Thread: B14 ECU differences?

Of course there are differences between the 95-97 ECU and the 98-99 ECU, but does anyone know if there are any major differences between the '95 SE-R ECU and the '97 SE-R ECU?

All I know is ANY 95-98 ECU has a speed limiter which can be really annoying at certain tracks when it cuts out. You need a p10 ECU to eliminate that pesky bit of factory tuning.

So I have never heard of any ECU differences between 95-97 and 98 though. The only thing that changed in 98 as far as I know is the Transmission went to non-lsd, the cluster had color gauge faces PLUS the bubble tail lights of course (plus perhaps some other small trim changes)

Yeah I know of the exterior and trans differences. Just wondering if anyone knows for sure if there were any changes in the OEM ECU between 95 and 97.

You can cut the speed wire to the ECU


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Then you won't have a speedometer no?

Take a look at the FSM.... So the speed sensor in the trans is a AC Current generator and as it spins faster it has a higher frequency ... Check it with a DSO and you will see... In any case it goes to the cluster from the trans then the cluster converts the signal and it does down to the ECU ..... So in short .. Your speed on the dash works just fine... the ECU will not see the speed....

I build LOTS of ECUs (MegaSquirt) units and the MS2PNP that I build doesn't have a speed input to the ECU .. an engine doesn't need to know speed for any reason to run an engine... And the 100% everything works just fine on the cluster ..

Wow awesome! What's about the rev limiter? Is there a similar process?

Sorry, but that is just plain wrong. Speedometer input to ECU is utilized for a multitude of purposes. Other from the speed limiter, it can be used to raise the idle speed while rolling the car. This makes it easier to clutch in smoother, and the angular velocity difference wont make your clutch wear out prematurely.

Another use of the speed, is boost by gear. Here the car looks at speed/rpm, and estimates the gear used. This information is then used to raise/lower boost pressure, making wheelspin less likely on lower gears, and more power in higher gears where traction is of no concern.



No. You cannot cut the rpm-signal going into the ECU. That would make the car impossible to start, and all the fuel/ignition maps couldn't determine what range you are in.

A ghetto way to remove the revlimiter on CG engines, is to cover up the tiny 360deg slot inside the distributor. The car will still run fine, but it will crank longer due to missing this signal.

I think this would also apply to SR-engines, but why the heck anyone would do this mod is beyond my comprehension. A rev limiter is your friend, and a proper way to modify it, is to raise it with an upgraded ECU.

I think 98 is when they added the EVAP monitor. When I swapped a 98 engine into a 96 chassis i used the 96 ECU so that was one less monitor I had to worry about throwing a cel for Emissions testing. This was on a GA but I think that principle applies the same for the SR20 ecus.

Cool man thanks for the info. With a 97 ECU in my 98, I'm getting two codes: 10, 3 (park/neutral switch) and 7,7 (rear 02 sensor) which is expected since its not connected. The park neutral switch code may have something to do with my B14 having a B15 trans in it.