[eye30]

I know for sure that my new car's engine is much quieter than the previous one and there is no sign of a chatter or rattle - but I was never conscious of a chatter with my previous car

My 4.5 yo is so so quite that sometimes I think the engine is off.

[Phil №❶]

Isn't there a forum member that works or can check this out at the Czech factory, b4 they bolt them together. Not going to get any sense from head offices, they have nothing to do mechanically with the cars. 

[Doggie 1]

My 4.5 yo is so so quite that sometimes I think the engine is off.

I have a 4.5 year old grand daughter and she's never that quiet that I think her engine is switched off 

[marti30]

My 6 speed 1.6 u2 crdi has always been quieter at tickover with a floored clutch. A few seconds after releasing the clutch the what I now take to be solid flywheel noise starts. The car has been on the road almost 28 months and has clocked up over 74,000 miles @ 62.5mpg (carefully calculated based on odometer readings and fuel consumed).

[AlanHo]

My 6 speed 1.6 u2 crdi has always been quieter at tickover with a floored clutch. A few seconds after releasing the clutch the what I now take to be solid flywheel noise starts. The car has been on the road almost 28 months and has clocked up over 74,000 miles @ 62.5mpg (carefully calculated based on odometer readings and fuel consumed).

Have you ever checked your odometer against a sat-nav or 1 km interval marker boards on a motorway over a long distance. Most odometers and speedos are fast - that is they read higher than the real speed/distance by as much as 10%. This can make a sigificant difference when people compare the economy of their cars.

If you have a sat-nav it would be interesting to see how it compares with your odo.

Also. have you seen this thread - I am looking for some help :-

https://www.i30ownersclub.com/forum/index.php?topic=14272.msg156628#msg156628

[baroudeur]

Also. have you seen this thread - I am looking for some help :-

I have replied on the other thread.

Do you have a close enough relationship with your dealer to do a double check?

Will discuss with them when I book in for the first service next month

[marti30]

 Hello Alan, I was wondering if you'd query my economy claim. I'm aware that speedometers have to be optimistic (and in reality probably over read by about 5%) and that odometers are similarly inaccurate. I lack the gadgets to verify my instruments and haven't made use of the motorway markers. However, a journey that I've made hundreds of times over the years is 110.6 miles in the i30 but used to be 111.1 miles in my 5 speed 1999 Ford Focus 1.6 petrol (which gave me 47mpg, calculated in the same way). Before that my 1995 Rover 414sli gave similar economy and clocked the distance at 113.2 miles. So it's quite possible that my overall 62.5mpg (64.5 according to the dashboard display) is more like a true 60mpg and that the 64/65 that I often get is really about 62mpg. My average speed display is 43mph, what's the true figure likely to be?   

A few seconds after releasing the clutch the what I now take to be solid flywheel noise starts.

Flywheels don't make any noise (at least solid ones don't) because there are no moving parts.  Yeah, ok, but you know what I mean!

I guess the noise could be from the gearbox (half of which is rotating in neutral) or might simply be transmitted via the clutch pedal from the engine bay - unlikely though as it should be well isolated by the hydraulics.

[asathorny]

without wishing to highjack this thread,  , I wish to make a correction on my MPG...   Some time ago I announced that I was getting 44mpg out of my i30 1.6 petrol edition.  Alan responded that this and said this was indeed excellent MPG for a petrol car.  It goes without saying that Alan's observation has totally jinxed me and since then I have been lucky to achieve 40MPG...

I can only assume that I had some extraordinary good luck on a trip to (I think) North Wales, anyhow I wish to revise my MPG announcement :-

Alan, I am averaging 40MPG with very judicious use of the accelerator

[marti30]

'start it up, put it in neutral, let the clutch out and then go round the front of the car and listen on the g.box side of the car, can you hear a distinct chatter, almost like a rattle coming from the g.box? it should only be at idle and when you put your foot back on the clutch it should go away. if this is the case all fingers point to the clutch/flywheel setup being single mass.'
This is the noise I was referring to. It's more noticeable outside the car (although no one else has mentioned it) and starts a few seconds after releasing the clutch pedal.

[komaterpillar]

A few seconds after releasing the clutch the what I now take to be solid flywheel noise starts.

Flywheels don't make any noise (at least solid ones don't) because there are no moving parts.  Yeah, ok, but you know what I mean!

I guess the noise could be from the gearbox (half of which is rotating in neutral) or might simply be transmitted via the clutch pedal from the engine bay - unlikely though as it should be well isolated by the hydraulics.

See post #16 and #22

[2i30s]

I'm amazed that in 2012 a twin plate clutch set up in a modern car could have so much trouble.     in the early 70's ford was using twin plate clutches in the xy,xa and xb gt falcons without any problems, and that's 40 years ago. 

I'm amazed that in 2012 a twin plate clutch set up in a modern car could have so much trouble.     in the early 70's ford was using twin plate clutches in the xy,xa and xb gt falcons without any problems, and that's 40 years ago. 

2i30s, I think you might be talking about something else.

[Phil №❶]

I guess the noise could be from the gearbox (half of which is rotating in neutral)

 

Is that right, I though no gearbox movement until a gear is selected and the clutch engages on the flywheel 

I guess the noise could be from the gearbox (half of which is rotating in neutral)

 

Is that right, I though no gearbox movement until a gear is selected and the clutch engages on the flywheel 

A gearbox has an input shaft and an output shaft running side-by-side, the two are connected (when in gear) via two gears, one on each shaft. There is a gear pair for each forward gear.  The gear ratio is determined by the relative size of the two gears selected. When no gear pair is selected (neutral) there is simply no path from input to output but the input shaft still rotates whenever the clutch joins it to the flywheel.

I should add that that is a simplistic description. 

[komaterpillar]

I'm amazed that in 2012 a twin plate clutch set up in a modern car could have so much trouble.     in the early 70's ford was using twin plate clutches in the xy,xa and xb gt falcons without any problems, and that's 40 years ago. 

Mate that's different all together,

The clutch setup here is a single plate, the dual mass flywheel is a two piece flywheel with some sort of dampening between the two pieces, either springs or rubber, this makes for a smoother engine and a quieter gearbox at idle with the clutch out and in neutral, because all the engine harmonics are absorbed in the flywheel dampening rather than being transmited through the clutch.

The clutch plate hub in a dual mass setup generally isn't sprung either, unlike a solid flywheel clutch, as there is no need to because the dampened flywheel takes the shock load out of the torque transfer.

And I reckon you probably know how a twin plate clutch is setup so I won't go into it, but if anyone else wants to know, ask away.

[komaterpillar]

When a DMF clutch fails its more commonly not the clutch that fails at all but the dampening (springs) in the flywheel and a new clutch is fitted with the new flywheel

[rustynutz]

Here's a video of another Duel Mass Flywheel, this one differs from the one posted in another thread.
This one seems more complicated....