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BMW E36 Compact Budget Build

Posted by Nate.Vincent 
Nate.Vincent
Nate Vincent
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BMW E36 Compact Budget Build
August 17, 2015 03:41PM
Hello,

First, let me say that this will be built on a tight budget with smart thinking out weighing money spending.

Second, this may take some time. Yes deadlines are nice and I would love to be out on stage in 2016. That said, I have 14 month old twins (boy and girl) and I work a lot. Yes, I do stay up all hours trying to make progress but sometime I just plain old can't. My time isn't always my time

The stuff you may actually care about:

I'm building a E36 compact or 318ti as they are often referred to state side. The car had a destroyed motor so picked up a 328i for a bargain and pulled the drive train and other useful spares (extra suspension, steering rack, better brakes).

I have started on the cage and have the main hoop and half laterals completed. Now it's a matter of connecting the dots... a lot of dots. That said, before I do I want to post some build pictures and let them be discussed. It would be much easier to make adjustments now then after everything is welded into place. I've looked through Dave's build and many other from around the world and think I have a good idea of the best way to build this car but I'm sure there is many things I haven't considered.

Here is the basic plan outlined:

-M52 2.8 (iron block) Maybe switch to aluminum when this one dies. I'm not concerned in the least about power...I planned on using a four cylinder but they are less common stateside and hence more expensive.
-Standard gearbox with a 4:10 or 3:73 188mm LSD (first gear will be for loading the car on a trailer only).
-Bilstein suspension (figuring the Sierras and Grp. A escorts had similar weights and suspension geometry).
-Extended rear shock mount to mount standard 10" travel damper (may have to shorten damper stroke sightly).
-328i vented discs and boosterless hydraulic system using modified standard pedals with a bias bar.
-The rest is basic rally car prep.

Here are some pictures:



Black outline where the 1/8" footing will be.




Diff/subframe mount that the cage will pick up on.




I sketched in red the door, sill, and dash bar planned locations.


Again some more sketching of door, sill, dash, roof, harness, A pillar, and front strut bars.


This one may be a bit confusing but it shows the whole cage layout as I see it in my head.



Now... experienced rallyist and scrutineers please let me know what you think.

I will hopefully have the rear turrets designed and fabricated soon and be able to start connecting the cage to them.
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NoCoast
Grant Hughes
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Re: BMW E36 Compact Budget Build
August 17, 2015 06:52PM
I like cage feet on boxes. Plan sounds good otherwise.



Grant Hughes
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Denver, CO
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tdrrally
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Re: BMW E36 Compact Budget Build
August 17, 2015 07:35PM
what about main hoop feet on a tube that runs left to right?



I would rather drive a slow car fast as a fast car slow!
first rule of cars: get what makes you happy, your the one paying for it!
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alkun
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Re: BMW E36 Compact Budget Build
August 17, 2015 08:10PM
door bar x looks too high, put the top of the tube on the main hoop at the height of the door latch.


otherwise, looks like an awesome driveway project (my favorite kind of rally car build)
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john vanlandingham
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Re: BMW E36 Compact Budget Build
August 17, 2015 09:01PM
Quote
NoCoast
I like cage feet on boxes. Plan sounds good otherwise.

Second emphatically this..I do a spreader plate on the floor.Unlike most of the chillins here I want sumpin under the edge of the box but you make the boxes and jut tack the lid down and the box itself while fitting then hammer it loose to drop the whole cage assembly down (however tall ya made it) so's you can weld the part of the tube that would be against the roof and inaccessible..Then lift whole cage up, hammer boxes back the feet of the main hoop..under and zap zap.

Also yeah lower the door bars, we jump in and outta rally cars a lot..the door bars is a optimistic attempt to keep trees out..To whatever degrees they might keep a tree out, they'll do that a lot lower just fine..Likewise take out evermm you can on the so called Toyota bars to make the hole you jump in and out of as large as possible..
Same for the so called Cossie bars 9main hoop to forward half laterals above the door.



John Vanlandingham
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modernbeat
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Re: BMW E36 Compact Budget Build
August 17, 2015 09:11PM
Why people like the Compact rather than the standard E36 I can not fathom. It's got the crappy E30 rear suspension and tiny diff rather than the fairly good E36 rear suspension. Must be the same reason people like metalic brown diesel, manual Volvo wagons. They like to be weird.



Jason McDaniel
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john vanlandingham
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Re: BMW E36 Compact Budget Build
August 17, 2015 11:02PM
Quote
modernbeat
Why people like the Compact rather than the standard E36 I can not fathom. It's got the crappy E30 rear suspension and tiny diff rather than the fairly good E36 rear suspension. Must be the same reason people like metalic brown diesel, manual Volvo wagons. They like to be weird.

