Newbie Fuel Question

[nek]

Shame on me, anyways. Its about time for me to start modding my fuel system( did things a little backwards). Money is an issue but Im also the type of person that doesnt like buying things twice. My first question is, what is the current weakest link in our fuel system? I have boost creep and I was wondering if replacing either injectors or the fuel pump has a possibility to fix it.

From there its more opinion on upgrades.Basically comes down to $200-300 or $600-700
I could just simply go with 190 and 560s to fix my creep problems.
Or I could go with 255, afpr, and something like 1150 which has e85 capabilities and can still be tuned with link.
Eitherway, Im also gonna have to get a wb02.
Let me know what you guys think.

Alright, I did some more research and found that the stock injectors can outflow the fuel pump.

The injectors out flow the pump. The pump is said to only be good up to 15psi on stock set up. The stock injectors have been known to go past 20 on a evo316g with some other tricks or mods. You can put as big as injectors as you want on any fuel pump as long as you want but injectors wont help you when your exceeding the fuel pumps max output.

So I think Im gonna start with a 255 w/ some afpr...
http://www.extremepsi.com/store/customer/product.php?productid=21515&cat=257&page=1&veh=2G DSM

http://www.extremepsi.com/store/customer/product.php?productid=21505&cat=257&page=1&veh=2G DSM

http://www.streettunedmotorsports.com/parts/stm_dsm_fpr_fuel_return_kit.htm

Ill go with injectors later. Opinions?

 

[tsi1991awd]

Fuel pump and injectors have nothing to do with boost creep. That is going to be an issue with your wastegate / turbo.

What are your goals and plans for the car? If you want to "buy once, buy right", go with the Walbro 255hp pump...you WILL need an AFPR with it though. bigger injectors will need to be tuned. You can't run bigger injectors without at least an SAFC.

The injectors don't "outflow" the fuel pump...not sure where you're getting that from.

 

[nek]

First off, I know how creep is caused, your right wastegate/turbo issue. Im talking about how Im going to fix it so I dont hit fuel cut(sorry should have said that).
I do enjoy buying once as I stated, I dont ever like thinking ( I shoulda went with ....)
I already have ecmlink with gm maf for tuning.(still need wb02)
My injector statement (correct me if Im wrong) states that the injectors can handle a bigger pump but pump cant handle bigger injectors.. Basically upgrading injectors and not pump, wont result in more fuel but upgrading pump without upgrading injectors will result in more fuel capabilities.

 

[onlyhonestone]

i kind of have the same issue, i hit fuel cut at 18psi, with stock injectors and stock pump, will i need to tune after putting on a 255 pump?

 

[white92talontsi]

i kind of have the same issue, i hit fuel cut at 18psi, with stock injectors and stock pump, will i need to tune after putting on a 255 pump?

You can change the pump and the injectors all you want but you will still have fuel cut. You are getting fuel cut because the mass air meter is seeing too much flow.

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[nek]

You can change the pump and the injectors all you want but you will still have fuel cut. You are getting fuel cut because the mass air meter is seeing too much flow.

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sigh. and its helpful to post how you fix this. basically you need to fake the maf into thinking less air is entering the system and tell the ecu to put more fuel into those lower fuel to keep an even ratio... or something like that.. right?
How do you do it with ecm link or other tuning software. explain please.

 

[DSMunknown]

I suggest finding and using used parts (in good condition of course).


Evo 9 fuel pump (don't forget to rewire)
DSMLink V3 Lite
At least 850cc injectors
AFPR

 

[brownfinger]

sigh. and its helpful to post how you fix this. basically you need to fake the maf into thinking less air is entering the system and tell the ecu to put more fuel into those lower fuel to keep an even ratio... or something like that.. right?
How do you do it with ecm link or other tuning software. explain please.

Generally, you "fool" the ECU using the SAFC. I like stock, so I don't know how to do it with the MAF-T. With the SAFC, you get injectors that are way too big, so you dial back the MAF readings to match, thus, fuel cut is never reached.

Hope that helps, it's about all I know.

 

[tsi1991awd]

Please tell me why you would want to "cure" boost creep by adding in fuel. This is no way to fix your problem....you will still have boost creep. Fix that problem before you go and mess with your fuel.

The fuel pump controls how much fuel will flow through your rail. Getting a bigger pump will push more fuel through the system, but you will need an AFPR because a large pump will overrun your stock FPR and cause you to run pig rich.

The injectors will flow a bit more than 450cc's (assuming they are stock) if you bump the fuel pressure a little. If you plan on getting injectors, dont go over 750's or else you cant tune those with a MAFT and SAFC, you will need a chip or Link.

Fuel cut is there to prevent you from roasting your motor. Cure your creep, then tackle fuel. The way you cure creep is port your wastegate passage in the turbine housing, port the _2 housing, hell maybe even get an O2 dump.

 

[nek]

Alright, now Im more confused then when I started. Why should I need to fix the creep if my fuel system can handle the psi the system creeps to. If I creep to 21 psi, whats the problem. My fuel mods will (eventually once upgraded) be able to take it so there is no point on curing it, or thats what I thought.
And why do people keep saying dont do this unless you have link... I do have link, its in my profile...
Does creep always add x amount of creep? Or is it a set level... If my system is set to 15 psi and I creep to 20. Then I set my system to 20 psi, will I creep to 25 or stay at 20? I thought some people ignore porting because they end up not being able to hold higher boost levels.. Is there miss information going on here or what...?

 

[tsi1991awd]

If you creep, you are most likely always going to creep bro. Adding a MBC and setting the boost higher only alters the pressure signal to the wastegate itself until the ball/spring care pushed in enough to flow to the wastegate. Once full pressure is getting to the wastegate, its going to be the same....youre going to creep.

If you dont give a shit, then just slap some big ass injectors in along with a 255hp....good luck with that though.

 

[nek]

Yeah I just bought a O2 dump, It has a good rep to cure creep plus there are mixed reviews but many say it sounds bad ass and others say it gets old. I love loud so I figured Id give it a shot. I didnt mean to sound like I was shutting you down or anything but Ive seen posts of people complaining that they cant hold higher pressures because of bigger flapper mods. And I also was under the impression that if I upgraded my fuel system, creep wouldnt be an issue.
Im also gonna go out and buy an aeromotive afpr and 255. Im not gonna get injectors until I know my goals 100%. Probably gonna go with some big 1150's bigger.
On a side note, is it true that you dont hit fuel cut once you use ecmlink? Does it automatically get rid of it?

 

[2gawdtsi]

no you have to adjust it yourself.

 

[jdub1992]

boost creep as stated before is a turbo issue. plain and simple. The issue with power is many times the fuel. running e-85 is useful for more power and is easy easy for our cars. It is simple.

get a walboro 255 they are not expensive and are just awesome!
also go with a 750 cc injector set
you will also need something like an SAFC to lie to the ECU

it takes about 25% more fuel to run when using e85 so you need bigger injectors than the stock 450 ccs and you need a bigger pump which is not required by recommended. the computer without a SAFC will also run the car crappy because it needs to know to add more fuel. I can send a SAFC hookup chart if needed. its about a 1day job really.