Lighter rods/pistons mean less crankshaft counterweight.
So that means less rotational mass ? Because the counterweight offsets the rods ?
Lighter rods/pistons mean less crankshaft counterweight.
1st gear 2000 to 4000 rpm- engine #1 1634 rpm/sec........engine #2 1910 rpm/sec (276 rpm/sec difference)
1st gear 4000 to 6000 rpm- engine #1 1975 rpm/sec........engine #2 2217 rpm/sec (242 rpm/sec difference)
So that means less rotational mass ? Because the counterweight offsets the rods ?
Im interested in this subject as I am starting a 408 4sp project and need a flywheel... I am also considering a 3.09 1st as well and would like tto hear pro's and cons. I have my own theories but would like some practical input.
Maybe a new thread ?
I am not using an O.D. . Greeeeat I am picking up a 66 833 this weekend that should have the 3.09 and I have another 833 with std gearset
I am trying to build a "Suoer Sleeper" 69 340 Swinger... the only visual giveaway will be TTI step headers.cool
I am thinking of running 3.23s on the street and the 3.09 1st would work well It will..... just not sure how that would effect track performance if I toss a set of 3.91s in . Probably too low, more like 4.30s depending on the power-curve.
Will the torque mask the big ratio jump ? yes
So let me see if I understand this right;
If you recalculate the difference in rates to get an average,would that be (276 +242)2 = 259 average from 2000 to 6000? So say I have a streeter that hits 60 mph at 6000, at the top of first gear; and it takes 5 seconds, with the heavy flywheel. Are you saying that the lighter fw will get me there 259/6000 x 5=.21 seconds faster?
As I recall this was from a dead hook?
OK I can see this as useful on the track.
But how useful is this to me,a streeter, who will spend the first 4.999 seconds spinning?
What do I have to spend to make my streeter hook, by 2000rpm?
You see where I'm going with this right?
And since it was brought up...don't take the entire weight of the clutch assembly to figure percentage of change with FW weight UNLESS you are changing the weight of the other components.
A 15 pound FW has 50 percent less weight that a 30 pound wheel. If all you change is the FW that's how you figure percentage of change.
So are you saying an aluminum clutch will make the car more or less easy to drive on the street ? Which will be 98% of its use.
And to say a 440 won't notice a weight change in FW compared to a 340 is abject bullshit.
Here is what I am trying to understand. ... Doesn't the rotational mass of an 11" flywheel have a different effect than the reciprocating balanced assembly ? The crank has a center of about 5"s and the rods are not spinning they are "stroking" for lack of a better term...So the initial post about acceleration per sec. of 2 differently balanced motors is a little misleading.
The engine with Aluminum rods and far lighter bob weight is going to react differently than if just the flywheel itself was that much lighter...? Correct ? And the test was done from a roll where as a dragstrip launch is done with RPMs up then dropping clutch. In which case I would think the built up energy of the heavier flywheel would be a benefit assuming you had enough traction.
Thats my imbalanced thinking...lol
I also like the second gear "hit" of my heavy fw, and all the hits when I start splitting gears. If I were to lose that, that would take all the giggles out of shifting. The GV shifts under full power, just like an automatic, but the rpm drop is just 1500@ 6800.Makes a nice tire-chirp at 77 mph......