e36 full rear end? weld in mounts

[318tian]

first off, i know our rear ends are different from other e36 cars. what i want to know is if i remove to spare tire and rear subframe can you mock up and weld in the mounts off say. an m3 and have the rear end work? i mean is the frame the same. i want to take my rear end out and cut off all mounts to the car and weld in the mounts to hold the e36 rear end and big diff. has anyone done this? could someone who has both a ti and regular e36 tell me if the locations for the e36 mounting points for the trailing arms are on the ti.

[CirrusSR22]

Well anything can be done with enough work, but the differences are major. The rear frame is not the same at all. The 318ti has two subframe mount studs, both outboard. The other E36 cars have four subframe mounts inboard. The standard E36 also mounts the trailing arms off the body wheras the 318ti mounts the semi trailing arms off the subframe. A huge difference.

At a minimum you'd have to relocate the subframe mount studs to the proper inboard locations, even then they probably are not at the proper height. They'd also need to be welded securely to the frame, but not that the stock subframe stud mounts are extremely tough as they pull out occasionally.

Also you'd need to cut into the body to attach the E36 trailing arm brackets. Those would need to be attached in a fairly exacty location which would be tough to figure out without a fully assembled, standard E36 on hand to measure and compare. Part #17. http://www.realoem.com/bmw/showparts...04&hg=33&fg=30

On top of that you'd need to custom make a mount to attach the two ears of the standard E36 diff.

It would be interesting, but expect to do major cutting, welding, sheet metal, etc....

[Philly]

our cars were engineered with this style rear-end for a reason... Id take this setup over any E36 rear setup for a few reasons.

If you really want a "upgrade" without totally hacking your car up, go ZM3 setup. I think its close to a complete boltup. Not 100% on that but I know it would be MUCH easier than your ideas.

I notice you talking about a bigger diff (which is almost pointless unless you have big power plans), but another option is to go with an Mcoupe differential like me, with E30 shafts... and maybe add some PU bushing and a slightly larger swaybar.

A properly setup TI suspension will run circles around any E36 setup.

[cooljess76]

Lol Philly, you pretty much just said EXACTLY what I was going to post about an hour ago. I actually started typing, but then I realized how stupid this thread was and decided not to waste my time. The whole idea is just crazy talk.

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[mohaughn]

Running a dual ear diff is a popular upgrade on high powered z3m cars. There is a company that has pretty much perfected the technique, and it is really the way to go if you are wanting to run seriously huge horsepower numbers. Eventually the single ear diff hanger won't be able to handle the high HP and torque.

That being said, it still uses the same rear subframe and just adds provisions to make the standard E36 style diff work. And there are plenty more reasons to want to use the standard e36 style differential if you are making huge horsepower.

Trying to switch out the rest of the rear suspension would be a stupid task to undertake if you are not a mechanical engineer. Suspension components are not just plug and play like that.

[cooljess76]

^^^IIRC, Rogue Engineering makes that kit.

[mohaughn]

Originally Posted by cooljess76

^^^IIRC, Rogue Engineering makes that kit.

RE makes the upgraded dual ear diff cover. Which is comparable to the Z3M diff cover for our diffs. Offers more oil capacity and has the fins on the bottom..

It is Randy Forbes at Sports Cars Plus that does the dual ear diff modification for the Z3. I've been told it can be done on a Ti, but it is not as simple as using the Z3 kit as the floor of the Ti is different.

[318tian]

funny you say that. im actually in college for mechanical engineering. so far the only unique thing on my car is the alpine double din screen and climate control relocation. had to sut into the HVAC and make the climate hoses longer. i posted a thread with pics. i plan on swapping over everything off a wrecked m3. and i mean EVERYTHING. i want to pull the entire wiring harness and have electronic climate controls, better abs system, and many other little m3 goodies. im wanting around 375hp so yes i want a bigger diff. and i like the idea of a double ear diff. i dont like the trailing arm suspension in our cars. its one of the most obsolete things on the 318ti. i was originally thinking mz3 rear end with some sort of bigger LSD. i just imagine my car jumping right off the rear subframe completely with around 350ft of torque. i get $13000 a year for college and it all goes in my ti. so far i have a running 98 ti that i paid $1200 for the chasis and $650 for the parts car with a new motor and everything for my 5 speed conversion. ive been parting the rest of the other car and i spent $1200 on alpine iva-w205, 2 12" type r's, memphis MCD-1000, ported probox, 2 guage wiring, and 2 farad capacitor. it sounds nice . need some nice door speakers and im going to put tweeter where the stock ones are. i dont want it too flashy.

[318tian]

oh and i know this would require cutting welding and maybe some sheet metal fabrication. im thinking the side of the car should be similar to e36 and i could cut into the frame behind where the subframe hooks on to mount the trailing arms. and the spare tire would most likely have to go. and if i had the whole wrecked m3 i could cut off the mounting points for the e36 suspension. i need to know if the rear shock towers and the shocks moints are the same as the e36 cars. basically i was just wondering if the top of the shocks moint in the same location and if the frame above the diff is close enough to the e36 to weld the diff mounts up to it. and if the frame is the same behind the back of the sideskirts so i could cut in and weld the trailing arm mounts. i understand this wouldnt be very simple. and thats fine.

