The Ultimate Be Trackday Gearbox

[petert 553]

We had a great day at the track yesterday but my son suggested why not build a 6 speed? Two of the three tracks we run on are short & twisty and the other is a straight hp track with just a few corners. The idea of using 3-4-5 for the short tracks, then slipping into 6 when necessary for the long track does sound appealing. The current box is 205 GTi with a 4.75 cwp. The GTi6 box with either a 4.43 or 4.75 cwp from Bacci Romano would be ideal.

 

Here's our speeds in km/h @ 7600 with the 205 gear set and 4.75 cwp:

58

91

124

158

195

Here's the GTi6 gear set with a 4.43 cwp:

62

97

128

157

190

229

Here's the GTi6 gear set with a 4.75 cwp:

58

90

120

147

178

213

 

 

Other than steering lock issues, which isn't an problem for a track car, does anyone have any words of wisdom?

Edited October 22, 2012 by petert

[mollisk 2 1 Cars]

PAM Sport in France also do various motorsport CWP's for BE3/6 gearboxes ( up to a 5.6:1 from memory ). These are SMAN manufactured

I use a 5 speed gearbox with 1/2 from a 1.9 gti and 3/4/5 from the 6 speed with a 4.9:1 cwp from a partner van and gripper diff set to approx 40 lb/ft.

I did try a BE 3/6 gearbox with a 4.9:1 cwp in a 1.6 gti rally car, but steering lock was a problem and 6th gear was never used when competing, only on road sections.

I find that the modified 5 speed gives the best results when building a gearbox to a budget.

Most of the French F2000 rally cars seem to use the SMAN 6 speed dog box which uses a modified 5 speed casing ( again see PAM sport site ), but that is rather expensive.

 

Mollisk

[EdCherry 34 1 Cars]

2 Gearboxs. One short track, one long track. No compromise.

[Cameron 16]

A bit excessive for track days Ed!

[EdCherry 34 1 Cars]

Meh, gives you something to do inbetween trackdays, not like its a long job!

[mollisk 2 1 Cars]

Or you could just change the fifth gear ratio to one from a 1.9 gti 'box if you require a higher top speed. The cup gearboxes for 106's came with 2 fifth gear ratios for such eventualities.

 

Mollisk

[petert 553]

Changing just 5th gear kills the percentage change from 4th to 5th however. I should point out it's for competitive super sprints rather than just track days. EdCherry is probably right - have two.