s38b36 conversion

[eamo]

after looking into the s62 conversion for my m535i i have decided its not the way to go for me.

however i have come a come across a very cheap 1991 e34 m5 with the s38b36 engine

i had a quick search but cant find a definitive answer on this

do i use the m5 box?
which prop?
exhaust/manifold?
diff?
rad?
mounts for engine/box?

any info greatly appreciated

thanks

[andy535iyes]

I have an '88 e28 M5 with the s38b36 conversion. It was done by the previous owner and I do have the receipts for the work.

Not sure what you are referring to about the "M5 box"
A drive shaft was not on the parts list
Euro headers for exhaust
diff is original 3.91 although I would like to try a 3.73
radiator was new from a 535, not sure if e28 or e34, realoem.com did not recognize the part number.
There is a note about welding the rt. front motor mount bracket.

Also some custom work was needed to hook up the oil cooler and A/C.

The car can move it move it.



Let me know how I can help,
Andy

[Rich Euro M5]

Andy,

The OP's conversion will require quite a bit more work. The reason your conversion was a piece of cake is because the S38B35 and S38B36 are dimensionally the same engine.

To install a S38B36 into an M535i will require a lot more work than doing the same installation into an E28 M5.

Rich

[cgraff]

Andy,

The OP's conversion will require quite a bit more work. The reason your conversion was a piece of cake is because the S38B35 and S38B36 are dimensionally the same engine.

To install a S38B36 into an M535i will require a lot more work than doing the same installation into an E28 M5.

Rich

Por que?

-Chris

[mooseheadm5]

It fits jsut fine, but the passenger motor mount will not bolt up and the headers may not fit. The harness will need to be adapted, you may need a different radiator. The box (transmission) will bolt right up, as will the flywheel.

[mercury26]

I believe Koala Motorsport makes adapters to fit the S38B36 motor into the earlier chassis.

http://www.koalamotorsport.com/proddeta ... od=m30ls38

Cheers,

Chuck

[eamo]

thanks for the feedback guys

ok - so i spoke with a guy in the uk last night who has already done this using his e28 m5.

he used the nearside e28 m30 engine mount, but the offside will not fit and you'll need to fabricate one or buy one. (somewhere in the US sells them i think )

You could use the M5 box but you would need to get your prop shortened to fit. he also rekoned i could use my dogleg box and prop
Also you would need the radiator and exhaust manifold from an e28 M5. A custom radiator and Fritz manifold http://www.fritzsbits.co.uk/exhausts.htm may be the way to go.

The e28 M5 has a large case 3.73 diff while the e34 m5 is 3.91. the nearest to this would be the 3.64 from a Highline 6 series, or you could get a diff rebuilt using the e34 innards into your e28 large case.

There would be the oil cooler and coolant plumbing to sort and you would need to move the expansion tank mount and resite it somwhere else as it's in the way of the inlet manifold. you also need to move the power steering fluid reservoir forward a bit too

The airbox occupies the space where the battery sits so you will need to move the battery to the boot.

also as you know work will be required to match the e34 engine loom to the e28 as the connectors don't match. The ECU on the e34 is under the bonnet so the engine loom isn't long enough to fit the ECU behind the glovebox in the original e28 position.

so what ya think of that!

[cgraff]

thanks for the feedback guys

ok - so i spoke with a guy in the uk last night who has already done this using his e28 m5.

he used the nearside e28 m30 engine mount, but the offside will not fit and you'll need to fabricate one or buy one. (somewhere in the US sells them i think )

You may need both mounts - depending on what bosses are on the block.

As has been said, Koala Motorsports has mount adapters available.

You could use the M5 box but you would need to get your prop shortened to fit. he also rekoned i could use my dogleg box and prop

Or you can use the M5 driveshaft.

Yes, the dogleg gearbox and driveshaft out of the E28 will fit.

Also you would need the radiator and exhaust manifold from an e28 M5. A custom radiator and Fritz manifold http://www.fritzsbits.co.uk/exhausts.htm may be the way to go.

Since you are a RHD country, you will most likely need custom headers, unless you want to use the stock UK M5 headers, which will fit just as well.

