My E90 M3 Dedicated Track build (with pix!)

[dogbone]

Originally Posted by dapopa9

Are you faster on the R1S than the Hoosier A7's?

I'm surprised more the SLB unlimited guys don't run Michelin/Pirelli or other race slicks. I haven't ran these myself but in talking with some of the bigger budget race teams they tell me they are 2-3 seconds fast than the A7's.

I have had both brand new A7 and R1S on the car. They can net very similar lap times. I am going to give the edge to the R1S. They are very different tires though. Let me know if you want me to elaborate. Everyone knows I'm good for a long answer!!

Slicks are faster than A7 and R1S. No question. I'd agree with the comment that slicks are 2-3 seconds faster, but they have to be new, and you better be able to adapt quickly to them, which can be challenging because the cherry grip happens on the first laps of the slicks. You can't toss a slick on the car, and then take 4 heat cycles to figure them out. The sweet high grip is gone by then.

At SLB 2017, I saw a number of the cars in Unlimited Class with slicks. Who was contending that didn't have slicks? In Unlimited RWD, I saw for myself that me in 4th, the M4 in 3rd and the RX7 in 2nd had slicks. (My slicks were not new.) I never saw what the winning Miata had on it.

[dapopa9]

Emilio in the 1st place URWD Miata wasn't running slicks. He had Hoosier A7's on it. Then I noticed you said you were running R1S but didn't realize you also ran some slicks.

Get some new ones next year instead of the used ones!!

[dogbone]

Originally Posted by dapopa9

Emilio in the 1st place URWD Miata wasn't running slicks. He had Hoosier A7's on it. Then I noticed you said you were running R1S but didn't realize you also ran some slicks.

Get some new ones next year instead of the used ones!!

My car is not running 1:44's....regardless of the tires. It's far too heavy. Those Miatas are around 1000 lbs lighter than my car......

In Unlimited RWD, 2nd, 3rd, 4th and 6th for sure all ran slicks at some point. (I don't know anything about the S2000 in 5th place.)

Here's what all this boils down to for me: I've had funky luck at Super Lap Battle the past 2 years. I just cannot find open laps/clear track when it counts. Someone just sent me a link to the Miata's 1:44 lap. The Miata had two very courteous drivers who let him by without impeding his way on that lap. He was VERY lucky. That lap could EASILY have been blown by a rude driver. I did not have such luck. So, I'm not blowing $2000 tires at a GTA event hoping people won't hold me up for several turns (which they did), or that other cars don't breakdown in my session (which they did), or that some guy doesn't crawl on his warm up lap and screw the entire session of cars behind him (which happened), or that the session is red flagged on my final turn of the track during the fastest lap I ran at the event because of a car on fire (which happened), or that the track is clean (can you say dusty?)....oh, and I had an air intake problem which didn't help. That's a lot of distractions. And I still managed 4th, which given my history of lap times at BW is the absolute best I could have placed in this particular event. (I've never driven a 1:47, let alone a 1:47.2 like the M4 did for 3rd). So, I placed as high as I could have regardless of the conditions.

(In the past, when I've bought $2000 slicks, I booked a semi-exclusive day and went on my own.)

Anyway, at the end of the day, my car isn't a time attack car. It's just a track car that I go hit the time attack circuit with. And it does well at local events. I've won local GTA, Redline, Speed SF and PCA-SanDiego time trial events. But SLB attracts crazier cars. SLB crams more cars on track than any other event. And they ran 6 run groups on Day 1 which forced them to run 15 minute sessions. That's ok. I try to learn something from each event. Next year, hopefully I'll show up with more knowledge and with even more driving skills, so I DON'T RUN OUT OF TALENT!!!

[///Mobbin]

Originally Posted by ///Mobbin

I'm running MCS 2WNR's. It sounds like one issue with going into higher tender/assist territory is that you start getting into the complexities of a dual spring type of setup and that can be time consuming to test, tune, and get right. That said, I do like experimenting and I already have the helper perches so I thought I'd try something out, though more on the helper/tender side of things. I went ahead and ordered some real-rate helpers/tenders in 168 lbs/in, Swift Helper Springs. I will likely pull these back out when I go for 10.5" front wheels later this year but wanted to give them a try and see if I can feel the difference. At COTA I like to drive over the curbing, so hoping to test these out there.

