FMU sizing/ fuel pressure

[NCState98]

I've had the powerdyne kit installed for awhile and just had to swap some cracking fuel lines on my FMU. In the process I pulled it apart. Anybody had the experience to estimate what ratio I should be boosting my fuel pressure by from the picture?

I put the fuel system back to stock for a day until I could get the right lines and fittings for the FMU and realized that I don't think my FMU is boosting the fuel pressure much over the stock regulator. Fuel pressure is around 44psi at idle, 50 at 0 boost/vacuum, and as seen just under 60 psi at 7lbs. Until I get on the dyno, I fear that I'm running pretty lean. Surely my FMU is set up higher than 1:1. Any ideas?

http://img204.imageshack.us/img204/5...da060058ag.jpg
http://img133.imageshack.us/img133/7131/xenon0143hp.jpg

[ssms5411]

To me it doesn't look like the fmu is working at all, the powerdyne kit comes with a 6:1 fmu ratio and you would be at around 86 psi at wot. I have a walbro 255 installed with no fmu and 36lb injectors and at idle I run 48 psi and at wot I'm at 60 psi. I wouldn't run your car into boost until you get your fuel problem fixed.

[NCState98]

Oops, I take that back. I'd always suspected that my fuel pressure with FMU was a little low, so this was a test run while I had the lines under the hood back to stock. I have added the inline fuel pump and have 24lb LT1 injectors. In an older video with FMU I'm pushing 67psi at 7-7.5 lbs boost. Still might seem like its not up there where it should be, but I was wondering if this is a 1 or 2:1 disc in the FMU or something?

Yes, I'm hitting the dyno too but wanted to install my meth injection first so I can dial it all in together. Too busy with school right now and wanted to focus on cleaning the car up for show season.

Did you go with a progressive meth kit, or more simple single stage kit? I think I read that you're mixing your own methanol mixture. Have you found a good source of washer fluid with high methanol content? I've been glancing around and can't find a specific mixture listed on any bottles.

[Mighty Thor]

When my fuel pump was new my idle was around 42 and boost at 7psi was around 80.

Now I have 39-40 at idle and 60-70 at boost, rarely do I see 80 now. I asked Muscle Performance (they mostly do SC for Mustangs) if this is right. He said it's pretty normal for a 6:1 FMU and Walbro 255 pump.

[ssms5411]

Sounds like a 1:1 fmu, I got the single stage from coolingmist. I think I will be getting their controller here pretty soon. I tried alcohol and water but didn't get very good results. So I found some premixed methanol and water from Snow Performance called Boost Juice. Works like a champ. I got 4 gallons of it for 45.00 shipped or around there. With 50/50 water and alcohol I was running lean for some reason on the top end. Could of been the mixture, I don't know. But with the boost juice I stay within my A/F limits around 11.5. I really haven't gone too rich with the Boost Juice maybe 11.1 at most. I'm also spraying right after the supercharger about 18 inches before the maf.

[NCState98]

Same kit I got, and I was also planning on mounting the injector right after the blower. Did you put some sort of rubber washer between the injector and piping? It doesn't look to me like the injector will tighten down into the holder enough to fit snugly through the thin walled blower pipe.

i do have the other discs from when the guy rebuilt the FMU at home, just don't think they're labeled very well as to the size. I'll examine those when I head home again and check into my fuel pressure. Atleast it looks like the FMU is working, judging by my test runs.

[ssms5411]

I put some washers in to close the gap then used some pertinex, or rubber gasket maker around the hole to fill it in and tightened down the housing. Worked very good. Also I found out instead of using the M3 nozzle, to use a M1. The M3 and M2 were causing the car to bog after the water/methanol injection was on for so long, especially in 3rd and 4th gear.

[ssms5411]

Also if you get the controller you won't have to worry about different nozzles. From what I read on there website from coolingmist you can program the controller for the amount of water coming in, which is very nice. That will be on my list for this summer.

[NCState98]

Sounds good, I'll look into which nozzle they sent me. At the time, I told them I have a V6 camaro around 250 rwhp. NOt sure which they sent me. ARe they marked?

[ssms5411]

It will probably be a M3, they will have a M and a # beside it. Higher the # the higher the flow of water. I set my boost switch at around 8-9 psi, with the M1 nozzle. Coolingmist told me to set it 1 to 2 psi below my max boost.

[NCState98]

Wow, I'd expect that your intake temps would still need to be cooled at 4-5 psi. Thats where I'll probably set mine, as I max around 7-8. Also, did you tune much for the meth? I'm hoping that if we pull a bit of fuel at WOT, it'll keep the car from bogging. We'll see... I might have to splurge on the progressive controller.