Register Login
Shop4Parts - UK's largest online superstore for FIAT and Alfa Romeo parts
Reply
 
Thread Tools Search this Thread
Old 08-10-2020   #16
Join Date: Sep 2020
Posts: 12
Thanks: 0
Trader Rating: 0
Poland 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Thankfully most of the time it's only me and my lady (no floosies anymore - going to get married soon! ) and to be frank hauling more than four buttocks on board rarely happens, 3dr is useless in this aspect comparing to 5dr, not mentioning the trailer and such.

But there is a point - it's still about sacrificing some things to favour the others so it's not a perfect solution by any means. I was also thinking about switching the 5th gear ratio only buuuut the outcome would be four reasonable gears and one overdrive gear, usable only on highways, there would be also this massive revs drop between 4th and 5th so again - lots of pros and cons.
6-speed box looked like an ultimate solution for all these cons but... Ralf S. has told lots of smart things about this idea and one thing hit me - I agree with the fact that Thesis is more akin to Alfa 166, a higher tier car, but Alfa 156 also featured 5 cyl engine with 6-speed box (2.4 JTD versions).
Fiat Coupe? Same thing, 5 cyl paired with 6-speed box and Coupe has even narrower track width (1491mm to 1514mm in Stilo).
I'm helluva confused...
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

TheWeathers is offline Reply With Quote Quote 
Old 08-10-2020   #17
Join Date: Apr 2005
Location: South East
Posts: 2,726
Thanks: 180
Trader Rating: 0
Yellow Peril has donated!
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Quote Originally Posted by Maxcaddy View Post
an easy alternative would be to simply increase the rolling radius of the wheels by using bigger tyres.
Hmm. The Schumi is already on 18" wheels. Any bigger would look hideous in my view...
__________________
Phil
Yellow Peril

Then:Yellow Stilo 1.6 16V 3-door - not quite standard
Now: Red Stilo Abarth Schumacher GP Prodrive - modded for function over form...
Yellow Peril is offline Reply With Quote Quote 
Old 08-10-2020   #18
Join Date: Sep 2020
Posts: 12
Thanks: 0
Trader Rating: 0
Poland 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Quote Originally Posted by Yellow Peril View Post
Hmm. The Schumi is already on 18" wheels. Any bigger would look hideous in my view...
I already have flashbacks from early 2000's Pimp My Ride projects thinking about this

You could leave your 18" on but fit higher profile tyres on em. I bet tyres on 18" have thickness of a stepped-on bubble gum (if you're keeping the rolling radius the same while increasing the rim size) so put something thicker in there, like 70 instead of 30/40 profile and here you go. Rim size doesn't matter itself, it's a combination of rim size and tyre profile.

But then you're going from sporty look towards the minivan look
Likes Maxcaddy liked this post
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

TheWeathers is offline Reply With Quote Quote 
Old 09-10-2020   #19
Join Date: Dec 2003
Location: The land that time forgot
Posts: 3,244
Thanks: 250
Trader Rating: 0
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

The problem with increasing the tyres' aspect ratio is the size of the tyre. If you go from 215/45x17 to 215/60x17, the diameter of the tyre goes up from 62cm to 69 cm... so it's 3.5cm closer to the wheel arch, and the bottom spring plate of the front damper. It may just not physically fit.

Somewhere between 215/45 and 215/60 there is probably a size (215/50?) that will not foul the damper or the wheel arch, or the wheel arch liner (ask someone to turn the front wheels from lock to lock and see how much clearance you have now) but as with the gear ratio's, it might be a lot of expense (new tyres) for just a minor improvement.

If the gearbox idea doesn't check out, then swapping the 5h gear ratio is not completely out of the window. It depends on the relative ratio between the 5th gear on your gearbox and the one on the replacement gear cogs.

I swapped the 5th gear cogs on my Alfa 145 T/Spark 1.8 to use the JTD 5th gear.
The 1.8 gearbox and the JTD gearbox just happened to have the same sized shafts and the 5th gear of the Alfa 145 gearbox is accessible under a cover, so it didn't need the gearbox removed.

Anyhow, the standard Mainshaft gear (37T) and Countershaft gear (35T) gave a Final Drive = 0.946

The Mainshaft gear of the JTD (39T) and Countershaft gear (31T) gave a Final Drive = 0.795

That dropped the rpm from 4000rpm at 80mph (indicated) to just under 3600rpm, which was useful. The 1.8 engine did feel like you were changing up from 4th to ~5.5 but in normal driving, after you get used to the sensation that you missed a gear, is actually okay. The 2.4 is more torquey still, so you'll only notice the change in engine tone, rather than acceleration.

But it depends on the gear ratios fitting onto your existing main/countershafts. The Alfa JTD box was based on the T/Spark box so that was lucky... but you need to make sure before you spend a load of money.

