I just picked up an 89 Civic Si and I went to install new Power Slot front rotors. When I jacked up the car I notice the rotors are different sizes. The Power Slot are 9.5" and the one that's on the car is 10".

Maybe the previous owner swap them?
What will I need to convert them back to Si spec?

 

here are some pictures

 

ugh do you mean 10.3 inch? no car that I can recall that is swappable came with 10" rotors, but I could be wrong.

 

Yeah it could be 10.3 inch. I didn't get a good measurement with the rotor still on the car.

 

It maybe DA front knuckles and rotors. Mine came with 99-00 Si front brakes.

 

I could be from a DA...I'm going to swap back the standard knuckles/rotors/calipers.

 

If I were you I'd swap the slotted rotors out for the Da ones and be done with it. Everyone could always use a better braking system but thats my .02 Good luck with whatever you decide to do.

 

agreed, bigger rotors=more braking surface. Even if you just had bigger rotors on your stock si calipers, it would still be an upgrade, although it wouldn't be a large improvement over stock, you would have better 60-0 times. You could find out what arms you have by looking at the part number and typing it in to a honda parts catalog.

 

From that picture...can anyone tell me what spindle/knuckle is that from?

 

No not really, they all look similar. Can you see any part numbers on the knuckle?

I would keep the bigger brake set up. What size MC do you have?

 

uh, you can put 14's on. as long as it's not the HX. you have to mod the caliper or use a spacer to make the HX fit. but any 14" 4x100 Honda rim should fit 99-00 Si brakes. even the 14x5 90-91 civic EX rims. how do i know, cause it worked for my GSR which run the same 10.3" rotor as your 99-00 si, and are the same as the 90-91 EX brakes.

 

^^^ Agreed! My 97 Integra had stock 14" rims and it was no problem.

 

Ah good info I tried the HX wheels, didn't know about the caliper mod. Thanks for the info!