AFN: Make Flywheel Easier

Hello,

My AFN has too much power.
Fun! My clutch has been slipping for the last 2000 km since the tuning.

I just got the Sachs Race Sport clutch and a genuine single-mass flywheel from a G60.

'How many kilograms of weight does one typically remove from an AFN?'
Are there any other disadvantages besides an unstable engine running?


Regards,
DJ.

Hello,

If you reduce the weight of the flywheel, in my opinion, you almost only gain advantages. The keyword here is 'rotating mass.'

In addition to the engine performance, there's a minor drawback (although a forum member who made the modification claims it's barely noticeable).
You'll lose a bit of torque, but you'll gain some extra power and a faster 'revving' speed.
350 Nm isn't exactly a small amount for an AFN, so I think you can handle it.

How many kilometers has your clutch been used? I also have an AFN, but in an Ibiza, and mine has only slipped a couple of times so far, and that was when the car was fully loaded and going uphill .
I have a little more power, , but 'only' 340 Nm of torque.

Hi,

Can you explain the term 'loss of torque' to me?
Is it because of less mass, or something?

I actually prefer high torque because my engine revs up quickly anyway .

My original clutch has 120,000 km (approximately 75,000 miles) on it. It doesn't slip very often, but if you 'dump' the accelerator pedal in at around 2000 RPM, it can sometimes slip a bit.

Well, I have all the parts, so I'm going to install them.
The flywheel is really giving me trouble.

Some people say you feel nothing, while others say it's like this... or that...
And now I have to hear that I'm losing torque...

Best regards,
DJ.


PS: Whose software is this? How many horsepower does it have?

Exactly because of the lower mass.

But don't worry too much about the torque; it will be in a minimal (and probably hardly noticeable) range, .

You can certainly calculate that, but I can't tell you the formula for it. You would need someone who specializes in formulas (and I'm sure there are people here in this forum who ).


P.S. Whose software is that? How many horsepower?

From a tuner I trust , a small tuning shop is certainly not known.
The software is redeveloped after each tuning stage. Power output is 172 hp according to the DZR (German tuning regulation), and 169.8 hp according to the power curve.

Okay, then I'm relieved!
Okay, I'll probably have it installed and running by the end of March.


Let's say a good 170 horsepower which isn't bad, it has to run like a beast!
How about the soot?
My car doesn't produce more soot than before .

Mine has more torque, but almost 20 horsepower less... it's strange that it can fluctuate like that .


Regards,
DJ.

Mine has more torque, but almost 20 horsepower less... it's strange that it can fluctuate like that .

It probably has to do with the components that were installed .

What about the soot?

Ask all those 2.0 16V engines, or the 'smaller' 1.8T engines, that are trying to keep up .

Under normal operation, you won't see any soot, but if I give it a lot of gas, it gets dark . However, it's not a big problem right now because the vehicle is partially disassembled in the workshop, and phase 2 is waiting for it, including things like a DRW transmission.

Oh, I see, so...

My exhaust system is not very loud at all; it's just tuned to be quiet, and that's why the performance isn't going to be that high.

I don't want to say too much about the components .
But you won't have more than one additional turbocharger plus fuel injectors .



Regards,
Deee jaaay

PS: Where are you actually from ?

Okay, we're getting a little off-topic .



But you won't have more than one turbocharger and a few injectors.

You'll laugh, I'm running with original injectors (which is why I can't get more power right now ). I've installed some other components, and right now it's not optimally tuned; it was basically a temporary solution for the further modifications.

I would say let's discuss everything else via private message. If there are any updates on the original topic, we can continue the conversation here.

Okay, you're right!


Regards,
DJ.

@ dj1 and sunny:

Sorry guys, but when I read through what you've all been posting here, I almost felt sick .

I couldn't help but correct a few technical inaccuracies so that you don't spread misinformation!

The flywheel of an engine serves to filter the torque pulses that occur during each working stroke of a cylinder, thereby reducing torque ripple.
This is not only about comfort, but it also protects nearly all subsequent components in the powertrain from excessive torsional vibration.
Finally, the engine also needs a minimum amount of rotational inertia in the idle speed range to "stay alive," meaning to bridge the time between successive combustion cycles.
When starting, the flywheel also acts as an energy storage device (kinetic rotational energy), which helps prevent the engine from stalling easily.

