A friend of mine bought am 87 Series 4 N/a that had a stuffed gearbox and tailshaft and has bought an S4 Turbo II gearbox, tailshaft & diff as a replacement, however there are a few things i'd like to know before assisting him with the conversion.

First of all is there any difference between the flywheel of the n/a and turbo II apart from the weight? If so will this need to be changed out (along with a new clutch) when we put the new gearbox in?

Second, are the half shafts that come out of the diff in the n/a different in anyway to the turbo II half shafts?

Is there anything else i should be aware of or tell him to buy before doing the conversion?

 

I just posted that info in this thread.
https://www.rx7club.com/new-member-r...rence-1052966/
stock flywheels are the same between series.
N/A and TII flywheel Clutches can't be interchanged,so that means TII flywheel use a TII clutch.(look at back of engine..Rip that off use that,,lol!).
You need the Starter for that Flywheel and ..so NO N/A starter for a TII trans or flywheel,it will not work.(and Vice versa)

Rotating assembly on engine needs to match.So stay in series.(S4 engine,s4 flywheel..NO S4 to S5)

you can put an s5 trans on an s4 engine..that is no problem.

The rest is whatever is up to you.
The tail spline of the trans only accepts whatever the Trans IS,..that means you can't put a N/A driveshaft into a TII trans..it will not fit..the diff flanges are not the same either between N/A and TII.
UNLESS you have the shaft is converted,either made or bought.(www.mazdatrix.com)

Diff's use the Shafts intended for them.N/A Half shafts to N/A diff...no mixing.

The Half shafts fit the car even if the rear subframe had a different setup before.
Like if it had N/A half shafts in the car..it will accept a TII half shaft..The splines at the wheel hub are the same.

 

Thanks!

Sorry i didn't check that thread but i wouldn't have thought a post on differentials would include that sort of information :-)