UK-POLOS.NET - THE VW Polo Forum

EDIT
Quick note (4/9/04)
Though the ratios contained within the sheet seem mostly accurate, i havent the hellmost clue what size tyres i thought i was writing for. Therefore the speeds per thousand rpm are not to be relied upon as they're all 100% wrong.
I will be correcting this and putting a new version of the sheet up at some point in the near future, possibly with a bit where you can enter your own size tyres and it will calc it all precisely






One to stick in the archive on the 0.01% off chance someone ever looks for it (I'm more anticipating very occasional Google whacks)

http://www.geocities.com/tahrey/polos/index.htm with spiffo explanation

or, to be more direct
http://www.geocities.com/tahrey/polos/b ... rsheet.xls for the spreadsheetly enabled
http://www.geocities.com/tahrey/polos/b ... rsheet.htm for them that wants colour and stuff but are spreadsheetly disenfranchised
http://www.geocities.com/tahrey/polos/b ... rsheet.txt for them that have rubbish spreadsheets that cant grok Excel 97, or are just feeling a bit perverse (note: rename from .txt to .csv before loading into program)

I looked for maybe 18 months for this stuff around the web and got heckuva pissed off. Even more so now I find the Yank data i've been kinda relying on as my baseline is waaaaaay off (totally different shafts and distances between). The stuff making up this (hopefully accurate) chart is from two rather unlikely and varied sources (as well as verification from driving my own car and measuring crank-to-wheel revolutions).

What is it? A sheet containing the ratios and speeds per 1000 / max speeds in gear (assuming 6500rpm and 145 R13 tyres) for pretty much any mk2 or 3 polo gearbox you're likely to encounter, aside from diesels (probably )... it may even cover some mk1 and mk4.

not a final thing, but i'm satisfied that most of the work has been covered. only really a tidy up of the thing (and/or rearrange) and addition of serial codes to do, but the core data will be untouched unless I receive any corrections - all submissions of extra or corrected data gratefully recieved... especially those diesels*! (and confirmation on the dodgy-looking G40 diff ratio*, rev limits for GT/G40/diesel... - I only know the carb and Spi 45/55hp engines are reccommended 6300, hardlimited 6500)

"enjoy", if it's any use to you.
(should be of most help to those looking to replace their boxes but mystified by the codes, esp. if doing an engine swap or similar)

-tahrey


edit
* - basically all i'm after for G40 is what any 145 R13-rider's supercharged engine is turning at 70mph in top (and for reference, say... 30mph in 3rd) - if it's a touch over 3000rpm (or about 2300) then it's all good (i just don't trust that 3.333 final drive ratio, it seems FAR too different).
Diesel its a bit more complex, especially as I don't even know if they came with revcounters in mk2 and mk3 guise - they were kind of the poor relation at the time basically max speeds in the first 3 (4?) gears, and where the rev limiter bites if known, along with.... i dunno.... dial-measured speed at idle in top if no counter, or revs at 50 in 5th if you do have one. If I'm lucky i might see one of the existing ratio patterns emerge from the first 3 or 4 gears. Cheersy-bye

The G40 box (ATV) does have a final drive of 3.333, and from memory 70mph in 5th is around 3,000rpm. My old CL box (8P) was roughly 3,400rpm at 70mph in 5th - and my current GT box (AHD) is about 3,800rpm. It's been a while since I drove with the ATV box, and even longer since I drove with the 8P though - so these might not be that accurate!

cheers dude those numbers match beautifully

(and if its 3400 at 70 rather than the 3250 or so i worked out for the 8P then I'm laughing when that box goes on..... it'll run sweet-as. Or was it because you had less clown-car tyres than mine and adjusted for it? )

sheet has been mildly tweaked with some other numbers i picked up btw, just early 80s ones like 3+E, low 4s and early G40. I'm not going to bother with golf and mk4 ones, at least not for now - theres far too bloody many of them!

I was running 165/65 R13 tyres at the time - take it you're still on the standard squareback 145/80 R13s? Now they're scary to drive fast on!

Shortly going to be changing to 185/50 R14 or 195/45 R14 though, as I need larger wheels to clear bigger brakes. And I need bigger brakes for when the G40 goes back in, coz I'm not having ~170bhp without anchors to match...

Oh yeah homeboy, the trip to Alton Towers (hopelessly lost, and trying to catch mates who left Tamworth's maccy D drive thru 10 minutes before I even found the place) was the first rollercoaster thrill ride of the day. Except without the fear that your ankles* or scalp are going to go missing along with your lunch and those three bottles of orange VK.

