Re: bore/stroke (was Re: [T3] 74/78 crank?)

[Per Lindgren <lindgre@online.no>]

<x-flowed>One thing is certain, longer stroke equals more torque. On example that 
clearly shows this is for the VW Vanagon. The wasserboxer is basically a 
water cooled type 1/3 unit. There were 2 versions of the watercooled 
engine made, if one sees besides facts like US vs Euro models with 
different FI setups and emmision systems.

The 1983.5-85 US model had a 1.9 liter (94 mm bore x 69 mm stroke). As 
you can see, it had the same stroke as our engines, and a bore quite 
commonly used by the aircooled hi-hp engines. The 1986-1991 models used 
a 2.1 liter version, it still retained the 94 mm bore but got a 76 mm 
stroke. The hp output was only up by 5 hp, but the max torque was upped 
by 10 lbs-ft from 108 to 118 (or 147 Nm vs 160 Nm for those into 
metrics). I do not believe that the FI system accounted for all of the 
increase.

Another example is a diesel engine. These engines utilize a longer bore 
more than a gasoline engine does. They do this on behalf of the maximum 
rpms, but then again diesels tend to not like high rpms anyways. VW's 
1.9 liter TDI has a 95.5 mm bore teamed up with a 79.5 mm piston, for 
more torque than one is capable with a gasoline engine.

PerL
73 Variant L
70 Variant


Greg Merritt wrote:

>     What do the modern-day VW and Honda know that we don't?


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