Maybe they like the suspension in the rear that doesn't routinely break off the cast iron lower shock mount..Maybe. but I'd be guessing there.



John Vanlandingham
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Nate.Vincent
Nate Vincent
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Re: BMW E36 Compact Budget Build
August 18, 2015 07:56AM
Quote
john vanlandingham
Quote
modernbeat
Why people like the Compact rather than the standard E36 I can not fathom. It's got the crappy E30 rear suspension and tiny diff rather than the fairly good E36 rear suspension. Must be the same reason people like metalic brown diesel, manual Volvo wagons. They like to be weird.

Maybe they like the suspension in the rear that doesn't routinely break off the cast iron lower shock mount..Maybe. but I'd be guessing there.

Yes john is right... The trailing arm on a e36 is a massive compromise. It wraps around the wheel and mounts in the rocker panel. I can only assume this was done to give room for the fuel tank and rear seat. It bends all sorts of ways and is quite brittle. Also BMW seems to have a love affair with mounting dampers in single shear.

There are a couple other reason I choose a compact over a standard E36. That said I do not disagree that the later multilink suspension is better at making a car go around a corner and keeping the wheels at the angle that would be optimal.

First, driver impressions. I have owned and driven all of them. For some reason e30s and e36 compacts have what I think is a much nicer and more controllable over steer characteristics. They definitely can't get as much lateral grip but they loose grip and gain grip in a very consistent way.

Second, They are simpler and cheaper. The standard E36 has 15 bushings/bearings in the rear suspension, whereas the E30 has seven. For standard BMW bushings to rebush the standard e36 is upwards or $750 while the E30 is under $200.



VS



Third, Interchangeability. I have an E30 M3 and a handful of LSD differentials, they are all interchangeable. Also a a good friend and neighbor has a E30 rally car with a garage full of spares. It only made sense.

Last, Weight. Dave built his rally car and really didn't do too much in regards to weight reduction (still had steel panels and all glass). The car weighed roughly 2650. Brakim with their composite panels and lexan windows weighed there car and it came in at 3200. That's a pretty big delta. I can't say I know exactly what spares what not each car had but either way that is significant.

But in all honesty... if at the time I bought this car a similarly priced E36 325/328 was available this post might have never happened.



Edited 1 time(s). Last edit at 08/18/2015 01:18PM by Nate.Vincent.
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Nate.Vincent
Nate Vincent
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Re: BMW E36 Compact Budget Build
August 18, 2015 08:55AM
Back on task. I did some searching on the interwebs to see how boxing in the feet would be best handled on this specific car. I found a few pictures of a F2000 compact that used rear boxed. Because the car has massively high rockers it makes this a little different then most. Here is my sketch followed by the F2000 car.





Another question I have is would something like this be legal?





I can't find much for information on it. I would only do it if the tube terminates on the dash bar junction. I don't like to see them terminate on the middle of the dash bar (I get a bad feeling about that).


Here are some pictures of what I'm planning on the rear turrets.





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NoCoast
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Re: BMW E36 Compact Budget Build
August 18, 2015 11:03AM
Compact - Weldable trailing arm, possibly stronger components.
Diffs are all easy and interchange without much trouble.
Dimensionally the Compact and Sedan are the same, the Compact has 1 foot less overhang. To someone like John Lane, 1 foot probably coulda saved him a few times maybe. smiling smiley

I like the look of the Compact the best, once you get the proper rear wing. Based on my previous like of the Merkur, I suppose this must be an issue. I like two door rally cars, Coupe models catch a premium for some ungodly reason around here. I can buy a 4 door for around a grand all day but finding a two door under 3 is trickier. Compacts are a mix of two, you can find the 1k car but the 2.5-3k ones are more common.

Find Ted Atencio's build on facebook that we did in his Compact for some good pictures.



Grant Hughes
http://rally.build
Denver, CO
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DaveK
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Re: BMW E36 Compact Budget Build
August 18, 2015 01:03PM
Couple other reasons I like the compact:

Roof height - in the 328 coupe I have that Jari built, my head's pretty close to the roof bars, but in the compact I've got loads of clearance.

Captive windows - lexan windows are a snap if you ever wanted to go down that path. Reason I dislike the non-captive ones on the coupes is that old BMWs have wiring issues, and if you put the windows up while the door is open they can over extend. So if you have someone who isn't paying attention you can shatter them if you don't notice when you go to close the door.

Agree with Jason that the E36 rear end design is superior for adjustability and general track day useage, but we've seen plenty of rear lower shock mount failures given the small sample size of M3s running around the US. Fixing that issue is an easier task on the E30 RTA design.

