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(Post Link) post #1 of 14 Old 16-09-15 Thread Starter
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Gear stick return & Wheel size Question

Hi Guys


1st question. How can i make the gear stick more firm in its return to center as i guess it will be worse once ive done the gear selector short shift.

2nd question. After reading all you gear ratio posts i guess the 2.5 box is the best to use except as pud mentioned gear change has to be done at 57mph.
This car is being built for straight line road legal drag so 0-60 and 1/4 mile are the results i need to be the best it can be.
So im wondering as im using 18" wheels 225 40 18 tyres will the extra size make the ratio so that it will be over 60 mph when i need to change gear.

Opinions please on what you think will be best for me, even including maybe taking gears from other box's and having a custom gearbox. as i will be stripping my spare gearbox down and rebuilding anyway.

Car info 156 running 3.0 Engine 9:1 compression ratio with Turbo running with 8 to 10 psi

Thanks in advance

All spares parts for 156 and 147 being sold that i will not be using (cheap) nothing too small ask what you want , willing to post world wide Phone 07922123242 Ask for Neil and say Mark said to phone .

Download link for Alfa 156's http://www.filedropper.com/alfaelearn
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1st question - not sure there is much you can do there

2nd: To go from 57 to 60 mph shift, you'll need 5.3% bigger circumference wheels. The guidelines say you should keep the size difference to 3%, but I think 5.5% should be OK. Between the stock options 205 55 16 / 225 45 17 / 225 40 18 there is less than 1% variance. You'd have to go to 225 50 18 to make a significant difference.

To change gears in not quite as easy as you'd think as the gears are rather tightly mated on their shafts. Now the difference between the 2.5 , 3.2 (GTA / GT) box , the 3.0 GTV box is ONLY in the final drive - still you'll need the whole secondary shaft and the crown gear (see point 1). There is a 7% increase between the drives (for the ease of remembering - the 2.5 box red-lines in 6th at 160mph, the 3.2 box at 175mph, the 3.0 box at 186mph). The Diesel box has the same internal config, just another bell housing. It has longer ratio jumps with 1st the same as all the rest, but 2nd, 3rd, etc are incrementally longer and it comes with the 3.0 GTV final drive - that said it should hypothetically red-line at 250mph if put in a petrol box.

All said: if 0-60 without shifting is your aim, then fit the 3.0 GTV box. If your aim is 1/4 mile times, then stay small ratio - 2.5 box. If you are aiming for top speed world record, go diesel internals
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Quote:
Originally Posted by Gertie View Post
Between the stock options 205 55 16 / 225 45 17 / 225 40 18 there is less than 1% variance.
True, but there is a step up between the OEM 17" size for the 2.5 (215/45R17) and 225/40R18.

Last edited by David C; 16-09-15 at 17:54. Reason: Edit for obvious error putting 17 instead of 18...
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(Post Link) post #4 of 14 Old 16-09-15 Thread Starter
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Thank You for the reply .

Very well explained , And i think i shall keep the 2.5 box as thats whats in the car at the moment. I will see how that runs and then keep my eye open for a cheap GTV box to overhaul . Im sure i will break the 2.5 box as its an old high mileage 1 thats just for the testing.

Nice 1 that sort that out
o

Edit that why waste money i have 3 very good 2.5 box's all only about 50-75k so i will stick with them unless a very cheap GTV box pops up

Thx again

Last edited by mirlock; 16-09-15 at 16:47.
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Quote:
Originally Posted by David C View Post
True, but there is a step up between the OEM 17" size for the 2.5 (215/45R17) and 225/40R18.
215/45 is such an odd size it is 1.04% smaller that the 16's where the 225/45 is 0.34% bigger than the 16's. I have not asked for price, but I'm sure it is more expensive as it is not a popular size.

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Originally Posted by mirlock View Post
Im sure i will break the 2.5 box as its an old high mileage 1 thats just for the testing.

