[PigLick]

Just wondering, does BMW have any sort of VVT system? Given my limited knowledge on auto mechanics, it seems like the MINI would be a perfect candidate for such a system, and given the complex computerized systems found ubiquitously throughout the MINI, I'm almost surprised this wasn't included. Perhaps something for the future...or am I just a complete idiot?

PigLick

[myminis]

actually, BMW does have Variable Valve timing, they were doing if BEFORE Honda. I believe it's called VANOS.
Anyway, chrysler, which our engine basically is, does not currently use it

[PigLick]

That's pretty much what I figured. It would be interesting to see what kind of engine BMW would develop for the MINI if they were to take it upon themselves to do so.

PigLick

[chiph]

There's an item in the News section that talks about how BMW is going to partner with Peugeot to build engines for Citroen, Peugeot, and MINI starting in 2007.

Despite most American's opinions of French cars, Peugeot actually builds some very good engines (especially diesels - they invented the common-rail fuel system). Don't know if the engines will use VANOS or the new Double-VANOS (oh please! oh please!), but it would be very nice if they did.

Chip H.

[Pete Hopkins]

I Thought VW were the first to use direct injection diesel engines, not Peugeot? I maybe wrong!

[chiph]

Oops. Got the company wrong - it was Fiat, invented by Rinaldo Rinolfi.

See the announcement of The Economist's Innovation awards here. Here's another article from Autoworld.it translated to English by Google.

I imagine VW was first to market, though.

Chip H.

[zgokart]

[quote]Originally posted by chiph
[b]There's an item in the News section that talks about how BMW is going to partner with Peugeot to build engines for Citroen, Peugeot, and MINI starting in 2007.
Despite most American's opinions of French cars, Peugeot actually builds some very good engines]
______________
You are correct on the above

[daver]

It's rumored that the BMW bosses are not entirely happy with the current (Chrysler) engines, especially regarding the fuel consumption. Therefore they will replace them in 2005. Perhaps along with a revised MINI (or new variants)
Remember it's just a rumor

[NearlyNN]

I'm just now reading a very good book, New MINI by GrahamRobson, which addressed the subject of variable valve timing. The following discussion took place in summer/autumn of 1997 while the Rover Group was still in control of manufacturing development process:

"In the end, the only major feature on which the companies agreed to disagree was that BMW wanted to use variable valve timing technology (and advertise its presence) while Chrysler's engineers did not. Major arguments, discussion papers and presentations solved nothing, and in the end it was a BMW steering committee which backed down, and the proposal was abandoned." .....page 70.

Granted this was five years ago, but it appears that there is strong BMW sentiment in favor of VVT. Would be very surprised if the next incarnation of the MINI and its engine do not include it.

[minimc]

I'm SO glad someone touched on this. ...It’s exactly what the Mini NEEDS. All versions would benefit from improved fuel mileage & performance. The torque curve would be flattened. [b]Drooling[b] Oooh baby!

...Can't believe that BMW gave in to D/C on this. What a gaffe!

[ssimms]

This wasn't BMW giving in to Daimler/Chrysler. Remember when the agreement was struck, it was with Chrysler before Daimler acquired them. And, if I am not too mistaken, the agreement was made because BMW didn't have, in it's shelves, a small 4 cylinder transverse mount engine with a low enough profile to fit under the MINI bonnet. Secondly, Chrysler was rumored to be considering this engine as a replacement for it's non-US Spec cars and the design work had already begun. BMW needed this engine quickly for the MINI and my guess is that they decided that this arrangement would allow for a very quick turn around R&D for the MINI project to be completed on time. (Not to mention the cost savings to BMW)
Now that Daimler has purchased Chrysler, that changes the whole complexion, since BMW and Daimler don't play in the sandbox together. This was probably the final straw that broke the camel's back, to looking for a new engine partner with enough time left on the existing agreement with D/C so that BMW could do it's own R&D and produce a proper powerplant for the MINI about the time a 'next generation' was due based on BMW's typical 7 year life cycle. (lest we forget, BMW has never seemed entirely happy with the engine they received from the Brazilian plant to begin with)
These are my impressions of the events leading to the Puegot/Citreon arrangement and frankly I am looking forward to the result. In fact, I will place my name on a list for a new "Open" convertible with the new motor(2007 model year???) when my Cooper comes in next month.
Sorry for the long diatribe.
Scott

[MRVTEC]

Quote: Originally Posted by myminis

actually, BMW does have Variable Valve timing, they were doing if BEFORE Honda. I believe it's called VANOS.
Anyway, chrysler, which our engine basically is, does not currently use it

You sir are ENTIRELY WRONG

BMW introduced the VANOS system in 1992
HONDA had VTEC IN 1989 three years before BMW

The VANOS system isn't variable valve timing strictly speacking because it is a system to retard or advance the cam timing.
Variable Valve Timing is the system to switch between cam lobes.
Honda has just released this system with VTEC on the iVTEC engines meaning it is at the top of its game and when you say Variable Valve Timing next time you'll know that Honda has gone one better already
PS double VANOS operates on both Intake and Exhaust Cams and wasn't availiable till the new M3 came out and that was about the same time is iVTEC came out which does the same thing (NEW Type R Civc, NEW Type R Integra)

[markjenn]

You're not ENTIIRELY WRONG, but you're being incredibly nitpicky about your terminology.

The term "variable valve timing" is a general one and doesn't require VTEC. Mosf folks would define it as any system in which valve timing is not fixed with respect to the crank position. You get it by a variety of means, including varying cam timing, multiple cam lobes, or even electronic actuation of valves.

The VANOS system is definitely variable valve timing - Toyota has a very simliar system called VVTi which stands for "variable valve timing with intelligence" and it is another system which advances or retarts the camshafts under compter control, similar to VANOS.

- Mark

[SteveS]

The current MINI engine is pretty simple and is very durable. I have not read of any mechanical problems with the engines despite all of the performance mods we discuss. Chrysler has a lengthy history of making durable 4 cylinder engines which are simple to maintain. BMW makes good engines but they are generally very expensive to maintain and are very complicated. I am pleased with the mini engine currently in the car from a mechanical and durability standpoint, with the exception of the lousy mileage, heavy flywheel and crummy ECU programming. Those three things do need attention. And I dread the day I need a clutch since the packaging does not lend itself to economical servicing.

[obehave]

Quote: Originally Posted by SteveS

The current MINI engine is pretty simple and is very durable. I have not read of any mechanical problems with the engines despite all of the performance mods we discuss. Chrysler has a lengthy history of making durable 4 cylinder engines which are simple to maintain. BMW makes good engines but they are generally very expensive to maintain and are very complicated. I am pleased with the mini engine currently in the car from a mechanical and durability standpoint, with the exception of the lousy mileage, heavy flywheel and crummy ECU programming. Those three things do need attention. And I dread the day I need a clutch since the packaging does not lend itself to economical servicing.

Even with all that the problems you mention, and I agree, they are not the engines fault.
Lousy mileage and crummy ECU are basically synonymous and yes I'm hoping my clutch goes in about another year

[Charger_Pete]

Quote: Originally Posted by MRVTEC

The VANOS system isn't variable valve timing strictly speacking because it is a system to retard or advance the cam timing.
Variable Valve Timing is the system to switch between cam lobes.

Without wishing to nit-pick, YOU sir are actually wrong on this point. The system to switch between cam lobes is called CPS - CAM PROFILE SWITCHING. VVT is the correct term for variaing the valve timing - because that is what it does. It phases the camshaft(s) relative to the crankshaft and can give upto about 49 degrees of swing. However, switching cam profiles can only give you a few degrees phase difference.

I suggest getting your facts right before critising other people

[markjenn]

I see a lot of carping out the Mini's gas mileage. I don't get it. What engine/car of comparable size and tuning does significantly better?

- Mark

[Wobert]

This is quite an interesting thread..........

CPS allows you to "run" two cam profiles of varying lift.......this is completely diiferent to varying the timing, which as it has already been mentioned varies the timing of the cam relative to the crank, thus altering the point at which the valve begins to open, and it's duration....ie how long it is open.

