gear box ratios

[mk3 gti]

hello, as i has blown a hole in my gear box i pulled it out today and pulled it apart to see if i blew the spider gears or a rivet on the crown wheel. as i stripped the box i inspected the rest of the bearings, gears and syncros. and it all looked good as for the diff i blew the spider gears. so i am going to replace with a lsd. and for the hole in the box tig welder.

as i don't drive the car often drive the car on the road more track use i've decided to play around with my ratios. these are the stock figures

these figures are worked out from ccm stock gear box with no resistance and a slightly modded aaa motor worked out off my own car.on 215/45/16 wheels at 7000rpm

1st (3.300) 70.97kmph
2nd (1.944) 120.2kmph
3rd (1.308 ) 178.6kmph
4th (1.034) 225.9kmph
5th (0.83) 281.4 kmph
f/d (3.389).

as most of us don't use the true speed power of are cars i am playing with my ratios to get better acceleration as we don't use top speed on the track or the road.

these are if i change the finale drive from 3.3 to 3.8


1st (3.300) 63.15kmph
2nd (1.944) 107.5kmph
3rd (1.308 ) 159.3kmph
4th (1.034) 201kmph
5th (0.83) 251kmph
f/d (3.8 ).

these are figures if i changed 3rd n 5th gears to transporter gears and 3.8 ratio

1st (3.300) 63.1kmph
2nd (1.944) 106.4kmph
3rd (1.346) 154.8kmph
4th (1.034) 201.4kmph
5th (0.837) 248.5kmph
f/d (3.8 ).
has any one had an experience with ratios and no a good combination.

also replacing the fly wheel with a light weight one, heavy duty clutch and timing chains while the box is out.

[Ben J]

I've wanted to go to a 3.94 R&P and a longer tdi 5th gear (to keep revs low when cruising on highway etc) as the gears really are quite long, like around town you're not getting any fun in second until about 70km/h, where it would be much nicer for it to kick in that bit earlier, through roundabouts etc.

That last set up you posted looks like it would be a bit of fun!

[mk3 gti]

Car collecting dust till I rebuild the box

[mk3 gti]

The 5c peace hole in my bell housing

[MattyT]

haha, nice work

[Peter Jones]

I run a CHB 020 box with 4K internals and a 3.94 R&P over a WaveTrac diff.

Ratios are

3.45, 2.12, 1.44, 1.13, 0.89 with a FDR of 3.94

In other words a close ratio stack in a late model box with an LSD.

Good combo on the track, nice and punchy out of the corners and just the right FDR to be hitting red line at the end of the straight in 5th.

I change at 6500 rpm (or above) to keep the revs above 5000.

Tyres are 185/60/14 so a circumference of about 1814mm

[mk3 gti]

Track wheels