Track forum general chit chat.

[M3SQRD]

Originally Posted by jmeenach

Yes, same theory applies to OEM bolts. Here is the explanation from the Apex installation sheet:

As with all fasteners, wheel studs and bolts are held in tension, and slightly stretch when installed. After they have been cycled between full torque and then released several times, they eventually lose their elasticity and no longer properly hold tension. While this can’t be seen, it can be measured by precision instruments. Heat also works to embrittle and oxidize metal and brakes generate an incredible amount of heat under hard use. If you are a regular track day participant, it is our recommendation (echoed by many seasoned racers) that you replace your studs annually.

A few of us have been discussing the Schroth harnesses, so regardless of which comment convinced you to pull the trigger, I'm glad it did. Make sure you run a HANS with the harness, as you can cause more harm than good if you aren't using the system correctly. A factory 3-point allows your body to kind of "wrap around" the shoulder portion of the belt, which spreads load across your body. With a 4-point or higher, the inertia is sent to your neck (as your torso will have much less movement), which leads to basilar skull fracture.

Preloading and unpreloading a bolt that’s preloaded to 65-75% of yield (different requirements at different gov’t facilities and aerospace companies) will NOT lose its “elasticity”. To lose “elasticity” you’d have to preload the fastener well beyond its yield strength but even then you don’t really lose “elasticity” when unloaded. The instantaneous stiffness/modulus is the slope of the stress-strain or load-disp curves (no longer a linear relationship between stress and strain). However, it’s still smart to replace studs and lug bolts because threads get damaged with repeated use and the load in the stud/lug bolt increases beyond its preloaded level due to thermally-induced loads/stresses.

Below is a picture showing a fastener being preloaded + an applied load that puts the fastener far past its yield strength and when unloaded it has a slope almost identical to the pre-yield stiffness/slope. However, each time it is re-preloaded, you start to get more displacement/strain until it reaches its ultimate strength and ruptures. The engineering stress-strain (or load-disp) curve shows the stress reducing with increased strain/disp because engineering stress always references the original unstressed cross-sectional area; however, if true stress-strain are used then you see the stress continually increasing until reaching the ultimate strength. This is because true stress is calculated using the instantaneous cross-sectional area which is decreasing with increasing load beyond the yield strength.

The calculations that I’ve performed on the 5-bolt wheel-to-hub bolt pattern shows approximately 10% of the applied lateral bending load is carried by the bolt/stud as an increased axial load (total axial load = applied load*% of applied load carried by studs/bolts + preload + thermally-induced load). It also, conservatively, shows the preload of grade 12.9 (and even 10.9) has sufficient preload from all five bolts/studs is sufficient to prevent the wheel from rotating on the hub (i.e., a lateral load + local bending due to shear are not carried by the studs/bolts). If the joint had gapped than the stud/bolt has to carry almost 100% of the applied axial load + shear load + bending moment due to shear and wheel applied torque..

[Ximian]

Originally Posted by e92BMW///M3

Need to change out fluid and SRF isn't an option.

jritt@essex post is broadly applicable for track use.

I like Motul RBF660 for the price but plenty of people use RBF600 as well. Usually one of the cheapest brake fluids with a high dry boiling point.

[M3SQRD]

Originally Posted by e92BMW///M3

jritt@essex

Saw this post on a different board, wondering if this is chassis dependent or broadly applicable

"Your best bet is to focus on choosing a brake fluid that has a dry boiling point high enough to handle what you're planning to throw at it on the racetrack. With modern brake systems, wet boiling point is no longer as relevant as it once was. Today's systems just don't absorb as much water, as rapidly, as they once did. Also, fluids with a high wet boiling point don't always necessarily offer the best pedal feel due to their chemical composition. I can't tell you how many times we've switched a professional racing driver away from SRF and over to AP Racing and had them instantly tell us how much better their brake pedal feel was.

We (Essex) recommend AP Racing and Ferodo Racing brake fluids. We currently supply brake fluid directly to NASCAR Cup, IMSA, and IndyCar teams, club racers, HPDE drivers, etc. AP Raciing R3 was the gold standard for quite a long time, and now many teams in the elite racing series use AP Racing R4. The AP Racing range in particular has something for every need and budget. For many HPDE drivers, the AP Racing Rad-CAL R2 is the best bang-for-the-buck. It has a high enough dry boiling point to handle what many HPDE guys throw at it, without breaking the bank. We also keep thousands of bottles on the shelf and ready to ship from our Charlotte, NC warehouse at all times, so it's there when you need it most."

