Randy Pobst hot laps the 2016 BMW M4 GTS for Motor Trend Best Driver's Car 2016

[CanAutM3]

Originally Posted by Captain Unknown GT4

I just try to explain to you the auto bild text. You might try Google translate to get the ide about their impressions.

BTW, I am fluent in German . Please just point to the Auto Bild article passage you refer to, because the only comment I can find in the article about the tires' impact on acceleration is about the extra grip from the Cup tires for the 0.4sec improvement to 100km/h relative to the base M4; no mention about wider tires... maybe I missed it .

[redux]

Originally Posted by Billj747

They both run Cup2s. If you were referring to the same width, then I'd counter that with taking weight out of the 350R to be the same as the GTS and moving the heavy battery to the trunk to improve weight distribution like the GTS...

Cup 2's are not all created equally. The 350r Cup 2's are a superior compound to the others.

[BarryB]

Originally Posted by Obioban

To be a fair test, you need the same tire pressures in each and tires at the same point in their life cycle.

... and you should watch your instructor, to make sure he's within a tenth or two from one lap to the next, given the same hardware...

Not jumping into this mess but since there is a comment referring to a test, FYI I was there for one of the days and these tests don't even come close to meeting scientific rigor. Randy is also coached in what to say to camera/ interviewer, btw. Several re-takes too.
Also anyone who's been to the Bay Area can attest to huge temp variation between am's and pm's. So even on the same day you would not be surprised to see a 20 degree F difference.
See pics and comments on another thread here from that day.

[Billj747]

Originally Posted by adc

Well going from 265/285 to 305/315 will have a much bigger impact than taking out 50-100lbs from the car. IMO.

Matter of fact I may test that assumption next time I'm at the track, if I can find an instructor willing to jump in for a few laps.

If you equal the tire, you should equal the weight (~350lbs). If not then the GTS should only get 275/295s.

Originally Posted by redux

Cup 2's are not all created equally. The 350r Cup 2's are a superior compound to the others.

Very true they are not all created equal, but the 350Rs Cup2s are by no means the most aggressive Cup2 -that would probably belong to the Z06. I can probably find out from Michelin how aggressive the GTS' Cup2s are but knowing how conservative the 350Rs tires are (oh, and they are on the narrow side of a 305 & 315) -i think they are actually closer in spec than most would believe.

[bradleyland]

Originally Posted by Billj747

If you equal the tire, you should equal the weight (~350lbs). If not then the GTS should only get 275/295s.

Huh?

That's not the point of the comparison. You can easily swap tires/wheels. You cannot easily discard 350 lbs. The point is to determine whether the M4 GTS could achieve better results with larger tires.

Anyone else feeling like this thread is treading dangerously close to reductio ad absurdum territory on multiple fronts?

[Bucki14]

Hmmmm...when did I ever mention race car? I don't ever recall mentioning that. I simply compared this track car to other track cars in its class? But, yes I wont argue with the 10/10ths comments...yes very few people will be able to drive at 10/10ths and very few people will be able to exploit any of these cars maximum capabilities...But, at the end of the day as it stands in these given conditions with randy as the driver. The M4 GTS got beat and that is just that, so yes BMW did a shitty job beating its competitors with a higher budget (limited edition car). Now, as it stands it has a better ring time so at the end of the day unless I go out there a run better numbers around the track in car x vs y....this is all just magazine talk.

Originally Posted by bradleyland

There's a difference between a track car and a race car. A track car is something you take to the track and drive for enjoyment. A race car is built to turn competitive lap times for a given class.

Many HPDE and track day events don't allow timing, don't allow passing (except under specific circumstances), and sometimes enforce time-separation between cars. In these cases, if your car's maximum capability is 1-2 seconds per-lap off pace from other cars in your group, it doesn't really matter. Very few people are even capable of driving their car 10/10ths, and that kind of driving is discouraged. Typically, two wheels off, you get a warning. Four wheels off, and you're headed for the pits. Repeated offs and you're done for the day. Driving at 10/10ths, you're going to have offs.

