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      04-14-2020, 02:22 PM   #23
Tsauce12
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Wow, this is quite the build. Curious what you did to the interior besides seats. Any gutting? Did you keep the back seats with the cage?
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      04-14-2020, 03:03 PM   #24
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Originally Posted by Tsauce12 View Post
Wow, this is quite the build. Curious what you did to the interior besides seats. Any gutting? Did you keep the back seats with the cage?
I've taken the rear seats out, nothing else. All the other interior bits are still there -- headliner, carpet, door cards, etc.

Answer might be different in a couple of weeks though -- pulling random "unnecessary" bits out of this car is a fun way to pass time during shelter-in-place...

Last edited by msendit; 04-14-2020 at 04:23 PM..
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      04-19-2020, 07:05 PM   #25
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... pulling random "unnecessary" bits out of this car is a fun way to pass time during shelter-in-place...
Yup, I predicted right -- this weekend's pastime was "let's take some bits out of the track car". Gutted some of the rear -- the rear side trim panels, the B and C pillar covers, all 4 OEM seatbelts, and the trunk side liners. Grand total of 40 lbs saved.
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      06-15-2020, 06:17 PM   #26
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Awesome build. Thanks for the read!

Camber arm 'bush' in the upright is a monoball so just the one on the subframe side to change assuming the monoball is all good after that amount of track work.

Did you change the rubber bush in the upright for the forward most link. Think its the traction link? Not sure if parts are available?
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      06-17-2020, 09:29 AM   #27
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Can you provide a link to the delrin bushings you sourced? Love this thread!
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      06-17-2020, 02:10 PM   #28
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I just read this from beginning to end for the first time and enjoyed it very much. I expect that many owners will benefit from your thorough lists and notes in the coming years.

At some point I expect that you'll begin to consider aerodynamics. I had great success with one of this outfit's products: http://www.djracecars.com/carbon-fib...-aerofoils.asp.

After a workup performed on my E36 M3 racecar by Simon McBeath, I ran their SM203 on the car. I'd run a number of wings prior to that. Compared to those wings, the 203 provided a remarkable amount of real, effective downforce.

A bit of a bonus was that the car's top speed was virtually unaffected - a tribute to the wing's efficiency, and something that McBeath had touted during our interchanges before I hired him to do the workup.

DJ Racecars sells only wings and endplates; the wings come with attached brackets for uprights. My shop fabbed the uprights and bolted them to the rear frame rails. Slots were cut in the rear decklid for the upright plates to pass through.

The shop also made an adjustable front splitter out of MDO (https://www.andersonplywood.com/mdo-...nsity-overlay/). This material is heavy, inexpensive, and it's quite easy to cut it and to shape a bullnose leading edge with a router. Once we were set on how long it needed to be, we were going to replace it with a lightweight version. I sold the car before that, though.

One thing that I think is interesting about our cars is that the bottom of the car is flat enough that a real, motorsport-level diffuser may well be an option. When I proposed that the shop create such a diffuser for my E36, the owner said it would be a wasted effort without a flat bottom on the car. This fellow had been Chief Engineer at March Engineering when it was an F1/F2/F3/Indy Car/IMSA constructor, so as badly as I wanted a really cool diffuser on the back of my car, I had to give that idea up.

If we had put a flat bottom on the car (a very do-able project), I would then have been looking at transmission and diff coolers, along with the attendant racket they would have produced. Working up all the common sense I could, I decided to continue working on the driver mod.

In the event they're of interest, I've got photos of:

the mounted SM203 wing,
the wing uprights the shop constructed,
the upright attachments points to the rear frame rails and the trunk,
the deck lid with slots cut into it, and
the splitter, showing its adjustment points and stabilizing turnbuckles.

If you think any of those may be relevant, I'll PM you the links. You may have seen many of them already, as they're scattered about in different threads here on 2addicts.

Re: importing the wing and endplates from England. The transaction took place in the spring of 2012. They were sent by air, and the process was much easier and cheaper than my importation of three heated windshields from England. These were my total expenses for the transaction (note that the now-£1,095 wing was discounted due its being a 2nd (I no longer recall the 2012 list price, but I'm guessing it was £995)):

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      06-17-2020, 02:17 PM   #29
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Quote:
Originally Posted by Coeman140 View Post
Camber arm 'bush' in the upright is a monoball so just the one on the subframe side to change assuming the monoball is all good after that amount of track work.