I wanted to report that though these helper/tenders worked well for me I'm now planning to pull them and run just 6" front springs with no helpers. I'd rather maximize my tire space (as you've mentioned) and I think my car felt slightly more dialed in on track w/o them, hard to know for sure though as I've been changing multiple things at once.

[dogbone]

Originally Posted by ///Mobbin

I wanted to report that though these helper/tenders worked well for me I'm now planning to pull them and run just 6" front springs with no helpers. I'd rather maximize my tire space (as you've mentioned) and I think my car felt slightly more dialed in on track w/o them, hard to know for sure though as I've been changing multiple things at once.

Yeah with MCS and JRZ, the higher up the spring perch is, the wider wheels and tires you can run. I use 5" front springs.

Once you start down the rabbit hole of wider front wheels, you will love the extra front grip. However, going fat means those tires are going to be rubbing all over the place. So, be prepared for rub marks everywhere in those wheel wells.

With my VF supercharger intake tube running down there in the front-driver wheel well, I've been fighting fat front tries rubbing the intake tube and disconnecting the air hose. It's causing havoc and ending my track days early....my next project at Racewerkz is finding a permanent solution for this nagging issue. I suspect the solution will not be too easy.....

[dogbone]

I just picked up my M3 from Racewerkz today. They installed the new Track Spec hood vents. I'm loving the look! Beyond the cosmetics, I hope they encourage more air to flow through the main radiator, I hope they allow a bit more heat to escape from the engine bay and I hope I get a tiny bit of "anti-lift" effect (I'm not gonna call it downforce) from potentially lowering pressure in the engine bay/under the hood. I'm not looking for any miracles, but one can hope that the sum of all the shit happening on the front of my car adds up to something useful!

They also installed a new air intake tube for the supercharger. We're hoping this one is gonna sit there happily and quietly with fat tires up there. They shaped the tube and worked hard to keep it pretty darn far away from the tire. Buttonwillow's Off Ramp turn is the spot that shines the harshest light on this issue---lots of steering input on a super tight turn, slow speeds, high G's (1.8+G), uphill, (shitty surface with multiple pavement-types)....that turn is one big ball of fun...... My next track days look to be elsewhere, so it's gonna be awhile before I can test it there.....

Anyway, I'm quite excited to drive the car with these new tweaks!

PS. The guys at the shop were laughing because the front of the car is so damn busy and they back of the car has absolutely nothing going on.......hmmmm....the back of the car.......I wonder if......

[rcracin]

LOL there definitely is a lot going on up front.

Is the car originally designed for air to enter through the front and escape through the bottom? What happens when air escapes through the top? Does it affect aerodynamics or downforce in any way?

[roastbeef]

i bet they can make a fender vent that would really look great.

[dogbone]

Originally Posted by rcracin

LOL there definitely is a lot going on up front.

Is the car originally designed for air to enter through the front and escape through the bottom? What happens when air escapes through the top? Does it affect aerodynamics or downforce in any way?

The lip/splitter combo was not scientifically designed as far as under-car airflow. The parts were acquired separately. It works great though!!

The prevailing consensus is that in a stock S65 engine bay, there’s a fair amount of pressure that builds up when going fast; perhaps even pushing up on the hood creating lift. The hope is that by allowing the air to escape, we can alleviate the pressure, and even encourage more airflow through the radiator. Can that be called “downforce” or “anti-lift”? Who knows. The Track Spec vent hoods were still prototype in November. Chopping up an E9x M3 is still a fairly novel thing in the general consumer hobbyist aftermarket. I don’t think anyone has all the specific answers for this platform yet. It’s been an expensive platform to experiment on until recently.

[AriuSen]

Wow the vents made the car look so much more agreessive now.