Saying that BMW does a "damn shitty job" at building a track car is just laughably over the top. It's not like it turned a 1:40 lap.

[Billj747]

Originally Posted by bradleyland

Huh?

That's not the point of the comparison. You can easily swap tires/wheels. You cannot easily discard 350 lbs. The point is to determine whether the M4 GTS could achieve better results with larger tires.

Anyone else feeling like this thread is treading dangerously close to reductio ad absurdum territory on multiple fronts?

It would likely go faster with wider tires. And the 350R will go faster with less weight.

How much would a nice lightweight set of forgelines go for? $4K and $2K for tires? You can do a good amount of weight reduction for $6K.

It would be interesting to see how a GTS stacks up to the 350R on equivalent tires. I also wonder how much downforce it makes compared to the 350R (which is ~2X that of a Porsche GT3).

[bradleyland]

Originally Posted by Bucki14

Hmmmm...when did I ever mention race car? I don't ever recall mentioning that. I simply compared this track car to other track cars in its class? But, yes I wont argue with the 10/10ths comments...yes very few people will be able to drive at 10/10ths and very few people will be able to exploit any of these cars maximum capabilities...But, at the end of the day as it stands in these given conditions with randy as the driver. The M4 GTS got beat and that is just that, so yes BMW did a shitty job beating its competitors with a higher budget (limited edition car). Now, as it stands it has a better ring time so at the end of the day unless I go out there a run better numbers around the track in car x vs y....this is all just magazine talk.

I never said you said... Jesus, this is getting ridiculous. Let me start over.

I never said you mentioned race cars. I used the comparison between the priorities of a race car and the priorities of a track car to make a point. The point being that lap times tell you a cars performance, but performance alone isn't what defines a good track car.

If all you care about is performance per dollar, then by that criteria, the M4 GTS is a pretty horrible car. No argument there. I think that's a pretty narrow view though (unless you're racing). And if you're really after performance per dollar, cars like the Corvette is hard to beat. It destroys the GT350R. Did Ford make a "shitty" car too?

The point being, making vehicle comparisons on a single-dimensional basis is a daft thing to do. Lots of people do it, but it's still silly. Doesn't matter if it's 0-60, 1/4 mile time, or lap time around a particular circuit. There's more to it than that. As you said, "this is all just magazine talk".

IMO, what's important in a track car is how enjoyable it is to drive around a circuit.

- A track car is no fun if it plows through corners like a truck.
- A track car is no fun if it spins every time you touch the accelerator.
- A track car is no fun if the steering is unresponsive.

Notice that none of those can be measured by lap time?

A slow car with good balance, a responsive throttle, and great steering will be more enjoyable around a track than an understeering pig with 700 HP and the hydraulic rack out of 1983 Monte Carlo.

Originally Posted by Bucki14

But, at the end of the day as it stands in these given conditions with randy as the driver. The M4 GTS got beat and that is just that, so yes BMW did a shitty job beating its competitors with a higher budget (limited edition car).

The lap times are what they are. But you didn't qualify your statements in your original post. Seems like you're really reaching to cram "shitty" in to that post, btw. You said:

"The car is screaming with I'm a track BMW and well does a damn shitty job at it"

Give that a second or third read through and ask yourself, "Can I blame this guy for misunderstanding me?"

I'll admit, I could barely parse it, but I read that to mean the M4 GTS is a shitty track car. I'm not sure what else I was supposed to take from that.

[Obioban]

To be fair, this test was not "fastest track car", it was "best driver's car"-- an on that test (driver's car, which factors in how the car drives and how fast it is) the M4 GTS got second from last...

[bradleyland]

Originally Posted by Billj747

It would likely go faster with wider tires. And the 350R will go faster with less weight.

And if a frog had wings, it wouldn't bump its ass. Again, not really the point though.

The question is whether or not the M4 GTS would turn similar lap times on similar tires?

Originally Posted by Billj747

How much would a nice lightweight set of forgelines go for? $4K and $2K for tires? You can do a good amount of weight reduction for $6K.