Did you change the rubber bush in the upright for the forward most link. Think its the traction link? Not sure if parts are available?
Ah, thanks, didn't realize that camber one's a monoball. I'll poke around...

And, no I didn't change the one hubside on the traction link. I don't know of off-the-shelf harder replacement parts for it either. I guess I could do fresh OEM rubber there, possibly with a small metal sleeve insert next time the rear suspension's out. Which is very soon -- these KW shocks finally had enough and took out the rear swaybar and endlinks in the process. Aren't racecars fun?
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      06-17-2020, 02:26 PM   #30
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Quote:
Originally Posted by ifobd View Post
Can you provide a link to the delrin bushings you sourced? Love this thread!
Sure, I have derlin mounts on the subframe and the diff. Both are from Turner.

https://www.turnermotorsport.com/p-1...2-e9x-f22-f3x/

https://www.turnermotorsport.com/p-4...4-f32-f33-f36/
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      06-17-2020, 02:34 PM   #31
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Quote:
Originally Posted by msendit View Post
Quote:
Originally Posted by ifobd View Post
Can you provide a link to the delrin bushings you sourced? Love this thread!
Sure, I have derlin mounts on the subframe and the diff. Both are from Turner.

https://www.turnermotorsport.com/p-1...2-e9x-f22-f3x/

https://www.turnermotorsport.com/p-4...4-f32-f33-f36/
Thanks. Do you think the solid subframe mounts would be too much for a DD?
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      06-17-2020, 02:45 PM   #32
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Quote:
Originally Posted by ifobd View Post
Thanks. Do you think the solid subframe mounts would be too much for a DD?
If I could jump in here, I have Turner's solid aluminum subframe bushings on my car and they've proven to be a non-issue in terms of NVH. I only drove my car 2K before I had all my work done, but the car is fine on the street.

FWIW, I'd rate our roads average in this region - for me, the worst has been in highway construction zones, and there hasn't been much of that that's been an issue.
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      06-17-2020, 03:23 PM   #33
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Quote:
Originally Posted by dradernh View Post
At some point I expect that you'll begin to consider aerodynamics.
Thanks for the aero pointers. I'll keep them in mind, but don't plan to dabble any time soon. More than enough things to setup as is, and aero is notoriously finicky to get right.
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      06-17-2020, 03:28 PM   #34
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Quote:
Originally Posted by dradernh View Post
If I could jump in here, I have Turner's solid aluminum subframe bushings on my car and they've proven to be a non-issue in terms of NVH. I only drove my car 2K before I had all my work done, but the car is fine on the street.

FWIW, I'd rate our roads average in this region - for me, the worst has been in highway construction zones, and there hasn't been much of that that's been an issue.
Agree, there's still plenty of rubber left in other places to soak things up if you only do the subframe mounts.

But comfort things are very subjective, and I'm more in the "stoic" camp, so take that with a grain of salt.
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      06-18-2020, 05:19 PM   #35
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Quote:
Originally Posted by msendit View Post
aero is notoriously finicky to get right.
At our level, I don't think that's the case. There are legions of successful club racers and time trialers who were undaunted by the basic principles involved. Many have gone on to improve their lap times enough to have warranted the time and expense.

A conversation with a shop that's built a number of successful club race cars with aero might be a place to start if you do decide to explore aero at some point in the future.

As always, this is just my 2¢.
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TC Kline Coilovers; H&R Front Bar; Wavetrac; Al Subframe Bushings; 18X9/9½ ARC-8s; 255/35-18 PS4S (4); Dinan Elite V2 & CAI; MPerf Orange BBK; Schroth Quick Fit Pro;
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      07-27-2020, 01:58 PM   #36
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What front lip is that?
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      07-27-2020, 02:13 PM   #37
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Quote:
Originally Posted by aturk View Post
What front lip is that?
It's from RW Carbon, their "3D-style" one.

It's not great, definitely doesn't do anything useful for aero. I mostly put it there so there's something with a flat bottom to mount a splitter to some day (The stock bumper bottom is super irregular). But it's not good even for that -- you can see from the pictures the front of the little lip is pointing up. And "That's not how the force works!".

