PDA

View Full Version : Fuel Injectors - M50 vs M52


uber e36
10-01-2006, 07:16 PM
Guys,

Are the fuel injectors for the M52 larger than their M50 counterparts? Anyone know how many lbs either are?

Thanks!

-Geoff

p.s. I searched and could only find info on cleaning injectors...
uber e36
10-02-2006, 12:15 AM
Well I've learned that the S52 had 21#, but still unclear on M50, M52 & S50???

Fuel Injectors
M50: 17.5#
M52: 21.5#
S50: 17.5#
S52: 21.5#

[edited]
kennejp
10-02-2006, 12:55 AM
s52 and m52 both have the pink 21.5# injectors I think the m50 had 16.5 but I am not for sure
uber e36
10-02-2006, 08:54 AM
Thanks! Wonder about the M50/S50? My assumption would be that the S50 had the 21.5# as well....

Edit: on Pelican Parts, both the 325 and M3 3.0 have the same fuel injector part #, so I guess the S50 does not have the 21.5#
1faste36
10-02-2006, 10:51 AM
Both the M50 and S50 had 17.5# injectors and Both the M52 and S52 had 21.5# injectors. The fuel pressure specifications are as follows:

M50/S50 US Engine: 43.5 +/- 2.9 psi
M52/S52 US Engine: 51 +/- 2.9 psi
uber e36
10-02-2006, 05:42 PM
Great info - thanks!

Any idea on why an S50 which is a 3.0L has smaller injectors (and fuel pressure requirements) than the M52 which is a 2.8L?
kennejp
10-02-2006, 06:47 PM
Not exactly sure but I would venture to guess that they just upgraded and made better improvements. The s50 and m50 were made prior to the s52 and m52 so they upgraded the many things one of which was the injectors. The m52 came after the s50 and they improved the injectors. Only reason I can think of off the top of my head
jmitro
11-22-2006, 09:51 PM
Both the M50 and S50 had 17.5# injectors and Both the M52 and S52 had 21.5# injectors. The fuel pressure specifications are as follows:

M50/S50 US Engine: 43.5 +/- 2.9 psi
M52/S52 US Engine: 51 +/- 2.9 psi


so can anybody tell me whether my stock M50 injectors will work well enough with S50 cams? the other mods are ECIS intake, Turner chip for cams, OBDII headers, and UUC exhaust with straight pipe instead of cats.

common sense says they would work fine since the same injectors work in both engines, but i don't want to risk going too lean.

EDIT - ok, according to this thread (http://forums.bimmerforums.com/forum/showthread.php?t=600684&highlight=injectors) the stock injectors should work fine. Makes sense if both engines use the same injectors. Same part number according to realoem.com, so they flow rate should be the same.
theruss1an1
11-22-2006, 11:12 PM
Good thread!

What engine are you building now?

-Serge
FierySphere
11-22-2006, 11:42 PM
Both the M50 and S50 had 17.5# injectors and Both the M52 and S52 had 21.5# injectors. The fuel pressure specifications are as follows:

M50/S50 US Engine: 43.5 +/- 2.9 psi
M52/S52 US Engine: 51 +/- 2.9 psi

I can *assure* you that my '93 US 325is with stock M50TU has a 3.5bar (51-ish psi) fuel regulator. I replaced it recently when I changed the injectors.
jmitro
11-23-2006, 08:23 AM
What engine are you building now?

I'm modifying an M50 engine for JP class club racing, which means i'm installing S50 cams, intake, exhaust, and a chip. this will hopefully give me a good 25-30 hp from what i've read.
onewhippedpuppy
11-23-2006, 08:29 AM
I'm modifying an M50 engine for JP class club racing, which means i'm installing S50 cams, intake, exhaust, and a chip. this will hopefully give me a good 25-30 hp from what i've read.

Please, keep us updated. That's always a popular topic for conversation on here, but very few have actually done it. I'd like to hear some first-hand feedback on it, it's something I may consider in the future.