aquasurf said:

Thanks for putting the link in. As a new member with less than 5 posts I was not allowed to do it.

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Welcome to the forum!
Sorry, should've said this before.

What you say may be correct, but I'm in my mid 60s and have been driving cars since passing my driving test in 1971.

As far as I'm concerned, our 2011 500TA drives perfectly and the revs don't hang any more than my first car did - a 1968 848cc Mk2 Mini Van. I've had maybe 20 or more cars since then (I could count/list them) and other than performance/economy differences, our 500TA is no different to any of them.

I'll continue to experiment - because I like getting to the bottom of "problems" - and will report back to this thread if I find anything different to what I've said.

Regards,
Mick.

Can/ could your module be made to work in reverse as well? Many new cars also have programmed in delay when accelerating off throttle.

UFI said:

Can/ could your module be made to work in reverse as well? ...

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I know what you mean but, sadly, the answer is no. QREVS module was designed just for one function: to eliminate the slow drop of revs when upshifting gears.

Achieving the opposite function is from the technical point of view very difficult. You cannot easily remove a delay until the moment you detect it and by then it is too late to do anything about it.

Mick F said:

As far as I'm concerned, our 2011 500TA drives perfectly and the revs don't hang any more than my first car did - a 1968 848cc Mk2 Mini Van. I've had maybe 20 or more cars since then (I could count/list them) and other than performance/economy differences, our 500TA is no different to any of them.

I'll continue to experiment - because I like getting to the bottom of "problems" - and will report back to this thread if I find anything different to what I've said.

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aquasurf said:

One possibility you do not experience any rev hang is that you learned to drive to avoid it by backing off throttle about 1 or 2 seconds before depressing the clutch pedal when upshifting. Other possibility is that you avoid revving your engine high before upshifting. Or you are just lucky and your car does not have it .

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I've tried and tried and tried.

I've revved, I've taken it easy, I've changed gear quickly or slowly, instantly or delayed, and at no time does any "rev hang" upset my driving in the slightest.

I can boot it and change late, I can shove the gears down a cog or two, and I can generally abuse ............... or take it gentle ............ and at no time NEVER has there been a problem.

Basically, I ain't got a clue what you're getting at.

Regards,
Mick.

aquasurf said:

One possibility you do not experience any rev hang is that you learned to drive to avoid it by backing off throttle about 1 or 2 seconds before depressing the clutch pedal when upshifting.

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One or two seconds??? If waiting that long would be necessary, then every 500 driver would complain.

I've tried everything too, does it all the time

typecastboy said:

I've tried everything too, does it all the time

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I'm not saying it doesn't do it.
I couldn't care less if it does or it doesn't.
I'm saying that whatever it does, it doesn't upset my driving at all ...... no matter how I drive.

Therefore, does it upset your driving?
Are YOU affected by it?
If so, how does it affect you?

Thanks,
Mick.

Not that we've noticed(original question), but, I have noticed that there is a very small delay from taking my foot off the accelerator and the car starting to slow down whilst in gear( as in, ECU- oh you want to slow down best shut off the fuel and does so), compared to our past/present other cars.

John202020 said:

......... I have noticed that there is a very small delay from taking my foot off the accelerator and the car starting to slow down whilst in gear ....................... compared to our past/present other cars.

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Hi John,
Can you quantify this?
In what gear and at what speed do you see this?
Very small delay? 2 secs, 1sec, half a sec?

Not that I'm saying our's DOESN'T do it, but it's that I've never noticed, and no matter what I've done, I cannot see a problem with the way it drives.

I'm out in the 500TA later this afternoon, so I'll experiment again.

Regards,
Mick.

It doesn't particularly affect the drivability it's just annoying and shouldn't happen

My Mazda you take your foot off and there's an instant retardation by the engine, on our fiat do the same and it takes a fraction of a second to respond maybe 0.3-0.5 seconds, enough to notice but that's about it, before it starts to engine brake, maybe I'm being over sensitive or its just the car/marque is new to us?

Just back in and having a cuppa.

I had a play and a think whilst I was out. Still no sign of a rev hang upsetting my driving .................. but I reckon I've sussed out why I don't recognise the problem.

We drive a Twinair. They are renowned for lack of engine braking. We've discussed it on here on a few occasions, and I've posted about it too. I think it's something to do with the Multiair system and how it shuts down when you lift off so there's no pumping losses. Maybe someone could clarify that for me?

Take your foot off, the engine goes quiet, and you roll along only slowing down by dint of rolling resistance and wind resistance.

Also, if I come down our lane in 2nd ......... it's steep, maybe 20% .......... I still have to brake hard. May as well come down in neutral.

