Variable SC Pulley

[verylost]

I have been running this idea through my head for a few days now and was wondering if it has been done and if so, how was it done.

I remember reading a year or two ago about Audi's (not 100% sure if Audi) solution for a sequential transmission using a variable diameter gear rather than different individual gears.

Now is this possible for a supercharger application? I think on paper it would work great. However, I haven't been able to figure out how to build something strong enough to handle the stress.

 

[Lextreme II]

Doesnt work. Not SC application. Tranny is completely different. If it is possible, Vortech or ATI should of have this product already. One of many friend recently did an ATI P1SC pulley with a clutch. It worked ok, but at high rpm it still slip. We are currently designing a two stage pulley for supercharging application. It has two grooves or pullies. One is stock 5.25" and other will be an 8"

Stock 5.25" pulley will be the inner one and the 8" will be the outter pulley. 8" crank pulley will make crazy boost. Twin Screw supercharger with 8" can make up in the low 20s psi.

 

[Zuffen]

In the late '70's DAF (Dutch car maker) had a transmission based on differing pulley ratios. The pulleys operated as a sliding cone. as one pulley closed up the other opened up giving the gear change. The set up was highly successful and many thoousnads of DAF's grace European roads.

Lots of ride on lawn mowers use a similar system for their transmissions.

Whilst it's possible to make it work it is a cumbersome sytem and would look butt ugly.

Personally I don't think it would be worth the effort.

 

[verylost]

Doesnt work. Not SC application. Tranny is completely different. If it is possible, Vortech or ATI should of have this product already. One of many friend recently did an ATI P1SC pulley with a clutch. It worked ok, but at high rpm it still slip. We are currently designing a two stage pulley for supercharging application. It has two grooves or pullies. One is stock 5.25" and other will be an 8"

Stock 5.25" pulley will be the inner one and the 8" will be the outter pulley. 8" crank pulley will make crazy boost. Twin Screw supercharger with 8" can make up in the low 20s psi.

I don't think you quite understood my explanation.

Rather than a system where you change gears like a tranny, the diameter of the pully itself would change in diamter/size. And to accomodate the change in belt length, a dynamic belt tensioner would be needed. A clutch wouldn't be needed. It wouldn't work like a conventional transmission. I am basically suggesting taking out all the gears and leaving one gear that can change in size.

I think it's pretty complicated. I haven't figured out how to make the pulley itself structurally sound let alone worry about the belt tension assembly.

The 5'' to 8'' pulley idea is a more simple and efficient design but a variable diamter pulley would give you many more options and you'd be have more control over tuning.

In the late '70's DAF (Dutch car maker) had a transmission based on differing pulley ratios. The pulleys operated as a sliding cone. as one pulley closed up the other opened up giving the gear change. The set up was highly successful and many thoousnads of DAF's grace European roads.

Lots of ride on lawn mowers use a similar system for their transmissions.

Whilst it's possible to make it work it is a cumbersome sytem and would look butt ugly.

Personally I don't think it would be worth the effort.

It probably isn't worth the effort and the cost for R&D is probably rediculous too.

What mechanism do riding lawnmowers use to change the size of the pulley? Internal springs? Motors? Hydraulics?

 

[Lextreme II]

The variable pulley will be very complex and with other accessory parts. If it is possible, the pulley have to withstand massive torque and tension. As far as application to 1UZFE, this would not work. You can not go any larger then the stock 5.25". You can go smaller, but why? The easiest and most real solution would be making a two stage pulley. One is dedicated for the engine and one is dedicated for the supercharger.
Here is a picture of a BBK pulley

Here is a link of Clutch Pulley

 

[quadcam boat]

Vary-speed pulleys are very common on farm equipment, however they are bulky for the amount of power they transmit. I have them on my grain harvestor for example. They work by having a pulley that are is split in the middle and a spring on the outside that pushes the 2 halves of the pulley together. They then have an adjustable tentioner which is either manually adjusted with a screw or an electric ram. When the belt tention is low, the spring holds the 2 halves of the pulley together and the belt runs on the on a large diameter on the pulley. THis effectivel makes a large diametre pulley.
When you want to change the ratio, you put more tentsion on the belt and the 2 pulley halves are driven apart by the force ( the spring pushing the 2 pulley halves togehter starts to compress.) The belt then effectivly runs further inside the pulley and on a small diameter which therefore changes the ratio.

I think these setups would be impracticle for a supercharger because they only work for v-belts and are slow to change ratio and bulky for the power they transmit.

A better idea would be to make a infinity speed transmission, which is now becoming popular on farm tractors.
This is how I think they work! Effectively this is a planetry gearbox which has a hydrailic motor which drives the outside of the planetry. By increasing or decreasing the speed of the hydraulic motor, the ratio of the planerery is infiniatly variable. I imagine the motor could even range from reverse to dead still through to forward to get a huge variation in ratio.
Have a look on John Deer tractor site for more info.
You may be able to custom build one out of a planetory gear set out od a small auto transmission and use an electric motor to drive the outside of the planetery instead of an hydraulic one, or use the hydraulic fan pump off the lexus to drive a hydraulic motor.
Big job though I'd love to see someone do it!

 

[toyotav8boat]

pulley

honda made a 4 wheel buggy called the 'oddessy' it had variable pulleys on it
they are operated by fly weights
it has 2 split v belt pulleys 1 small and 1 large (in the stopped possition) the small on the engine and large on the rear axle
when the engine is revved the fly weights push the slit pulley on the engine in,(inceasing its dia) which in turn takes up the slack in the belt and starts to drive through the rear pulley as it picks up speed the rear pulley opens up thus reducing the dia and the front pulley closes thus increasing the dia(whilst keeping belt tension) which makes it go even faster until each pulley has opened and closed fully this is its top speed
this is a very effective system ,no gears,no clutch, variable speed
i had one when i was a kid , it gave no trouble
but to use it as sc drive system i dont think it would work it is very bulky and to drive a sc that is draging about 80hp the v belt would slip

 

[Pro]

all new VMoto scooters have the same "variable" pulley that operates via centrifugal force on the side of the crankshaft itself to give it's sh1tty little short stroke 50cc engine enough guts to get it off the line and up to 65kph.

these things are comparitive in size to most harmonic balancers.

you could easily set one of these on the front of your crank pulley and gear it to run a supercharger. instead of the pulley changing size on the s/c, the engine pulley would.

you'd need a "generous" tensioner though - but i could definitely be done.

hmmm....

 

[toyotav8boat]

why bother it would cost $$$$

put that money into a set of low comp pistons and a smaller pulley on your sc

 

[Pro]

yeah you could do that too i guess!

but if people didn't try something different, we wouldn't have EFI for example.

i'd like to try it.