S52 OBDI Injector Size & Differential

[bdi_fc]

After getting my swap up and running, I've been thinking my car should be a little faster. I know this is all part of the "need for speed." But the car feels almost as fast as my E36 M3 when it should be faster (butt dyno inaccuracies aside).

These are the things I'm considering:

• Injectors
  Right now I'm running the S50 injectors (17.5 lbs/hr?) that are pale green. Shouldn't I be running at least the 21.5 lbs/hr the S52 originally had? Or should I jump to 24 lbs/hr with the Euro HFM? What's the price differential?
• Differential
  I'm running the 3.73 LSD that came stock on my '89 325is. I'm thinking the 3.23 LSD from an e28 would allow the engine to run out faster since I won't be shifting gears every 2 seconds.
• A tired engine
  Is it possible the motor is tired? I doubt it since the motor had 107,000 miles at the time of swap. My M3 had about the same and ran fine.

Thanks!

[trent]

What trans do you have?

[bdi_fc]

I'm using the ZF that was originally attached the S52.

[trent]

You should run a 3.23 or a 3.46 (I think this gearing is ideal)

Do you have cams with your 3.2? I would think you should have at least pink tops.

[1990m3]

definitely get the larger or at least stock size s52 injectors. With the OBDI manifold you will need more fuel I think.

I agree with Trent, you should look for a 3.15, 3.23, 3.25 or 3.46 differential. All these can be found from either an m coupe, or e28 and will bolt right in. I have a 3.46 from a e28 and it works great with my ZF trans. I think 3.73 is too aggressive for that transmission, the really short gears in a torquey car can fool you into thinking the car is slower than it is.

[japspecvr6]

i think a new diff will be my next Buy as well.....i think im gonna go wit the 3.23 or 3.25........

[bdi_fc]

Great responses. Thanks.

[bimmerboy570]

it would make sence more power you need more fuel to make it with