I will be running a HRC Stage 2 turbo kit at 5 to 7 psi with stock injectors (for now), a Vortech SFMU, and HRC's inline fuel pump. Can someone tell me what fuel pressure I should be running under full boost with this setup?

I recently posted a question about what disk in the Vortech to use and for my setup I was recommended the 2.72 disk. I also know (correct me if I am wrong) that the static should be set around 57 so that once the vacuum line is connected it drops to the neighborhood of 47-50 psi (standard idle pressures for 420a).

My other question is this. I've also been told that under full boost with this setup (using the 2.72 disk) I should see between 80-90 psi of fuel pressure. Looking at the chart from vortech engineering mapping the disks with static fuel pressure vs. boost pressure it doesn't seem that the 2.72 disk would allow that high of fuel pressure under boost.

Thanks for the help,
Kurt

>I will be running a HRC Stage 2 turbo kit at 5 to 7 psi with
>stock injectors (for now), a Vortech SFMU, and HRC's inline
>fuel pump. Can someone tell me what fuel pressure I should
>be running under full boost with this setup?
>
>I recently posted a question about what disk in the Vortech
>to use and for my setup I was recommended the 2.72 disk. I
>also know (correct me if I am wrong) that the static should
>be set around 57 so that once the vacuum line is connected
>it drops to the neighborhood of 47-50 psi (standard idle
>pressures for 420a).
>
>Thanks for the help,
>Kurt


Full idle vacum (around 15-18 hg's) fuel pressure should be around 50 psi. (47-55 is fine). At 6 psi of boost, you want around 90 psi of fuel pressure. You got the right disk, and be sure to use the short, dark sprind in the SFMU. You might want to use the bleedvalve on the SFMU to fine tune you boosted fuel pressure, as the 2.72" disk may give a bit too much fuel for 6-7 psi. The bleed valve off of the Hahn FPR will be an exact fit for the SFMU, also use the vac check valve on it, just like the Hahn FPR. There is really no need to adjust the SFMU fuel pressure with the vac line unhooked. I just adjusted mine with the car running, and vac line on, and adjusted the static screw until i reaced about 50 psi at idle. When tuning your boosted fuel pressure, be sure to use a digital volt gauge or voltmeter to see what your o2 voltages are, and def keep a close eye on your EGT's. They should not go over 1550 if properly tuned, if they do, then you are just a bit too lean. Shoot for 1550 egt at WOT full boost. If you reach 1600 degrees, back off right away, its too hot.

Thanks for the quick post. I was just reviewing the SFMU instructions on Vortech's website and it didn't seem that the pressure could get that high. I realize that the chart is showing static pressure (at 35 psi) vs. boost but subtracting 7 or so psi from the static will give you the numbers with the vacuum line connected. I also realize that the chart starts at 35 psi which needs to be moved up. I was replotting the lines with the correct numbers for our motor (static at 57 or so) and it just didn't seem to get to 90 psi of fuel pressure.

I have ordered the harder spring, will set it up according to your advice, and tune from there. Thanks man.


Here is what I am looking at:
http://www.vortechsuperchargers.com/pdf/manuals/superfmuim.pdf

>Thanks for the quick post. I was just reviewing the SFMU
>instructions on Vortech's website and it didn't seem that
>the pressure could get that high. I realize that the chart
>is showing static pressure (at 35 psi) vs. boost but
>subtracting 7 or so psi from the static will give you the
>numbers with the vacuum line connected. I also realize that
>the chart starts at 35 psi which needs to be moved up. I
>was replotting the lines with the correct numbers for our
>motor (static at 57 or so) and it just didn't seem to get to
>90 psi of fuel pressure.
>
>I have ordered the harder spring, will set it up according
>to your advice, and tune from there. Thanks man.
>
>


Yeah, the actual rise rate of the SFMU is just a bit more than what that manual says. I too thought it wouldnt go that high, but it does. Also, that manual states the rise rate with the long, silver spring installed, wich may effect the actual rise rate with the short, dark spring. Hahn recomends 80-90 psi of fuel for 6 psi of boost. 90 psi of fuel should be plenty for 6 psi on stock injectors, but i would always start off rich then tune down from there. After using a Datalogger to tune my car, i will always recomend using one to fine tune with, as it is a GREAT tool for tuning. Knowing exactly what the ECU is doing is priceless. Good luck :thumbsup

use the 2.72" with the dark colored springs. set static at 47-55, that should be good for 6psi to get you at 85psi of fuel at 6psi of boost. or you can use the 3.62" dark colored spring, static at 47-55, and using the bleed valve a bit works best for about 8-9psi on hard pulls. this is on stock injectors..
cool


