Exploring engine swop options for my coupe (72 Csi). Looking at a Euro spec 91 E34 M5 engine. Has anyone done this and what are the main issues/ challenges?
Engine swop 91 E34 M5 - S38
- Thread starter TRIPPFONTAINE
- Start date
x_atlas0
Well-Known Member
It is pretty much the same as any other M88/S38 swap. There have been many threads about the topic, but the bigger stumbling blocks include:
Getting Motronic (in your case) 1.2 to work in a new chassis
Pounding back the firewall to fit the wider S38 head
Dealing with a very tight radiator / mech fan fit
Switching the brake booster setup to clear the S38's variable intake system
etc.
Getting Motronic (in your case) 1.2 to work in a new chassis
Pounding back the firewall to fit the wider S38 head
Dealing with a very tight radiator / mech fan fit
Switching the brake booster setup to clear the S38's variable intake system
etc.
rb1971
Well-Known Member
I'm doing this swap right now.
Haven't had any problem with the firewall (the engine fit relatively well), but we are having to go with an electrically-switched fan due to clearance issues.
My engine came without a DME. Locating one in the states was difficult (I think I got the last one here, actually). We coupled this to a Split Second setup. This setup alone cost about US$2500 - not cheap.
With respect to the brake booster (also an issue), we determined that the booster from an M1 of all things fits well. As you can imagine it is also cheap and widely available.
Air intake is another general issue. Our approach was to build an airbox in the front left with intake from an Alpina-style airdam in the front. This and other changes required moving the battery to the back to get extra room.
Then you will probably want to use the matching tranny which means rebuilding the driveshaft.
Haven't had any problem with the firewall (the engine fit relatively well), but we are having to go with an electrically-switched fan due to clearance issues.
My engine came without a DME. Locating one in the states was difficult (I think I got the last one here, actually). We coupled this to a Split Second setup. This setup alone cost about US$2500 - not cheap.
With respect to the brake booster (also an issue), we determined that the booster from an M1 of all things fits well. As you can imagine it is also cheap and widely available.
Air intake is another general issue. Our approach was to build an airbox in the front left with intake from an Alpina-style airdam in the front. This and other changes required moving the battery to the back to get extra room.
Then you will probably want to use the matching tranny which means rebuilding the driveshaft.
x_atlas0
Well-Known Member
Rather than use the expensive and relatively fragile Getrag 280, many people end up using the Getrag 260 or 265 instead.
Has anyone ever tried to squish the V12 into and E9?
bmw art car
Well-Known Member
Have you ever seen the size of an M70 or M73 and the amount of electronics
required to make it run?
I am on the lookout for a S54... has anyone done that engine?
johanaxelson
Well-Known Member
I have a 91 535 engine in mine. Tight fit but it works.
Some points apart from those already mentioned.
- went for a hydrualic brake booster instead. For good and bad but works well.
- had to put old "oil tray" on the new engine for it to fit.
- problem with airfilter, where to fit it and how to get one big enough in there and make it look OK
/johan
x_atlas0
Well-Known Member
The electronics are a nightmare. A group of kids from MIT took quite some time to swap one into an E30. I suppose you could go full standalone with a high-end Motec (for biVANOS control) or lock the VANOS and use a simpler system at reduced power.
bmw art car
Well-Known Member
was looking for a parts car M3. Something between 2004 and 2007
x_atlas0
Well-Known Member
That's what the MIT kids had, and it still took them more than 6 months. Rob Levinson (of UUC) has done several S54 swaps as I recall, you could ask about it. There's also a few S54 swap threads floating around. It is not trivial.
Plus, a slightly modded S38B36/B35 will make the same rwhp and more tq than the S54, based on the dynos I have seen. The S38B38 destroys the S54 in terms of power output.
rb1971
Well-Known Member
<i>That's what the MIT kids had, and it still took them more than 6 months. Rob Levinson (of UUC) has done several S54 swaps as I recall, you could ask about it. There's also a few S54 swap threads floating around. It is not trivial.</i>
Seconded. When I started on my project I had access to an E46 M3 that had been in a rear-end accident - and therefore all the electronics we could have wanted, plus a low-mileage engine, etc. Still went with the S38B38. Well, it was also sitting right there next to the car, staring me down...
Seconded. When I started on my project I had access to an E46 M3 that had been in a rear-end accident - and therefore all the electronics we could have wanted, plus a low-mileage engine, etc. Still went with the S38B38. Well, it was also sitting right there next to the car, staring me down...
bmw art car
Well-Known Member
I talked to Korman today and he said pretty much the same you did.
The 'missions' has been updated to a M6 engine
2800csm5
Well-Known Member
I have two coups, one with an S38 from a 91 E34 M5 and the other have a M30 from a 89 635csi. Both have getrag 265 5 speed and 3:64 diff. Both installations were straight forward and fairly easy to do. Except for moving the battery to the rear and replacing the brake boosters to 2002TII boosters, everything fits perfectly. See pictures in the registry.
http://www.e9-driven.com/RegistryView.asp?RID=2825
http://www.e9-driven.com/RegistryView.asp?RID=2825
ScottAndrews
Well-Known Member
I would think the electronics woudl be fairly straightforward, as long as you have the DME for that engine. If not, then I'd start with abare unit as several here have described (Megasquirt or Split Second). As long as you have the I/Os to run everythng on the engine, the electronics is pretty easy (wiring and signal conditioning). The crunch is the software. You have at least injector control, timing control, and VANOS outputs. Maybe a few others, and various inputs (air temp, air flow, crank position, TDC, throttle position, engine RPM, maybe a torque sensor, etc.) and so you have a complex engine map that can probably only be really worked out using a lot of dyno hours.