[OpenFlash]

Originally Posted by BEAR-AvHistory

Yeah, Shiv whined & I got banned so what's new. My only issue with your position is Shiv specifically said you did not need anything else in the stock drive train to run the turbo kit. He did not say you did not need anything else over & above the modifications you already made to your cars like suspension, clutch, flywheel, transmission etc......big difference.

We suggest a clutch/lw flywheel to every customer who purchases a single turbo kit. All 10+ 6mt single turbo kit installs we have done in-house get just this. Which is why we have not seen the misfire problem before these 3 customer-installed kits were run with stock flywheel. We always, from day 1, publicaly stated that an upgraded clutch was necessary. Now we will be extending that to flywheel as well. You seem like you have an axe to grind. Get over it. No one cares.

[rismo]

Originally Posted by saxon

So could the transmission be the problem for the at guys, I have a leaking mechatronic sleave and 6500 rpm misfire and it seems like the car should shift but doesnt

MT...... You AT.....

[tmo335tt]

FWIW, I called Spec today and they agreed that the dual mass flywheel is causing the problem and should not be used at our power levels. They said this wasn't anything new and that they have seen it before on other applications as well.

[AK 335i]

Originally Posted by tmo335tt

FWIW, I called Spec today and they agreed that the dual mass flywheel is causing the problem and should not be used at our power levels. They said this wasn't anything new and that they have seen it before on other applications as well.

hey your avatar turned lol. don't shoot me, who's "spec"?

[tmo335tt]

Originally Posted by smi1gj

hey your avatar turned lol. don't shoot me, who's "spec"?

http://www.specclutch.com/

[AK 335i]

Originally Posted by tmo335tt

http://www.specclutch.com/

thx

[JamesM3M5]

Originally Posted by BEAR-AvHistory

In inner & outer ring of the damper are bonded to a rubber sleeve. The rubber sleeve is tuned & it absorbs the crank harmonics, converts them to heat which is passed into the air. So I am not sure what the relevance of “There is nothing that the outer ring of the damper is coupled to besides air” is. Its designed to be coupled to the air to reject the heat it absorbs. That’s also why they are generally made of cast iron because its very good at absorbing & dissipating heat.

You missed the point of the argument. BECAUSE the vibration damper is only spinning in the wind (literally), it is not sensitive to power levels. Since the flywheel is coupled to the rest of the drivetrain to put power down to the pavement, it has a direct correlation to the torque applied. Additionally, the crankshaft speed tone wheel is at the back of the crankshaft, while the damper is up front. Any vibrations that the damper may allow back down the crankshaft to the tone wheel would likely be damped down the length of the crankshaft.

Its interesting to note that every day thousands of 335’s run up through the full rpm range without misfiring but the ones with the extra power are having issues & only some of those according to your post.

... which is the whole point of this thread...

The damper could be an issue here because its common practice in racing applications that the crank damper is changed from the stock one to one suited the characteristics of the new higher powered engine modifications. At least its worth looking at because harmonic balancers fail at different rates based on how fast the specific batch of rubber starts to deteriorate.

Incorrect. The "torsional vibration damper" is upgraded on race engines because of sustained high RPM use, not power levels. The amount of time that race engines see high RPMs is significant, and the heat and forces generated tear the rubber. Happens on stock-power level engines all the time that see lots of track use - E46 M3 and Mini come to mind, since they see lots of track time. TV damper failures on the S54 are more common with single-mass LWFWs, too. That's something to ponder.

What flywheel are you running & are you misfiring? If I read it correctly you did not have the problem only a few did. If that's the case why are you so sure its the flywheel to declare the problem solved in your headline & not something else?

If you had bothered to read the thread, there are 10 single turbo cars with solid LWFWs that do not have the misfire. All 3 of the single turbo cars with stock DMFW have the misfire problem. There is an SAE paper written on the subject. Spec, the clutch and flywheel manufacturer, has also attested to the same phenomenon on other engines. Others have related the same with the Porsche platform. The anecdotal evidence, engineering research, and correlation of the 10 versus 3 all point to the flywheel. Why you and others continue to stand on the sidelines and take pot-shots, hinting that Shiv and others who have researched, tested, and witnessed the problem are all chasing a dream that will never pan out is beyond any level-headed person here.

