[M4TW]

Originally Posted by FogCityM3

The S55 or other TC engines are not what the M-Division originally intended to produce. There are direct quotes from the former (yes, former and now 'retired') management at M who said stated they will never go forced induction.

Why didn't they want to produce a TC/FI M engine? Is it because they are anti-power and torque? Is it because they don't want cost savings? Or is it because in motorsport applications a linear power curve and instant throttle response are highly desirable characteristics due to throttle control and smooth application. Ever drive a TC vs and NA car on the track? I know what I prefer and we can also surmise that they didn't say this stuff just to be controversial.

No one will know the answer, but I'm willing to bet that the development of the S65 and S85 probably were at very little to no profit per vehicle. This is about emissions and cost savings and if you don't believe it, just look at BMW's own investor presentations and conferences, particularly the ones from 4-5 years ago. That is what has been driving all the decisions at the company. Linear power curves and instantaneous throttle response didn't make the investor powerpoints.

Cylinder de-activation, more aggressive/flexible cams, direct injection, better ECU coding, variable plenum sizing, higher displacement, lower mass on engine/transmission parts, gear skipping, rpm limits on eco modes can easily wring 460-470 bhp on the top end and improve fuel economy. Also, with proper gearing at least 420 bhp on the downshifts could be achieved, thereby equaling or surpassing the S55 performance wise. Yes, the new M3/4 is faster than its predecessor, but I'm still not at all convinced this is the best BMW could have given us for this price point (and keep their profit margin the same as with the S65, ie lower than what they are getting with the S55, as this is their Halo car.. they have plenty of other high volume applications to exercise their greed). A higher hp N/A car would have been ideal and would have made the decision of getting the new one vs keeping mine a no-brainer.

A high TQ number (to the crank) is so overrated, especially on the track. You get a little more speed exiting corners, but for a broad powerband range for the S65, any shortcoming on that front is more than made up with the powerband breadth, top end speed, and smooth throttle application. I see this over and over again against N/A and TC cars on the track. Especially for amateurs like myself, throttle control and not disrupting the chassis is so important, that the S65 is already pretty much perfect and tuned/improved to the order of 450-470 bhp would have been the ideal solution IMO. I have driven the 1M on the track and way too lumpy/punchy power delivery for my taste. Know the S55 improves on this, but unless physics can change how fast air molecules can travel, there will always be turbo lag or lack of initial response to changes in throttle application and power delivery will not be as linear.

So .... 460-470 bhp on the top end, improved fuel economy, 420 bhp on the downshift, and all for the same price eh?!?!

Well ... Hot Dog ... sign me up!!!!

Are you kidding me? I would LOVE an engine like that in my M4. Imagine, a more fuel efficient engine cranking out that many horses in a high revving, sweet sounding V8. My M4 would haul ass like nobody's business and there would be no worry about any of the drawbacks associated with lazy-assed turbo charging!!!

It just sounds too good to be true. So I'm not buying it. Literally. I'm not buying it. It's not an option for my M4 because it doesn't exist. It doesn't exist I suspect because the Dream Engine that you are describing is likely neither realistic nor feasible, or it would have been built by the engineering masters over in the ///M Division. But you know more than they do I guess.

Instead the path you are describing - considering that the platform is not being built by a division with an unlimited budget for buyers with unlimited budgets - likely would lead to a thirstier engine with modest performance gains that would be put to shame by the new S55.

Lest you think that the previous model's throttle response and power delivery was the Shangri-La of motorsport consider this Motor Trend article pitting your vaulted M3 against a standard-issue Mustang:

http://www.motortrend.com/roadtests/...m3_comparison/

So, shockingly good on the road course, but enough to beat the M3? Perhaps, because the first thing out of Randy's mouth after lapping the BMW is, "I missed the mid-range torque of the Mustang. The BMW ramps up more slowly and is skewed toward high rpm whereas the Mustang has a much broader, flatter torque curve."

Ouch.

The new IS-F is supposedly coming out with a 5.0 liter NA V8. It will have north of 400 horses, but they are not saying how much. Perhaps it might be a better metric of what might have been.

Time will tell.

Meanwhile, I will be enjoying all that lovely torque on tap and you can hug your e90 M3.