Vmax tips??

[TTBear]

I have tried searching as much as possible regarding a definitive top speed for the M3, to no avail. It would appear that there hasn't really been a proven top speed, at least not that I could find.

Sooooo, assuming there was an organized event, run on a closed circuit (say, a runway), and speaking purely hypothetically, if one were to choose to participate in said event, what would one do in preparation?

-Increase tire pressure? I'm thinking the hypothetical participant might increase tire pressure to around 40psi front and rear.
-I (I mean, the hypothetical participant, herewith known as the "HP" ) have a DCT transmission - would VMax be achieved in 6th gear? It seems that in many posts, it is intimated that 7th gear doesn't cut it for VMax.
-Would this HP run with DSC on? I think he (or she) probably should - no benefit from this in a straight line, right?
-Assuming that the HP has 18 OEMs with PS2s, 19" OEMs with PS2s, and 20" HREs with Nitto Invos, what would be the best to use? I (errr, the HP - if such a thing exists, in this theoretical realm) have eliminated the HREs, as the rear tires, amazingly, are NOT Y rated! . So, any difference between the 18s and 19s?
-Anything ELSE this HP might want to consider?

Any guesses as to what he/she might achieve, given a, say, 2.4 mile runway?

The HP had considered reverting to all stock stuff, to try and determine the actual Vmax of a stock M3, but then decided it would be too much of a pain in the ass. So screw that. Hypothetically.

[Trier Germany]

Originally Posted by TTBear

I have tried searching as much as possible regarding a definitive top speed for the M3, to no avail. It would appear that there hasn't really been a proven top speed, at least not that I could find.

Sooooo, assuming there was an organized event, run on a closed circuit (say, a runway), and speaking purely hypothetically, if one were to choose to participate in said event, what would one do in preparation?

-Increase tire pressure? I'm thinking the hypothetical participant might increase tire pressure to around 40psi front and rear.
-I (I mean, the hypothetical participant, heretofore known as the "HP" ) have a DCT transmission - would VMax be achieved in 6th gear? It seems that in many posts, it is intimated that 7th gear doesn't cut it for VMax.
-Would this HP run with DSC on? I think he (or she) probably should - no benefit from this in a straight line, right?
-Assuming that the HP has 18 OEMs with PS2s, 19" OEMs with PS2s, and 20" HREs with Nitto Invos, what would be the best to use? I (errr, the HP - if such a thing exists, in this theoretical realm) have eliminated the HREs, as the rear tires, amazingly, are NOT Y rated! . So, any difference between the 18s and 19s?
-Anything ELSE this HP might want to consider?

Any guesses as to what he/she might achieve, given a, say, 2.4 mile runway?

The HP had considered reverting to all stock stuff, to try and determine the actual Vmax of a stock M3, but then decided it would be too much of a pain in the ass. So screw that. Hypothetically.

Do ED and break your car in properly here in germany. then you can go V-max and try it out. it seems the stock speedo is quite inaccurate. I have M-DCT and my speedos says 180 Mph in 6th at redline

[TTBear]

Originally Posted by Trier Germany

Do ED and break your car in properly here in germany. then you can go V-max and try it out. it seems the stock speedo is quite inaccurate. I have M-DCT and my speedos says 180 Mph in 6th at redline

I have already broken the car in. That seems to be the problem - I am reading "my speedo reads XXXmph", but nobody seems to know definitively what VMax is. The speedo error could be as much as 10%, so 180mph could be as 162 (which is pretty well at which the limiter is supposed to be set). Anyone can go out on the highway, nail it, and say "my speedo read 250mph", or whatever, but I'd really like to know ACCURATELY, what top speed actually is.
I would like to find out under controlled, electronically timed circumstances, what a delimited M3 will do. I have yet to read a post stating "I ran my car at had it timed by calibrated electronic equipment, at xxxmph".

I'm all for empirical data, and not anecdotal, inaccurate hearsay

[jdgamble]

Well the top speed limiter can be increased from 161 to 178 from the factory, and the Redline in 6th on DCT is 166, so you would have to be in 7th to achieve this speed. But since it's still limited, you could obviously get over 178. I'm thinking mid-180's should be the real top speed given unlimited road.

Oh - And I wouldn't increase tire pressure too much... I would imagine a temp increase at those speeds.

[Richbot]

There are already a couple vids out there of mildly modified (bolt-ons and software) E92's reaching 300kph on GPS, which is 186 mph.

[calintexas]

Pencil Geek would know about tires and pressures from his mile efforts.

As far as I know portable GPS units (such as Garmin's) are very accurate in providing your speed at a steady state. Most are said to update at one second intervals. Anecdotally, both of our current Garmin 765T's agree very well with mileage marker calculated speeds.

[TTBear]

Originally Posted by Richbot

There are already a couple vids out there of mildly modified (bolt-ons and software) E92's reaching 300kph on GPS, which is 186 mph.

Thanks - I have searched, but I was unable to find anything like this. Do you happen to have links to said vids?

Also, the main purpose of my post is to ask of others, what I might one might do in preparation for a VMax attempt.