The only other funny part (now) is that I bought just a mainshaft cog thinking it was going be all I needed... €100 was just about worth it.. then I was sitting on the toilet looking at it.. and I realized I'd also need the countershaft cog.

So that cost me twice what I thought.... (brand new Fiat/Alfa gears, since the Alfa JTD box wasn't imported to the UK).

If you can find a cheap donor gearbox, it'll be easier to dismantle that and just see if the parts fit. Otherwise, check the part numbers for the mainshaft and countershaft.. they could be identical, in which case you'll know the JTD cogs will fit into your 2.4 gearbox. If the part numbers are different... that's not necessarily bad news... they could just be slightly longer or shorter etc. but the diameter and spline spacing may stil be identical.

Ralf S.
Likes TheWeathers liked this post
__________________
No bullets for chaingun
Ralf S. is offline Reply With Quote Quote 
Old 09-10-2020   #20
Join Date: Sep 2020
Posts: 12
Thanks: 0
Trader Rating: 0
Poland 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

I took a look at the gear ratios for 2.4 and the JTD 115 version, see below:

Gear ratios (overall):
2.4:

I 3.8 (13.53)
II 2.24 (7.97)
III 1.52 (5.41)
IV 1.16 (4.13)
V 0.91 (3.24)
Final drive ratio std: 3.56



JTD:

Gear ratios (overall):

I 3.577 (12.98)
II 1.887 (6.85)
III 1.192 (4.33)
IV 0.848 (3.08)
V 0.686 (2.49)
Final drive ratio std: 3.63



Seems like a massive difference but I have no experience in such modifications so no idea how it would work out.
I think I'd be OK with using 5th as an overdrive gear because in real life, crusing around the city at 30-35mph requires driving on 4th, only outside the city I pop in the 5th, 55mph at 2500rpm.

Can I somehow imagine myself or calculate what revs I'd get throwing in the 5th from mentioned JTD gearbox?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

TheWeathers is offline Reply With Quote Quote 
Old 14-10-2020   #21
Join Date: Dec 2003
Location: The land that time forgot
Posts: 3,244
Thanks: 250
Trader Rating: 0
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Have a look at this site:

http://wallaceracing.com/calc-gear-tire-rpm-mph.php

I've tried it out. Based on a 215/45x17 tyre, if your 2.4 does 3500rpm at 80mph, then a JTD ratios (if the actual gears fit, or if you just fabricated new gears with the same ratio) would give you 2720rpm.

If your 2.4 does more than 3500rpm at 80mph, then I've used it wrong...


Ralf S.
__________________
No bullets for chaingun
Ralf S. is offline Reply With Quote Quote 
Old 14-10-2020   #22
Join Date: Sep 2020
Posts: 12
Thanks: 0
Trader Rating: 0
Poland 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Quote Originally Posted by Ralf S. View Post

If your 2.4 does more than 3500rpm at 80mph, then I've used it wrong...


Ralf S.
I think you did it correctly, 2.4 has around 3500rpm at 80mph so dropping it down to 2700 would be MASSIVE improvement
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

TheWeathers is offline Reply With Quote Quote 
Old 16-10-2020   #23
Join Date: Sep 2009
Location: Bembridge
Posts: 143
Thanks: 8
Trader Rating: 0
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

[QUOTE= or if you just fabricated new gears with the same ratio
Ralf S.[/QUOTE]

Assuming of course that most folk have a gear shaper/hobbber/grinder stashed in their Shed
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Maxcaddy is offline Reply With Quote Quote 
Old 18-10-2020   #24
Join Date: Oct 2020
Posts: 5
Thanks: 0
Trader Rating: 0
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Does anyone know where the reverse light switch is located? Pictures would be helpful. Thanks!
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

arunj is offline Reply With Quote Quote 
Old 20-10-2020   #25
Join Date: Sep 2009
Location: Bembridge
Posts: 143
Thanks: 8
Trader Rating: 0
United Kingdom 
Re: Stilo GT - 5spd manual to 6spd manual gearbox swap from Lancia Thesis?

Quote Originally Posted by arunj View Post
Does anyone know where the reverse light switch is located? Pictures would be helpful. Thanks!
Does it's location interfere with a 6 speed box being fitted then ?, if not the relevance is ?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Maxcaddy is offline Reply With Quote Quote 
Reply
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump
Similar Threads
Thread Thread Starter Forum Replies Last Post
(G) Fiat Stilo service manual, repair manual and workshop manual Old Hippy Stilo 38 02-12-2017 22:47
(T) Feasible to swap ZF 4 speed auto gearbox for manual adamlipscombe Ducato 5 06-10-2017 21:44
(G) Manual Gearbox swap Mr Clock Radio Punto (Mk2/2b) 2 20-10-2016 20:32
(T) stilo abarth swap to manual skazo4nik Stilo 1 17-09-2015 13:02
500 Red 2011 demo, 1.4 16V Lounge 6spd manual Little Red Chinky Members Motors 6 02-09-2012 20:05