Track Day Maintenance/Prep

[Sterndotstern]

Hi all! I'm a new ti owner and so far I have been utterly charmed by the combination of short gears, quick revs, and willing handling. After taking a multi-year hiatus from the race track, I'm feeling the itch again. I am not a novice driver and I consider safety and reliability the top two "performance upgrades" for the race track.

That said, my car needs to catch up on maintenance. Assuming you had no maintenance records for a car, what is the minimal subset of repairs/upgrades/maintenance to consider a car safe and reliable at 10/10ths driving. I would prefer to have most of these installed for me as I do not have a lift or press at home, but I've done a lot of DIY work on past cars. If there are any "while you're in there, might as well..." items I'm very much open to suggestions. For instance, it seems that upgrading to an E30 LSD diff would make sense to do at the same time as doing the subframe/diff bushings.

For the chassis, I would expect that most of the rubber on the car would need replacement at this point (the car is a '98):
Suspension Parts
- rear shock mounts -- 33-52-1-092-362 -- $35
- front control arm bushings (pre-pressed) -- 31-12-1-136-531 and -532 -- $70
- rear subframe bushings -- 33-31-1-090-946 -- $25
- rear control arm bushings? Worth the hassle? -- $20
- differential mount bushings? -- 33-17-1-134-871 -- $20

Suspension Total: $170 + labor

The prices come from online retailers for OEM-equivalent parts.

I'm interested in the differences between urethane/delrin and rubber bushings as well, if anyone has direct street and track experience with both. Is the added expense worth it?

The plastic in the cooling system, like all BMWs, seems to be a weak point. On the M44, I understand there are some very tricky coolant passages to be replaced. Hopefully this is a complete list of what should be replaced to avoid any cooling system failures on track.
Cooling System Parts
- Water Connector (back of the head) -- 11-53-1-743-679 -- $7
- Water Pipe (not a bong) -- 11-53-1-714-738 -- $17
- Thermostat & Housing -- 11-53-1-743-017 -- $51
- Water Pump -- 11-51-0-393-338 -- $48
- Radiator -- 17-11-1-728-907 -- $171
- Accessory Belts -- 11-28-1-437-369 & 11-28-1-743-193 -- $31
- Hoses & Clamps: $60 or so
11-53-1-247-261 -- $11
11-53-1-247-398 -- $11
11-53-1-743-295 -- $17
11-53-1-743-535 -- $17

Cooling System Total: $214 plus Radiator (optional)

Those are the two main areas of concern for me. Anything else I'm missing or should consider?

Edit: based on the feedback below, my shopping list has grown to include a few more pieces.

Misc
- Engine Mounts -- 11-81-1-141-377 -- $102
- Transmission Mounts -- 22-31-6-771-220 - $24
- Fuel Filter -- 13-32-1-740-985 -- $15

Misc Total: $141
This is really good feeback. Thanks guys!

[1996 328ti]

I'd also do tranny and motor mounts as well as brake pads and fluid.

And I'm kinda torn between stock and polyurethane.
One better than the other? IDK.
They just handle differently.

[30yrMbr]

Regarding delrin vs stock(rubber) bushings, first question to answer is:
Is this going to be a dual use car? 90% track & 10% street (getting to the track) or 10% track and 90% street or some other mix. Is this your only transportation and thus Daily Driver, or is this going to be the track, nice weather and occasional use car?

Answers to those questions will alter the answer to your question. Delrin and similar bushings are less compliant than the stock or rubber bushings, thus if you want to drive it on the street, consider the harshness and noise parameters - delrin will likely be both harder and squeakier than rubber.

Those considerations will apply to street vs sport vs race shocks, struts and springs. Also, with a numerically larger diff, the revs at highway speeds might make highway driving less happy.

Lots of choices, I'll bet every one has been thoroughly explored in postings here.

Welcome to the Ti group, hope you enjoy.

