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does anyone have experience with or know of a supplier or modification to limit the 91 e34 motor to say 5000 rpm? ie- a valet switch? thanks.
 

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djk:

Although I am completely unaware of anything that would drop the E34 M5’s rev-limiter as you mention, I must comment on your asking such a unique question. This when we always see the same top 10-20 questions about these cars quite literally get beat to death over and over again each time someone new becomes a new m5board member or happens to buy an E34 M5. I wish Gustav gave out an award for things exactly like this, as I’d also guess Paul DeWitt would just happen to agree with as well.

Your reasoning is obvious based on your referring to this as a form of a valet switch. It would also be quite handy when anyone else was driving your M5, such the kid’s (for those with families) that always seem to say they will drive very slow when you obviously know that won’t be the case anyway.

Prior to buying the two M5’s, I was driving one of those American sports cars with a 350 cu. in. V8 and a single rather large throttle body rather than one per cylinder. One day while at lunch I valet’s the car since my time was limited. After lunch, the kid runs off to get the car. All of a sudden there is this familiar sound of a very throaty Flowmaster exhaust and melting tires. I remain calm as the kid comes back with the car and mention that he can go scrape his tip up since he left at least $20-40 of rubber in the parking lot on his way back with the car. Not to mention he got to drive with the top down on a beautiful day. I considered the attempt to teach him a lesson far outweighed making a scene when I did much worse things in the car myself on a regular basis anyway.

In a situation like that there are two benefits to having such a dramatic rev-limiter on a car. One is the obvious and the second would be seeing the absolutely priceless look on a valet’s face as he puts his foot to the floor and only realizes partial throttle response. That alone would be worth having for the comedy factor alone.

Although I can not recall seeing this question having been asked anywhere in my roughly six years of participating on numerous E34 M5 boards and forums, this would have obviously been on a few minds already at least. Perhaps someone does have some form of a solution for you.

Although it’s been a number of years since I’ve spoken to him, Andy Cohen owned Beverly Hills Motoring Products, if anyone had something that performed in this manner or even knew that it existed, it would be him. He would either have it himself, or at least be able to point you in the right direction. A quick yahoo or google search will get you their phone number or e-mail address for inquiries. It’s been roughly 10 years since I either saw Andy or spoke with him on the phone. However, I’m sure he’s still running the business, as I have not heard otherwise. Good luck with this unique request.

Its by far the most interesting and or unique question that I’ve seen asked in my six years or so that I’ve been participating in these types of dialogs. It’s honestly also quite refreshing to see in my opinion.

Regards,

Ken Little
 

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I have a product in my scooter-tune shop that does what you want.
It is intended (obviously) for scooters, and the function is that if a rider should be stopped by police, for riding his scooter too fast, he can activate this revlimiter by activating the brakelight 3 times, in a preset "code" (ex: long-long-short).
In a car one would connect it to a switch, not the brakelights :)
When the revlimiter is activated, it simply cuts off engine rpm at the preset level. So that when the policeofficer wants to rev the scooters engine in order to guess if it has been tuned (wich is illegal here), it will not sound like a highreving tuned engine.
And, it will not go too fast if the officer wants to take it for a testdrive.

I see no problem at all in connecting it on the S38B36 engine.

Allthough i dont know the range adjustment, im pretty sure it covers something like 2k rpm - 20k rpm (on a 2-stroke).

I dont know wich company makes it, as it is completely un-marked, and i get it from a tune-parts distributor in Germany.

It is cheap.. 50,- Eur. retail.

If you cant find anything else, maybe there is some scooter-tune shop in LA. that have something similar?

PS. I once had an alarmsystem intended for scooters installed in the M5, worked allmost perfectly, and had more functions than most car-alarms, and the retail price on that is ~100,- Eur.. way below any car-alarm.
Only problem was the remote enginestart function, it was designed so that the user should press a button on the remote and hold it to crank the engine, once it fired the user should ofcourse release the button, but.. when the button was released, the starter motor would stay on for 1-2 sec's ekstra.. not the nicest sound! This is why i disconnected it.
Driving around without having the keys with me, was quite fun for a couple of days though :)

PPS. Now you made me i wanna install a revlimiter.. if nothing else, just to have another gadget to play with :)
 

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As far as I can remember you can buy simple limiters which sit across the two coil terminals. They 'learn' a rev limit by holding the engine at the desired speed then pressing a set button. When the engine reaches this speed it shorts the -ve side to earth or switches the coil off completely! All it does is monitor coil switching rates. Not at all subtle but effective.

Of course this will not work with the S38's 6 individual coil packs!!

Why not fit Racelogic traction control. I'm certain they could adapt it to your needs...........

Racelogic
 

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djk:

Although I am completely unaware of anything that would drop the E34 M5’s rev-limiter as you mention, I must comment on your asking such a unique question. This when we always see the same top 10-20 questions about these cars quite literally get beat to death over and over again each time someone new becomes a new m5board member or happens to buy an E34 M5. I wish Gustav gave out an award for things exactly like this, as I’d also guess Paul DeWitt would just happen to agree with as well.

Your reasoning is obvious based on your referring to this as a form of a valet switch. It would also be quite handy when anyone else was driving your M5, such the kid’s (for those with families) that always seem to say they will drive very slow when you obviously know that won’t be the case anyway.

Prior to buying the two M5’s, I was driving one of those American sports cars with a 350 cu. in. V8 and a single rather large throttle body rather than one per cylinder. One day while at lunch I valet’s the car since my time was limited. After lunch, the kid runs off to get the car. All of a sudden there is this familiar sound of a very throaty Flowmaster exhaust and melting tires. I remain calm as the kid comes back with the car and mention that he can go scrape his tip up since he left at least $20-40 of rubber in the parking lot on his way back with the car. Not to mention he got to drive with the top down on a beautiful day. I considered the attempt to teach him a lesson far outweighed making a scene when I did much worse things in the car myself on a regular basis anyway.

In a situation like that there are two benefits to having such a dramatic rev-limiter on a car. One is the obvious and the second would be seeing the absolutely priceless look on a valet’s face as he puts his foot to the floor and only realizes partial throttle response. That alone would be worth having for the comedy factor alone.

Although I can not recall seeing this question having been asked anywhere in my roughly six years of participating on numerous E34 M5 boards and forums, this would have obviously been on a few minds already at least. Perhaps someone does have some form of a solution for you.

Although it’s been a number of years since I’ve spoken to him, Andy Cohen owned Beverly Hills Motoring Products, if anyone had something that performed in this manner or even knew that it existed, it would be him. He would either have it himself, or at least be able to point you in the right direction. A quick yahoo or google search will get you their phone number or e-mail address for inquiries. It’s been roughly 10 years since I either saw Andy or spoke with him on the phone. However, I’m sure he’s still running the business, as I have not heard otherwise. Good luck with this unique request.

Its by far the most interesting and or unique question that I’ve seen asked in my six years or so that I’ve been participating in these types of dialogs. It’s honestly also quite refreshing to see in my opinion.

Regards,

Ken Little
Hey Ken, sorry for the late response and thank you for the kind words about Andy! He was an expert in this field and had a lot of insights to offer in the industry. He passed away in late 2019, but he passed on his expertise to his son Kevin. To this day his accessory company is still up and running online at: Beverly Hills Motoring. If you guys have any questions feel free to email us at: [email protected]
 
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