You don't need a custom radiator. The E28 535i unit will fit and has the outlets in the correct spots.

The e28 M5 has a large case 3.73 diff while the e34 m5 is 3.91. the nearest to this would be the 3.64 from a Highline 6 series, or you could get a diff rebuilt using the e34 innards into your e28 large case.

The EURO M5 E28 has a 3.73 large case LSD. US models had a 3.91 large case LSD. You can use any diff you want - it's a matter of what gearbox you have. Since you're going to either be using a M5 (Getrag 280) or a dog leg, you will have to consider the top gear. 5th in the 280 is 0.81:1 and thus can use a 3.73 or 3.91 diff with no issues. The dog leg has a 1:1 5th gear, and thus if you want to keep overall gearing similar would require a 2.93, 3.07, or 3.25 rear diff. (3.73*0.81 = 3.01, and 3.91*0.81 = 3.17). A 3.07 would be ideal, which is what came stock on euro 535s and M535s with the dog-leg transmission. And it's a big case differential.

There would be the oil cooler and coolant plumbing to sort and you would need to move the expansion tank mount and resite it somwhere else as it's in the way of the inlet manifold. you also need to move the power steering fluid reservoir forward a bit too

The biggest issue with the coolant plumbing is sorting the expansion tank location - it has to be on the passenger side due to the S38 B36 coolant plumbing. You will then have to plumb the coolant hoses to the cabin heater under the intake side.

The oil cooler plumbing is not that difficult. You can use the E28 canister and oil filter housing - it's just that you need to block an oil passage in the S38 B36 / B38 block that is a drain. The PN can be found in the E23 745i ETK diagram.

The airbox occupies the space where the battery sits so you will need to move the battery to the boot.

Moving the battery to the trunk isn't easy - as you have to pass thru the large battery cable to the front of the car and match up the electric wiring. However, to get the car driveable you don't need the airbox, but a cone filter would suffice.

also as you know work will be required to match the e34 engine loom to the e28 as the connectors don't match. The ECU on the e34 is under the bonnet so the engine loom isn't long enough to fit the ECU behind the glovebox in the original e28 position.

so what ya think of that!

On top of that, the B36 has air injection into the exhaust and an air pump. But you will need to keep some of the vacuum control in order to operate the intake plenum valve. This is reasonably easy to see - there is a technical sheet on this system available at an E34 M5 website. I forgot the details, but you must keep this issue in mind.

Oh, and the wiring loom is perfectly long enough to go into the glovebox. Remember that the E34 engine compartment is much larger than the E28. Many a time B35 E34 535i engine wiring harnesses have fit into E28s.

-Chris

[mooseheadm5]

All correct, but I would not pair the dogleg gearbox with a 3.73 or 3.64. In the US, the E28 M5 got a 3.91 and an overdrive 5th gear. I would probably prefer a 3.25 or 3.45 (though that would be excessive) diff if using the dodgleg. Your M535i came with a 3.07 large case diff, I believe. I would not worry too much about the large case diff unless you plan to track the car. For the street a medium case diff should do just fine.

[Rich Euro M5]

Here is the E34 M5 Technical Paper Chris mentioned in his detailed reply above.

Rich

[Rich Euro M5]

I wouldn't use the Dogleg box, BMW moved away from that gearbox in the M6 follow on to the M635Csi because it wasn't up to the task of dealing with the increased power of the M88/3 engine. If the dogleg was weak behind the M88/3, the S38B36 will be too much for it as well. I'd suggest the G280 gearbox with a 3.73 or 3.91, the standard E28 M5 driveshaft will bolt right in.

Rich

[eamo]

just so that i understand its best to use the 280 gearbox as its stronger than the dogleg (plus i can make lots of $$$ too!). the 280 gearbox is the exact same gearbox thats in the e28 m5 and e34 3.6 m5 so i can use the 280 box from the e34 m5 that i have

re prop then i have 2 options as i see it
1: an e28 m5 prop wihich will bolt on the e34 m5 box and my m535i diff with no issue or
2: the front part of the e34 m5 prop and the rear of the e28 m535i prop. i accept the the prop will need to cut, welded and balanced

that means then i have to have a diff with a 3.9 ration which is what was in the e34 - i can swap the innards over from the e34 diff into the e28 diff

ps - can the e34 m5 prop be used to go from the e34 box to my diff?

