Six speed gearbox upgrade: GTV or 166? - Alfa Romeo Forum
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(Post Link) post #1 of 7 Old 22-09-13 Thread Starter
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Six speed gearbox upgrade: GTV or 166?

Hi all,

I got myself a new alfa this week. It's a 1998 3.0 V6 GTV in Proteo red with Cadamuro front and side spoilers, Alessio Euro alloys and the red dash interior. It needs a bit of tidying up, with a dent in the side and a crack to the bonnet, which I intend on sorting over the next few months. Also planning on swapping the alloys to something original.

In addition, the clutch is really very heavy. Whilst this is quite good as a workout, I thought I'd use it as an excuse to switch the existing 5 speed gearbox to a 6 speed. I have the option of a 6 speed from either a GTV or 166. I understand the final drive is 3.56 on the GTV versus 3.73 on the 166.

Can anyone give any advice as to which I should go for? I'm planning on using the car as a road car rather than track, if that influences things.

Thanks and best,

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I recall that one Ebay - was bit of bargain! BTW, those wheels are worth quite a bit of money and got a feeling they were 18" as well. Personally, I think they look superb and would get them refurbished as it suits the car.

Your clutch should not be excessively heavy!

Clutches and gear boxes are very reliable, a worn clutch will tend to bite at the top of its travel and as they are self adjusting. A high biting point signifies that a new clutch will be needed soon. The 3.0l clutch is a pull type clutch and can get quite heavy as the diaphragm work hardens, the cover does not then exert enough pressure on the friction plate and this may then slip. Gear boxes are generally trouble free, but do check that all gears engage smoothly without crunching, occasionally the nut comes loose on 5th gear and this can make 5th gear difficult to engage, however the nut only usually needs tightening which can be done with the gear box in situ.

Comments (above, taken from Alfa Workshop) and see here to:- Jamie Porter's Alfa Romeo GTV/Spider Problem Solving Guide

If you need to change the Clutch > convert to GTA spec with Light Flywheel, which would be worth doing IMO if you are changing out the gearbox.

Cannot comment on 166 gearbox, but I do know a guy who has a 156 6 speed in his GTV V6 - think it has slightly closer ratios??

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All 6 speed gearboxes have closer ratios than your 5 speed. 5speed V6 5th gear is longer than 6th gear on 2.5 V6 6speed (which is generaly the shortest of all the 6speeds) and about the same as the 6th on GTA and 166 6speed gearboxes. GTV 3.0 6speed is the longest in ratios amongst all the 6speeds, has the longest diff of all the 6speeds and is the longest on the top gear of all the V6 gearboxes.
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A heavy clutch is a sure sign that it will soon start to fail.

As suggested replace with a GTA clutch and flywheel - the dual mass one as fitted originally fitted is expensive and doomed to failure. Also worth considering a Q2/Quaife diff whilst you are there - it truly does transform the performance - bye, bye torque steer.

Even with the GTA clutch which is lighter it still feels weird when I drive the 2.0 GTV as the clutch pedal, initially, feels like there is no resistance whatsoever.
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(Post Link) post #5 of 7 Old 24-09-13 Thread Starter
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Thanks all for your help with this.

I think I'm set on the GTV 6 speed with GTA clutch and flywheel and Q2 diff!

Thanks PJ3074 for your comments on the alloys. Having paid a higher insurance premium for the year in view of the non-standard alloys, I think I'll be revisiting whether to switch them over to 17" Teledials come insurance renewal.

Cheers guys,

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Originally Posted by mhf86 View Post
Thanks all for your help with this.

I think I'm set on the GTV 6 speed with GTA clutch and flywheel and Q2 diff! mods EVER...
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I would go with a GTV 6-speed box, the 166 one has a different diff housing and you would need to use the old one off your 5-speed to make it fit, but the trouble with that is they are line-bored and don't always swap over so readily.
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166 , gearbox , gtv , speed , upgrade

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