The comprehensive DOHC engine swap thread.

[IanS_in_Oz]

Hi all, got a couple of questions. I've got the M52 2.8 with OBD II in the E30 and now running, except for a slight drivability issue.
When on a contstant throttle setting, at any speed, it will start coughing slightly and gets jerky. When I lift my foot, it backfires a lot on the overrun.
At idle, it idles smoothly for about 30 secs, at around 600 rpm then it drops to 500, and sounds a little lumpy or fluffy. Like its fueling up.
Any ideas on the cause?

Also I have the E30 A/C fan in front of the radiator. How do I wire it to activate when the car gets hot

Here's some pics of the car:

[BimmerTim]

I made my own.

[Boosted E30]

Cool thanks, also what do you gusy do for exhaust setup? Do most of you just run headers and then the factory system after? I ask because i have my 3" exhasut from my turbo setup but i think that might be a bit over kill for a NA motor thoughts on this? I also may have access to a reworked factory system with a SS rear muffler.

[BimmerTim]

You have to use the 328is drive shaft. The rear flange to the diff on the M3 will have a 6-bolt CV style joint and the 328is has the 4-bolt u-joint style.

[Boosted E30]

Im going to be doing a S50 swap and just have a couple questions, I have the complete M3 that I'm getting the engine from and I'm going to use the transmisson from that car, can I use the drive shaft aswell or do I have to get the 328is drive shaft?

Can I use my stock brake booster and just move it over 1/2" or is it better to get the E21 booster? it seems most people go for the e21 booster is there any special reason for this?I would rather use the money for the e21 booster for headers or somthing.

[gman325is]

Man this thread can drive you insane trying to get answers to questions. Some one needs to brake this thread into sections or chapters!!

Anyway, I'm trying to figure out what brake MC to use with my E30 ix booster? Is it the 25mm from an E34 M5? Or can i also use the MC & reservoir from a E32 735i/iL?

And for those of you with the NV M50 set up with the E36 325i tranny, do I need to change out the diff. or can I leave my stock one in? If I need to change, I probably should go with the 3.25 lsd to not have it screaming loud which will happen if I did the 3.73 lsd?

I just used the Master Cylinder that came with the ix booster, works great.

[SamE30e]

Brake reservoir off a E32 7 series v8 works. You need the fittings, rubber grommets, and reservoir. You can use 1/4" fuel line for lines, or get some braided from BMW. Only problem is, you need to get a 1/4" T fitting for the clutch or run a separate reservoir for the clutch. I mounted mine to the back part of the air box bracket.

[dinanm3atl]

Cool. I have an aluminum E36 radiator.

[MattM]

Couple of cooling system/cooling questions I wanted to throw in here.

75 Degree Thermostat with no mech. fan but add an electric fan?

What hoses to use? Seems some say E36. Some say E34. Using E36 aluminum radiator.

Anything other tricky cooling things going on? Trying to buy up all the small parts to have them ready.

hoses depend on rad and which M/S5x you get, with late E30 rad, M50, i used E36 hoses, mine fit with no mods

I still have the stock thermostat (92NV E34) and electric fans on sensor(from E30) the guage sits dead in the center of the temp guage. Fans only kick in if the car is idling for 5+ minutes when at temp

[dinanm3atl]

Couple of cooling system/cooling questions I wanted to throw in here.

75 Degree Thermostat with no mech. fan but add an electric fan?

What hoses to use? Seems some say E36. Some say E34. Using E36 aluminum radiator.

Anything other tricky cooling things going on? Trying to buy up all the small parts to have them ready.

[87e30]

Man this thread can drive you insane trying to get answers to questions. Some one needs to brake this thread into sections or chapters!!

Anyway, I'm trying to figure out what brake MC to use with my E30 ix booster? Is it the 25mm from an E34 M5? Or can i also use the MC & reservoir from a E32 735i/iL?

And for those of you with the NV M50 set up with the E36 325i tranny, do I need to change out the diff. or can I leave my stock one in? If I need to change, I probably should go with the 3.25 lsd to not have it screaming loud which will happen if I did the 3.73 lsd?

In the case of your diff, what do you have there now? Whatever you have in there will work, just the gear ratio might not be ideal. Well, so long as the flange matches up with the new driveshaft that you are going to use, which it should. I'm not fully sure, so someone correct me if I'm wrong but I'm sure you'll be fine with whatever diff you have. (if you have an eta (aka 2.91) then you probably want to get something shorter (3.25, 3.46) for performance, but won't need to.

[E30 Devil]

Man this thread can drive you insane trying to get answers to questions. Some one needs to brake this thread into sections or chapters!!

Anyway, I'm trying to figure out what brake MC to use with my E30 ix booster? Is it the 25mm from an E34 M5? Or can i also use the MC & reservoir from a E32 735i/iL?

And for those of you with the NV M50 set up with the E36 325i tranny, do I need to change out the diff. or can I leave my stock one in? If I need to change, I probably should go with the 3.25 lsd to not have it screaming loud which will happen if I did the 3.73 lsd?

[motorsports_3]

After doing some research I am pretty sure if you use a G250 tranny, you use the driveshaft it comes with, but with an e30 CSB.

[BimmerTim]

If you use an E30 trans, you use an E30 driveshaft. If you have an E36 trans, you use an E36 328is driveshaft. There may be some other combos, but these are tried and true.

[motorsports_3]

So you are saying with an M50 and G250 you would use a standard e30 manual d/s?