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

 

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.

 

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 :thumbup:
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

 

As a reminder - here is a good shifter rework thread:

http://www.alfaowner.com/Forum/alfa...6-andamp-gt/317383-how-to-fix-stiff-sticky-gear-problem-bushes.html#post4565652

 

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:
http://www.alfaowner.com/Forum/alfa-gta/175845-nitrous-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.:thumbup:

 

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

http://www.alfaowner.com/Forum/tuning-andamp-upgrades/889465-out-of-room.html

 

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 :biglaugh:

I think i best start selling all my spare parts i seem to have collected alot