6 speed gearset for ST165/185/205

[Wolf_Tm250]

agree with terryo.

like on my mini, i had a cooper's' gear set which made the 1st nice and long, second was almost skipable but not quite. made it a much more fun car to drive etc.(only 4cogbox tho)

so yeh everyone agrees on the long 1st, 6th for me i wouldnt care if it's the same as the current 5th(mr2sw20) or only minimally taller and then space all the gears evenly in between.

Yes, agree with both of you... and in fact the 6th gear ratio I used in the project is only a bit taller than stock.

This is the latest revision of the project... bit shorter 2nd gear, bit longer 5th gear:

[Wolf_Tm250]

Just saw this thread posted over on MR2oc.com.

I'm not sure about other Toyota cars, but the frame rail on our MKII MR2's (yaya.. whatever you call it) is pretty tight by the cover. How much higher do you think this will get? Let me put it this way, I had to replace my 5th shift fork not too long ago ... required dropping the transmission down from the car until the crank pulley was sitting on the other rail.

I'd give you exact clearances, but I'm too cozy inside to jack it up in Winter

Yes please, thanks!

I don't know how much it'll be higher, but I'm going to Bacci in Florence tomorrow morning with my g'box... so we will know soon the MINIMUM higher needed

[Wolf_Tm250]

From the looks of the gear layout, it goes:
1st ... reverse ... 2nd ... 3rd ... 4th ... 5th

I can't quite understand the synchro layout, but it looks like 5th has its own syncho on the end of the shaft.

Exactly!
This is what we will try to do, so the 5th gear cover would be higher the minimum we can !

[Wolf_Tm250]

Why don't you just adapt up the Saab F40 6-speed? It comes in two flavours, FWD and AWD.
It is good for over 400nm of torque.

Unfortunately 400nm is way too low... personally I'm around 600nm now, but a slightly modded 3SGTE arrives too easily at that torque number...

[Bill Strong]

but that is four cylinder torque right? rather peaky, not the same as a V6 or V8 flat torque curve. The transaxle is not under that amount of power for very long.

But it was just an idea.

The majority of the guys in the states have no clue what a custom gear set would cost them, and I would suspect that only a few would even consider it once the cost is made public.

[Wolf_Tm250]

but that is four cylinder torque right? rather peaky, not the same as a V6 or V8 flat torque curve. The transaxle is not under that amount of power for very long.

This is not important, even if a 4 cylinder turbo engine has quite a wide torque... if a gearbox is rated for a torque limit, it doesn't care how the torque curve look like...


We will know soon the price... a C-one close ratio gearset costs around 2000$ if I remeber correctly:
this is another story, we are talking about a 6 speed conversion, so it should be more expensive.... but the fact is a Building for a Group Buy, will make it way cheaper for the factory AND for us... I hope...

[Bill Strong]

Cool. I'll watch this thread and keep the yanks updated since I sorta run the MR2OC

I am building a Rev2/3 hybrid ST165 GT4 so I would be interested as well.

[oldcorollas]

Unfortunately 400nm is way too low... personally I'm around 600nm now, but a slightly modded 3SGTE arrives too easily at that torque number...

thats a pretty healthy 3SGTE! with 2.2BAR or2.5BAR boost? has to be at least 2 BAR ....
doesn't 30psi make it a bit peaky?

[web]

thats a pretty healthy 3SGTE! with 2.2BAR or2.5BAR boost? has to be at least 2 BAR ....
doesn't 30psi make it a bit peaky?

Why do you think he wants closer ratios in the first place?

[oldcorollas]

Why do you think he wants closer ratios in the first place?

i'm wondering what fuel....

[Wolf_Tm250]

Why do you think he wants closer ratios in the first place?

Ah ah, wrong!
It'd be too easy to build an "high hp for 10 seconds", or an high torque@high rpm engine!
When i built it i looked only at increasing the area under the curve, keeping the max torque under 5000 rpm... so i don't absolutely have a peaky torque curve!
In fact you are right... personally i just need it only for the longer 1st gear i use in our mountains' roads hairpin turns!

OC, 30 psi with 101 ron pump gas...

[oldcorollas]

OC, 30 psi with 101 ron pump gas...

...
that helps (btw, vid sounds good too )
must be a very fat curve!

[Wolf_Tm250]

...
that helps (btw, vid sounds good too )

Thanks Mate!

As I told you, this morning I went to Bacci's factory to take them my g'box and to talk about the project:
I'll have a reply in a week.

In the meanwhile, some pics of the factory, even if, for unknown reasons I deleted a photo of a fantastic full sequential 6spd box for a Delta Integrale Grp.A they were building... :

[terryo]

we have custom gear makers here in australia that we deal 2 of them via my work. one of them makes the 5 speed dog box for the WRC Corollas (based on GT4 cases with active centre diff). I have had that company make me custom gears & LSD centres before. The MINIMUM cost is usually A$1000 per pair of custom gears (like to moduify 5th on a stock box), and a full 5 speed dog engagment set with modiifed shafts, is typically A$7000-A$8000.
if this deal in italy falls over, I'll happily investigate here as I have the contacts and they already have patterns and intimate knowledge of this box.

[wagonist]

we have custom gear makers here in australia that we deal 2 of them via my work. one of them makes the 5 speed dog box for the WRC Corollas (based on GT4 cases with active centre diff). I have had that company make me custom gears & LSD centres before. The MINIMUM cost is usually A$1000 per pair of custom gears (like to moduify 5th on a stock box), and a full 5 speed dog engagment set with modiifed shafts, is typically A$7000-A$8000.
if this deal in italy falls over, I'll happily investigate here as I have the contacts and they already have patterns and intimate knowledge of this box.

I actually may be interested in that.
Since this thread has started, I've been noting at what speeds/revs I been using my box at normally. And crap its waaaaaay too low.
1st-2nd: 25km/h
2nd-3rd: 40km/h
3rd-4th: 55km/h
4th-5th: 70km/h
These are changing so that the higher gear comes in at 2000rpm, which on my engine it will pull quite happily to more than keep up with traffic.
The Vauxhall Cavalier NA 2.0L SOHC (Opel Vectra, or later model JE Camira for the Oz people's) I had when I was in Europe 3 years ago, I could only change into 4th at 70km/h, 5th at 95km/h to get 2000rpm in the upper gear.
It still had enough pull to drive well enough, but then averaged 7.5L/100km fuel economy while averaging 140km/h. Even overtook a Vtec Civic on the Nurburgring which the guy was well annoyed about when he found out the car had cost me €50!

I don't know if the GT4 guys have similar gearing to mine. Can anyone give me some feedback?
Maybe some of you guys have a peaky turbo which means your torque band starts higher in the rev range than mine, but personally I'd just be happier with a taller final drive so I can get fuel economy & be able to "stretch" each gear's use.

Off course, all of this may change after I get "decent" mountain road run in the Adelaide Hills on the weekend.