BTW you might want to check your facts on the "Magnetic Pickup". The CPS is actually 'hall effect' & pretty much vibration proof.

He already referenced the fact that it's a square waveform, and watching it on the oscilloscope means he knows that it's Hall effect. I would attribute this to a typo.

And your lack of understanding on this matter shows in your comment that the Hall effect sensor is "vibration proof." We're talking about torsional crankshaft vibrations that cause the ECU to perceive (incorrectly) that the crank speed has suddenly changed due to a torsional vibration "bouncing" back off the flywheel mass. The unexpected timing of the falling edge of the next tooth is why the ECU thinks the engine is misfiring. This has nothing to do with physical vibration of the sensor. In fact, the Hall effect sensor, since it generates a square wave, is much more sensitive to torsional vibration since it has infinitely more resolution.

[tcw]

So there is no actual misfire occurring? So wouldn't the DMFW ST's be able to run as fast as the SMFW with the misfire detection disabled? Is there a way to disable the CPS misfire detection at these rpms or at least desensitize it?

[OpenFlash]

Originally Posted by JamesM3M5

You missed the point of the argument. BECAUSE the vibration damper is only spinning in the wind (literally), it is not sensitive to power levels. Since the flywheel is coupled to the rest of the drivetrain to put power down to the pavement, it has a direct correlation to the torque applied. Additionally, the crankshaft speed tone wheel is at the back of the crankshaft, while the damper is up front. Any vibrations that the damper may allow back down the crankshaft to the tone wheel would likely be damped down the length of the crankshaft.


... which is the whole point of this thread...


Incorrect. The "torsional vibration damper" is upgraded on race engines because of sustained high RPM use, not power levels. The amount of time that race engines see high RPMs is significant, and the heat and forces generated tear the rubber. Happens on stock-power level engines all the time that see lots of track use - E46 M3 and Mini come to mind, since they see lots of track time. TV damper failures on the S54 are more common with single-mass LWFWs, too. That's something to ponder.


If you had bothered to read the thread, there are 10 single turbo cars with solid LWFWs that do not have the misfire. All 3 of the single turbo cars with stock DMFW have the misfire problem. There is an SAE paper written on the subject. Spec, the clutch and flywheel manufacturer, has also attested to the same phenomenon on other engines. Others have related the same with the Porsche platform. The anecdotal evidence, engineering research, and correlation of the 10 versus 3 all point to the flywheel. Why you and others continue to stand on the sidelines and take pot-shots, hinting that Shiv and others who have researched, tested, and witnessed the problem are all chasing a dream that will never pan out is beyond any level-headed person here.


He already referenced the fact that it's a square waveform, and watching it on the oscilloscope means he knows that it's Hall effect. I would attribute this to a typo.

And your lack of understanding on this matter shows in your comment that the Hall effect sensor is "vibration proof." We're talking about torsional crankshaft vibrations that cause the ECU to perceive (incorrectly) that the crank speed has suddenly changed due to a torsional vibration "bouncing" back off the flywheel mass. The unexpected timing of the falling edge of the next tooth is why the ECU thinks the engine is misfiring. This has nothing to do with physical vibration of the sensor. In fact, the Hall effect sensor, since it generates a square wave, is much more sensitive to torsional vibration since it has infinitely more resolution.

Excellent post. You are infinitely more patient than me

[OpenFlash]

Originally Posted by tcw

So there is no actual misfire occurring? So wouldn't the DMFW ST's be able to run as fast as the SMFW with the misfire detection disabled? Is there a way to disable the CPS misfire detection at these rpms or at least desensitize it?

While there is no real misfire occurring, there is still some degree of CPS error which will effect combustion. The severity of it is unknown at the time but it's still there if one chooses to simply disable misfire detection and not solve the root problem.

