The TRUTH about FFV injectors..

[Una]

They ARE NOT +25's, and possibly not even +20's! as some have recently said. I back up this claim with this site:
http://www.injectorservices.com/Flow...0280150834.jpg
328cc at a 3bar 3bar = 44.1psi (3*14.7)
328/44.1 = 7.43cc per psi of fuel pressure
7.43*55 = 409cc
409/10.5 = 38.959lb injectors at our fuel pressure.. Just barely 39lb injectors!

These might be great if your running a safely rich cal (won't name any vendor's names), but if you're like me running a custom cal, you're going to be a touch lean. Now they are still quite a bit better than the stock 33lb T2 injectors, but they're not 42lb +20 injectors.. Now if you have an AFPR, simply raising the pressure 5more PSI will get you to where you need to be, at 60psi, they ARE 42lb injectors..

Anyone care to rebut me? I posted all my math...

[Una]

I just checked that site again, they say they test the injectors at 43.5psi, so I was a touch off.. Still only gets it up to 39.5lb/hour at our pressure.. Also, their numbers are an actual flow bench's numbers.. Not what the book says.. That may be why everyone else was wrong, as these are real world numbers. Anyone got the numbers off a real set of +20's, or +40's to look up on that page and see how they compute?

[tryingbe]

Can you explain to me why +20% injectors are 20%, +40% are 40%?

(42-33)/33=27.2727.... %

+40% injectors
(52-33)/33=57.5757...%

[Una]

hehe.. Funny math there.. I wondered that once too..
42lb (+20 injectors) * 20% = 8.4lb, 8.4lb + 33lb is 41.4lb
52lb (+40 injectors) * 40% = 20lb, 20lb +33lb is 53lb.. They're rough numbers, the percentages are rounded.. And the math is screwy.. But when I scale the fuel tables down by the advertised amount, things work great.

[MiniMopar]

In reality, some "Super 60" injectors flow more like 58pph. A few folks have had their's flowed to verify this and I have found that I've had to scale things by that amount to get in the ball park of the center line in the auto cal cells. If you do the math, you find that 58pph is about +40% of 42pph. So really, they are +75% of stock T2 injectors. I just ignore the wacky percentages and go strictly by the flow rate.

[daytonaturbo87]

I dunno, 33lb * 1.2 = 39.6lbs That would mean that the ffv injectors flow 120% of what a T2 injector flows. Is that not a +20%???

[Una]

If they're +20's, what are the 42lb ones the vendors sell as +20? heh.. Anyone got the number off the side of a set so I can look them up on that site too.

[daytonaturbo87]

If they're +20's, what are the 42lb ones the vendors sell as +20? heh.. Anyone got the number off the side of a set so I can look them up on that site too.

I dunno, just stands to reason that percentages should only be used as a rough guide and that an actual flow rating of an injector should be used when considering a new calibration. It's easier to comprehend talking about it as a percentage, but really not accurate at all, seeing as there's no concrete way of determining these percentages.

[Mike_Shepard]

Not to go too far off topic but I have recently installed a FFV fuel rail and FPR on my TII and was told that they didnt have enough pressure for a turbo car but after doing some cross refferencing it looks to be about the same static pressure at Idle 55pph but for some reason I dont have a FP gauge nor a A/F gauge so I cannot tell if im rich or lean

[Frank]

I dunno, just stands to reason that percentages should only be used as a rough guide and that an actual flow rating of an injector should be used when considering a new calibration. It's easier to comprehend talking about it as a percentage, but really not accurate at all, seeing as there's no concrete way of determining these percentages.

Bingo! Because for all intents and pruposes here, the FFV are equivelent to what we would call +20's. They are close enough and I dont think anyone has ever said they are exactly the same but rather used the words... about.



Frank

[Una]

That's cool.. I got a set of +20's at the junkyard for $6.. hehehe.. I'm not complaining.

[inmyshadow]

Well today I found a FFV car in the junkyard. So I grabbed the fuel rail, injectors and wiring. I figure I'll send out one of the injectors for testing. I'd like to get some concrete numbers myself.

Also....

I swapped to a FFV rail/FPR months ago. I thought it might be a problem, but I looked at the FPR. They have the same rated PSI etched in them.

So as scienific as I got. I installed it. Watched the wideband. Then listened to see of the motor was going to go boom.

I've been running 20lbs of boost on FFV fuel rail and FPR for 8months now. Just found another today too.

Not to go too far off topic but I have recently installed a FFV fuel rail and FPR on my TII and was told that they didnt have enough pressure for a turbo car but after doing some cross refferencing it looks to be about the same static pressure at Idle 55pph but for some reason I dont have a FP gauge nor a A/F gauge so I cannot tell if im rich or lean

[Mike_Shepard]

Thanks for the info James here is a pic of mine, At that point it was not fully installed

[Una]

I grabbed the FFV rail/regulator as well. Dunno how I'll hook that nice stainless like to my stock hardline.. And the return stainless didn't want to release, so I cut it.. I figure I can just unscrew the hardline coming out of the stainless regulator and put in a normal return line..

[Mike_Shepard]

Brian what I did was cut the FFV Fuel line under the car at the floorboad then used compression fittings to splice them togeather

[nomadman2001]

It took me a long time to figure this one out..........
You have to work things backwards;
42pph x 20% = 8.4, 42pph - 8.4 = 33.6
52pph x 40% = 20.8, 52pph - 20.8 = 31.2

at least this is how I understand it.

Can you explain to me why +20% injectors are 20%, +40% are 40%?

(42-33)/33=27.2727.... %

+40% injectors
(52-33)/33=57.5757...%