m3 swap turbo/supercharger question

NyteRyda · #1 (**permalink**) 04-09-2005, 12:37 PM

I know this probably been asked a million times but o what the hell. I am planning to get an m3 engine swap for my 325is in the future. I heard that dropping a 95 m3 engine in would be the best fit? Is that true? Would it be easier to fit the 95 engine then a 96 and up 3.2 engine? and why? Also if I was to put in a 3.2 m3 engine how would it be possible to convert it back to obd1? Also what other parts would I need beside the engine? Also what good companys of turbo chargers or super chargers are good for an m3 engine? OR would it be cheaper to buy a used 95 m3 and add a turbo/ supercharger to it?

SwolenColen · #2 (**permalink**) 04-09-2005, 02:55 PM

I think an engine swap would be a waste of money if you're planning on turbo - just get dished pistons and drop ur CR to 8 - 8.5, and put like 15 lbs of boost into it... that should bring you to like 320 hp. engine swaps are a lot of money and work, and you'd have to prepare the m3 engine anyway, and you'd only get 30 hp out of the whole deal.

NyteRyda · #3 (**permalink**) 04-09-2005, 10:12 PM

how much would dished pistons cost and what brands should I look into? Also what do you mean by dropping my CR??

amat3ur · #4 (**permalink**) 04-10-2005, 10:50 AM

If you are asking what CR means it stands for compression ratio. And you want to lower your compression ratio if you are going to turbo your engine.

NyteRyda · #5 (**permalink**) 04-10-2005, 06:57 PM

thanks for the help amat3ur. I need to learn a lot more about turbo or super chargers. Also what is needed to lower the compression ratio? Also what forged piston brands and brands of turbo or superchargers would best suit my car?

queenz · #6 (**permalink**) 04-10-2005, 07:05 PM

Quote:

Originally Posted by NyteRyda

I know this probably been asked a million times but o what the hell. I am planning to get an m3 engine swap for my 325is in the future. I heard that dropping a 95 m3 engine in would be the best fit? Is that true? Would it be easier to fit the 95 engine then a 96 and up 3.2 engine? and why? Also if I was to put in a 3.2 m3 engine how would it be possible to convert it back to obd1? Also what other parts would I need beside the engine? Also what good companys of turbo chargers or super chargers are good for an m3 engine? OR would it be cheaper to buy a used 95 m3 and add a turbo/ supercharger to it?

My 92 325is has a 3.2L in her now.. As for the OBD1 since a 92 is dosen
t have all the sens like a 96 and up car.. the setup was perfect..

queenz · #7 (**permalink**) 04-10-2005, 07:10 PM

Quote:

Originally Posted by NyteRyda

thanks for the help amat3ur. I need to learn a lot more about turbo or super chargers. Also what is needed to lower the compression ratio? Also what forged piston brands and brands of turbo or superchargers would best suit my car?

Year do your homework.. i plan on turbo for my car. If u want high boost u must work the engine and lower the CR

SwolenColen · #8 (**permalink**) 04-11-2005, 02:40 PM

compression ratio is how much ur engine squishes the air and fuel in the cylinder before ignition - the lower the compression, the more boost you can put into it without any detonation, which is explosion before ignition, and is not good. The dished pisons just have a cavity in them that makes it squish less stuff, because some escapes into the dish. Ireland Engineering has custom pistons for $850, and JE also makes good pistons. I am getting the Ireland Engineering pistons this month, but I haven't heard nething on their reliability or quality. Also don't get a kit, build the system yourself. Get Maximum Boost by Corky Bell - its a little old and behind the times, and sometimes hes not very specific, but it has a lot of good information that you should know before putting a turbo in.

amat3ur · #9 (**permalink**) 04-12-2005, 10:45 AM

I believe, correct me if I am wrong, that a few ways to lower the CR is to get a low compression head gasket and pistons. Does anyone know how much that will lower it.

Josh · #10 (**permalink**) 04-12-2005, 12:26 PM

The S52 will drop right in, no problem. Because that engine was meant for OBD2, you will need to do a little extra work with the sensors and a few other parts to make it OBD1 compatible. This would not be a big deal for a shop that knows what they are doing and a lot of your M50 parts can be used to aid in the conversion, like the intake manifold.
Do the engine swap first and then determin what power route you want to go. It is a much better platform to start from. Don't bother with building up your 2.5, as it is not very cost effective depending on how much power you are realistically looking for. Well over 400 rwhp can be had safely on a S52 with stock internals.

SwolenColen · #11 (**permalink**) 04-12-2005, 02:04 PM

if you get a thicker headgasket, it will lower compression, but thats the ghetto way of doing it. Pistons are the way to go, and you can drop it however much you want - the thicker the headgasket / bigger dish in the piston, the lower the CR will be.

SwolenColen · #12 (**permalink**) 04-12-2005, 02:07 PM

Quote:

Originally Posted by Josh

The S52 will drop right in, no problem. Because that engine was meant for OBD2, you will need to do a little extra work with the sensors and a few other parts to make it OBD1 compatible. This would not be a big deal for a shop that knows what they are doing and a lot of your M50 parts can be used to aid in the conversion, like the intake manifold.
Do the engine swap first and then determin what power route you want to go. It is a much better platform to start from. Don't bother with building up your 2.5, as it is not very cost effective depending on how much power you are realistically looking for. Well over 400 rwhp can be had safely on a S52 with stock internals.

with the money you spend on an engine swap, you can completely prepare your current engine and boost the hell out of it... you setup the engine right and you can run 15 psi eeeeeasily. theoretically 14.7 psi should double the stock horse (168 --> 336), so 15psi should definately give you at least 300, which would be difficult to get w/ an engine swap, unless you went w/ like a 4.0 V8

Josh · #13 (**permalink**) 04-12-2005, 02:09 PM

Quote:

Originally Posted by SwolenColen

if you get a thicker headgasket, it will lower compression, but thats the ghetto way of doing it. Pistons are the way to go, and you can drop it however much you want - the thicker the headgasket / bigger dish in the piston, the lower the CR will be.

I fail to see what is "ghetto" about a perfectly safe and proven method of lowering compression.

Josh · #14 (**permalink**) 04-12-2005, 02:11 PM

Quote:

Originally Posted by SwolenColen

with the money you spend on an engine swap, you can completely prepare your current engine and boost the hell out of it... you setup the engine right and you can run 15 psi eeeeeasily. theoretically 14.7 psi should double the stock horse (168 --> 336), so 15psi should definately give you at least 300, which would be difficult to get w/ an engine swap, unless you went w/ like a 4.0 V8

Right and you have a smaller engine capable of less power and nothing to build off of if he wants to raise the bar on his setup.

SwolenColen · #15 (**permalink**) 04-12-2005, 02:28 PM

how much power do you want? Turbo will get you to 350 w/o going nuts on your engine if you do it right. You can drop in nitrous if you want, but going with the 3.0 or 3.2 will only give you 50 hp max, not to mention costing tons of money. If you have all the money in the world, and don't care about details of handling / weight distribution, then there is no reason to stay with a 2.5 liter engine, but if you dont have a money tree in your front yard i would not suggest a swap.