Author Topic: What size injectors???? (Read 5177 times)

nickmpower · « **on:** March 24, 2007, 04:16:28 PM »

what size injectors do you guys think i should run??? ive got stock, 19's, 21's and 24's to choose from. I have a 2.1 liter motor with reground cams and ported 3 angle head. I recall febi using 24's with a higher fuel pressure but that seems like too much. Using the displacment the 21s seem like they will be the best match.

Febi Guibo · « **Reply #1 on:** March 25, 2007, 01:11:54 AM »

Jah, it was a precautionary thing to avoid leaning out, although I've had no problems and my fuel economy actually went up a bit.

Do you have one of those lambda (a/f ratio) meters? that will pretty much tell the whole story.

nickmpower · « **Reply #2 on:** March 25, 2007, 02:22:17 AM »

yes, but i dont want to have to keep taking the manifold on and off. are you sure they are 24's?

nickmpower · « **Reply #3 on:** March 25, 2007, 03:54:36 PM »

A guy on bimmer forums installed 21's i think in his motor that he did high comp cams and worked head, but no change in displacment and his wouldnt even run.

But i guess im going to go with the 24's, any more opinions?

BrandC · « **Reply #4 on:** March 25, 2007, 11:59:41 PM »

Just do homework on some 2.0L vehicles with similar compression. See what fuel pressure and injectors they are running, especially if they are tuned engines.

nickmpower · « **Reply #5 on:** March 26, 2007, 01:21:01 AM »

it seems the s14's are about 22.5, so maybe i should go with the 21.5's

Gunni · « **Reply #6 on:** March 26, 2007, 03:28:25 AM »

What HP range does your engine cover?
Then I�ll tell you what to get

nickmpower · « **Reply #7 on:** March 26, 2007, 10:21:20 AM »

i have no idea. id guess a little less then the s14 at this point.

m47 crank, 86.5mm pistons, 10:1 compression (i may get a dasc in the future plus i want the engine to last a long time) lightly ported head, 3 angle valve job, metric mechainc springs and retainers, lightweight lifters. supersprint replica header, reground cams but will upgrade to metric mechanic eventually, plus a miller MAF real soon. every moving/wear part replacd.

Gunni · « **Reply #8 on:** March 26, 2007, 01:14:59 PM »

so your hoping for about 200hp?
Use the 24�s.
the others are just to small for that level.

nickmpower · « **Reply #9 on:** March 26, 2007, 01:53:06 PM »

im guessing it will probably be 180-190

bmwman91 · « **Reply #10 on:** April 10, 2007, 10:27:42 PM »

The stockers are 20.35# units. They seem to be good up to ~155bhp. Just going on the assumed increase in power...

(X#/20.35#)= (190bhp/155bhp)
=> X = (190bhp/155bhp)*20.35# = 24.9#

So, usung the ratios (crude way of doing it), you should look for some 25# ones. 190bhp would probably be about their limit. Hope this helps.

vjlax18 · « **Reply #11 on:** April 11, 2007, 08:11:57 AM »

Built S52's run 24# up to 100hp/ltr, so the M42 which is a baby M50 should run the same with 95hp/ltr

nobrakese36 · « **Reply #12 on:** April 12, 2007, 12:55:54 PM »

24 seems a little big, i talked to ireland eng. They said stock 19 or 20 lbr's are fine with higher fuel pressure.

Tor Arne Kaasen · « **Reply #13 on:** April 13, 2007, 03:21:16 PM »

200 hk = 277cm3 #26,3 190hk = 263cm3 #25 etc. this is at 90%
140hk =#18,51 194cm3
19 or 20 Lbr at 4 bar = 165hk to smal for 200hk

Author Topic: What size injectors???? (Read 5177 times)

vjlax18