Got a track related question? I'll try to answer.

[TommyC]

Originally Posted by CSG Mike

Negative Batman.

Check out the load ratings on the tires you run. Most 225/45/17 and 255/40/17 tires in the EHP category are assumed to be driven hard, and have a stiffer sidewall than their counterparts.

It depends on the tire. Some tires like the Direzza ZII don't vary much, but a Toyo R888 does have an XL rating for load, which yes I could definitely see making a difference.

[TommyC]

Originally Posted by Fish Eagle

I've run both sizes quite a lot on track, and I prefer 225/45R17 - got better feel, and quicker.

What is your preferred tire in the 225?

[Fish Eagle]

Originally Posted by TommyC

What is your preferred tire in the 225?

Bridgestone RE-11S

[Keenercarguy]

@CSG Mike sorry I ask so many questions but:
Which fluid should I run on a daily driven BRZ that will also see a few track days per year? Motul RBF600 or Motul 5.1?
(The rotors are stock resurfaced and the pads will be switched between Carbotech XP8's and Carbotech 1521's.)
OH and how many liters of fluid does it take to flush the system?
Hi I'm a noob.

[Uplink]

Originally Posted by Keenercarguy

@CSG Mike sorry I ask so many questions but:
Which fluid should I run on a daily driven BRZ that will also see a few track days per year? Motul RBF600 or Motul 5.1?
(The rotors are stock resurfaced and the pads will be switched between Carbotech XP8's and Carbotech 1521's.)
OH and how many liters of fluid does it take to flush the system?
Hi I'm a noob.

I used to run ATE Super Blue (helped with identifying changed fluid by color) but when that went away changed to Castrol SRF and it has worked extremely well. Solid on the street, no boiling on the track.

[CSG Mike]

Originally Posted by Keenercarguy

@CSG Mike sorry I ask so many questions but:
Which fluid should I run on a daily driven BRZ that will also see a few track days per year? Motul RBF600 or Motul 5.1?
(The rotors are stock resurfaced and the pads will be switched between Carbotech XP8's and Carbotech 1521's.)
OH and how many liters of fluid does it take to flush the system?
Hi I'm a noob.

Rbf600 should be perfect for you.

2x 500mL for the initial flush, 1x 500mL for subsequent bleeds.

[wrbrz?]

Originally Posted by CSG Mike

I don't know if there is a PID for the fuel pump voltage, but it is variable depending on the fuel demand of the engine.

The thing here is you're WOT as you're coming out of the corner, not after you're straight, and the fuel delivery is fine for a bit before it briefly sputters, and then resumes.

I want to know why the fuel pressure momentarily drops. The rest of the log indicates that combustion is still happening, so it means there's a cut in the fuel delivery, and picking up air on a stock pump at 75% tank is not very likely, given where the actual pickups are.

I know it looks like fuel delivery resumes there (based on the fuel rail pressure), but I definitely didn't coast down the straight for the fun of it.
I tried to resume accelerating and gave up when there was no power.

[ka-t_240]

Trying to loose points for NASA TTD.


245 RE-71R or 225 Maxxis RC1? Would free up 4 points to go to the 225, and I think the RC1 will have more grip/last longer.

[Uplink]

Originally Posted by ka-t_240

Trying to loose points for NASA TTD.


245 RE-71R or 225 Maxxis RC1? Would free up 4 points to go to the 225, and I think the RC1 will have more grip/last longer.

Is there a cutoff for points by the treadwear? The RC1's are more of a true R-comp tire with a 100tw while the RE-71's are more of a street compound cheater tire (see also RS3's & Z2's) with 200tw to fit SCCA's requirements.

The RC1's will have much better grip at the expense of lifespan. The flip side too is, the RC1's will be terrible in the wet by comparison while the RE-71's could be used in any conditions.

If you are looking for ultimate dry grip, the RC1's will probably be the way to go. Better response, less rotating mass and the compound will more than make up for the contact patch size difference.

[Pat]

I wonder what the weight difference is.

[Uplink]

Originally Posted by Pat

I wonder what the weight difference is.

Maxxis doesn't list weights but according to Tire Rack the RE71's in a 245/40-17 are 23lbs. As a point of reference, in a 225/45-75 the RE71's still list as 23lbs and stock Primacy HP's are 22lbs. Even if it's a sub pound difference, multiply it by four and calculate it as rotating mass. Every little bit helps.

[redlined600]

While it doesn't really help you, I wonder if the hot setup is. E85 + 205 a7 ?

[ka-t_240]

Originally Posted by redlined600

While it doesn't really help you, I wonder if the hot setup is. E85 + 205 a7 ?

Depends on if you can make the points work with how many points Hoosiers are with having suspension and exhaust.

[ka-t_240]

Originally Posted by Uplink

Maxxis doesn't list weights but according to Tire Rack the RE71's in a 245/40-17 are 23lbs. As a point of reference, in a 225/45-75 the RE71's still list as 23lbs and stock Primacy HP's are 22lbs. Even if it's a sub pound difference, multiply it by four and calculate it as rotating mass. Every little bit helps.

I have a connection at Maxxis, I'm almost positive can get weights. Either way, my 17x9 rpf1 and re71 is lighter than the OEM combo. I would probably find some 17x8 rpf1s for the maxxis.


So if it rains, how bad would it be to swap to my RE71s in a larger size? Pretty sure you can only go down, correct?