Changing Diff Ratio in SP

roshmx5 · Postby **roshmx5** » Sat Mar 18, 2017 3:32 pm

Has anybody done this and their opinions. Just went in a friends NC with a 4.3 fitted and the torque was great.
Your advice would be appreciated.

smy0003 · Postby **smy0003** » Sat Mar 18, 2017 5:23 pm

NC has an NA 2L engine and different gear ratios, you can't compare final drives between your car and his/hers. The Americans pay a lot of money to source 3.6 diffs (what you have) they suit the turbo torque nicely.

The American · Postby **The American** » Sat Mar 18, 2017 5:40 pm

If you have an SP, I can't imagine wanting less than 3.6. I already find first gear is too short.

Maybe you need more power!

roshmx5 · Postby **roshmx5** » Sat Mar 18, 2017 5:52 pm

Thanks so much guys, really appreciate it. Sorry I have so many questions I am new to the MX5 scene.

BadBong · Postby **BadBong** » Sun Mar 19, 2017 12:13 am

Rosh, I've got an SP and I've dríven it with every diff ratio available.

On stock power, I would suggest that you change it to 4.1 LSD diff.

If you ever get more power, I would suggest that you go back to a 3.6.

4.3 is just too short (unless you really like to change gears...)

roshmx5 · Postby **roshmx5** » Sun Mar 19, 2017 12:52 pm

Thanks mate, I will be keeping stock power, glad to hear from someone that has done this. Great hat you have tried a few different diffs. Much appreciated.

Tezzax5 · Postby **Tezzax5** » Sun Mar 19, 2017 6:02 pm

For what it's worth I've changed mine to a 3.9 torsen.... Helps keep the revs sensible for highway cruising. Don't forget to change the speedo sensor if you decide to change ratios.