(* if you're on Nemesis rather than a regular ride...... neither if it's Air - now there's a rush, makes you want to sell the car and buy a powered hang glider)

Originally I had 145/70s on purchase of the car, for (i guess) a slightly more direct feel on twisties (and better acceleration) but louder/slower on the m'way. When I had those replaced cheaply, somehow ended up with 80s.... oh well, tis the way the world works. I was a strapped student and just needed one non-bald, and one non-punctured tyre without caring too much about the details so long as they were the lowest priced ones in the town. £23 each including fitting and balancing IIRC, quite a bargain considering how long they've lasted and the fact I'm still not in a hedge on the outside of some B-road hairpin.

Actually they're not so bad at speed (says he, not having known anything different, nor often velocities beyond the 150kph barrier), goes round motorway corners lovely (boyo), its the city roundabouts that make me brick it far too often - would wider rubber solve that?
These wheels I got from David B are 155/70, put them on soon as I can. I know it's only an extra 2/29ths, but will it have some noticable effect? Seem to be exactly the same circumference as the 145/80s (as, I suspect, the 165/65s are, within a couple % or so, if my maths work right) so thats pretty cool... not any more direct, but not any slower off the line once the slight extra weight is considered (and of course, slightly harder to turn wheel when parking )

Actually unless you adjusted your speedo for the wheels, your road speed might change, but the one indicated on the dial would remain the same. I think mine went from being maybe a half mph "under" actual speed on the 70s to about 1mph over on the 80s. (or worse! - 66 vs 69.5 inches circumference... so if we say actual speed matches indicated on 75s, theoretically at 67.5mph, the 70s would give an indicated speed 1mph under, and the 80s, 2mph over....)

Oh, um, sorry, got those back ter front The 70s would make the car go slower, so the indicated speed would be higher than actual, and vice versa for the 80s. As it is, the best measurement I can get (rubbish ones!) suggests the speedo is registering ~1mph over actual road speed, so maybe it was a whole lot further out before! Like a full 4mph over at 70mph? (or is it out now, under-reading?! i havent been flashed yet..)... which also means 6mph out at 105mph, so the top speed I thought I once got it to may not even have been over the ton not to mention throwing doubt on all those home measured 0-60 times.

(or to stay tentatively with the gearboxy subject, altering a supposed 17.63mph top on (non existant ) 145/75s, to 17.15 on 70s, or 17.96 on 80s.. altering revs at 70 between ~4100, and 3900 quel differénce! ... or with 21.2 on the new box, up to a torque sucking 21.6 (almost putting 70 inside the torque band, and almost pushing 60 out of it!) or down to a slightly friendlier 20.6 (still good for reasonably quiet cruising at 75)... what a change a number on a bit of rubber can make!!! )

The more i ponder these things, the more I think i either need to enlist the help of a friend with a stopwatch, a very long tape measure, and a runway, or blow £20+tax on a rolling road sesh.

Arrgh!

Right, settle my mind and stomach, do you know how tall your tyres are compared to regular 145/80s? My maths say roughly a 67.5 inch rolling circumference, or conveniently right inbetween my two
(and the fresh ones, 67 and 65.5 respectively for the 185 and 195)

((just had a double check in the documentation for the correct tyre sizes, in case everything was worked out for 145/70s rather than 80s.. but, it is stated to use 80s... so why in the heck did the previous owners fit those smaller tyres? They didnt look like boy racers really... Were they using the car to pull a caravan, needing a little extra 1st gear grunt (squeak ), but removed the towhook before selling it?? )

anyone ever come across an SET coded gearbox, serial number 085 301 103? Think the scrappy has given me an entirely wrong box, like off a 1.3 post-94 Golf....

it's going back anyway for various reasons, but the code is bananas, the fittings look plain wrong, and the spring for the clutch release is external (whereas on my 4sp it's internal).... would like to track down it's origins, if by some miracle it's a mk2/mk3 polo original AND wide ratio like i asked them for.
i'd work it out myself, but the little matter of it no longer having any oil inside seems to have seized it, or at least removed lubrication to the point where it's not hand-turnable (... and i've turned a wheel connected through a gearbox to a halted engine before with my hands..)

if it would have been totally gonzo to my needs regardless, thats one more thing to hook with

plus i can stuff it in the database! got another update to upload but think i'll hang on a couple more days til this is sorted out.




EDIT
Quick note (4th sep 2004)
Though the ratios contained within the sheet seem mostly accurate, i havent the hellmost clue what size tyres i thought i was writing for. Therefore the speeds per thousand rpm are not to be relied upon as they're all 100% wrong.
I will be correcting this and putting a new version of the sheet up at some point in the near future, possibly with a bit where you can enter your own size tyres and it will calc it all precisely