6 speed gearbox Alfa upgrade

hi friends

I want to have a little more reactive car beacuse the car, after a turbo upgrade (GT2560R), suffers of a little annoying lag (boost at 2800 rpm).

I found a very cheap 6 speed Alfa 166 2.5 v6 gearbox with 100.000 km at 150 €.

Can this gearbox with perfeclty on my car?

my actual gearbox have this ratios:

Fiat Coupe 20vt 5 speed:
1st Gear ratio 3.8:1
2nd Gear ratio 2.235:1
3rd Gear ratio 1.52:1
4th Gear ratio 1.156:1
5th Gear ratio 0.914:1
Final drive (diff) 3.111:1

so final reducion in 5th is 2,843

and the Alfa:

Alfa 156 V6 2.5 6 speed:
1st Gear ratio 3.5:1
2nd Gear ratio 2.235:1
3rd Gear ratio 1.52:1
4th Gear ratio 1.1613:1
5th Gear ratio 0.971:1
6th Gear ratio 0.816:1
Final drive (diff) 3.9375:1

so final reduction in 6th is 3,213

I want to have the final reduction of my actual 5th gear on the new 6th gear but I have to find a final drive around 3.5:1.

is this possible at a reasonable price?

PS = I know that final drive around 3,5:1 is in the Lancia K 20v Turbo and in the Alfa GTV 3.0 v6

many thanks for your support

ciao

Really not sure that the Alfa gearbox will bolt up directly to the 20vt gearbox.

Someone else might know if you can replace the gear set into the 5 speed Fiat box - certainly if you have the 6 speed Fiat Coupe gearbox, you can swap over the internals from the Alfa 156 V6 box because that's what I have in my kappa

Would have thought if the 6 speed Fiat casing was same as 5 speed, we would have noticed and I would not have to buy a new one when I broke the casing

Alfa 156 2.5V6 6 speed innards into a 20VT 5 Speed will work. LiamM has just done this. See Below....



His 20VT Race Car Discussion thread is here!

this is just what I wanted to hear !!!

grazie !!!

hangar, vuol dire che possiamo mettere il 6 marce Alfa sotto i nostri turboni!?

Gimmo, I answer in english we are in UK here !!!

I'm almost sure yes!

I will sacrifice the top speed (not needed at all...) for a better handling

Now I have to ask to my favorite garage....

http://www.mariottiracing.it/mariotti/index.php?option=com_content&view=frontpage&Itemid=1

stay tuned...

Gimmo, please, non rubarmi il mio cambio !!!

No problem I don't want to steal your gearbox!
I want to buy an Alfa 155 Q4
Maybe I will take it next week, and I will remain with no money

So, keep in touch and please, update this topic, I'm so curious!

It will only work in the 156 type 5 speed not the early 5 speed.

hi Scuderia

what means?

I dont want to change only internals...

I want to install the whole gearbox Alfa with diff in place of mine 5 speed gearbox

That wont work as the bell housing is different. Only option is to use a Coupe (20VT 156 style 1998+) bellhousng and assemble the alfa 2.5 gearset into it.

Hi there

I had a 5sp 20vt (the late box type) and put a 156 V6 Gearbox in with a coupe bell housing.

Works perfectly....

good for you!

but this transplant is a little too expensive for me now!

my garage asked me around 450 € and to this you have to find a good alfa gearbox...

moral of the story: better find a 6 speed gearbox from Coupe and change the final drive to 1:3,5

It's an easy enough swap, should only take a few hours, it will totally transform the car, I need a decent LSD for mine now more than ever!

or get an alfa 147 diesel 6speed gearbox even better q2 gearbx

Nismo has a 6 speed gearbox for sale, I've contacted him!

I hope to have a positive conclusion ...

after this I have to find final drive 16 / 57 teeth (3,563) from alfa 156 2.0 twin spark engine or gtv 3.0 v6 24v

I hope to not sell a kidney to buy these two gears....

finally has arrived !!!

I bought a 2001 6 speed gearbox and I'm almost ready to make the swap; I have also the selector with reverse gear inhibitor.

As above I need to change final drive, two solutions for 16/57 teeth for a 6 gear

- Alfa 166 2.4 jtd 6 speed
- Alfa GTV 3.0 v6 24v 6 speed

this is the dropbox link of my calc file (sorry for the italian)

https://www.dropbox.com/s/uho262g917d37wb/rapporti%20cambio.ods?dl=0

if there are some mistake please advise

ciao !

my project is in advanced stage !

- I bought a 2nd hand gearbox Alfa 2.4 jtd 6 speed
- I sent both gearboxes to my favorite garage for the transplant

interesting that 1st, 2nd, and R internals are the same of the Coupe

other interesting note: the 2 gearbox bellhouse are identical also in the flange area

this has been confirmed by guys in the garage, so why to be crazy to find a 6 speed gearbox from Coupe when you can buy a cheaper 6 speed gearbox from Alfa models?

I will keep you updated this important upgrade of my car

Really?
A 166 gearbox Will be direct-fit under the Coop?

Well, is that 100% correct????
Never compared it side to side but heard a lot that they different....

when the two gearboxes will come back I will post some pics to reveal the mistery....


true or false ? make your bet

It's true.... the only difference is in the right gearbox mount support. But I can tell you a secret... If you use a support mount from 1.9 jtd alfa 147 and fiat original pad everything will come on place. I am with 5 speed gearbox from diesel at the moment with the mentioned upgrade. The only problem is that the 3-4-5th gears are way to long for a petrol engine and the car feels really slow...
1st and 2nd are the same...3th on 8000 rpm is 210 kph 4th 294 kph and 5th theoretical is 390 kph

Joro20VT

--
I am with 5 speed gearbox from diesel
--

so, a quick shifter made for an Alfa will go under a Coupe?

Yes, but only 5cyl.

PROJECT FINISHED !!

now I have completed 5 to 6 gears swap changing final ratio from 17/54 teeth (stock for our 6 speed cars) to 16/57 teeth

the car is (in my opinion) much more reactive (especially going out form the roundabout)

so this is the final balance:

- used Coop 6 speed gearbox (with 1 synchronizer broken)
- used Coop 6 speed selector
- new 6 speed gearbox support
- used Alfa 166 2.4 jtd 6 speed gearbox
- fully refurbished 6 speed gearbox with new final drive
- swap in gearboxes

all the work tooks 1320 €

now some pics (quality not perfect)

used 6 speed gearbox



6 speed gearbox refurbished


6 speed gearbox refurbished


working on the car


working on the car


working on the car


me and the car after the surgery !!!

Any info?

sorry cant confirm 100%

I didn't have had time to check in the detalis everything

they seem identical if I look at the bell

I can confirm that:

- the internals are interchangeable
- the diff alfa does not provide viscodrive installation
- you can swap 6 speed primary and secondary shaft only with 6 speed shaft of course

more info here:

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=1312796

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=875370

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=859626#Post859626

bellhousings are the same I have 6 speed coupe box fitted to 2.4 20v jtd

Hello my friends. I put the 166 Alfa 6 speed gearbox to the 20vt engine, But i need the gearbox mount support from the coupe 6 speed. The alfa 147 mount support is too long, the other support from the 2.4 JTD marea is to short. I build a 6 speed(VLSD) 20V Turbo HGT in Hungary