Compact tarmac rally car

[E30-323ti 66]

Thinking about it, I was comparing to E30 arms, I didn't realise the compact had a wider track. The MZ3 also has different brake caliper mountings that will take the big M3 calipers.

Sorry for dragging OT.

'Track' isn't wider, as the stock wheels are 15x7" et47.

To late in the day to do the maths on that.

Hub flange to Hub flange, MZ3 < ti/Z3 < Z3 (6cyl)

Also sticking with readily available compact TA's means it is cheaper to have a stack of them in the service vehicle.

They are almost an expendable component, and can be swapped out very quickly (esp. if you ditch the cable handbrake).

Edited April 26, 2011 by E30-323ti

[Steve K-B 51]

Thanks for the info so far, have to sort it out sooner or later.

Not a lot to update, have been busy and have only really been attacking that bloody seam sealer. Fun fun I like the clean look and had planed to seam weld the whole car but after the bitch of a job removing most of the sealer inside im not really wanting to attack the bottom half!

Wont get much done this weekend either due to family comitments.

Here are the goods I have:

[SUSPENSION 0]

Check out www.racecarsforsale.net theres heaps of compact rally cars on there for sale, might give you some good ideas

[hybrid 1043]

Barry, Steve

I was thinking a little bit more after your phone call about the m-coupe trailing arms.

You can always extend the trailing arm track by moving the swing arm points which are going to need up rating anyways. This will give you the 15-20cm more track each arm you're after. You'll likely need to uprate the 318 halfshafts anyways so I would suggest getting a set of custom shafts or from a 540/x5 and machined hub splines and diff flange splines needed for rally demands (common failure points in BMW drive train under loads).

You would also need to increase the front track as well and move the towers mount points outward, however doing some homework around ackerman angles and etc. This would fill those flared gaurds quite nicely.

[conrod 1]

This will give you the 15-20cm more track each arm you're after.

15-20cm?? Are you serious???

[hybrid 1043]

15-20cm?? Are you serious???

Yea, If he wants wide body like this.

Just running low wheel offsets wont really cut it on a rally car as gravel tires are skinny.

[westy 614]

Think you'll need a bigger wide body than that Josh ha.

Steve, for front track increase look at using E46 lower arms?

[E30-323ti 66]

...extend the trailing arm track by moving the swing arm points which are going to need up rating anyways. This will give you the 15-20cm more track each arm you're after...

I gather you mean where they are attached to the rear subframe?

To get +15-20cm per side, the outer trailing arm mounts will need to be outboard of the rear subframe mount. sounds f'd too me.

Having been involved in a fair bit of rallying, the best thing you can do, is use as near as possible to stock components for expendable items like suspension arms, tie-rod etc... as they tend to get used, and if they don't, you're not trying hard enough!! (unless you have plenty of $$ to have a stack or prefabricated parts available).

Even a rear sub-frame should be in your spare parts, as they are known to bend given a decent whack.

[hybrid 1043]

I gather you mean where they are attached to the rear subframe?

To get +15-20cm per side, the outer trailing arm mounts will need to be outboard of the rear subframe mount. sounds f'd too me.

Hmmm just looking at glenn's subfram pics .. it doesnt even look like its possible to move them at all on the current subframe setup.

I like westies idea of running e46 gear and e46 rear pan cut may as well do what hes done with his e30. That way you can still use stock parts.

[E30-323ti 66]

I wouldn't consider an E36/46 multi link rear for a rally car, lateral links are too flimsy as they are designed to fail to save other critical components like the sub-frame.

If I were to move away from the semi-trailing arms, I would be heading towards a lateral A-arm / Strut setup for simplicity (easy to fabricate, tune & replace components).

Most tarmac/gravel rally's at the level being entered, isn't won by the flashiest chassis suspension, it's the driver who is prepared to put the most on the line, as there is bugger all prize money, sponsorship or kudo's for winning, it's a personal thing. IMHO anyway.

[westy 614]

Lol. I was only talking about the front.

[Apex 693]

Having been involved in a fair bit of rallying, the best thing you can do, is use as near as possible to stock components for expendable items like suspension arms, tie-rod etc... as they tend to get used, and if they don't, you're not trying hard enough!! (unless you have plenty of $$ to have a stack or prefabricated parts available).

Even a rear sub-frame should be in your spare parts, as they are known to bend given a decent whack.

