Speed Limiter
MBWorld Fanatic!
Joined: May 2007
Posts: 1,450
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From: British Columbia, Canada
1987 560SL
Look for an aftermarket chip - often sold on eBay
They don't do much more than just move the shift points around, but often a speed-limiter removal feature is included, too.
They don't do much more than just move the shift points around, but often a speed-limiter removal feature is included, too.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 1,016
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Not much. I always wonder why people bother.
Unless you've done the C36 swap or turboed/ supercharged your car, you're really only chasing what, 6- 10 extra on the top end.
I did a power limited ~130 in my 2.6 on a really long down hill once. The second you level off speed drops off and if you start climbing it drops off quickly.
The E320 gets up there relatively easily, but struggles to gain appreciably beyond 130, then hits the limiter. I think I did 140. My tires are slightly larger than stock.
Aero starts to really dampen acceleration at about 130- 140. You need real power to keep accelerating much beyond that. 217 won't cut it.
Unless you've done the C36 swap or turboed/ supercharged your car, you're really only chasing what, 6- 10 extra on the top end.
I did a power limited ~130 in my 2.6 on a really long down hill once. The second you level off speed drops off and if you start climbing it drops off quickly.
The E320 gets up there relatively easily, but struggles to gain appreciably beyond 130, then hits the limiter. I think I did 140. My tires are slightly larger than stock.
Aero starts to really dampen acceleration at about 130- 140. You need real power to keep accelerating much beyond that. 217 won't cut it.
Thread Starter
Junior Member
Joined: Apr 2010
Posts: 74
Likes: 0
From: Des Plaines, IL
1995 E320
Im going to be running hr touring suspension, ceginus evo 2 wheels on continental tires, along witn some small things like k&n drop in and center muffler delete and a mild brake upgrade. Im not expecting it to be a race car or anything just a drivers car. I baby it and only has 65k miles. I love this car. My old 95 E320 had a goofy ecu and it didn't rev limit or speed limit and i got it over 150mph. Im not gonna go that fast ever if so once or twice but it bothers me that the limiter is there for some reason. Its my favorite car. I fell in love with the w124 when i bought my first mercedes which was a 87 300e. Yeah the 500e is the one everybody want but i love the inline 6. Still think Mercedes screwed up by getting rid of the setup. Any input on where i can get quality chip is a plus. I don't drive car daily so sending ecu out don't bother me
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
tec_nine -
I don't think you are going to find a true performance "chip" solution a la modified firmware because our ECUs do not have socketed or flash programmable EEPROMs in them. Thus, any true firmware solution will require the ECU be sent to a shop for such an update (unless, of course, you happen to have a full SMD soldering/desoldering workstation and programmer). The "performance" kits that I have seen just modify the signals to the ECU via external hardware. Usually they play will Intake Air Temp or the O2 sensors signals to fake the ECU into richening up the mixture. I would suspect they are of dubious benefit and most certainly would not address the speed limiter.
I took a quick look at the schematic for our cars (we both have '95s which are equipped with electronic throttle control) and the speed limit is actually accomplished via the EA/Cruise module and not the ECU directly. So new ECU firmware wouldn't help if you could even find it. The EA/CC module takes its speed signal from the Hall Effect speed sensor on the speed-o-cluster. In theory, the speed signal could be manipulated here, but outright disconnection would kill the cruise control and screw up the ABS system if you have ASR. It would certainly be possible to make an inline module that took the Hall Effect sensor input and when the speed exceeded some value - say 120 MPH - outputs a constant 120 MPH signal. Thus, the EA/CC module would never know how fast you are really going, but all the ancillary functions would still function properly (Would you really set cruise over 120? At that speed, if you need ABS, you're toast anyway).
But is it really worth it? Doesn't seem like it to me.
BTW, if you still want to play with performance firmware, word has it that this company ECU Technologies can transplant the E36 firmware into your ECU, just break out your wallet for this and a 95 C36 engine.
I don't think you are going to find a true performance "chip" solution a la modified firmware because our ECUs do not have socketed or flash programmable EEPROMs in them. Thus, any true firmware solution will require the ECU be sent to a shop for such an update (unless, of course, you happen to have a full SMD soldering/desoldering workstation and programmer). The "performance" kits that I have seen just modify the signals to the ECU via external hardware. Usually they play will Intake Air Temp or the O2 sensors signals to fake the ECU into richening up the mixture. I would suspect they are of dubious benefit and most certainly would not address the speed limiter.