I don't really want to go to extremes, such as taping up seams to decrease drag - just want to make things safe, with no surprises.

This should be fun. How many times does one get to go out on a track, and reach terminal velocity in their car (unless, of course, you are driving a 58hp Fiat Uno (my first car ).

300kph would be awesome. That seems to be the target for the day. Lots of cars will be WAAAAAY over that, methinks.

[Richbot]

There are a couple on youtube, search E92 M3 top speed and they're on there. Some of them rely on the in-dash readout, but there are a couple running around which had GPS as well, I found them during intense internet geekery for the many months before I found my car.

The manual has pressures which are recommended for use when the car is fully loaded and going to be traveling above 100mph (I love BMW...). I'd start with that. The tires are good for 51psi cold so it's not like starting at 40 is going to blow a tire.

Take a torque wrench and re-torque the wheels with a torque wrench after running at sustained high speeds, especially if you do a lot of braking. On the racecars it can take as many as 4 sessions before they quit loosening up due to vibration and heat expansion. Don't have to loosen them up and retighten them, just click them down again.

[piloto]

Why not just figure it out mathematically? Note the rpm you're in and the gear, look up the gear and final drive ratios, and calculate your tire diameter (you can do this easily with chalk and a tape measure). Then you can determine the exact speed and not have to wonder how inaccurate your speedometer is. I posted the formula in another thread maybe a couple of weeks ago.

[mike33176]

I ran the Florida Mile a few months ago, the runway is 2 miles long so(after a few runs), I kept it burried thru the mile untill just past the 1.5 mile marker and I saw 184mph on my digital speedo before braking. 2500 ft was plenty of room to stop the car without any issues.

[TTBear]

Originally Posted by Richbot

There are a couple on youtube, search E92 M3 top speed and they're on there. Some of them rely on the in-dash readout, but there are a couple running around which had GPS as well, I found them during intense internet geekery for the many months before I found my car.

The manual has pressures which are recommended for use when the car is fully loaded and going to be traveling above 100mph (I love BMW...). I'd start with that. The tires are good for 51psi cold so it's not like starting at 40 is going to blow a tire.

Take a torque wrench and re-torque the wheels with a torque wrench after running at sustained high speeds, especially if you do a lot of braking. On the racecars it can take as many as 4 sessions before they quit loosening up due to vibration and heat expansion. Don't have to loosen them up and retighten them, just click them down again.

Great tips. Thanks!!

Originally Posted by piloto

Why not just figure it out mathematically? Note the rpm you're in and the gear, look up the gear and final drive ratios, and calculate your tire diameter (you can do this easily with chalk and a tape measure). Then you can determine the exact speed and not have to wonder how inaccurate your speedometer is. I posted the formula in another thread maybe a couple of weeks ago.

So.... ummmmm...... where's the FUN in THAT?

Theoretical experience is all well and good, but at the end of the day, I'm kind of a hands-on type of guy. Empirical evidence is everything, to me at least - it negates the "armchair cowboy" factor.

What if your tach is out by a few percentage points? There would always be that niggling doubt, and I'd be wondering.... "how accurate is that, REALLY"?

Besides - how many times do you get to saddle up, get on a huge-ass runway, and just let rip?

And, it's all for a few great causes, too. Hard to beat that.

[TTBear]

I just watched a couple of youtube vids. One had a BMW test driver maxing out the M3. He had 250kg of ballast in the trunk.

Anyone think this is necessary? I definitely don't want the rear end getting light around 170mph.

[klammer]

^+1
this car is all about visceral experience, not math (at least driving it that is, don't want to piss off the engineers, we love you) anyway, where is this "hypothetical event" taking place and when, always looking for an excuse to road trip it. pm me if you want to maintain hypothetical status. cheers

[TTBear]

Originally Posted by klammer

^+1
this car is all about visceral experience, not math (at least driving it that is, don't want to piss off the engineers, we love you) anyway, where is this "hypothetical event" taking place and when, always looking for an excuse to road trip it. pm me if you want to maintain hypothetical status. cheers

LOL. It's not really a big secret. I was just messing around.

"Race the Base" - Cold Lake, Alberta. There's a Canadian air force base there. There will be some pretty crazy rides there. (Fastest Enzo in the world, twin turbo Gallardo, etc., etc.)

Linky poo:

http://www.zrauto.ca

Proceeds to several very worthy causes.

Should be fun. I'm going to be one of the slow guys , but it will be no less fun for me.

I think there are a few spaces left over, if you'd like to drive up from Chi-town, LOL

[piloto]

Originally Posted by TTBear

Great tips. Thanks!!




So.... ummmmm...... where's the FUN in THAT?

Theoretical experience is all well and good, but at the end of the day, I'm kind of a hands-on type of guy. Empirical evidence is everything, to me at least - it negates the "armchair cowboy" factor.

What if your tach is out by a few percentage points? There would always be that niggling doubt, and I'd be wondering.... "how accurate is that, REALLY"?

Besides - how many times do you get to saddle up, get on a huge-ass runway, and just let rip?

