Going back to stock flywheel?

[jjewell]

I'm putting my 87 turbo trans back in tomorrow (finally taking out the t-5) and I was kicking around the idea of putting the stock flywheel back in. I have the fidanza light weight flywheel that i've been beating on for 4 years now. my thinking is all in dampening. if i put the stock flywheel back in I'll have a smoother running car correct? Yeah it won't rev as quickly, but should put more load on the engine to get the turbo to spool up a little harder. I'm just looking for some other thoughts on this.

[OR-Zman]

Why would the car run smoother? Due to the added weight? I don't see that as really making any sort of noticeable difference.

I'm not real sure about the stock flywheel creating more load that will help you spool up faster. Something about that just doesn't make sense to me but others can definitely speak to that better than I.

Unless there is something with the turbo spool thing I am completely missing I would stick with the Fidanza, especially if your wear plates are still in good shape. Even then, now is a good time to replace them if they are getting some wear.

[jjewell]

OR-Zman wrote: Why would the car run smoother? Due to the added weight? I don't see that as really making any sort of noticeable difference.

I'm not real sure about the stock flywheel creating more load that will help you spool up faster. Something about that just doesn't make sense to me but others can definitely speak to that better than I.

Unless there is something with the turbo spool thing I am completely missing I would stick with the Fidanza, especially if your wear plates are still in good shape. Even then, now is a good time to replace them if they are getting some wear.

well the thing about load on the engine came about with an oil change. before i went to the dyno for some tuning i did an oil change. i switch from my normal 20-50 to 10-30. when i took the car down the road i couldn't beleive what was happening. the car wouldn't boost anything over 18psi. a few minutes before when i took the car for a warm up run i had the boost set solid at 23psi. i changed the oil back to 20-50 and problem solved. i don't know why it happened but i figured the thicker oil put more load on the engine. these are the kinds of things that happen to me on a regular basis that no one can explain. :lol:

as far as smoother running, that would just come with more dampening from the weight of the flywheel.

[Az4u2c]

Well it would load the the engine more in neutral, so it might help with the launch. I would think the added inertia of the engine would make a bigger difference to you launch than the small amount of boost you gain. Once the car is in gear and going i really don't think it would help your spool time. I really don't think the end result would be beneficial, but I'm basing all this on inference so it really means nothing. If you decide to go back to stock, sell me your Fidenza, .

[NIVO]

i've had aluminum and stock flywheel and I can say this.

The car does rev quicker, I was getting better gas mileage with the lighter flywheel.

There always is the controversial, "should I use a ligthened flywheel on my turbo car" questions. I use them. But from lots of testing and seeing these kinds of things at the dyno shop I can say for some cars they are definitely worth it. Not on awd but definitely on a Z31. But that was my experience in where I can swap something out and test it on the dyno soon after.

Also there are other factors like an aluminum flywheel takes away some of the crankshafts stresses, most of it being on the main bearings, front and rear main seals.

As far as the turbo being loaded by the heavier flywheel? on dyno testing as you have found out the oil will make much more of a difference then going to a lighter flywheel, the flywheel is crank mass and the oil is not. thicker oil will rob some power.

Also remember that the turbo spooling is aided more by vehicle weight then the 4 lbs shaved off the flywheel.