 255 as far as safety goes on e85.

tscompusa

iTrader: (31)

i think i see what you're saying now. if the pumps not flowing enough, then the injectors will not get the full 43.5psi and instead they may get only 20 or 30psi in total.

that would mean that instead of having around 20psi of fail safe pressure to work with to the injectors incase your pressure drops, you basically have next to none?

if that's correct then ya, that's not safe and not something that im gonna leave on the customers car.

ctfpevoVIII

iTrader: (4)

Tom what WHP on 93 oct plus meth would a un-modded 255 be able to support. The only reason I ask is I'm swapping out my HKS 272's for GSC S3's and don't want to run out of fuel or have it un safe? Sorry for going off topic.