Just wondering what size injectors most of you guys are running out there with MSnS?

I have 510cc and 550cc and wasnt sure if either of those were good enough to support my 25psi for next year, as I am still a newbie with my MSnS.

What are you guys using and how much boost, or what do you recommend me to using?

Though I don't have the MS installed yet, I've got 780cc's for it, which should be PLENTY for me. I think at 25psi on your 60-1 you might want to get something around this size.

Originally posted by BlackMagic
Though I don't have the MS installed yet, I've got 780cc's for it, which should be PLENTY for me. I think at 25psi on your 60-1 you might want to get something around this size.

You read my mind, thats what I was thinking of using.

510s should max out around 350ish hp.

I'm only runnin green top 440's right now on a T3, but gettin ready to bolt on a 60 trim and definitely lookin for somethin in the 780cc range to push 20+ psi comfortably


...got any pics of that 60-1 ?

Chekc out the write-ups on the site about choosing a fuel system, pump, injectors, etc. They are very informative and have all the information you need to figure out what size injectors you need for your car. For example:
25psi with 780cc injectos, with an estimated 400hp:

(from my excel spreadsheet of formula's i made).
CC
Engine Size 1996
Cylinder Count 4
Injector Count 4
Injector Flow (cc) 780
Injector Flow (lb) 74
Rated PSI 43.5
Fuel PSI 40
Vacuum PSI 30
Boost PSI 65
Modified Inj (cc) 748
Modified Inj (lb) 71
Req_Fuel 4.49
Max HP 400
BSFC 0.525
Duty Cycle 85%
Inj CC (base) 551.25
Inj CC (calc) 648.53
Fuel PSI 30.07
Vacuum PSI 20.07
Modified PSI 55.07
Pump (gph) 35.00
Calc. Duty Cycle 73.70%

Bear with me for a few :) Given the average BSFC (brake specific fuel comsumption) of .525, we would require 35gph to support 400hp. So, we can calculat that we would require 551cc injectors at 100% duty cycle to be able to supply this. But, we don't want to run higher than 85% duty cycle, so we will require injectors that are at least 648cc (this is at 43.5psi btw). so, in order to get our 780's to flow like 648 cc injectosr, we would have to set our static fuel pressure at 30psi. This is to low for a good idle (about 20psi at idl), so what we do is modify the static fuel pressure to say 40psi. This will run our injectors as if they were 748cc's, and a duty cycle of 73.7%, which is acceptable. Now, this means we are going to need a fuel pump capable of supplying 35gph of fuel at 65psi (static psi + boost psi), The walbro 255lph supplies 45gph @ 65psi, while the high-pressure version can supply 53gph, either one will surfice, the 190lph can only supply 30gph @ 65psi, which won't give us enough fuel. So, we can see the 780's will support 400hp without issues given a good pump.

Here is another sheet for 660's, just fyi:
CC
Engine Size 1996
Cylinder Count 4
Injector Count 4
Injector Flow (cc) 660
Injector Flow (lb) 63

Rated PSI 43.5
Fuel PSI 43.5
Vacuum PSI 33.5
Boost PSI 68.5
Modified Inj (cc) 660
Modified Inj (lb) 63
Req_Fuel 5.08

Max HP 400
BSFC 0.525
Duty Cycle 85%
Inj CC (base) 551.25
Inj CC (calc) 648.53
Fuel PSI 42.00
Vacuum PSI 32.00
Modified PSI 67.00
Pump (gph) 35.00
Calc. Duty Cycle 83.52%

Now, we would require to run at 42psi, so we would probably just use 43.5 since it's what the injectors are rated at anyways. Now we would have to use a pump that can supply the 35gph @ 68.3psi, again either 255lph pump would suffice, our duty cycle is at 83.5%, which is pretty close to our 85% max we are looking for. The 660's would give us a better idle, but wouldn't leave much room for more power.

The 550's could work, but again let me show you ;).

CC
Engine Size 1996
Cylinder Count 4
Injector Count 4
Injector Flow (cc) 550
Injector Flow (lb) 52

Rated PSI 43.5
Fuel PSI 60
Vacuum PSI 50
Boost PSI 85
Modified Inj (cc) 646
Modified Inj (lb) 62
Req_Fuel 5.19

Max HP 400
BSFC 0.525
Duty Cycle 85%
Inj CC (base) 551.25
Inj CC (calc) 648.53
Fuel PSI 60.48
Vacuum PSI 50.48
Modified PSI 85.48
Pump (gph) 35.00
Calc. Duty Cycle 85.34%

Well, this says we would have to run our injectors at 60psi static, and 85psi under full boost. So, the only option we have is the 255lph hi-pres, beacuse it can supply 40gph at 85psi (always want a little overhead). Or duty cycle is just at 85%, which is acceptable, and our idle would be even bette, however keep in mind these are only estimates and this would be cutting it way to close in my opinion! Also, it really depends on your HP you are shooting for, or at, not sure what you are seeing at 25psi.

Mike I run 550's now and they are good for 20psi if tuned well. You could raise the static pressure to make the react like 780's. Then adjust for fuel req and all that stuff. That would save you a few hundred for a while and give you plenty of room to grow into tuning.

Terry