This. I know of one E36 running at the pointier end of Targa that has bent a few rear ends and left the mechanics doing repairs with a sledge hammer in service and replacing the sub frame overnight... twice in one Targa. They are not very tough.

I wouldn't consider an E36/46 multi link rear for a rally car, lateral links are too flimsy as they are designed to fail to save other critical components like the sub-frame.

If I were to move away from the semi-trailing arms, I would be heading towards a lateral A-arm / Strut setup for simplicity (easy to fabricate, tune & replace components).

Most tarmac/gravel rally's at the level being entered, isn't won by the flashiest chassis suspension, it's the driver who is prepared to put the most on the line, as there is bugger all prize money, sponsorship or kudo's for winning, it's a personal thing. IMHO anyway.

I cant say too much about the set up in said E36, they have spent a long time and many Targa's getting it tough enough with enough travel but it may be worth poking your head under a few E36's on Targa to see what they have done to increase strength and lessen the fatigue rate, there are some key alterations to make the back end fast road friendly, you don't want something breaking at 185kph over a blind crest.

As said it comes down to how hard you can push it with complete disregard for the vehicle, of course a $250,000 Nissan GTR and a bit of experience also helps

Edited April 29, 2011 by Apex

[*Glenn* 854]

This. I know of one E36 running at the pointier end of Targa that has bent a few rear ends and left the mechanics doing repairs with a sledge hammer in service and replacing the sub frame overnight... twice in one Targa. They are not very tough.

I cant say too much about the set up in said E36, they have spent a long time and many Targa's getting it tough enough with enough travel but it may be worth poking your head under a few E36's on Targa to see what they have done to increase strength and lessen the fatigue rate, there are some key alterations to make the back end fast road friendly, you don't want something breaking at 185kph over a blind crest.

As said it comes down to how hard you can push it with complete disregard for the vehicle, of course a $250,000 Nissan GTR and a bit of experience also helps

An E36 4 door or coupe is completely different in the rear suspension to an E36 Compact Graham. Poking around under 4 doors & coupes will result in nothing gained. E36 Compacts, Z3's & E30's share the same rear suspension configuration.

[Apex 693]

Sorry, yea I quoted that quite poorly, Im aware they are different, it was more in response to if he was to move to a multi link setup I could result in a few ideas gained.

Either way I agree with E30-323TI that a OEM+ setup using easily replaceable parts would be a good move, going custom or using rare parts could and likely will have you going home early. Im glad my car has a simple rear suspension set up and is reliable and strong.

Going all custom makes the car very hard to setup on the spot and if you need a quick replacement of an aftermarket part you may be sh*t out of luck.

[Steve K-B 51]

I agree with keeping things stock if its possable.

Good idea on the e46 lower arms, it looks like it should push the bottom out by 35mm, altho im not to sure what im going to do with the strut tops yet.

That Harry Hockly kit isnt as wide as it looks (1750mm from memory) but im still waiting to hear back from another company so hope to have the kit sorted in a week or so.

Some one mentioned gravel tyres? I wont be running on gravel so no problem there.

I got a bit bored of seam sealer removal today and decided to try the GTR's front guards etc on the car.... To wide??

Also removed all the intrusion bars, the curved ones were in the rear connected to the B piller, jacking point in the sill and rear wheel arch. My only guess is its there for the rear passenger/s in case of a side impact and also to help with strengthing the jacking point. I may need to add some gussets as I still intend on using the jacking point but it was just to damn heavy to leave it in as it was. They dont look like it but they are

heavy!!!

Edited May 7, 2011 by Steve K-B

[hybrid 1043]

If its only for tarmac, the e46 gear should server well Pushing the towers out should be fairly easy to do. So it will be more for targa/hillclimbs ?

[Steve K-B 51]

Yup, any tarmac clubsport events, Taranaki tarmac rally and if possible id love to do a Targa event.

If I can help it I dont want to go to the trouble of fabricating or a major retro fit of the rear suspension and hope to keep the swing arm set up. Whos E30 is that btw?

Cheers

[hybrid 1043]

Cool, the e30 with the e46 suspension ? Thats tony's (Westy)

Here is the build thread.

http://www.bimmersport.co.nz/forums/index....showtopic=23929

And here is a video run around I've done of it. You can see the underneath of the floor pan cut and replace

[E36ShoppingTrolley 7]

Check out www.racecarsforsale.net theres heaps of compact rally cars on there for sale, might give you some good ideas

heres a great idea haha sweet bodykit

[SUSPENSION 0]

[Steve K-B 51]

Update, No photos yet sorry.

