Bmw E36

[Aly]

Hi All,

I looking to use an E36 320i as a donor the only concern I have is the total size of the rear diff and driveshafts which will effect the size of the rear wish bones.

Does anyone know the size of the span or where to find the info and how to calculate new size of rear wishbones?

Apart from the dummy strut on the front wishbones are there any other issues/thoughts I should be aware of?

Many Thanks,

Aly

[Chris Gibbs]

I'm starting a BMW based Roadster soon, but 5 series based If you can get some dimensions and pictures of the 3-series parts to me, I'll try and help you out.

Cheers

Chris :)

[Aly]

Thanks for the offer of advice Chris but I'm at the collecting tools, scanning ebay and the local ads for a suitable doner at the moment so I'm open to change. I just don't want too much hassle when it comes to the important areas.

Found this if it helps
1988 535 Rear Track 57.501 in | 1460.5 mm.
1993 325 Rear Track 55.701 in | 1414.8 mm.

couldn't find the sierra from the same source http://www.conceptcarz.com/view/make.aspx

And you quote in another post the sierra rear track was 1460mm

So if I use a shorter rear track can I reduce the length of the wishbones to make it all fit - thus if I use a rear track of 1414.8mm the wish bones will need to be 22.6mm - 10mm (printing error) shorter than stated in the book, leaving a total shorting of the rear wish bone by 12.6mm each side.

I take it that this change wont have a detrimental affect on suspension setup.

Thanks again

Aly

[Chris Gibbs]

Small changes to the lengths of the wishbones such as this won't make much difference, although if you sort out the lengths I'll feed them into my suspension program just to be sure.

Although the differences in track are a good guide to wishbone lengths, because of the possible differences in wheel offset, it's not definative. Track is measured from the centre of the wheel and tyre, therefore the offset of the wheel affects the track. Two cars with the same track may have very different wheel mounting face dimensions

The important dimension is the wheel mounting face to wheel mounting face dimension.

Other things to consider are:-

I believe that the BMW hub is part of the rear suspension trailing arm, this will need machining or replacing to fit the Roadster type upright.

http://i126.photobucket.com/albums/p112/chrisg222/bmwhubtop.jpg

This is the E30 rear hub.

Are the calculated positions of the hub fixing bolts in relation to the upright within the area of the Plate as described for the Sierra version or will a larger plate be required?

Will the brake set up be suitable?


The ideal way to sort this would be if anyone has engineering drawings of the BMW hub or access to the parts for accurate measurement.

Cheers

Chris

[Aly]

Okay I'm going to stop right there down the BMW route. By the book it is with a DOHC model get the SVA'd and then treat it to an Alfa V6 and some Emerald engine management.

Thanks for your above effort Chris but it's starting to look to hard for my first from scratch, there is always the next one...

[Theoldman]

I found this site for vehicle specifications. It might help if someone is looking at different donor vehicles. http://www.carfolio.com/specifications/

[JonBowden]

Creating designs for using BMW parts could be worthwhile. I haven't seen a Sierra on the road for months (and I have been looking out). By the time I get a garage and can start building, there just won't be any.

[Mike400]

Like Chris has said before, (and in the book) there are still around 75000 sierras on Britains roads, that doesnt include the ones lying around peoples gardens etc etc

Kit car building might be popular, but its certainly not popular enough to use up the current supply anytime soon.

But I think that kit car manufacturers, and indeed home builders, should be looking more and more at the likes of BMW models for use in their kits.

Lets face it, the sierra is a very old design nowadays.

For the same price as a tidy sierra donor, you could easily pick up an E36 3 series saloon, or a similar aged 5 series saloon, which will have bullet proof mechanicals, more sophisticated engine, better brakes etc etc etc.

The 1.6 and 1.8 4cyl engines would probably be an easy fit, but some chassis modification or re-design would certainly be required for any of the larger capacity engines, as they are 6 cyl jobbies and a bit longer. But a roadster with a bmw 2.5 straight six, producing 170 bhp, would be a lot of fun methinks!

Only thing is, with more sophisticated engine, comes more electronics.....

[cryoman1965]

The 1.6 and 1.8 4cyl engines would probably be an easy fit, but some chassis modification or re-design would certainly be required for any of the larger capacity engines, as they are 6 cyl jobbies and a bit longer. But a roadster with a bmw 2.5 straight six, producing 170 bhp, would be a lot of fun methinks!

Only thing is, with more sophisticated engine, comes more electronics.....

You could dump the donors ecu and injection system as there probably wont fit under the bonnet of a seven. Instead fit a Mega jolt and bike carbs, even to the straight 6. Carbs can be respaced and extra carbs added to fit the application.:D :D

Nige

[bobbyh]

can you get the half shafes shortend whould thay make it fit (i'm going donw the bmw rout)

[racebreed]

i think its a case of measuring the engine in the e36 and seeing exactly the space required im using the 325 lump in mine.

Chris's brother in law i think is putting a 525 engine in a roadster hopefully more information will come soon

[bobbyh]

is it the same age 5 sires cuz i think its the same engin in them ??

[racebreed]

yes its the same m50 engine

[bobbyh]

get the m52 its lighter alloy block 1995 on i think

[Salona]

Hi Chris, I was wondering if you built a 5 series based roadster and if so, could you give me some advice. I have ordered the steel for the chassis and I have a 1993 518i waiting to be stripped in the drive.

[thane]

surely it is possible to just modify the chassis in order to just accept the engine and transmission, possibly have a custom prob made up and mate to sierra diff. and normal suspension?

If you do go to the lengths o using as much from a BMW as pos, then I think that is no mean feat but will require alot of time and effort and drawing board time.

As I've said in another post about donors, sierras are getting thin on the ground to find in some places and not others, but BMWs and co do appear to be in more plentiful supply, but are the tuning options as competitive as all the ford ones?

Would be interested to see what the differences are and adv/disadvantages are of a BMW build... would see a new book or a supplement to loval readers should they fancy a go Chris?

[Chris Gibbs]

Hello Salona,

I've helped with BMW 5 series Roadster which you can see here

http://www.haynes.co.uk/forums/showthread.php?t=119

As you can see this car was made much wider to fit the 2.5 straight six but the four cylinder engines will fit in the standard chassis, the gear box would require modification to the chassis, similar to the MT75 mods here

http://www.haynes.co.uk/forums/showthread.php?t=53

The front and rear hubs are substantialy different to the Sierra set up.

The fronts require a fabrication like this

http://i126.photobucket.com/albums/p...ntupright4.jpg
This would bolt to the fixings for the front strut

I haven't done any analysis on geometry yet, it may be some time as I'm right in the middle of a new book.

At the rear the rear hubs bearings are part of the huge and unusable trailing arm, I think ther best way to deal with this would be to make (or have made) a bearing carrier to receive the hubs which would bolt to the rear upright like the Sierra.

I'd ask on the forum too, I know some builders are using BMW bits and might have some more practical advice for you.

If you need anything else don't hesitate to get in touch, I'm here most days

Cheers

Chris