Engine conversion possiblities

[welshy255]

right here goes!..

Im getting more and more tempted to make a project of my baur, its in great condition now but really want to take it to the next level but the engine possibilities seem so varied. i also have a pipe dream for a perfect setup but pretty sure nobodies ever tried itor if its remotly possible!!

i'll just brainstorm some ideas on here and see what your guys opinions are, ive got a limited mechanical knowledge but not to the scale were talking here!
ENGINES
1- S52 engine, manual box and diff, all ancillaries. vanos/ews/traction/ac delete and standalone ecu as oem would be nitemare! custom mounts. susp and brake custom/e36 m3 where possible

2- m20 with either turbo/supercharger setup. mines currently a 323 auto so poss use the current block. im not tempted with turbos but a good supercharger kit could by useable and need less fabrication to the shell.

3 the dream!!!! A s54 m3 engine, but with a smg box and e46 clocks and looms/ecus. with the rear end to match. m3 steering components would probably be needed to retrofix the changes. all sensors/ vanos deletes, this would mean no optional traction control, ac but hopefully dumb now the looms!
ive never seen this done to a road car for good reason i guess, but is it impossible?



SHELL

obviously a 82 baur shell isnt the most 'taught' so to what extent is the norm when carrying out a 300bhp+ conversion like this?

if you went for a s52/52 engine a full cage would be needed, so rear towers with horizontal bars, centre and a-piller, the through to front towers. then i guess it would be custom subframe to mount the engine slightly further back. cut back bulkhead and centre tunnel? then use custom/ m3 suspension and brake parts where you can?
hence the reason a custom m20 engine could be a more realistic option. i know its never gona be cheap either way!

any info from guys who have undertaken something like this, or know of any sort of garage would take something like this on!!! i thought trying a company called z-cars, they build bike engines into classic minis and some of their engineering work is top notch- for designing a cage or semi spaceframe with mounts built in. then buy a crash damaged or even straight m3 to pilfer.

If you got this far for reading my newbiee speak!

[nas80]

Ive done a few m52 conversions..

Read the modified section of owners gallery. It's too much info for me to type out

[Jeroen]

Welcome here! Depends on the budget, what you can do yourself and what you want to do with it I guess. What do you expect of the car? Fun to drive on the road, trackday, straight line speed? M50/M52 is relatively easy and with a B28 or B30 you easily have in excess of 210 BHP without too much hassle. Enough topics on similar conversions here on the forum indeed!

I'm convinced a S50/S52/S54 conversion will require much more effort, modifications and money, but it's not new. I've seen several S50/S52 conversions over the years and there's a S54 conversion coming up from the Netherlands as well. Mind you, that is including ABS and traction control. But the guy currently building it has over 20 years of experience on extensive conversion and has his own business around that kind of work. I've seen most other attempts fail because people never expect to have to put 50+K in.

Archive pic of a trackday S50 car



A few pics of a mate's S50 conversion

[polov8]

Wow, that last car is a beauty! What size wheels are those, they look like 17's?

So far as conversions are concerned, my advice would be to try and sample a car with a more modest transplant. the jump from a 323 to well over 300hp in an E21 is going to be quite drastic! It might be that a 240hp 3.0 or something, which is alot cheaper than an S54, gives you the thrills you want without the cost. I know I've gone down the big swap route in the past (There's a reason my name is Polo V8) and failed to finish it, and it's depressing, when you think for half the time and a quarter the cost you could be out enjoying your car instead of watching it sit on axle stands.

[welshy255]

Yeah agreed, its easy to get over ambitious and go past the point of no return. I'll be at gaydon so hopefully have a good look round and speak to people like nas who really know the ins and outs, and see where it goes from there.

Have you ever tried a s14/s52 conversion nas? As you seem to be the man in the know about these things?

Cheers,
Ash

[nas80]

an 193hp m52b28 in an e21 is pretty damn fast, it will really put a worrying look on an e46 m3 owners face when he struggles to keep up. The s54 is pretty wild too, but you have to upgrade everything, if you want to spend about 10k on parts and fabrication then yeah fair enough.

the rear end is a challenge, you will probably find that a different de dion style diff will be less work then using a bmw item.