I took a quick look at the schematic for our cars (we both have '95s which are equipped with electronic throttle control) and the speed limit is actually accomplished via the EA/Cruise module and not the ECU directly. So new ECU firmware wouldn't help if you could even find it. The EA/CC module takes its speed signal from the Hall Effect speed sensor on the speed-o-cluster. In theory, the speed signal could be manipulated here, but outright disconnection would kill the cruise control and screw up the ABS system if you have ASR. It would certainly be possible to make an inline module that took the Hall Effect sensor input and when the speed exceeded some value - say 120 MPH - outputs a constant 120 MPH signal. Thus, the EA/CC module would never know how fast you are really going, but all the ancillary functions would still function properly (Would you really set cruise over 120? At that speed, if you need ABS, you're toast anyway).
But is it really worth it? Doesn't seem like it to me.
BTW, if you still want to play with performance firmware, word has it that this company ECU Technologies can transplant the E36 firmware into your ECU, just break out your wallet for this and a 95 C36 engine.
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Thread Starter
Junior Member
Joined: Apr 2010
Posts: 74
Likes: 0
From: Des Plaines, IL
1995 E320
tec_nine -
I don't think you are going to find a true performance "chip" solution a la modified firmware because our ECUs do not have socketed or flash programmable EEPROMs in them. Thus, any true firmware solution will require the ECU be sent to a shop for such an update (unless, of course, you happen to have a full SMD soldering/desoldering workstation and programmer). The "performance" kits that I have seen just modify the signals to the ECU via external hardware. Usually they play will Intake Air Temp or the O2 sensors signals to fake the ECU into richening up the mixture. I would suspect they are of dubious benefit and most certainly would not address the speed limiter.
I took a quick look at the schematic for our cars (we both have '95s which are equipped with electronic throttle control) and the speed limit is actually accomplished via the EA/Cruise module and not the ECU directly. So new ECU firmware wouldn't help if you could even find it. The EA/CC module takes its speed signal from the Hall Effect speed sensor on the speed-o-cluster. In theory, the speed signal could be manipulated here, but outright disconnection would kill the cruise control and screw up the ABS system if you have ASR. It would certainly be possible to make an inline module that took the Hall Effect sensor input and when the speed exceeded some value - say 120 MPH - outputs a constant 120 MPH signal. Thus, the EA/CC module would never know how fast you are really going, but all the ancillary functions would still function properly (Would you really set cruise over 120? At that speed, if you need ABS, you're toast anyway).
But is it really worth it? Doesn't seem like it to me.
BTW, if you still want to play with performance firmware, word has it that this company ECU Technologies can transplant the E36 firmware into your ECU, just break out your wallet for this and a 95 C36 engine.
I don't think you are going to find a true performance "chip" solution a la modified firmware because our ECUs do not have socketed or flash programmable EEPROMs in them. Thus, any true firmware solution will require the ECU be sent to a shop for such an update (unless, of course, you happen to have a full SMD soldering/desoldering workstation and programmer). The "performance" kits that I have seen just modify the signals to the ECU via external hardware. Usually they play will Intake Air Temp or the O2 sensors signals to fake the ECU into richening up the mixture. I would suspect they are of dubious benefit and most certainly would not address the speed limiter.
I took a quick look at the schematic for our cars (we both have '95s which are equipped with electronic throttle control) and the speed limit is actually accomplished via the EA/Cruise module and not the ECU directly. So new ECU firmware wouldn't help if you could even find it. The EA/CC module takes its speed signal from the Hall Effect speed sensor on the speed-o-cluster. In theory, the speed signal could be manipulated here, but outright disconnection would kill the cruise control and screw up the ABS system if you have ASR. It would certainly be possible to make an inline module that took the Hall Effect sensor input and when the speed exceeded some value - say 120 MPH - outputs a constant 120 MPH signal. Thus, the EA/CC module would never know how fast you are really going, but all the ancillary functions would still function properly (Would you really set cruise over 120? At that speed, if you need ABS, you're toast anyway).
But is it really worth it? Doesn't seem like it to me.
BTW, if you still want to play with performance firmware, word has it that this company ECU Technologies can transplant the E36 firmware into your ECU, just break out your wallet for this and a 95 C36 engine.
