450cc Injectors -- What size RRFPR

[big_P]

I thought you were talking about him. He never had the time to finish the dohc project. He even plumbed the turbo's and oil lines and whatnot. The engine is still in his basement, I saw it when I went up to New Hampshire to buy his 543 trans from him.

[m90daytona]

this guy?...http://www.cardomain.com/ride/473368

[gorf1000]

m90, that is the guy I got the turbo kit from, my brother-in-law looked at the turbo and he doesn't see anything wrong so I'm going ahead with the project.

I just snagged a set of Ford red cap 30# and I have a Command Flo unit in myEbay awaiting purchase to handle my base fuel pressure.

So with that I'm still hazy on how to figure out what my RR FPR should be, I guess I'm still unsure of exactly what I'm aiming to reach if I want to run at 8-9 lbs of boost what top end fuel pressure should I be looking at.

I'm not sure if I'm correct so someone please let me know if this is wrong but we'll say that I run a base fuel pressure of 28psi as m90 recommended earlier and I want to run 9lbs of boost.

The RRFPR's rise at a fixed ratio of fuel pressure to pound of boost, so a 4:1 would give 36psi fuel pressure at 9lb boost plus the 28 base psi totalling 64psi at full boost, correct? If that's right then a 6:1 would create 54 psi for a total of 82 psi at full, and an 8:1 would create 72psi for a total of 100psi at full boost.

Assuming I got that right I'm not sure now what my ideal pressure should be. Playing with the injector calculation page that I was pointed to I see that guessing 325 crank hp and 82psi (the 6:1) should put me at 0.61 Brake Specific fuel consumption, 100psi (the 8:1) would put me at 0.67 which is higher than is recommended. However since I really have no idea how much horse power I can really expect here I'm not sure whether it's better to guess high or low.

Any suggestions?

[mwinkle353]

Get a BEGi fully adjustable unit. It'll have two adjustable settings. Just make sure it's got the two, and not one.

[Ondonti]

Those ratios arent much help until it comes down to actualy tuning the car. Its safe to assume that 6:1 or 4:1 will probably not be good enough of number to go with unless you want the car to run rich or lean under boost. Thats why the BEGI rocks.

[gorf1000]

Any thoughts on this Vraxx FMU or this Generic

I can't find any info on Vraxx so I'm not sure what I'm getting into with that.

I sent a message to the one selling the generic RR FPR and he says it's adjustable but at a 1:1 ratio, isn't that just an adjustable FPR?

In response to the above about the BEGi systems, I looked into them but you can only buy them direct from what I've found right now and for 300 I'd rather look to spending a little extra and get an AFC or something. The other cartech units are also supposedly adjustable RR FPR's but now I'm not sure exactly how that works since I thought the point of a RR FPR was to rise at an offset ratio after boost not a 1:1.

[Ondonti]

If you dont understand then its time to slooooow down before purchasing anything.

[mwinkle353]

This is the BEGi unit you should be looking for!!!!! It's old name is Cartech. Same guy, same company.

http://cgi.ebay.com/ebaymotors/CARTE...QQcmdZViewItem




And here is another one.

http://cgi.ebay.com/ebaymotors/Turbo...QQcmdZViewItem

[gorf1000]

Quote:

If you dont understand then its time to slooooow down before purchasing anything.

That's why I'm here, I'm trying to make sense of it all.

[m90daytona]

whats the advantage of that over the vortech sfmu that does both base and boost? it seems w/ the cartech you still need a fpr for base pressure.

[Ondonti]

BEGI/cartech is infinitly adjustable and therefore you can actually get a decent tune.
it is also the only unit that can adjust when fuel pressure actually starts to increase. If you like running lean or way to rich on the first few psi boost then be my guest.

[m90daytona]

Quote:

Originally Posted by Ondonti BEGI/cartech is infinitly adjustable and therefore you can actually get a decent tune. it is also the only unit that can adjust when fuel pressure actually starts to increase. If you like running lean or way to rich on the first few psi boost then be my guest.

wrong, i dont know where your getting your information but thats not accurate...the sfmu has many adjustments including

1. when you want the fuel pressure to start to increase. for instance, you can make the fuel pressure increase start at 5in vac instead of 18

2. you can make the fuel pressure stop increasing whenever you want. for instance, if your running 15psi boost, you can stop the fuel pressure from rising at 10psi boost and hold steady to 15.

3. the bleed screw lets you lower the curve no matter whet disc you use. for instance, if a 4:1 disc is to much, and a 3:1 disc is not enough, you can use the 4:1 disc, adjust the bleed screw and it will act as like a 3.5:1 for you. its almost infinitly adjustable.

here are some more FACTS about it http://www.vortechsuperchargers.com/.../fmu_sfmu.html

scroll down alittle to view the functions of the sfmu...and it does base pressure so theres no need to buy a fpr and fmu.

[Ondonti]

yay for almost!!!!

That doesnt even sound like the same thing as far as that point of increase

[m90daytona]

Quote:

Originally Posted by Ondonti yay for almost!!!! That doesnt even sound like the same thing as far as that point of increase

huh? can someone explain what this means?

[Ondonti]

Point of increase is important when transitioning into boost.......now where it starts increasing 1:1 in vacuum.