Fiat Coupe Forum
- Funded by the Club for the benefit of all owners
- Please consider joining the Club to help keep the Forum running
- Or you can choose to make a Donation
Fiat Coupe Club UK
join the club
Fiat Coupe Forum
 
» Announced
    Posting images


» Related sites
    Main club site
    fiatcoupe.net

 
Who's Online Now
1 registered members (Robski1337), 1,372 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums48
Topics103,723
Posts1,170,144
Members1,659
Most Online39,516
Apr 16th, 2026
Top Posters(All Time)
barnacle 33,794
stan 32,123
Theresa 23,347
PeteP 22,311
bockers 21,083
Edinburgh 18,920
JimO 17,919
Nigel 17,386
Previous Thread
Next Thread
Print Thread
lower diff ratio 16VT 5 speed? #522841
16/01/2008 14:36
16/01/2008 14:36
Joined: Dec 2005
Posts: 1,897
New Zealand
Saint Offline OP
My life on the forum
Saint  Offline OP
My life on the forum

Joined: Dec 2005
Posts: 1,897
New Zealand
The coupe is magic for unrestricted cruising, however for track days and the road the gears are just a bit to long.

Someone suggested to me perhaps a tipo diff head (crown and pin) or a thema etc might fit into the coupe 5 speed box and have a lower factory ratio - assuming they share the same gearbox, maybe even an N/A 16v coupe

Anyone researched this?

the LSD on the coupe is outside the box so could this work to lower the ratios I guess?

Cheers


Re: lower diff ratio 16VT 5 speed? [Re: Saint] #522844
16/01/2008 14:41
16/01/2008 14:41
Joined: Dec 2005
Posts: 12,312
Sandhurst
Begbie Offline
ex El Presidente
Begbie  Offline
ex El Presidente
I AM a Coop

Joined: Dec 2005
Posts: 12,312
Sandhurst
I used to run a tipo sedicivalve gearbox and was a close ratio box, only trouble with that, is that it uses a push type clutch (although could be converted to pull) and you needs rods to operate the gearbox


Originally Posted by Jonny - After being taken out at Spa
Your car is Usain Bolt with wellies
Re: lower diff ratio 16VT 5 speed? [Re: Begbie] #522874
16/01/2008 15:32
16/01/2008 15:32
Joined: Dec 2005
Posts: 1,897
New Zealand
Saint Offline OP
My life on the forum
Saint  Offline OP
My life on the forum

Joined: Dec 2005
Posts: 1,897
New Zealand
Are all tipo sedicivalve gearboxs close ratio or was that a special


Re: lower diff ratio 16VT 5 speed? [Re: Saint] #522876
16/01/2008 15:35
16/01/2008 15:35

R
Robi_hr
Unregistered
Robi_hr
Unregistered
R



The closest ratio gearbox is the lancia dedra 1.8 and tipo 1.8 16v but that are rod operated gearboxes and are much much smaller and weaker than the coupe 16vt ones. You could use the croma 2.0 16v gearbox internals.

Re: lower diff ratio 16VT 5 speed? [Re: ] #522881
16/01/2008 15:45
16/01/2008 15:45
Joined: Dec 2005
Posts: 1,897
New Zealand
Saint Offline OP
My life on the forum
Saint  Offline OP
My life on the forum

Joined: Dec 2005
Posts: 1,897
New Zealand
are the croma gears just as strong etc and do you know what the ratio is?


Re: lower diff ratio 16VT 5 speed? [Re: Saint] #522883
16/01/2008 15:48
16/01/2008 15:48
Joined: Nov 2006
Posts: 1,580
Melbourne, Australia
Scuderia Offline
My life on the forum
Scuderia  Offline
My life on the forum

Joined: Nov 2006
Posts: 1,580
Melbourne, Australia
16V and 16VT use quite different gearboxes. 16V is like a Tipo 16V. 16VT is like a Thema or Integrale. The internals dont mix afaik.

You could swap the whole gearbox but the 16VT type box is ment to be a lot stronger. Although ive never had any trouble with my 16V based gearboxes.

At a guess a Thema/Croma etc would be the same or worse. Integrale would be the best bet to look up.






Re: lower diff ratio 16VT 5 speed? [Re: Scuderia] #522955
16/01/2008 17:22
16/01/2008 17:22

S
sediciRich
Unregistered
sediciRich
Unregistered
S



There is no doubt to what steve has said, the boxes are very different I would say the coupe box is the same as the alfa v6 box (not sure). I have ordered all the parts to convert my tipo box to cable shift which will use the same cables as the coupe. Using parts from 146 gamma 1.6TS. That box is the same as tipo 16v. I used a multipla final drive and (CW and Pinion) correct me if Im wrong but the pinion is on the output shaft so you have to dissassemble the box to change the ratio?? I got someone to rebuild mine. In fact I will be taking out that Final drive and gear kit as I have just bought Bacci Romano gear kit 13/53 final drive and LSD - wow thats expensive plus 20% tax. I would think that taking the cover off the turbo diff housing and comparing the crown wheels would be the only way. or look at catalogues to see if there's commonality.

Re: lower diff ratio 16VT 5 speed? [Re: Saint] #523200
16/01/2008 21:25
16/01/2008 21:25

R
Robi_hr
Unregistered
Robi_hr
Unregistered
R



Originally Posted by Saint
are the croma gears just as strong etc and do you know what the ratio is?


don`t know the exact ratio but everything is as strong as the coupe and you can swap all of the parts into yours gearbox, you could also use the parts from stilo abarth gearbox, alfa v6, thema 2.0 16v/t. The best way to know the ratio is to take of the diff cover and count the teeth

Last edited by Robi_hr; 16/01/2008 21:29.

Powered by UBB.threads™ PHP Forum Software 7.7.1
(Release build 20190129)
PHP: 7.4.33 Page Time: 0.013s Queries: 14 (0.008s) Memory: 0.6251 MB (Peak: 0.6964 MB) Data Comp: Off Server Time: 2026-10-11 23:05:36 UTC