View Full Version : Longer 5th gear - Q4 gearbox
Alfa Patch
28-05-12, 10:59
Hi Guys
Dave - did you find anywhere cheaper? I am keen to do this whilst the box is out of my car at the moment.
I am surprised more people havent done this? My car is standard and still has more power than it does gears, anyone with more power must have deft throttle control in order to cruise at motorway speeds.
Buy a 16vt 'box and remove the bits you need.
The ratios are certainly much taller so you'll have worse acceleration, but better cruise. I've seen 120mph in 3rd and 160 in 5th.
Steve Webb
02-06-12, 14:42
I've seen 120mph in 3rd and 160 in 5th.
Thats an awfully long straight on that private track! :unsure:
It was yes. The car wanted to go more and had it in it too - I didn't though, I was crapping myself. :blush:
Steve Webb
03-06-12, 13:01
I had a moment like that once, it was in my old Fiat 500 with the hot 126 engine. There was plenty of go left in the car, but it was going fast enough for me thank you very much.
75mph in a car designed in the 50s for Italian country lanes get pretty scary!
Alfa Patch
19-06-12, 08:45
Hi Evodelta. When you say 16vt box would a coupe one work? If not from what? I only want to change 5th and I know that'll leave me with a fairly big drop in rpm between 4th and 5th but I might be able to get around without having to buy a fuel refinery!! Thanks
Yes, I do mean Coupe 16vt. You would have to open one up to see what is what, but both stacks are very similar so some gears could be usable. It is probably the diff (not interchangeable) which gives the Coupe its overall higher gearing.
Today I order these gears from an Alfa Romeo dealer for 360 euros both. I hope the codes are correct. :P
Hi Guys
Dave - did you find anywhere cheaper? I am keen to do this whilst the box is out of my car at the moment.
Hi :wave:
I have not come around to order these yet, have so many things on the to-do-list that the money seems to run straight through my wallet :huhsign:
and this is not a high priority right now..
anyone else found a better price somewhere?
Steve maybe this would be an item for the Shop, it is a good (and easy) mod and as Alfa Patch says, even standard the car revs a bit too high on highway-speeds!?
Steve Webb
28-11-12, 20:59
Yes, I do mean Coupe 16vt. You would have to open one up to see what is what, but both stacks are very similar so some gears could be usable. It is probably the diff (not interchangeable) which gives the Coupe its overall higher gearing.
The Q4 and Coupe 16vt are quoted as the same top gear ratio of 0.92, however the final drive for the Q4 is quoted as 3.35, the Coupe 16vt 3.11 .
So it looks like the longer legs of the Coupe are all down to the final drive.
If anyone can confirm these new (expensive) gears work fine then I'll take a look at getting them in the shop.
Cheers
Well i canceled mu order because the one gear is not available by fiat in my country and they told me that it is posible to have it maybe in 5-10 months. I will take out The oem and i will go to someone in my place that is made racing gear boxes and gears and i will ask him if he can make the same gears with 30/37. I will inform you here when i have some news
Steve Webb
29-11-12, 20:57
Has anyone done the sums to work out what the mph/1000rpm would be with the 30/37 gearset?
maybe will help: I found that 155 2.5 TD, some versions of delta II 16vT, tempra and dedra 4x4, not all models, just some rare versions have this gear 30/37 gearset
Vedran
Has anyone done the sums to work out what the mph/1000rpm would be with the 30/37 gearset?
with standard gearset (33/36) gear ratio is 1 : 0.917 runs 35.418kmh/1000rpm (230.2kmh/6500rpm)
with 30/37 gear set gear ratio is 1 : 0.81 runs 40.108 kmh/1000rpm if i calculated correctly
(260kmh/6500rpm)
I just informed from Enrico that they produce these gears ( as he already have it in hi car) for 450 euro.....
Steve Webb
06-12-12, 15:32
Hmmm, not a cheap solution then.
Expensive enough. If i have time i will visit someone in next city who is building racing gearboxes. The only i am bored to do is to take out the stock gears to show them as a sample
i have found whole gearbox from 155 2.5 TD for 100 € :)
You are lucky :) if the the 5th gear is in good condition buy it
Steve Webb
07-12-12, 10:42
There are quite a few 155 2.5 tds over here in France, I'll keep my eyes open to see if any are being broken for parts.
