gst fuel pump on 420aturbo

[dsmking101]

hey guys can a gst fuel pump work on a 420a turbo will it work well and be safe to run boost with the 420a...thanks guys

 

[99BoostedRS]

They have diff fuel pumps. If i were you I'd just get a walbro 190lph fuel pump for your car.(That fuel pump is good for about 450hp or so I've heard.)Or maybe you can do some rewiring with the connector of the GS-T pump maybe that would work but I'm not too sure.

 

[Locke]

Neither a GS-T/X pump nor a Walbro 190 will be suitable for a 12:1 FMU. If you were using MegaSquirt, then these would be options.

 

[dsmking101]

then what is suitable with out MS ? what pump should i use?

 

[Locke]

Walbro 255HP

 

[dsmking101]

thanks guys for the help i figured it out the 255pump works just runs a lil rich but it works dident work before because one of the fuel hoses were lose so i was losing pressure... causing my car to stutter and eventualy die fixed the problem so i have the 255 back in there and it works fine thanks for the help guys thanks locke

 

[Carter_95RS]

Sorry to thread jack, but i am seeming to have the same problem. I've been turbo for roughly 1k now, but the only problem is is that i'm on my stock pump, so i'm more than likely running lean in boost...so i try to stay out. I have a 255hp pump, but whenever i put it in the car, it runs like crap! it will idle for roughly 20 seconds then bog out and die. With the stock pump, i have no problems...i'm stumped for the solution...I want to switch the pump to the walbro so i dont have to worry about being lean under boost conditions. Any help is appreciated.
-Jared

 

[dsmking101]

put the 255 back in and make sure eveything is tight hose's ,clamps,ect... then try it out if you still run into the same problem your fpr maybe be messed up..and its not functioning properly with the 255..make sure eveything is tight and secured so you wont leak pressure..

 

[dsmking101]

carter 95rs ....i thought it would be a lose hose or a leak of pressure but im having the same problem all over again it would idle for about 30secounds then shutt off and when i drive itll shutt off also i did a blt check everything is ok with my stock pump it ran fine and never shutt off when i tryed it last week but now that i put my 255 in there its doing the same thing as befor.....maybe i need an afther market fpr idk any suggestions....

 

[ramsack]

If you were using MegaSquirt, then these would be options.

If one was using a megasquirt, wouldn't a 1:1 regulator be more feasible to use since it can actually be tuned, and not relying on an fpr to try to keep a certain a/f ratio?

 

[Locke]

When using MegaSquirt, a typical 1:1 FPR is highly preferred. A rising rate regulator such as an FMU would be a nightmare to tune around.

Though in my previous post I was referring to the fuel pumps and not the regulator, you're right in that I should have been more specific.

 

[dsmking101]

so locke what do you think is the reason why this is happening? carter 95rs is having the same problem i would like to brake down ideas and figure this out so we can help him also.. are we missing something to sapport the 255 or...?? thanks locke

 

[Locke]

Ideally, logging fuel pressure with other data during a run would help, but this would require a fuel pressure sensor and some sort of logger capable of logging auxiliary user inputs.

What is your fuel pressure at idle?
What is your fuel pressure when you free rev the engine a bit, to perhaps 3krpm?
What is your fuel pressure at cruising speeds?

 

[HadesOmega]

Yeah you need to check your fuel pressure out. I'm running an airtex inline fuel pump that came with my Star Turbo kit and man it sure can pump fuel. But you shouldn't have problem with idling or running too rich because the fuel pressure regulator is the one regulating the fuel. Now there may be something wrong with your fuel pressure regulator. I know my pump works because when I turn it off and just run on the stock pump once I hit boost my AF ratio goes from GREEN to RED. So you definately need a powerful pump.

Also if your not going with some special engine management like these guys are suggesting DEFINATELY upgrade to a SFMU. With an FMU you can tune your rising rate like the FMU but you can also adjust your static pressure so you can run bigger injectors and still have them idle like stock. Right now my RS is running 22psi FP and 10psi of boost at I think 10:1 rise (I think I forget). Then you can use something like a SAFC to fine tune your AF ratio. It works pretty well but there's a limit to the size of injectors you can use and still be able to idle with such a low FP.

 

[rstare]

Also if your not going with some special engine management like these guys are suggesting DEFINATELY upgrade to a SFMU. With an FMU you can tune your rising rate like the FMU but you can also adjust your static pressure so you can run bigger injectors and still have them idle like stock. Right now my RS is running 22psi FP and 10psi of boost at I think 10:1 rise (I think I forget). Then you can use something like a SAFC to fine tune your AF ratio. It works pretty well but there's a limit to the size of injectors you can use and still be able to idle with such a low FP.

You can't tune at all with an FMU, but I think that might have been a typo.
The rising rate that you want the SFMU to have is based on the size of your injectors, mostly.
You wouldn't want to use an SAFC to fine tune, because you can't really use it in boost. Not to add fuel at least.... That's a whole different story, though.
The point is that if you have an SFMU, you don't need a SAFC. The SFMU has a bleed valve so you can lower the rising rate to rates in-between those given by each disk. Meaning you can get a pretty decent tune with the SFMU. No need to throw an SAFC in there an complicate things further.

 

[dsmking101]

ok so i need a sfmu to replace the 12:1 fmu or just the sfmu with the 12:1 i already have to fix this whole fuel problem? just want to make sure thats what i need or do i need something else?

 

[Locke]

I'd sort out your current fueling problems before you bother with upgrading the fuel system.

Please perform the fuel pressure tests I suggested earlier.

 

[dsmking101]

ok so im going to go ahead and buy a adjustable fuel pressure regulator to sapport my 255....what afpr do you guys recomend i use and what psi should i set it on thanks

 

[Locke]

Set it to 50psi, and leave the vac source on it unhooked.

The Aeromotive AFPR is very popular.

 

[dsmking101]

ok thanks locke i serched and i couldent really find any info on how to install an afpr i herd it wasent that hard but if you can i will like a lil more detail on the install thanks

 

[Locke]

The factory late model "returnless" fuel system has the FPR located back by the fuel tank. You will have to remove this, then just install the AFPR in the return like, going back to the tank. It'll have to tee off the supply line.

Alternatively, you can extend the return to the engine bay, and make the tee just prior to the fuel rail, or convert to an early model "conventional" fuel system which would place the AFPR after the fuel rail. (in this case, you would have to disable the FPR on the rail)

 

[dsmking101]

got it thanks locke im going to install it once i get it in the mail ...so would it be safer and better to leave it in the back or it wouldent make a diffrence to move the afpr to the engine bay to do this i need longer hose right?

 

[Locke]

Moving it to the front allows you to adjust it more easily, monitor it, and show it off (if you're into that). I'm personally a thrifty person that doesn't care much about showing off, so I'd just install it in the back.

 

[dsmking101]

yea i know what you mean.... thanks for the help locke i appreciate it ill let you know how it gos once i install thanks