Turbo 2 Engine with NA flywheel/drivetrain longevity
 

Good morning Everyone,
Its been a while. Recently had my FC vert posted for sale and received an Email asking

"Curious how you are running the turbo flywheel on the NA transmission... I hope you did not use the NA flywheel on the turbo rotors. How are you running NA gear on this turbo motor. Do tell, I may be interested in the motor and turbo stuff. "
I replied with saying its the NA flywheel on the Turbo engine, and that yoiu could search it alot of guys are doing it, i had turbo 2 drivetrain that i was going to install so damaging the NA drivetrain was of no concern to me blah blah blah. and his response.

"oh man, yeah I have seen the write ups and I know why they are all without the cars now. I also watched a couple idiots around me do it. That motor is garbage, I promise if it was opened it will have serious grooves in the housings. Never rev it lol. If you end up taking it out and apart and the rotors are in good shape I would still be interested in purchasing all the turbo stuff. I have to pass otherwise, it is toast. "

Well i responding with "bro you should search your name and rx7 not good" guys got a lot of threads on here for being a scammer, THANKS RX7club for making that public! But my question is will running the NA flywheel potential damage to turbo engine, or is this guy trying to scam me outta my ride?? Engine builders have you seen any damage to turbo 2 engines from the NA drivetrain?? i could see if you blew up the drivetrain potentially causing damage but I havn't had that concern. Does the turbo 2 flywheel weight differ from the NA? its all manual so theres no counterweights.
Thanks for any help guys! greatly appreciated

As long as the n/a flywheel matches the series of TII engine it is on everything is fine. It's the n/a drivetrain that's said not to hold up on converted cars. There are counterweights on manual cars. The front one is the same between auto and manual. The rear one is made into the stock flywheel on a manual car, hence why you must use the proper series flywheel for the engine. Now if the wrong flywheel is used it would be unbalanced, Maybe that is where said grooves would com from.

S4 turbo 2 with S4 NA drive train. Thanks Dak for the info!

Some more information i've dug up the s4 NA flywheel weighs 30lbs, the s4 turbo flywheel weighs... 30lbs. Though the balance may be different looking at images people run light weight flywheels which im sure are not engineered as well as mazda did. The s5 NA flywheel weighs 21lbs, and the s5 turbo flywheel weighs 35lbs, this would be more concerning. Id love to hear some real time feedback from anyone running a s4 turbo with s4 na drivetrain or s5 turbo and s5 na drivetrain or vise versa. Thanks

Not sure where your info came from but according to Mazdatrix https://www.mazdatrix.com/identifyin...-of-flywheels/ the S4 n/a is 24lbs. and the S4 turbo is 27lbs. The S5 n/a is 21lbs. and the S5 turbo is 23lbs.
The light weight flywheels do not have the counterweight built into them like the stock one. They use the counterweight from the automatic transmission equipped cars of the appropriate series, thus making them universal. Meaning a lightweight n/a flywheel fits all n/a's and a turbo one fits all turbo engines. Also the actual reduction in inertia is greater because the lightweight ones don't have the thick ring around the outside edge like the stock one. As for the engineering it's not an apple to oranges comparison. Mazda designed it for a balance between comfort and performance I'm sure. The aftermarket ones are for performance and take some getting used to. I like mine but everyone may not. Especially the aluminum ones.

Don't the turbo rotors and NA rotors weigh different?

Weights are the same within each series I believe. Either way both use the same rear counterweight per series.

@Dak im gonna look into the weights of rotors im sure its on here somewhere ,actually....i have some t2 rotors(i believe s4), and at least one s4 NA rotor// my brother stole the other as home decor lol... dont know if he still has it that was 15 years back, ill try to bring them into work and weigh them out see how close it is.. The set up that was said to cause problems was using a fd flywheel which from the site you provided is only 20lbs.

I would think the weights should be close as there is only one rear counter weight for the S4. I had heard you can use a FD flywheel on a S5. That may be because all 89-95 use the same rear counter weight. If someone used a FD flywheel on a S4 they would have problems.

Are turbo flywheels counterweighted the same as NA's? I know they are not interchangeable.

They are. It's the diameter that is different.