Oh, also, it has holes for ducting. Which is great! Except... the backside is some weird eliptical shape, so simply clamping a hose there becomes a massive PITA.

Last edited by msendit; 07-27-2020 at 02:36 PM..
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      03-09-2021, 09:06 AM   #38
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Stage 6: COVID

End track hours: ~140
End Laguna Seca time: <didn't go>

End parts/specs:
~3570 lbs max weight (150 driver, full tank); roughly 200 lbs reduction
SPL rear suspension links
Tires: RE71-r 275/35/18 square
Tires: Nankang AR-1 275/35/18 square
12 mm spacer front
MCS 2-way canister shocks
springs: 650 lb in F, 800 lb in R; 6 in tall; 2.25 ID
H&R 20mm rear sway bar
weld-in TCD rollbar
-3.8 F -2.5 R camber; 1/16 F -3/16 R toe

The M240 didn't see that much driving since the last "Stage", for several reasons. First, of course, COVID happened and the tracks were closed for a few months. Then, the first weekend they opened, the rear suspension suspended itself, so another several months in repairs and "while I'm there" upgrades. In the meantime, I finished building my proper racecar, and the bulk of my time and energy went to "race it, break it, fix it". The M240 just sat quietly in a corner, ready to sub in last-minute when the other car had inevitable trouble. Horrible, horrible, first-world problems, I know.



As I wrote earlier, switching to 275/35 tires and replacing the rear end bushings solved two of the biggest issues with the car so far -- failing sidewalls and wandering alignment. Two big ones remained.

First, the KW V3 shocks I had on were slowly starting to go. I first started noticing it near the end of 2019 -- with each track day, the car was getting more and more underdamped. It was especially obvious on tracks like Buttonwillow, where you really have to ride the kerbs to get a decent time -- after a kerb, the car would take 2-3 oscillations to settle. This led to at least one fun 100+ mph "excursion". Ironically, the shocks survived all the kerb hopping of my first post-lockdown track day and let go on the highway a day later. Lots of shock oil sprayed all over RR. Also, with no dampening, the rear swaybar hit the suspension links and snapped, and the pieces managed to puncture the CV joint boots. Talk about an oily greasy mess.

I could've sent the KWs for a rebuild, but at this point they'd served their street/track purpose. Plus, I'd just gotten a tow rig for the MR2, so why not make the M240 less practical and barely streetable as well? So, it got proper motorsports shocks (MCS 2-way), another bump in spring rates (by about 25%), slightly lower ride height, and a 20 mm replacement rear sway bar (up from 19). Oh and a replacement axle because BMW doesn't sell a CV boot kit.

The second big problem, still unsolved, seems to be around overheating. In the past, I've ran it at 100+ ambient temperatures with no trouble at all. But since roughly the end of 2019 again, the ECU occasionally decides to partially cut the throttle on the straights. It took me a while to spot it in the data and convince myself I'm not just driving slowly ("low on power" is the oldest excuse in the book). But the data doesn't lie -- the throttle position occasionally goes down to ~70% while the pedal position is firmly at 100%. Needs more debugging and a cooling system refresh / overhaul.



Anyway, the suspension overhaul had at least some rationale (old one broke). The other updates were a little less... necessary. During the early lockdown months, I was getting pretty bored at home, so I started pulling the interior out to shed some weight. Got rid of the rear side panels, rear bulkhead, a/b/c pillar covers, stock belts, the headliner, and curtain airbags.

Next up was the sunroof. I just wanted to take out the cassette and plug the hole with fiberglass / CF, like people have done on BMWs for decades, for not much money. Turns out, no one makes a delete panel for the F-chassis cars, and the shops that make the various e36/e46/e92 panels all politely told me to pound sand. I asked a local composites shop what it would take to make a one-off piece, they gave me a quote, and I ran away screaming. It was way cheaper to just get a full CF roof, so I just did that. Long story short, the car now weighs ~3570 lbs with a full tank and 150-lb driver, which would be close to 3300 empty. This round of weight reduction cut ~200 lbs from the interior, sunroof, and fender chassis bracing (to make room for taller tires). There's at least another 200 "easy" pounds left in carpet, battery, AC, door cards, etc.