[mohaughn]

If it is dual purpose, and you like the quality of the ride, go with stock OE. Otherwise, if you don't mind the vibration and added noised of urethane go with those. I've noticed that things like the rear urethane trailing arm bushing will grind down and need to be replaced probably faster than stock parts. All in all, urethane for me has seemed to need more frequent replacement in any use where there is twisting or rotation of the parts. Subframe bushings are a once and done kind of thing, but the other bushings on my car have already been replaced after two or three years of track abuse.

The labor on the rear bushings is going to be pricey, not a difficult job, just a lot of work. If you are going to do the rear subframe, do the differential and trailing arms as well. Might as well since you need to take it all down anyway for the subframe.

I'd do everything there except maybe the radiator. Buy one, and keep it with you, but if the current one is not cracked, why throw it away?

Change all your fluids, fuel filter, oil filter, check your power steering pump and lines to see if those are leaking/seeping fluid. Check the belts, and you should be fine. Spare fuel pump and fuel hose is always nice to have on an older car.

Make sure to keep any of the parts you replace that are not broken as spares. May not be good enough to get you back on track, but they can be swapped to get a car home without towing.

[Sterndotstern]

Thanks for the thoughtful responses, I updated the list above. Based on the feedback here, I'm going to plan to stick with rubber bushings, though I might consider upgrading the front control arm bushing to an M3 spec part. The car is certainly not a dedicated track car, so keeping a friendly ride is probably more important than finding another .25 sec of laptime.

[1996 328ti]

Originally Posted by Sterndotstern

Thanks for the thoughtful responses, I updated the list above. Based on the feedback here, I'm going to plan to stick with rubber bushings, though I might consider upgrading the front control arm bushing to an M3 spec part. The car is certainly not a dedicated track car, so keeping a friendly ride is probably more important than finding another .25 sec of laptime.

I think solid FCABs are a no brainer.
Then the question is, centered or concentric?

My subframe polyurethane bushings crumbled after 7 years.
I don't know if that's a long time or not, but stock bushings will last longer.

[BimmerBum]

I think you are on the right track with the cooling system so I will not go into detail there.

As for the suspension if you have any intent of doing any track events (and the rules for your class allow) do not go with stock bushings. If you are looking to retain 'stock' feel there are OEM options. Personally, I feel that urethane is perfectly acceptable on a dual purpose car. The most direct impact on ride quality is your shock/strut and spring combo. Bushings (especially the ones you have listed) have more of an indirect impact on ride quality.

For suspension I would start with:

Centered pre-pressed solid lower control arm bushings and a rear bushing kit like the one I carry here. This combo will give you much better feel while maintaining ride quality. It is also the proper foundation to lay before (or in conjunction with) any shock and spring combination.

As for transmission and engine mounts I would go with some OEM options.

OEM Lemforder Motorsport Engine Mounts
OEM Motorsport transmission mounts

While you are there you will also want to take a look at your flex disk or guibo (the bushing between the transmission and the drive shaft).

I have successfully helped other members of this forum down the same path you are on. Feel free to give me a call to discuss. Ed 772.215.4069

[bullmand]

There is a happy medium for some of your bushings. There are several vendors that sell solid rubber transmission and engine mounts. I found that to be a reasonable compromise. You probably won't notice the transmission mounts, but the engine mounts do add some vibration at idle.

[teen ti]

I'm running polyurethane bushings on my double duty ti, auto-x and street car and I honestly don't feel that theres any adverse impact on the ride whatsoever but you can definitely feel a handling difference when pushing the car, granted I'm rather young and a floor with some blankets can suffice as comfortable for me but if it were me I'd definite go with the polyurethane bushings.

[BimmerBum]

You must not be running stock class after all!

Originally Posted by teen ti

I'm running polyurethane bushings on my double duty ti, auto-x and street car and I honestly don't feel that theres any adverse impact on the ride whatsoever but you can definitely feel a handling difference when pushing the car, granted I'm rather young and a floor with some blankets can suffice as comfortable for me but if it were me I'd definite go with the polyurethane bushings.