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      11-05-2017, 06:15 AM   #23
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Quote:
Originally Posted by Bee Pee View Post
How do you code m2 to show true speed ?

It reads like 275/35/19 is a size that actually makes M2 speedo read more accurately - is this really the case ?
Yes, a larger diameter will make the speedometer read a "slower" speed, and since the standard setup is programmed to always read (real speed - 5kph), i.e. 3.1mph, it will slightly close that gap. In this case though, the delta will be speed dependent as opposed to the static 3.1mph offset since the diameter is now 1.1% larger.

It's a standard coding parameter -- at least in the E9x series, you can code the central display to show speed (stock is not to show digital speed); then you can choose to have it show factory offset value or true speed. It shows the coding parameter to have the actual speedometer analog gauge to show true speed, but apparently that is disabled on North American delivered cars for some reason. At least it is using Carly -- more than likely actually coding with NCSExpert or other tool would allow that too.

In any event, I used a Carly Gen 2 along with the Pro version of their app to change it along with other things I wanted to code on my cars.
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      11-05-2017, 12:34 PM   #24
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Originally Posted by omasou View Post
I didn't do the math assumed Keith gave me the correct sizes?
Those are 1 increment is size larger than stock not smaller. It will slightly increase actual speed for the same indicated value. If you haven't coded your car to indicate true speed, it will be showing (speed - 3.1 mph) anyway, so if anything it will indicate a tad closer to true speed.

On my E90 M3 I run the same sizes (stock sizes are same as M2: 245/35-19, 265/35-19), and even with the car coded for true speed, my GPS verified speed is spot on accurate.
Ah forgot about speedo. The difference is usually negligible like you showed. I had thought he was talking about front to back and confusing the DSC.
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      12-27-2017, 02:39 PM   #25
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So is there any type of consensus on the front sway bars yet?

I really liked the adjust ability of the front bar on my E92 M3, but I just got off the phone with Dinan and they don't seem to want to split up the set at all. So far as I can tell, that leaves AFE and H&R as the bar options. AFE seems cheaper but there's limited info available as to the actual stiffness of the bar compared to stock. Same goes for the H&R.
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      12-27-2017, 06:24 PM   #26
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I wanted the adjustability so got the Dinan set and left the rear bar in the box. It’s the best front bar so an extra few hundred bucks at this point, who cares.

Also, for those asking earlier about the 305/30R19 bridgestones and whether they fit, I already mentioned in a previous post in this thread that they fit. There was a m2 at 2017 SCCA Nationals running them in the rear.
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      12-27-2017, 06:44 PM   #27
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Originally Posted by Sprockett View Post
I wanted the adjustability so got the Dinan set and left the rear bar in the box. It’s the best front bar so an extra few hundred bucks at this point, who cares.

Also, for those asking earlier about the 305/30R19 bridgestones and whether they fit, I already mentioned in a previous post in this thread that they fit. There was a m2 at 2017 SCCA Nationals running them in the rear.
On what wheel setup were they running a 305?
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      12-27-2017, 11:30 PM   #28
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Originally Posted by Sprockett View Post
I wanted the adjustability so got the Dinan set and left the rear bar in the box. It’s the best front bar so an extra few hundred bucks at this point, who cares.
It’s somewhere around $500 extra, at which point I start to care. And again, there’s no definitive answer as to why it’s “the best”, so why buy 2 bars when I only need one?
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      12-28-2017, 12:40 AM   #29
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Originally Posted by BAN_M2 View Post
On what wheel setup were they running a 305?
Stock wheels.
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      12-28-2017, 12:45 AM   #30
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Originally Posted by Wisco M3 View Post
It’s somewhere around $500 extra, at which point I start to care. And again, there’s no definitive answer as to why it’s “the best”, so why buy 2 bars when I only need one?
It’s the bar with the largest range as you know and since the car is basically a complete unknown at this point, it’s the safest bet that one of the settings is going to work for you. If you are just hoping for someone to tell you which bar is ‘best’ I guess that’s different but...who are you gonna trust?
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      12-28-2017, 06:21 AM   #31
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Quote:
Originally Posted by Wisco M3 View Post
It’s somewhere around $500 extra, at which point I start to care. And again, there’s no definitive answer as to why it’s “the best”, so why buy 2 bars when I only need one?
It appears that the AFE is non-adjustable and 32mm. It is tubular also but with unknown wall thickness. One could assume it is similar to the OEM wall thickness; however, doesn't the OEM bar have a reduction in cross-section in the middle? That fubars the analysis a lot. You could at least calculate the increase in stiffness vs OEM by assuming the OEM bar is not necked down and ratio the diameters to the 4th power -- then you would know the actual increase is somewhat larger than that value since the AFE bar is a continuous cross-section. All of this of course assumes the moment arm is the same length, but that is easy to measure between the two. AFE sould be able to answer these questions.