And, it's all for a few great causes, too. Hard to beat that.

Dude, read my post again. Where am I telling you to calculate it theoretically? I'm not. Man, people on here glance through a post and run to conclusions.

What I'm telling you is, here it is in bold, when you drive at top speed, look at the RPM. Then, after you're done with your run, you can determine, by simple math, what your actual, real vmax was.

[piloto]

Originally Posted by klammer

^+1
this car is all about visceral experience, not math (at least driving it that is, don't want to piss off the engineers, we love you) anyway, where is this "hypothetical event" taking place and when, always looking for an excuse to road trip it. pm me if you want to maintain hypothetical status. cheers

[klammer]

Originally Posted by piloto

i was told there would be no math...

[klammer]

Originally Posted by TTBear

LOL. It's not really a big secret. I was just messing around.

"Race the Base" - Cold Lake, Alberta. There's a Canadian air force base there. There will be some pretty crazy rides there. (Fastest Enzo in the world, twin turbo Gallardo, etc., etc.)

Linky poo:

http://www.zrauto.ca

Proceeds to several very worthy causes.

Should be fun. I'm going to be one of the slow guys , but it will be no less fun for me.

I think there are a few spaces left over, if you'd like to drive up from Chi-town, LOL

guess i was hoping it was by toronto, going to the track that weekend but would love to do something like that. have fun, drive safe

[TTBear]

Originally Posted by piloto

Dude, read my post again. Where am I telling you to calculate it theoretically? I'm not. Man, people on here glance through a post and run to conclusions.

What I'm telling you is, here it is in bold, when you drive at top speed, look at the RPM. Then, after you're done with your run, you can determine, by simple math, what your actual, real vmax was.

Wow. Dude - please - I mean to create no angst, here. Don't get your knickers in a twist. Please, read MY post again. I guess I wasn't really clear. Sorry. What I was inferring, was that there is an inherent margin of error, not only in the speedometer, but also, the tachometer - a much, much greater margin of error than would exist in an electronic timing device measuring the exact speed of the car.
As well, if I'm going around 290 to 300kph, I'm not going to want to be looking down at a (potentially erroneous) tachometer.
As well, measuring the diameter of my tires is fraught with potential error. At that speed, the diameter of the tire is going to change, as compared to a tire that is static. Unless, of course, you know of an awesome way to get out and measure the diameter when you're driving 290kph or so.

Ok, sorry - little bit facetious, there.

I did misread your post. Apologies. No need to be Michael Douglas in "Falling Down".

I would just prefer to bomb down a runway, have my speed measured EXACTLY, with no (or a minimal) margin of error, safely.

'kay?

So... can ya help me out with how to do this safely, and contribute to my post? Cheers!

[piloto]

Damn, you Canadians are too nice. Probably why you don't go to war often.

Your tach is pretty accurate. But the best way is going to be via GPS, as others have said. I would suggest hooking up two different GPS units if you can, as well as using the method I described above using your RPM, and that should help narrow it to a very close number. To be abosultely perfect, you'll need a highly accurate GPS that you would have to calibrate for altitude.

[Jimmer]

Originally Posted by TTBear

LOL. It's not really a big secret. I was just messing around.

"Race the Base" - Cold Lake, Alberta. There's a Canadian air force base there. There will be some pretty crazy rides there. (Fastest Enzo in the world, twin turbo Gallardo, etc., etc.)

Linky poo:

http://www.zrauto.ca

Proceeds to several very worthy causes.

Should be fun. I'm going to be one of the slow guys , but it will be no less fun for me.

I think there are a few spaces left over, if you'd like to drive up from Chi-town, LOL

I was SO upset as I was asked to instruct this event but was already booked with another track event. Should be fun!

[E90M3CDFR]

Originally Posted by TTBear

I have tried searching as much as possible regarding a definitive top speed for the M3, to no avail. It would appear that there hasn't really been a proven top speed, at least not that I could find.

Using GPS (in my case separate units - a Garmin, a Coyote, and the GPS in my Blackberry...all reading identically once they "settled"), I've found the top end of a 2009 M3 with DCT to be between 261-268km/h...meaning that on different stretches of autobahns there was some variation. If you have the M-Driver package that is available only on European-spec M3s, the limiter is raised to 280km/h.

The M3 tire pressures provide two ranges for speeds below/above 100mph(160kmh), but if the car is not heavily loaded, I believe the pressures are the same regardless (35psi/36psi), but most folks would likely advise to add some additional air for extended high speed runs even if with a light load.

Compared to some other cars I've driven regularly on the autobahn, the M3 feels a bit light at over 140mph; that said, its quite stable and easy to modulate the breaking from that speed (ie not much need to counteract side/side motion etc). I find it easier to drive at these speeds with EDC set to normal. Sport setting makes the car feel more nervous -- whether that is true in fact, ie if I had to brake/avoid something I cannot say for sure. Comfort setting also felt a bit too loose.

I've been curious about whether the larger lip spolier that you can buy now from M Performance would address some of this (in my case perceived) lightness of being at speed.