Hi all,

after seeing a couple of videos on youTube of vRS's with SMF's making some awful rattling sound, I started wondering; why doesn't my car (petrol) do that despite having a SMF?

Thanks,

Joe.

Edited 7 February, 201115 yr by TriggerFish

Have you not answered your own question there,

Why? Do petrols not need DMFs then?

Isn't the main purpose of dmf's to iron out crankshaft vibration and spikes in power delivery, something petrol cars don't suffer from

Edited 7 February, 201115 yr by Mattcooper79

That's what I thought - for smoother running or tickover.

So, would in theory a larger, powerful petrol engine (say 2.0 TSI) need a DMF too?

like has been said above the job of the dual mass is to stop vibrations from the output shaft on the gearbox.

obviously the lighter the flywheel the less effect it will have on stopping vibrations (more vibrations from a diesel engine)

also more and more petrol cars are also switching to dual mass flywheels now as the buyers expect a smoother ride.

My understanding is higher powered lower cylindered petrol engines benefit from dmf to help create a smooth sounding engine but not to the same extent as diesels

more or less all cars will be switching to dmf in the near future as manufacturers strive to make cars as smooth as possible.

in theory its not a bad design just needs a different style of driving to a smf. i killed my first one in 15k booting it in high gear low revs.

Diesels produce incredible torque spikes at idle. As well as being noisy, they can damage gearbox components, or even clutch damper springs. DMF is used in some petrol cars though.

Loads of modern petrol turboed cars have them the 1.8t for example all have them

1.8t with smf's chatter too, but it isn't as severe as the diesels

Right, ok. Thanks all. Cleared that up - I originally assumed it was a derv only thing.

Thanks.

1.8t with smf's chatter too, but it isn't as severe as the diesels

1.8T come with Dual mass on all engines dont they? S3, TT etc.. all do.

it might be only the ones with 6 cogs?? not sure tho and i think big jase is referring to the 1.8t with the single mass conversion

My post was referring to a dmf to smd conversion on a 1.8 t

so what is it that causes the chatter? its easy to tell what the dmf does really i use my car for a driving school and if someones clumsy with the clutch without any revs at all it vibrates like mad! but my fiesta tdci was dual mass and that was really noisy! even from new! without it i bet its terrible unless u add a fair few revs on pulling off? could you liken it perhaps to a petrol with a light flywheel and a paddle clutch? my old glanza had that set up?

As soon as you put your foot down on the clutch the noise stops. Only foot off the clutch in neutral does it make anymore noise that normal

Matt

Thats normal Matt

If you run with SMF then your gearbox wont last long know of 2 people this happened to as a result of fitting SMF loads or noise and lots of cost!!!

There's loads of people running smf's and no issues. Yeah it'll put more strain on it, but not to the extent of everyones gearboxes going bang.

Matt

lots more strain, well maybe ok but for how long is the point, also there maybe a reason why VW decided to fit the DMF

Surely a lot of it is down to how you drive the car?

I'm personally not a fan of the DMF. I like the intention behind it, but it's too costly and not strong enough for the job.

My gearbox shat the main shaft out of the end of itself on the standard dmf?

How do u explain that one then coz they only break with an SMF LOLZ!!!

People have been putting SMF's in pd130/50 for a good few years now. It's not new technology. I'm not disagreeing that it puts more strain on parts, as does a remap, hybrid turbo, bigger brakes etc, but it's not enough to be as bigger problem as you make it sound.

Also, a good point made by leodhasach, if you drive it with mechanical simpothey it'll last much longer, drive like Jason and, well, we know what happens :-p lol

Matt

People have been putting SMF's in pd130/50 for a good few years now. It's not new technology. I'm not disagreeing that it puts more strain on parts, as does a remap, hybrid turbo, bigger brakes etc, but it's not enough to be as bigger problem as you make it sound.

Also, a good point made by leodhasach, if you drive it with mechanical simpothey it'll last much longer, drive like Jason and, well, we know what happens :-p lol

Matt

+1. It's also popular on the 1.8t cars.

Wonder how strong the 5-speed box is in relation to the 6-speed, as I happen to have a G60 SMF and Mk3 VR6 clutch combo here. Apparently they'll fit...