Does anyone have any info on what I need to do to have longer 4th and 5th gears (or just 5th) in my ATV box? Not looking to change final drive as I've heard of the 4th 5th mod being possible without changing this and want the same lowdown pull in 1-3. I would like to do this when I fit my diff - also can anyone point me in the right direction for uprated bearing cases for a stronger box and where to get seals, or anyone that would do all of the aforementioned? Thanks
ATV box has a ratio 0,851. If you need longer 5th gear just put the gear from 8P, AEB or AYZ box (ratio 0,740).
Sounds good, I saw someone on here quote that they changed their 5th and dropped their RPM from 3100 at 70mph to 2750.. Just wondering if this would be the gear that did that or if anyone has any idea where my RPM would be at 70 if I did this.
Does anyone have any info on a gearbox from the 1W / Seat Terra engine at all - the vehicle was a 1390cc diesel. With the torque produced by a diesel engine and with it being geared for a larger engine would it be any stronger? :-\
Maybe a mix of ATV / 8P and the 1W box gears'd work out ok? A longer 3rd and fifth?
- Jimmy
Here is data for almost all Polo gearboxes, with a help of a gear/speed calculator (that is easy to find online) you can check what is the impact on speed.
(http://i1119.photobucket.com/albums/k622/PR23M3K/przelozeniaskrzynPOLO_zpse1ef7e3a.jpg) (http://s1119.photobucket.com/user/PR23M3K/media/przelozeniaskrzynPOLO_zpse1ef7e3a.jpg.html)
Seat terra came with a cem box, no stronger than others because its a late 1 litre polo box
Quote from: PR23M3K on September 13, 2013, 08:08:38 PM
Here is data for almost all Polo gearboxes, with a help of a gear/speed calculator (that is easy to find online) you can check what is the impact on speed.
(http://i1119.photobucket.com/albums/k622/PR23M3K/przelozeniaskrzynPOLO_zpse1ef7e3a.jpg) (http://s1119.photobucket.com/user/PR23M3K/media/przelozeniaskrzynPOLO_zpse1ef7e3a.jpg.html)
Excellent info.. very clear, I'll lose 409RPM at 70mph and at 6700RPM I get a road speed of 172mph instead of 150. I'm currently swallowing 5th gear with ease so will be interesting if the aerodynamics will let it go that far hehe ;D
172mph.... wow!
not that this is relevant or helpful, but the other day i was driving a new bmw 120d and at 70mph the revs sit at 1850rpm... lol
thought it was interesting haha
Quote from: z3i on September 14, 2013, 04:41:49 PM
172mph.... wow!
not that this is relevant or helpful, but the other day i was driving a new bmw 120d and at 70mph the revs sit at 1850rpm... lol
thought it was interesting haha
I run a mk6 Golf 2.0 TDI GT and it's at 1800rpm at 80mph, you get to 140 (on a good day) and ifirc it's still only at around 3200rpm but it won't pull any more.. Maybe if I shape the front like a knife blade it will do 250mph lol.. I wish I could make my Polo a 6 speed :)
I will be popping an 8p 5th into my atv box. Make the A road driving a tad more easy going.
Where would I best source such a gear?
Quote from: physicsfool on September 15, 2013, 11:58:01 AM
I will be popping an 8p 5th into my atv box. Make the A road driving a tad more easy going.
Where would I best source such a gear?
I'll second that question - I fancy trying the 8p 5th too, just hope there's not too much of a gap from 4th, at least you can change 5th gear with the gearbox fitted if you don't like it.
Thought about this and had the same thoughts as above. if you try this martin post your results as im sure many people would be interested
Ay lad, you had a mosey at the state of my diff! Need to sort that before I refit the box
Quote from: physicsfool on September 15, 2013, 08:28:57 PM
Ay lad, you had a mosey at the state of my diff! Need to sort that before I refit the box
is it bad? lol did you ever see mine? looked obliterated. took it too a specialist and they said, its normal, just fit some genuine cv seals. so i did, and it worked! :D
might be worth taking yours to a gearbox specialist just to check tolerances?
In my gearbox it is believed to have a longer 5th and supposed to be at 2750rpm at 70 but I haven't tested it because I haven't had the gearbox fitted to my car yet haha!
