Ordered an M3P, any thoughts on planned upgrades

[thegraybeast]

I have an M3P arriving shortly and I am trying to get together all my mods before it arrives.

Doing 35% all the way around and PPF on front end day 1.

Where I have questions is suspension/wheels/tires. i have been reading on this for days and everyone seems to have different assessments of what can/should be done here

Ideally, I would keep the 20x9s and put 275/30/zr20 P4S tires on with ohlins and sway bars.

Many people act like 245/255 are the absolute largest that can be done on the front. people also say that you need 9.5-10.5 inch rim for a 275. I can totally understand if I were wanting perfection, I’d do a 9.5, but that adds ~5k to the car (not worth in IMO).

The P4S specs a 9-10 inch rim in this size (275/30/20). I have a car with factory P4s at 9.5, so not apples to apples to apples but still not 10+

Also, there is a YouTube video of someone with a stock white 3 with 275/30/20 on his stock 20x9s with no rubbing. I do not understand why people act as if you have to grind on suspension parts to fit 275s or have extreme offsets. Has something changed on the m3 suspension? Are people all taking about the old 8.5s?

I also see rim sets sold staggered… like 275/245 (10/9) And people on YT doing this. Why would you want to run a staggered setup on this car? It seems like AWD would prefer a square setup

From what I see, the 275s would fit, and add no mass (comparing Tesla tire weight to p4s)… is there some great compelling reason to not do 275? Alternately, if I would choose to waste the 5k on rims, I could cut ~9lbs per corner and have a more “ideal” platform for 275s… is that worth the money? Of course, if I find the 9s handle like complete trash, I could always do wheels later… I’m not sure why so few have tried this

Oh, and if my reasoning is needed for the suspension, I am looking for better handling (not softer ride), and a car that doesn’t look like it’s on stilts. Even 275s will look small in the rear, imo. I don’t care whatsoever about range. I do possibly care about warranty issues, but not with the parts I replace because that’s just obvious.

 

[The Other Dan]

For coilovers, MPP comfort or sports, or Ohlins R&T depending on just how much you want to spend.

For rims, if you want to stay with 20s for the looks, I cant help you. Most people who autox or race will put on 19s or even 18s for weight and tire selection. At that point you can go 275 pretty easy, 295 if you have supporting mods, and 305s if you get aggressive. There's a "wide tire and wheel" thread floating around during with lots of info. You're not traction limited, so unless you do autox or race, there's not much point going very wide. Just get a more aggressive offset on your wheels and go 245/255.

 

[stevehifi]

There’s no need to put a super wide tire on a 9” rim, you’re not going to get any benefit in contact patch at all. In fact all you’re doing is adding unnecessary unsprung weight and cost buying a bigger tire. Ideal for the 9” is a 245 since it translates to a 9” contact patch which is perfect.
If you really want to go wide because you track your car then buy yourself a set of 18 or 19s in 9.5” wide and run a 265 200tw tire.
Recommend though that you still run stock wheels and tires on street because wide tires will kill your efficiency and ride quality.
Suspension wise MPP is the go to choice. If you drive on the street get comfort coilovers. If you track or autox go with sport.

 

[pdx_m3s]

There’s no need to put a super wide tire on a 9” rim, you’re not going to get any benefit in contact patch at all. In fact all you’re doing is adding unnecessary unsprung weight and cost buying a bigger tire. Ideal for the 9” is a 245 since it translates to a 9” contact patch which is perfect.
If you really want to go wide because you track your car then buy yourself a set of 18 or 19s in 9.5” wide and run a 265 200tw tire.
Recommend though that you still run stock wheels and tires on street because wide tires will kill your efficiency and ride quality.
Suspension wise MPP is the go to choice. If you drive on the street get comfort coilovers. If you track or autox go with sport.

It’s a game of trade offs with tire size. With such a heavy car, a larger tire (even on a 9” rim) can help with the tires getting too hot when pushing them hard.

My rule of thumb is to match tread width (per TireRack) with wheel width. This is generally a 255 tire for a 9” wheel. 245 works too and will help not hurt efficiency too much.

 

[stevehifi]

It’s a game of trade offs with tire size. With such a heavy car, a larger tire (even on a 9” rim) can help with the tires getting too hot when pushing them hard.

My rule of thumb is to match tread width (per TireRack) with wheel width. This is generally a 255 tire for a 9” wheel. 245 works too and will help not hurt efficiency too much.

-The Pzero for our cars is XL RF rated for high load, so I wouldn't worry about heat issues the side walls are built tough to handle the weight and punishment
-Even with the stock camber (about -1 deg) I've pushed the car very hard and the edges of the tires have held up perfectly

255 is pretty much the max you can put on a 9" but then again you're adding a heavier tire, and now you're throwing off the the speedo since you're
at effective diameter of 27" vs 26.5" (OEM).