[Jeff@TopGearSolutions]

Originally Posted by JamesM3M5

You missed the point of the argument. BECAUSE the vibration damper is only spinning in the wind (literally), it is not sensitive to power levels. Since the flywheel is coupled to the rest of the drivetrain to put power down to the pavement, it has a direct correlation to the torque applied. Additionally, the crankshaft speed tone wheel is at the back of the crankshaft, while the damper is up front. Any vibrations that the damper may allow back down the crankshaft to the tone wheel would likely be damped down the length of the crankshaft.


... which is the whole point of this thread...


Incorrect. The "torsional vibration damper" is upgraded on race engines because of sustained high RPM use, not power levels. The amount of time that race engines see high RPMs is significant, and the heat and forces generated tear the rubber. Happens on stock-power level engines all the time that see lots of track use - E46 M3 and Mini come to mind, since they see lots of track time. TV damper failures on the S54 are more common with single-mass LWFWs, too. That's something to ponder.


If you had bothered to read the thread, there are 10 single turbo cars with solid LWFWs that do not have the misfire. All 3 of the single turbo cars with stock DMFW have the misfire problem. There is an SAE paper written on the subject. Spec, the clutch and flywheel manufacturer, has also attested to the same phenomenon on other engines. Others have related the same with the Porsche platform. The anecdotal evidence, engineering research, and correlation of the 10 versus 3 all point to the flywheel. Why you and others continue to stand on the sidelines and take pot-shots, hinting that Shiv and others who have researched, tested, and witnessed the problem are all chasing a dream that will never pan out is beyond any level-headed person here.


He already referenced the fact that it's a square waveform, and watching it on the oscilloscope means he knows that it's Hall effect. I would attribute this to a typo.

And your lack of understanding on this matter shows in your comment that the Hall effect sensor is "vibration proof." We're talking about torsional crankshaft vibrations that cause the ECU to perceive (incorrectly) that the crank speed has suddenly changed due to a torsional vibration "bouncing" back off the flywheel mass. The unexpected timing of the falling edge of the next tooth is why the ECU thinks the engine is misfiring. This has nothing to do with physical vibration of the sensor. In fact, the Hall effect sensor, since it generates a square wave, is much more sensitive to torsional vibration since it has infinitely more resolution.

OY!!

[BEAR-AvHistory]

Nice rebuttal, guess Shive is in your debt. That being said I have to wonder why a power sweep test measures variables like torque, horsepower, combustion temp, RPM etc. which are then correlated with the damper used & the amount of torsional vibration reported.

Guess we will just have to see if the solution is really the solution when the guys get done buying & installing their new flywheels. I wish them good luck & hope what they have gone through so far is worth the on track gains.

[Carl Morris]

Originally Posted by shiv@vishnu

While there is no real misfire occurring, there is still some degree of CPS error which will effect combustion. The severity of it is unknown at the time but it's still there if one chooses to simply disable misfire detection and not solve the root problem.

I've wondered if this CPS error is the reason that I have to pull so much more timing in the 4500rpm area at mid-loads for shifts than needs to be pulled for a steady state pull through the same range. I realize that charge air temps are hotter after a shift than at the first part of the pull but I think I've already adequately compensated for that, especially when running E85. I notice significant RPM oscillations as the clutch re-engages but I don't know how much the timing might be off due to that.

[Danmark@VFF700singleturbo]

Originally Posted by shiv@vishnu

We suggest a clutch/lw flywheel to every customer who purchases a single turbo kit. All 10+ 6mt single turbo kit installs we have done in-house get just this. Which is why we have not seen the misfire problem before these 3 customer-installed kits were run with stock flywheel. We always, from day 1, publicaly stated that an upgraded clutch was necessary. Now we will be extending that to flywheel as well. You seem like you have an axe to grind. Get over it. No one cares.

Shiv.