Need to change out fluid and SRF isn't an option.

I use AP Racing R3 normal viscosity (NV) brake fluid in my Essex/AP Racing CP9668/CP9449 brake setup and I’m extremely pleased with its performance. I previously used PFC 665 racing brake fluid but the pedal feel is definitely firmer and easier to modulate/release with the R3. I’ve thought about trying the R4 but I haven’t had any issues with the R3. In the winter, I switch to Motul DOT4 low viscosity (LV) brake fluid because our braking systems are designed for LV brake fluid. NV brake fluid works well on track, and summer months, because the brake system temperatures are high enough that the NV fluid is similar to LV fluid. However, street brake temperatures are too low and, therefore, there’s a big difference between LV and NV which can lead to issues with ABS/DSC systems. Switch back to R3 for the track season.

[E92Bean]

Do any of you guys run an oil catch can? I noticed my plenum inlet had a bit of oil in it. As I track my car I’d like to ensure this isn’t an issue.

[Redd]

Originally Posted by E92Bean

Do any of you guys run an oil catch can? I noticed my plenum inlet had a bit of oil in it. As I track my car I’d like to ensure this isn’t an issue.

A light sheen of oil is normal. If the plenum is wet with oil, or there's oil pooling then it's not normal.

[Northbay]

It's been a few years since I've been on track but I recently purchased an e90 m3 and I'd like to get back out. The car is an 08, has had rod bearings/TAs done (as well as a bunch of other stuff - oil filter gasket, oil separators, iacv and lines, valve covers, vanos covers, more). It has 108k miles.

Something to be cautious of or full send? I'm tentatively signed up for a day on May 24.

[CamasM3e93]

Originally Posted by Northbay

It's been a few years since I've been on track but I recently purchased an e90 m3 and I'd like to get back out. The car is an 08, has had rod bearings/TAs done (as well as a bunch of other stuff - oil filter gasket, oil separators, iacv and lines, valve covers, vanos covers, more). It has 108k miles.

Something to be cautious of or full send? I'm tentatively signed up for a day on May 24.

Other than the obvious: tire selection and remaining tread life, brake pads and rotors condition, fresh brake fluid (extra credit for high temperature fluid ), and maybe diff and differential. Those are the things I would look at and potentially address if you’re not sure if done or question if you can complete a day on track unless afdressed.

But other items specific to the e9x m3? Full send, Happily tracking mine at 135k. The only thing that has come up in 8 sessions was the cowbell noise. Mine resolved after replacing the giubo.

[rhyary]

Originally Posted by Northbay

It's been a few years since I've been on track but I recently purchased an e90 m3 and I'd like to get back out. The car is an 08, has had rod bearings/TAs done (as well as a bunch of other stuff - oil filter gasket, oil separators, iacv and lines, valve covers, vanos covers, more). It has 108k miles.

Something to be cautious of or full send? I'm tentatively signed up for a day on May 24.

Full send

[1FastSicilian]

Originally Posted by Northbay

It's been a few years since I've been on track but I recently purchased an e90 m3 and I'd like to get back out. The car is an 08, has had rod bearings/TAs done (as well as a bunch of other stuff - oil filter gasket, oil separators, iacv and lines, valve covers, vanos covers, more). It has 108k miles.

Something to be cautious of or full send? I'm tentatively signed up for a day on May 24.

Originally Posted by rhyary

Full send

What @rhyary said..... just send it!

On a serious note, just make sure you have the proper brake fluid and pads.. Street bads and oem fluid can be a recipe for disaster on track.

[M3SQRD]

Originally Posted by CamasM3e93

Other than the obvious: tire selection and remaining tread life, brake pads and rotors condition, fresh brake fluid (extra credit for high temperature fluid ), and maybe diff and differential. Those are the things I would look at and potentially address if you’re not sure if done or question if you can complete a day on track unless afdressed.

But other items specific to the e9x m3? Full send, Happily tracking mine at 135k. The only thing that has come up in 8 sessions was the cowbell noise. Mine resolved after replacing the giubo.

Did you mean trans and diff?

Definitely agree with starting with fresh fluids/oils everywhere for a car with > 100k miles. Track pads + high-temp brake fluid is needed for track use.

