2015 F80 M3 vs. C63 S AMG and ATS-V instrumented comparison test by Car and Driver

MachinesWithSouls · 08-22-2015, 10:25 PM

Quote:

Originally Posted by rjd598

"It’s also the loudest car, the inline-six crescendoing at its 7500-rpm redline with a glorious racing rasp augmented by a subtle bass line from the stereo system. We pulled the radio fuse, No. 123 on the electrical box in the trunk incidentally, to see how the M3 sounds sans electronics. It sounds tough, though with some of the tinniness of the E46 M3 that, with the fuse back in, gets softened."

inb4 everyone complains about sound again.

In comparison to this group it's great.

CanAutM3 · 08-24-2015, 10:33 AM

Quote:

Originally Posted by solstice

It's also the difference between doing a handful lap in a car and owning it. It's like a pair of jeans or hiking boots, it takes a while to make person and equipment in sync. I agree with you as to that the F8X feel like it's putting down way more power than the E9X and the grip is superb but it also has way more power on tap at the mid range and will punish a lead foot. However it is more neutral where the E9X liked to under steer the F8X is more balanced and when it let go it's quicker and with more force.

The F8X definitely requires some getting used to. With my E92, I very quickly became comfortable with it. The car was very predictable and easy to drive fast from the get go. Not quite the case with my F82. I needed a good ten track days before I got fully comfortable. The first days, my forearm and buttock muscles would feel tense after a session. I was clearly not relaxed when driving. I also had to considerably re-calibrate my right foot. At my local track, there is a long right hand sweeper that has a moderate crest and dip in it. I could take it flat out with my E92. Not the case with the F8X where I got it seriously sideways at 110mph. A little unnerving to say the least

.

But now I have finally achieved symbiosis with the car. My body muscles are fully relaxed while driving and have re-calibrated my reflexes to the power delivery. I find the car very predictable and enjoyable to drive. I still find it need more rubber in the rear to fully exploit the S55 early power delivery coming out of corners and can't wait for APEX to release the their 18x11 wheel (hint-hint

)

solstice · 08-24-2015, 10:55 AM

Quote:

Originally Posted by CanAutM3

The F8X definitely requires some getting used to. With my E92, I very quickly became comfortable with it. The car was very predictable and easy to drive fast from the get go. Not quite the case with my F82. I needed a good ten track days before I got fully comfortable. The first days, my forearm and buttock muscles would feel tense after a session. I was clearly not relaxed when driving. I also had to considerably re-calibrate my right foot. At my local track, there is a long right hand sweeper that has a moderate crest and dip in it. I could take it flat out with my E92. Not the case with the F8X where I got it seriously sideways at 110mph. A little unnerving to say the least

.

But now I have finally achieved symbiosis with the car. My body muscles are fully relaxed while driving and have re-calibrated my reflexes to the power delivery. I find the car very predictable and enjoyable to drive. I still find it need more rubber in the rear to fully exploit the S55 early power delivery coming out of corners and can't wait for APEX to release the their 18x11 wheel (hint-hint

)

Sideways at 110mph...bet you could sharpen a pencil with your rear end

Will you make the 18x11s part of a dedicated track set with track rubber or run them on the street as well? The car is now so capable that it kind of deserves a track set. I would think driving to and on the track on the same tires is now quite a compromise, more so than ever.

CanAutM3 · 08-24-2015, 12:27 PM

Quote:

Originally Posted by solstice

Sideways at 110mph...bet you could sharpen a pencil with your rear end

Will you make the 18x11s part of a dedicated track set with track rubber or run them on the street as well? The car is now so capable that it kind of deserves a track set. I would think driving to and on the track on the same tires is now quite a compromise, more so than ever.

I went with a 275-295/35R19 PSS setup on the OEM wheels. I have well enough grip for street use. That is the nice thing about the F8X, is that one of its biggest shortfalls compared to its competitors (traction), can easily be resolved

.

The APEX shod with 305/35R19 NT01 in the rear will be a track only setup.

:

solstice · 08-24-2015, 12:46 PM

Quote:

Originally Posted by CanAutM3

I went with a 275-295/35R19 PSS setup on the OEM wheels. I have well enough grip for street use. That is the nice thing about the F8X, is that one of its biggest shortfalls compared to its competitors (traction), can easily be resolved

.

