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///M325i
12-07-2010, 01:04 PM
Hi, i have a 1994 BMW 325i and i would like to rebuild the engine on it. After the rebuild is done i would like to turbo the engine. I wanted to know if this is even worth it, my engine has 250xxxkm and that's a lot. All i'm looking for is MORE power and better performance!! So my question is: Is it worth rebuilding an old 1994 m50 with 250xxxkm on it then shortly after turbochargeing it? And would the give me the power and better performance i'm looking for??

hockeyfan27
12-07-2010, 01:27 PM
When researching whether or not I was going to buy my car -it was high KM and I was a bit apprehensive - I read that some race team somewhere would look for BMW blocks to rebuild into race engines in the scarp yard. They felt it was better stress tested then a new block would be and was a better starting point.

craz azn
12-07-2010, 07:47 PM
Not worth it at all.

Dissembler
12-07-2010, 08:23 PM
Find an M52 and build that for boost. Collect all the parts you'll need (exhaust pieces, intercooler, lines etc etc) and then that way you will still have a DD, and when everything is ready, drop the new motor in over a weekend.

Or V8 swap http://images.bimmerforums.com/smilies/devillook.gif

dble Trouble
12-08-2010, 12:00 AM
When researching whether or not I was going to buy my car -it was high KM and I was a bit apprehensive - I read that some race team somewhere would look for BMW blocks to rebuild into race engines in the scarp yard. They felt it was better stress tested then a new block would be and was a better starting point.

That was BMW in the early '80's and they didn't go to the scrap yard, they were specifically looking for cars that had dd'd for 40,000km and use that block, anything more than that they felt might have been TOO stressed, that was in the heavy turbo charging days when they were making 1200 hp!

///M325i
12-08-2010, 11:01 AM
Find an M52 and build that for boost. Collect all the parts you'll need (exhaust pieces, intercooler, lines etc etc) and then that way you will still have a DD, and when everything is ready, drop the new motor in over a weekend.

Or V8 swap http://images.bimmerforums.com/smilies/devillook.gif


yeah ehh, you think a 328 motor will be better off turbocharged then a 325i? Well i fully agree with you but the thing is i dont want to swap out the motor, that's too much work plus if i was going to swap out the motor i would swap it for the s52 3.2L that was the original plan but things kept coming up. So i just settled for the quick engine rebuild and the forced induction to get that sweet power :cool: But thats not a bad concept you've given me get all the part together then throw em in over the weekend. Also have another question whats "DD"?

///M325i
12-08-2010, 11:06 AM
Not worth it at all.

Really? Why do you say that? And do you have an alternative to getting more power out of an old 94 325i if the engine rebuild and forced induction wouldn't be worth it?? All i'm looking is more power/performance.

///M325i
12-08-2010, 11:21 AM
ok just found out what DD mean sorry lol it mean daily driver lol

craz azn
12-08-2010, 12:06 PM
Really? Why do you say that? And do you have an alternative to getting more power out of an old 94 325i if the engine rebuild and forced induction wouldn't be worth it?? All i'm looking is more power/performance.

Add up the cost just in parts to rebuild a motor. I think you will find your answer.

///M325i
12-08-2010, 12:29 PM
Add up the cost just in parts to rebuild a motor. I think you will find your answer.

Well i don't want to say money isn't an issue because anyone who says that would be telling a lie. I don't want to blow all my money on an engine rebuild and a nice turbo system either, but i hear you i'm not all that experienced with BMW and you clearly seem to be so thanks for the advice. I'm already looking into the cost of the rebuild i haven't decided where i'm going to do it yet. But i'll keep in mind the not worth it part.

craz azn
12-08-2010, 03:42 PM
Well i don't want to say money isn't an issue because anyone who says that would be telling a lie. I don't want to blow all my money on an engine rebuild and a nice turbo system either, but i hear you i'm not all that experienced with BMW and you clearly seem to be so thanks for the advice. I'm already looking into the cost of the rebuild i haven't decided where i'm going to do it yet. But i'll keep in mind the not worth it part.

Just for a set of new forged pistons is about the same price as a nice used M52 engine just like Dissembler suggested. It's relatively cheap, tons available, and stronger than an M50 if you seriously want to boost it. And even if you don't, it is a decent platform to start with for bolting on some go fast parts to keep you entertained for the time being.

JvzwetE36325
12-08-2010, 04:19 PM
I'm selling my m52 btw ;)

JvzwetE36325
12-08-2010, 04:22 PM
I have an M50, and yes its a strong motor but rudy is right, the m52 is a better platform for boost, forged connecting rods and crank, 84mm bore x84mm stroke. Slightly bigger displacement as a 2.8, can be further bored to a 3.0L, thick iron block (strong for boosting)

///M325i
12-09-2010, 01:56 PM
Just for a set of new forged pistons is about the same price as a nice used M52 engine just like Dissembler suggested. It's relatively cheap, tons available, and stronger than an M50 if you seriously want to boost it. And even if you don't, it is a decent platform to start with for bolting on some go fast parts to keep you entertained for the time being.

hmmm well now that i think about it, it's not all that bad if i were to swap out my 2.5L for a 2.8L but obviously keeping the m50 intake manifold.

