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View Full Version : Double injector rail


Bas325
03-31-2004, 06:33 AM
Hi,

Does anyone have experience with installing a double injector rail on a M20 engine?

If so, pics would also help alot.

Bastiaan

felixthecat
03-31-2004, 07:43 AM
are you saying what i think here ....ive never heard of one???what is the benifit?????what manifold do these require???im lost..

Bas325
03-31-2004, 01:26 PM
Felix,

If you install an extra injectorrail with off course 6 injectors your engine will get more gasoline. I am building an 323i Turbo engine and when you want more power you also need more gasoline.

I want to get there by installing an extra rail. A friend of mine did it on his M10 engine and you really feel the difference.

A friend of mine will than change my computer, so it can handle the extra injector rail.

I only do not know what the best place is to install this onto my intake.

Bastiaan

diegom6
03-31-2004, 01:30 PM
Originally posted by Bas325
Hi,

Does anyone have experience with installing a double injector rail on a M20 engine?

If so, pics would also help alot.

Bastiaan

Bastian I tired to send you a PM but your mail is full, clean it, sorry for the delay in responding your questions...yeah off topic!

chromius
03-31-2004, 01:39 PM
Originally posted by Bas325
Felix,

If you install an extra injectorrail with off course 6 injectors your engine will get more gasoline. I am building an 323i Turbo engine and when you want more power you also need more gasoline.

I want to get there by installing an extra rail. A friend of mine did it on his M10 engine and you really feel the difference.

A friend of mine will than change my computer, so it can handle the extra injector rail.

I only do not know what the best place is to install this onto my intake.

Bastiaan

Why go through all that trouble? you would have to drill new ports for the extra injectors etc...and I have never heard of anyone doing that before....:confused: Why not just get some larger injectors, and couple that with an adjustable fuel pressure regulator...it would have the same effect.

edit: also I'm not even sure that would work very well at all, because the spray patterns of the injectors would interfere with one another, you would get very ineffefciant cumbustion, and possibly damaging detonation (or "ping")

BMW_M52_M20
03-31-2004, 03:42 PM
I am trying to understand why you wouldn't just go with bigger fuel injectors? Seems a lot of work to add another rail and with what benifits?
Jay

MorningCruiser
03-31-2004, 05:08 PM
Bigger injectors...

Ford 19# ones work don't they? :D

chromius
03-31-2004, 05:18 PM
Originally posted by MorningCruiser
Bigger injectors...

Ford 19# ones work don't they? :D

Yeah I think they are a direct replacement. Bosch part number 280-155-909 I believe....19.6LB Should be more than enough

Skunk#1
03-31-2004, 05:59 PM
i have seen this before, but the other rail is totally secondary. basically you should just go bigger injectors with regulator. most of the applications that i have seen this was strictly on race applcations. most of the time the secondary injector accually face the opposite way than (upstream) the primary injectors. really all it does is uses boost pressure the same way tyhe regulator does to meter in extra fuel, only using extra injectors instead of bigger ones. it all depends how deep your pockets are. pressure regulator and bigger injectors=$x. duel rails=$x+a hell of a lot more money. *drink*

felixthecat
03-31-2004, 06:13 PM
what are you planning here 50 psi of boost or something crazy????

MorningCruiser
03-31-2004, 07:13 PM
Unless you're running Alky or something, what the HELL do you need a second rail for? It'd be cheaper and easier to run 19# Fords...

snd84318i
04-01-2004, 02:05 AM
with the ford injectors in lets say the m10 motor with first starters a fuel presure reg and more air flow and better exit flow . would you need a stronger fuel pump . would this cause problems with the air/fuel mix . should you only change the injectors if your turboing it up ?

chromius
04-01-2004, 02:31 AM
Originally posted by snd84318i
with the ford injectors in lets say the m10 motor with first starters a fuel presure reg and more air flow and better exit flow . would you need a stronger fuel pump . would this cause problems with the air/fuel mix . should you only change the injectors if your turboing it up ?

with the 19LB/hour injectors you are good for about 40hp/cylinder, and unless you are running FI with pretty high boost, the stock fuel pump will probably be fine. I think as long as the fuel rail stays at 35-45psi you are fine....and you can check this by sticking a fuel pressure guage on the pressure regulator.

felixthecat
04-01-2004, 02:35 AM
Originally posted by snd84318i
with the ford injectors in lets say the m10 motor with first starters a fuel presure reg and more air flow and better exit flow . would you need a stronger fuel pump . would this cause problems with the air/fuel mix . should you only change the injectors if your turboing it up ? um the stock pump is capable of 80 psi...

Bas325
04-01-2004, 08:05 AM
Thanks guys,

I think I will just get bigger injectors if I listen to all your stories.

Thanks for the input.

Bastiaan

MorningCruiser
04-01-2004, 08:07 AM
19# injectors ONLY good for 40hp/cyl? Are you CRAZY?

:|

haha That's only 160hp... That's pretty weak, considering that most guys can run their mustangs up to 375 with 19# injectors!

snd84318i
04-01-2004, 12:06 PM
Originally posted by felixthecat
um the stock pump is capable of 80 psi...
kool didnt know that thought just 60 . havent decided yet on motor job v8? m10 stock rebuild ? or old m10 carb setup ? these are what im thinking about . if i buildup the m10 with these injectors , would i need to do everything else first . like header and exhaust and fuel presure reg ? or can i put them in lets say right now and there would be no difference in the power or fuel consumption , just have it ready for the build up later ?thanks

chromius
04-01-2004, 01:42 PM
Originally posted by MorningCruiser
19# injectors ONLY good for 40hp/cyl? Are you CRAZY?

:|

haha That's only 160hp... That's pretty weak, considering that most guys can run their mustangs up to 375 with 19# injectors!

um...you are right...but how many cylinders...?

edit: actually if they are running 375hp on 19LB/hr injectors even on an 8 cyl engine with about 45psi in the fuel rail thats still only 320hp....therfore the injectors would be running at 100% duty cycle...which is horrible....max they should run at is 50-70%

chromius
04-01-2004, 01:54 PM
and actually I just worked out the math, and at 375hp with 8 cylinders, 45psi at the rail and 80% duty cycle, the absolute minimum would be 25.92LB/hr injectors! And if its 6 cylinders its 34.57LB/hour:P

chromius
04-01-2004, 02:03 PM
Originally posted by MorningCruiser
19# injectors ONLY good for 40hp/cyl? Are you CRAZY?

:|

haha That's only 160hp... That's pretty weak, considering that most guys can run their mustangs up to 375 with 19# injectors!

and actually I'm not crazy...maybe the guy that invented MATH is crazy! or maybe its the guy that invented physics! or the guys who invented volume and flow rate.....I don't know maybe its all one big conspiracy to get people to buy the wrong injectors?:moon: