pulley size

[Ä‘uro]

What pulley size would y. recomend to buy (smaller one)? 70 or 65 mm ?

[Robin]

65mm is the most common size for upgrading

[Ä‘uro]

But ho does it work on highways? Is rpm to big or not?
Do I hv to do something with my charger or not?

[breadman]

Obviously the charger will spin faster all the time, but if it's in good working order there should be no problems.
On the highway you're probably spending most of your time in 5th gear, so engine rpm will be relatively low - around 3 -3500rpm? This will be no problem for the charger at all.
However, charger life is reduced if you have a smaller pulley fitted, but it is more related to the way you drive than anything. Spend lots of time at very high rpm and the charger won't like it.
Normal day to day driving with the odd blast should be ok.

[Ä‘uro]

Well it's easy for y. to say around 3-3500 rpm. If engine runs on this rpm I will go 80 km/h 
My poblem is gears are not fm G40 but fm Seat Arosa. App speed (traveling) is around 120 km/h nd engine is spinning around 4800 rpm (in 5th gear). Cos of this i'm asking if 65 pulley is to small?!
I know that max pressure is in 5th gear on 6000 rpm but who can drive all the way full trottle?

[breadman]

Ah, so you're not running an ATV box then?
That Seat gearbox must be from a low powered version if the final drive is only giving approx 75 mph @ 4800rpm in 5th! That is a very low final drive, really not suited to the torquey nature of the G40 engine.
I'd be looking at getting a more suitable gearbox first to make the most of the car before fitting a smaller pulley. Unless that is you chose the very low ratio gearbox for some other reason?

[Ä‘uro]

well this car first was mntioned to be car for streetrace or hill racing, noting else, but now it become everyday car. Max speed is 190 km/h at 7000 rpm. People usualy don't expect fm engine 115 hp that goes like 1.8T. I want to change pulley just for fun but alm must hv in mind everyday driving (city driving) but also sometimes highway driving musn't be forgoten.

So, if y're telling me 65mm pulley is fine will put one. Hv in garage original G40 gearbox but when placed engine in car tought this would be better - car will be faster on smaller distance, nd it is. but....when y. don't hv many friends with this engine y. can only make something by your opinion.

[breadman]

Yeah I can understand the reasoning of fitting this gearbox if the car was to be used for hillclimb/sprinting. High speeds are relatively unimportant in these sports.
However, you have to be careful with not having gear ratios that are too short. Short ratios often make the car feel quicker than it actually is. I'd try and fit a gearbox from something with a slightly taller final drive. One with a final drive ratio around half way between the one you currently have and that of a G40 box. I don't think you'd notice the difference in acceleration but cruising would be more comfortable.

[Ä‘uro]

I'm just interesting is standard G40 blows 0.5-0.6 bar wit standard pulley how big presure will be with 65 mm pulley?

[PeteG40]

with a 65mm pulley approx 1-1.1 bar

[Ä‘uro]

but it depends on lader condition. nd if it's upgrade on RS2? 1.3-1.4bar?
Can glader handle this kind of presure? Do I hv to change injectors?

[PeteG40]

no 1 - 1.1 with a very good condition and very well flowed lader. They boost reliably for 20,000 miles with a 65mm pulley

[Ä‘uro]

Do i hv to put bigger injectors (e.g. fm G60) or I can run with standard ones?
I'm asking cos I saw on SLS page they hv computers for smaller pulley or for converzion to G60 or remap for 1.4 bar presure.

if I hv to do that (put bigger injector) I must put new computer map or even better - stand allone comp. correct ?

[PeteG40]

you dont need to use bigger injectors - just a suitable chip.

if you do use bigger injectors then you need a chip mapped to those injectors