-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
P3D+ Street/Track/Time Trial Build
- Thread starter MasterC17
- Start date
jyalpert
Member
Yeah, my Miata is not particularly comfortable with fiberglass buckets. My wife mostly refuses to ride in the car, and my seats are bolted to the floor with no slide, so she can barely drive it. I put quick disconnects on the airbag and other sensors, but it still takes over an 90 minutes to do a seat swap back to stock, so I almost never do it.
The Hybrid is super cool. I planned to start coaching at HPDE and was going to get one, but then my wife got pregnant and it was decided from on high that I shouldn't be riding in newbie drivers' cars...
Anyway, sick build. I'm very jealous of the MCS coilovers. Would be curious to see your alignment specs as well. The stock alignment range on the 3 seems a bit wide and eventually I'd like to get some custom values dialed in, even though I never plan to track mine.
Interesting- is the purpose to give you HANS protection without a harness?
I was thinking of putting a race seat and harness in but did a bunch of research and found lots of conflicting info, but consensus (as much as it exists) among folks who would seem to know was that seat/harness/HANS without a cage is a bad idea (getting smashed like an upright bug if the roof collapses in a rollover) and there’s no way I’m putting a cage in a street/track car, personally. If I get serious enough about track driving i’ll probably buy a dedicated track car. Shame because I enjoy driving the 3 on the track quite a bit.
jyalpert
Member
Yeah, the Hybrid is like a HANS lite. You can see Randy Pobst wearing it in marketing materials for TeslaCorsa, and you can see Matt Farah wear one whenever he's driving someone else's car on track. Lots of HPDE instructors have them. It's definitely not as good as a HANS from what I understand, but it's a lot better than nothing. They're pricey, though.
Lots of debate around when a harness/fixed back seat is appropriate. As they say, safety is a system, and once you've departed from the car's stock safety system, you're into sort of a "level of comfort is up to you" situation. It is quite easy (and common) to make a car LESS safe by installing fixed back seats.
3pt seat belts are intended to work together with reclining seats in the event of a rollover - I believe the seat is designed to break at the hinge, and your body can fold over the diagonal portion of your seat belt, thereby providing you some room to move if the roof collapses. My understanding is that the safety strategy is to allow your body some degree of controlled movement, and then catch your movement with airbags and such.
With a fixed back seat, the strategy is entirely different. The goal is to keep your body in one place, and protect you with a rigid outer structure. Your body is of course held in one position, so if you end up on your head, the only place for the force to go is onto your spine. Because your body can't move, it's important to brace your head and neck with a HANS, and maybe with a containment seat.
I'm not sure if I'd be comfortable putting one in a car without a roll bar (which is what I have in my Miata - much different than a full cage as the car is still driveable on the street - you'll see a roll bar in the Porsche GT3 for instance) and without a harness bar. I do see lots of people run this setup at HPDE, though. And honestly, before I got my fiberglass seats and HANS, I would come home from track days with a sore back and neck from bracing myself in position during cornering. So I get why it's also attractive from a practical perspective.
The odds of a rollover are low at the track, and the odds of a subsequent roof collapse are even lower still, especially if your seat is mounted to the floor and you have a lot of space between your helmet and roof. Modern cars like the 3 have had to build to even more stringent rollover standards as well.
To me, the best you can do is go into it with eyes open that your safety is entirely up to you and your personal level of comfort.
Last edited:
Good conversation regarding safety. I think it really comes down the Model 3 being already quite safe with the stock system and robust in a rollover, which is very unlikely anyway. Sticking with the stock system and adding a Hybrid HANS-type device is the best bet unless you are building an all-out race car with a cage (which I don't see happening any time soon).
I wanted to show off my alignment specs. Something else I haven't yet shared is my prototype front upper control arms with offset bushings. As you can see, I was able to gain an additional 1.5 degrees of negative front camber after lowering it, bringing me to a total of 3 degrees of negative front camber. I also included some better photos of the rear control arms and you can see the Ground Control weight jacker kit (which literally means adjusting the rear suspension up and down takes a 17mm socket on a wrench).
