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How fly can my flywheel be?

Ideally if using a LWFW on an M96 you should get the crankshaft balanced with it, obviously that requires an engine tear down.

My flywheel (DMF) became imbalanced and snapped the crankshaft in two, yes it is heavier but the failure is not necessarily due to weight but more the harmony between the two parts.
 
So, I spoke with Ken today.

Lovely chap. Long story short, if would happily fit a lwfw for me. However if it were him he would not fit one on a 7.1 c2s.

So that leaves me with:

PARR Motorsport yes
RPM yes
Ne no
Demort no.

and forum members pretty even split too.
 
PARR Motorsport yes ... its work for them
RPM yes ... its work for them
Ne no
Demort no. .. ive seen the results when it doesnt go to plan but im not a yes or a no ... its your choice and dare i say .. gamble .

Ken .. he sells them .. he has an interest in selling you one .. he said no he wouldn,t do it if it was his choice ...

For me that speaks volumns.


Ken ...
:thumb:
 
RXP. said:
So, I spoke with Ken today.

Lovely chap. Long story short, if would happily fit a lwfw for me. However if it were him he would not fit one on a 7.1 c2s.

So that leaves me with:

PARR Motorsport yes
RPM yes
Ne no
Demort no.

and forum members pretty even split too.

Good to talk to you today.

I probably should explain in a little more detail my reasons for that view.

We have on many variants over the years fitted LWF from pre 89 to 997 onwards including many GT4s and so on.

As you may know we do have a performance outlook as well as normal routine work and servicing etc. We use a lot of datalogging rather than making the assumption of fitting and assuming all is well.

There are certain models which respond well to LWF and some that don't. And that statement is not in the sense that one works better than on another model, but more on the effect of the engine and power.

I won't give out full details but suffice to say
- don't assume because the LWF looks nice and shiny and made by a CNC process that it is 100% perfect and balanced.
- don't assume that the LWF is not affecting your engine performance just because you don't see check engine lights (CEL) on the dash
- don't assume that it is not retarding ignition without you knowing it

As some may know, misfires trigger a CEL when they exceed a certain threshold in a certain timeframe. We have seen (in a control test) a DMF giving no misfire counters against LWF giving misfire counters. The design of the LWF is sometimes at higher RPM the pickup is different.

As also stated certain engines are stronger than others. We have LWF on 1000+hp turbo cars, but the whole assembly is perfectly balanced before installation.

We recently finished a couple of custom pre 89 engines that we put onto full Motec control and on one of those we were able to trace issues down to the LWF. When we pulled that and checked, despite it being new, the LWF was not 100% true. When this was corrected, issues went away.

Harmonics do play a part. Without going into a long story, engine mounts for example whilst giving improved handling, can also cause power reduction (minor) due to knock control. If you think of the knock sensors on either bank, they are looking for noise. You create more noise, the ECU pulls back power until it no longer senses knock. We are not talking huge amounts but when you build two cars identicial and one just seems to that that little extra and you try and find why, amazingly it was engine mounts being semi solid that caused the issue.

AASCO are the best we have used as an FYI and many just rebrand their product.

I just wouldn't personally do it on NA 996/997 engines - GT3 etc is fine. The only time we have on those particular models is when building some track day engines and then the whole assmebly was balanced.

Ken
 
Flywheel

RPM fitted mine 15k ago, had a standard clutch fitted as I was a bit worried about commuting with an on/off clutch, I love the chatter from the engine and the way it revs, and I have had no problems with it. Would I do it again, yes.
 
Hey Ken,

Greatly appreciate both the time you gave me yesterday and the response today. As a reference point for detailed info and opinions on this subject.

Will be in touch soon.
 
Re: Flywheel

rocco996 said:
RPM fitted mine 15k ago, had a standard clutch fitted as I was a bit worried about commuting with an on/off clutch, I love the chatter from the engine and the way it revs, and I have had no problems with it. Would I do it again, yes.

Hey bud,

was this part of a rebuild on the csr programme? balancing the flywheel to the crank?

Or straight bolt on?

I believe rpm use the TTV flywheel?
 
Bolt on, the only 'engine' work was the LWF and clutch, there was certainly no charge for balancing and I wasn't told it was required. I don't know what make they used, I'm sure they will tell you if you ask them.
 
996ttalot said:
RXP. said:
So, I spoke with Ken today.

Lovely chap. Long story short, if would happily fit a lwfw for me. However if it were him he would not fit one on a 7.1 c2s.

So that leaves me with:

PARR Motorsport yes
RPM yes
Ne no
Demort no.

and forum members pretty even split too.

I just wouldn't personally do it on NA 996/997 engines - GT3 etc is fine. The only time we have on those particular models is when building some track day engines and then the whole assembly was balanced.

Ken


Hi Ken,

You have previously fitted a LWFW to an M96 and this was as a bolt on, so no dynamic balance to the crank, why then? and why the change of heart?

http://www.911uk.com/viewtopic.php?t=121423&postdays=0&postorder=asc&start=0
 
crash7 said:
996ttalot said:
RXP. said:
So, I spoke with Ken today.

Lovely chap. Long story short, if would happily fit a lwfw for me. However if it were him he would not fit one on a 7.1 c2s.

So that leaves me with:

PARR Motorsport yes
RPM yes
Ne no
Demort no.

and forum members pretty even split too.

I just wouldn't personally do it on NA 996/997 engines - GT3 etc is fine. The only time we have on those particular models is when building some track day engines and then the whole assembly was balanced.

Ken


Hi Ken,

You have previously fitted a LWFW to an M96 and this was as a bolt on, so no dynamic balance to the crank, why then? and why the change of heart?

http://www.911uk.com/viewtopic.php?t=121423&postdays=0&postorder=asc&start=0

We do lots of projects all the time (which I really should get around to posting about) and a project with LWFW turned up some interesting results of not picking up maximum power above 6000rpm. We traced that to the LWFW, replaced with DMF, and problems went away.


When I say problems, remember we are refering to making the cars performance the best it can be and on NA cars that is always tough work to extract power.


We do fit LWFW to certain variants, which don't exhibit the above issue. The only way you would see that issue is live datalogging, which when we are tuning we do.

Just because you fit something to a car that does not exhibit any outward signs of issues, does not mean necessarily that it is performing at its best.


Add this to the fact that a lot of our project cars spend extensive time on track, and that the m96/m97 is lets say weaker than some of the other variants, imo you just up the risk. And to go back to the issue we found, remember that on track, you are generally in the power band for a lot of the time up in the higher RPM.


LWFW are a great upgrade, Porsche fit them to some variants and Porsche also in the past have advised against as well in some cases. I'm just not convinced that all LWFW are a great upgrade.


I have removed the LWFW and put back in a DMF in the project car you provided a link to as an FYI. Ryan only uses that car to and from track and is an exceptional driver on track and uses every ounce of power he can extract from the m96 engine. It was a shame to lose the LWFW from the car, but we have a better product now.


Ken
 

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