F55/F56 Gollum III - well mebbe a teeny bit of stinkin' powah?
#26
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
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
#27
#29
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!
#31
#32
and look for fragments of brass in the leavings??
but of course i agree...
#33
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.
Does that have any validity today? Or is the longer stroke a willing compromise for greater torque?
Yeah, I'm getting old.
#34
#35
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.
Does that have any validity today? Or is the longer stroke a willing compromise for greater torque?
Yeah, I'm getting old.
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
#36
Sneakers for the eagerly anticipated
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
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
#37
OVERDRIVE
iTrader: (1)
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
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
#38
#39
#40
#41
#43
#44
#45
#47
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)
#48
#49
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
Cheers,
Charlie
#50
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
Cheers,
Charlie