I will be dropping my new built motor in shortly. Before swapping to the MS fuel system, I plan to simply swap the engines and leave the fuel system until I gather the parts needed from Slick and whatnot.

With that said, I am currently running the SFMU with the dark spring and large disk along with 310cc injectors. Currently my fuel pressure at 5psi of boost is 55psi. My question is, do I need to make any changes to the SFMU as far as disk, spring, or fuel pressure goes if I raise the boost to 10psi. Won't the SFMU's (rising rate) simply compensate from the vacuum signal and raise fiel pressure accordingly?

Let me know if Im on the right track - thanks.
(Yes I searched, there are a shit ton of fuel pressure and SFMU threads)

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s

If the AFR is already on track with the current rising rate at your current boost pressure, it should be able to work up to 10 PSI. Give it a try... Bring it to WOT in like 4th gear or something starting from 2000 RPM's so it slowly spools, watching the mixture. If it goes lean, then you will have to do something to the FPR.

2016 WRX STi Limited (current)
2001 A4 1.8tqms (donated)
1991 GVR4 #1933 (sold)
old.dsmregistry.com/detail.php?carid=218 (dismantled)

what was your outcome Ryan? Reason why I ask is because I am planning a bottom end rebuild here pretty soon, but just bought a slighted used s16g to replace my old s16g. Come to find out the person that sold me it...didn't tell me it had a 10psi wastgate. Long story short what disk/spring did you end up going with to run this. I have the 310cc/SFMU/walbro 255 and was going to run it rich on purpose to try and prolong the rebuild as long as I could. I have searched as well and this post is the closest thing I have found to what I am looking for.

Anyone let me know...please if anyone is running 10psi on stock internals with this fuel setup....lemme know...thanks!

--------------------


- 05 Subaru STi
- 97 eclipse gs (289whp w/ 276tq)

You might want to PM Matt (xtremers). I know that he ran up to 12 psi on 310s with the sfmu, although I know that he says at that hi boost level, the injectors were maxed out.

New Car:
2004 350z base, Nismo CAI, pioneer avic-n1 (dvd, cd, navi)



Old Car:
1998 GS with hrc stage 2, HID 6000k conversion kit, AEM UEGO wideband, sfmu, ml, prokits, Greddy warning gauges: egt, boost gauge, and oil pressure, apexi tt, haydans tranny cooler, costum dp, groundwires, dynotune fp gauge. gst muff, turbo spoiler
Boostin since Aug 03.

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!

I run an SFMU and an SAFC with the 310's. The SFMU is running the 12:1 disk and the dark spring, along with the bleeder vlave closed. I also run the walbro255. The 310's technically max out at 14.5 psi, but I play it "safe" and run about 13psi right now each day. Most people with these injectors run 22psi or so at idle, but I run about 30psi and lean the SAFC lo-throttle setting down to -20%. Ive datalogged it and the STFT is just fine. My car doesn't like idleing with insanely low fuel pressures. I think my fuel pressure at 13psi is about 90psi...maye even 95. But I really tune off of my digital A/F gauge and my EGT's. Digital A/F resides at about .95V - .97V...somewhere around there give or take what gear Im in...but a tad rich regardless. The EGT's dont go over 1500, 1450 usually....

The only issue Im having now is a small coolant leak I havnt had time to pin point and my vacuum is a tad low at only 14in/hg instead of 18ish....but it runs like a champ fully built at 13psi with the underdrive pully and 60mm TB...

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s

I am just seeing how long I can get away with running 10psi on stock internals by running it a bit rich until I get it rebuilt. See I was running 7psi on my old s16g, but since I bought a slightly used one the wg came preset to 10psi and the wg's are not exhangeable. So I was trying to get away with 10psi for as long as I could or until I get everything gathered for my rebuild. Anyone running 10psi on stockies?

When you did your rebuild...what all did you upgrade and/or replace?

--------------------


- 05 Subaru STi
- 97 eclipse gs (289whp w/ 276tq)

1996 Black Eclipse GS
STAR Stage 2 Turbo With custom equal length manifold and full 3 inch turbo back exhaust
8psi- 9.61- 1/8th mile
14.4- 1/4 mile
MS Powered

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s

did you do any head work? Or is your head completely stock? Did you replace any belts while you had it out?

I am ordering a built block now so if it blows then it blows!

I am going to try and run it a bit rich for the time being to try and preserve it on 10psi as long as I can!

--------------------


- 05 Subaru STi
- 97 eclipse gs (289whp w/ 276tq)

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s

Originally posted by Matt_95tgs
Damnit... you need to kick your friend in the nuts. I loved that car. Oh and BTW, I built that custom clutch in your car a long time ago

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- 05 Subaru STi
- 97 eclipse gs (289whp w/ 276tq)

He was driving early in the morning about 8am. He was on a road that was a broad right turn... it was nealy straight...but still bent right a tad. He said that he was going about 45 and wasn't doing anything crazy...and a girl in a lancer cut him off and he had to brake hard...then he said the steering wheels become uncontrollable and it veered off the road to the left at 45mph...just missed one tree and hit another tree head on. The tree was young and snapped when the car hit it, but it was strong enough that is totalled the car. Impact of the tree would be comparable to hitting a street light post at about 18mph..thats the amount of give Id say it had...if you can imagine what Im saying. Lots of people are skeptical about what really happened that day...some say FWD cars don't just "lose" control that easily..especially if you aren't driving aggressively.

In my head, I imagine boosting around this borad right curve...maybe going 60mph and over adjusting the wheels to help hold the line on the road while understeering...then when cut off...brakes applied...front wheels snap but are over corrected...car jars to the right and he could have overcorrected left sending him off the road. I've felt understeer in our cars and what it can do...and thats what I imagine...but hes a good friend of mine and says that wasn't the case.

I dont think anyone will ever know EXACTLY what happened...but its history..so it is what it is.

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s