Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: scrw on June 04, 2012, 09:52:26 AM

Title: BHP losses through an auto box
Post by: scrw on June 04, 2012, 09:52:26 AM

I know it is a how long is a piece of string type question but what sort of % losses do you get through an auto box with a lockup torque converter?

 :icon_redface: The wee car got a power run on some rollers yesterday as a base line before I fit the supercharger and from what should be around 133BHP at the flywheel we only saw 84BHP at the wheels, think that is too much of a loss

Title: Re: BHP losses through an auto box
Post by: isle of man on June 04, 2012, 10:23:53 AM

Take your handbag out of it and try again!!!

Title: Re: BHP losses through an auto box
Post by: scrw on June 04, 2012, 10:24:40 AM

sensible answers or  :wave-fingersmiely:

Title: Re: BHP losses through an auto box
Post by: wildwood on June 04, 2012, 10:29:13 AM

Spinning torque converter on older boxes lie a TH400 can sap power

To spin the TH400 takes 30bhp... tis all I know.... newer stuff like 8 speed BMW boxes will be less.....not really a huge amount of help but you get some sort of picture.

Title: Re: BHP losses through an auto box
Post by: scrw on June 04, 2012, 02:18:06 PM

that matches what I thought, the box in the 5 is old school, used in loads of stuff inc IIRC fairway taxis, wasn't expecting it to use more than 30bhp which points to a problem somewhere  :jpshakehead: