Aasco flywheel is here. - Page 2 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

timothy · 05-15-2009, 02:35 PM

Just wanted to chime in and say thanks for a very informative (and civil!) discussion.

Jake Raby · 05-13-2009, 05:34 AM

If your car is a 5 speed, I have a brand new one in the box that I'll let go..

Ed,
If you felt a difference in vibration in the driver's seat what do you think the engine felt??

I want to make it VERY clear that I am not discounting any company's product! My concerns are with the CONCEPT much more than any company as failueres have happened with all brands thus far..

JAAY · 05-13-2009, 05:55 AM

I'll call you. When do u get I ?

tholyoak · 05-13-2009, 06:07 AM

I'll add my $0.02.

1) These types of crank failures were seen with the M64 (aircooled 964/993) when people pulled off the front (harmonic balancer) pulley and added a single mass pulley when ditching the AC, like the RS versions of these cars came with from the factory. Guess what, with track use, the cranks snapped.

2) The M97 3.8 engines come with a different front pulley that incorporates a harmonic balancer, might be worth looking into if you have a LWF.

3) I'm not sure of the cars Jake is referring to, but most people doing LWF swaps on the M96 platform are not doing them correctly. They simply swap the DMF for the SMF and use a stock unsprung clutch disk. Well Porsche and other manufactures have used SMF for sometime, and guess what, they use a sprung disk. Why? Because driveline vibration and shock has to be taken up somewhere. If there is no sprung component (either DMF or sprung disk) guess where all that shock is transmitted? Right to the crank. So using a single mass flywheel with an unsprung disk is going to make the harmonic vibration issues even more of a problem.

Even if you read the LUK site (the manufacturer of the DMF) they state this was simply done for noise and making cars easier to drive. And yes my car has an Aasco LWF with a sprung disk.

-Todd

Jake Raby · 05-13-2009, 06:19 AM

Jaay,
I was on the dyno when you tried to call.. The engine is cooling now, so I have a few minutes.

Todd, you are sooooo righttttt!

The rigid disk is hell on the harmonic issues, the sprung disk is the key to the LWFW install thats done thoroughly.. Everytime I use a LWFW it is done with a sprung center disk, but I only do it if I build and balance the entire engine's assembly..

But guess what... Most people just don't use their brains.

Topless · 05-13-2009, 07:43 AM

Totally with Todd and Jake here.

We want the balance issues, harmonics and shock loading to be absorbed by the flywheel and not the crankshaft. The dual mass flywheel serves this purpose well. If we eliminate the DMFW we need something else to take up these issues to preserve reliability. Top Porsche race teams use LWFW but always build and balance the motor from the ground up taking these issues into consideration. You would never see Penske or Farnbacher bolt on an aftermarket LWFW without a complete motor balance and harmonic dampeners in place.

One of our regular track hounds "Insite" from Atlanta recently tossed his motor. He put a lot of track miles on that 2.5 but it failed shortly after the LWFW install. I wonder now if the two are related. Something to consider.

edevlin · 05-13-2009, 09:54 AM

"The rigid disk is hell on the harmonic issues, the sprung disk is the key to the LWFW install thats done thoroughly.. Everytime I use a LWFW it is done with a sprung center disk"

So would it be worth while for me to replace my 40K old stock clutch with a Spec clutch or similar unit that has a sprung center disk? How much would that compensate for harmonic issues without going in and rebalancing the whole engine assembly?

Ed

insite · 05-26-2011, 12:00 PM

Quote:

Originally Posted by Topless

One of our regular track hounds "Insite" from Atlanta recently tossed his motor. He put a lot of track miles on that 2.5 but it failed shortly after the LWFW install. I wonder now if the two are related. Something to consider.

FYI, i was using the LWFW with a spring centered clutch. i'm pretty sure it wasn't a fractured crank, but i haven't opened the motor yet. the engine had 140k miles on it.

Jake Raby · 05-27-2011, 05:13 AM

Quote:

Originally Posted by insite

FYI, i was using the LWFW with a spring centered clutch. i'm pretty sure it wasn't a fractured crank, but i haven't opened the motor yet. the engine had 140k miles on it.

The material on the magnetic drain plug that you posted a few days ago look like rod bearing material to me.. This can be from a compromised crank that fractured at the radius of a rod journal and toasted that bearing. This is exactly what happened to Lon's engine, when he sent it to me he thought that it had lost a rod bearing, when it arrived I found the broken crank before I even disassembled it. Who knows, only a teardown will prove what the real cause is.

The sprung center disc only helps with harmonics and frequencies that are sent upstream through the input shaft from the drivetrain. The sprung center disc does nothing to aid in the harmonics generated by the engine that cannot be absorbed by the second mass of the flywheel after it has been removed and replaced with a single mass.

Gilles · 05-27-2011, 11:29 AM

Quote:

Originally Posted by Jake Raby

The sprung center disc only helps with harmonics and frequencies that are sent upstream through the input shaft from the drivetrain. The sprung center disc does nothing to aid in the harmonics generated by the engine that cannot be absorbed by the second mass of the flywheel after it has been removed and replaced with a single mass.

Jake, can the loss of the dual mass flywheel be compensated with an UDP that has a harmonic balancer built into it? like the ones offered by RSS or ATI Racing..?

http://www.atiracing.com/products/dampers/damper_tech.htm your comments will be greatly appreciated.

Gilles, across the street from El Toro base...

.

Jake Raby · 05-13-2009, 10:57 AM

The sprung center disc at least gives some of the harmonics somewhat of an absorption point...

Darkhamr · 05-13-2009, 05:39 PM

I have the Aasco LWFW with a sprung clutch. Acceleration and responsiveness is great, shifting is butter smooth. I absolutely love it other than the rattling noise in neutral. Because of location / access this is the first vehicle I haven't worked on the motor myself, but do these motors not have balancers in the crank pulleys as well?

Jake, I am fully aware of the damping I am losing and the potential failure it could cause, but it is a risk I've decided to take for the type of driving I do. You clearly know far more about motors than I ever will, but do you really need to repeat multiple times that anyone putting in a solid FW is brainless or an idiot?

Jake Raby · 09-27-2009, 08:28 AM

Yes I have many clients who would be willing to share their experiences of the 3.6 big bore engine with you.. Some of these have my Stage I and Stage II versions of the engine.

We do ALL our own evaluation work, we do not depend on our purchasers to give us feedback on new products.. Our fleet of 4 M96 powered test cars helps us to understand our components on the street and track from DEs and AXs to Land Speed Racing.

These same track cars see 83 mile per day round trip commutes.