This is my setup

m52b28 - US spec m3 cams, big bore throttle body and m50 intake, specific e21 24v remap with EWS / 5k rev cut disabled - people usually get 240/250hp from this setup, I will be running on a dyno once its run in.
Custom engine and gearbox mounts
e36 m3 gearbox, m20 flywheel that's been lightened and a paddle clutch
custom sump (for ground clearance)
custom steering link to clear manifolds
modified manifolds and fully mandrel bent n tig welded, t304 stainless exhaust.
forest rally spec WRC core custom radiator
BMW e12 LSD, on a modified rear axle (I still need to uprate drive shafts)
brake bias pedal box, which is simple in operation but stupidly complicated to fit in an e21.
wilwoods on the front on stock disks (but I will be upgrading that to a much bigger set) 323i rear disk conversion with bigger e30 calipers
GAZ coilovers, rear beam modified to adjust camber and toe, front adjustable plates, fully polybushed
a bit of chassis strengthening using strut bars front and rear and a cross link on the front chassis legs
recaros because stock seats are no good when you have that sorta power and handling.
electric speedo conversion.


the m52 is a great engine - I have a spare m52b28 with a spun bearing and i have scored a dirt cheap 330ci engine block that's got a blown head gasket, I will be making a frankenstein m52b30 engine. the reason I am a fan of the 24v, If they break you can pick another up for like £300 - they weigh nothing too. I can easily manouver one across the garage without a crane and not killing myself.

You have to remember the s50 is made of cast iron so it weighs a lot, when I had the m50b25 (also made of cast iron) you definitely felt the weight of it (50kg more than the alloy block) esp when turning in and that's why I had to spend another 600 on suspension improvements on top of the gaz coilovers to dial out the extra weight.


in a baur. now that's pretty interesting really. you could do it that's not the problem, but chassis flex is - you have to remember that you putting DOUBLE the power what BMW imagined when they designed it.

[nas80]

S14 has been done and because its based on the m10 really easy to drop in. but good luck getting one of them cheaply or finding one, which is why I always go for the m5x engines, dirt cheap and everywhere.

Cant go gaydon show now, my friends have basically forced me to go retro rides show, which is on the same day because it is twice as awesome as Gaydon, I will however be at bmw show at santa pod. Defo having a blast up the strip, hope to see a mid 13 to low 14 second quarter.

[Jeroen]

For torque and horses and affordable fun I can only agree on a M52 or M54 conversion. S14 gives you way more balance because of reduced engine weight and because it sits further behind the front crossmember, but you're only be using that advantage on the track or on twisty roads I guess. In any other situation ie regularly in the streets the tons of extra bottom end torque of the 6 cil engines will make it easier to run so prolly more fun, and a lot cheaper indeed.

... in a baur. now that's pretty interesting really. you could do it that's not the problem, but chassis flex is - you have to remember that you putting DOUBLE the power what BMW imagined when they designed it.

Agree, E30 Baur models are just as rigid as the 2 door closed examples. But and E21 Baur defo has more chassis flex than a closed version. And BMW didn't even do any designing there, I reckon they could not come up with a decent convertible and decided that Baur offered an acceptable alternative.

[welshy255]

Thanks for the replies gents. The m52 will be the easiest route to take, but its a bit of a double edged sword really. From what i gather chassis work will still be required if i put in a m52 at a reasonable state of tune (say 250bhp), thats why im tempted to push a step further on the engine side as the chassis will need upgrading either way, it could then give more scope to get the right front suspension package in place. I have seen a few supercharged b25's which would be insane, and probably weigh much less than a s52 block.

I should be at retrorides, heard mixed reports about gaydon the last few years but need to attend a show, the baurs hardly seen sunlight the past year

Sorry about all the pub chat aswell, i can imagine everyone and their grandma have contemplated swaps like this and gave up before the first hurdle!!!!

[nas80]

Sorry you did ask about the S54, its the same as the m52 because it accepts same engine mounts and has same gearbox options, the issue with the s54 is the wiring loom / ecu, Ben on the forum used a standalone on his, but I am very sure you can get some canbus emulator box now..

I forgot to add on my list that I had to go get a custom made propshaft, this was not cheap but for what it is probably still good value as I no longer have a guibo to tear up (I do go through a lot of them rubber ones!).

The reason I did the swap (initial one a couple of years ago) was totally because some idiot in a prius beat me off the lights and my crappy m10 could not keep up. That was the incentive and as I was borrowing a friends drive the option to list it on ebay as a "unfinished project" wasn't an option either.

Nas

[welshy255]

Modified m52 looks to be the way forward!

[trash-berd]

The reason I did the swap (initial one a couple of years ago) was totally because some idiot in a prius beat me off the lights and my crappy m10 could not keep up.

This pretty much sums up owning a 320i for me right now.