[cgraff]

just so that i understand its best to use the 280 gearbox as its stronger than the dogleg (plus i can make lots of $$$ too!). the 280 gearbox is the exact same gearbox thats in the e28 m5 and e34 3.6 m5 so i can use the 280 box from the e34 m5 that i have

re prop then i have 2 options as i see it
1: an e28 m5 prop wihich will bolt on the e34 m5 box and my m535i diff with no issue or
2: the front part of the e34 m5 prop and the rear of the e28 m535i prop. i accept the the prop will need to cut, welded and balanced

that means then i have to have a diff with a 3.9 ration which is what was in the e34 - i can swap the innards over from the e34 diff into the e28 diff

ps - can the e34 m5 prop be used to go from the e34 box to my diff?

1 Yes.
2. No. the E34 M5 prop will not be the right distance, even if using the front half. It's dependent on the hardpoint locations of the gearbox, rear diff, and center bearing mount. I think this is a non-starter.

If you use the Getrag 280, you will need either a 3.73 or 3.91 diff. It doesn't matter really where you get it, even a medium case diff can reasonably well take the power.

As for swapping innards, yes, you can swap the crown and pinion gears, but you will need the right tooling to correctly pre-load the gears and bearings. If you don't you'll effectively burn out your diff (the bearings).

-Chris

[Rich Euro M5]

You might get away with using the Dogleg prop. I know a couple of guys here in the States have swapped G265 boxes into their M5s and used the G280 prop. I can't recall if the G280 prop was longer or shorter, but it did work.

It wouldn't hurt to try before you expend the funds to acquire the M5 prop or have yours modified.

Chris is spot on about swapping the diff gearsets. I've seen the setup procedure, setting the pinion preload involves using a torque gauge which reads in ounces. You have to measure the resistance of turning the pinion while carefully torqueing the pinion nut. Rather than utilizing shims as most diffs do, the BMW diffs in the E28 utilize a crush sleeve. Screw up and you strip it down and replace the sleeve.

Rich

[eamo]

what diff can i swap onto my e28?

will a e30 3.9 fit

what about a diff from a e24 or e32?

what are my options

thanks

[Rich Euro M5]

what diff can i swap onto my e28?

will a e30 3.9 fit

what about a diff from a e24 or e32?

what are my options

thanks

You can use any medium cased E30 diff. In the US market we look for diffs from the 325i/is, which is typically a 3.73lsd. I seem to recall some E30 325i cabrolets with Auto boxes had a medium cased 3.91 possibly a 4.10. You can also source a diff from any late E24, or an E23. Some E24s have 3.64 diffs, and the M635Csi will have a 3.73 lsd. You can't use the small cased E30 diffs or the E32 and E34 diffs.

Rich

[eamo]

lads

many many many thanks for all your help and info

[bm0p700f]

Good to know a medium case diff is strong enough. I suppose it must be as the E30 V8's S50's, V12 in their cars as well as turbo them.

[mooseheadm5]

Not to mention all of the seriously powerful turbo E28s here that run them. The medium case does just fine. The larger plates in the LSD supposedly can handle more power, but unless you plan for competition, I would skip an endless search for an expensive and not exactly necessary diff.

[Mike in Seattle]

Not to mention all of the seriously powerful turbo E28s here that run them. The medium case does just fine. The larger plates in the LSD supposedly can handle more power, but unless you plan for competition, I would skip an endless search for an expensive and not exactly necessary diff.

Remember he is in Europe, so he has access to an abundance of large case diffs. All M30 powered cars over there got the large case diff and it might be just as easy to source a large case diff as a medium case diff.

[johnnyjumps]

how much would it cost to have something like this done if I had the motor and the 280 and wanted to drop it into my 535 but don't have the expertise to do something this big.

Thanks,

John

[johnnyjumps]

how much would it cost to have something like this done if I had the motor and the 280 and wanted to drop it into my 535 but don't have the expertise to do something this big.

Thanks,

John