fivehundredton

Pat can you comment on why a little bit lighter flywheel might not help with shock loading the drive train at this point? It seems to me that as far as the drive line is concerned, the flywheel is way more massive at the rpm range you're using.

aidandj

iTrader: (5)

Heavy flywheel dampens the shock loads.

fivehundredton

Dampens power pulses when cylinders fire, you mean? I'm talking about when that unforgiving clutch grabs the flywheel. More mass because upper rpm's.

good2go

iTrader: (2)

So by that logic**, wouldn't you theoretically then be preferring to bend a rod instead of an axle?


**assuming it's true

fivehundredton

He's not in the stock rpm range anymore.

good2go

iTrader: (2)

Granted.

But you are still implying that it is better to cause the engine to absorb the shock (i.e. momentarily "pause") instead of the subsequent drive train parts. That sounds like a sure fire rod destructor to me.

fivehundredton

No. I think it's engine load and rpm related. If I make 300hp at 6500 and I road race or autox with wot at 3000-6000 a lighter flywheel would probably hurt. A lighter flywheel seems much heavier at higher revs.

Joe Perez

iTrader: (8)

18psi

iTrader: (76)

lol

patsmx5

iTrader: (16)

Heavy flywheel dampens the torque pulses from engine and is required for reliability of the transmission, so it's staying.

To reduce shock loading on the entire drivetrain during shifting, I need to reduce engine power to almost nothing during gear changes. Like this. There is no visible RPM bounce after the clutch is out on this shift. And I run zero smoothing on my RPM trace (and almost every sensor really since that can mask problems).

fivehundredton

Thanks. I was really more curious about my logic.

Shortpersonbk

do we have some 140mph traps yet?

patsmx5

iTrader: (16)

No. I'm getting it to run on the stock ECU for fueling when out of boost right now.

shuiend

iTrader: (24)

Any updates on this thing? Get it on a dyno yet?

patsmx5

iTrader: (16)

Just driving and enjoying it. Since it is a street car, I want it to pass emissions all the time, so I'm working on making it do that with the turbo setup. Actually making very good progress but it's not finished.

I'll post a more substantial update once I've accomplished this emissions goal.

Stealth97

iTrader: (5)

And I can't pass emissions with less than half the HP. Damn you turbo people

patsmx5

iTrader: (16)

Having a turbo doesn't make it much easier to pass emissions, in fact that adds more crap to deal with (though different crap than a high power NA build I admit). There's several things I'm having to deal with right now that a NA build wouldn't have problems with.

Also, the list of cars that pass emissions/OBDII codes all the time on there turbo miata is an extremely, extremely small list, and all of those setups are not able to make high power due to the limitations of their engine management. I'm going to fix this.

hi_im_sean

iTrader: (3)

dooo da do da do
https://www.miataturbo.net/suspensio...trength-83376/

fivehundredton

No ****. Put it this way then. If that flywheel is one particle heavier than it needs to be for trans health then the POTENTIAL shock load to the drive train will be greater with less than PERFECT rev matched shifts. And longer delay between shifts. The flywheel may be too light now for all I know. I ask. Ya'll maths it.

sixshooter

iTrader: (12)

Mathisses -
Stock transmission + stock power × 4 / flywheel weight = (little toofs coming off gears)