Contour Enthusiasts Group Archives Forums Modifications Duratec Performance DMD adds HP? GRM says Yes. Discuss.

So that means another 11 hp to wheels! Excellent!!!

I don't have the article - were they only seeing increased hp numbers from extending the revable limits before valve float? If so, this is completely different from gaining hp from reduced friction and doesn't mean anything to Joe contour who isn't revving to valvetrain limits anyway.

Also, did the article talk about ignition timing scatter at all? I would think that at high rpm's you could possibly get better power from reduced scatter of the crank signal - but I have no clue how much that would buy you - if anything at all.

On the UDP thing - I would guess that an underdrive alternator pulley would have very marginal benefits as the load of the alternator is pretty much dependant on electrical draw - it may be spinning full speed but there will be very little resistance (ie free wheeling) when there is no electrical load. Now if you underdrive the fluid pumps (PS or even w/p) I would guess there'd be measurable gains from lower pumping speeds.

The DMD (nor UP Alt pulley for that matter) was never done as a performance mod. Both are reliability mods.

Also the fact you stated "the car runs off the battery & the alternator will NOT draw a load if the battery is fully charged" leads little credence to your technical ability.

The car's electrical system runs off the alternator and the alternator supplies current load as the car's electrical components demand it.

"The battery has 2 functions: It's main function is to start the engine & it's secondary function is as backup reserve for when demand levels exceed alternator output."

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2-3HP for bolting on some ring of rubber and steel on the end of the crank???? Come on! It was done for NVH, not durability or power.

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Where's your proof that the 2-3HP did NOT happen? (even though it did per the dyno & yes that's within it's margin of error, but that was already mentioned!)
Where's your undisputable proof that a DMD will not increase engine reliability?

Just going off the proven physic's facts alone showing it reducing destructive second mode vibrations should be proof enough that it's helping in the longevity department. Especially on an engine with a known problem in this area!

Again nobody said to install a DMD to make massive power gains. It is just an added benefit that the significant decrease in torsional bending and crank whip can equate to less parasitic drag placed on the rotating assembly and therefore make more power in the process.

Either way, I ordered one from Bill Jenkins earlier today, total, it's bout $58 or so, includes shipping, etc.

Is it recommended that I buy any other new parts along with the DMD, or can it go in by itself and be fine?

It would probably be a good time to change your serpentine belt. I got a Gatorback for $17 at Murray's.

Don't forget a new bolt.

Might as well change the seal as well, while you got the pulley off.

DemonSVT: You are missing the point. Whether the electrical load is coming straight from the alternator, or more indirectly from the battery/alternator system is irrelevant. You are splitting hairs. The load is the load.

The electrical load demanded at the alternator is what I mentioned. Going to a smaller pulley will not reduce the demanded load.

No - I can't prove that some test somewhere did not show a 2-3HP improvement. But I also can't prove that it lowered the price of tea in China at the same time. I know many of the Duratec development engineers and I know why the DMD was used - for NVH only. NOTHING repeat NOTHING to do with durability or power gains.

The physics are bolting a mass of rubber and steel on a crank and expecting even a tiny power gain do not add up.

Crank twist due to harmonics are measured in the few micron range. This will not effect the lubrication regime of the plain babbit shells, that have operating clearances in the 20-45 micron range.

You will get a lot of resistance to this from most people here. I used to argue that I beleived the same thing, but since I really don't have any data to support my beliefs I gave up talking about.

I know "procyon" is pretty knowledgable and he's stated he thinks DMD is probably only NVH as well - but like I said be prepared for a lot of resistance to the idea.