Quick interjection before getting more than about halfway down the thread
1043 4 speeds seem quite happy sitting at 90 (or whatever you can get em up to on full bore). Haven't studied the real long term effects of this, but i've put more than 20k miles on mine so far with probably 10k being merciless blasting, and there doesn't seem to be much in the way of trouble. You can't redline it in 4th after all, not without a VERY VERY big hill, and the VW redline is traditionally quite conservative.
(NEED a quicker car
)
70 will be nothing to one! It'll run at 70mph til the end of time probably, if you keep it serviced, even though it's doing like 4000rpm...
IIRC the 5-speed gearboxes offered for the 1-litre didn't change the top gear much from the 4 speed, if at all, just gave you a closer set of ratios in order to perk up the almost non-existant acceleration... Some might have got a more GT-like box (eg Metz's saloon), which is a *little* bit better for cruising (say 10% tops) but not quite as good for speed in either 4th or 5th. Was hoping he had something like a regular 4 speed with a motorway 5th on it, but the results are inconclusive so far.
If you really want motorway laziness with some capability left, a 1.3 non-GT 5 speed is where it's at
... the fuel consumption will actually be better (lower rpms and not having the throttle kicked wide open anywhere near so often - amazing what 10hp reserve power can do), there's no change in the tax band, and the extra insurance (maybe a couple hundred quid a year if you're already being buttraped by the brokers) is probably well worth it.
EDIT: Yep, they're designed to cope with driving situations up to and including going all the way across Deutschland in one day on the unrestricted motorways. Any speed that you can eke it up to should be fine unless you regularly go over Shap...
An 8P may be a decent swap for the motorway but might actually prove to be *too* long. As it comes off a 1.3, the overall gearing (based on the differential) is another 5% or so higher - so all gears from 1 thru to 4 go upwards (ever so slightly more sluggish acceleration and an mph or so off the top speed), and 5th will be crazy, like 22.3mph/1000 - not even doing 3200rpm at 70mph, which is close to the limit of what a 1-litre's power output can support. It'll still do it fine, and you could probably run up to about 80 on the flat, but you'd be changing down quite a lot... (you would get
awesome economy at 50-60 however!)
I'm thinking along Groovy's lines - some kind of hybrid would be grand. But that would be even more complicated than swapping the box out. He's been brave enough to do that.... I wouldn't be. I almost did it with my own polo, waybackwhen - £100 for the box, and estimated at another £100 for the fitting, but it all went t**s up ('box arrived badly damaged and the code was wrong, too - it literally took months for me to scrape back the hard-earned from the robbing b*stards and it spoiled me on the idea).
Shouldn't be too difficult to make it (or a brilliant 6-speed - apparently the 5 speeds have the requisite bits in the right places) if you somehow get hold of an 8P and a 1-litre 5speed, and have the knowledge/tools/cojones to open up and partially strip out 2 gearboxes... either putting the differential from yours into the 8P (it would have to be that way round as the 4 speed casing is minimalistically small!), or, the 8P 5th (complete with synchro etc) into the 1-litre 5-speed, as the 6th gear.
However, if you're careful, you can get 45-50mpg out of the 4-speed with normal but relaxed driving (i still get 35+ with the pedal buried), and all you have to really deal with is the high pitched boomy noise from the engine - for which I reccommend a half decent stereo as a viable and cost effective alternative to a gearbox swap.
But then you get what you pay for and all I'll say is that the difference it has made over what the previous owner put in (Magatec on the recepts) is amazing the engines seams to run so much better and soother.