///M325i
12-09-2010, 02:04 PM
So the bottom line is, it would be way better to get an m52 and build that rather then rebuilding an old m50 then turbo charging it. hmmmmm

JvzwetE36325
12-09-2010, 02:14 PM
You would also have to convert the M52 into obdI, but since u already have most of it on ur m50 you would be set.

dble Trouble
12-09-2010, 05:49 PM
+1 on the M52 for boosting, but if you don't go boost consider the S52. You HAVE to KNOW exactly what you want the finished product to be before you start, and DON'T deviate from the plan, that's when projects end up costing double or more than the initial budget!

///M325i
12-09-2010, 07:18 PM
+1 on the M52 for boosting, but if you don't go boost consider the S52. You HAVE to KNOW exactly what you want the finished product to be before you start, and DON'T deviate from the plan, that's when projects end up costing double or more than the initial budget!

OHHH believe me i would love to put the s52 3.2L in my car but we all can't have what we want so thats why i settled for the rebuild m50, but now i see that isn't the best way to go i think the m52 with the m50 intake manifold with boost would be the best way to go with some internal upgrades down the road. I'm going to try to stick to this set up and hope every thing goes smoothly but thats never the case lol

Dissembler
12-09-2010, 09:53 PM
You would also have to convert the M52 into obdI, but since u already have most of it on ur m50 you would be set.

gah! I hate when people say this about M52s. Why do you have to convert to OBD I? OBD II is better in every way possible. Period. You can put the m50 manifold on (which is only an upgrade depending on how you plan on using the car) and still retain OBD II

dble Trouble
12-09-2010, 11:43 PM
^^x2, in most cases OBD I conversion makes no sense. Only if you're creating your own tune is OBD I (not better) but easier to tune!^^

///M325i
12-10-2010, 09:20 PM
ok so DON'T convert the M52 into OBD I got it!! lol

tg07lq
12-11-2010, 01:55 PM
well convert to obd I if you have an obd 1 car. 1994 would be obd I (correct me if im wrong)
220k is high? haha i just rolled 450 the other day, shes still a fun car looks good and purs like a kitten (albeit maybe a kitten with a scratchy throat)

ive been tossing hte m52 swap around for a while, ive yet to price it out. im m50 non van so i imagine my gains going to an m52 with vanos and m50 intake would be quite the kick in the pants!

///M325i
12-12-2010, 02:39 PM
well convert to obd I if you have an obd 1 car. 1994 would be obd I (correct me if im wrong)
220k is high? haha i just rolled 450 the other day, shes still a fun car looks good and purs like a kitten (albeit maybe a kitten with a scratchy throat)

ive been tossing hte m52 swap around for a while, ive yet to price it out. im m50 non van so i imagine my gains going to an m52 with vanos and m50 intake would be quite the kick in the pants!

WOAHH :eek: you just hit 450? damm i thought i had a high km car lol guess not. And yah i'm pretty sure a 2.8 with vanos and an m50 intake manifold would be sweet but imagine forced induction on top of that *rockout*

///M325i
12-12-2010, 02:47 PM
OK my car is OBD I (1994) should i convert to OBD II or not? To be honest i don't know too much about the OBD I or OBD II systems. I'm getting a lot of different answers here, don't get me wrong guys i REALLY appreciate all the input but, to convert or not to convert lol

Dissembler
12-12-2010, 04:31 PM
Don't do it. When you buy an m52, you're going to need the ECU that came with and its the ECU that is OBD II. If you cannot/don't feel like integrating EWS (the immobiliser system, which is what scares most people away from keeping OBD II), just contact MarkD or TRM, and they can delete the EWS for you. Put in engine, put in your ECU, done.

richie_s999
12-13-2010, 08:09 AM
WOAHH :eek: you just hit 450? damm i thought i had a high km car lol guess not. And yah i'm pretty sure a 2.8 with vanos and an m50 intake manifold would be sweet but imagine forced induction on top of that *rockout*

You do realise that the only year the m50 did not have vanos was 1992 in the e36. The overall power out put was the same hp wise, there was a 3 or 4ftlb torque gain, the system brought the torque on at a lower rpm making it more usable.

Also the m50 and m52 make the same hp, the m52 makes 20 plus more ftlb/torque, which is where it's grunt comes from, I'd say a sweet set of cams and head work with CIA/headers, and the right tune will net u more torque in a better range then boosting and come in around the same price. Plus the possibly upgraded head internals (sooo many options) will last longer then stock ones under boost. Build the motor b4 slapping boost, it will be more reliable and you may well find you have a faster car

///M325i
12-13-2010, 11:21 AM
You do realise that the only year the m50 did not have vanos was 1992 in the e36. The overall power out put was the same hp wise, there was a 3 or 4ftlb torque gain, the system brought the torque on at a lower rpm making it more usable.