The H&R bar is 30mm and solid? Not sure. At least it has two adjustment holes. It is priced at $417 though...

The other potential cheap option is to use the M3/4 comp package sway bar. I assume it's larger but just don't know the sizes to compare. The parts catalog no longer calls out sway bar diameters. It can be had for $202 though, new.

All that said, it does appear the Dinan bar would be what's needed to tune the car, especially if trying 275/35-18 square versus 275/35-18F & 305/30-19 rear, etc.

Sounds like a fun time to be had nonetheless!

Regards,
Chuck
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      12-28-2017, 09:16 AM   #32
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[edit] Both ECS and Turner have the Dinan set on sale right now for 10% off. I think that's probably the way to go since you get a bigger bar with lots of adjustability potential and adjustable end-links to go with it. I'm glad I looked.

As an aside, I'm probably going to settle on 275/35-18 square for the first season with the car. I'll see how that goes and adjust for the '19 season based on actual experience.
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      12-28-2017, 10:06 AM   #33
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Quote:
Originally Posted by CLH View Post
[edit] Both ECS and Turner have the Dinan set on sale right now for 10% off. I think that's probably the way to go since you get a bigger bar with lots of adjustability potential and adjustable end-links to go with it. I'm glad I looked.

As an aside, I'm probably going to settle on 275/35-18 square for the first season with the car. I'll see how that goes and adjust for the '19 season based on actual experience.
Dinan direct offers the set at 15% off through the 31st.

I think I'll be running the same setup and seeing how it fares. I'm supposed to be running in Spec Solo Coupe, but then I bought this and I'm not sure if I want to mess around co-driving the torqueless wonder.
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      12-28-2017, 05:02 PM   #34
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Quote:
Originally Posted by Wisco M3 View Post
Dinan direct offers the set at 15% off through the 31st.
Top tip, thank you!

ECS has them 10% off with free shipping, but Dinan direct is ~$20 less as long as you aren't a CA resident who needs to pay them sales tax.
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      12-28-2017, 08:02 PM   #35
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I’ll save the best for last. Tischer BMW is offering Dinan at 20% off and free shipping. Getbmwparts.com. Promo code is dinanyes. It’s good until the 31st.
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      12-29-2017, 06:21 AM   #36
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Quote:
Originally Posted by Wisco M3 View Post
I’ll save the best for last. Tischer BMW is offering Dinan at 20% off and free shipping. Getbmwparts.com. Promo code is dinanyes. It’s good until the 31st.
Might as well pickup a Dinan exhaust for less than $1500 too while you're at it! This is a great deal by Tischer on all Dinan stuff.
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      12-29-2017, 07:00 AM   #37
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Quote:
Originally Posted by CSBM5 View Post
Quote:
Originally Posted by Wisco M3 View Post
IÂ’ll save the best for last. Tischer BMW is offering Dinan at 20% off and free shipping. Getbmwparts.com. Promo code is dinanyes. ItÂ’s good until the 31st.
Might as well pickup a Dinan exhaust for less than $1500 too while you're at it! This is a great deal by Tischer on all Dinan stuff.
I know the general approach for ax is to get as much tire under the car as possible, but my race shop is telling me customers with M2s running big tire widths on stock wheels are getting funky wear patterns, meaning the contact patch is sub-optimal.

To guys running 265, 275 or 285s on stock suspension (and thus with little ft camber): Are you seeing evidence (from the wear pattern) that the tires are rolling over or mis-shaping and not putting the power down correctly across all the extra tire you are paying for?

I know it's all different when you move to camber plates and coilovers. I'm just talking about a BS setup. What does your wear pattern look like with big meats?
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      12-29-2017, 08:37 AM   #38
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By referring to "putting power down" I may have implied rear tires, but want to hear about both ends. Dynamically, the front certainly has a lot going on. I'm just curious if this is one of those cars where more tire isn't necessarily better at some point.
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      12-29-2017, 10:30 AM   #39
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Originally Posted by CSBM5 View Post
Might as well pickup a Dinan exhaust for less than $1500 too while you're at it! This is a great deal by Tischer on all Dinan stuff.
That is 100% the plan.
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      12-29-2017, 12:33 PM   #40
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Quote:
Originally Posted by jnoyes View Post
I know the general approach for ax is to get as much tire under the car as possible, but my race shop is telling me customers with M2s running big tire widths on stock wheels are getting funky wear patterns, meaning the contact patch is sub-optimal.

To guys running 265, 275 or 285s on stock suspension (and thus with little ft camber): Are you seeing evidence (from the wear pattern) that the tires are rolling over or mis-shaping and not putting the power down correctly across all the extra tire you are paying for?

