f20c engine conversion
I think 17 will be big on an na even with flares.
But tire selection for 17 is much bigger, so go with what you know.
I'd run something like 16x9 with Nothing less than 275 in the rear
But tire selection for 17 is much bigger, so go with what you know.
I'd run something like 16x9 with Nothing less than 275 in the rear
If you really wanna get creative run a butt plug through your hymen and staple it to your tire pressure monitoring system (2x4some? something weird like that)
I appreciate that the tire selection is better in the 17" range, however, 17's look quite terrible on NA miatas.
Toyo has 3 tires (the typical RA series stuff) in a reasonably sized 16 255 50 if your hell bent on going larger than 15 225.
-Zach
Toyo has 3 tires (the typical RA series stuff) in a reasonably sized 16 255 50 if your hell bent on going larger than 15 225.
-Zach


Without flares, you are absolutely right 17's are way to big. However, I will be running AWR flares. The car above is on 18's under AWR flares and it looks really nice IMO. 1 inch smaller wheel and a little more sidewall and the look would be perfect. And yes, I am hell bent on going bigger than 225, unless Im on r comps there is no way 225's will hold the power I am making.
Without flares, you are absolutely right 17's are way to big. However, I will be running AWR flares. The car above is on 18's under AWR flares and it looks really nice IMO. 1 inch smaller wheel and a little more sidewall and the look would be perfect. And yes, I am hell bent on going bigger than 225, unless Im on r comps there is no way 225's will hold the power I am making.
17x8-8.5 (or more*) +30 to +40 should be good fitment...or lower offset (*depending on the flares). Toyo has the R1R in 245-35/17 which would be a great tire without having some crazy tall diameter. From there, you go to 275-40/17 which is about 1.75" taller...and that's a big difference. You'll want to stay between 23" and 24.5" diameter.
Here is a NB with 18"s running 285-35/18 (24.8"-ish tire diameter) with a NOPRO widebody kit. In this case, 18"s don't really look all that out of place.

And since you're going to need some brakes to slow that beast down...with the 17"s you'll be able to fit the Brembo GT kit I've had up for sale lol (shameful plug...don't take it too seriously).
Last edited by Doppelgänger; Dec 3, 2010 at 06:16 PM.
Pulled my plugs for a look, roughly 1000 miles since the car got tuned. The plugs look good, inspection of the piston crowns with a borescope showed nothing unusual. Im not sure what is on plug #1 any ideas, it is deffinately not aluminum. Any ideas??






If that is white ash that wipes off easily I would guess an oil control problem in #1. How did the piston look on #1 vs the others? If it was really rich you might see a washed out area in the carbon? Doesn't remind me of rich though, more like oil.
Could your PCV system be venting some oil and most of it going to #1 due to a manifold design?
Could your PCV system be venting some oil and most of it going to #1 due to a manifold design?
Very nice catch. This engine had 10,000 miles on it when I did the conversion, when I pulled the plugs to do a compression test they came out easy. I drove the car roughly 6k street and another 250 track miles. Before the turbo project was started. When I pulled the plugs to go to the colder heat range they didn't come out nice. There was resistance on the threads...enough to cause concern; though I am pretty ---- about this engine and build. I did some research and then decided to put just a dram on each plug. The first few threads were left bare. I can not over emphasize how little I used as I wanted to make sure nothing got down to the cylinders.
As a side note the plugs came out like butter, no concern about galled threads now. Plugs were reinstalled dry.
I searched reading plugs and ended up at a ngk site. They had a ton of different plugs shown. This plug falls into the cold/rich category Since I drive like an old grandpa most of the time I am okay with what I am seeing with the plugs.
PCV is capped of just using the breathers. F20's are know for their love of oil, it's possible that it is an oil control issue but I doubt it, The engine sues no more oil now that oil than it did NA, roughly 1/3 quart/1000 miles.
As a side note the plugs came out like butter, no concern about galled threads now. Plugs were reinstalled dry.
I searched reading plugs and ended up at a ngk site. They had a ton of different plugs shown. This plug falls into the cold/rich category Since I drive like an old grandpa most of the time I am okay with what I am seeing with the plugs.
If that is white ash that wipes off easily I would guess an oil control problem in #1. How did the piston look on #1 vs the others? If it was really rich you might see a washed out area in the carbon? Doesn't remind me of rich though, more like oil.
Could your PCV system be venting some oil and most of it going to #1 due to a manifold design?
Could your PCV system be venting some oil and most of it going to #1 due to a manifold design?
I think I needs more POWER!!! 
60 degree day, I took the hot rod down to PPIR (Pikes Peak International Raceway) to drive the SM and shake off some rust and couldn't resist fooling around just a little bit.

60 degree day, I took the hot rod down to PPIR (Pikes Peak International Raceway) to drive the SM and shake off some rust and couldn't resist fooling around just a little bit.










