seanmcr6

I really don't understand why so many people say this will destroy your engine on a 996??

I have a full SpecClutch Spec 2+ with LWFW that I bought last fall. Before I installed it, I read a bunch of posts on here that it would destroy my engine and I chickened out and didn't install it. (any of it actually)

however, since then, I've read a lot about club cars and GT3s that run with them, with no issues. They are *basically* the same engine as mine, with different cams, pistons and bottom end (again, from what I understand)

So why can these cars run a LWFW and a 2004 C4S cannot?

Honestly, I'm asking because I've used LWFWs in previous cars and loved them.

sean

jumper5836

I chickened out of well. Though I have a friend with a 3.4 stripper that is has had a lwfw forever and it runs fine while being abused at the track.

TRT41

I have be running a LWFW for the last 3yrs.

atr911

The harmonic balancer on a 996 is in the flywheel. LWFW could increase harmonics on the crank and eventually cause failure. It isn't that the LWFW WILL grenade the engine, it's just that the only time that anybody has seen major damage at the crank and bearings is when there is a LWFW installed.

Jake Raby (sp?) at flat6innovations is pretty adamant about this one. I'm sure you've seen it but: http://www.flat6innovations.com/broken-crank

Just my opinion.

Ahmet

I am not of the opinion that it will hurt your car, but I've known more than one person to install it and get tired of the extra noise + dealing with the grabby-ness of an aftermarket clutch/LWFW and switch back to stock (on street driven cars).

seanmcr6

Yeah, I've read Jake's breakdown about it on Renntech. I just don't believe it's necessarily as severe as that. I mean, that car had 12,000 track miles. That is VERY different usage than I'm going to have over the next 3-4 years. Besides, after 10,000 hard track miles, I would THINK you would be doing a complete engine rebuild anyway?!

sean

seanmcr6

David, what brand LWFW are you running, just out of curiosity?

Topaz330ci

ATR - That must of been you behind me yesterday at the Expiremental farm? Sorry for the OTness...

atr911

What were you driving?

Topaz330ci

2003 Cobalt blue 4S

jasper

The thing is...this example seems to be the only one that has been recorded. Certainly it's the only one making the rounds on the interweb. (OK to be fair Jake cites several cases in his text).

Perhaps Jake or another experienced engine builder can provide more examples, but so far the case of cranks failing because imbalances aren't being checked by dual mass flywheels seems to be very very rare indeed.

Furthermore, if we happily assume that the internet is magnifying the IMS issue, then wouldn't it ollow that this issue is also being magnified? With only been one recorded failure it should follow that the actual failure rate is less than one, and in fact it doesn't happen at all.

In theory, yes, the lack of a dual mass flywheel to dampen imbalance could cause a catastrophic failure. In theory also a little nib of case sealent could come loose and find it's way into a critical oil passage and a bearing could spin, or a flack of dirt could clog an injector and a piston could burn....I could go on but you get the point.

Stuff happens.

atr911

Read up on the posts. There are ample examples and good scientific reasoning for the failures.

I'm not saying ts going to happen. No different than the IMS. Nothing says yours is going to fail. In fact, failure rate is probably less than 5% but it doesn't stop a huge majority of people from installing the retrofit. Why take the chance? The ROI isn't that great either as far as performance goes.

gieseja

My mechanic told me the same thing.

atr911

He was right.

seanmcr6

ROI isn't that great on what? LWFW? really....have you driven one? I don't think you'd say that if you had. The acceleration rate is significantly higher. (so is the RPM loss mind you)

It makes a real and measurable change. Especially if you compare it to.....IPD plenum, or cold air intake, exhaust, etc.

I understand the physics behind it, I do. However, I believe most 996 engines are fairly well balanced to begin with....more to the point, I do not believe that porsche uses a dual mass simply because this engine requires the dampening. Evidence by the fact that they don't use dual mass flywheels for any of their "pure" performance models (read RS models). I believe it has more to do with the everyday drivability of the platform than the specific health and longevity of the engine.

Of course, I'm not an engineer, which is why I'm looking for more *real* info. Jake is someone I trust and believe, however he is only one data point against. I have received lots of replies from lots of people who use their 996's exactly like I do and they have never had an issue.

I guess I'm looking for a second or third "Jake" to really convince me this is a serious detriment to my engine's health.

Wouldn't AASCO and Spec be out of business if their flywheels were destroying engines?