[dogbone]

Originally Posted by AriuSen

Wow the vents made the car look so much more agreessive now.

Yeah, I like the look of the vents quite a lot.

I hope there's a performance benefit too. I need something to help me chase that Z4 of yours!!!!

[spxxx]

Originally Posted by dogbone

Yeah, I like the look of the vents quite a lot.

I hope there's a performance benefit too. I need something to help me chase that Z4 of yours!!!!

+1 .... Also, lets hope for more proper N54 builds out there pushing the envelope. The cars are basically free now which has drastically skewed the driver demographic (negatively in a lot of aspects) but hopefully we see more people willing to gut them and do the racecar thing.

Stoked to start competing with some of y'all M folks - breaking 2min at BW CW13 makes you think you can actually drive a car.

[dogbone]

I had an opportunity to drive Inde Motorsport Ranch in Arizona recently. It's a very nice facility. The owner of Inde was spending some time at the track while we visited and took us on a tour of his private garage. He has all kinds of toys---not just cars and motorcycles. The entry driveway to the ranch is lined with old fighter jets hehe.....the owner called the entire facility a "sand box"---a place for grownups to play. And it really is.

I mean, c'mon look at the jets!!!



The track itself is very tough--very technical. I am a better driver after leaving Inde. Aside from the long back straight, it's a tight course, and I found myself in 2nd gear (DCT) more than any other track. It twists and turns CONSTANTLY. It's off-camber in a lot of places. It has blind corners in many spots. It's got many small hills to deal with. There are a lot of turns to remember. It took a whole day to get the back part of the course in my head. On most of the course, if you're trying to "go for it", the tail of the car is in a constant state of wanting to step out on you. Aero is not that effective on most of the course because you just can't get fast enough. However, Turn 3 definitely DOES benefit from aero and I was glad to have it there. It's definitely very challenging.

During our two days, we drove a bunch, hung out a bunch, worked on our cars, ate good food, and our host was extremely gracious. What more can you ask for?

This was my first time driving with the hood vents. Since I had never been to this track it was hard to judge if there was any difference in feel. My new air intake held up pretty well. (We'll have to see how it does at Buttonwillow now.)

2009 E90 M3
Track/course: Inde Motorsport Ranch - Full Course
Best Lap Time: 1:51.04 (AIM Solo DL)
Brakes: AP Racing - Cobalt Friction XR2 front/XR3 rear
Tires: Pirelli Slicks
Suspension: JRZ RS Pro
Other mods: VF620, RD Sport front sway bar, car is gutted with full roll cage, APR 67" GT-250 wing, carbon lip, APR front splitter, AJ Hartmann Canards, Track Spec hood vents, Akrapovic X-Pipe, exhaust: straight through with resonators, do88 DCT cooler, Recaro Pro Racer halo seat, DSC-off

Here's the video: (the rearview mirror is more prominent than usual because I moved my camera mount due to re-installing my passenger seat. I'll have to work on that......or ditch the OEM mirror for a proper race car mirror that sits higher. There's always something to work on.... )

[rcracin]

that's so awesome.

[FrostyAZ]

That is an awesome time. Most people struggle to break 2 minutes. The Inde race group ran this configuration in October and the fastest times were 1:55's so to get down to 1:51 is really good. I don't know much time the SC helps to pick up but I know it's not the SC alone. You have to be a skilled driver to get that type of lap time. I think this means you should join Inde 🤑. They do have a time trials series as well.

[dogbone]

Originally Posted by FrostyAZ

That is an awesome time. Most people struggle to break 2 minutes. The Inde race group ran this configuration in October and the fastest times were 1:55's so to get down to 1:51 is really good. I don't know much time the SC helps to pick up but I know it's not the SC alone. You have to be a skilled driver to get that type of lap time. I think this means you should join Inde 🤑. They do have a time trials series as well.

Thanks!