But wait, there's more! With all the interior and sunroof stuff out of the way, the rollbar was now miles away from both the sides and the roof. Which is not an issue per se, but a lost opportunity for extra protection and chassis stiffness. Plus, it doesn't reflect greatly on the fabricator reputation. So, we replaced it with a shiny new one that's nice and snug, plus welded in. This way, when the car inevitably goes wheel-to-wheel racing, it will only need a front half, and a few other small safety bits.



All these Very Necessary upgrades out of the way (and 6 months later), it was time to do some driving. To state the obvious, the car is noticeably faster -- even with the cooling issue cutting some straight line speed and masking some potential pace. I didn't go to Laguna Seca, which I use as a benchmark here, but on the other tracks, it dropped 2-3 seconds per lap.

The MCS shocks soak up bumps and kerbs like magic. It's very confidence inspiring. The rest of the setup changes (springs, bigger rear bar) also feel like a solid step in the right direction -- the car is definitely happier rotating now, without being snappy. If anything, it can probably go a little looser without much trouble.

Front camber right now sits at -3.8, which is too much for the current set of springs / tires. The insides tend to get chewed up under braking pretty fast. Will revert back to -3.5, which is gentler on them.

Speaking of tires, I tried some Nankang AR-1s in addition to the RE71r-s I've grown used to. I've only gone through a single set, so impressions are still initial, but very positive. They're definitely grippier than the 71rs and surprisingly similarly durable (though need to get through a few more sets to judge that). They're at their best at lower pressures -- 32 psi and under for our cars -- and need a bit more warmup.

That's it for now. No more major upgrades planned in the near future, just some small setup tweaks and more hours on the current parts. And sorting out the cooling issue to get back to full power.


Last edited by msendit; 03-09-2021 at 10:17 AM..
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      03-09-2021, 05:44 PM   #39
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Quote:
Originally Posted by msendit View Post
That's it for now. No more major upgrades planned in the near future, just some small setup tweaks and more hours on the current parts. And sorting out the cooling issue to get back to full power.
Pls. ignore if I'm repeating myself...

I have no idea if underhood temps have anything to do with your cooling issue, but on my E36 I was able to lower those temps significantly with a vented hood and Swaintech's White Lightning coating on my headers (https://swaintech.com/race-coatings/...aust-coatings/). The material is a motorsports-quality product.

On a Volvo V70R that I improved, I put White Lightning on the hot side of the turbo housing, too, as well as all the way back to the exhaust tips.

A minor downside of WL is that if the headers need any welding (e.g., an O2 sensor bung gives up and a new one is called for), the thick ceramic coating needs to be ground off in the area needing welding. That's not a big deal for a shop, though.
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TC Kline Coilovers; H&R Front Bar; Wavetrac; Al Subframe Bushings; 18X9/9½ ARC-8s; 255/35-18 PS4S (4); Dinan Elite V2 & CAI; MPerf Orange BBK; Schroth Quick Fit Pro;
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      03-09-2021, 06:01 PM   #40
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Quote:
Originally Posted by dradernh View Post
I have no idea if underhood temps have anything to do with your cooling issue, but on my E36 I was able to lower those temps significantly with a vented hood and Swaintech's White Lightning coating on my headers.
I have no idea either These are both good suggestions to keep in mind...

The thing that gets me is that it used to cool perfectly OK -- so something somewhere regressed. It's probably something simple like blocked radiator fins, or a kinked hose. Just need to spend a day in the shop going through the cooling system(s) piece by piece and see if anything pops up...
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      03-21-2021, 01:20 PM   #41
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Just wanted to jump in here and say thanks for a good Sunday read.
I love that you went from no track experience to an all out baller.
I went and did the one day M School in SC a few weeks ago, and the race bug has bitten me.
Look forward to more updates!
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      03-23-2021, 10:01 PM   #42
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Quote:
Originally Posted by msendit View Post
Stage 6: COVID