[Northbay]

Originally Posted by 1FastSicilian

What @rhyary said..... just send it!

On a serious note, just make sure you have the proper brake fluid and pads.. Street bads and oem fluid can be a recipe for disaster on track.

Yeah good call - I just put a bottle of ATE Typ 200 in it, but once I’m through that I’m switching to RBF600. I’ll be installing DS2500 front and rear this week, and the car has fresh engine oil, trans and diff fluid are about 1k old.

Glad to hear people have been having success at higher mileage. I know that’s sort of known acceptable on s54 cars, I wasn’t sure about these.

[VicS5]

For those of you thinking about adding lightness…
AC compressor, condenser, and lines (19.66#)
parcel shelf (12#)
SAP (4.68#)
EVAP cannister and hoses (6.7#)
Windshield Washer tank (2.16# + fluid)
Headlight & level sensor delete (15.18#)
Heater core, AC core & dash HVAC (16.66lbs) this excludes the servos and wiring previously removed

[roastbeef]

Originally Posted by VicS5

For those of you thinking about adding lightness…
AC compressor, condenser, and lines (19.66#)
parcel shelf (12#)
SAP (4.68#)
EVAP cannister and hoses (6.7#)
Windshield Washer tank (2.16# + fluid)
Headlight & level sensor delete (15.18#)
Heater core, AC core & dash HVAC (16.66lbs) this excludes the servos and wiring previously removed

sap?

[VicS5]

Secondary Air Pump. Sits in middle right behind plenum.

[roastbeef]

Originally Posted by VicS5

Secondary Air Pump. Sits in middle right behind plenum.

aah, i see. thanks.

[72dan]

Haven't posted in a while.
I took Roast Beef Mike's advice and took my car over to Malek at

MRF Engineering (949) 472-4496

Very impressed with Malek and he does great work. He is one of the few who really knows the E92 and finally a correct 4 wheel alignment with the SPL control arms with weight balance.
My rod bearings weren't as bad as I thought they would be, at 56K miles.
A few SPL arms had to be changed, a previous mechanic had overtightened some bolts resulting in cracks.
I have not tracked the car in years, now on Pilot Sport 4S tires, 275/30/19 front and 295/30/19 rear.
The car drives straight now which is nice. He also bled the brakes, had a tiny bit of air in the rear lines.

[Cmassey3]

Picked up a tow rig project this weekend. A '94 Chevy 3500 with a 454 swap, cammed, .30 over, and with a Holley carburetor. The poor carb tune prevented us from getting past 7 miles with it, so it had to get towed to a shop. Going to be a minute before it's tow ready, but it's got good bones.

[kolosy]

Originally Posted by Cmassey3

Picked up a tow rig project this weekend. A '94 Chevy 3500 with a 454 swap, cammed, .30 over, and with a Holley carburetor. The poor carb tune prevented us from getting past 7 miles with it, so it had to get towed to a shop. Going to be a minute before it's tow ready, but it's got good bones.

man i wish i had the space for a trailer and on-site track car storage. #firstworldproblems

[Cmassey3]

Originally Posted by kolosy

man i wish i had the space for a trailer and on-site track car storage. #firstworldproblems

My goal is to rent the trailer for the time being, it would take 4-6 truck rentals to total the cost it took me to get this one.

[kolosy]

Originally Posted by Cmassey3

My goal is to rent the trailer for the time being, it would take 4-6 truck rentals to total the cost it took me to get this one.

not sure what your home setup is, but i rented a few times (towed with my X5) and it just adds too much time to the process to be worthwhile for most days for me. it was adding an hour to each end, and with a typical 530AM departure time, 8PM return I just didn't want to deal with it.

[Cmassey3]

Originally Posted by kolosy

not sure what your home setup is, but i rented a few times (towed with my X5) and it just adds too much time to the process to be worthwhile for most days for me. it was adding an hour to each end, and with a typical 530AM departure time, 8PM return I just didn't want to deal with it.

I've definitely heard that sentiment before. Ideally I'd get my own flat trailer next season. I kinda have space for it, I could make it work.

[omgzirra_exe]

Just the thought of loading your trailer the night before, then driving to the track, offloading, then reloading, driving again, offloading once more, and parking the trailer just sounds like too much of a hassle for me. Thank goodness I live within a maximum of 2 hours from most tracks in SoCal.

Then I get anxiety from trailer theft these days...