Over the years, people have told me that they believe a supercharger gives you 1-2 seconds at a track like Buttonwillow that is 2.7 miles long. My AIM data says that the Inde Course I drove is 2.28 miles. With Inde having more corners to launch out of in low gears, I'm going to assume that the 1-2 seconds thought holds up.

hehe Inde is 600 miles from my house....That's a bit out of range for me to visit regularly. A time trial series there would be interesting though.

[AriuSen]

Here's the video: (the rearview mirror is more prominent than usual because I moved my camera mount due to re-installing my passenger seat. I'll have to work on that......or ditch the OEM mirror for a proper race car mirror that sits higher. There's always something to work on.... )

[/QUOTE]
Wouldn't be better to get a 71" wing for your car? Mine is 67" too. Nice driving BTW!

[dogbone]

Originally Posted by AriuSen

Wouldn't be better to get a 71" wing for your car? Mine is 67" too. Nice driving BTW!

Thanks!

Regarding aero----(Disclaimer: I've only been experimenting with aero on my car for the last couple years, so as I like to always say, I'm not an expert on this topic.) In my experience, I have learned that a very important part of aero is the balance between the front aero and the rear aero. What I have found in these last couple years is that, with a 67" wing, I am not wishing for rear downforce. What I wish, EVERY TIME I GET IN THE CAR, is that I had more front downforce. So, while 71" might get me a bit more rear downforce, I would be concerned that I cannot balance it out with more front downforce.

Have you seen the front of my car? I have done every single thing I can to get that front to hold as much as I can---lip, splitter, canards, hood vents, cutouts in wheel arches.....the only thing I have held back on is a longer splitter, which I know would be more effective, but I don't trust myself to rip the damn thing off with an off-track excursion. So, practicality is holding me back with the splitter length.

There's a few other things to consider that might be viable alternatives to a massive wing that creates more drag:

-We could consider a more powerful wing than a GT-250. The GTC-300 provides even more downforce given the same size as a GT-250. But again, can you balance it out?

-I guess active aero could be considered, although I've never looked into it. It might solve the balancing problems at high speeds in rounders.

-We could consider a rear diffuser. Interesting possibilities there, but seems to require quite a bit of custom work.

-We could consider a flat bottom. LOTS of custom work.....


I find the topic of aero very interesting. I love what it did to my car, and my approach is very simple. It's clear that a sophisticated aero setup could really boost a car's performance, but it seems that on this platform, the sophisticated setups are not readily available for purchase. I'm really curious to drive my new hood vents at Buttonwillow!!

[///Mobbin]

Have you considered the jakob66 diffuser? LINK

Active aero is also a really interesting option, could go flat on the straights! Just pricey, LINK.

[dogbone]

Originally Posted by ///Mobbin

Have you considered the jakob66 diffuser? LINK

Active aero is also a really interesting option, could go flat on the straights! Just pricey, LINK.

I have a sedan. Unfortunately, readily available things like the diffuser just don't fit my car.

The idea of active aero is cool. The price of active aero means it's not going on on my car!

[ThunderMoose]

My understanding is that flat bottom and proper rear diffuser is a big difference maker in grip but like you say it's a ton of customization.

Do you ever run with NASA? You should. Nationals this year are at COTA. I believe your car would be very competitive in their TT program.

[dogbone]

Originally Posted by ThunderMoose

My understanding is that flat bottom and proper rear diffuser is a big difference maker in grip but like you say it's a ton of customization.

Do you ever run with NASA? You should. Nationals this year are at COTA. I believe your car would be very competitive in their TT program.

NASA is basically the only major organizer that I have not run with yet.

Can you tell me the format of how they run the TT series? Do they have special TT sessions and spread everyone out by a few seconds and pre-grid by lap time? Or is it a find-an-open-lap-the-best-you-can-in-a-regular session?

I have become more curious about NASA events as I hear you guys talk about Eastern State this-and-that, Western State this-and that, National something-or-other. It sounds fun.

COTA is DEFINITELY on my list of tracks to attend, but living 1400 miles from there has kept me away. And of course, showing up to COTA for the first time at a big event like that might not be the best strategy either, but it does sound fun!