Big SC's Big SC FRS Build

[Castillo817]

$315 shipped ($125 per tire) and $65 to ship them.

Sounds like a good deal, but I have 17x9s. Wonder if that will be too much of a stretch with those tires?

 

[Redline]

Sounds like a good deal, but I have 17x9s. Wonder if that will be too much of a stretch with those tires?

9" are great for 245s. Some would argue that's in the ideal range for them, actually. If your rims aren't wide enough for the tires, handling is negatively impacted. I really should be running more than 8" for my 245s. Ask @phate for a much better explanation.

 

[CorkSport - Derrick]

Nitto says it will work, from their webpage.

Approved Rim (Measuring Rim) Width (In.) 7.5-(8.0)-9.0 1521 @ 51

Looks like 8 inch is recommend and 9 is doable.

 

[Redline]

Nitto says it will work, from their webpage.

Approved Rim (Measuring Rim) Width (In.) 7.5-(8.0)-9.0 1521 @ 51

Looks like 8 inch is recommend and 9 is doable.

Good info from the manufacturer. Gotta remember that not all 245s are created equal, so I'd definitely listen to Nitto.

 

[VTMongoose]

Agree with others. Tire sizing is pretty nebulous and they should fit fine. Just be aware you'll have some speedo error because they're a 45 ratio instead of a 40. Personally I use a 235/45/17 for my track/autocross setup. Mine have about a 2 MPH error and I'm used to it by now. Just need to use a GPS to estimate your speed error and keep an eye when you're cruising on the highway (make sure not to exceed the speed limit). The advantage of a 45 ratio is cost. They are slightly cheaper than an equivalent 40 ratio.

 

[Redline]

Agree with others. Tire sizing is pretty nebulous and they should fit fine. Just be aware you'll have some speedo error because they're a 45 ratio instead of a 40. Personally I use a 235/45/17 for my track/autocross setup. Mine have about a 2 MPH error and I'm used to it by now. Just need to use a GPS to estimate your speed error and keep an eye when you're cruising on the highway (make sure not to exceed the speed limit). The advantage of a 45 ratio is cost. They are slightly cheaper than an equivalent 40 ratio.

This assumes the ratio is correct for Speed 3s in the first place. I wonder if the engineers made adjustments for Speed 3s. For all we know, only stock Mazda 3s are right-on (and they run a different tire size)... Anyone know for sure?

 

[VTMongoose]

Uhhh...right, so, remember how I was talking about comparing your speedo speed to GPS speed? The stock tire size and rims are bang-on, at least in my car.

 

[Redline]

Uhhh...right, so, remember how I was talking about comparing your speedo speed to GPS speed? The stock tire size and rims are bang-on, at least in my car.

Good to know. But I wonder how accurate GPS speed is? I think the most accurate test would be one of the various types that police use, but I'm not sure. I also wonder if changing gear and/or final drive ratios have an impact in ATR. I'm guessing they don't; I think the speedo is mechanical. It would be nice, though. Speaking of which, I really wish we had a way of fixing our tachometers. They already read ~400rpm high at redline.

Anyways, I won't muck up this thread more with this digression.

 

[Big SC]

free bumps anyway.

 

[Big SC]

300/300ish final numbers.
[doublepost=1473454613][/doublepost]might switch over to a turbo kit eventually though.

 

[Redline]

300/300ish final numbers.
[doublepost=1473454613][/doublepost]might switch over to a turbo kit eventually though.

FWIH, turbos are much better in terms of engine longevity because superchargers cause forces on engine bearings that cause premature wear.

 

[CorkSport - Derrick]

only 300? Sanda Panda, I was thinking you were supposed to be the 350 range.

 

[Big SC]

yeah well looks like turbo might be in my future. FWIW the last 100 hp could be had with more compression than 10:1

 

[Big SC]

first page for dyno chart

 

[Big SC]

The replacement is more displacement:

 

[CorkSport - Derrick]

Trade it in?

 

[Big SC]

yeah, got just enough.

 

[Big SC]

Taken with a Galaxy S7 edge.

 

[Big SC]

sooo this just happened:
https://minneapolis.craigslist.org/hnp/ctd/6046994844.html

 

[Redline]

See the receipts for all the work, do a compression/leakdown test, etc? That's a ton of mods; buying modded cars can either be very good or very bad depending on your due diligence....