Mind you It looks like you can get a complete car for @€400
If only I had the space to store one.
i have asked guy who sell this gearbox to check number of teeth from 5th gear to be sure it's 37/30 gearset. i'm waiting him to check. i hope it's correct gear set, and in good condition
The other day I bought 155 2.5 TD complete gearbox for 80 euros,it has 30/37 gearset, so today I have replaced gear and I can confirm it fit perfectly. some pics:
Steve Webb
15-12-12, 15:32
Isn't this the same gearbox that is in the 164 2.5td as well?
If so here is one for sale in France for €100
164 2.5td gearbox (http://www.leboncoin.fr/equipement_auto/290144378.htm?ca=2_s)
well, what can I see in pictures it's not same from outside, 155 have different mounting and shifting, but it may be same inside...
according to EPER, it has 31/43 gearset! too long I think. it will be too big diference between 4th and 5th gear
which gear set is 31/43? you mean from 164 2.5 TD?
The other day I bought 155 2.5 TD complete gearbox for 80 euros,it has 30/37 gearset, so today I have replaced gear and I can confirm it fit perfectly. some pics:
great info, i have on local ebay here about 6 of this gearboxes, from 75-150EUR each.. so probably i will buy one and ask seller to take this gears out and send to me, and he can trash everything else :D
regards
WS
great info, i have on local ebay here about 6 of this gearboxes, from 75-150EUR each.. so probably i will buy one and ask seller to take this gears out and send to me, and he can trash everything else :D
regards
WS
Could you send me a link please. I am interested too or if it is possible pm me for sending you money to buy a pair for me too. Thank you in advance
Could you send me a link please. I am interested too or if it is possible pm me for sending you money to buy a pair for me too. Thank you in advance
You have a PM
regards
w
Steve Webb
15-01-13, 18:23
Be interested to see what the mph/1000rpm of the car was after fitting these gears. Be sure to make motorway cruising a lot more comfortable.
Actually i was thinking a 0.71 ratio in 5th gear but for now i'm sure it will be great. I hope we could buy these gearboxes
I have not read the whole thread but the Fiat Coupe has a 3.1 final drive vs the 3.3 in the Q4. If you wanted a slightly longer set of gears, use the Coupe FD! I would rather have shorter gears. 3.3 or 3.5 even. Its illegal to go faster than 110km/hr on the freeway in Aus.
I have not read the whole thread but the Fiat Coupe has a 3.1 final drive vs the 3.3 in the Q4. If you wanted a slightly longer set of gears, use the Coupe FD! I would rather have shorter gears. 3.3 or 3.5 even. Its illegal to go faster than 110km/hr on the freeway in Aus.
if you want all gear longer like coupe, you need to open whole gearbox and replace final ratio gear on diff, I think it will not fit from coupe becouse coupe is FWD, but you can use it from dedra integrale or deltas, but not EVO models
You also can use the Dedra Box, it fits with no modifications and it has the same 3.1 final drive like Fiat Coupe.
Only problem is the torque distribution of 56% front / 47% rear.
You additionally could change the old dedra main diff. to the main diff from 16V Delta Integrale (my solution, fits without changes as well).
Then you have a 3.1 final drive and the torque distribution of 47% front / 53% rear.
I think the 30/37 gearset is too long, you then would have a very very big gap between 4th and 5th gear?! That's not nice as well!
Much more interesting is Bacciromano solution, 29/25 ratio = 0.862
Then the gap is not as high, it is more driveable...
Juergen
You also can use the Dedra Box, it fits with no modifications and it has the same 3.1 final drive like Fiat Coupe.
Only problem is the torque distribution of 56% front / 47% rear.
You additionally could change the old dedra main diff. to the main diff from 16V Delta Integrale (my solution, fits without changes as well).
Then you have a 3.1 final drive and the torque distribution of 47% front / 53% rear.
I think the 30/37 gearset is too long, you then would have a very very big gap between 4th and 5th gear?! That's not nice as well!
Much more interesting is Bacciromano solution, 29/25 ratio = 0.862
Then the gap is not as high, it is more driveable...
Juergen
I'm also afraid about gap bethween 45h and 5th gear, but I will see when I finish car...
It is all matter of torgue. For a completely stock car 0.81 is to long when change from 4 to 5 gear but if you have a modified engine with a lot of torgue it would be much better specially in trips
It is all matter of torgue. For a completely stock car 0.81 is to long when change from 4 to 5 gear but if you have a modified engine with a lot of torgue it would be much better specially in trips
I planning around 260-300 HP so I think it will be good,time will show...
