E30 top speed limiter

[nando]

So I've heard lots of arguments for and against the late model E30s having a top speed limiter in the past, and even argued against it myself a few times.

But now I have firsthand experience that there is indeed a speed limiter at 125mph - when my car was an auto it really wouldn't go much faster than 110 (and it took forever to get there too, no power) so I never got to test that theory. now it pulls hard all the way up to 125, and when it gets there it hits a really odd wall - almost like a rev limiter, but it doesn't bounce, it just holds steady. it's definitely not aerodynamics, I can physically feel the ECU cutting back the power (it's almost like I'm lifting off the throttle).

my car's build date is 10/90, and it left the factory as an auto - I know other E30s could go faster (135-140) and my car is nowhere close to being stock. it should be able to at least match a stock E30's top speed.

I'm curious as to what models/years have the speed limiter. if you've topped out your car past 125mph, post your build date, transmission and ECU model. I don't *really* care about high speed driving, but I was curious as to what my top speed was, and it would be nice to find a way to disable it and also know what cars have it.

also if anyone knows how the speed limiter might work, please share! I've been looking over wiring diagrams but they don't get very specific when it comes to the ECU. I have a chip (bavauto #500) but apparently that doesn't make a difference.

my info:
build date: 10/90
transmission: automatic (now a 5 speed)
ECU: #526 (325ix)

[PeaveyBassist]

1991 325i (dont know build date, car isnt here to check)
Trans: 5 spd manual
ECU: 173 I think

At 125mph it cuts and falls back to around 120, then you can go back to 125, but it will do the exact same thing.

Will

[blueapplesoda]

i ran out of gear (bounced rev limit) in 5th when i tried...i was going 115 about...but it was on a slight uphill......i didnt have time to wait until the down hill, since i was doing it on a freeway. only a small section where cops can't see you.

89 325is prod dat 1/89 original auto, 5spd swap.

[PeaveyBassist]

i ran out of gear (bounced rev limit) in 5th when i tried...i was going 115 about...but it was on a slight uphill......i didnt have time to wait until the down hill, since i was doing it on a freeway. only a small section where cops can't see you.

89 325is prod dat 1/89 original auto, 5spd swap.

Prolly because you have a 4.10 diff then :)

Will

[blueapplesoda]

yeee 4.10 ftw.

[pancake]

I've hit 125 in my 89 325i, but I don't remember it stopping me there. It could have been that I only hit 124 or something close though. I try not to do anything more than glance at my speedometer at that speed.

[AdamF 88iS]

I've done and indicated 130mph in a stock 325is.

[silverfbimmer]

built date 11/87
5spd

My car hit 133 and quit the same way every one elses did...It didn't bounce, it just would not let you accelerate anymore.

[nando]

Prolly because you have a 4.10 diff then :)

Will

huh? I have a 4.10 with the same tranny (getrag 260) and at 125 I'm at around 5800rpm. there is no way you could hit the rev limiter with a 4.10 in 5th gear.

[nando]

I've done and indicated 130mph in a stock 325is.

what build date (or year, at least)?

[AdironRider]

I saw similar things in my old stock 325is way back in the day, I figured it just ran out of power, but maybe I was wrong. I havent had my 318is over 110 though so I cant help you there.

[JasonC]

i hit 125 in my e down hill with 2.97 rear, don't remember it hitting limiter but i also let off the gas at 125 also. i'd try it now but i got a 3.73 lsd under it now so my top end has suffered.

[Brian 89 325i]

89 325i manual 3:73.
Build date 10/88
indicated 140 slight downhill

[AdamF 88iS]

what build date (or year, at least)?

10/87.

[wycoco]

I've done and indicated 130mph in a stock 325is.

Same. My 88 325iS. 5 speed.