End track hours: ~140
End Laguna Seca time: <didn't go>

End parts/specs:
~3570 lbs max weight (150 driver, full tank); roughly 200 lbs reduction
SPL rear suspension links
Tires: RE71-r 275/35/18 square
Tires: Nankang AR-1 275/35/18 square
12 mm spacer front
MCS 2-way canister shocks
springs: 650 lb in F, 800 lb in R; 6 in tall; 2.25 ID
H&R 20mm rear sway bar
weld-in TCD rollbar
-3.8 F -2.5 R camber; 1/16 F -3/16 R toe

The M240 didn't see that much driving since the last "Stage", for several reasons. First, of course, COVID happened and the tracks were closed for a few months. Then, the first weekend they opened, the rear suspension suspended itself, so another several months in repairs and "while I'm there" upgrades. In the meantime, I finished building my proper racecar, and the bulk of my time and energy went to "race it, break it, fix it". The M240 just sat quietly in a corner, ready to sub in last-minute when the other car had inevitable trouble. Horrible, horrible, first-world problems, I know.



As I wrote earlier, switching to 275/35 tires and replacing the rear end bushings solved two of the biggest issues with the car so far -- failing sidewalls and wandering alignment. Two big ones remained.

First, the KW V3 shocks I had on were slowly starting to go. I first started noticing it near the end of 2019 -- with each track day, the car was getting more and more underdamped. It was especially obvious on tracks like Buttonwillow, where you really have to ride the kerbs to get a decent time -- after a kerb, the car would take 2-3 oscillations to settle. This led to at least one fun 100+ mph "excursion". Ironically, the shocks survived all the kerb hopping of my first post-lockdown track day and let go on the highway a day later. Lots of shock oil sprayed all over RR. Also, with no dampening, the rear swaybar hit the suspension links and snapped, and the pieces managed to puncture the CV joint boots. Talk about an oily greasy mess.

I could've sent the KWs for a rebuild, but at this point they'd served their street/track purpose. Plus, I'd just gotten a tow rig for the MR2, so why not make the M240 less practical and barely streetable as well? So, it got proper motorsports shocks (MCS 2-way), another bump in spring rates (by about 25%), slightly lower ride height, and a 20 mm replacement rear sway bar (up from 19). Oh and a replacement axle because BMW doesn't sell a CV boot kit.

The second big problem, still unsolved, seems to be around overheating. In the past, I've ran it at 100+ ambient temperatures with no trouble at all. But since roughly the end of 2019 again, the ECU occasionally decides to partially cut the throttle on the straights. It took me a while to spot it in the data and convince myself I'm not just driving slowly ("low on power" is the oldest excuse in the book). But the data doesn't lie -- the throttle position occasionally goes down to ~70% while the pedal position is firmly at 100%. Needs more debugging and a cooling system refresh / overhaul.



Anyway, the suspension overhaul had at least some rationale (old one broke). The other updates were a little less... necessary. During the early lockdown months, I was getting pretty bored at home, so I started pulling the interior out to shed some weight. Got rid of the rear side panels, rear bulkhead, a/b/c pillar covers, stock belts, the headliner, and curtain airbags.

Next up was the sunroof. I just wanted to take out the cassette and plug the hole with fiberglass / CF, like people have done on BMWs for decades, for not much money. Turns out, no one makes a delete panel for the F-chassis cars, and the shops that make the various e36/e46/e92 panels all politely told me to pound sand. I asked a local composites shop what it would take to make a one-off piece, they gave me a quote, and I ran away screaming. It was way cheaper to just get a full CF roof, so I just did that. Long story short, the car now weighs ~3570 lbs with a full tank and 150-lb driver, which would be close to 3300 empty. This round of weight reduction cut ~200 lbs from the interior, sunroof, and fender chassis bracing (to make room for taller tires). There's at least another 200 "easy" pounds left in carpet, battery, AC, door cards, etc.

But wait, there's more! With all the interior and sunroof stuff out of the way, the rollbar was now miles away from both the sides and the roof. Which is not an issue per se, but a lost opportunity for extra protection and chassis stiffness. Plus, it doesn't reflect greatly on the fabricator reputation. So, we replaced it with a shiny new one that's nice and snug, plus welded in. This way, when the car inevitably goes wheel-to-wheel racing, it will only need a front half, and a few other small safety bits.



All these Very Necessary upgrades out of the way (and 6 months later), it was time to do some driving. To state the obvious, the car is noticeably faster -- even with the cooling issue cutting some straight line speed and masking some potential pace. I didn't go to Laguna Seca, which I use as a benchmark here, but on the other tracks, it dropped 2-3 seconds per lap.

