Mike555

We know the parset of Lateral isn't strong enough to handle +450 bhp. So a lot of people are installing the STI 6 speed. But has this already prove how much this can handle?
I do not want to pay over 3000 pound for a gearbox that brakes in pieces when i am dragging or just having fun at the traffic lights.

Regards Mike

john banks

I'll break it for you and then tell you

I gather that Jun did 4 lauches in a powerful car ?hyperlemon and the 5MT broke. They went on to do 100 with the 6MT and it did not. This of course proves nothing but is interesting.

The 6MT is a complete new design which is a relatively rare event for a manufacturer. The vintage of the 5MT is long apparently.

I also heard that the 6MT received a gearbox design award, which anyone that knows the 5MT will realise makes it on a different planet.

It is incredibly heavy, large and rigid - even to the point of all the ribs cast(?) into the casing which is meaty.

Installing a 5 speed in your garage might rip a nipple off when you are wrestling with it, this thing will take limbs off.

At the end of the day it is a good guess based on few failure stories apart from US newbie stick drivers over-revving it. And it has been out what 2 years now and used on some modded cars?

Given a failure rate of PAR kits supplied in Europe at least in the teens in percentage terms, I think we would hear about more 6MT failures by now, but you never know.

[Edited by john banks - 1/9/2004 11:31:21 PM]

Mike555

In the USA the stock STI 2.5l has already got 420nm. This is great torque and the Enginers of STI has to make a gearbox to handle this power. But how much marges has they calculated in it. Is it on his max or we can add some more nm on it.
What John said the design has been improved, no doubt about it, after many gearbox failures. Hope those people have learned about it.
Still waiting for the first topic about failure of the 6 speed. Or this topic will never come

Cheers Mike

Mike555

By the way, who is driving with a 6-speed?
John Bank
........

Adam M

shame that 6 speed ratios are **** poor if you have a torque monster.

Even the UK ones are far too low.

I wouldn't mind something like skyline gearing.

Mike555

The skyline gearbox is strong enough for 550bhp. A pitty that is og compatible with our car

[Edited by Mike555 - 1/10/2004 9:45:05 AM]

EMS

Mike,

You could use it as a 3-gear box! Start in 2nd, then 4th and then 6th........

Mark.

T-uk

agree with adam about the gearing of the 6speed.

I think jb will find the first 4 gears a step backwards, especially having a 7k rev limit. the UK classic 5speed felt spot on for his set-up.

having said that, his car is a daily driver so apart from the odd 1/4 event(standing start) it should not be a problem for him as a compromise as long as it lasts.

I think my car(UK) would suit the 6speed better . I am not into the straight line stuff and find 2nd a bit too high at times.

Mike555

Are the 6mt totally diffirent of the 5mt? Maybe some parts can change, like the 4th gear? :d

GDBSTi

In my experience the gears themselves are strong once selected however the gates are not well "defined" and therefore it is easy to damage a selector or synchro especially 5th gear. Maybye a Ferrari style gate control would help. I only found one car magazine review that noticed this, I think it was Car and Driver (USA). The selectors have nylon edges on there tip which can easily be broken resulting in a gearbox overhaul due to chunky gear changes.

A standard STi is more prone to this problem due to having to chase gears to keep the car on the boil. With the wider torque curve of a modified STi, gear changes can be slower resulting in less chance of damaging synchro's and selectors.

rupert

hunlimo

I drive a GC8 with a 6 speed box with paddle clutch, so far I havn't had any problems with it, and I do abuse it. The car is approx. 400HP using one of Andy F's turbos at 1.7bar, I do a lot of standing starts with it, as I participate in Drag races in Hungary. I broke the normal 5 speed box 5 times.

The gearing is a bit bad, and even worse in mine as I have the Jap spec box with c.diff and the 6th gear ratio is 0.842 so it is a bit short, I would guess if somebody made an end ratio of say 3.5:1 instead of the 3.9 it would help a lot.

Anyway I've tried leaving out 2nd gear, but it didn't help I ran nearly the same time as I do switching through the gears.

M0NEY

Interesting.

Are there ways of changing the ratios or is this a pain in the ****?

Would a skyline gearbox fit into a scoob? I heard someone was going to do it and not sure if they did but i thought they were just talking sh*t.

David Wallis is running a 6speed aint he?

john banks

Adam and I have been discussing this off line a bit, with the UK six speed you can still hit about 200 mph with an 8000 RPM limit.

If you are overtaking and have more than adequate torque and think you'll struggle to grab the next gear without hitting the rev limiter whilst looking out for the torque steer as you pull out (better if both hands are on the wheel), then use a higher gear.

I was already doing this with the UK 5 speed - used to drop to second at 40 or 50 to overtake something on the 2.0, left it in 3rd or even 4th on the 2.5 (third is potent enough to double your speed in 3.5 seconds from 40 mph with a passenger and full road trim and Aircon/spare wheel/tools/amps/sub etc), also changes the style of your overtaking - you tend to pull out, get the front wheels straight and only THEN floor it, so that you don't get pulled into the offside hedgerow. Does make it a bit safer because you get a good view before you go for it. I think this is how the advanced driving people teach anyway, but a surplus of torque makes it a lot more practical than the way a lot of people overtake where they are getting some torque down before pulling out.

Comparing the six speed to the five speed, I think I will just have an extra gear which is second which I will treat like gear "1.5". Otherwise 6th is like 5th, 5th like 4th, 4th like 3rd, 3rd like 2nd. I'll report back on how it is to drive once the gearbox is run in.

