6 speed gearset for ST165/185/205

[wagonist]

I actually like the idea of a short first. It helps get the car off the line without placing undue stress on the clutch, etc that a taller gearing would do. And because my redline's only 7000, that only equates to 50km/h in 1st in my car.

2nd gear needs to be shorter though, there's too big a gap & I don't see the point of being able to do 100km/h in it

[JustenGT8]

Yes, track/mountain roads.
The 1st gear is wanted longer because the stock one ( around 60kmh@redline ) is really too short, and the stock 2nd too long, when you have to do a winding road.
Every other gear as a step of 1700 to 1300 rpm, so quite a small step for a turbo, wide range, engine...

Yeah fair enough....i'd still prefer 1st a bee's dick shorter, say halfway between stock and what you have?. I'd make 5th a genuine 1:1 and if you want a cruise gear leave 6th as is...if you have some high speed tracks then shorten 6th to 0.86 so you can use it

BigZop's spreadsheet is interesting so set him loose on it i say

[Roundy]

You can't make FWD gearboxes a genuine 1:1 though, can you?

[JustenGT8]

No idea? why not?

[Roundy]

http://www.billzilla.org/drivetrn.htm

Re-reading it, doesn't seem to say you can't, just that you never see it....

That is all i remember seeing about it, so i am probably wrong.

[Wolf_Tm250]

Mates, given that it would be a sporty mod, and not a drag racing one, the ratios spacing are not according best acceleration or clutch duration, but to resolve issues of the stock spacing in tracks and turny roads use.
The 1st gear is too short and 2nd gear too long in hairpin turns, that's why we would need a longer 1st and a shorter 2nd, like rally cars have.
The other gears are shorter to have smaller gap between each other, for having ALWAYS the correct gear for any turn you will find:
even if i have high torque, and very wide power band, now i'm always finding one gear to be too short and one to be too long.
6th gear is there only for cruising and keep stock top speed.
And this won't be an advantage you can quantify on a software or calculating quarter time!
To have always the right gear in, with the engine always high on hp, is a BIG improvement!

[wagonist]

I'm with Justen on the 1st gear. It does run out real quick.
There is too much a drop off in revs between 1st & 2nd.

In my opinion, the current 5th is not a cruising gear. It may come close to a cruising gear on Japanese roads where the maximum limit is 100km/h, but elsewhere in the world, inlcuding here, there are higher speed limits.

I'm sure in Italy, your motorway speeds are higher.
Here in Australia, our speeds aren't much higher (legal limit usually 110km/h, but we usually add 10km/h), but our distances are much greater.
For example, I am driving from Sydney to Adelaide next week. It is 1100km away. Our country is 4000km across (the size of all of Europe), yet we have a population less than London.
Therefore, if top gear is taller, the European guys can achieve a higher cruising speed for the motorways, and we can get better fuel economy for the long distances.
I have no problems with changing down gears to overtake or climb hills if need be.

Wolf, I'm jealous that you live close to some simply awesome mountain roads.

[jonathan yee]

man i would love to have a 6 speed in my mr2. i hate the ratios.

also my box is in need of a rebuild, but i cant even afford that right now let alone a six speed cog swapper. tho i'd say R&R will take a while an the construction so funds wouldnt be needed right away. definitly be keeping an eye on progress.

i'll juck a link to the aus mr2 site for you. have you put this on mr2oc.com?

[Wolf_Tm250]

man i would love to have a 6 speed in my mr2. i hate the ratios.

also my box is in need of a rebuild, but i cant even afford that right now let alone a six speed cog swapper. tho i'd say R&R will take a while an the construction so funds wouldnt be needed right away. definitly be keeping an eye on progress.

i'll juck a link to the aus mr2 site for you. have you put this on mr2oc.com?

Not yet... and I haven't an account on that forum... please make it !

[Wolf_Tm250]

Might be worth pushing this on the MR2 boards as well since the gearset should be the same for the E153. A lot of dreamers on the MR2oc tend to ask about 6 speeds for the 3SGTE.