Can you? It depends on the car. On a car that has already had weight reduction done at the factory, it is one of the most expensive things you can do. At least if your target is dropping 350 lbs. The GT350R already has no back seats and uses carbon fiber wheels. I don't get the sense that Ford left a lot of low-hanging fruit there.

The GT350R curb weight is 3,650 lbs. The GT350R-C (race car) weighs 3,350 lbs. So, in the process of making it a race car (no interior, no sound insulation, etc), they saved 300 lbs. How many people are going to go to that extreme?

Originally Posted by Billj747

It would be interesting to see how a GTS stacks up to the 350R on equivalent tires. I also wonder how much downforce it makes compared to the 350R (which is ~2X that of a Porsche GT3).

I'm curious if you have a source for the ~2X downforce claim. I've read that it produces "more" downforce than the 911 GT3, but none of the manufacturers are very specific when it comes to downforce. Just curious if you have a good source there.

[Billj747]

Its everywhere if you do a search:

http://www.topgear.com/car-reviews/f...0r/first-drive

http://www.motortrend.com/cars/ford/...-drive-review/

http://www.mustangandfords.com/featu...350r-mustangs/

The 350R-C has a dry sump, cage, fuel cell, and a few other items that add weight to the car. Plus about 100lbs of lead to meet the BOP weight requirements to slow it down. With some carbon panels it can be quite a bit lighter (I'm pretty familiar w.the car). For the 350R, It wouldn't be too hard to pull out 100lbs for well under that $6K it would cost to get wider wheels and tires for the GTS. With 100lbs less weight I would have a lot of confidence the 350R will still be faster than a GTS with 305/315 tires.

[bradleyland]

Originally Posted by Billj747

Its everywhere if you do a search:

http://www.topgear.com/car-reviews/f...0r/first-drive

http://www.motortrend.com/cars/ford/...-drive-review/

http://www.mustangandfords.com/featu...350r-mustangs/

The 350R-C has a dry sump, cage, fuel cell, and a few other items that add weight to the car. Plus about 100lbs of lead to meet the BOP weight requirements to slow it down. With some carbon panels it can be quite a bit lighter (I'm pretty familiar w.the car). For the 350R, It wouldn't be too hard to pull out 100lbs for well under that $6K it would cost to get wider wheels and tires for the GTS. With 100lbs less weight I would have a lot of confidence the 350R will still be faster than a GTS with 305/315 tires.

I could see trimming 100 lbs if you get aggressive. I was thinking of trying to drop the 350 lbs required to hit the M4 GTS curb weight. I think that would require serious dedication.

The good news is, I think we'll get a chance to see both cars in some pretty wild configurations, because the owners of both the M4 GTS and the GT350R appear to be interested in putting them to good use.

Personally, I'm a bigger fan of the GT350R. There's just something about that car that speaks to me... I mean screams to me. And I think it might be the Voodoo V8 at 8k RPM

[adc]

Originally Posted by Billj747

With 100lbs less weight I would have a lot of confidence the 350R will still be faster than a GTS with 305/315 tires.

And why exactly is that? Just curious, not argumentative.

Similar weight, power, and grip.

[Billj747]

Originally Posted by adc

And why exactly is that? Just curious, not argumentative.

Similar weight, power, and grip.

Just my feeling having tracked both and would have to say the 350R subjectively feels like it has more downforce and rear mechanical grip.

[Bucki14]

Originally Posted by bradleyland

"The car is screaming with I'm a track BMW and well does a damn shitty job at it"

Give that a second or third read through and ask yourself, "Can I blame this guy for misunderstanding me?"

I'll admit, I could barely parse it, but I read that to mean the M4 GTS is a shitty track car. I'm not sure what else I was supposed to take from that.

I didn't want to quote the whole thing...but touche on that. I can't argue with anything you stated and agree with it. Ultimately the car has to give the confidence to drive fast as well and that falls under the the characteristics of a car that can't be judged by anyone but the driver.

I guess ultimately for me I know BMW could have done just a bit better making it a full package, tires being one of them. I guess I want them to be crushing all records like they used to