I'm still unsure how the hell Brandenburg's M3 is so heavy. With the new reinforcements to the supra diff mounts, mine is probably about 2700 lbs wet, maybe more now as I think the S54 is heavier than the S50. That does not include spare wheel/tire, tool kit, jack, or light bar, so probably pretty safe to assume that would add an extra 100 lbs.


In regards to the question about the X bar going through the dash out to the shock towers. I wanted to run stuff out to the shock towers, but ended up skipping that as it would've made retaining the OEM wiring very difficult (main fuse box and ECU compartment are in the way), would've made keeping the windshield blower more difficult. Going with an X like pictured on the Cossie would really make some engine work hard/impossible given how far back BMW stuffs those long 6s.

Dave



Edited 2 time(s). Last edit at 08/18/2015 01:13PM by DaveK.
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NoCoast
Grant Hughes
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Re: BMW E36 Compact Budget Build
August 18, 2015 04:49PM
Wait! Why are there two shock towers in the passenger side? Creepy!!!

I typically do not ever go forward to the shock towers. Plate the tops to strengthen but I like to have that extra bit of crumple zone. If you have to reshell, you reshell. We aren't racing a $32,000 STI so we can buy a new shell and cage it for pretty cheap. Just my opinion though.

Turns out I don't have any good pics of what we do on main hoop in E36 cars but here's an E30, pretty much same idea.



Grant Hughes
http://rally.build
Denver, CO
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Nate.Vincent
Nate Vincent
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Re: BMW E36 Compact Budget Build
October 09, 2015 10:41AM
Been a while since I have updated this... have some more pictures and a bunch more questions.

First here is the main hoop set up with a box style mount.



The front over hang on the top plate will be trimmed and I also plane to spread the load on the floor with some plate before the boxes are fully welded in place.

Here is the main hoop positioned on the box.



Worked out some rear suspension travel stuff.





I plan on running 10" travel Bilsteins with the travel spaced down to around 9". I will reinforce the trailing arms and run a true coil over system. I'm thinking about building this extended turret by creating the mounts with the cage, then tying the sheet metal on the car to the cage mount/turret top. I think it might be easier this way to maintain decent geometry and would allow me to bridge the gap rather than make a standalone turret.

Now a couple of questions:

First hence the title this is a budget build. How do you all feel about using ERW tube for front strut reinforcements, rear shock tower cross bar, any other suspension tie in that may not be directly related to the "FIA safety cage". The stuff is half the price of DOM and in my opinion about 98% the quality.

Where is the best place to get Bimarco Grip seats.

Who do you use for -3 flex brake line for whole car plumbing. I also need metric conversions for calipers.

Steering quickener or not....?
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DaveK
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Re: BMW E36 Compact Budget Build
October 09, 2015 10:53AM
Quote
Nate.Vincent
First hence the title this is a budget build. How do you all feel about using ERW tube for front strut reinforcements, rear shock tower cross bar, any other suspension tie in that may not be directly related to the "FIA safety cage". The stuff is half the price of DOM and in my opinion about 98% the quality.

I wouldn't. Use the same stuff for the whole cage. I didn't have a rear shock tower bar that connected the two tops. Not sure why it'd be needed, plus it would eat up valuable space for spare tire.


Quote
Nate.Vincent
Where is the best place to get Bimarco Grip seats.

I think Grant carries those at www.rallybuild.com


Quote
Nate.Vincent
Who do you use for -3 flex brake line for whole car plumbing. I also need metric conversions for calipers.

I ordered mine from www.HRPworld.com. Some of the caliper fittings/adapters I had to source at local roundy-round shops.


Quote
Nate.Vincent
Steering quickener or not....?

Not necessary. Find a Z3 (non M) steering rack and call it good. I found mine from a rear crash car for $100 and the JY guys even pulled it for me. Remember, steer this car with the throttle, not fistfulls of steering wheel. smiling smiley


Dave



Edited 1 time(s). Last edit at 10/09/2015 10:54AM by DaveK.
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NoCoast
Grant Hughes
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Re: BMW E36 Compact Budget Build
October 09, 2015 01:58PM
What Dave said regarding Bimarco Grips. Though they will be drop shipped to you from Poland so 4-6 weeks delivery.
You are talking about tens of dollars in savings for those bars. I would do them all in DOM personally. I've thought about buying some ERW to use for mock up but decided the chance of accidently using it (or someone else) on an important bar wasn't worth the cost savings.

What Dave said regarding everything else.

What did you find total available travel to be? Was the compression until the arm hit the body/subframe or tire hit wheel well?



Grant Hughes
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Denver, CO
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