The MCS shocks soak up bumps and kerbs like magic. It's very confidence inspiring. The rest of the setup changes (springs, bigger rear bar) also feel like a solid step in the right direction -- the car is definitely happier rotating now, without being snappy. If anything, it can probably go a little looser without much trouble.

Front camber right now sits at -3.8, which is too much for the current set of springs / tires. The insides tend to get chewed up under braking pretty fast. Will revert back to -3.5, which is gentler on them.

Speaking of tires, I tried some Nankang AR-1s in addition to the RE71r-s I've grown used to. I've only gone through a single set, so impressions are still initial, but very positive. They're definitely grippier than the 71rs and surprisingly similarly durable (though need to get through a few more sets to judge that). They're at their best at lower pressures -- 32 psi and under for our cars -- and need a bit more warmup.

That's it for now. No more major upgrades planned in the near future, just some small setup tweaks and more hours on the current parts. And sorting out the cooling issue to get back to full power.

So great to see an update on this. I also applaud your commitment on the carbon roof. I recently picked up an f80 m3 and it's one of my favorite parts. Maybe someday for the m235!
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msendit415.50
      09-05-2021, 10:40 AM   #43
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A quick aside on tires

Over the last few months, I went through a few different types of track tires on the M240. Figured, I'd share my notes here.

No, I didn't test them back to back on the same day, but we'll use Sonoma in the morning (ambient temps 60-70 F) as a bit of benchmark. Car setup stayed the same with all these, which I think makes for an interesting comparison. Even if the tires are in pretty different categories from each other. All tires are 275/35/18. Typical disclaimer, tires are very setup dependent -- don't trust a random guy on the Internet, do your own testing.

Bridgestone RE-71r (33-34 psi hot, 1:55.X at Sonoma)
That's the benchmark I'd been used to over the years. Pretty good for a street tire. Takes no time to warmup, but also gets greasy pretty fast. Ok in the wet. Discontinued now, it seems.

Nankang AR-1 (30-31 psi hot, 1:53.X at Sonoma)
Nice big step up in grip from the 71r. Surprisingly lasts about the same as them. Setup-wise, didn't seem to like as much camber as the other tires here. Sliding it is manageable, but a little chompy, not quite smooth. 275/35/18 seems impossible to find in the US now.

Pirelli PZero DHH (28-30 psi hot, 1:52.X at Sonoma)
I'm really not doing these slicks justice, since I got a takeoff set from a racing team (with presumably 1-2 race heatcycles on them) and put another 4 HC before taking them to Sonoma. Wasn't as life-changing compared to the Nankangs, as I'd expected. I'm sure stickers would blow the socks off any other tire I tested (everyone I've talked to says their first HC is crack). Very good and progressive (though quiet) when sliding. They lost longitudinal grip way before lateral -- as long as I was careful with the throttle / brakes, I could eek ~10 HC on top of whatever they'd done before.

Toyo RR (29-30 psi hot, 1:51.X at Sonoma)
Pretty popular race tire with NASA. I've run them on many other cars, but felt a bit different on the heavy M240. They definitely like their slip angle (nice and smooth), and get pretty loud when you get them near the limit. Could use more camber, especially compared to the Nankangs. Grip peak was high, but relatively narrow compared to the others here -- had to constantly dance on the wheel throwing the car between US to OS to keep them there. Lasted about 15 HC (though slowed down a bit after ~10).

Hankook Z214 (C51 compound) (~29 psi hot, 1:50.X at Sonoma)
Fun tire. First heatcycle felt bananas (but times don't reflect that, someone put it in the wall early on during that outing). Wider grip peak than the Toyos, also quieter. Fronts started going after only 6 HC, which is not great. Needed pretty extensive warmup. I haven't driven Hoosier R7s, but it seems like they're pretty similar.

Last edited by msendit; 09-06-2021 at 01:44 PM..
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dradernh4179.00
      09-22-2021, 10:02 AM   #44
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Terrific thread.

Did you have an optimal ride height? As measured from centre of wheel hub to fender.

Also, 1mm in size sway bar - noticeable?

Thanks
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