a while back, a number of posts indicated the difficulty, in not impossibility, of removing the rev-limiter on the 16v solely through reprogramming of the ECU (there were also some less than positive remarks concerning quickchips, itself). about 2 years ago, i sent my ECU to quickchips for reprogramming. i did not have the car dyno-tested before and after, but know of at least one who did, and found that the hp increased advertised by quickships (18hp for a 16v) was obtained through the reprogamming and verified by the dyno-testing. i am also satisfied with a performance difference in my own car.

after seeing the postings, i did worry that maybe the rev-limiter had not been removed, as had been claimed. i am releived to report that an evening or so ago, my tachometer revved above 7000 rpm with no cut-out or apparent limit. i didn't stay above 7000rpm for too long (don't want to blow up my engine), but i am satisifed, unless my tachometer is defective, that the quickchips reprogramming sucessfully removed my rev-limiter.

the quickchips guys may not be too free with information or be particulary warm and fuzzy, but i think that their product (at least for the 16v) performs as advertised.

FYI,

John

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john
'77 6.9
'87 2.3-16v
'92 500E

The rev limiter is built into the fuel pump relay & receives info for engine speed from the ignition control unit. I rev my 8V 2.3 to 7400, but the power is done at 6900.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR

perhaps you could answer a couple of questions (mostly showing my lack of understanding of how engines work) regarding you response:

isn't the purpose of a rev limiter to limit revs? if an engine continues to rev past a rev limit, is there actually a rev limit?

how does the engine gain the power necessary to exceed the rev limit? does it need additional fuel to power the additional revs? if the rev limiter were built into the fuel system, wouldn't it cut out fuel to reduce the revs?

by comparison, the rev limiter on the 500E truly limits revs: hit the limit, and the fuel cuts out to slow the engine below the rev limit. as far as i can tell, the car positively cannot be revved above the limit. does this work differently somehow for the 16v? is this a terminology problem? is the "rev" limiter for the 16v not really a rev limiter but an "output" limiter of some sort? accomplished by somehow altering the power output of the engine (fuel mixture? timing?) But then again, why reduce the output without limiting revs since i presumed that purpose to limiting the revs was two-fold: 1) limit speed and 2) limit revs in order not to damage the engine.

when you rev to 7400, is this continuous, or just an "overreaching" or a lag to actuation of the limiter? if your power is over at 6900, do you mean that the engine reaches its natual peak (i.e., the top of the torque or horsepower curve) at 6900 rpm, or do expect that peak is past 6900rpm?

thanks in advance for clarifications:

John




[This message has been edited by revbond (edited 09-20-1999).]

I would like to know more about quickchips, how to contact them, about the company, how much did it cost to set the rev limiter at a higher level and any other information about this topic would be appreciated.

thank you
Mauro G.
87 190e 16v

With CIS-E fuel systems the fuel pump cut-out controls the rev's. On my race car the fuel pump relay has been removed, so no rev limit. Also at full throttle the computer doesn't control the fuel mixture like it does at cruise. On the 16V engines some slight resistance value changes can pick-up some hp. The ignition system is where most "chip" tuners gain power & this would be very tricky on the EZL that M.B. uses

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR

located in huntington beach, CA; phone: 714-270-6388 (ask for scott). the modification cost $400 two or three years ago.

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john
'77 6.9
'87 2.3-16v
'92 500E

[This message has been edited by revbond (edited 09-30-1999).]