Also the m50 and m52 make the same hp, the m52 makes 20 plus more ftlb/torque, which is where it's grunt comes from, I'd say a sweet set of cams and head work with CIA/headers, and the right tune will net u more torque in a better range then boosting and come in around the same price. Plus the possibly upgraded head internals (sooo many options) will last longer then stock ones under boost. Build the motor b4 slapping boost, it will be more reliable and you may well find you have a faster car


Well aware of every thing you just stated my friend. Except for "there was a 3 or 4ftlb torque gain, the system brought the torque on at a lower rpm making it more usable" ONLY 3 or 4ftlb of torque gain well that just doesn't seem worth it to me at ALL lol. And yes i agree with you about building the motor first then going FI that way the engine would last longer and could take a nice beating once in a while. One more question though, would putting an M50 intake manifold on the M52 engine give you a 20HP gain? I read that some where.

richie_s999
12-13-2010, 11:56 AM
Well aware of every thing you just stated my friend. Except for "there was a 3 or 4ftlb torque gain, the system brought the torque on at a lower rpm making it more usable" ONLY 3 or 4ftlb of torque gain well that just doesn't seem worth it to me at ALL lol. And yes i agree with you about building the motor first then going FI that way the engine would last longer and could take a nice beating once in a while. One more question though, would putting an M50 intake manifold on the M52 engine give you a 20HP gain? I read that some where.

Are you chasing peak numbers for bragging rights or usuable power? Vanos system brought the power on earlier so iw was avalible for a longer time.

Hp gains at high Rpm are kinda useless, as are peaky motors.

What exactly are you building for

///M325i
12-13-2010, 01:14 PM
Are you chasing peak numbers for bragging rights or usuable power? Vanos system brought the power on earlier so iw was avalible for a longer time.

Hp gains at high Rpm are kinda useless, as are peaky motors.

What exactly are you building for

*no-no* my friend you've got it all wrong All im looking for is MORE POWER!! I'm just building for fun i wasn't planing on buying a 325i (e36) but as soon as i drove it and herd the sound i loved it. I don't want any "bragging rights." With an 2.8L and an M50 manifold with turbo i can take most cars on the road and thats a win for me lol And i don't really know about the VANOS system as i mentioned earlier But i would like to learn and you seem to know a lot about it. And i do agree HP gain at high RMP is sooooo useless because you cant use it. It's never there.

Dissembler
12-13-2010, 01:46 PM
One more question though, would putting an M50 intake manifold on the M52 engine give you a 20HP gain? I read that some where.

Its good for 25-30hp above 4000rpm. You will lose 10-15hp below that, or about 10hp if you have a good tune designed for that manifold.

richie_s999
12-13-2010, 02:14 PM
*no-no* my friend you've got it all wrong All im looking for is MORE POWER!! I'm just building for fun i wasn't planing on buying a 325i (e36) but as soon as i drove it and herd the sound i loved it. I don't want any "bragging rights." With an 2.8L and an M50 manifold with
turbo i can take most cars on the road and thats a win for me lol And i don't really know about the VANOS system as i mentioned earlier But i would like to learn and you seem to know a lot about it. And i do agree HP gain at high RMP is sooooo useless because you cant use it. It's never there.

Vanos is a variable valve timing system, and BMWs are not a strait line car, if you want to light to light, just drop a 3.91 diff on and go nutz

///M325i
12-13-2010, 03:17 PM
Its good for 25-30hp above 4000rpm. You will lose 10-15hp below that, or about 10hp if you have a good tune designed for that manifold.

AHHH above 4000RPM i see i see, thank you.

///M325i
12-13-2010, 03:22 PM
Vanos is a variable valve timing system, and BMWs are not a strait line car, if you want to light to light, just drop a 3.91 diff on and go nutz

Soo i've herd, the good old 3.91 differentiation never fails lol So VANOS is a valve timing system hmmmm did NOT know that. But i'm pretty sure that 3.91 is a bank breaker noo??

IgnitionDelay
02-26-2011, 02:36 AM
The condition of the chassis being considered is what determines whether or not the build will be worth it. Turbo-charging a power-plant that has not been boosted from the factory (produced in large numbers) can be very expensive.

///M325i
02-27-2011, 04:43 PM
The condition of the chassis being considered is what determines whether or not the build will be worth it. Turbo-charging a power-plant that has not been boosted from the factory (produced in large numbers) can be very expensive.

Yah so i've been told it can be expensive.*thmbsdwn* And you pretty much answered my other question, the chassis has to be in good condition ehh i don't really think mine would be since i have a 94 e36 325i but you never know i haven't gotten my chassis checked ever.