Yes, please !

[Wolf_Tm250]

BTW, Wolf, you may want to add the ST215 Caldina to your list Same gearbox, etc, just in a 5 door wagon body. And there was a heck of a lot more made of these than ST205s (pity most are automatic though )

Thanks for the info, I'll add it !

[Wolf_Tm250]

My assumption was that the 5th and 6th gear would sit outside the main box, as the factory 5th gear does, with an extension housing between the box and end cover being utilised.

Exactly, now the 5th is outside, so we'll have to make a deeper 5th gear cover to add the 6th gear...

My primary aim in my thinking was to have a gearset to get the car up and moving quickly and still be competitive in higher gears - yep, I spent a bit of time watching EVO's launch too. As your ratio's depict a 1:1 fifth gear and over driven 6th gear was my desire too - I'm interested, and may know of a few other people here in Australia too, will pass it around.

Perfect, thank you.

[Wolf_Tm250]

For the guys asking for the price...
really don't know how much it will be... but we will know soon:
next monday I'll take them my gearbox, and they'll start working on it.

Other thing I know is that the more we will be in the GB, the cheaper it will be!
So I'm even, indirectly, replying to the guys discussing of the ratios, because you have to understand that:

1. The most important thing is that we have to be many in the GB!
Because if we won't be many, ther will NOT be any GB of any gearset!

2. So the gearset's ratios HAVE to meet the most consent.
Which are the ratios that will get the more consent ?
Who will be happy to buy this gearset ?
Let's think about it...

I don't think a normal road user will buy it, because he will have no need of it.
I think that a better than stock gearset will be bought by sporty mountain drivers, occasionally or not track drivers, rally drivers, drag racers.

So I thought about a better spaced ratios for any of the above situations.

What do fast road/mountain/rally drivers need ?
Longer than stock 1st for hairpin bends
Shorter than stock 2nd for hairpin bends
Less gap between the gears

What do track drivers need ?
Less gap between the gears to have always good power to come out of the turns

What do drag racers need ?
To tell the thruth, really don't know ! I'm not a drag racer... I imagine a good gap between the gears, and maybe more top end ?



Please look at the stock ST205 ratios:


And this is how I think it would be perfect for many/the most mountain/fast road/rally drivers:







But please also consider that just changing the Final Drive to the 3.933, you'll get more gap and top speed:




And even consider that in some slower application ( gravel ? autocross ? ), you could even use the around 4.500 Rav4 Final Drive ( if I understood correctly... ):

[Cuts]

Ide consider it, depending on price etc.

[big_zop]

The only reason i am suggesting to do some computer analysis on the ratios is that you will be able to see the results before you even build the box, or at least be given an indication that you are on the right track.

The aim ratio change for the 5/6 speed boxes that i have presented are from a circuit racing book (cant remember the name - but can get it if you need it). Whie i dont understand the minor differences in the different applications you have chosen (fast road, mountain, circuit, drag), i would think that all have the same objective and that is to accelerate as fast as possible, whether that be to the next corner or not. Now i know that the fast road/mountain ones will have less time for this and having a gear change at the wrong time will really ruin a time but its very hard to estimate ratios for this compared to selecting them for a circuit where everything is in comparison relatively fixed.

One more thing i want to add is that in my analysis, i found that getting the perfect ratios would sometimes lead to faster acceleration, even if you have an extra gear change. When comparing a 5 and 6 speed and if you take that both gearboxes have the same top speed, the only time the 5 speed was ahead was when the 6 speed needed to change which only led to a small percentage of the total run where the 5 speed had the advantage.

Either way you decide to go selecting ratios, it isnt very hard or time comsuming to do some analysis and i would like to help any way i can. Like i said, i can modify the spreadsheed to show anything you want and although right now it is configured to do a 1/4 mile run, i can select any start speed (exit speed from a corner for instance) and for a prescribed distance (entry to next corner) give you the final speed and total time (including time breakdown per gear to see if its lost in the gearchanges).