 

[pdx_m3s]

-The Pzero for our cars is XL RF rated for high load, so I wouldn't worry about heat issues the side walls are built tough to handle the weight and punishment
-Even with the stock camber (about -1 deg) I've pushed the car very hard and the edges of the tires have held up perfectly

255 is pretty much the max you can put on a 9" but then again you're adding a heavier tire, and now you're throwing off the the speedo since you're
at effective diameter of 27" vs 26.5" (OEM).

My reference to heat was how it interplays with grip, not in terms of tire integrity. Too little or too much results in sub-par grip. Model 3 has a tendency to heat up tires a lot on track because of its weight.

 

[stevehifi]

My reference to heat was how it interplays with grip, not in terms of tire integrity. Too little or too much results in sub-par grip. Model 3 has a tendency to heat up tires a lot on track because of its weight.

very possible.. honestly if you're going to track the car definitely get another set of wheels and some track specific tires (ideally in a 265-275 width on a 9.5-10.5 rim).
Doesn't make any sense to run a street tire at the track unless its raining.

 

[gearchruncher]

275's on 9" wheels is pointless. Good chance you'll make the car slower.

https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=296

I know 275's are possible on stock offsets because I run them. But on much wider wheels, and with camber.

 

[Lavender]

I'd add this to the pot. The stock Uberturbines are heavy, and even if you squeeze a 275 on them, they still aren't great for performance, and the sidewalls will bulge which isn't ideal for traction and handling.

Regarding staggered setups- Manufacturers do this (generally on rear drive, or rear biased AWD) to help tame oversteer. IMHO it also looks better, but is obviously subjective. I have 255/35/20 on the front, and 295/30/20 on the rear. looks beefy and handles great, all while reducing the weight of the OEM setup.

as for handling- Unless you intend on tracking the car, you may want to install a good set of Sway bars first before spending the cash on coil overs. ALOT of the unwanted dive and roll can be mitigated this way and you may be happy with the way it handles. (I installed the Unplugged performance bars on full stiff, and it made a dramatic difference without sacrificing comfort, and still preventing ripping off the bumper on speed bumps or angled driveways etc.).
I agree that the wheel gap is a bit ridiculous aesthetically, but the roads are just too shitty in CO to lower it any further

 

[gearchruncher]

ALOT of the unwanted dive

Can you explain how sways impact dive? Sways only do something when the left and right wheels on the same axle try to move a different amount. Dive is a front/rear axle motion, which sways cannot control.

It's interesting that you have picked out needing more grip in the rear. Many people that track their cars have found that only a rear sway is needed- and a rear sway by definition is used to move grip from the back to front.

 

[Lavender]

Sway bars effect the combination of dive and roll in a turn. The greater the steering angle, (especially when braking) the car will want to roll and dive, but by preventing the roll with stiffer sway bars, the car will also dive less because the suspension has to do less work controlling the roll. Im my opinion, the OEM sway bars on these cars are no where near "Performance" indicated in the name of the trim level. The addition of the front aftermarket sway bar greatly improves turn in and steering response as well as front end roll

I didn't choose the staggered setup for more grip in the rear, I did it because I like they way it looks. If I was going to track this car, I'd put the lightest, widest 18" wheels I could fit in a square setup, and some MPP or Unplugged coil overs.

 

[MountainPass]

Also, the sway bars do effect dive on their own because the bar acts like a spring when both wheels on the same axle compress at the same time. The middle of the bar is fixed to the chassis, while the ends of the bar attach to the strut. When both wheels travel upwards in the wheel well, the bar being fixed to the chassis tries to pull them back down.

Aftermarket sway bars are not bonded to the bushings like the OEM sway bars. It can swivel freely in the mounts!

 

[Lavender]

Aftermarket sway bars are not bonded to the bushings like the OEM sway bars. It can swivel freely in the mounts!

Truth, I stand corrected. Only the OEM bars can do this.

 

[stevehifi]

the stock swaybars are absolutely fine on the stock or modified car. they don't affect dive or squat in any way...

roll is not a bad thing, it lets the car compress and extend side to side and helps maintain mechanical grip. Adding more bar just makes the ride rougher since you are transferring more road noise to the car with a stiffer axle.

always start upgrades with shocks/springs first and use the low speed adjustments on the shocks help level the car in transitions. Bars are just meant as a tuning tool to help induce/reduce under/over steer when at different tracks.

