UK-POLOS.NET - THE VW Polo Forum

OK. If a 5 speed box was bolted in place of my 4, what would be the effect:

a/ Bottom 4 speeds the same, with a fairly high 5th
b/ Bottom 4 squished down by some %, with a higher 5th than original 4th but not as much?
c/ combination of the above.

Had assumed that b/ would be the most likely (seeing some numbers on an american site), but after seeing that more recent euro polos have a gearbox that ratios out to basically the same as my 4 with a 5th that gives around 22mph/1000, not so sure.

Even on a 1L, 22/1000 would be nice ... it'll still do 80 in that gear, by my reckoning.

check out this link, i am asking the same thing about the gearbox's!
hope this is of some help!
http://www.tigerstyle.co.uk/poloforum/v ... php?t=1359

all depends on the box but remember that your going to need more mid-range torque for a longer 5th gear otherwise you might end up with worse economy as your foot is further down etc etc

Well seeing as a car is supposedly at it's most effiecient when the throttle's wide open (more easy filling of cylinder, greater compression, less waste to friction per hp output - it's only aerodynamics that suck the power), and also when it's making most torque (so i'm told, no scientific evidence), i'd also like to add an overdrive gear of 24-25mph/1000... the old girl may only squeeze out 45hp, but there's a very good torque spread. Could then sit in the low to mid 70s, foot to the floor, getting about 3000rpm and having very good economy and low noise.

...having to change down to 5th or 4th at the merest whiff of a hill though

It's got enough for a 22/1000, or so my maths say. At the end of the day I'll settle for anything that lets me do 70-75mph without cracking >3600rpm (where, according to existing maths, it starts to get noisy when under a greater load i.e. floored). So even 20 or 21 would be alright. Right now my best guess is i have about 17.5mph/1000, which is just *silly*. It's doing 4000 (~40hp, enough for 80-85mph) by the time it sees 70... Even 4th in my mum's rover is higher than that, and it's a 5 speed..


>>> the wide throttle = better economy thing is supposedly why a smaller engine is more efficient at a certain speed than a bigger one... the bigger one will have less filling of cylinders... and also why 5th can help - brings engine closer to max torque. possibly why it's high on some polos - relatively high-end torque, and 5th gives you it around where your likely motorway cruise speed will be in such a car, 75-85.