Ok I am going to be running 9LBS of Boost on a Stillen V2 Kit with a walbro 255lph FP and I heard I need to upgrade my disk to run 6:1.

2 Questions.
#1 - Is this true
#2 - Is this what I want to be buying? http://www.vortechsuperchargers.com/...tegory_Code=FC

 

Man the FI forums have been dead lately... BUMP

 

Isn't the 6:1 disk the one that comes with the 3.6" pulley? You might want to start with the 8:1 disk just to be safe (rich). If you are way rich you can lower afr with AFC.

 

Is there any way to tell which kit I have, considering I bought the kit second hand for someone who is car-retarded.

 

lol yea if u open the fmu top, u can measure the diameter of the disc inside and it will tell u what ratio FMU u have. I forget the measurements and what means which but i think mine was 2.2" and i'm 8:1.

 

Does anyone have the measurements?

 

that should be in the stickies part if it isn't

chris why dont you try the vortech sfmu

since you are going with the walbro, you are going to need a fpr anyway and that integrates the two of them together.

 

I just got a Vortech Super FMU off ebay for $132 shipped. Now, I just need to find a BOV.

 

wow, good deal. I just got a Blitz DD supersound BOV for 100$shipped on ebay

 

nice, thats cheaper than buying the two separate. you dont really need to have the bov, it just sounds cooler.

 

I'm leaning towards a Vortech Race BOV. I know I'll need to get a new flange welded on but that shouldn't be a big deal.

 

Man this supercharging is starting to get expensive! Now I need to get a SFMU because I am going with the walbro255lph fuelpump. Anyone know where I can get a good deal, or should I just be on the look out on eBay?

 

Once you start boosting, it never ends.

But if you intend to stay at 9 psi, you can get by with just a 6:1 disk in the fmu that came with your kit, and no need for an adjustable fpr or super fmu.

The additional fuel pressure from the Walbro pump will only help to ensure a little extra richness at WOT, and the fuel pressure will not be so high at idle or cruising that your ecu can't compensate. I installed my Walbro pump several months before installing my SC kit, and I had absolutely no problems with the extra 6 psi or so of fuel pressure.

 

Thanks Stephen (again) - Well I would like to get the best, considering I ran into a good deal and have some money to play with (unusual for a full time college student). Would it be a better idea to get the SFMU rather then the disk?

 

wait, isnt the disk an FMU too? what is benefit of an SFMU?

 

grrrr....this whole supercharging thing is confusing

 

The disk is part of the fmu. The size of the disk controls the rise rate (increase in fuel pressure per increase in boost pressure) of the fmu.

Adjustable fmus, like the Vortech super fmu and the Cartech fmu have rise rates that are adjustable using adjustment bolts, and they also have a bleeder valve to vary the amount of boost pressure that the fmu sees. So with an adjustable fmu you can vary the rise rate and the fuel pressure at zero boost.

Think of the equation for a line, Y = mX + b. Y is the fuel pressure we want to achieve, X is boost pressure, m is the rise rate, and b is the fuel pressure at zero manifold pressure. With a non adjustable fmu the only thing you can change is m, by changing the disk size. With the adjustable fmu you can change m and b. m is controlled with the bleeder valve, and b is controlled with the center bolt (on the Cartech unit, I don't know about the sfmu).

 

There is a lot to know, but you can pick up the basics pretty quick by staying tuned to this forum, and by reading some books.

Two fairly good books written for people new to boosting are Supercharged and Maximum Boost, both by Corky Bell (founder of BEGI, the company that makes the Cartech fmu).

 

the stock fmu for the v2 is 8:1 its pushing 7-8 lbs of boost and the 255 should work fine with it. . im running 9lbs with 8:1 fmu and 255 walbro with no problems what so ever. if you go over 9lbs then it does get confusing but mecca is running 11lbs with stock fmu and his car ran well with it also.

 

until the butterfly screws fall into your motor

 

ok, I was under the impression i need an adjustable FPR to run the Walbro. So looks like the electronics i will be buying at the SAFCII. Is there any way to make sure I am running 8:1 disk?

 

Adjustable FMU's will allow you to more precisely tune, allowing for better hp/tq.

They really are a good investment. T

he SAFC is really only good for bling factor and for fine tuning....it's not as helpful as the Adjustable FMU because it only cahnges injector pulse width, not actual pressure.

A CArtech and SAFC together, however - dynomite!

 

how much can u find a Cartech FMU for? also the screw had nothing to do with Boost , just bad luck i guess....

I had stock FMU and upgraded fuel pump on 11 psi pulley

 

I've seen the cartech go anywhere from 140-200 shipped. I personally paid 150 shipped.

The cartech is aka the Begi rising rate regulator.

 

Thanks for the great info guys, I'm going to be looking on eBay but does anyone know other websites that have good prices?

 

I have a SC'd 01', with a 3.48 pulley...what would be the best set-up to go with in terms of pump and fmu? I see alot of info for 95-97's but not much on my year.

 

i dont want to waste space by making another thread so ill just post here. where can i find info about calculating what kind of disk i need in the vortech unit? ill be running 9lbs turbo and from seeing other peoples setups, most have an 8:1 disk. im pretty confident that will work but i want to understand exactly how to figure out what disk is needed regardless of application. i would search but it wont let me - ive been attempting to search on google for a while now but to no avail. thanks.

 

8:1 for example gives you a 1lb of fuel per boost so its good to 8lbs maybe nine but not more than that. im running 8:1 with 9lb boost s/c the risk is very slight but doable if you monitor your gauges properly.

 

??? An 8:1 disk gives 8 psi of fuel pressure increase for every 1 psi of boost pressure. So at 9 psi of boost the fuel pressure is going to be 72 psi plus half the base fuel pressure (according to the conventional calculation). So figure on fuel pressure in the 85-90 psi range. This enough for about 340 engine hp using 240 cc/min injectors at 100% duty cycle, assuming a bsfc of .6

 

your right stephen thats what i meant.