Torque BS Filter ``

[DICK BREWSTER]

--IMA.Boundary.679008658
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Description: cc:Mail note part

>On Fri, 21 Feb 1997 07:50:36 -0600, DICK BREWSTER wrote:

>>Stuart, a very good smell test to use on torque claims for 
>>naturally aspirated four stroke gas engines the 1 to 1.1 ft-lb 
>>per cubic inch test.

>Well, perhaps if you think a bit about the fact that 8.5 l is around 
>518 cu.in, then 500+ ft-lb of torque would be quite doable?

Stuart, I wasn't aware that engine was 518 cu in.  At 1.03 ft-lb 
/ cu in it falls right in the 1 to 1.1 range.  


>>Very few streetable engines get much over 1 ft-lb per cubic 
>>torque.  Some of the better engines get up to about 1.1, but 
>>that's about it for an accurate dyno test under real 
>>conditions.

>and then if we figure in the fact that I never said this was in a streetable 
>car, as infact the application is an aircraft engine, running at more or 
>less a constant 3000RPM, would you not say that this is quite an easy 
>target?

Yup, and they seem have hit someplace near the bottom edge of the 
target.

>>The reason is it's hard to get much over 100% volumetric 
>>efficiency and the effective compression ratio is pretty much 
>>limited by pump gas.

>and who even mentioned pump gas?

Doesn't make much difference if you are talking avgas.

>and remember, allow for the fact that the combustion chamber on a stock jag V12
>engine is capable of running 12.5:1 compression with a mechanical distributor 
>on 91 octane fuel (just)..

And the point is???

>BTW. this same setup is reputadly good to over 800 ft-lb 
>supercharged (as it is in full use in the airframe..)

and the connection to 1.0 to 1.1 ft-lb / cu inch for a naturally 
aspirated engine is????


>>>I believe people have got over that from stroked V12 jaguar 
>>>engines, supercharged.
>>>around 500lb-ft without the supercharging. running around 8.5l 
>>>of capacity, and on avgas.
>>>however, these have a VERY good head design (for the time), 
>>>which allows this, a
>>>standard jag. XJ12 is 12.5:1 compression on 5.3l, but they have 
>>>a VERY advanced
>>>distributor (and later computer controled ignition) to control 
>>>detonation problems.
>>>
>>>not exactly a bus but...

>so would you like to repeat your claim of me presenting BS? 
>or am I really missing something?

Where did I claim you presented BS?  Or am I really missing something.

--IMA.Boundary.679008658--