best trackday 020 box and ratios

Hi, Im hoping to use my mk1 golf to do some of the track day tour next year. ive read all over the place to find out more info about optimised gear ratios for track, as this seems to be everyones first advice.
I had my 9A box rebuilt a few thousand miles ago so it should be in good nick but its still got the original 3.67 final drive in it. Would a 4.2 final drive be good in this particular box or would it take the ratios too low then?

Ive also got a 1.6 box with 3.89 final drive so possibility of using the FD out of this? Or possibly the whole thing, although it wouldnt be a freshly rebuilt box it has about 110 thousand on it.

Whats your opinions?

Cheers guys

 

You may find that early 1.6 box with 3.89 FD will only take 90mm inner cvs.

I would think a 3.94 FD with GTI gear set is a good happy medium to live with. The 4.25 FD is really very low and effectively makes a 4 speed box as 1st is virtually unusable as it is so low.

What tyre size out of interest?

 

well im only running 90mm driveshafts any way, im hoping to upgrade to 100mm but am still trying to figure out from the hundreds of posts what it actually is i need to do the upgrade.

tyres will be 195/50 R15, i do use it as a weekend car too so wouldnt want to go too low so as i can still cruise in 5th.

 

Find some rocco 100mm drive shafts. Job done.

You will need to use a gearbox casing that will take the 100mm inners though.

Tyre size is fine at that. It was only if you had stupid big or stupid wee tyres it would have had more of an effect on overall gearing.

You can always fit a 0.75 5th as an overdrive to raise gearing for cruising.

 

What about the engine? Tuned or not, max rpm's?

Last month I ran a slighly tuned (cam = 125HP) 1600 gti on Spa, it was fitted with an FP (4.17 Oettinger)
and was still too long.

A 4.25 gives you 168 kph (105 mph) at 6200 rpm, which is a lot too much on most of the tracks, I'd prefer a 4.47 (100mph @ 6200).

 

What tyres size are you running Bill?
4.25 with 0.91 5th and 185/60 14 or 195/50 15 (yoko AO32 and AO48) gives 111mph at 6500 or 120mph at 7000.

The trouble with anything lower than a 4.25 when using std GTI gear set with 3.45 1st means you can take off in second. I could launch in 2nd with my old 4.25 and 2.12 2nd.

The other thing about having such a short final drive is you can sometimes run out of revs on a short straight meaning a momentary up change and down change prior to the corner which can upset handling. It becomes very circuit specific.
I sold my 5 speed 4.25 for this reason. 2nd was too low for the hairpin, 3rd too low for chicane, and then I only used half of 5th on the straights. Not ideal.
My new 4 speed with selected ratios is perfect everywhere on the circuit I visit.

I believe the OP is using an ABF engine in a mk1 so plenty go about it.

 

Tyres were 195/50-15 (Toyo R1R).

To be long enough on the 2nd gear, you can use the 1.94 one from AUG and lot of other boxes.

If you want to visit different tracks, your gbox must be a compromise.

You build yours for a specific circuit.

 

Yes, for a specific Scottish circuit.....Knockhill.....the only one.
My box will probably be useless anywhere else.

I went one better than 1.94, I got 1.75.

I stripped 5 boxes to get the ratios I wanted. I still do not know how or why as it was only a 4 speeder I was building.
There were and still are boxes lying everywhere here. If you or anyone are after any specific ratios let me know. I will probably have them here. Have a 4.17 4 speed FD here too, if that is what you were using and need a spare.

 

where did you found that 1.75 2nd from danster?

 

It is pretty rare.
The other problem is that 1st and 2nd gears are fixed on the input shaft. This means you have to try and source either a 4 or 5 speed donor box, depending on which you want, to get the shaft and matching gears for the output shaft from.

I believe some later 020 5 speed boxes went back to 1.75 2nd gears though so a little digging may throw up a code or two.

 

hm..if you find something let me know

 

For a track mk1 being used on a variety of circuits- the 3.9fd with 2Y ratios would work very well IMO

 

I'm using a 4.25 on 16v ratios on 195-50-15 with my ABF and find it just right for track work. It almost pulls all of 5th at Combe and does top out at Bedford GT. However, it is far from ideal on the road and makes motorway cruising interesting . It's also too short for the Ring. Oh, and 1st is useless but you never use it at tracks anyway . I had the 3.89 before this and was almost just as good as the 4.25 in the lower gears, it's only the higher gears that make more use of the 4.25.

Gurds

 

I run 4k innards in a CHB case fitted with a WaveTrac diff.

That gives me the close ratio set with a 3.94 R&P.

I had to use the CHB case as the wavetrac required substantial clearancing of the 4k box if it were to fit.

For the fastest track I run at (Phillip Island) I'm just hitting redline in 5th towards the end of the straight.

 

the engine is a failry highly tuned 8v, with a max revs of about 6000ish rpm as it doesnt have forged internals.

The 9A box is pretty much the same ratios as the 2Y apart from fifth being 0.91 in the 2Y and 0.89 in the 9A. i still need to keep it useable on the road so im thinking maybe try the FD out of the 1.6 box in my rebuilt 9A?

Would the 1.6 box internals fit into a newer 020 casing?

 

The 3.89 FD crownwheel and output shaft could be fitted in your 9A box.
In fact you could install the whole diff carrier assembly from the 3.89 box to save splitting the crownwheel rivets. But a crownwheel bolt kit would be a good upgrade as would an lsd. The diff carrier assembly will need shimmed, as will the output shaft bearings in the 9A casing.

A couple of things that may be an issue is if the 3.89 diff output stubs had the spring loaded cone for the output flanges. And also if the 3.89 output shaft has extra length to it, as some of the output shafts ran in and extra bearing in the 5th gear outer casing.

 

Definately fit the diff bolt kit! I had 4x gearboxes apart this weekend and 1 had popped its rivets and the other 3 had the rivets starting to walk

Gurds

 

A diff bolt kit will deffinately go in there when it gets stripped down, im just a bit reluctant to strip it down as it was only rebuilt 6 months ago, in hindsight i should have thought of this then but i was never intending on using it for track days when i had the box built.

An lsd would be lovely but at around 750 for an LSD and crown wheel bolt kit it gets a bit pricey!
Would stripping down the box and replacing the diff rivets with bolts and changing the FD be a job for an experienced amateur mechanic? i just dont really want to pay for the box to be rebuilt again just to change the FD and bolts. Ive looked on brokes site and it seems pretty involved!

 

What about the wave track diff? is it as smooth as a Torsen, do you feel it in the steering wheel? In the past I ran discs diffs, and (don't remember the english name of french "galets" like "rolling stones"!!) which ask a lot of effort, as the Torsen behaves like a normal non locking diff.

To definitely answear te title of this post, the best 020 is the motorsport kit for 8v I found on ebay for 500€, 1st 2.5, 5th, 1.03 cwp 4.25 giving 193 kph @ 8000 rpm at Spa with the Oettinger (3"01" on 195/50-15 Toyo's).

 

You lucky man! That is cheap.

Gurds