I bought VFF700 single turbo kit for my E92 MT, and clutch from HPF stage 2, so I had a bit of a problem after your information with misfire.
HPF has thankfully been nice and exchange the clutch to Spec 2+ and flywheel. Good I had not installed it.!
Looking forward to get it all up and running, so I can be the first to have a 335 single turbo VFF700 car in Europe.

Jens.

[Wedge1967]

Originally Posted by Danmark@VFF700singleturbo

Shiv.

I bought VFF700 single turbo kit for my E92 MT, and clutch from HPF stage 2, so I had a bit of a problem after your information with misfire.
HPF has thankfully been nice and exchange the clutch to Spec 2+ and flywheel. Good I had not installed it.!
Looking forward to get it all up and running, so I can be the first to have a 335 single turbo VFF700 car in Europe.

Jens.

Hi Jens... Congrats... I've had the pleasure of riding in a couple of single turbo cars and you will not be disappointed. Look forward to seeing how things turn out. Please take pictures.

[Aridk]

Originally Posted by Danmark@VFF700singleturbo

Shiv.

I bought VFF700 single turbo kit for my E92 MT, and clutch from HPF stage 2, so I had a bit of a problem after your information with misfire.
HPF has thankfully been nice and exchange the clutch to Spec 2+ and flywheel. Good I had not installed it.!
Looking forward to get it all up and running, so I can be the first to have a 335 single turbo VFF700 car in Europe.

Jens.

Hej Jens

Just got very pleased to hear that there is a Vishnu/Fftec coming to Europ and of all places little Denmark,would love to see the beast when it´s up and running

Ps du skal lige introducere dig og din bil herinde:

http://www.e90post.com/forums/showthread.php?t=106243

[Rotorocious]

Quick question :
For Those experiencing the misfires, is it the same cylinder every time?
Or does it just say multiple cylinder misfires?


I'm just FBO but on a reused flywheel (60k) on my last clutch change. It's currently slipped after a hard launch. Anyway, a new noise I discovered is a rubber screeching noise. Much like the tire noise you may hear while driving on a epoxy floor.
I'm getting a cylinder 2 misfire that is consistent even with new plugs and swapping coils. Injectors are somewhat new and I can usually hear injectors start to fail. I'm wondering if this noise is consistent with those having a 6MT misfire. I'm suspecting my flywheel was machined incorrectly when putting the new clutch in and damaged. Although, it's ran fine for months after the clutch change and just now started acting up.

Video: I'm in first gear going over speed bumps, slowing to about 3-5 mph, having to hold the brake slightly. If you guys could try to replicate the noise, that would be awesome in helping diagnosing this DMFW issue.

[GeorgiaTech335coupe]

It doesn't really sound like that. It sounds like a typical misfire, whether it be injectors or something else.

[Rotorocious]

Originally Posted by GeorgiaTech335coupe

It doesn't really sound like that. It sounds like a typical misfire, whether it be injectors or something else.

I only get the misfire while at WOT, I know that type of noise. The noise in the video is the noise I hear after I cleared the codes and at a low mph. Curious if you misfiring guys hear anything like that at low mph (3-5 mph). I also hear it while slipping the clutch.
Just trying to find a common denominator

[GeorgiaTech335coupe]

Originally Posted by Rotorocious

I only get the misfire while at WOT, I know that type of noise. The noise in the video is the noise I hear after I cleared the codes and at a low mph. Curious if you misfiring guys hear anything like that at low mph (3-5 mph). I also hear it while slipping the clutch.
Just trying to find a common denominator

Hmm never really listened after. Usually shut the car off and turn it back on because the engine runs like crap after the misfire.

[Rotorocious]

Originally Posted by GeorgiaTech335coupe

Hmm never really listened after. Usually shut the car off and turn it back on because the engine runs like crap after the misfire.

For me the noise is constant whether it misfired or not. I'm pretty sure its a sign the rubber/springs in the flywheel worn out. Give it a try on your next drive.

[Gugs]

So Shiv-
whats the best flywheel solution that still provides vibration and noise dampening that the DMFW does without misfiring the problems- is single the only way?
They are loud :/