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View Full Version : Larger injectors for 502 mag



Dream Warrior
04-09-2009, 01:15 AM
I'm tring to find out if anyone might know where I might be able to find a larger injector for my 502 mag mpi. My engine is modified and supercharged, and I think I may need a larger injector to keep up with my fuel needs.

Pachanga
04-09-2009, 08:31 AM
If a 502 has the same injectors as the 496 I have a bigger set. Bought a raylar kit from a guy and he was experimenting with larger injectors. I went with Ray's sound advice and kept the stock injectors! I have not identified them! I believe he bought them through GM.

Ratickle
04-09-2009, 08:33 AM
I'm tring to find out if anyone might know where I might be able to find a larger injector for my 502 mag mpi. My engine is modified and supercharged, and I think I may need a larger injector to keep up with my fuel needs.

Are you checking EGT's ?

Warlock28SXT
04-09-2009, 10:23 AM
Are you checking EGT's ?

and/or AFR's

MERPerformance
04-09-2009, 09:19 PM
Call Mark@ Precision Marine, I'am sure he would know.

boomer35
04-09-2009, 09:22 PM
i have 2 stock sets out of a merc 500EFI, 38psi, all in great shape, i went to a 48psi.... make me an offer if you can use them

Offshoredrillin
04-09-2009, 10:04 PM
I too have 2 sets of stock off of a 500 efi, but if you are running supercharged you may need higher, I went up to 55lb high impedance. I second calling Mark at precision. if you need stock ones let me know

YoungPerformance
04-12-2009, 02:44 AM
Which injectors do you have? Are they the Kiehin injectors? If so, they do not make any larger ones. You will have to modify the rails and manifold to accept a different style injector. I have done this several times and make it accept up to a 65lb injector. Give me a call if you have any questions. Thanks, Eddie.

Griswald
04-12-2009, 11:00 AM
Which injectors do you have? Are they the Kiehin injectors? If so, they do not make any larger ones. You will have to modify the rails and manifold to accept a different style injector. I have done this several times and make it accept up to a 65lb injector.

Isnt' there another brand that will fit without modifying anything?

OffshoreDrillin - what brand did you go with to get the 55lb?

Dream Warrior
04-16-2009, 12:43 AM
I pretty sure there is a larger one. I seem to remember seeing a ad last year for a 55lb injector to fit my manifold, but I cant remember who was making them.

Offshoredrillin
04-16-2009, 09:19 AM
Isnt' there another brand that will fit without modifying anything?

OffshoreDrillin - what brand did you go with to get the 55lb?marren, they fit the stock rails perfect. http://www.injector.com/

Griswald
04-16-2009, 10:29 AM
marren, they fit the stock rails perfect. http://www.injector.com/


what part #?

YoungPerformance
04-16-2009, 12:22 PM
It all depends on what injectors are in it now. They used the Keihin injectors until 1999 I believe. There are no larger injectors that will drop in without modifying the rail and the manifold.
Eddie

Griswald
04-16-2009, 06:22 PM
There are no larger injectors that will drop in without modifying the rail and the manifold.
Eddie

I hear conflicting stories on this from just about every person I come across.

Offshoredrillin
04-17-2009, 08:00 PM
mine fit perfectly on a 500efi, not sure about the Mag and the fuel rail, just give them a call and see what they say. they were great to work with.

YoungPerformance
04-19-2009, 02:11 AM
I hear conflicting stories on this from just about every person I come across.

Now to be clear, I am referring to the MPI's that came with the Keihin 42Lb(I believe) injectors. I think they used them until around 98, at which time they switched. There are no replacements for the Keihin's. I am not sure about the later year MPI's if there is a replacement injector or not.