Honda's approach to gaining a (relatively for a road engine that's naturally aspirated) high specific output is to use the VTEC system to give the "best of both worlds".

Achieving a high max.power rating, whilst maintaining a degree of driveability by changing to a less severe profile to give the engine some torque. The typical charateristics of the VTEC engine are good max power, but with max torque produced at 5000+ rpm. This makes for a "peaky" engine for road use, as to make moderate progress you need to rev it, as the torque back-up is reduced.

In the MCS's case by supercharging, you gain massively on both power / torque (since there is a direct relation between the two), albeit at the expense of efficiency.

BMW have tuned the engine for a flat torque curve....from memory 80% of max torque is available from 2000-5000 rpm. There is no way you could achieve that from a naturally aspirated engine of equal capacity.

The down side is reduced efficiency due to the need to permanently drive the compressor.....this I believe is the main reason for the poor fuel consumption. An additional reason is fuelling......judging by the colour of the tailpipes on my MCS I would guess that the fuel map gives a surfeit of fuel across most of the rev range....this too would account for the poor fuel consumption. (Charger_Pete your expertise may be required here!)

Finally......whilst the maximum performance MINI is supercharged, I don't see a need for VVT / CPS as it just adds complication / cost for little in return.

In engineering there is a saying "Keep It Simple, Stupid" (KISS)......never has a truer term been used!

Robert

[Charger_Pete]

Quote: Originally Posted by wobert123

The down side is reduced efficiency due to the need to permanently drive the compressor.....this I believe is the main reason for the poor fuel consumption. An additional reason is fuelling......judging by the colour of the tailpipes on my MCS I would guess that the fuel map gives a surfeit of fuel across most of the rev range....this too would account for the poor fuel consumption. (Charger_Pete your expertise may be required here!)

Robert

Some good points made i must say. The parasitic loss of the compressor is, from my experience, around 10% i would estimate (about 16 HP). This does contribute to worse FE but i would suggest the main reason for the poor FE on the MCS is the agressive fuelling map calibrated into the EMS. This was done purely as a component protection strategy. The extra heat generated from supercharging causes the cats to run much hotter. Thus more fuel is required to cool them down. I believe the AFR (Air Fuel Ratio) at WOT is approaching something rediculous like 7:1!!!

Re VVT, i think there is probably little benefit on the MCS engine purely because the Cam timing is probably optimised for the supercharger. I dont know of any supercharged engine with VVT or VCT. I know that Jaguar dont use it on their supercharged engines - one would only end up foring the fresh charge out of the exhaust valve on overlap periods.

Your thoughts Rob?

Pete

[Wobert]

Quote: Originally Posted by Charger_Pete

Robert

Some good points made i must say. The parasitic loss of the compressor is, from my experience, around 10% i would estimate (about 16 HP). This does contribute to worse FE but i would suggest the main reason for the poor FE on the MCS is the agressive fuelling map calibrated into the EMS. This was done purely as a component protection strategy. The extra heat generated from supercharging causes the cats to run much hotter. Thus more fuel is required to cool them down. I believe the AFR (Air Fuel Ratio) at WOT is approaching something rediculous like 7:1!!!

Re VVT, i think there is probably little benefit on the MCS engine purely because the Cam timing is probably optimised for the supercharger. I dont know of any supercharged engine with VVT or VCT. I know that Jaguar dont use it on their supercharged engines - one would only end up foring the fresh charge out of the exhaust valve on overlap periods.

Your thoughts Rob?

Pete

I can concur the comments rever-fuelling......the Lotus V8 had to have secondary injectors positioned in the plenum, as the std ones fitted to the injector manifolds didn't have sufficient flow, so we had to fit two extra injectors (one for each bank of cylinders) into the plenum. This was down to meeting the regs for the US (Calfiornia mainly, so I recall!)

BTW Pete, how's things on the job front?....still @ Jag or have you had your DCM? (Don't Come Monday!) JCB are still looking for engineers, although it's not in your location of choice!

Cheers,

Robert