Two sets of 30/37 gears, scraped from TD gearboxes :)
will have to mount one set to my gearbox in the near future.
Thanks, for the tips.
W
Steve Webb
09-02-13, 14:31
So its possible to make a longer 5th gear using the gearset from the 2.5td gearbox, but is it possible to make a shorter gearbox using the gears from another Alfa gearbox? Say the gearbox from the 155 1.7.
I don't know if these gears can fit to the gear axcel! 2.5TD and our Q4 gearboxe are available to handle "high torgue" and they are enhanced so i am not sure if the gears from a smaller gearbox can fit to our thick gear axcel
peter holst
10-02-13, 13:05
what about the other gears in the TD box - are they the same as the ones in the Q 4 box?
maybe it is possible to make an close ration box using the 2 boxes?
I guess even all gears can fit, it would be a longer ratio. The only i don't know is the ratio of the differental (crown and pinion)
peter holst
11-02-13, 05:53
no good then - need a shorter ratio
gears from 2.5 TD are same like in Q4 except longer diff and longer 5th gear.
some diff ratios:
-2,947 delta HF 8vT 4WD
-3,111 coupe 16vT, dedra 8vT 4WD, all delta, delta II HF
-3,176 dedra 8vt FWD
-3,353 Q4
-3,562 delta II HF HPE 98-99', tempra 4WD
-3,93 dedra II S.W. 16v AT 4WD 94-99'
Steve Webb
17-02-13, 11:19
Created to give the longer 5th gear modification its own thread.
peter holst
18-02-13, 09:34
gears from 2.5 TD are same like in Q4 except longer diff and longer 5th gear.
some diff ratios:
-2,947 delta HF 8vT 4WD
-3,111 coupe 16vT, dedra 8vT 4WD, all delta, delta II HF
-3,176 dedra 8vt FWD
-3,353 Q4
-3,562 delta II HF HPE 98-99', tempra 4WD
-3,93 dedra II S.W. 16v AT 4WD 94-99'
I am not a mecanic - but a psykologist
does that mean that the dedra gears from the 4WD will fit and give me shorter rations?
I am not a mecanic - but a psykologist
does that mean that the dedra gears from the 4WD will fit and give me shorter rations?
I'm not sure about that diff ratios, I've find that on: www.automobile-catalog.com/
seems to me like big diference between dedra and other cars ratio
Alfa Patch
20-02-13, 14:55
Looking forward to hearing the results of this. Ive now driven the car enough to get annoyed with its low cruising speed again.
Unfortunately there are probably more Q4's than turbo diesels in the UK. Finding a 2.5 gearbox will be fun to say the least!
peter holst
24-02-13, 16:11
I have not read the whole thread but the Fiat Coupe has a 3.1 final drive vs the 3.3 in the Q4. If you wanted a slightly longer set of gears, use the Coupe FD! I would rather have shorter gears. 3.3 or 3.5 even. Its illegal to go faster than 110km/hr on the freeway in Aus.
Me too . I have been trying to explain Enrico (scara73.it) what i want but not good enough :(
Can any one tell me what parts i need to have shorter gears (3,4,5)?
Enrico has already in his product a shorter ratio. Crown and pinion for making all gears shorter
http://scara73.it/motore/motor14.html
Look at the second picture
today it was the first ride with my "new" car and i will tell you my opinion about 155 2.5 TD gears. it is a bit tiring at short trips because i need at least 4,5k rpm with 4th gear to change in 5th. i had almost 150 km/h with 4.1k rpm . for a long trip to national roads it is the perfect choice in my opinion
peter holst
27-02-13, 14:23
[QUOTE=Stichl;24527]You also can use the Dedra Box, it fits with no modifications and it has the same 3.1 final drive like Fiat Coupe.
It says a bit later at this tread that the final drive for the dedra is 3,93?
As I read it the dedra has the lowest final drive.
Gear ratio formula:
MPH = RPM/GEAR RATIO x WHEEL DIA/335
wHeel dia in inCHes
gear ratio = ratio gear x ratio diff
(sorry for HIGHER Case letters, on tHis forum my H,C,V do not work in lower Case)
Thanks for that ecuation. I guess wheel diam. Includes the tyre profile too so you mean full wheel cycle
Yes measure thread to thread(front to back)
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