Just installed my Walbro...

[CajunKenny]

I finally installed my Walbro after a year and a half of it sitting on my bench. I installed a new fuel filter as well.

I immediately noticed a few things.

1) Super smooth idle (was stumbling at bit prior to the Walbro & Filter)
2) A drop in fuel pressure. Went from 35 (vac off) to 32 (vac off)
3) Running a little more rich. Instead of hitting 11.0-11.3 at WOT it now hits 10.7-10.9 at WOT

Anyone else have similar results after a Walbro install?

 

[grimreaper]

yep, fuel pressure at idle has to be in the gutter to get anywhere near 11's at wot for me too. The pump has way more fuel then the sp61 needs at pump gas boost levels...

 

[jdub]

Kenny - did you remove the J-tube (or drill it out) as part of the pump install?

 

[IwantMKIII]

Don't forget the 12V mod for tuning purposes if you haven't already

 

[NTRA08]

Question: What does the j-tube do?

 

[isnms]

fail safe for fuel pressure
http://www.supramania.com/forums/showthread.php?t=34548&highlight=j+tube

 

[CajunKenny]

Kenny - did you remove the J-tube (or drill it out) as part of the pump install?

I have the areomotive AFPR kit. J-Tube gone!

Don't forget the 12V mod for tuning purposes if you haven't already

I'm not sure I want to do that yet, or at all for that matter. I've read too many conflicting threads on that subject I guess. I had planned on waiting to see if I'll want to do that after I get my Maft in and start tuning.

 

[CajunKenny]

So should I put my fuel pressure back up to 35?

 

[grimreaper]

I have the areomotive AFPR kit. J-Tube gone!



I'm not sure I want to do that yet, or at all for that matter. I've read too many conflicting threads on that subject I guess. I had planned on waiting to see if I'll want to do that after I get my Maft in and start tuning.

I never had an issue with the switch over as my turbo doesnt come online till well after 3000rpms, yours may differ...

So should I put my fuel pressure back up to 35?

uhh does the car need the fuel? wot AF ratios indicate a slight drop in PSI would put you back at an optimal 11's range.

Understand your vf's are probably in the tank now with out some adjustment on the afm screw or piggy back.

 

[IwantMKIII]

I'm not sure I want to do that yet, or at all for that matter. I've read too many conflicting threads on that subject I guess. I had planned on waiting to see if I'll want to do that after I get my Maft in and start tuning.

Conflicting Smonflicting. Most members only arguing point is longevity issues. My response is its a walbro, that's what you bought it for, to take the extra added abuse and have some extra flow. GL tunning the kinks out of the system whenever it randomly decides to switch from 9V to 12V and your AFR's get all screwy...

Besides, I'm over 10K miles on mine pushing 50-60PSI under boost and will be happy if it lasts another 10K, though it should last much more. I mean really, they're only about $100 and even at 20K miles that $.005 or .5 cents per mile.

 

[CajunKenny]

Grim: No, I'm hitting high 10's at WOT now. I'll leave it.

My Maft and 550's are next. It's going to be a little bit of time and work because I'll be changing intercoolers and intercooler pipe so I have to coordinate the time with my welder friend. He's going to provide some NICE welds!

I've only done a little research on the vf thing. I'm VERY much a noob when it comes to that so I'm a little lost there. Should I back the screw all the way out until I get the Maft in?

 

[CajunKenny]

Conflicting Smonflicting. Most members only arguing point is longevity issues. My response is its a walbro, that's what you bought it for, to take the extra added abuse and have some extra flow. GL tunning the kinks out of the system whenever it randomly decides to switch from 9V to 12V and your AFR's get all screwy...

Besides, I'm over 10K miles on mine pushing 50-60PSI under boost and will be happy if it lasts another 10K, though it should last much more. I mean really, they're only about $100 and even at 20K miles that $.005 or .5 cents per mile.

Yeah, that 9 volt drop is what I heard is the headache. I hear ya on pushing it. That's what they're made for. I just figured I'd do it later on. Plus, it'll give me more appreciation for the mod.

 

[NTRA08]

just asking. I have a afpr like kenny. I just blocked it off

 

[grimreaper]

the ONLY thing i noticed from the 12v mod is a tad higher psi at idle vac on... thats it. No tuning issues, no switching issues and no scratching my head wondering what the hell was that type of thing (before the mod). I did it to increase fuel pressure at idle since i have to drop PSI so much to get the safc with in a -15% range MAX at wot.
I guess if your turbo is coming on really early it could be an issue, however a bit lean at positive boost will help increase spool time.

 

[GC89]

however a bit lean at positive boost will help increase spool time.

and detonation which will lead to a blown head gasket or worse

 

[grimreaper]

^ if your detonating at 25-3000 rpms something is wrong. PTB i can see as things are in closed loop (think EGR delete), not at open loop though where there is more fuel being added then stoich.

 

[IwantMKIII]

the ONLY thing i noticed from the 12v mod is a tad higher psi at idle vac on... thats it. No tuning issues, no switching issues and no scratching my head wondering what the hell was that type of thing (before the mod). I did it to increase fuel pressure at idle since i have to drop PSI so much to get the safc with in a -15% range MAX at wot.
I guess if your turbo is coming on really early it could be an issue, however a bit lean at positive boost will help increase spool time.

Then you weren't looking well enough, its pretty easy to spot the switch with any AFR logging software.

Simple example. My first dyno run. I had like 5 bajillion boost leaks and AFR's were going nuts but the switch is pretty easy to spot...Keep in mind the switch is all in one place b/c every run was the same, WOT. The switch can occur anytime which is the issue. Also note, 3 lines are AFR and 3 lines are boost levels

[thumb]http://img301.imageshack.us/img301/262/cutdynolb1.png[/thumb]

 

[GC89]

^ if your detonating at 25-3000 rpms something is wrong.

Thats one of the bigest problems with the factory ecu tune. At cruise when put under just enough load to build a few lbs of boost the ecu doesnt richen up and switch to open loop. These conditions will lead to detonation, and contribute to the 7m blowing factory head gaskets so easily. This is why you tune for your AFRs to switch to wot mix at any positive pressure or 3/4 throttle ish. Im not trying to argue with you I just think its an something to keep in mind when tuning. Lean will spool much better and create substantially more power but I like to stay on the safe side, even if it costs a some power overall.

 

[grimreaper]

Im not taking offense, just making sure we understand each other , the condition you provided as an example will not be affected by the 12v mod at all. The ecu is still going to run stoich or a bit richer regardless of the fuel supply in closed loop.

 

[grimreaper]

Then you weren't looking well enough, its pretty easy to spot the switch with any AFR logging software.

Simple example. My first dyno run. I had like 5 bajillion boost leaks and AFR's were going nuts but the switch is pretty easy to spot...Keep in mind the switch is all in one place b/c every run was the same, WOT. The switch can occur anytime which is the issue. Also note, 3 lines are AFR and 3 lines are boost levels

[thumb]http://img301.imageshack.us/img301/262/cutdynolb1.png[/thumb]

i see, i guess its not an issue with mine due to when boost comes on with my setup