Well as some of you may know i'd been having clutch problems with my tuning box'd VRS and it was starting to slip. I wanted to go for a decent upgrade due to going for about 200bhp / 350lb/ft. But i didnt really like the noise of the smf and the gearbox chatter.

So I spoke to Nick @ Jabbasport who talked to me about the SMF kit they sell - I said about the noise and not wanting it to be too annoying as its a daily driver and my family car too. So the suggestion was to put the weight of the SMF up a bit. The original SMF's are about 6 KG - So they had one machined with a bit more meat to it - to try and stop quite so much gearbox chatter.

The new kit arrived and over the last 2 days i've fitted the new kit. The new SMF tips the scales at 7.6 KG. I finally got it out on the road lastnight and stalled it 14 times in under 10 minutes! But I've got a mate who live close by with another PD130 running a Helix kit and he came round to see the car lastnight. His gearbox chatter and vibration is far louder than mine! the car revs up really well and once its been bedded in for a few miles everything should settle down nicely!

Top job Jabbasport!

Thing is - the lighter they are - the less wasted power. There was a thread where the physics of lightened flywheels was calculated....

I have a helix and it's not really bad at all.

Glad that you're happy.

Can I sould a lil silly please?

I know the DMF smooths out the power from the engine, but what's the difference between a Dual and a Single? Is a Dual twice as heavy, or does it consist of two parts? Why is a Single better for Performance and a dual for comfort??....

Ya know what, I'll google it.. lol!

Can SMF's damage the gearbox and drivetrain?

Can I sould a lil silly please?

I know the DMF smooths out the power from the engine, but what's the difference between a Dual and a Single? Is a Dual twice as heavy, or does it consist of two parts? Why is a Single better for Performance and a dual for comfort??....

Ya know what, I'll google it.. lol!

A DMF is like two flywheels connected together with basically a big spring, so any vibrations between the gearbox and engine is taken up by this big spring.

OK, for anyone else wondering, this thread over at uk-mkivs has quite an informative opening conversation (especially if you've just watched the vid above).

Joel, one guy with a 230bhp bora mentions a SMF killing his gear box.

solid or single mass fly wheel????????? - uk-mkivs

Oh,.... and Polo6n1600i, it sounds awesome!

Rob

nearly 40k on with the Helix and SMF all going good

Noticed the car really revs up quickly. Also the rolling inertia of the car when you lift off the throttle is a hell of alot less than the original DMF - the car just rolls forever! managed a 63.8mpg run from work!

Noise at tickover doesnt bother me as I jump in the car start it and drive off it's never really sat at idle.

However when i get up some speed I do get a bit of a howl off, what sounds like, the gearbox especially under load - not sure if thats from the clutch and it will take a good 1000 miles for it to settle down and bed in!

Yeah that howl will allways be there when in higher gears such as 5th and 6th, not quite sure what causes it but the guy at Jabbasport said to expect it and its normal.

A lighter SMF is actually a good thing for performance :Lightening

A lighter SMF is actually a good thing for performance :Lightening

Agreed with reservations...

1) Depends on the use of the car and the traffic conditions. Can you drive it OK on the road or will shunt, noise etc drive you nuts. (personalities differ...)

2) Lightening the flywheel improves performance most in lower gears. This is due to gearing acting as a multiplier on the power otherwise lost in the extra KGs of the flywheel. i.e. It goes faster in lower gears.

3) At higher speeds and in higher gears, 4-5KG of rotating mass won't make much difference. You can save more by buying forged, lighter wheels and/or tyres.

4) Flywheels are sized assuming the car is driven by an irrational, angry, incompetent chimp who can't drive, will always stall, and then blame the car for it. AKA salemen and managers.

I've noticed the car is definately quicker through the gears - and 3rd lights up the front wheels!!!

I'll have to adjust my driving style slightly to compensate for the slight lack of engine braking!

When I went from 1.4 16v Petrol Fabia to vRS Fabia I almost hit the windscreen every time I tried to engine break by going into 2nd, cuz that was the norm on my petrol Fabia.. took me a day or two to work out that it was 3rd for engine breaking (at a pace I liked) in the Vrs..

Try using 2nd? (If like me, you used 3rd before)

.

yeah - I noticed the same thing - just 1 gear lower seems to be fine!

You should not be using engine braking anyway, it is needed on old cars that have sh*te brakes (like my Seat), I wouldnt put my gearbox under unneeded strain on a modern car though.

Not disagreeing, but when I was being taught to drive I was told to downshift in accordance to my speed, supposedly keeping the car under more control and to try and advoid the need for coasting.

must admit my jabba smf is way quieter than my 4kg spec smf,standard dmf wieghed a wopping 27kg's!!!!!!

Not disagreeing, but when I was being taught to drive I was told to downshift in accordance to my speed, supposedly keeping the car under more control and to try and advoid the need for coasting.

That's true - you should brake down to target speed, then drop it into the appropriate gear for that speed. I.e. single gear change