6 speed gearset for ST165/185/205

[jonathan yee]

any update?

would be wicked if it could be made as a sequential.....but that would make the price...............?????????(crazy i know)

[Fodder]

Bump - any more info here?

[Wolf_Tm250]

Hi Mates,
called yesterday... they are still working on it...

[ToDa30/4]

Sorry big zop, I appreciate your help, but I still think you're not understanding the point...

we have NOT to choose correct ratios for a GIVEN car, with a GIVEN power curve, racing in a GIVEN track or in a GIVEN drag race...
in this case I would be with you, searching and changing ratios according to what is gonna give us the best performance.

BUT we are in a TOTALLY different scenario:
many DIFFERENT cars, with DIFFERENT power curves, in DIFFERENT tracks or situations!
So completely unuseful to try to calculate something, because you have NO fixed/given data.
What we know, and this is the only thing common in all our cars, is that the 1st gear is too short.
And what we also know is that shorter gears can let us choose the correct gear almost in EVERY situation: you can choose the shorter or the next longer one because you would have ONLY 1700/1400 rpm gap between them.


For example, look at the ST205 graph:


With the stock ST205 box, if you have to run a 135 kmh turn, in 3rd gear you'll be with engine at 6300,almost at the end of the power curve... while in 4th gear you'll be only at 4500 rpm... too long gear !



Look now at the ipothetical 6 speed mid#2 in the same situations:


In 135 kmh turns you can choose to be in 4th gear at 5800 rpm OR EVEN in 5th gear at 4700 rpm.

There is nothing more to say... a shorter gapped gearset will always let you have the engine at a good rpm.

Graham Bell in his book says:
"A car with a set of nicely spaced cogs is always much more enjoyable to drive.
Ideally, in a road car, we want 5 close ratio gears for performance, plus a big overdrive top gear for effortless cruising.
The Subaru Liberty, like the Impreza WRX, has an unacceptably large gap, over 29%, in the vital 3rd to 4th step.
The other, though, are all a little under 24%.
This is what we want, anything wider 25% is too big"

alot of blaa blaa but reading those charts i must have had the 185 Gt4 up around the 270kmh a few times ...sweet

[ToDa30/4]

i have built numerous special close and wide ratio boxes for race & rally Gt4's. I have all the ratio data.
there are 2 basic choices for a 6 speed, narrow the 1-4 gears and fit 5 in there, or pack out the 5th section and fit 2 in there. the latter would be the easiest choice, but the selector mechanism would be much more difficult.
narrowing the gears inside the cases is what was done in the RAV4 V6 boxes, and they are already giving problems. with custom gear making, special steels etc, that might be OK however.
whatever you do, you have got to get 1st gear correct for the application. in most cases, we chase about 3.0:1. much lower than this (like 3.4 or so), and 1st gear becomes useless in a serious performance engines, as all you get is wheelspin, and not very far before you have to change gear.
personally, for circuit work, I like to have as tall a 1st gear as I can have, cause that gets you further before the all important change to 2nd. keep the 1-2 gap small.
in a road car, that is not quite so important, and you often need a low 1st gear for the occassional hill start etc.
i doubt a single gear set would suit all possible users.
My circuit race car has a 7 speed gearbox (4 conventional plus 3 overdrive). for each track, we know what ratios are needed and we select which overdrives to use so we can get fast shifts between the conventional gear and the overdrive (which is switched electrically and faster than a conventional change), for example, on long flowing tracks like Phillip Island, apart from the start, you really only need 3 widely spaced gears (2, 3, 4) , but on short winding/tight tracks like Warwick, you need 4 gears, but packed much closer together , 2, 2 o/d, 3, 3 o/d. In this case, the overdrive is a 18% change between the base ratios.

terryo i want a 6 speed for a SST215 wagon with a ST205 box in it i ass,u,me ....could you PM me a quote dude.. cheers dave

[ToDa30/4]

ST205 maybe, but the ST185 comes in at close to 1400kg, and my Caldina weighs 1470kg empty. So add 5 people (at a squeeze), their luggage, plus anything extra on the factory roofracks, and you can safely say that the 1600kg is blown out of the water.
And then there's the towbar I want to fit so I can tow my race car around (add another 1200kg)

St185R GT4 came in at 1620 kgs. with full strip out & 6 point cage in with full tank

[Cuts]

I weighed the 205 the other day, with about 1/4 of a tank of juice (full interior, except no boot plastics) it came in at 1370kgs. As the wheels weigh over 20kgs without tyres I should get close to under 1300 with some decent wheels and a bit more of a diet.

[JustenGT8]

What weigh bridge Cuts? That just sounds way too light?

[Cuts]

One at a local scrap yard, I asked the same question because I was disappointed in the weight.

[JustenGT8]

LOL a scrap metal weigh-bridge underweigh? ....never

[Cuts]

I'm hoping it was overweight. I've done a bit of lightening on it.

[JustenGT8]

Mine was 1460kg with 1/2 tank and your spec 205 should be 1440kg 'laden'. With the heavy wheels, dropping to 1370kg would be a huge task? Mine is around 1380kg now and it's pretty well gutted?

[Cuts]

You make a compelling argument sir. I shall endeavor to put it on another bridge over the coming weeks and see whats up.

[JustenGT8]

There's a reason they aren't rattly buckets like old WRXs the chassis are solid. If you do get yours under 1400kg i'll have to try harder

[Cuts]

You're on. I'll put my stock wheels back on, hehe.