Dual Mass vs. Single Mass Flywheels, Advantages/Disadvantages??????????

[Paul Workman]

Originally Posted by alnukem

Paul, I tried studying on flywheel weight before....I thought I came up with the HP was mainly due to the way a dyno measures & not a "true" number, as if you had heavy wheels on your car & it dynos less with no difference in the engine. I do realize if you drop off weight it will accelerate faster.

You are correct. "Effective power": During acceleration, energy transfers to the mass of the drivetrain, and that left over goes to the wheels. By reducing the drivetrain mass, e.g., a lighter weight flywheel, the effective result is as tho the engine had more power. Actual crankshaft output, or "true" horsepower is not changed. Using a Fidanza flywheel will not increase power at the crank, or when pulling a load at a steady pace. Only when rpm is accelerating (or decelerating) will the effects of a massive flywheel be a factor.

[alnukem]

Thanks Paul....I'm still into "if Dick had 2 Rocks & Jane had 3 Rocks"!!!!!

I wonder where the sweet spot is, maybe one of Jerry's flywheels with a sprung hub?????? I have a factory DMF, so that's probably how I'll go.

[-=Jeff=-]

All I know is when I I had my 89 I had a Centerforce single mass flywheel it was almost as heavy as the DM Factory one. I swapped to a fidanza and I hated driving the car ever since. the technique for driving the car around town changed dramatically.

I did not realize Jerry had 18 and 22# SM flywheels, I would probably do a 22# and hope that the car does not completely change. but for now I will keep the DM.

When I bought this car I came to the realization that there will always be someone faster than me.. I am good with that, I now just enjoy driving the car

[5ABI VT]

What are the chances a lighter weight dual mass could be made to work? many cars use them these days

[LGAFF]

If anyone is looking for a replacement Dual Mass Flywheel, I just shipped three over to Power Torque systems. He is going to give them the once over, light resurface....

Two under 8K miles and no visible wear, one with 17K miles

[5ABI VT]

Here is how I look at it. If you put on a 40 lb back pack you are no stronger or weaker. But if you try and run with it on.. it will affect your acceleration !

[XfireZ51]

Originally Posted by 5ABI VT

Here is how I look at it. If you put on a 40 lb back pack you are no stronger or weaker. But if you try and run with it on.. it will affect your acceleration !

And conversely the more mass, the harder it is to stop or change direction. There's a reason race cars go for lightweight. Unlike =Jeff=, I preferred my
84 w the Fidanza and ZF-6 combination. Same is true w both ZRs.

[Locobob]

I think I preferred my old 20lb-ish LPE (McCloud?) flywheel over the Fidanza I have now. The abrupt speed at which the engine winds down when you get off the gas is a little much and kind of annoying during normal driving.

[XfireZ51]

Originally Posted by Locobob

I think I preferred my old 20lb-ish LPE (McCloud?) flywheel over the Fidanza I have now. The abrupt speed at which the engine winds down when you get off the gas is a little much and kind of annoying during normal driving.

LB,

That's easily addressed by slowing down the IAC.

[Paul Workman]

I guess I'm just lucky. I have very little rattle if any in neutral (evident by the video I linked to). Lee reminded me too that in addition to the 850 rpm idle, Accel injectors, new plugs, I also have a Centerforce, Camaro LT1 sprung hub (Centerforce # 381039 from Summit Racing).

I noticed a difference in technique when pulling away from a stop, i.e., a little more feathering perhaps than was needed with the heavier FW. But, after just a couple hours in traffic, I no longer notice it.

As for deceleration, maybe because mine is a 90 and typically is slow to return to idle (that was later "fixed" in subsequent calibrations) I can't say it has been a problem - decelerating to quickly*.

*I notice tho that when decelerating from speed, as in during the Mountain Run 2, the engine stalled - an old problem that seemed to return that had disappeared for a couple years. The stalling isn't the fault of the flywheel, I don't think. I rather suspect it might be something like oil in the MAP tube - which was an issue once when I first got the car in 2007.

I had already purchased the oil separator to address oil getting into the MAP and fouling the valves and combustion chambers. So, now that it has been installed, we'll see if that was the issue. However, the flywheel weight isn't a serious consideration, at this time.