[juan37]

When I do gear changes according to the computer, to save fuel, I have no problems.

But when I need more acceleration, and I bring the engine up to 4000 rpm to change the gear, releasing the accelerator in time to change up the speed like from the first to the second gear, the engine was "slow to slowdown" therevolutions, and if I release the clutch fast, and don't give it time to lower the engine revolutions, a heavy pull occurs on the car.

This is normal?

I experienced the same problem, with older cars, like Citröen 2 or 3 CV.

I asked a mechanic friend, if you could change ECU programming, to get a "faster slowdown", but it said was not possible. I will ask this at the VW official service.

They are any way to reduce faster the enginerevolutions before releasing the clutch?

Thanks!

 

[Privatedoc]

The relative lightness of the flywheel in such a small engine is probably why it holds its revs slightly longer than a bigger engine....compression ratio has a bit to do with it too...for example, engine braking in the up is not exactly huge compared to older, heavier, perhaps even 4 cyl 1000 cc lumps

(flame suit on.....Its human mechanics I know about, engines are just a hobby!

)

 

[juan37]

About "lightness of the flywheel", as I know in all internal combustion engines, for less numbers of cylinders, is more heavier the flywheel.

As I mentioned, I observed this problem in 2 cylinders engines, like the Citröen 3 CV.

In my previous vehicles, the las 2 has Diesel engines, the last was a Volkswagen with the 1.9 aspirated engine with indirect injection (I got a similar mileage than the UP with them), and the previous, was a argentine pickup that I completely rebuilded:
https://www.youtube.com/watch?v=BT6Kfl_nj84

I repainted it, and this was the look when I selled it at the begin of this year:
https://www.youtube.com/watch?v=PovfwxwtAY8

In this pickup the last gearbox I placed in them, was a Peugeot BA10/5, and the Diesel engine Peugeot XD2 (2.3 liters) the same than a Leyland version, but it was a little retouched, with the head cylinder of the 2.5 version, which has valves and larger passages, like the admission and exhaust, and corrected injection for more power. The injection pump is licensed by Lucas. With this engine, I hatte a similar problem than the UP but it was slower to increase or decrease the RPM. I went to a injection workshop, and they modified a external regulation of the injection pump, and from there, I could make the gear changes faster, and the engine had a faster response.

In the case of UP, with a computed injection, I think that somehow we can change it too.

Thanks, and Best Regards,

Juan

 

[Privatedoc]

Thanks...I'll stick to internal organs rather than internal combustion engines!

 

[Hambert]

Yeah, the flywheel is in essence a "inertia accumulator", the bigger it's mass, the harder to accelerate or slow down.

I've also noticed the lack of engine braking compared to my old 4 cylinder car with an engine from the 80s. I would say its due to (possibly) a bigger flywheel as said above, a lacking cylinder, reduced friction parts, etc. Remember its an eco-friendly engine, and I'm sure the engineers who designed it removed as much friction and unnecessary counter-forces as possible. All the forces slowing down the car when engine braking are also the ones that reduce efficiency in some way (except compression ratio of course).

So Juan, you can be sure your engine has no problems at all, is just the way it behaves (as I noticed it too). There's no way of slowing down the engine quicker between gear changes using only a ECU reprogramming, it's an engine characteristic by itself.

That is how I see it, but I could be wrong! Please correct me if necessary.

Cheers!

 

[Privatedoc]

WOW I'm learning loads.... keep the posts coming folks

 

[smargh]

I had an old 2002 Swift (3cyl 993cc) before my Citigo and it has taken me a very long time to get used to how long it takes the engine to slow down between gear changes when it goes above 2000RPM.

Nowadays I try to change gear at around 2000RPM, so by the time I raise the clutch pedal it's almost at idle and is ready for the next gear without any RPM changes.

If I change above 2000rpm, for example when accelerating up a hill, then I just have to accept that it's impossible to match RPM during gear changes - it always jumps down a few hundred at least.



Edited by: smargh

 

[Bossphillip]

Hi you make interesting read for what I can make out
You are use to driving Diesel engines. You will get use to
Driving the up after a thousand miles or so.if not
I suggest you go back to driving diesel cars and
Play around as you say. Regards phill,

 

[juan37]

Nice joke!

 

[juan37]

What You know about the automatic version of the UP with the gearbox SQ100?
If it's complicated with a manual gearbox, to get a fine gear change with the engine over 4000 RPM, with the robotized version, itś worst. Or the robotized SQ100 make the gear chages at 2500 RPM?

As I know the SQ100, it's the same MQ100, but with the clutch and gear changes robotized. It's right?

The guys from TopGear speak very well of manual version:
http://www.topgear.com/uk/volkswagen/up/verdict#

But, not so good of the "automatic" version:
http://www.topgear.com/uk/volkswagen/up/road-test/driven

 

[Privatedoc]

Remember the old lupo3L ...? wonder what an up with a small diesel would be like ??....100mpg???? could be good!

 

[juan37]

The UP! is a derivative of the L-UP-O, from which uses the 2 central characters.

The hybrid version of the UP! will use a 800 cm3 TDI engine, combined with the electric motor of the e-UP.

It will give 100 kilometers with 1,1 liter of diesel.

 

[juan37]

Finally, "I got the feel" of my UP!

This afternoon at the exit of a toll in the motorway, to overcome another car, I made the gears changes from the first to the fifth gear quickly and without heavy pulls, and with the necessary torque, but without seeing the tachometer, only hearing the sound of the engine.
I remembered today the first 10 days I hatte the UP, I had a ear problem (a plug of wax), and this, combined with the little tachometer, and the "slow to slowdow" effect of the engine, impeded a good engine management.

Now, after 25 days using the UP, and about 2300 kilometers (1437 miles), "I got the feel" of my UP!