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

[ka-t_240]

Originally Posted by Uplink

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.

I have a couple friends with the RC1, they have been very impressed with the life. I have ~4.5 HPDE and about 10 autox days, and maybe 2k street miles on my RE71s and they are at half tread. Many people are talking 10-12 HPDE days on the RC1 with out issues.

[redlined600]

Originally Posted by ka-t_240

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

Anyone running tt-d care to comment?
A theoretical from scratch build
205 a7 15 pts
Shocks 4pts
Free mods including e85 with a custom tune
Gutted and ballast up to weight.

Sorry to take it a bit off topic though.

BTW once I start running tt-d I'll be in a similar boat to you due to my existing mods unless I swap back to stock suspension. Exhaust is a worthless points spend for the frs IMO.

[Blizzard]

Don't forget the Maxxis contingency program! Not the absolute fastest tire, but it is very forgiving and has a long life compared to similar tires.

[Uplink]

Originally Posted by ka-t_240

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?

Just to give you an idea, my 245/40-17 Z2's (listed on Tire Rack as 25lbs) on RPF1 17x8's with no tpms weigh in at 42lbs while my stock wheels/tires/tpms weigh 41.8lbs each.

If you're going 225, definitely don't mount them on the 9's.

As to swapping sizes, looking over the rules I found this:
"7) The following DOT-approved tires and those R-compound tires with a UTQG treadwear
rating over 40: BFG Rival S, Bridgestone RE071-R, Maxxis RC-1 (examples: Kumho V700,
Kumho V720, Michelin Pilot Sport Cup & MPS Cup 2, Nitto NT01, Pirelli PZero Corsa,
Toyo R888, Toyo RA-1, Yokahama A048, etc.) +6"

So you're looking at +6 regardless of which tire compound you select, then the sizing would follow this...
"10) The following tire sizes will be used as the base tire size for each Base Class for all
vehicles regardless of their OEM tire size(s) or their Final Competition Class. All
vehicles in a given base class may use this tire size (or smaller) without a points assessment:
TTB: 265mm, TTC: 255mm, TTD: 245mm, TTE: 235mm, TTF: 215mm,
TTG: 195mm, TTH: 175mm
Tire width points assessed or points credited are determined by the difference between the
width of the largest tire on the vehicle and the assigned base tire size as follows:
Equal to or greater than: 10mm +1, 20mm +4, 30mm +7, 40mm +10, 50mm +13,
60mm +16, 70mm +19, 80mm +22, 90mm +25, 100mm +28, 110mm +31
Equal to or less than: -10mm -1, -20mm -4, -30mm -7, -40mm -10"

Which means you wouldn't have a penalty for running 245 RE's in the wet since that is TTD base size but you should actually recoup 4 points when running the RC1's. Depending on what other mods you have you may want to run the 225 RC1's for point allocation alone but be aware if it's a wet day and you were at max points, you'll be over running 245 RE's when you lose the 4pt credit.

[Uplink]

Originally Posted by ka-t_240

I have a couple friends with the RC1, they have been very impressed with the life. I have ~4.5 HPDE and about 10 autox days, and maybe 2k street miles on my RE71s and they are at half tread. Many people are talking 10-12 HPDE days on the RC1 with out issues.

Wow, that seems like a LOT of time on the RC1's! My Z2's were rocks by then even though they had a ton of tread left (5-7/32nds) and most of my time was taking students out or helping them with lead/follow exercises so nowhere near 10/10ths.

[Uplink]

Originally Posted by redlined600

Anyone running tt-d care to comment?
A theoretical from scratch build
205 a7 15 pts
Shocks 4pts
Free mods including e85 with a custom tune
Gutted and ballast up to weight.

Sorry to take it a bit off topic though.

BTW once I start running tt-d I'll be in a similar boat to you due to my existing mods unless I swap back to stock suspension. Exhaust is a worthless points spend for the frs IMO.

That's the tricky part with a lot of race series, you have to build your car specifically to work the rules or you're at a disadvantage. It's really tough to build a car to your liking then make it competitive.

[redlined600]

Originally Posted by Uplink

That's the tricky part with a lot of race series, you have to build your car specifically to work the rules or you're at a disadvantage. It's really tough to build a car to your liking then make it competitive.

