motor

Wutputt · 02-09-2005, 02:45 PM

Originally Posted by caneswell

How is this different from BMW's valvetronic? They have been using throttle-less induction for quite a while.

If I understood the official explanation correctly, this uniair system regulates the valve lift for each cylinder individually in order to regulate the intake air resonance interference between the different cylinders, where as BMW's Valvetronic changes the valve lift for all the cylinders together. So all the intake valves have always the same lift (expect with Valvetronic II, which has a built in difference between the two intake valves of each cylinder to improve in-cylinder flow at low and mid-range rpm).

Also the uniair system uses a different valve lift actuation system (hydraulic pressure vs an electric motor turning an eccentric shaft for the Valvetronic) and takes into account some more parameters (for example cylinder individual flow sensors).

caneswell · 02-09-2005, 02:48 PM

Originally Posted by Wutputt

Originally Posted by caneswell

How is this different from BMW's valvetronic? They have been using throttle-less induction for quite a while.

If I understood the official explanation correctly, this uniair system regulates the valve lift for each cylinder individually in order to regulate the intake air resonance interference between the different cylinders, where as BMW's Valvetronic changes the valve lift for all the cylinders together. So all the intake valves have always the same lift (expect with Valvetronic II, which has a built in difference between the two intake valves of each cylinder to improve in-cylinder flow at low and mid-range rpm).

Also the uniair system uses a different valve lift actuation system (hydraulic pressure vs an electric motor turning an eccentric shaft for the Valvetronic) and takes into account some more parameters (for example cylinder individual flow sensors).

I see, thanks.

findleybeast · 02-11-2005, 05:57 PM

If we're talking about a maranello your figures are not that accurate as the 575 has 515hp so the leap is even bigger.

haha yeah I actually found conflicting performance figures. I based mine off what I found at ultimatecarpage.com
if it is 515hp, then its a 115hp jump... :shock:

mv · 02-11-2005, 06:09 PM

Originally Posted by findleybeast

If we're talking about a maranello your figures are not that accurate as the 575 has 515hp so the leap is even bigger.

haha yeah I actually found conflicting performance figures. I based mine off what I found at ultimatecarpage.com
if it is 515hp, then its a 115hp jump... :shock:

But on the other hand you could have been right as the 575 Superamerica actually has those 540hp you claimed.

ZfrkS62 · 02-12-2005, 06:21 PM

looks like evryone is trying to play catch up with BMW

It's going to be awhile before everyone finally does though. I can only imagine what BMW has up their sleeve for the Valvetronic system of the N series Inline 6's on the E90. followed by the N62TU which will more than likely follow in the E65/66 in it's final years of production before the next 7 series.

Aren't technology wars fun

findleybeast · 02-13-2005, 04:26 PM

well the only system BMW has that can compete with this is the one the new M5 has on the V10 with individual butterfly valves for each cylinder. The normal valvetronic doesn't control intake for individual cylinders.

but yeah, tech wars are great. the car industry would still be in the Model T era without them...

caneswell · 02-13-2005, 06:38 PM

Originally Posted by findleybeast

well the only system BMW has that can compete with this is the one the new M5 has on the V10 with individual butterfly valves for each cylinder. The normal valvetronic doesn't control intake for individual cylinders.

but yeah, tech wars are great. the car industry would still be in the Model T era without them...

Nope!

Read this http://www.bmwworld.com/technology/valvetronic.htm

You're getting confused. I have individual throttle valves on my 15 year old bmw!!!

findleybeast · 02-13-2005, 10:10 PM

oops yeah I guess I was mixed up with the double-vanos technology

ops: I think I read some incorrect info recently actually. Thanks for clearing that up. After reading your link I guess that would explain why BMW wouldn't put a great new technology on the new V10 (which DOES have individual throttle bodies per cylinder). I wonder if Fiat's system is effective over 6000rpm?

caneswell · 02-14-2005, 02:42 PM

I think the main drawback to BMWs system is a loss of throttle response. As an electric motor has to move the valves via a worm gear, so it will always be slower than a regualr throttle valve.

Throttle response is a very important part of BMW driving experience, especially on the high performance cars ( The main reason behind them not relying on turbocharging to make power). So this is why you don't see it used on the M cars.

findleybeast · 02-14-2005, 03:40 PM

That's actually one of the qualms I have with BMW's system. Its not just that the response my go down, but that little motor is going to be moving damn fast at higher rpms, and electric motors burn out fairly easily, particularly on heavy workloads. I wonder how reliable the system is, particularly after a lot of miles.