 

[gearchruncher]

the stock swaybars are absolutely fine on the stock or modified car. they don't affect dive or squat in any way...

roll is not a bad thing, it lets the car compress and extend side to side and helps maintain mechanical grip. Adding more bar just makes the ride rougher since you are transferring more road noise to the car with a stiffer axle.

always start upgrades with shocks/springs first and use the low speed adjustments on the shocks help level the car in transitions. Bars are just meant as a tuning tool to help induce/reduce under/over steer when at different tracks.

This is so overly-simplistic that it's kind of worthless. Suspension tuning is a very detailed field that likely nobody here is an actual expert at (except maybe a few of our best vendors). But saying the stock bars are fine, shocks should always be first, roll is not a bad thing, etc can be totally wrong for some cars. Without detailed analysis of the whole suspension geometry, exact shock rates, tires, etc, nothing is absolute. Yes, too stiff is bad. Too soft is too.

Just to use examples of how silly it is to be this absolute, why do stock cars come with sway bars or springs at all? If more roll is good and bars are only a tuning tool for specific tracks, stock cars would come with the softest suspension possible and no bars at all since they cost money and weight. Shocks and sways do very different things and are used for much more precise adjustments than over/understeer- as they have dramatically different time constants and thus impact dynamic situations vs static ones quite differently.

 

[stevehifi]

This is so overly-simplistic that it's kind of worthless. Suspension tuning is a very detailed field that likely nobody here is an actual expert at (except maybe a few of our best vendors). But saying the stock bars are fine, shocks should always be first, roll is not a bad thing, etc can be totally wrong for some cars. Without detailed analysis of the whole suspension geometry, exact shock rates, tires, etc, nothing is absolute. Yes, too stiff is bad. Too soft is too.

Just to use examples of how silly it is to be this absolute, why do stock cars come with sway bars or springs at all? If more roll is good and bars are only a tuning tool for specific tracks, stock cars would come with the softest suspension possible and no bars at all since they cost money and weight. Shocks and sways do very different things and are used for much more precise adjustments than over/understeer- as they have dramatically different time constants and thus impact dynamic situations vs static ones quite differently.

I'm not making a generalization, i'm referring to the model 3's setup. I have MPP's full setup and running their bars too, although they are very good I have them on the softest settings when i run at the track. I'll maybe put the rear swaybar on a stiffer setting for the tight courses or autox but that's it. IMHO I could probably get away with the stock ones, definitely don't need a stiffer bar in the front ... that loads the outside tire way too much (push). The rear is really
where I feel it makes of a difference (go look at UPP's site, they have way more variations of the rear).

MPP has said themselves that they didn't see the value in bigger bars and they offer them more for tuning for different courses. If you want to reference a vendor then there you have it.

 

[turns2stone]

I have an M3P arriving shortly and I am trying to get together all my mods before it arrives.

Doing 35% all the way around and PPF on front end day 1.

Where I have questions is suspension/wheels/tires. i have been reading on this for days and everyone seems to have different assessments of what can/should be done here

Ideally, I would keep the 20x9s and put 275/30/zr20 P4S tires on with ohlins and sway bars.

Many people act like 245/255 are the absolute largest that can be done on the front. people also say that you need 9.5-10.5 inch rim for a 275. I can totally understand if I were wanting perfection, I’d do a 9.5, but that adds ~5k to the car (not worth in IMO).

The P4S specs a 9-10 inch rim in this size (275/30/20). I have a car with factory P4s at 9.5, so not apples to apples to apples but still not 10+

Also, there is a YouTube video of someone with a stock white 3 with 275/30/20 on his stock 20x9s with no rubbing. I do not understand why people act as if you have to grind on suspension parts to fit 275s or have extreme offsets. Has something changed on the m3 suspension? Are people all taking about the old 8.5s?

I also see rim sets sold staggered… like 275/245 (10/9) And people on YT doing this. Why would you want to run a staggered setup on this car? It seems like AWD would prefer a square setup

From what I see, the 275s would fit, and add no mass (comparing Tesla tire weight to p4s)… is there some great compelling reason to not do 275? Alternately, if I would choose to waste the 5k on rims, I could cut ~9lbs per corner and have a more “ideal” platform for 275s… is that worth the money? Of course, if I find the 9s handle like complete trash, I could always do wheels later… I’m not sure why so few have tried this

Oh, and if my reasoning is needed for the suspension, I am looking for better handling (not softer ride), and a car that doesn’t look like it’s on stilts. Even 275s will look small in the rear, imo. I don’t care whatsoever about range. I do possibly care about warranty issues, but not with the parts I replace because that’s just obvious.

I am now on my second Model 3 Performance.

