[BMWCSRegistry] Weber 38/38 linkage & top end performance

[paul.briggs at att.net]

Thanks for the info from everyone.

I looked at my linkages this morning, and the Webers, the throttle (when pedal is on the floor) only opens  about halfway - call it 45 degrees.   It should open to 90 degrees (fully vertical) right?   So it appears mine have this mechanical limitation.   Again, they are Weber 38/38's installed via a kit from JAM Engineering, and run great (smooth idle, lots of torque), but have no top end.

Pictures at: 
http://good-times.webshots.com/album/559205002qOktdv

Carlos - let me know if you need a different view...kind of hard to photograph in there.

- Paul

'74 3.0CS
'73 2002tii
'95 540i/6spd - FOR SALE! 


From:"Bill Proud" <bmwbits at bellsouth.net>  [ Save Address ] 
To:"E9coupes BMW" <bmwcsregistry at idb.ded.forest.net>
Subject:[BMWCSRegistry] Webers 
Date:Sat, 26 May 2007 18:15:28 -0500


A little side-note ....Weber 32/36 carbs have a PROGRESSIVE cam and pin linkage such that the secondaries dont start to open until the primaries are nearly fully open , so you can sometimes feel the point at which this happens .
Weber 38/38 are mechanically SYNCHRONOUS opening ......both sides are driven open by a pair of external little gear teeth ...so there should be NO sudden step in pedal-feel just a progressive tightening as you push harder against the spring .If you arent getting full power to redline with 38/38 s then I will bet that your linkage is restricting their opening at the top end . DONT overlook the fact that your motor torques around the motor mounts and that can affect the opening linkage . A fairly easy check to make is to disconnect the linkage at the carbs , open the carbs manually and verify they are fully open by looking down the holes . Block them open in that position (Stuff rags down em ) . Now check to see if the rest of the linkage will reach them ...........if not , I rest my case ......
Also ....do you have nice thick over-carpets on the drivers side floor ?? Sometimes they restrict linkage motion .
Check the simple stuff first !! 
From:"Bill Proud" <bmwbits at bellsouth.net>  [ Save Address ] 
To:"E9coupes BMW" <bmwcsregistry at idb.ded.forest.net>
Subject:[BMWCSRegistry] Webers 
Date:Sat, 26 May 2007 18:15:28 -0500


A little side-note ....Weber 32/36 carbs have a PROGRESSIVE cam and pin linkage such that the secondaries dont start to open until the primaries are nearly fully open , so you can sometimes feel the point at which this happens .
Weber 38/38 are mechanically SYNCHRONOUS opening ......both sides are driven open by a pair of external little gear teeth ...so there should be NO sudden step in pedal-feel just a progressive tightening as you push harder against the spring .If you arent getting full power to redline with 38/38 s then I will bet that your linkage is restricting their opening at the top end . DONT overlook the fact that your motor torques around the motor mounts and that can affect the opening linkage . A fairly easy check to make is to disconnect the linkage at the carbs , open the carbs manually and verify they are fully open by looking down the holes . Block them open in that position (Stuff rags down em ) . Now check to see if the rest of the linkage will reach them ...........if not , I rest my case ......
Also ....do you have nice thick over-carpets on the drivers side floor ?? Sometimes they restrict linkage motion .
Check the simple stuff first !! 
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