Option Code M251 ??
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From: Double Oak, TX
Be a blast, but I wonder what the revs would be at 80 mph?
Should have kept the 89 5speed!
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
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From: Helsinki, Finland
Just to clarify. Low compression pistons for M21/22 was option M151. Its possible C09 and C10 cars had that engine without having option listed if it was standard based on country code.
There is separate part number for M151 piston. Actully six of them.
Some '85 MY C23 had it with code on option list while others didn't which can mean they had normal 10.4:1 CR engine. '86 MY C23 used low compression M45/46 which obviously had code M298 and M299 in those countries where that engine and cat converter was optional.
M251 gearbox is totally separate thing and is not directly linked to car having M151 engine even though some '86 MY cars had them both. Either as part of the country specific spec as as an option.
There is separate part number for M151 piston. Actully six of them.
Some '85 MY C23 had it with code on option list while others didn't which can mean they had normal 10.4:1 CR engine. '86 MY C23 used low compression M45/46 which obviously had code M298 and M299 in those countries where that engine and cat converter was optional.
M251 gearbox is totally separate thing and is not directly linked to car having M151 engine even though some '86 MY cars had them both. Either as part of the country specific spec as as an option.
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From: Anaheim
Just to clarify. Low compression pistons for M21/22 was option M151. Its possible C09 and C10 cars had that engine without having option listed if it was standard based on country code.
There is separate part number for M151 piston. Actully six of them.
Some '85 MY C23 had it with code on option list while others didn't which can mean they had normal 10.4:1 CR engine. '86 MY C23 used low compression M45/46 which obviously had code M298 and M299 in those countries where that engine and cat converter was optional.
M251 gearbox is totally separate thing and is not directly linked to car having M151 engine even though some '86 MY cars had them both. Either as part of the country specific spec as as an option.
There is separate part number for M151 piston. Actully six of them.
Some '85 MY C23 had it with code on option list while others didn't which can mean they had normal 10.4:1 CR engine. '86 MY C23 used low compression M45/46 which obviously had code M298 and M299 in those countries where that engine and cat converter was optional.
M251 gearbox is totally separate thing and is not directly linked to car having M151 engine even though some '86 MY cars had them both. Either as part of the country specific spec as as an option.
The M251 option was a still shorter ratio for mountain road use (2.54)......and for someone that really wants a very "quick" vehicle.
Both the European and the "mountain use" transmission also came with a higher stall torque convertor....to allow the engines to get into the power range quicker. With the higher compression engines, these cars should perform quite well.
I still have a couple of these transmissions, brand new, in the factory boxes. (Both European ratio and the M251 option.)