[Land-speed] Chassis Dyno Operations

[FFR554 at aol.com]

My experience is that the normal loss between an engine Dyno pull and a  
chassis dyno pull is  5 - 10% using a standard transmission and  
non-quickchange rear end in high gear .  The loss increases in lower  transmission gears. 
 With a quickchange the loss may be as high as 20%,  depending on ring & 
pinnion ratio and final drive ratio.  The fewer  gears, the better.  
Quickchange's give flexibility, but rob  horsepower.
 
Bruce
 
 
From: drmayf <drmayf at mayfco.com>
Subject: [Land-speed]  Chassis Dyno Operations
To: "LSR" <land-speed at autox.team.net>
Date:  Saturday, June 12, 2010, 7:46 AM


More fun dumb questions from  me.  Why do we use high gear during a chassis
dyno pull?  The dyno  does not know what gear the car is in, does it?  Is 
there
a general  limit on the acceleration rate of the rollers?  If high gear 
(1:1 in
the  gear box) is better than a lower gear, then would overdrive be better  
that
the 1:1 gear?  Is there some final drive ratio that is best? Or is  top 
speed
the consideration?   And why does shifting during the  pull matter?   Are 
there
other considerations in how the pull is  accomplished? Isn't the desire to 
get
tuning data for the enitre rpm range?  Or should it be for reliability at 
peak
rpm?

anyhoo, just fun stuff  before breakfast...

comments? thoughts?  flames?

mayf
_______________________________________________
Land-speed at autox.team.net
Donate:  http://www.team.net/donate.html
Archive:  http://www.team.net/archive
Forums:  http://www.team.net/forums
Unsubscribe/Manage:
http://autox.team.net/mailman/options/land-speed/v4gmr@yahoo.com
_______________________________________________
Land-speed at autox.team.net
Donate:  http://www.team.net/donate.html
Archive:  http://www.team.net/archive
Forums:  http://www.team.net/forums
Unsubscribe/Manage:  
http://autox.team.net/mailman/options/land-speed/ffr554@aol.com