04-07-2010, 10:23 PM
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#41 (permalink)
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Master EcoModder
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No way, not buying that. 5% because the powertrain is more dampened? If anything there are tiny, but real, amounts of loss from a DMF when it converts mechanical input into heat loss in its springs.
I think this would be common knowledge if it was true. I like the lower idle speed theory though, that's a plausible area for improvement.
I replaced my stock DMF with a 21lb single mass when I went past the torque handling capacity of the stock setup (at 87k miles)... it is almost unnoticeable, clutch in to clutch out. Basically no rattling at all, just a change in pitch of the engine. No problem with vibration at idle, etc. That being said, my understanding is that the vast majority of TDIs live their lives with stock power (or less once clogged up a bit and driven slow) with the stock DMF surviving indefinitely - 200k + miles.
Basically the fuel systems on modern diesels are so sophisticated that idle smoothness, engine response, etc, would function fine with almost no flywheel mass at all. With a microprocessor in charge of precision fueling, each fuel injection event is a calculated dose.
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04-08-2010, 01:02 AM
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#42 (permalink)
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EV OR DIESEL
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I don't really know, but the pd car I drove with a lightweight flywheel (don't know how light) was very not smooth at idle, of course, the car may have had other issues.
Edit: this site has a decent theory on the fe increase http://www.murmini.com/articles/2007/04/01/dmf
essentially the vibration dampening of the flywheel allows lower speed operation (higher gear) and thus a fuel economy boost. Which I suppose would be of extra benifit with a super tall 6th.
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Last edited by dremd; 04-08-2010 at 01:12 AM..
Reason: Added theory
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04-08-2010, 05:40 AM
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#43 (permalink)
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The PRC.
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Quote:
Originally Posted by Deezler
I replaced my stock DMF with a 21lb single mass when I went past the torque handling capacity of the stock setup (at 87k miles)...
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What was your new torque limit ? I was told the standard clutch assembly is good for 300 lb/ft but internet wisdom at the time suggested any 'chipping' would need something more substantial. My target chipping was going to be a claimed 180hp but probably nearer 160 given no other changes. I didn't do it in the end.
Quote:
Originally Posted by Deezler
it is almost unnoticeable, clutch in to clutch out. Basically no rattling at all, just a change in pitch of the engine. No problem with vibration at idle, etc.
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This seems to vary from car to car - some people report no difference, some report a slight chatter and some much louder. I wonder if this is related to the make of clutch/flywheel - mine came as an uprated Sachs kit. My friend's SEAT Ibiza 150 has the same kit and is silent.
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[I]So long and thanks for all the fish.[/I]
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04-08-2010, 05:53 AM
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#44 (permalink)
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needs more cowbell
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I figure the extreme p&g eoc crowd would be the ones to benefit most from a light flywheel. If you can get the hang of launching, you would be throwing less energy away in accelerating the flywheel (you don't get to reclaim it usually), and you are always accelerating when you are putting gas in the engine in that scenario.
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WINDMILLS DO NOT WORK THAT WAY!!!
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04-08-2010, 10:51 PM
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#45 (permalink)
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EV OR DIESEL
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Quote:
Originally Posted by dcb
I figure the extreme p&g eoc crowd would be the ones to benefit most from a light flywheel.
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I am with you there!
I tend to keep my engine on except for longish lights, forced drive throughs (I love the horns for me to move up one spot), and the last bit of my journey.So I'm not sure that would help me much. I am however much much more aggressive the the key in non-turbocharged vehicles.
Good news, "all" of my bits are in, and the boots even came with CV joint grease.
I'm going to try and change my timing belt tomorrow (I actually ordered the timing belt set a week before the transmission, and it just showed up today). So after the timing belt I'll try and change the CV boot's / grease and hopefully get to the swap early next week.
More maintenance tidbits, the lab says the engine oil needs to go, 52,000 (at sample, 54,000 now) miles with out a drain isn't so bad though. My TBN took a dive, I'm guessing that if I had to add a little make up oil it would have stayed up, but whatever .
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04-09-2010, 02:34 AM
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#46 (permalink)
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(:
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I've long thought that my regular ol' low tech car would benefit from a heavier flywheel especially if regeared higher. Some of what that article says seems to confirm that.
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04-21-2010, 10:40 PM
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#47 (permalink)
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EV OR DIESEL
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Timing Belt Replaced!
Swine Flu contracted. (almost over it).
Maybe I need a doctor in my family. lol
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2016 Tesla Model X
2022 Sprinter
Gone 2012 Tesla Model S P85
Gone 2013 Nissan LEAF SV
2012 Nissan LEAF SV
6 speed ALH TDI Swapped in to a 2003 Jetta Wagon
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04-27-2010, 12:40 AM
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#48 (permalink)
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EV OR DIESEL
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Rebuilt the drive axles tonight.
Overall simple, the inner's you pry off the cap and pull the clip, and pull, the outer's you just hammer off.
It is driving me nuts having stock 5th, gear seems so short now lol.
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2016 Tesla Model X
2022 Sprinter
Gone 2012 Tesla Model S P85
Gone 2013 Nissan LEAF SV
2012 Nissan LEAF SV
6 speed ALH TDI Swapped in to a 2003 Jetta Wagon
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04-27-2010, 09:57 AM
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#49 (permalink)
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Master EcoModder
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Quote:
Originally Posted by dremd
It is driving me nuts having stock 5th, gear seems so short now lol.
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LOL I bet! After 1 year with the 0.658 ratio 5th gear in my TDI, I don't think I could ever go back.
Glad you are making some more progress.
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04-27-2010, 11:13 AM
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#50 (permalink)
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Master EcoModder
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Hey dremd,
Did you take that test ride yet? Been reading all the post's, your swap has been an interesting read. Looking forward to how it all works out, as sure as you are too!
Good luck,
Dave
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