Edit that why waste money i have 3 very good 2.5 box's all only about 50-75k so i will stick with them unless a very cheap GTV box pops up
If you don't have a Q2 / Quaife it will most probably be the diff that explodes before any main gearbox part, still you having extra boxes are a good thing.
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Quote:
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215/45 is such an odd size it is 1.04% smaller that the 16's where the 225/45 is 0.34% bigger than the 16's. I have not asked for price, but I'm sure it is more expensive as it is not a popular size.
It is odd, but 215/45R17 was the OEM 17" size on "normal" 156/147/GT, with 225/45R17 only listed for the 3.2V6 versions. (although 215/45R17 is listed as a chainable option for the 3.2).

225/45R17 is normally cheaper and is what I'd be using too, but not due to price alone.
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(Post Link) post #7 of 14 Old 17-09-15 Thread Starter
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:



If you don't have a Q2 / Quaife it will most probably be the diff that explodes before any main gearbox part, still you having extra boxes are a good thing.
Ive got a Quaife but didnt want to mess it up while testing , So im fitting it to the gearbox that im stripping down and cleaning etc. fingers crossed with advise from you guys after sorting any problems i may face i should end up with a good car
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As a reminder - here is a good shifter rework thread:

https://www.alfaowner.com/Forum/alfa-...ml#post4565652
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Quote:
Originally Posted by mirlock View Post
Hi Guys
This car is being built for straight line road legal drag so 0-60 and 1/4 mile are the results i need to be the best it can be.
Road Legal Drag? you been watching Street Outlaws by any chance?

Reading about your 156 jogged my memory about another guy who did 1/4 mile racing but used nitrous to make the extra power allbeit on a 2.5 v6, he's "alfanitrous" on here and may have some interesting advice with his experience.

Here's a thread you may find of interest:
https://www.alfaowner.com/Forum/alfa-...ous-oxide.html

ps are you going to post up some pics in a 156V6Turbo build thread? its always interesting to learn how others have done their conversion.
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(Post Link) post #10 of 14 Old 25-09-15 Thread Starter
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Quote:
Originally Posted by jbsmith1 View Post
Road Legal Drag? you been watching Street Outlaws by any chance?

Reading about your 156 jogged my memory about another guy who did 1/4 mile racing but used nitrous to make the extra power allbeit on a 2.5 v6, he's "alfanitrous" on here and may have some interesting advice with his experience.

Here's a thread you may find of interest:
https://www.alfaowner.com/Forum/alfa-...ous-oxide.html

ps are you going to post up some pics in a 156V6Turbo build thread? its always interesting to learn how others have done their conversion.
Thx JB for link

As for thread i did start one when i started the project but i lost all my photos , But i am taking more as i go and when done i will do a new thread explaining all ive done


here is a pic of the engine so far , but still lots of changing to do

https://www.alfaowner.com/Forum/tunin...t-of-room.html

Last edited by mirlock; 25-09-15 at 17:02.
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there is a gear change repair kit for the fiat that looks similar to the alfa change.. stripped mine the other day and fitted new gear change cables
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(Post Link) post #12 of 14 Old 01-10-15 Thread Starter
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Originally Posted by maxiboy wales View Post
there is a gear change repair kit for the fiat that looks similar to the alfa change.. stripped mine the other day and fitted new gear change cables
Nice one Maxi ill get me one of them. seems to be never ending when i think im done buying i find something else to buy

I think i best start selling all my spare parts i seem to have collected alot
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Quote:
Originally Posted by mirlock View Post
Nice one Maxi ill get me one of them. seems to be never ending when i think im done buying i find something else to buy

I think i best start selling all my spare parts i seem to have collected alot
http://www.ebay.co.uk/itm/FIAT-LANCI...=item4182cac5b

that one...

yeah same here will have a few spares to shift at the end lol
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(Post Link) post #14 of 14 Old 02-10-15 Thread Starter
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Originally Posted by maxiboy wales View Post
http://www.ebay.co.uk/itm/FIAT-LANCI...=item4182cac5b

that one...

yeah same here will have a few spares to shift at the end lol

thx fellla
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