Preparing an e21 for Track/Light Racing

[dlguadiz]

This is going to be partial a build-thread, partial technical discussion on how to ready this car...

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to join these races...

Race Pic 01.jpg Race Pic 02.jpg

It is going to be the only e21 to be racing locally, so I want to make a good impression. There is an e46 M3, e30 M3, and modified e34. I've done some homework and have an idea what needs to be done so I wont rehash those here, but would certainly appreciate any ideas the collective minds here can come up with. I also have budget concerns so its going to be tight.

This is the plan so far, most have been sourced already:

(1) e28 Rear subframe with e34 Trailing Arm, stock brakes with 300x10 rotors, 38mm piston cylinder
(2) Rear e34 or e39 Koni Yellow with GC Coilover sleeves, spring is rated at 500 lbs/in
(3) Front GC coilover sleeve with 360 lbs/in spring
(4) Front wheel is a BBS RS Style 5 from an e34 (et20 15x7J), 205/55/15
(5) Rear wheel is a BMW Widened Steel Rims (16" unsure of width and et), 235/50/16
(6) e36 Medium Case Differential, Target is 2.93 to 3.25 LSD
(7) I have an m20b27 engine, already bought 885 head and Motronic 1.3 etc.
(8) Will turbo #7, already have 2.75" exhaust pipes
(9) 5-speed Getrag Manual

I am still deciding:

Front Suspension--
(1) use e36? I already have an e36 subframe, spindle and hub -- probably make an e36/e30 hybrid shocks so I have the option of changing the inserts
(2) instead of an e36, use e34 fronts??
(3) instead of an e36, use e30 fronts??
(4) use e21 subframe but upgrade to Mcintyre type suspension

Brakes--
(1) use e46 330i upgrade -- but this will have a problem with my 15" wheel...
(2) I got offered an e36 M3 96+ spindle, hub, and rotor -- might also be a problem with the 15" wheel
(3) can a front 300mm rotor from an e46 325i work? worried about brake bias

Power and Drivetrain--
(1) I also have an m30 and can turbo it, but it might be too much of a pita to maintain
(2) Large case LSDs? They are so much easier to source here than a medium case LSDs

Those are the things that keep me awake at night... same things that make me excited about the future...

[dlguadiz]

I really do not mind about tires sticking out of the wheel wells... I want a wide track as much as possible... maybe aim for wider front than rear for better cornering...

[dlguadiz]

Bought these quality but reasonably priced stainless steel brake lines for half the price of bmws'. Its for a volkswagen but the specifications line up with the e21/e30/e36/e34 brake lines as follows:

e21 Brake Hose Front, 34321159879, 290-314mm, m10x1, Female/Female
e30 Brake Hose Front, 34321159890, 300-330mm, m10x1, Male/Female, VW355mm (Disc Brakes)
e36 Brake Hose Front, 34321159717, 425-455mm, m10x1, Male/Female, VW480mm (Drum Brakes)
e21/e30/e34 Brake Hose Rear-Chassis, 34321159878, 222mm, m10x1, Female/Female, VW277mm
e30/e34 Brake Hose Rear, 34321159881, 200-235mm, m10x1, Male/Female, VW246mm

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[dlguadiz]

I got a hold of this e36 188 3.15 Open Diff. It will be converted into an LSD. The conversion kit manufacturer recommends that the resulting LSD should only be used for the streets but I am going to use it for track purposes. I am not going to make skid marks or do burnouts -- I just need more traction on corners. Anyway, I can always buy a true race LSD internal if this fails.

myE36 Differential 003.jpg

myE36 Differential 001.jpg

Edit: After watching several of their videos, I am convinced RacingDiffs' conversion set is the best option out there.