Michael 99gs
HRC Stage 2
Stage 3 process begins anyone got a 420a block thats not spun/head for sale?

http://www.dreamwater.net/purplebeast

Right now I'm running about 8psi, stage 2, fmic, walbro 255 and the hrc fpr, at 65psi of fuel. Should I raise it more? I can tell that I run rich at times but for the most part at WOT I run lean. Any advice?

I am having the same problem as Jasvb TS2K2. I have the stage 2 HRC, walbro 255 running at 60 and it still seams lean at WOT. If anyone has any suggestions that would be great. Later

>Right now I'm running about 8psi, stage 2, fmic, walbro 255
>and the hrc fpr, at 65psi of fuel. Should I raise it more? I
>can tell that I run rich at times but for the most part at
>WOT I run lean. Any advice?
>

Wait! You only have 65 psi of fuel for 8 psi?? Am i getting that right? If so, then thats waaayyyy to little fuel. On stock injectors, to run 8 psi on the Hahn kit (s16G), you need about 110 psi of fuel, give or take a little. I hoping you have larger injectors :wary

Well an issue I must deal with as soon as I get my boost gauge back from Autometer... But I guess I will definately have to turn up the fuel pressure. And no I don't have bigger injectors...still stock.

Guys sorry for the newbie questions but I can't go back to the shop that installed my kit. How do I adjust the FPR? I have the billet one and supplied gauge that came with the kit. I'd appreciate it and any other tips to raise the fuel pressure. TIA

>Right now I'm running about 8psi, stage 2, fmic, walbro 255
>and the hrc fpr, at 65psi of fuel>

Where's you inline fuel pump?? Stock injectors?

8 psi of boost requires 100-105 psi of fuel pressure.

Also, use an inline fuel pump. Read the discussion above. http://forums.2gnt.com/dcforum/DCForumID16/5089.html

Sorry I didn't clairify that I have the inline high flow Walbro 255. But I did read those post and they do make a great argument. I guess injectors and an S-AFC are required for stable fuel pressures at about 90gph and higher. But if you do the switch than you wouldn't have to go so high on the fuel, right? Well lloks like I better start overtime again...

Originally posted by Jasvb TS2K2
Sorry I didn't clairify that I have the inline high flow Walbro 255. But I did read those post and they do make a great argument. I guess injectors and an S-AFC are required for stable fuel pressures at about 90gph and higher. But if you do the switch than you wouldn't have to go so high on the fuel, right? Well lloks like I better start overtime again...

no..tuning with safc is bad unless your just adjusting idle pressure.Tune with your sfmu or fine tune with a bleeder valve mod

Date man....Date.

Originally posted by Slo2g
Date man....Date.

Holy crap this threads old haha oopsy daisy

Originally posted by KTECLIPSE
I will be running a HRC Stage 2 turbo kit at 5 to 7 psi with stock injectors (for now), a Vortech SFMU, and HRC's inline fuel pump. Can someone tell me what fuel pressure I should be running under full boost with this setup? I recently posted a question about what disk in the Vortech to use and for my setup I was recommended the 2.72 disk. I also know (correct me if I am wrong) that the static should be set around 57 so that once the vacuum line is connected it drops to the neighborhood of 47-50 psi (standard idle pressures for 420a). My other question is this. I've also been told that under full boost with this setup (using the 2.72 disk) I should see between 80-90 psi of fuel pressure. Looking at the chart from vortech engineering mapping the disks with static fuel pressure vs. boost pressure it doesn't seem that the 2.72 disk would allow that high of fuel pressure under boost. Thanks for the help, Kurt

For any tech questions call HRC tech support at 630-553-1696 between the hours of 4:23 and 4:29pm Central standard time. If you call inbetween these times and don't get a hold of anyone, please try your call again in a few days so that they may ignore your call again.


I am glad I could contribute to the HRC sporting community.