A snippet from another thread (which I wanted here too, just fo reference).

For me the most important point regarding the B38 triple is that it is an undersquare engine. The stroke is almost 20% greater than the bore, which is not what most of us are accustomed to in a small displacement high performance engines.

Bore: 82 mm / 3.23 in Stroke: 94.6 mm / 3.72 in

The Japanese motorcycles have for years been oversquare, as have F1 engines since the 50s. They make power through high RPM, and provide relatively little torque because the stroke is modest, and therefore the length of the lever which is actually twisting the crankshaft (the throw of the crank journal) is pretty small. For example the Honda CBR engine released in 2009 (with 1 litre of displacement) has a bore and stroke of 2.95 in × 2.22 in. This motor makes about 150 HP, but has to spin to 12,000 rpm to reach that output. It has very little torque, making only about 75 ft/lbs at around 8,000 RPM.

In contrast, if I look at the Harley Davidson engines, which are justly regarded as torque monsters, the opposite approach is taken. THe engine in the 2013 Wide Glide has a bore of 3.88" but a massive stroke of 4.38". This is an undersquare engine, rated at about 100 ft/lb or torque at only 3,000 rpm. Amusingly, HD does not even state what the HP number is for this engine (at least not on the source I am using).

The R53 engine which I loved in the past peaked at around 162 ft/lb, and was rated at about 170 HP (at high RPM). The B38 engine which I am about to love actually has MORE torque than the "S" model did, based on the area beneath the curve, by which I mean that from 1,800 to 5,800 RPM the B38 has higher average torque than the "S" model did. Yet the B38 is rated at about 138 HP!

The reason for this is hiding in the realities (and mathematics) of horsepower and torque.

The bottom line is that I do believe that the F56 is going to be one hell of an effective G Street autocross car, because the torque curve will be not only greater than the DS R53, but also more equitably distributed across the rev range actually used in competition.

Also, I can only conclude that the B38 Mini application is significantly under-stressed which gives me hope for the mechanical longevity of the design. I think this due to the rather eye-popping numbers cited in the article which the OP linked at the start of this thread.

Cheers,

Charlie

 

be sure to flush the oil early on, and do the oil changes more frequently than with the dealer suggests, and probably with a high ZDDP oil! Turbo maintenance can be a bear, and you want to be careful, esp w a first year car! can't wait to see how this car does

 

Amen to that. This puppy is going to have a short oil change interval!

Cheers,

Charlie

 

good to hear. i flushed my oil on my '13 R56 at 500 miles, and that wasn't even the turbocharged motor. i'm getting great used oil analyses right now, and doing a comparo of a few different oils, each with ~50-60 autoxes and 2-3k miles. hope to post it all soon!

 

I'm looking forward to your info so I can make intelligent oil change decisions.

 

will do, will make a separate post when it happens. i'd always be sure to flush the oil within the first 1,000 miles just to get the wear out

 

kyoo you sound so old school - might be why i'm glad to have you around...



and look for fragments of brass in the leavings??



but of course i agree...

 

I have a vague recollection of reading (in the 50's I think) that engine wear was being reduced by shortening the stroke. Some discussions included the number of feet a piston traveled within the cylinder while driving the car a mile. The less travel would result in less wear. My cars, back then included air cooled Beetles and a PV544 Volvo.

Does that have any validity today? Or is the longer stroke a willing compromise for greater torque?

Yeah, I'm getting old.

 

haaa look forward to meeting at nats

 

Yeah I remember that too - and if I recall correctly there were two limiting factors at the time - both materials challenges that have since been overcome to a large degree.

One was the sheer force applied to the connecting rod which rose as a factor of both rpm and stroke. I remember mention of the number of tonnes of force required to change the direction of the piston and connecting rod at both tdc and bdc.

The other was ring technology at the time, which applied a limit to the maximum speed of the piston mid-way through the stroke.

The net effect of the two was a "you cannot have your cake and eat it too" rule, which prevented the combination of high stroke AND high rpm.

But technology has given us lighter and stronger, and so I rather suspect that designers have a larger conceptual space within which to devise their best recipe for an engine.

This sub-thread is getting kinda geeky (I like it).

Cheers,

Charlie

 

Well Gollum III will have wheels and tires waiting when he shows up.

Thanks to Turk from TireRack (sorry Alex, you were out brother).

Sparco Asiento Garo fits the bill, having the required 16x7 ET48 w/ 5x112 and a 66.5 mm center bore.

Black, visually appearing, and the lightest option available I think they'll do just fine.

And in the spirit of "more of the same" a fresh set of the R1R 205/45-16 to keep the rims off the ground.

Not the smartest choice in August, but by the time the Stirling Moss Trophy event comes around in autumn I'll be thanking myself.

So when they arrive I'll just stack them in the living room and wait for the car to show up.

Plus ca change, plus c'est le meme chose, n'est-ce pas?

Cheers,

Charlie

 

5 bolt pattern for wheels now? So none of the wheels out there will be interchangeable with the new MINI. Sorry, heavier, larger, and now other changes. Not sure this new MINI is staying in the spirit that MINIs were to be.

Not your fault, I know. I am sure you will over-enjoy your new purchase and looking forward to hearing how the new found torque benefits your endeavors

 

Indeed - would anyone like Mark Chiles' Panasports?

Still a brilliant wheel for the R56 - only lightly used on Sundays...

:-)

 

So now all I need is a car...



Cheers,

Charlie

 

Which, as of today, is awaiting transport!

"...
The children were nestled all snug in their beds,

While visions of sugar-plums danced in their heads

..."

Cheers,

Charlie

 

And is now departing for Halifax aboard the Independence, due in New York on the 9th.

Bon voyage!

Cheers,

Charlie

 

Excellent thread so far. Definitely going to be watching this one. Seems great minds think alike. Those Sparcos were next on my list. For my BRG Justa...

 

Birds of a feather?

 

And the ETA of the Independence at Halifax has slipped from the 7th to the 8th. I reckon the hurricane might have slowed their progress a mite...

Cheers,

Charlie

 

And the Independence is now due east of my position, in transit from Halifax to New Jersey. Perhaps if I get out the binoculars I might spot her...

Cheers,

Charlie

 

Great to hear it will soon be landing on US soil.

Eager to hear your impressions on the sport suspension.

 

Me Too!

This weekend I've two days of Evo School, and next weekend the last hurrah (NER Regional points event in H Street) with the tweaked R56 Justa (Koni Yellow and Rear Bar). Then the following week I move the saddle from the R56 to the F56 and jump into the stirrups.

So in theory I should be able to notice the differences fairly clearly.

In particular because before I even take that F56 home it will be wearing equivalent wheels/tires - so at least that variable is controlled.

Fingers crossed - I took the loaner for a quick (but fairly gentle) dance in my test area and came away with "it's still a Mini" as the result, but that car did NOT have Sport Suspension so I was not intending to really compare apples to apples.

Cheers,

Charlie

Ps: Jesus do I use enough parenthesis? (perhaps)

 

Since you have tried the F56 without the standard suspension, I'm looking forward to seeing how you compare the sport suspension. I opted for the standard, myself, since I'd like to custom-tailor individual suspension items to my liking. Now if only the aftermarket would catch up!

 

And Gollum is now on dry ground - which makes next week interesting. I am commuting past the NJ docks at o'dark thirty Monday, returning Friday. It is I suppose possible that the current Gollum may meet the new one on the northbound leg back up to Mass. I'll keep an eye out for transporters.

Cheers,

Charlie

 

times fast approaching! you'll barely have time to break it in before nats! ...but im confident that you will. very eager to see how the car does in GS here