I wanted to show off my alignment specs. Something else I haven't yet shared is my prototype front upper control arms with offset bushings. As you can see, I was able to gain an additional 1.5 degrees of negative front camber after lowering it, bringing me to a total of 3 degrees of negative front camber. I also included some better photos of the rear control arms and you can see the Ground Control weight jacker kit (which literally means adjusting the rear suspension up and down takes a 17mm socket on a wrench).
Attachments
jyalpert
Member
Ooh nice. A couple questions:
- what is the effect of front toe out? Does the car tramline on the road? I like sensitive steering with near zero toe, but toe out is usually too much for me on other cars. Yet I see the M3 has a stock toe range including toe out! Wondering about steering dynamics.
- does the car tend to push? +2 degree negative front camber vs rear should counter it if so... and since its high power AWD, wondering if a little push is OK? Maybe you'd trail brake and then get on the throttle really early after apex to bring the front around?
(Side note - the pushiest car I ever drove was a Yugo in a Lemons race on Walmart tires. It would start to slide at 25mph in a corner. The only way to drive it fast was to give it more throttle when it started to push. It would still understeer, but it would also bring the front around. Totally counter to normal weight transfer strategy. We were also totally destroying tires!)
- how sensitive is handling to ride height differential front to rear? My Miata is extremely sensitive to ride height changes, to the degree that 1/4" change in front ride height can make the car tail happy vs neutral. But the M3 is way heavier, so not sure if it would be as dramatic?
- how neutral is the car as stock?
- what is the effect of front toe out? Does the car tramline on the road? I like sensitive steering with near zero toe, but toe out is usually too much for me on other cars. Yet I see the M3 has a stock toe range including toe out! Wondering about steering dynamics.
- does the car tend to push? +2 degree negative front camber vs rear should counter it if so... and since its high power AWD, wondering if a little push is OK? Maybe you'd trail brake and then get on the throttle really early after apex to bring the front around?
(Side note - the pushiest car I ever drove was a Yugo in a Lemons race on Walmart tires. It would start to slide at 25mph in a corner. The only way to drive it fast was to give it more throttle when it started to push. It would still understeer, but it would also bring the front around. Totally counter to normal weight transfer strategy. We were also totally destroying tires!)
- how sensitive is handling to ride height differential front to rear? My Miata is extremely sensitive to ride height changes, to the degree that 1/4" change in front ride height can make the car tail happy vs neutral. But the M3 is way heavier, so not sure if it would be as dramatic?
- how neutral is the car as stock?
It took me a while to gather all the data/upload video/etc from Hyperfest last weekend but here it is.
Big Takeaway:
Hyperfest is CRAZY. It was absolutely packed. My run group had 50-75 cars on track each session. Finding open room was near-impossible. I uploaded the cleanest lap I could find which still has me passing 4 cars and pointing 1 (Radical) by. Nonetheless, that lap was only 1 second slower than my previous best lap (clean).
Track Analysis:
Overall it went fairly well! The good news is I dropped time off all eight sectors, and even though a few sectors I couldn't get clean runs through I still managed to cut a total of 2.5 seconds when compared to March, bringing the total theoretical lap time down to a 2:09.804. This is using a 10Hz GPS, so the timing should be accurate even at a sector-level.
Scoping through the data, my cornering speeds were anywhere from 3-15% higher than in March on the stock suspension and stock aero. I was also able to put the power down much quicker. Even though power was a bit limited compared to March (ambient temps then were 50-60f, this time it was 75-90f), I was still able to achieve minimally faster straight speeds (140mph back straight, 136 front straight). I don't think I ever pulled onto the straights without being behind someone, and such was the case with most of the track, which made consistent data very difficult to procure.
I will say I think there is a lot of time to be gained with an open track and refining my line. I wouldn't be surprised if the car is capable of hitting a 2:05 with the current configuration.
Video:
Street Analysis:
The new aero and suspension has resulted in a roughly 17% increase in efficiency based on my own data. I took a trip today and recorded the following:
Miles Driven: 50
Average Speed: 74.88mph
Wh/Mi: 255
Ambient Temp: 95f
HVAC: A/C On, 75f
Before, I was averaging around 300Wh/Mi with the HVAC OFF at 75MPH.
So, certainly a noticeable and rather staggering improvement!
In regards to downforce/cornering, my carrying speed on the esses at VIR improved by 4.2%, so there's some hard data to back up improvements there as well.
