Final BRZ Goal
 

Hi guys, can you chime in on the goal I have for my car?

2014 BRZ Limited A/T - Manila, Philippines
- DD for only 15km but in heavy crawling traffic
- Once a month highway trips 50kms only, highway speed limit is only 100kph or 62 mph

I want the car to be perkier but retain all oem comfort in sound and feel, avoiding any ECU adjustments, and no suspension changes because road bumps and ramps here are high.

Plan:
1. Lightweight wheel and hankook ventus - I plan to stick with stock diameter so maybe Enkei rpf01 with 17x7.5 +48 and 215/45/17 tires
2. FD 4.56 cusco or 4.88 weir


Thats pretty much all really! My only question is 4.56 or 4.88 on the FD. Not sure which is best based on what i described as my driving conditions. Im thinking 4.88 because ill never see any speed above 70mph anyway and i dont track much. But will 4.88 be too rough and jerky in city traffic? Or any other noise? Or will the 4.56 be not much of a diff from stock 4.10?



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Just keep in mind that lightweight wheels aren't as durable. I forget what you said the road conditions were a while back, but I don't recall hearing good things about them. Stock wheels aren't particularly heavy but should be able to take a beating.

Also, 215s on a 7.5 are a bit stretched I think. Might want to go up to 225s if you get 7.5 width wheel.

+2 on the 225 tire on a 7.5" wheel.

Will that affect my speedo and odometer?


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Yep, sure will. 225/45 tires are just slightly larger than stock the gearing is increased and your speedometer will be off by 1MPG in your case you guys use Kph there. As long as you dont use heavy wheels i doubt you will feel much of a difference.

Technically a 225/45 would be a larger diameter. I think a 225/35 might be a bit smaller diameter. The changes we are talking about are within 5mm by my estimate. You can do the math, but I think the difference is negligible.

I'd personally stick with 215s. 215s is hardly stretching, but the slight stretch would help stiffen the sidewall, which could contribute to helping the car feel "perkier" as the OP stated he wanted.

Plus, I'd end up upgrading the tires to something better, like P4S, which runs a touch wide... But that's just me.

Gonna chime in here cause i'm running the ventus RS3's right now and you were speaking about sound, the RS3's aren't the quietest tires, there is a little more road noise then stock so keep that in mind as well

How will you hear the new road noise over the regular road noise?

It really depends on the tire, tires are all different widths. Frankly the stock tires really shine on 7.5's.

Did you see this thread?
http://www.ft86club.com/forums/showthread.php?t=27647
Stock MT engines run at ~3000 rpm while cruise around 70mph. With increased FD, it will be proportionally higher than 3300 rpm at 70mph. Do you want that? To me, 3000 rpm is already a bit high at cruise speed. I am not commenting on city driving since the drivers who like low-end torque will also like that rough/jerky ride. If you are one of them, that is what you want. Again, I prefer having the torque at high rpm just like the twins designed to be.

To be exact, your speedometer will show 1.44% lower speed with 225/45 compared to 215/45. But after 5/32" wear, it will be 0.17% lower. For reference, when your 215/45 tires wear out 5/32 inch, your speedometer will be 1.27% higher. As you see, your speedometer will be off when 215/45 is old but it will be off when 225/45 is new.