Ok... I have an 89 civic dx hatchback with an d16a6 and an si tranny swap. I also have a stage 1 act clutch with a street light flywheel, Aem cold air intake, and 2.5 inch custom exhaust. And it seems like the speedometer is off. By about 5 miles an hour. I am still using a cable type transmission and everything else seems fine. So anyone got ideas?

 

are you using the correct size tires?

 

let me guess... since I am using the dx 13 inch rims it may cause the spedometer to be off...

 

Wheel size is irrelevant (unless way too big). Tire size is what matters for speedometer / odometer accuracy.

 

ok that is weird. I have p175/65R13 I think.

 

It "feels" off or you know because you have checked it against something thats known good?

 

tires are too small,that is why your speedometer is off.

 

are u sure for that??

 

its your tire size
stock si tire size is 185/60-14
which is 23.06 in outside dia.

your tire size is 22.2 outside dia.

which is .86 in. different outside dia.
industry standard is difference of .5 of an inch considered "safe"
and will not throw your speedo off.

closest is a 175/70-13 at 23 in outside dia.
also a 185/70-13 at 23.5 in. outside dia. can be used
also keep in mind the speed rating of the tire is recomended to be "h" or higher