I know it's all different when you move to camber plates and coilovers. I'm just talking about a BS setup. What does your wear pattern look like with big meats?
I’m running 265/285/35 4S on the OEM wheels. Wear is even with -2.7 front and -2.0 rear camber. This is on a track, tho, not AutoX.

Last edited by ZM2; 12-30-2017 at 06:56 PM..
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      12-29-2017, 01:04 PM   #41
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Quote:
Originally Posted by jnoyes View Post
I know the general approach for ax is to get as much tire under the car as possible, but my race shop is telling me customers with M2s running big tire widths on stock wheels are getting funky wear patterns, meaning the contact patch is sub-optimal.

To guys running 265, 275 or 285s on stock suspension (and thus with little ft camber): Are you seeing evidence (from the wear pattern) that the tires are rolling over or mis-shaping and not putting the power down correctly across all the extra tire you are paying for?

I know it's all different when you move to camber plates and coilovers. I'm just talking about a BS setup. What does your wear pattern look like with big meats?
I’m running 265/285/35 P4S on the OEM wheels. Wear is even with -2.7 front and -2.0 rear camber. This is on a track, tho, not AutoX.
Right, and with camber plates too, I presume given the amount of front camber you are getting.
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      12-29-2017, 01:17 PM   #42
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Right, and with camber plates too, I presume given the amount of front camber you are getting.
Yeah, Dinan suspension and Vorshlag plates.

The sidewall isn’t as stiff on the 4S vs RE-71R or R888R, and it does roll over a little. Grip and feel is still good tho.

If you ran a 265 4S on a 9” OEM wheel exclusively for AutoX, I do think you would wear the shoulder off before the rest of the tire, even with -2.7 camber. But, I’m doubting this will be a pure AutoX setup for anyone.

I have a dedicated track wheel/tire set, but sometimes I’m not able to transport them so I just run on my daily 4S OEM wheelset. Does great, minus some slight fender liner rub in the front.

I’m halfway contemplating 255/285 for my daily/occasional track set. I’m guessing times wouldn’t be any different, and there would be less shoulder wear and rub. Also guessing there would be a slight understeer increase, tho.

Last edited by ZM2; 12-30-2017 at 06:57 PM..
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      12-29-2017, 05:47 PM   #43
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Quote:
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Quote:
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Right, and with camber plates too, I presume given the amount of front camber you are getting.
Yeah, Dinan suspension and Vorslag plates.

The sidewall isn’t as stiff on the PS4 vs RE-71R or R888R, and it does roll over a little. Grip and feel is still good tho.

If you ran a 265 PS4 on a 9” OEM wheel exclusively for AutoX, I do think you would wear the shoulder off before the rest of the tire, even with -2.7 camber. But, I’m doubting this will be a pure AutoX setup for anyone.

I have a dedicated track wheel/tire set, but sometimes I’m not able to transport them so I just run on my daily PS4 OEM wheelset. Does great, minus some slight fender liner rub in the front.

I’m halfway contemplating 255/285 for my daily/occasional track set. I’m guessing times wouldn’t be any different, and there would be less shoulder wear and rub. Also guessing there would be a slight understeer increase, tho.
Thanks for the feedback.

I'm thinking 255/275 RE-71s may be my starting point with this car, along with a front Dinan bar (and I'll put the rear bar I can't use in BS in the closet.) If 255/285 will result in more understeer (I think you're right about that), then backing off to 275 in the rear would restore the factory balance but with more grip from the RE-71s and a little more width. I'll run the stock 19s to save a little money. And I won't have clearance issues no matter how hard I push.

After the 2018 AX season, if I choose to go bigger, then the "perfect" Apex 9.5/10.5" 18 inch setup with coilovers, camber plates, and more tire with way more camber would be in order.
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      12-29-2017, 06:45 PM   #44
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Quote:
Originally Posted by jnoyes View Post
Thanks for the feedback.

I'm thinking 255/275 RE-71s may be my starting point with this car, along with a front Dinan bar (and I'll put the rear bar I can't use in BS in the closet.) If 255/285 will result in more understeer (I think you're right about that), then backing off to 275 in the rear would restore the factory balance but with more grip from the RE-71s and a little more width. I'll run the stock 19s to save a little money. And I won't have clearance issues no matter how hard I push.

After the 2018 AX season, if I choose to go bigger, then the "perfect" Apex 9.5/10.5" 18 inch setup with coilovers, camber plates, and more tire with way more camber would be in order.
That’s a great plan and exactly what I would do.

I also have Dinantronics Stage 1 and IC, so the 285s really help with rear grip and the added torque. I’ll probably do the 255/285 combo for the street and stick to my 265/35/18 square RE-71R setup for the track.

If I add more power in the future, I’ll get the same 9.5/10.5 setup you mentioned with more rubber.
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