Try that in our other car - 1.6 16v Clio - in 2nd gear and the engine holds you back.

Near here, there's a 60mph limit that goes to a 40, then a short while later into a 30 limit. Lift off as you approach the 40 and the Clio slows down. Stay off the throttle and the Clio drops to 30 just as you hit the 30. Quite neat I think.

Try the same trick at the same speed at the same point with the 500TA and you'll be doing 44mph when you hit the 40, and doing 40 when you hit the 30. ie the 500TA needs the brakes, when the Clio doesn't.

Not sure if this is a good thing or a bad thing, but the two cars behave very differently when you lift off ................ but it's nowt to do with "revs hanging" and everything to do with engine braking.

Cheers,
Mick.

Mick F said:

......... but it's not to do with "revs hanging" and everything to do with engine braking.

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Well, what you described meets my definition of the rev hang as "an undesirable characteristic of modern cars. When throttle is closed quickly, engine speed does not drop instantly but decays slowly due to artificial delay programmed in the engine control module (ECM) by car manufacturers."

If you were to connect an LED (with 1kOhm resistor) to one of your fuel injectors, you would see that it keeps injecting fuel for some time AFTER you lifted your foot off the throttle pedal. In effect this is the same as if you did not lift the foot fully when you intended to slow down and it definitely reduces any engine braking you expect/need/get.

I personally do not see this as a desirable trait in any motor car.

aquasurf said:

.......... I personally do not see this as a desirable trait in any motor car.

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Why?
What difference does it make to you?

I've described the TAs lack of engine braking, but does it matter?
If the fuel is still being injected for a short while when you lift off, so what?

The car is an absolute JOY to drive.

Regards,
Mick.

Mick F said:

.....The car is an absolute JOY to drive.

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Mick, I understand from your posts that that you do not have a problem with the topic under discussion. It was started by a person who perceived a problem and sought explanation. I primarily responded to him and others who felt the same way.
I never tried to convince you that your car has a problem when you repeatedly and clearly stated how happy your were. Enjoy driving your motor car. I wish we all were as lucky as you.

That's ok!
Sorry, but I do tend to go on a bit.

I'm still a little confused about what the problem is and how it affects the cars that are affected.

What does it do to upset the drivability?

Thanks,
Mick.

Mick F said:

....What does it do to upset the drivability?

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The first post in this thread dated 21-03-13 described it. Also the following 2 posts made in 2 weeks after the first.

Mick F said:

What does it do to upset the drivability?

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aquasurf said:

The first post in this thread dated 21-03-13 described it. Also the following 2 posts made in 2 weeks after the first.

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Sorry again.
You still haven't answered, and all the posts in this thread haven't said.

What does it do to upset the drivability?

I understand what happens, but what does it do to upset the drivability?
What upsets the driver?

Please don't dismiss me. Educate me.

Thanks,
Mick.

Mick F said:

....what does it do to upset the drivability?

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Mick, there is a link in your post No. 19 to my website. In section "Does the QREVS device work" there is a video and graphs. It shows how one of my cars behaved before and after I removed its rev hang.

Some drivers notice the mismatch between revs and road speed when upshifting gears whilst others may not see/hear it or care about it.

Reading comments about the rev hang on various websites I learnt there are 3 groups of drivers: first one hates it, second one does not care and the third actually likes it as it apparently makes (slow) shifting of gears easier for them. I say, to each his own.

I find it more pleasant to drive a car without rev hang as it brings me enjoyment without adjusting my driving to suit the car. This is how I have been driving manual cars since getting my licence in 1972.

Mick F said:

Sorry again.
You still haven't answered, and all the posts in this thread haven't said.

What does it do to upset the drivability?

I understand what happens, but what does it do to upset the drivability?
What upsets the driver?

Please don't dismiss me. Educate me.

Thanks,
Mick.

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Mick, I notice Aquasurf hasn't answered your question about the driver experience - maybe he's posting on vw, honda, lexus, audi, ford, subaru and mazda forums about his qrevs device.

I've never noticed this in my 1.2 Panda or 1.2 500 or my subsequent Audi A1 or 1 Series BMW and I enjoy the occasional spirited B-road blast.

However, our works hack Toyota Aygo exhibits this trait under heavy throttle, high revs and quick gear changing. When changing gear in these circumstances, the "off-throttle" engine revs are still relatively high as you feed the clutch back in resulting in a jerky gear change. It's a bit uncomfortable for passengers and makes the driver seem uncoordinated. More concerning it's probably shortening the clutch life.

I don't know if the hanging revs is a general characteristic of the 3 pot Aygo engine or if there is some software device behind the scenes so can't endorse Aquasurf's posts about this being built in to modern cars.