I may lose 1/2 second on the quarter from another gearchange? However, the terminal is more interesting in assessing your car so that you don't have to brutalise the drivetrain all day to get that 1.6s 60ft time

[Edited by john banks - 1/11/2004 2:15:47 PM]

M0NEY

I know you havent tried it (or have you ) but will you be able to hit 8000rpm? I thought someone told me that rev limit is only 7250 on the 2.5 sti?

TonyBurns

iTrader: (3)

The standard uk STi has its ratio's upto 183mph @ 7000rpm so its pretty good (taken from subaru uk website for mph per 1000 rpm).

Tony

john banks

Adam's engine should rev to 8000 though?

M0NEY

Sorry though you was talking about your engine. Me bad.

Tony, that sounds pretty good

911

Let me try to understand all this.
My STiV3 will pull 8000rpm. I've just fitted an Ra trans/Rr diff with a 4.11 diff ratio. The car is hill climbed, so does drag starts.
I'm expecting the box to go bang as I go to very soft slicks this year in competition, so lot more traction.

When it does go bang I was thinking of a Lateral gear cluster untill all the issues several of you are experiencing.
Next up is the TEG/Modena gear set @ a whopping £4.5K + fitting(!!)
So, then next up (today) is the STi 6 speed, and I've just found this thread....

If I take the STi 6 speeder and my 8000 rpm (314 bhp/280 lb ft)engine, will I get better on track hill climb performance compared to the 4.11/RA box?
If so is it an 'easy' fit John, clutch/CV's/prop etc?
Graham.

john banks

Can't say about the fitting to STi 3, but fitting UK six speed to MY00 UK can use the original 3.5 rear diff, needs a shortened propshaft by a few inches.

You'll need to look into fitting issues and gearing on your STi, but since you are running about the factory power and torque of the six speed STi (300 and 300 with PPP or US STi) then it should be up to the job?

For competition use are you better with a dog box?

[Edited by john banks - 1/11/2004 4:44:05 PM]

Pavlo

The 6 speed will be like an RA box with an extra gear.

Paul

ustolemyname??stevieturbo

iTrader: (1)

If you have an STI3, then a big diff will bolt straight in.
Get a box+diff+gear linkage from a Jap spec STI 6pseed, and both box and diff will bolt straight in ( assuming your STI3 has large rear diff and shafts ). Jap spec cars use 3.9 CWP front and rear. and have shorter rations for 4th 5th and 6th I think.
UK still uses the step down centre, with 3.9 front, and 3.54 rear.

Im not sure if the proshaft is different on the big diff models, but on a normal R-160, all thats needed is the proshaft from an automatic car, or you can get your own modified.

It really is a straightforward bolt on job.

Bob Rawle

There is not really enough info around on the six speed robustness yet, I think GadgetDaz is possibly running one of the highest torque cars, Dave W also has one in his car, mine is pretty "puny" at the moment comparitively. I do think, like John, that this box is going to be very good.

I can't understand why the ratios are considered so wrong, having driven both old 5 speed and JDM six speed "alot" I know which I prefer, with a slightly higher 6th than my 5 speed 5th and the others in between the JDM six speed suits me almost perfectly, 4th is an awesome gear, I've optimised my boost response on that gear then used the gear wastegate compensation to flex the rest.

You do need a 8000 rpm limit though, given that, I think its pretty unbeatable on the road, sprinting would be something else though.

911

Thanks for the reply everyone.
I am mostly interested in track (hill climb) performance, not road 'effectiveness'The STi I have is pleanty for the road.
A hill climb start = 5000rpm, dump the clutch. I can pull 2.1 seconds for the first 64 feet, close to 1G accelleration on Toyo's. Love to know how John gets 1.3 secs for the 60 feet?
From these comments it seems that the 6 speeder is a good bet. How much do you think a box/diff costs new/second hand?
Not too sure what the 'big diff in the rear' means other than a larger housing than the RA /STi ones I have.
If i have to mess around with diffs then i might as well go for a dog box in my RA case?
Any thoughts?
Graham.

Bob Rawle

1.3 is really v good and should have resulted in a sub 11.5 sec quarter, the figures below are from UK STi 8 using the std UK spec six speed (one extra gear change to the 5 speed). Std engine however similar spec to GadgetDaz.

0 - 60 ft 1,565 sec
1/8 mile 7,436 sec
" " 91,65 miles
1/4 mile 11,765 sec
" " 111,9 miles

This from Iceland .. all comments welcome ... bhp estimates anyone ?

bob

john banks

Graham, mine is only 2.1 approx best with a few tests in the wet with AP22. Andy says to subtract 0.2 from this for drag times so 1.9 because of how the beam is triggered apparently and his earlier results cross referenced. In the dry it might get to 1.7 perhaps, but I am not intending to brutalise it more than that.

john banks

Very nice times from Halldor. About 400 BHP from a 2.0? Maybe a bit more if a heavy body?

[Edited by john banks - 1/11/2004 5:46:37 PM]

Mike555

I think the ratio is different in USA, UK and The Netherlands (my place). If I am not wrong the Netherlands STI has long ratio, this will be very nice. Maybe it is an idea to put some long ratio gears in the 6 speed.

David_Wallis

911..

I know someone that bust a modena in their rally car.. (not sure if it was dog though.. seem to rememeber it tried to engage two gears at once when going from gravel to tarmac..

David

M0NEY

Seen a couple go for about £1400 but even then they are very rare!

Is there quite a lot of difference between the UK 6 speed and Jap 6 speed then?

john banks

If anyone has a good condition UK six speed for £1400 they will have limbs bitten off in the rush to get it.

There are more hassles making the JDM work because of rear diff mismatch, plus the top two ratios are short for most people's liking, especially with a 7000 RPM limit, most late cars with 8000 RPM limits already have the stronger boxes.