OK. I'M GETTING HOOKED ON THIS SITE! HAS ANYONE OUT THERE TRIED WITH ANY SUCCESS TO CONVERT THE MECHANICAL FUEL INJECTION ON THE 6.3 TO THE ELECTRONIC SYSTEM USED ON THE 3.5 LITER (4.5 STATESIDE).ANY OTHER SUGGESTIONS WELCOME.
PETER.

No, the EFI on these older models was junk. It was hard to tune and not reliable. I would consider doing a modern efi though. There are many companies that are making kits for stand alone EFI.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I agree with Benzmac. The old systems were problematic and the difference in displacement would be difficult to overcome. I've had good result with Electromotives Systems. Although this will require lots of R&D the end result could be a car that out performs the original. The original mechanical injection on the 6.3s was full of compremises. One other logical replacement would be to adapt K'jet from a late 70s 6.9. Its sounds like fun to me!

I had considered an EFI conversion on my own 6.3. But after some serious research I didn't think $4000 in hardware(and software)would improve things very much. Just think what it would cost to duplicate the high-pressure mechanical injection system that the car came with...
It hard to improve on the system it's got.Most of the aftermarket EFI systems are meant to be an improvement over carburators.
Randy D.

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W.R.Durrance
ASE Master Tech
Mercedes Tech 20 Years
68 250SE
68 SAAB 96 Ice Racer
69 300SEL 6.3
70 300SEL 3.5
81 300TDT

I believe that Karl Middelhauve has done the KHM electronic injection on a couple of 6.3s. Read the latest issue of the Star magazine and the article about his 300SE 6.3 coupe should be in there. It describes the fuelie system. I guess it's his own brainchild.


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'72 Alfa Romeo 2000GTV
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12

quote:

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Originally posted by Aaron:


I believe that Karl Middelhauve has done the KHM electronic injection on a couple of 6.3s. Read the latest issue of the Star magazine and the article about his 300SE 6.3 coupe should be in there. It describes the fuelie system. I guess it's his own brainchild.

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I saw the 300SE Coupe/6.3 conversion last summer at the M-100 Group meeting.I talked with the guy that did the developement work (Dale). The system is based on a kit made for American V8s(that's what Dale usually works on).It uses a manifold pressure sensor, cam and crank position sensors,temp sensors, and an O2 sensor.
One of the odd things was the intake manifold. Its an air box with very short runners. The installer thought that the tuned runners in the original were only for low rpm torque...actually the intake runner length is for mid-range power. The modified intake is supposed to improve high rpm operation. But a 6.3 suffers from excessive piston speed (over 3800 fpm) at around 6100 rpm. Not a candidate for "high rpm" operation. At $10,000 the system isn't cheap. For that kind of money, I would want at least a 50% increase in power(with dyno sheets). The mileage figures were less than impressive (9.6 mpg city;15.7 mpg hiway). So far, there are no dynamometer numbers I know of(though the article does claim 435 HP). Any output increase may be due to the 10.5:1 compression pistons (Star Motors) and the sport cams(developed jointly by Star Motors and W.R.Durrance Engineering)
Its still hard to beat mechanical injection in good working condition.
Randy D.


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W.R.Durrance
ASE Master Tech
Mercedes Tech 20 Years
68 250SE
68 SAAB 96 Ice Racer
69 300SEL 6.3
70 300SEL 3.5
81 300TDT