Silver Label 506 vs. Red Label 413 ECU

[phreshkid]

Story goes like this:
I completed an obd1 m52 swap and I used the harness and all corresponding obd1 parts from a blown s50 that I bought for parts, including the silver label 506 ecu. I drive the car but something just doesn't feel right at all. It idles fine but the Check engine light stays constantly lit and I feel as if the motor isn't giving the power that it should be giving. I figured it might be the maf or the injectors or many other things but I never thought it was the ecu.

Today I go ahead and change from the 506 to the red label 413 from a 525i and I take it out for a spin. WHOLE NEW CAR. Power comes out of no where, torque comes out of everywhere, and it runs a whole lot smoother which is weird because I felt as if it was running smooth before. Oh and the Check engine light never comes on and stays off with the red label 413.

Now my question is this:

Could the silver label 506 ECU from the 95 s50 be a bad ECU or is it possibly not very applicable for the obd1 m52? I'm assuming that because the s50 has more litres, higher compression, and hotter cams, that maybe the stock ecu is programmed specifically for these s5o engine specs and when trying to run this ecu in a non-m motored car, it won't be able to fully open up and run at it's proper performance standard?

Can someone fill me in? Why was there such a significant change from the silver label 506 to the 413 red label? Why did the CEL go out with the 413 ecu?

Any ideas?

[Danny]

The only difference between the two is the chip. And yes the 506 is only for the 95 m3. Wrong tuning = shitty running swap.

[HakenTT]

Both ecus are the same exept for the chip. The 506 ecu will have the maps tuned for more camshaft duration. In order to test the 506 ecu, pull the chip out of 413 ecu and install it in 506 then test it again. Silver label indicates that ecu has a EWS chip in it

[phreshkid]

No my ecu is from an early s50 meaning I didn't have EWS and the motor runs just fine with it. EWS was never an issue. and the chip sounds about right. Another question: is the 506 silver label a better ecu than a red label 413 for an s52 swap given the chip's performance map?

[328ijunkie]

the M52 actually has a higher comp ratio ;)

[DTFE30]

Can I use the red label 413 in my 9/95 S50 swap?

[blackhawkimpact]

Yes, but you'll need a chip

[phreshkid]

You would actually be fine without a chip but again, 506 was made for the s50 while 413 was made for the m50. Two completely different motors, two completely different tunes. Stick with the 506 if you can. You're s50 will thank you.

[DTFE30]

So I am better off with a silver label 506? I purchased a red label 413 and i know i can get a chip that makes it work but would it still not be as good as a 506?

[phreshkid]

Well you'd want the proper chip for the corresponding motor it was produced for.

[DTFE30]

I am worried abt the ews. Will an after market chip in the red label get rid of the ews?

[CoClimber]

Red label doesn't have EWS. If you have an aftermarket chip for the red label, you still don't have EWS.

What I want to know is if there is a difference between running 506 or the silver label 413 with an AA chip that is set up for EWS delete, injectors, HFM, and headers (which my car has). What I mean is does the 506 make a difference or is my setup reasonably optimised.