The APEX shod with 305/35R19 NT01 in the rear will be a track only setup.

:

Yes with compromise I meant for the track, even the stock setup is IMO more than good enough for the street but at the track you obviously want to be able to get maximum speed and track rubber should do more good than adding width, both is of course even better. It's interesting that the GTS runs on only one size wider at the rear. The wing must be good. Those 305s look perfect on the M4. I'll likely go 295s on stock rims as you when I need new tires but to be perfectly honest it would be mainly for the look since what is gained in the dry is lost in the wet and it's not unusual with some rain here

CanAutM3 · 08-24-2015, 12:51 PM

Quote:

Originally Posted by solstice

Yes with compromise I meant for the track, even the stock setup is IMO more than good enough for the street but at the track you obviously want to be able to get maximum speed and track rubber should do more good than adding width, both is of course even better. It's interesting that the GTS runs on only one size wider at the rear. The wing must be good.

You should not be fooled by the tire section width. The 285/30R20 PSC2 could well have a contact patch much wider than the 10mm suggest. For instance, the contact patch on my rear 295 is 43mm wider than the stock 275. Quite more than the 20mm section width increase.

solstice · 08-24-2015, 01:06 PM

Quote:

Originally Posted by CanAutM3

You should not be fooled by the tire section width. The 285/30R20 PSC2 could well have a contact patch much wider than the 10mm suggest. For instance, the contact patch on my rear 295 is 43mm wider than the stock 275. Quite more than what the 20mm section width increase.

Understood, still they could have gone wider but choose not to and I don't think it's due to cost

psedog · 08-24-2015, 01:31 PM

Quote:

Originally Posted by solstice

Understood, still they could have gone wider but choose not to and I don't think it's due to cost

MPG's. That's the only reason I could see.

solstice · 08-24-2015, 01:51 PM

Quote:

Originally Posted by psedog

MPG's. That's the only reason I could see.

Not impossible I guess but that would be really sad. Hopefully it's instead something like balancing the benefit of added grip with the negative of increased unsprung and rotational weight. If those new rims are really light it could feel difficult to add too much rubber and negate some of the hard work with a new light and strong wheel design.

CanAutM3 · 08-24-2015, 02:11 PM

Quote:

Originally Posted by psedog

MPG's. That's the only reason I could see.

I think wet grip is also another important factor. Since I moved to wider tires on my M4, the car is much more sensitive to aquaplaning.

psedog · 08-24-2015, 02:16 PM

Quote:

Originally Posted by CanAutM3

I think wet grip is also another important factor. Since I moved to wider tires on my M4, the car is much more sensitive to aquaplaning.

That's a good point. I hadn't thought of that.

Question, Why did you go to 275 in the front?

CanAutM3 · 08-24-2015, 02:19 PM

Quote:

Originally Posted by psedog

That's a good point. I hadn't thought of that.

Question, Why did you go to 275 in the front?

I wanted a setup that maintains the front-to-rear diameter stagger to not disrupt the DSC calibration. Also, at the limit, there is a significant amount of understeer with the stock 255. The 275 helped alleviate some of that. Further, my front 255s were corded after a 3 day track event and I needed to replace them. A simple fix was to move the rear 275 up front and install M5 295s in the back. See my thread on the topic:

http://f80.bimmerpost.com/forums/sho....php?t=1089535

solstice · 08-24-2015, 02:29 PM

Quote:

Originally Posted by CanAutM3

I think wet grip is also another important factor. Since I moved to wider tires on my M4, the car is much more sensitive to aquaplaning.

I definately think this is a big reason why we get 275s stock on the F8X but for the GTS I'm skeptical to it being a reason. The cup tires should be pretty scary in rain already with 285s. Again, not impossible though.

CanAutM3 · 08-24-2015, 02:37 PM

Quote:

Originally Posted by solstice

I definately think this is a big reason why we get 275s stock on the F8X but for the GTS I'm skeptical to it being a reason. The cup tires should be pretty scary in rain already with 285s. Again, not impossible though.

It is the reason we get VERY NARROWLY treaded 275s on the base M4. We don't know yet what the tread width will be on those 285/30R20 PSC2

.