IMO, the first 'performance' upgrade you can make is smaller/lighter wheels. I recently went from the stock 20" Uberturbines to the 19" Sport V2 wheels. Much more comfortable ride, at least 5% better mileage. Handling feels good!

 

[pdx_m3s]

I am now on my second Model 3 Performance.

IMO, the first 'performance' upgrade you can make is smaller/lighter wheels. I recently went from the stock 20" Uberturbines to the 19" Sport V2 wheels. Much more comfortable ride, at least 5% better mileage. Handling feels good!

Stealth mode

 

[Clover]

This is so overly-simplistic that it's kind of worthless. Suspension tuning is a very detailed field that likely nobody here is an actual expert at (except maybe a few of our best vendors). But saying the stock bars are fine, shocks should always be first, roll is not a bad thing, etc can be totally wrong for some cars. Without detailed analysis of the whole suspension geometry, exact shock rates, tires, etc, nothing is absolute. Yes, too stiff is bad. Too soft is too.

That was not worthless and is general suspension tuning theory. Of course it varies based off what else you do to your car, but there are a lot of people out there who might not be benefiting from their aftermarket bars at all depending on their driving. The idea you want to eliminate sway from you car is commonly perpetuated myth or overblown at the very best. Books on the subject will generally tell you what the above poster just did. You are correct that shock tuning and anti-sway bars tuning and effects are different and many cars have them for reasons. Normally adjusting your anti sway bars is a final tuning tweak in racing car setup books and conventional wisdom.

I'm not sure on this, but I suspect anti-sway bars prevalence has come from the autoX crowd. A stiffer setup can be helpful mainly in slalom type situation where you are turning from one direction to another and then back again. A stiffer bar minimizes the weight shift allowing you to go from a turn one direction to a turn another direction easier. Going really stiff can make it easier to rotate the car on a tight turn as well. However, for a road car this is often not a good tradeoff. A stiffer bar is often going to hurt your mechanical grip around a sweeping turn and the car is going to be more unsettled over bumps with stiffer bars. Similar to why cars moved from live rear axels to indecent rear suspensions, you want each wheel independent in general. You are right you want some weight on the inside wheel in a turn, but you don't actually want 50/50.

If you're building a track car that is not going to see bumps, cool go for stiffer bars to a point if you want. AutoXing, cool. Go for it. However, for a street car, saveing the money or spending it elsewhere is not worthless advice.

Back to the original poster. Ohlins are pretty great but also pretty expensive. I put them on a BMW in the past and am not sure I'd go for them again for a few reasons. The first is that you adjust compression and rebound together. There are not separate adjustments for each, like there should be in my opinion. For the screen on my old BMW, I wanted the compression as soft as I could get it but more rebound control. Not possible with Ohlins. Both compression and rebound are adjusted together. Their cost is also pretty high and you really should have them rebuilt, I'm thinking it was at 30K miles or less. At that time, you had to send them off to have them rebuilt. I think it was Europe but maybe they have somewhere in the States now. I did the install myself and then the uninstall back to stock for the rebuild needed to take it for an alignment after each. If you're not DIYing the install, you're probably looking at close to $2K/year for your shocks over three years with Ohlins. They are good, but expensive and I don't think most people think of rebuilding them like they should. Their spines did not used to be that great in the past. I don't know if that is still true, but I changed to a set of Swift springs.

I also always seem to go down the path of trying to stuff as much rubber under a car as I can. In the car I'm building for myself, I had a set of custom wheels made so I could fit a 285/325 tire setup. Probably half the time I end up shooting myself in the foot doing this. I can think of at least three times that that I rubbed bad on setups others claimed fit. You always find out when you got all your friends in the car or when you're at the track which is always awesome. I keep telling myself not to push things anymore with tire fit, and yet... I can't seem to help myself.

 

[gearchruncher]

A stiffer bar minimizes the weight shift allowing you to go from a turn one direction to a turn another direction easier.

I suggest you read this series on suspension basics, which is excellent: Explained: Weight transfer vs body roll (part 1)

Which includes this exact quote:

But of course, a problem arises. The stiffer the bar, the more weight is transferred across that axle, and the less grip that pair of tires makes.

That series also covers the fact that all suspension tuning is a compromise:

However, body roll brings about various problems of its own which we need to understand and try to solve for. The trouble we run into is that every solution for body roll creates some other problem(s), and we are left needing to decide where to make compromises.

Again, my only point here is that anyone that says "body roll is good" or "always start with shocks" or "roll bars are only for autox" without it being against a very specific vehicle is just misleading people that would go and apply that to all cars.

But we're also dealing with an OP who has never returned to this thread, and is clearly more concerned with looks than actual performance, so this is all academic.