My lightened flywheel journey - a video diary...

[Aerial_stu]

So, after much consideration, I decided I would attempt to fit a lightened flywheel.....myself.

I've never taken an engine out before, so, if you're interested, follow along on my YouTube channel.

Subscribe to get the next episode....

 

 

 

[Andy135]

Subscribed. Good progress so far. Well made videos too.

[Aerial_stu]

Thanks, two more to come soon!

[ptr_drvr]

I'll give this a watch after work.

[David_Stamp]

Subscribed also. Good videos. Is it the Caterham lightweight flywheel you are using?

[Aerial_stu]

Hi David, nope, it's the TTV version.  

[Andy135]

Watched #5 last night. Well done for a smooth start-up. No major snags it seems?

Very curious to hear your thoughts on the driving experience with the lightened flywheel once you're out on the road. All the promotional material I've read across various sources suggests faster engine (and therefore road) acceleration and greater engine braking - my question would be whether this manifests itself as a vehicle that becomes harder or easier to drive smoothly.

[ScottR400D]

Harder. The purpose of the flywheel is to store  energy to smooth out the inherent fluctuation of an ICE and the fluctuation between acceleration and deceleration. So a car with a (too) light flywheel is difficult to drive smoothly. 

However, most reputable suppliers' lightened flywheels won't be too extreme. Many models of 7 come out of the factory with a lightened flywheel and I know several people who've gone further with a Premier Power flywheel and swear by them. 

 

 

[Andy135]

#8, that's exactly the conclusion I came to when working from first principles, so I'm curious to hear if peoples' real-world experience bears this out.

Another question - does more engine braking increase the risk of locking up the rears when coming off throttle? Presume so.

I should add that I really like the idea of running a lightened flywheel, but I'm mindful of the law of unintended consequences before I make the investment...

[Aerial_stu]

Well, although I'll need to wait for better weather to test properly, I have been round the block.  Mainly to give confidence nothing would fall off.  
 

I did a Dragy 0-60 test and the best I got was 5.33 seconds.  There are lots of threads on here about lighter flywheels but I wanted to do a real benchmark test, so will report back with what improvement I achieve.  I'll ensure I don't loose weight before testing again!

All the concern about a rougher idle have been quashed, no change. 
 

I've only knocked off about 3kg of mass, I believe the Premier Power option includes a lighter clutch and knocks off about double that.

Anyway, subscribe to the YouTube for updates, one coming soon on a slight rectification of a mistake I made (pointed out by a reputable person).

Stuart 

[DanRo]

I have only ever had a lighter flywheel on mine so I can't make a direct comparison to a standard set up.
 

What I do notice, compared to a non-Seven, is that the extra engine braking enables speed to be adjusted with the throttle, to a greater extent. This allows smoother progress on a twisty road because I'm not having to move between 2 pedals so frequently. It also makes the car's attitude more responsive in cornering, although it can tuck in a little alarmingly, if I have to come fully off the throttle mid-bend. 
 

I think the videos are great Stu. The more of these films there are available, the more many of us will develop the confidence to have a go at stuff. 

[Aerial_stu]

Thanks Dan

[ScottR400D]

#9 "Another question - does more engine braking increase the risk of locking up the rears when coming off throttle? Presume so."

Yes. If your a bit clumsy....... 

[ScottR400D]

#10 "I've only knocked off about 3kg of mass, I believe the Premier Power option includes a lighter clutch and knocks off about double that."

Remember, it's not just about how much weight is reduced it matters where the weight is reduced too. 

[Simon420R]

The thing I've found rather disconcerting about driving a car with a lightweight flywheel is the level of deacceleration when lifting off the throttle too fast in traffic. I live in London and often the more aggressive drivers will be inches away from your rear bumper. I'm extremely cautious about lifting off too quickly as I know they won't be paying enough attention behind me to notice the rapid loss of speed. I've fitted a pair of high level LED brake lights to help the situation but obviously these don't go on when lifting off the throttle. 

[krisfl]

I went from a stock Ford flywheel on my Sigma to the Premier Power Ultralight flywheel and clutch. It offers no power or torque at the wheels, but a vastly improved response by removing about 6-7kg of rotating mass. The car now revs like a motorbike and "feels" liberated - like it has another 25bhp. The reality it just has less weight to spin up and slow down.

Rev matching + heel and toe on the way down is now a delight, and ripping up through the gears the car is transformed.

In terms of driving in traffic, it required me to relearn my car over the first 150miles or so. But after that I was slouching through traffic as before. The bite is much more aggressive, and the pedal action is now a bit heavier (due to the new clutch and master cylinder etc as part of the upgrade) and with the revs rising and falling so much quicker, it was initially easier to stall. Engine braking is also much increased, which i like a lot on flowing roads as I find the cars road speed can be adjusted much more smoothly.  But as I say, after 150 miles or so, I was as smooth as the day I passed my IAM exam ;-)

Personally I'd never go back. And I'd recommend Premier Power to anyone, they're awesome. But I'd say light flywheels won't be to everyone's taste. And of course a heavier lightened flywheel, like the CC one (if that makes sense) would dampen some of the effects I describe above, keeping the original clutch and feel, and so may be better for some people/tastes.

Bottom line, in my view, the sigma is held back by an unnecessarily heavy flywheel. I'd say most people would prefer the character of at least a mildly lighter flywheel, hence the Super Sport 140 upgrade was so popular on the older fixed cam sigma...

The ONLY downside is my local MOT station can no longer pop it onto their ramps in their massive safety boots. I now have to do it for them 

[ScottR400D]

#16. I'd agree with all of that, it's exactly what I would expect and have partly experienced.

My Duratec has the 'standard' lightweight flywheel but    rev matching, throttle response is very good. The engine braking often means that you can avoid the brakes for long periods when out for a 'cruise'. 

Your comments about the Premier clutch feel are familiar but people always get used to it quickly.  

The only thing I'd disagree with is your last point. I'd see that as an upside........
 

[Rex]

My Zetec engined Seven has a lightened flywheel. I really like it on the way up, but it does have a tendency to stall on the way down. I hooked up a very crude cruise control which pretty well solves the problem. If I have to brake suddenly, I can feed in the proper revs by hand while keeping my foot on the brake.