Home  
Site Partners: SpotterGuides Veloce Books  
Related Sites: Classic Cars Monthly Your Link Here  

Go Back   TenTenths Motorsport Forum > Historic Racing & Motorsport History > Motorsport History

Reply
 
Thread Tools Display Modes
Old 21 Mar 2008, 09:40 (Ref:2157943)   #1
Henrik Pedersen
Racer
 
Join Date: Jan 2002
Denmark
Denmark
Posts: 245
Henrik Pedersen should be qualifying in the top 10 on the grid
Index of Performance/Thermal Efficiency (Merged)

Does anyone know how they calculted the "Index of proformance/Cubic" at Le Mans?
It was, from what I know, a formula that had mileage/cubic, but it changes over the years.

Would entrant to Spa 6-hours, that have an interest in a "Index of proformance" Trophy, come forward in this tread.
Henrik Pedersen is offline  
Quote
Old 21 Mar 2008, 19:11 (Ref:2158405)   #2
Henrik Pedersen
Racer
 
Join Date: Jan 2002
Denmark
Denmark
Posts: 245
Henrik Pedersen should be qualifying in the top 10 on the grid
Index of Performance/Thermal Efficiency

Can anybody tell me what the calculations and formula behind the "Index of proformance" and "Index of thermal efficiency" was at Le Mans?
Henrik Pedersen is offline  
Quote
Old 24 Mar 2008, 08:29 (Ref:2160106)   #3
John Turner
Race Official
Veteran
 
John Turner's Avatar
 
Join Date: Mar 2003
United Kingdom
Pontesbury, Shropshire
Posts: 13,226
John Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of FameJohn Turner will be entering the Motorsport Hall of Fame
These were two entirely different awards; that for the Index of Performance a relatively simple calculation; that for Index of Thermal Efficiency a far more complicated affair that surely only the French could have come up with. Much perusing has found brief explanatory references in Hodges 1963 book, and Clausinger's from 1982.

The Index of Performance was an annual award that grew out of the Biennial Cup (itself a replacement for the once only awarded Triennial Cup - 1923-25). The IoP was a simple calculation where the distance (D) actually covered by the car was divided by the distance set (presumably!) by the ACO based on engine capacity (D1). Of course, the distance set, I guess was changed every year as performance in cars in general increased.

For the Index of Thermal Efficiency, I am going to have to quote verbatim from Hodges, since it is beyond my ability to put into easier form! Initially, it 'equated speed, weight and fuel consumption as follows

P+200 + V + (V -100) squared + (V-140) cubed
200 16 500 12000

All the above divided by E, where:-

P (Poids) = weight in kilograms with oil, water and spares but no fuel
V = the race average of the car in kph
E = energy in litres of fuel per 100km.

Got that! The formula was then modified in 1961, and then allegedly simplified 1962 and expressed as

Em
Er

where Er = consumption in litres per 100km, and

Em = 1.5 + (P + 1) V cubed
4 x 105

Where P = weight (now including fuel, but not tools) and
V = average speed.

As you can see the format of posting here does not allow me to place the 'divided by' figures directly under the 'divided by' lines (at least, I don't know how to do it) but I'm not sure it would make it much easier to understand, if I could!

Last edited by John Turner; 24 Mar 2008 at 08:40.
John Turner is offline  
Quote
Old 24 Mar 2008, 13:03 (Ref:2160269)   #4
Henrik Pedersen
Racer
 
Join Date: Jan 2002
Denmark
Denmark
Posts: 245
Henrik Pedersen should be qualifying in the top 10 on the grid
Hi John

Thank you for a very specific answer.
I will try to find the books you refer to, and work my way back.

Regards
Henrik
Henrik Pedersen is offline  
Quote
Old 24 Mar 2008, 18:59 (Ref:2160467)   #5
D-Type
Veteran
 
Join Date: Mar 2003
United Kingdom
Coulsdon, Surrey
Posts: 585
D-Type should be qualifying in the top 10 on the grid
You could try writing to the ACO and asking them directly
D-Type is offline  
__________________
Duncan Rollo

The more you learn, the more you realise how little you know.
Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
thermal cameras woodyracing Racing Technology 7 7 Feb 2005 02:55
Engine Efficiency dedieux Racing Technology 14 11 Apr 2002 08:15


All times are GMT. The time now is 04:22.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Original Website Copyright © 1998-2003 Craig Antil. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2004-2021 Royalridge Computing. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2021-2022 Grant MacDonald. All Rights Reserved.