Do you know the ratio of your 5th gear? Are all the others standard. And who built the box. Keen to speak to a gearbox guru on the matter
Quote from: vee-dub90 on September 17, 2013, 11:29:50 AM
In my gearbox it is believed to have a longer 5th and supposed to be at 2750rpm at 70 but I haven't tested it because I haven't had the gearbox fitted to my car yet haha!
Was yours the one that was on here for sale a few months ago with the gripper LSD? I fancied that one but didn't fancy the gripper... I should have bought it and sold the diff. Ended up buying an ATB now so should be good if I get the 8p 5th. Let's know how big a gap you got from 4-5th, if you get your box in before I do. Hope it's not like 4th-6th ???
Gap is like 4th to sixth, no good for performance only cruising.
Quote from: Nick_S on September 17, 2013, 07:42:26 PM
Gap is like 4th to sixth, no good for performance only cruising.
ah dam, that sucks. i would rather put up with slightly higher revs
I need a proper cruising gear. Will get it done and follow up
Yeah mine has a gripper fitted, still haven't fitted it and Im not sure on who built it but it will be having a rebuild before its on the car
Well when you do, would you post the ratio/part number of the 5th. Cheers pal
Somebody just come up with a 6 speed box mod and make us all happy! When I win the lotto I will spend a lotto getting a 6 speed box in there somehow 8)
Quote from: physicsfool on September 17, 2013, 09:49:32 PM
I need a proper cruising gear. Will get it done and follow up
This will be good
Quote from: Nick_S on September 17, 2013, 07:42:26 PM
Gap is like 4th to sixth, no good for performance only cruising.
I wonder if when I put my forged rods in and take my RPM to 8k (head flow/inlet temps pending) if (I don't like quoting my current dyno result - 2??hp due to scepticism) would make a low revving 5th gear pull?? - Like mine eats 5th almost as fast as 4th right now so I may benefit... Decisions.. decisions..
what 5 gear are u thinking off? a 8p box gear? so ur saying u will get ur g over 150 mph?
150 is plenty for me in a polo lol
im thinking of getting my casing machined out and fitting bigger bearings to the diff.
Worth having a quick read through this thread.
My problem is that I am running a GT box so I spend 30 miles a day running 60mph @3200rpm!
http://www.polog40.co.uk/forum/index.php?topic=4733.15
Quote from: RyanC on September 17, 2013, 10:43:38 PM
what 5 gear are u thinking off? a 8p box gear? so ur saying u will get ur g over 150 mph?
150 is plenty for me in a polo lol
im thinking of getting my casing machined out and fitting bigger bearings to the diff.
I have had it to 150mph and it was pretty damn close to limiting and was almost at 7000rpm on 13" wheels, it does have a lot of blowby on no3 cylinder which could have been caused by the duff injector making it run lean and as such I was terrified having it in the red as long as I did as I have forged pistons which I didn't want to burn before I do the rebuild with new rods so I backed off. Thing is the two times I've took it this far it has gotten there with stupid ease and if a 6th gear was there, it would pull it. I used http://www.endtuning.com/gearratios.html to work out the road speed if using the ratios on the earlier posted chart, obviously speedo error will need to be taken into account. Not using the 8p gearbox no, using the ATV with the the 5th gear from an 8p, if you use the chart to fill out the gear ratio conversion you will get a road speed figure.. Don't know where to stop! Bigger bearings, metal casings, shot peened gears, ££££'s, I think I may just stick the diff and the 8p 5th into the ATV and hope for the best from the rest of my gubbins.
Quote from: physicsfool on September 17, 2013, 05:38:48 PM
Do you know the ratio of your 5th gear? Are all the others standard. And who built the box. Keen to speak to a gearbox guru on the matter
Sounds like the 0.740 ratio 5th from the 8P box. If you use http://www.endtuning.com/gearratios.html and fit your car with 175/60/13 standard wheels/tyres and stick the 0.740 ratio 8P 5th into an ATV box with a 3.333 final drive ratio the engine will be doing 2728RPM at 70 mph. I'd say 2728rpm will look pretty damn close to 2750rpm when looking at a G40 rev counter hence I think it's this gear. Go to 14" wheels with the same sidewall and your revs will drop to 2606RPM at 70mph and so forth.
When u hit 150 what were u running turbo or a charger? Will be interesting to see what the 8p 5gear will do
Running turbo, charger used to die a death after 125, you'd be extremely lucky to get it to 140 down a big hill with the charger, the load they create must be immense this far round the revs, turbo just keeps pumping ferociously til the end.