Overall, I think the MCS Coilovers and Unplugged Performance Front Lip played a big part in the improvements on the car, both for the street and for the track. The additions of my own rear custom diffuser and control arms also helped. I would also like to note the Raybestos ST47's held up MUCH better than the Hawk DTC-70's. Even though they have fairly similar feel, stopping power, and fade resistance, the Raybestos still have 75-80% life left after 3 days, whereas the Hawk's were more than 50% worn after 2 days. Not to mention, the Raybestos are cheaper. Definitely sticking with the ST47's going forward.
Any questions ask away!
Big Takeaway:
Hyperfest is CRAZY. It was absolutely packed. My run group had 50-75 cars on track each session. Finding open room was near-impossible. I uploaded the cleanest lap I could find which still has me passing 4 cars and pointing 1 (Radical) by. Nonetheless, that lap was only 1 second slower than my previous best lap (clean).
Track Analysis:
Overall it went fairly well! The good news is I dropped time off all eight sectors, and even though a few sectors I couldn't get clean runs through I still managed to cut a total of 2.5 seconds when compared to March, bringing the total theoretical lap time down to a 2:09.804. This is using a 10Hz GPS, so the timing should be accurate even at a sector-level.
Scoping through the data, my cornering speeds were anywhere from 3-15% higher than in March on the stock suspension and stock aero. I was also able to put the power down much quicker. Even though power was a bit limited compared to March (ambient temps then were 50-60f, this time it was 75-90f), I was still able to achieve minimally faster straight speeds (140mph back straight, 136 front straight). I don't think I ever pulled onto the straights without being behind someone, and such was the case with most of the track, which made consistent data very difficult to procure.
I will say I think there is a lot of time to be gained with an open track and refining my line. I wouldn't be surprised if the car is capable of hitting a 2:05 with the current configuration.
Video:
Street Analysis:
The new aero and suspension has resulted in a roughly 17% increase in efficiency based on my own data. I took a trip today and recorded the following:
Miles Driven: 50
Average Speed: 74.88mph
Wh/Mi: 255
Ambient Temp: 95f
HVAC: A/C On, 75f
Before, I was averaging around 300Wh/Mi with the HVAC OFF at 75MPH.
So, certainly a noticeable and rather staggering improvement!
In regards to downforce/cornering, my carrying speed on the esses at VIR improved by 4.2%, so there's some hard data to back up improvements there as well.
Overall, I think the MCS Coilovers and Unplugged Performance Front Lip played a big part in the improvements on the car, both for the street and for the track. The additions of my own rear custom diffuser and control arms also helped. I would also like to note the Raybestos ST47's held up MUCH better than the Hawk DTC-70's. Even though they have fairly similar feel, stopping power, and fade resistance, the Raybestos still have 75-80% life left after 3 days, whereas the Hawk's were more than 50% worn after 2 days. Not to mention, the Raybestos are cheaper. Definitely sticking with the ST47's going forward.
Any questions ask away!
Attachments
I'll do my best to answer these questions.
I was planning to do an alignment with 0 toe in the front, but it was late and I was running out of time so I just matched factory for ease. I have since done another alignment, and set it to 0, and it feels great!
I really don't find the car pushing much. It definitely pushed a little on stock suspension, but at this point the car is predictable and neutral. For a 4,100lb car, you don't feel the weight nearly as much as you might expect. I think a lot of that has to do with the weight being down low and the low center of gravity. I am planning on dropping down to 265 tires (from 275) as I don't feel the additional weight and rolling resistance of the 275's is worth it.
I haven't found the ride height to make a big difference. It felt really good stock, and now it feels better. It isn't a drastic improvement, but a noticeable improvement. I dropped the car about 1.5" all around. That said, the traction/stability/motor control when using Track Mode is phenomenal. It actually seems to add to the driving experience and it will let you get pretty out of control before intervening. The car kind of just pulls you around the track (in a good way). I found it to be faster down the straights than most cars (the exceptions being Camaro ZL1's and similar 600hp+ cars), and it can keep in the twisties with the best of them (Miata's/E36's/etc).
Overall, for a car that I can (comfortably) drive home, it's incredible. Oh yeah, I am also saving $200+ in gas each track day!