Oh, I know. I'm built to solo stx foremost but I kept everything to be scalable to a somewhat regionally competitive tt-d car in the future.
For now it makes a pretty good autox/track car.

[CSG Mike]

Originally Posted by wrbrz?

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.

Can you remind me what fuel pump you're on? Any fueling mods, other than your tune?

Are you tuned on Ecutek?

[CSG Mike]

Originally Posted by Uplink

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.

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.

The RE71R will have more grip, but last much, much less. Also, it will overheat faster on track.

Do you want a lot of seat time, or that one magic lap every session?

[CSG Mike]

Originally Posted by wrbrz?

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.

Perhaps you're tripping a failsafe of some sort built into your tune?

[wrbrz?]

Originally Posted by CSG Mike

Perhaps you're tripping a failsafe of some sort built into your tune?

Unless it's a very standard thing to include or somehow not removed from the stock tune, I doubt it.
Mainly because there are two other cars I know of (tuned by separate tuners) that have exactly the same problem at high fuel levels on E85.
I believe they are tuned with either brzedit or ecutek.

I have no fueling mods at all, am using the stock fuel pump and running an OFT tune.

[Keenercarguy]

Should I be worried about boiling my stock fluid while bedding I'm carbotech XP8's? I have RBF600 coming Tuesday but would like to bed the newly mounted track before changing fluids, since I need to drive to classes and work Monday.
I'm guessing i don't need to worry about it but I want to bed them in as best as I can on the street, so I thought it was worth asking.

[ka-t_240]

Originally Posted by redlined600

Anyone running tt-d care to comment?
A theoretical from scratch build
205 a7 15 pts
Shocks 4pts
Free mods including e85 with a custom tune
Gutted and ballast up to weight.

Sorry to take it a bit off topic though.

BTW once I start running tt-d I'll be in a similar boat to you due to my existing mods unless I swap back to stock suspension. Exhaust is a worthless points spend for the frs IMO.

Exhaust = header which is worth it IMO. I guess would have to drive a properly tuned stock exhaust car on corn to see whats up.

You talking shocks only, or coilovers for your shocks?

[ka-t_240]

Originally Posted by Uplink

Just to give you an idea, my 245/40-17 Z2's (listed on Tire Rack as 25lbs) on RPF1 17x8's with no tpms weigh in at 42lbs while my stock wheels/tires/tpms weigh 41.8lbs each.

If you're going 225, definitely don't mount them on the 9's.

As to swapping sizes, looking over the rules I found this:
"7) The following DOT-approved tires and those R-compound tires with a UTQG treadwear
rating over 40: BFG Rival S, Bridgestone RE071-R, Maxxis RC-1 (examples: Kumho V700,
Kumho V720, Michelin Pilot Sport Cup & MPS Cup 2, Nitto NT01, Pirelli PZero Corsa,
Toyo R888, Toyo RA-1, Yokahama A048, etc.) +6"

So you're looking at +6 regardless of which tire compound you select, then the sizing would follow this...
"10) The following tire sizes will be used as the base tire size for each Base Class for all
vehicles regardless of their OEM tire size(s) or their Final Competition Class. All
vehicles in a given base class may use this tire size (or smaller) without a points assessment:
TTB: 265mm, TTC: 255mm, TTD: 245mm, TTE: 235mm, TTF: 215mm,
TTG: 195mm, TTH: 175mm
Tire width points assessed or points credited are determined by the difference between the
width of the largest tire on the vehicle and the assigned base tire size as follows:
Equal to or greater than: 10mm +1, 20mm +4, 30mm +7, 40mm +10, 50mm +13,
60mm +16, 70mm +19, 80mm +22, 90mm +25, 100mm +28, 110mm +31
Equal to or less than: -10mm -1, -20mm -4, -30mm -7, -40mm -10"

Which means you wouldn't have a penalty for running 245 RE's in the wet since that is TTD base size but you should actually recoup 4 points when running the RC1's. Depending on what other mods you have you may want to run the 225 RC1's for point allocation alone but be aware if it's a wet day and you were at max points, you'll be over running 245 RE's when you lose the 4pt credit.

I have enough points that would bring my car into TTC with out removing a bunch of stuff, and having to get rid of my OEM spoiler. The spoiler bugs me a lot since that is 4 Points.