The famous stumble...fixed?

[heiche]

I got around to doing this mod and am seeing a pretty large reduction in my fuel trims, definitely worth while!

 

And no more stumble!

 

Rerouting the FPR signal hose to the BPV signal hose? Definitely! Such an easy cheap mod that really helps driveability!

[FJuan]

Rerouting the FPR signal hose to the BPV signal hose? Definitely! Such an easy cheap mod that really helps driveability!

 

Finally got around doing this a few days ago, so far it has been smooth and feels a lot better. We'll see in another week.

[hadvw]

Going great so far..

[StkmltS]

OP where did you buy the T fitting for the pressure gauge?

I've been trying to find one locally but it's evading me like the cure for cancer.

Edited May 3, 2017 by StkmltS

[GTEASER]

Look up turkeylord here on the forum, he sells them.

[TheMonaLisa]

I got a T-adaptor and fittings from NAPA

 

 

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[Slammed05]

Has anyone done this without using the quick disconnect fittings, I don't see why not just use a traditional fuel hose, and a worm clamp? Seems easier cheaper and less complicated and you can get everything locally

[m sprank]

It can be done. The quick disconnects should be available at a local auto parts store.

[Slammed05]

I'll have to take a look but kinda browsing advanced auto I didn't see that specific size disconnect

[m sprank]

Ask at the counter. They rarely have them on the floor.

[StkmltS]

I used high pressure hose and fuel injection clamps.

[zero260]

Dorman makes the Quick disconnect fittings part # 800-120

[Slammed05]

Has anyone else noticed a pretty big increase in mpg, this tank which I swapped our for this kid at about 3/4 of a tank, and spilled some gas doing it, I got about 40-50 miles per gallon than I usually do!!!

[awfulwaffle]

Here's a fun question - any of you guys that did this notice a change in the sound of the fuel system pressurizing when you first turn the key to ON after the car has cooled down from operating temps some?

[covertrussian]

Has anyone else noticed a pretty big increase in mpg, this tank which I swapped our for this kid at about 3/4 of a tank, and spilled some gas doing it, I got about 40-50 miles per gallon than I usually do!!!

 

Which part did you do? Extended fuel hose, new FPR, new FPR vacuum location? It seems unlikely for you to gain MPG unless your FPR was bad.

[Slammed05]

What do you mean what part did I do? I relocated my fpr vac line to the bpv, and replace the oem fpr with a sti one, litterally did exactly what the op did

[Slammed05]

Here's a fun question - any of you guys that did this notice a change in the sound of the fuel system pressurizing when you first turn the key to ON after the car has cooled down from operating temps some?

 

Yes, sounds like a airplane flying over head lmao

[covertrussian]

What do you mean what part did I do? I relocated my fpr vac line to the bpv, and replace the oem fpr with a sti one, litterally did exactly what the op did

 

There are multiple mods outlines in this thread, that's why I wanted to know for sure on what you did.

 

My best guess would be, your fuel pressure is no longer bouncing around with the new vacuum line (though STI FPR is probably helping with this too). Because fuel pressure is a consistent FPR your no longer over/under fueling. Also having a consistent higher fuel pressure is good for fuel economy too, due to atomization effect.

 

I personally didn't see any MPG increase, but that could be because my AVCS table is not stock. AVCS changes how much manifold pressure you would have based on overlap, which would effect the FPR.

[Slammed05]

Yea I'm not sure, but I was seeing 230/240ish to a tank, this past tank I got like 280ish at the same spot were I'd get gas, so I most definatly saw a mpg increase

[Pazuzu]

Will 5/16 hose and some fuel injection clamps work without the quick connects?

 

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[m sprank]

It can work.

[Slammed05]

Yes, that's how mine is set up, the upper hose with gt fpr you can just disconnect and reuse those lines to put the new fpr right in line

[ashwinearl]

Hi all,

Of the three approaches:

1) change the FPR vacuum source to the BOV line.

2) replace stock FPR with 04-07 STI AND 1)

3) change length of fuel lines.

 

Is there any consensus if one approach has proven better than another?

 

If extending fuel lines is there guidance I can give a mechanic on what sections and lengths?

 

Is doing just 1) without doing 2) worth it?

 

I have an Etune on there now. Is a re-tune needed after performing these types of changes?

 

Thanks

[heiche]

For my 05, your #1 and #2 each corrected a separate issue.

 

#1 smoothed out some rough patches between 2K and 3K rpm, and it drove smoother in general. Seems like it should have been this way from the factory (vac source from common intake source rather than one runner)

 

#2 helped with a tip-in bog I had. Example: if I was cruising or decelerating, and I pressed the throttle, there would be an annoying momentary hesitation, then it would go. Changing to the later regulator fixed that transitional bog.

 

#3 I didn't bother with, as the above was good enough for me, and I really didn't like the idea of having all that extra hose coiled up, seemed way too hacky.

[covertrussian]

1. Yes changing the FPR to BOV line is worth it even on it's own, having a more constant vacuum source is important. It's also stupid easy and takes no time to do.

 

2. This is another one that's really easy to do, and cleans up some space (plus weight reduction!)

 

3. I personally don't think this one does anything, because there is already 5 feet of fuel lines from tank to engine bay. What this might do is help the fuel pre-warm up in the hot engine bay, though I'm not sure that will do anything either. So I personally would rate this mod as a placebo and skip it.

Edited July 21, 2017 by covertrussian