That's expected for Hawk pads, they suck, only acceptable on light cars that don't need much brakes.
Raybestos/Porterfield pads are great for heavy cars, originally designed for nascar back in the day. Caveat is that even their st-43 is way too aggressive for a light car like a miata.
My current plan is to grab the girodisc rotors from mountainpass, and then send a brand new set of pads to raybestos/porterfield for them to measure and make the custom size, very affordable. They are a traditional race shop like coleman racing, so horrible website, but if you give them a ring they take care of you. Wendy at porterfield really knows her stuff, schooled me a few times on friction compound splits between axle's and why my great idea is actually terrible, lol.
How are you charging up at the track? RV 50amp?
How long are the sessions, how much % do you drain, how much % do you can back charging between sessions?
Raybestos/Porterfield pads are great for heavy cars, originally designed for nascar back in the day. Caveat is that even their st-43 is way too aggressive for a light car like a miata.
My current plan is to grab the girodisc rotors from mountainpass, and then send a brand new set of pads to raybestos/porterfield for them to measure and make the custom size, very affordable. They are a traditional race shop like coleman racing, so horrible website, but if you give them a ring they take care of you. Wendy at porterfield really knows her stuff, schooled me a few times on friction compound splits between axle's and why my great idea is actually terrible, lol.
How are you charging up at the track? RV 50amp?
How long are the sessions, how much % do you drain, how much % do you can back charging between sessions?
Charging with 50amp outlet, 200V @ 40Amps (Gen 1 UMC). I start @ 95%, drain about 40%, charge about 20% between sessions. Can squeeze out 4 sessions a day (20 mins each).
It's been a while, but I wanted to update this thread. My next event is November 1st-3rd @ VIR.
I have a lot to do to the car before that event.
I am hoping this event is not as hot, and that it is less crowded than HyperFest was. I also had far too much pre-load on the front sway bar last event, which was not helping in corners. Tesla also finally enabled CHAdeMO Charging, which VIR just happens to have right on-track, which means I can begin each session at 90%SOC.
I have a lot to do to the car before that event.
- Unplugged Sway Bars w/ Whiteline Adjustable Links (Front + Rear)
- Updated Rear Camber Arms (Prototyping w/ new Bushings)
- Updated Front Control Arms (Prototyping w/ new Bushings)
- Updated Aero Shield Brake Ducting (Moved to Outer Edges for Aerodynamic Purposes)
- RacingBrake XT970 Rear Pads
- New Tires (Either Another Set of Nexen's, or 265 Ventus R-S4's)
- Schroth Quick-Fit E90 Harness (Thanks to Another Forum Member for Info)
I am hoping this event is not as hot, and that it is less crowded than HyperFest was. I also had far too much pre-load on the front sway bar last event, which was not helping in corners. Tesla also finally enabled CHAdeMO Charging, which VIR just happens to have right on-track, which means I can begin each session at 90%SOC.
It's automatically interpreted by the G force data captured from the phone. It's not actual brake pedal application.
What wheels and tires (size?) were you using during this trip? What rear rotors are you currently using?
What was your ride height set at?
Can we get a review of the MCS coilovers on the street?
Will you be getting a higher downforce rear spoiler?
What material comprises the body of the MCS coilovers? Is the coilover lighter than stock?
Does the rear of your car still get dirty after the diffuser installation?
Thank you
What wheels and tires (size?) were you using during this trip? What rear rotors are you currently using?
18" Wheels from Tire Rack (22lbs each) on stock 18" Michelin MXM4's. Stock Performance Rear Rotors.
What was your ride height set at?
~14" All-Around
Can we get a review of the MCS coilovers on the street?
They ride quite nice, but they are not quiet. As everything is basically solid you get some noise from the top hat and the helper spring at low speeds with high steering angle.
Will you be getting a higher downforce rear spoiler?
Yes, on order from UP, should be coming in October.
What material comprises the body of the MCS coilovers? Is the coilover lighter than stock?
I'm not 100% sure but I think they are aluminum. They are ridiculously light, I would guess between 1 and 2 lbs for the damper.
Does the rear of your car still get dirty after the diffuser installation?
Honestly, I have not payed enough attention to notice!
Thank you
Similar threads