Have sorted the flares and the rest of the kit so will be getting the extract same kit in my first post. I was keen on a kit from the Netherlands but the language barrier was to much hassle. Wont be here for aprox six-seven weeks.....

The main hoop and two front bars have been done but im not to happy with them so it may have to be redone.

Most if not all the seam sealer on the top side is done but have decided to leave the bottom half as its such a bitch to get off.

Next part is to see where and how to mount the floor mounted pedal box, I managed to thief one from my old mans as he is replacing his. Problem is it will have to sit quite far back from the fire wall as the cylinders hang off the back by about 100 mm. A fire wall mounted set up would be ideal but as ive got a free one im super keen to use it if I can! I'm quite tall so my seat is going tom have to go back further in the car, unfortunately I think the main hoop is in the way. I wanted it angled backwards to create more room but it hasn't been made how I wanted it.

I have decided on Sparco seats with the drivers side either being a Corsa or an Evo 2 plus. Im a skinny lanky bastard and they seam to fit me nicely. Also I plan on using a Hans device so I needed the belt holes in the right location. They wont be in the country for at least another six weeks.... Id really like to get it earlier as I want to dummy up the pedals, and seat with the cage in. Ahh

[Steve K-B 51]

Its been a good week!

Thanks to Targa passing and putting the off road racing prep ive been involved with on the back burner I got to spend the weekend in the shed.

Engine is in!! Was expecting the rear gearbox mounts to be completely wrong with the M52 but turns out they bolted up to some unused mounting holes, Score! The gear stick even comes out of the tunnel at the right place so no cutting required. Also I thought the power steering system wasn't going to mount up but again but BMW are a pack of geniuses! The M52 unit bolts up to the engine and compact steering rack perfectly. Altho I do plan on using a Z3 rack so this may turn out differently.... we will see. I Just have to pack up the engine mounts a tad and drop the sway bar a little to help with a small clearence issue.

Im keeping the cage but cant use the floor mounted pedal box. Not cool and not sure if I will even use a pedal box at the moment. A lot of money. Have got a sparco seat, have made up my own alloy seat brackets as the sparco ones are over $200. I made a set for less than $30. Will need to chop into the tunnel to get the seat more central as its about four inches off the steering wheel center line. Quite a bit so may even have to move the wheel towards the outside of the car. stink

Still cant find the camera but will have some photos in the weekend.

[moe 31]

Its been a good week!

Thanks to Targa passing and putting the off road racing prep ive been involved with on the back burner I got to spend the weekend in the shed.

Engine is in!! Was expecting the rear gearbox mounts to be completely wrong with the M52 but turns out they bolted up to some unused mounting holes, Score! The gear stick even comes out of the tunnel at the right place so no cutting required. Also I thought the power steering system wasn't going to mount up but again but BMW are a pack of geniuses! The M52 unit bolts up to the engine and compact steering rack perfectly. Altho I do plan on using a Z3 rack so this may turn out differently.... we will see. I Just have to pack up the engine mounts a tad and drop the sway bar a little to help with a small clearence issue.

Im keeping the cage but cant use the floor mounted pedal box. Not cool and not sure if I will even use a pedal box at the moment. A lot of money. Have got a sparco seat, have made up my own alloy seat brackets as the sparco ones are over $200. I made a set for less than $30. Will need to chop into the tunnel to get the seat more central as its about four inches off the steering wheel center line. Quite a bit so may even have to move the wheel towards the outside of the car. stink

Still cant find the camera but will have some photos in the weekend.

do you still have the 4 cyl sway bar in the car? if so change to 6 cyl type they have a deeper bend in them and you wont need to raise your engine,keep eng as low as possible,6 cyl will bolt straight in

[Steve K-B 51]

Good to know, thanks Michael and ill look into it.

This forum is quite helpfull!

[Steve K-B 51]

Have some photos:

Engine in car with out intake

Seat brackets

Seat to close to tunel. Will have to chop into it, think I can get about 40mm by doing this. Not quite enough for my liking but its better than nothing.

Gear box selector all mounted up in the correct location. Also floor panel mocked up.