[cooljess76]

Originally Posted by La.ti,racer

...im wanting around 375hp so yes i want a bigger diff. and i like the idea of a double ear diff. i dont like the trailing arm suspension in our cars. its one of the most obsolete things on the 318ti. i was originally thinking mz3 rear end with some sort of bigger LSD...

^^^This statement is laughable. Sounds like you've been listening to those d-bags on bf.c. There's absolutely nothing wrong with trailing arm suspension, and FWIW, Z3's, and Mcoupes use it as well as the Ti. BMW designed these cars with that particular rear end for a reason, and it wasn't to save money. If that were the case, they wouldn't of used it on an s52 powered Mcoupe! That being said, I do wish you the best of luck even though I think your idea is a bit unrealistic. If you manage to pull this off, I'll be impressed, but still see no point in it. Let us know how everything works out, may the force be with you son!


BTW, If you come back asking us how to weld a trunk onto the Ti, well that's where I draw the line

Hey, since you're going to be welding an e36 M3 rear end onto your Ti, wanna buy my 3.23 LSD?
http://forums.bimmerforums.com/forum....php?t=1231698

[Philly]

just curious how you plan to obtain over 375hp??

I agree with Jess, this seems silly... there is nothing wrong with our suspension setups...

ive been told by a pure BMW track junky of MANY years (who is sponsered by Amsoil, AST-USA, BFGoodrich, Corbeau, Dr. Vanos, BimmerSpecialist.com, StopTech / Zeckhausen Racing, Vorshlag) that with a proper driver, the 318ti's in near stock form can hussle around a twisty track almost as quick as stock M3's... and the M3 only gets the edge on the straights.
And he has been around the block long before most of us were alive.

And like Jess said anyways, they used this setup for years in the E30's, and in highpowered Mcoupes and ZM's.. I understand the alure of the dualearred diff, but its obtainable without hacking your car up for a setup that might handle like a bag of bricks.

You may be in school to become a mechanical engineer but undertaking this will certainly butcher your car and I almost gaurentee you will end up with 2 parts cars instead of 1.

All I can say really, is that if the BMW engineers of the late 90's decided the normal e36 suspension belonged under this car, thats what we'd have. Not trying to rag on you, but this is just one of those brain-fart ideas that isn't really logically thought out, and even if you figure out the geometry behind it and do this, I bet a regular TI with a few suspension mods would run absolute circles around you....

[318tian]

i just figured the rear end touching the car at 10 points would be alot more ridgid than ours that only touches at 5 points. im not saying that it doesnt handle great. but with an s52 with a few goodies im going to be pushing a lot of tourque for this setup. ill most likely get urethane subframe bushings, camber kit, bavauto full sport kit, rear lower butt strut,e46 upper shock mounts, bigger sway bar, and maybe e30 diff or another bigger LSD preferably with two ear moints. would love a rear upper strut bar but my sub box is in the way. im going to upgrade the front also. meyle control arms with full metal ball joins, front strut bar, urethane offset CABs, camber kit, huge sway bar, maybe x-brace. not sure if its worth the money. would help protect my oil pan though i assume. i was thinking about the z3m subframe but those arent easy to come by.

[lysergicsurfer]

Most people on this forum would say that the xbrace is a much better upgrade for the money than a front strut brace. Probly one of the biggest bang for your buck upgrades you can do to these cars.

You also say you want rear shock mounts, chamber kit, and bav auto sport kit. I would recomend a full race coilover suspension, A good set should include all these upgrades, and be much better.. The bav auto sport kit would probly be softer than what your wanting I assume. Just a thought.... With the setup you are hoping for, I would want the best upgrades possible, I would certainly buy the best coilover kit I can find, instead of just finding good deals. 350hp + would be useless without a great suspension...
Oh yea save money for a really good brake system.

[cooljess76]

The M Z3 subframe isn't much stronger/better than ours! Besides that, IT'S THE SAME SEMI-TRAILING ARM DESIGN. The only benefit of using an MZ3 subframe and trailing arms would be the ability to run MZ3 rear brakes. The fact that you've considered a rear strut brace "but your subwoofer box is in the way", leads me to believe that you're a kid with mixed up priorities, lol. Trust me, there's plenty of people on this forum THAT ACTUALLY HAVE SWAPPED TI's and the Ti rearend is working just fine for them. My suggestion, work on getting that swap and HP goal met, then worry about how strong the rearend is. An e30 or equivellant LSD is a no-brainer and is absolutely necessary if you're going to do an engine swap. The small cased Ti diff simply can't handle the torque. A dual eared diff would be an awesome upgrade and there's even a kit available! However, it's not a necessity. Most of us run an e24, e28, e30, Z3, MZ3, or Mcoupe medium case diff. It's cool to have dreams, but until you actually put the thing on a dyno and make 375hp, it's just that, a dream.

[Philly]

If you bought all that and then put bavauto springs underneath it, your nuts.

If your truly serious about dialing in a good suspension, look into Bilstiens PPS9 coilovers for starters, and work your way off that.
Don't just throw a bunch of random parts at it. I don't know of anyone who have ran a rear tower bar and been happy with it.

Reading around here and other forums will give you a good insight. There is one guy here with a competitive track TI and he has quite a nice setup IIRC... the thread is here somewhere.