Worth 8 bucks?
 

http://cgi.ebay.com/ebaymotors/ws/eB...1902577&rd=1,1

is this worth the 8 bucks to add to my FMU?

with that background music on ebay, i would say no lol

its only 8 bucks, give it a try

I don't see why it won't work. You'll vortech will almost be like the BEGI unit without being able to adjust the base pressure. I'd say throw in the 12:1 disc, go to home depot racing and by the same fittings and a check valve and give it a whirl.

i use an MBC on mine unless you are running 300cc's I wouldnt ramp down the rate to much 12-1 isnt to bad. My setup essentialy delayed the ramp up until 1-2psi and then continued from there. For 8 bucks it is worth a shot but a MBC can do the same.

I thought it would work. I couldn't make it happen. Braineack tried too, and he couldn't get it to work right either.

IMO the problem is less of controlling pressure rise and more of controlling injector duty cycle.

thanx guys

can someone explane to me how this thing helps my fmu?? The fmu i have is 12:1 i was gonna change disks to 8:1.. with this bleeder valve i will be able to run my 12:1 disks, and adjust it to work with my setup??

i guess you could say im a bit unknoledeged in the FMU arena

i tried a pressure regulator to cap the amount of fuel pressure...this should work....looks to be straight off an old BEGi unit.

Drill and tap a hole in the body of the FMU/AFPR/Doodad that will take a hosebarb. Connect an MBC (ball and spring, not a bleeder) to the hosebarb and a check valve to the MBC. This will cause the AFPR to vent at a preset boost level, should stop fuel pressure from rising past a certain level. This should allow adjustment of base, rate of rise and maximum.

All theory. I was going to try it but sold my AFPR before I got around to it.

This is a good idea. I'm gonna try it.

it would be easier just to put one teed off the vacuum line...no drilling.

:dunno: Worth a shot I guess, but in my mind it won't work. I think all that will do is vent boost to atmosphere without affecting the pressure signal to the FMU. I would add a check valve between the tee and the mbc being used for the bleed.

i dont think the design of the vortech fmu will allow for drilling anyways....since the boost pressure pushes down on the diaphram. I might make myself another cheap little MBC and try it.

I thought we were talking about the BEGi FMU. The vortec SFMU has a simillar bleed to limit max pressure, like what we are discussing. Your idea is worth a shot, imo, especially before drilling.

Dunno, it's really the wrong solution to the ecu programming problem anyway.

The problem I think is that the boost pressure over runs the needle valve on the BEGI unit and fuel pressure continues to climb. Adding in the MBC as a relief valve should allow it to hit a set PSI and keep it there no matter how much boost you run or how quickly you get there. That way it shouldn't affect the rate of rise. Putting the relief valve BEFORE boost enters the AFPR will affect the rate of rise, similar to a restrictor.

I think bell should incorporate this into the design and give me a shiny new turbo kit for my idea! :)

but isn't that exactly how the BEGi fmu works....just using a bleed valve, not a MBC that pops open.

Except that it bleeds all the time, slowing the rate of rise. Putting the MBC in addition to the needle valve will pop when it hits say 10psi and will not go any higher. You'd have to use a good sized fitting. If an MBC can maintain XPSI for a wastegate it should work this way as well.

The needle valve doesn't bleed off the pressure fast enough. If it did the AFPR would never build any pressure and it wouldn't work.

Jay

magna are you running a 12:1 fmu??

Well on that regard, when the mbc "relief valve" pops open, wouldn't it just vent all the pressure in the FMU to atmosphere? Which would then drop you down to 0vac fuel pressure.