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Smallblock454 · 10-24-2016, 01:29 PM

Hello Carlos,

if your car is an AT car, it's easier to use an AT engine, because if you buy an MT engine some things have to be replaced and transferred from the AT to the MT engine. But it's no rocket science.

If you're talking about 2003 i don't know if it's a 252 or a 260 HP engine.

Over here in Germany the 2003 986S cars had the 260 HP engine.

The 2003 / 2004 engines (228 / 260 HP / 266 HP) have a much better adjustment system for the camshafts that works without chain ramps. I would prefer these engines in general.

The later engines from 987 cars won't fit without ECU and other adaptions. What can fit is an engine from a 987S 280 3.2 car. But these are rare and were only built in 2005 (think it's the 2006 US model).

The later on 987 3.4 engines have a different IMSB that can't be changed without disassembling the engine.

AT engines can't be overreved that easy, because the AT electronic prevents that. MT engines can be overreved easily. Overreving can cause problems. Maybe that is why the workshop has asked for an AT engine.

In general all types of M96 986 engines can be used, but if you don't use exactly the same engine type you have to adapt wiring harness, ECU and / or ECU / TCU software… Emissions can also be a problem.

Easiest to install is to use the exact same engine that was used in your car.

Because the engine is toast, just think of other options like B4, V6 or V8 engines. OK, maybe this is not the easy way, but to me personally this would be a nice challenge. Over here in Germany it's very very complicated to do these kind of conversions because of law regulations. But in the US it seems to be much easier to get it street legal.

Regards, Markus

10-24-2016, 01:29 PM	#3
Smallblock454 Registered User Join Date: Jun 2014 Location: LB, Germany Posts: 1,456	Hello Carlos, if your car is an AT car, it's easier to use an AT engine, because if you buy an MT engine some things have to be replaced and transferred from the AT to the MT engine. But it's no rocket science. If you're talking about 2003 i don't know if it's a 252 or a 260 HP engine. Over here in Germany the 2003 986S cars had the 260 HP engine. The 2003 / 2004 engines (228 / 260 HP / 266 HP) have a much better adjustment system for the camshafts that works without chain ramps. I would prefer these engines in general. The later engines from 987 cars won't fit without ECU and other adaptions. What can fit is an engine from a 987S 280 3.2 car. But these are rare and were only built in 2005 (think it's the 2006 US model). The later on 987 3.4 engines have a different IMSB that can't be changed without disassembling the engine. AT engines can't be overreved that easy, because the AT electronic prevents that. MT engines can be overreved easily. Overreving can cause problems. Maybe that is why the workshop has asked for an AT engine. In general all types of M96 986 engines can be used, but if you don't use exactly the same engine type you have to adapt wiring harness, ECU and / or ECU / TCU software… Emissions can also be a problem. Easiest to install is to use the exact same engine that was used in your car. Because the engine is toast, just think of other options like B4, V6 or V8 engines. OK, maybe this is not the easy way, but to me personally this would be a nice challenge. Over here in Germany it's very very complicated to do these kind of conversions because of law regulations. But in the US it seems to be much easier to get it street legal. Regards, Markus Last edited by Smallblock454; 10-24-2016 at 05:34 PM.