A change in moment of inertia does not affect torque and power, but only the torque ripple.
Furthermore, it doesn't make sense to discuss how many grams or kilograms you have reduced the weight of a flywheel by, because the mass distribution across the radius is crucial .
You really need to take the trouble to calculate the moment of inertia, because it makes a huge difference whether you rotate the mass on the outside or on the inside .

Okay, sorry, but this really had to happen now.

Regards,
Alex.

'Dangerous half-knowledge' on my part .

I can follow your explanation so far, except for the terms 'torque ripple' and 'torsional vibration excitation.' (Perhaps you could provide a brief explanation of these terms ). (A search for these keywords didn't yield any new insights).


This part.

Not least, the engine in the idle speed range also needs a minimal rotational inertia (better: moment of inertia) to simply 'stay alive,' meaning to bridge the time between two successive working cycles.
When starting, the flywheel also acts as an energy storage device (kinetic rotational energy) so that the engine is less likely to stall.

It's perfectly clear to me.



Furthermore, it doesn't make sense to discuss how many grams or kilograms you have reduced the weight of a flywheel by, because the mass distribution across the radius is crucial.
You really need to take the trouble to calculate the moment of inertia, because it makes a huge difference whether you rotate the mass on the outside or the inside.



We didn't even talk about that , but I understand that too, therefore.
I'm sure that can be calculated, but I can't tell you the formula for it. You would need someone who specializes in formulas (which I'm sure exists in this forum).


Regarding the claim that there is absolutely no torque loss, I can only say that I myself had a lightened and balanced flywheel installed in a Polo (1.3 liter with a dual-carburetor). The Polo doesn't have much torque anyway, and on the highway incline, a noticeable before-and-after effect was observed; it definitely took longer to reach its cruising speed. So, if it wasn't due to torque, what was it then?
Furthermore, every time this topic comes up (regarding the flywheel), I hear anecdotal accounts that you can easily lose torque . My own experience, credible accounts from others, and some technical understanding led me to my conclusions.
Apparently, it's dangerous half-knowledge .

Or is my mistake in thinking stemming from the comparison between gasoline and diesel ?

Okay, sorry, but this really had to be done now.

No problem, I can live with criticism. It is also welcome because I believe that is the only way to learn and improve .

Hello everyone;

Unfortunately, donalexo got to it before me.

He is absolutely right .


greetings

and on the acceleration curve, a clear before/after effect was noticeable; it definitely took longer to reach full speed. What was the reason for this, if not the torque?


You need to understand a motor as a 'total work of art.' All components are perfectly coordinated. If you change the moment of inertia of the flywheel, it will have repercussions for the entire crankshaft mechanism.
It can then happen, for example, that the greater inhomogeneity causes the charge transfer to be affected by vibrations.
Ideally, the crankshaft and pistons should be adapted to the changed flywheel mass.

CU.

Hello,

Just to mention it,
Or, just for the record:

Turning the flywheel reduces the rotating mass of the powertrain. This, of course, affects the torque, just as wheels with less rotational inertia increase the torque available to the tires.

However, I'm not sure if a slightly unbalanced flywheel will make a noticeable difference. However, few people here would doubt that genuinely lightweight rims can provide a few extra Nm of torque compared to standard steel rims or even heavier aluminum rims.

Best regards, Georg.

I even strongly doubt it .

Because less mass in the wheel does not lead to more torque being delivered by the engine.
He then only has an easier time using his existing torque to accelerate the remaining masses. In the area of the wheels, this is unlikely to have much impact on vehicle acceleration, as the rotating masses are rather negligible compared to the vehicle's mass. However, the wheel diameter has a significant effect ('leverage').

Of course, this is very noticeable at the flywheel (i.e., the gearbox input), as the motor is supposed to reach its operating speed more quickly. The moment of inertia at the gearbox input is more or less constant.
However, as mentioned before, the entire engine needs to be overhauled.

CU.

Hey guys,

In this thread, "changes in rotational speed" are repeatedly mixed up with "changes in torque."

As donalexo wrote, nothing changes in the motor's torque when you modify rotating masses.

Let's illustrate this with an example of a torque wrench.

If you use them normally, meaning without excessive force or any kind of misuse:
What changes about the torque applied to the screw if the wrench weighs 1 kg or 10 kg?

Sure: NOTHING.

And it's the same with the engine. If it's already rotating, it has the same "pressure" (colloquially, meaning torque), regardless of whether it has a heavy or light flywheel.

What changes is the oscillation and the usable inertia (for starting), which behave as described by donalexo.

m;