FX45copper,
I started this thread because the dyno really didn't show a gain, but the car pulled harder after the install.

There's a 20mph turn, service road to service road, I hit about 35mph. Half way through the turn, I start accelerate. There's 45mph sign, I normally pass it at 77-78 mph. After the pulley was installed, I can now pass the sign at 80-81mph.

Also my SLIP light flashes a lot more while the VDC is on.

 

dang, i wish i wrote down the webpage on how certain dyno setups can be so misleading and that most dynos will not accurately or cannot show changes despite certain mods done.... it was bmw and dinan (bmw specialty tuner)...

 

I see your sig and I don't think I named you as the respondant.

I think the back and forth has been pretty level and somewhat punchy for both sides of this argument. I'll be happy to not dispute what the "scientific facts" present in my current tone (as soon as we get some facts) if the naysayers are a tad less condescending. And I never claimed to understand anything except real world experience from having used the mod.

My point is still valid (for Munchee only) despite my lack of understanding how a lighter crank still goes the same speed as a heavier one.....If the person driving is susceptible to such placebo effects, fine, what is the effect for the person trying to imply or vicariously experience such effects through another persons experience without one experience of thier own....I call it guessing.

As for your UDP, Caleric, did you install it as one of or the first mod or after you built your car to what it is now? With all your mods it would seem difficult to measure by the seat of the pants if it was the last one you did.

And finally, I do understand every one of his threads...not agreeing with them is not that same as misunderstanding them. He hasn't said much that most HS educated could not comprehend. And your claims that, "I don't understand" are not based on anything related to natural science. He and you have far from taken the leap from that 8th grade textbook to the realm of empirical based support for his claim. Any independent reader here would have no better clue as to what the truth is after reading this thread than before reading it! There is no proof for either camp so until someone actually funds and settles the disputed results in a controlled environment, save the line about "actual science". There has been little science worth repeating here and none of it is based on any data from real world results. The wonderful formulae previously presented, may or may not apply and no one here has proven that they DO apply.

You see where this is going...everything is disputable excepts the results and while everyone second and third guesses no one has actual emprical results to chew on and wondering readers are still stuck pondering whether to believe it works or doesn't. If only everything could be solved in an internet thread.

 

This comment alone proves that you have absolutely no grasp of the argument. Further replies to this thread are a waste of time.

 

Yeah , I can understand placebo's but when I get in my car and try to launch like I usually did (3k rpm feather) , the rear end starts drifting to one side as a result of losing traction. This NEVER happened before I did the pulley install and also when Im in first gear at 3k rpm and I punch it my tires break loose for a few seconds, another thing that NEVER happened before the install. I dont care what formulas or statistics you have, the car is definately different with the pulley...hell , the CAI is a huge placebo because of the noise and I dont even notice it making any difference. As for the badmouthing thing, the majority of your posts are negative and secondly I didnt put out a dime for the pulley so I have no reason to justify money spent. I understand how you can get in the car and say "it feels faster" after an air intake because of the noise, but when the car breaks tires loose and the rear end drifts while launching (SOMETHING THAT NEVER HAPPENED BEFORE) I dont see how I could possibly say "thats normal , it must have been my oil change" You get 2 stock G's that run nose to nose and i'll pay for the pulley and we will see which one is faster. If the mod didnt do anything I woulda said so, i love my pulley , it goes to bat for me and I go to bat for it <3

 

Thanks God - maybe he means it!

Thanks to the reinvented sciences, mass no longer affects acceleration...what a fukin crock of pus and fluids

 

Yes, and I'm sure the decreased angular momentum of your engine assembly made it much easier to break the rear wheels loose while launching. Another excellent point. Not.

If you wanted to be scientific about it, you'd remove all variables from the experiment. We're just angularly accelerating an inertia, there's no need for the variabilities of different cars with slightly different engines, different temperatures before and after the crank install, etc. You would simply measure the acceleration versus time for the G35 engine in whatever gear you'd like to perform the experiment. Then rig up an apparatus to accelerate a single stock crank pulley by itself and measure how much power you had to apply versus RPM to match the acceleration rate of that of the G35. Now do the same for the lightened component, and subtract the two power curves to see how much power you've freed up with the lightened component. Here there would be no variability or error, other than that present in the measurement devices themselves.

But anyone familiar with such an experiment would realize that it is a waste of time. If you tell me the acceleration rate of a certain mass, I can very easily tell you how much force was required. This further reduces error, because we have even taken the measurement equipment out of the equation. And this is precisely what I've done with my simple article on the gains from a lightened crank pulley or flywheel.

More wasted breath I'm sure.

 

Yes, mass clearly no longer affects acceleration. Another great point by SixFive. Not.

 

This is a good point, though a tad misleading in this case. "Gains" from reductions in inertial loads only appear in transient. That is, you can't put out additional power to the wheels unless you're accelerating. In steady state, masses don't really matter (such as why your top speed isn't a function of your vehicle weight, but how long it takes to get there is). Certain dynos will hold your engine at certain RPM and measure steady-state load. You won't see any difference in power output with any lightened component in this case, since nothing is accelerating (unless additional crank resonances have an effect on sensor readings). However 99% of the dynos you encounter are inertial dynos, and work by measuring the rate of acceleration off a drum being spun up by your engine through the driveline. Here accelerations are occuring by definition, the rates of which are dependent on the inertia of the drum and your engine's power output. This isn't directly related to the acceleration of your car on the street (which is a function of the inertial load that the car's mass and other components have through the powertrain on the engine), and the shown "gains" apply only to that acceleration rate on the dyno.

 

Too lazy to read 5 pages of gossip. Get to the point.. you say the car pulls harder.. does that mean it is faster? Is it 1/4 proven?

 

I've never ran the car at the track, so I have no base line to compare it with. I was expecting the dyno to show my gains, didn't happen.

 

To tell you the truth, maybe the car losing traction was the result of the weather being cold. I have noticed since the weather got warmer it does not happen.

 

A lot of info in your post (way back there) MechEE - starting to make sense to me.

thx for taking the time to post it...

 

Thanks. I'm glad somebody gets it.

 

there was a looong thread about the positives/negatives of a UDP and most of the same people who are arguing here, argued in that same thread over a year ago. I have seen a dyno before/after from a UR UDP and the guy showed a 2-4hp gain. I will try and search for the dyno chart, but I am thinking the problem w/ all the old web images being blurred, might make the pics non 'viewable'.