Scalable transmission for a Car?

[ndee]

I asked at HT but I think here are more Car enthusiats

OK, I don't know if that's the right word(scalable transmission), but uhm, why isn't there a transmission, which keeps the engine always at 5000rpm, or just the rpms you want? So you could select something like "power driving" which keeps the rpms i the 5000s or "easy driving" which keeps the rpms at 2000

I have no clue about that, but I'm just wondering.

 

[phatcow]

theres the belt driven transmissions found in the Honda Civic HX (i think its called the HVT transmission) that keeps the car at a constant RPM, but changes the gearing ratios of the transmission on the fly.

 

[ndee]

So if you actually have a very strong motor, that car should kick everything else's bu**, no? I mean, if you can always drive at the max. power of a Porsche Turbo and you don't have to change gears, no one actually can compete. Why are there not more cars with such a transmission?

 

[thedarkwolf]

I think he means CVT(constant velocity transmission). Saturn also has one available.

Well Saturn use to have a neat movie thing that showed how it worked on the page but I can't find it now. Oh and they call theirs a VTi transmission.

 

[ndee]

Why don't they built high-performance car with such engines?

 

[Ladies Man]

right now they suck so they aren't being put with powerful cars
in the future though it's something i look forward to

it will still be a cold day in hell though when i give up a manual transmission

 

[Nefrodite]

this was in ht forum a while back. current systems can't take powerful engines, but are useful for saving gas.

 

Continuous Variable Transmission.

C.V.T.


They are not used with performance vehicles because of thier limited torque handling capabilities not to mention thier long time durability problems.

 

[StageLeft]

My mother had one in her early 90's subaru Justy. That transmission was a piece of sh*t. My brother and I through out teenage abuse had the thing ruined after 40,000 miles.

Some of the newer Audis have upgraded CVTs. Not only are CVTs (when done properly) able to give better gas performance than a manual, but are also a tiny bit faster. Kinda sucks cause now we can't make fun of people who buy autos

 

[ndee]

<< My mother had one in her early 90's subaru Justy. That transmission was a piece of sh*t. My brother and I through out teenage abuse had the thing ruined after 40,000 miles. >>


Stupid question but uhm, how can you ruin the transmission if you don't have to .... (what's the proper word in english)....... change gear?

 

[audiophan]

<< I think he means CVT(constant velocity transmission). Saturn also has one available.

Well Saturn use to have a neat movie thing that showed how it worked on the page but I can't find it now. Oh and they call theirs a VTi transmission. >>



saw one at the auto show. instead of gears there is a belt that slides down a cone. the fat end would be 1st gear and the skinney would be the last gear

 

[Scootin159]

the biggest problems for a CVT is that they can't handle much torque (the belt/chain will slip). Also they haven't proven to be reliable enough yet. F1-style transmissions seem to be more promising than a CVT anyways considering that lost time during shifts is essentially 0 and their reliability is proven in their manual-transimssion base.

 

[freebee]

I believe Audi now has a CVT with a metal chain that will handle a higher powered engine. These might only be for the A4's now..but would likely see work in the other models later on.

 

[Zenmervolt]

CVT is Continuously Variable Transmission (not constant velocity, that would be a CV Joint). The problem currently with a CVT is that it is driven off of a torque converter, which necessarily loses some power. Also, CVT's are notorious for having poor ability to transfer torque (which is the main ingredient for acceleration) to the drive wheels. A CVT that did not need a torque converter and could handle high amounts of torque would theoretically yield the best performance and economy.

ZV

 

[MajesticMoose]

<< Stupid question but uhm, how can you ruin the transmission if you don't have to .... (what's the proper word in english)....... change gear? >>



The more moving parts a thing, generally the easier it is to break. YOU don't have to change gear ratios, but if you want to hold the engine at a constant rpm, something has to change the ratio or you will always go the same speed.

m00se

 

[thedarkwolf]

"CVT is Continuously Variable Transmission"

hehe give me a break it was 7:30 in the morning I hadn't been to sleep yet.

 

[ndee]

<<

<< Stupid question but uhm, how can you ruin the transmission if you don't have to .... (what's the proper word in english)....... change gear? >>



The more moving parts a thing, generally the easier it is to break. YOU don't have to change gear ratios, but if you want to hold the engine at a constant rpm, something has to change the ratio or you will always go the same speed.

m00se >>


I meant that you have to change the gear _manually_, like with a stick.

 

[Scootin159]

<<

<<

<< Stupid question but uhm, how can you ruin the transmission if you don't have to .... (what's the proper word in english)....... change gear? >>



The more moving parts a thing, generally the easier it is to break. YOU don't have to change gear ratios, but if you want to hold the engine at a constant rpm, something has to change the ratio or you will always go the same speed.

m00se >>


I meant that you have to change the gear _manually_, like with a stick. >>



And he meant that just hitting the gas hard is enough to ruin the transmission.

 

[puffpio]

Another thing that keeps CVT's from behaving the way you described is that when car companies do market testing to see what the public like, the focus groups and such say thta they don't like this idea (they like the feel of having gears of the engine having gears and moving through the rpm band). So the computers that control current CVT's have predefined gear ratios that they set the CVT chain or belt to. Suxors