[MKSixer]

Originally Posted by CanAutM3

Just as a small precision though, because of the rearward weight transfer that occurs during acceleration, doubling the "contact area" with AWD will not double traction. I agree that AWD will yield a much better launch, however it will hamper acceleration at speeds where traction is not an issue due to increased weight and drivetrain losses.

The i8 does not suffer from these losses as there is no coupling between the two sets of driven wheels.

[CanAutM3]

Originally Posted by MKSixer

The i8 does not suffer from these losses as there is no coupling between the two sets of driven wheels.

Agreed about the drivetrain losses, however the i8 still suffer from the extra weight of electric motors and batteries. The i8 gets a good quarter mile ET because of its great launch (electric motors produce max torque at zero RPM). However, its trap speed is rather un-impressive. Pit the M4 and i8 in a roll race, and the i8 does not stand a chance.

However, as I posted previously, Scott26 hinted that e-boost is in the future for M cars. It will be interesting to see how it pans out .

[V1.47fan]

Originally Posted by CanAutM3

The wing isn't there to improve launch traction. It's there to improve cornering at high speed.

+1

To the 60ft point, a wing hardly creates any downforce...

[MKSixer]

Originally Posted by CanAutM3

Agreed about the drivetrain losses, however the i8 still suffer from the extra weight of electric motors and batteries. The i8 gets a good quarter mile ET because of its great launch (electric motors produce max torque at zero RPM). However, its trap speed is rather un-impressive. Pit the M4 and i8 in a roll race, and the i8 does not stand a chance.

However, as I posted previously, Scott26 hinted that e-boost is in the future for M cars. It will be interesting to see how it pans out .

This entire thread confirms that keeping my E63 M6 is the best decision that I ever made. All of the complaining about the power delivery of the S85 and later, S65 comes down to one issue: Lack of driver training. I'm no Senna...Aryton or Bruno but I know how to keep the car in the meaty part of the power band during critical driving situations and I know that the flat spot in the S85 power band is between 2800 and 3200 RPMs. I only hit it one time when accelerating from a stop and never worry about it thereafter. If a person runs their S65 or S85 at less than 4500 RPMs on a regular basis and complains...they should get another car.

e-Boost would be perfect in the S85/S65...hmmmmmm.

[r3dbimmer89]

Originally Posted by PhoenixWolf

Everyone talking about how bad the M4 driver was. Thing is the average driver does not know how to drive so it sums it up as what to expect in the real world.

True, but I don't waste 5 minutes of precious time watching amateurs launch fast cars on YouTube...working for a publication, I expect the drivers to know what they hell they're doing

[Robert]

Come on guys it's just a video on the internet, even if it's no all factual, no need to get all upset over it. World is not ending

[Fundguy1]

Originally Posted by CanAutM3

Maybe because it does not have a turbo engine

That should be the opposite. A non turbo engine the power comes on out the gate. Turbo engines have some lag for power coming on. They should grip better at launch.

As for awd, the benefits at launch and handling far outweigh the detracting of the extra weight. Cases in point Nissan GTR, Mitsubishi EVO, Subaru WRX, etc, etc, etc. I think BMW has decided to stay rwd because it's traditional the same way they kept the 6 series convertible a soft top and rumor has it they're switching back to soft tops on 4 series next generation. Yet they decide to purge manual transmissionso and LSDs from their standard lineup and entrance electrics and hybrids. All bad calls as far as I'm concerned.

They should have AWD, hardtops, LSDs, and MT available for all Ms and most non-Ms. Screw the electrics.

[CanAutM3]

Originally Posted by Fundguy1

That should be the opposite. A non turbo engine the power comes on out the gate. Turbo engines have some lag for power coming on. They should grip better at launch.

Not quite.

See my earlier reply: http://f80.bimmerpost.com/forums/sho...&postcount=108

[Fundguy1]

Originally Posted by CanAutM3

Not quite.

See my earlier reply: http://f80.bimmerpost.com/forums/sho...&postcount=108

I agree on the gearing but I was replying specifically to the gaf on turbos vs v8s. Gearing being equal a turbo should hook easier. Yes, fix the gearing. Lots of guys choose to launch in 2nd at this point. Where's our launch mode?

[CanAutM3]

Originally Posted by Fundguy1

I agree on the gearing but I was replying specifically to the gaf on turbos vs v8s. Gearing being equal a turbo should hook easier. Yes, fix the gearing. Lots of guys choose to launch in 2nd at this point. Where's our launch mode?

I don't think turbo lag comes into play at all here.

For any launch, tire and/or clutch slip needs to happen to avoid the engine bogging or even dying.

For a most optimal launch, the tires and/or clutch need to slip long enough to meet the sweet spot where the tractive force supplied by the engine becomes superior than the force sustained by the dynamic coefficient of friction of the tires. The turbos are more than likely fully spooled at that point.

The challenge with a turbo engine such as the S55, is that it supplies so much torque low in the RPM, it makes it very tricky to manage that sweet spot. The fact that it also has a ridiculously low 1st gear only exacerbates the problem.

Just to doodle with numbers a little, as low as 1850RPM, an S55 with DCT pushes ~6755 lb-ft of torque to the rear wheels (406lb-ft x 3.462 x 4.806). Lets assume an arbitrary (and exaggerated) 15% drivetrain loss, this translates to ~5185 lbf of tractive force (6755lb-ft x 0.85 / 1.107ft). Even assuming 100% weight transfer (which will never happen) to the rear wheels on a 3700lb car with driver, that means the tires would need to have a 1.4 coefficient of friction to avoid spinning. That will never happen with street tires.

[Kiety]

As much as the M4 is a nice car the RC-F sounds 10x better. For an average driver on public roads any of these cars are more car than anyone could ever use.

[Pyrat 2]

if you're going to have a goofy comparison like this then leave all the nannies on in all the cars and just hit the gas and go. would be interesting to see the results in that scenario. looks like the putz driving the m4 thought he could disable traction control and smoke the competition. only thing he smoked was the tires.

[redux]

Originally Posted by Fundguy1

That should be the opposite. A non turbo engine the power comes on out the gate. Turbo engines have some lag for power coming on. They should grip better at launch.

[Fundguy1]

OK redux. That's how it is on my 335 vs my old vette. Turbos need more rpm to spool up. Vette was a monster from the start.