Thank yall for the insight

 

How exactly on the SCT you get to see those parameters you mentioned on your ifrst post? Just wondering...

 

So has anyone adjusted these settings and noticed any difference in performance? I should add, without damaging your engine. I just had my SCT X3 out today loading a 87 Brenspeed Tune for a road trip and was wondering the same....

 

I would highly recommend not adjusting most of those parameters, other than revs per mile and gear ratio. The tune itself is set at the best recommended settings for your vehicle.

 

http://www.miata.net/garage/tirecalcold.html

http://www.1010tires.com/TireSizeCal...?action=submit

215/65R16 STOCK
8.464" WIDE
27.003" TALL
84.835" ROUND
747 REVS / MILE

235/55ZR17 STOCK
9.251" WIDE
27.177" TALL
85.379" ROUND
742 REVS / MILE

235/50R18 STOCK
9.251" WIDE
27.251" TALL
85.641" ROUND
740 REVS / MILE

245/50R18
9.645" WIDE
27.645" TALL
86.851" ROUND
729 REVS / MILE

255/50R18
10.039" WIDE
28.039" TALL
88.088" ROUND
719 REVS / MILE

265/50R18
10.433" WIDE
28.433" TALL
89.325" ROUND
709 REVS / MILE

245/45R18
9.645" WIDE
26.681" TALL
83.821" ROUND
755 REVS / MILE

255/45R18
10.039" WIDE
27.035" TALL
84.934" ROUND
746 REVS / MILE

265/45R18
10.433" WIDE
27.389" TALL
86.047" ROUND
736 REVS / MILE

255/40R18
10.039" WIDE
26.031" TALL
81.780" ROUND
774 REVS / MILE

265/40R18
10.433" WIDE
26.346" TALL
82.769" ROUND
765 REVS / MILE

275/40R18
10.826" WIDE
26.661" TALL
83.759" ROUND
756 REVS / MILE

26" = 81.681" ROUND = 776 REVS / MILE
27" = 84.823" ROUND = 747 REVS / MILE
28" = 87.965" ROUND = 720 REVS / MILE
29" = 91.106" ROUND = 695 REVS / MILE

 

Never adjust any paremeters unless your on a dyno and running air fuel gauges......good way to murder your engine

 

So since I have these tires on the front:
255/45R18
10.039" WIDE
27.035" TALL
84.934" ROUND
746 REVS / MILE

and these on the back:
275/40R18
10.826" WIDE
26.661" TALL
83.759" ROUND
756 REVS / MILE

What should my revs/mile be? Like maybe split the difference so like 751?

 

Yes I have adjusted some of my parameters, and I have not blown up my engine.
I can't recall all the changes I made, but I do remember retarding the low end timing a bit, which did perk it up a bit, and richening the WOT a little.

 

No go to the manufacturers web site and find the rev's for the model and size of the rear tires, then enter that number into your tuner.

 

Ok thanks. Just looked it up in Nitto's site. Gonna set it for the rear tires at 779 revs/mile