[infoage1]

Look how Ducati got 996cc's out of the S4R. It looks to be more a bored and stroked 916, than a 996 engine. Wonder if they have the smaller 916 head/valves and short intake S4/ST4s cams?

WTF?

------------------------------------------------------------------------
DUCATI MS4

Type L twin cylinder, 4 valve per cylinder Desmodromic; liquid cooled
Displacement 916 cc
BorexStroke 94x66 mm Compression Ratio 11:1
Power 74 kW - 101 HP @ 8750 rpm
Torque 92 Nm - 9,3 Kgm @ 7000 rpm
Fuel injection Marelli electronic fuel injection, 50 mm throttle body
Exhaust 2 aluminium mufflers
Emissions Euro 1

Transmission
Gearbox 6 speed
Ratios 1st 37/15, 2nd 30/17, 3rd 28/20, 4th 26/22, 5th 24/23, 6th 23/24
Primary drive Straight cut gears; Ratio 1.84
Final drive Chain; Front sprocket 15; Rear sprocket 37
Clutch Dry multiplate with hydraulic control

-------------------------------------------------------------------------
DUCATI S4R ENGINE

Type L twin cylinder, 4 valve per cylinder Desmodromic; liquid cooled
Displacement 996 cc
BorexStroke 96x68.8 mm
Compression Ratio 11.6:1
Power 83.4 kW - 113 HP @ 8750 rpm
Torque 95.5 Nm - 9,68 Kgm @ 7000 rpm
Fuel injection Marelli electronic fuel injection, 50 mm throttle body
Exhaust 2 aluminium mufflers

Transmission
Gearbox 6 speed
Ratios 1st 37/15, 2nd 30/17, 3rd 28/20, 4th 26/22, 5th 24/23, 6th 23/24
Primary drive Straight cut gears; Ratio 1.84
Final drive Chain; Front sprocket 15; Rear sprocket 35
Clutch Dry multiplate with hydraulic control

----------------------------------------------------------------------
DUCATI 996 ENGINE

Type L twin cylinder, 4 valve Desmodromic, liquid cooled
Displacement 996cc
BorexStroke 98x66mm
Compression Ratio 9.2:1(996)
HP 82kW - 112 HP @ 8500 rpm
Torque 93 Nm - 9.5 Kgm @ 8000 rpm
Fuel system Marelli Electronic Injection, 50 mm throttle body
Exhaust 2 aluminium mufflers by Termignoni

Transmission

 

[Speeddog]

Re: S4/S4R/996 Engines

If I had been thinking about it, I would have looked closer at the S4R bikes on our ride yesterday.

From the pictures I have, the S4R doesn't have the low exhaust cam position of the S4 / ST4.

S4R engine has peak HP and peak torque at the same RPM as the S4, but doesn't have much more torque. That means it's breathing better past the torque peak. Maybe the higher cams/better exhaust ports and exhaust system are the factors.

BTW, the S4R has the wide ratio tranny. The ducati.com spec sheet is incorrect, from what one owner reported on his rpm - speed readings in 6th gear.

 

[Speeddog]

Re: S4/S4R/996 Engines

I imagine the performance increase potential is almost as good on the S4R as it is on the S4. The only holdup may be that it could be difficult to make the engine any bigger, as it appears to be an enlarged '916'. May not be any room for bigger pistons.

Only other thing that comes to mind is there may be fewer hotrod parts if the motor is totally exclusive to the S4R, just due to small production numbers.

I just assumed it was a 996 motor like what's in the ST4S....

 

[infoage1]

Re: S4/S4R/996 Engines

because I understand little of what you two gear heads are saying I'll skip to the question...does what you're saying

 

[infoage1]

Update:

Brad Black from Moto One checked part numbers. He found that the SR4 and the ST4s share the same part numbers for crank, rods, pistons and cylinders. The part numbers for the heads were different, but he didn't think that meant much.

So, it looks like the S4R has a 'true' 996, with a 98mm bore x 66mm stroke. The information on ducati.com appears to be a strange typo (the math even works out).

http://www.ducati.com/docs_eng/promo/scoop_page/scoop_page023/popup/motore.jhtml


http://www.moto-one.com.au/performance/

 

[chris]

68.8 stroke? hmmm. wierd. that must really drop the redline. the 904s with their 68mm stroke are 9000 rpm.

coool... need to update the calculator...

 

[Speeddog]

OK, so it's a ST4S / 996 motor after all.
I was wondering WTF Ducati was doing........

In conclusion, they botched the bore & stroke, as well as the tranny ratios on the S4R tech data. I guess the proofreader's been hittin' the Chianti pretty hard. ;D