225 MPS4S or 245 Conti ExtremeContact Sport?

[ZDan]

Considering these options for this years time trials with COMSCC (if events happen which is of course a big maybe...)

With car points added to the FT86, I find myself having to make a huge compromise to stay in the T40 class. Either non-optimal Max Perf tires, or a ton of ballast with RE71R/A052 or the like. I'm going tires...

Considering what to run on 17x9 +35 TC105n wheels:

Option A) could run 225/45-17 Michelin PS4S at minimum weight of 2922 lb. Basically I could run half a tank of fuel and be right at the min. weight.

Option B) or could run 245/40-17 Continental ExtremeContact Sport at a minimum weight of 2867 lb.
Might take some effort to get to that weight... Maybe a lightweight battery and remove internal front bumper structure?
Or could get set of Bilstein B6 or B8 which would cost a point and run at 2907 lb.

All equal, MPS4S is maybe a tick more than half a second faster in the dry, roughly equal in the wet. Wider contis at 55 lb. lighter should be close to even in the dry. On the fence but leaning to the Michelins. Contis would look cooler tho and protect wheels from curbage better!

Any other decently fast trackable Max Perf tires out there?

To run 225 Extreme Perf tires I'd have to be at 3064 lb. at least, and 3104 lb. to run RE71R or A052. Not happenin...

car: 2017 BRZ PP with Swift BRZ Sport springs (3.8F/4.5R) and either Raceseng camber plates or perhaps Perrin offset top mounts plus camber bolts. Plan on -3.2 front, -2.5 rear camber.

[nikitopo]

What cars are in your class? BRZ and MX-5?

[ZDan]

Originally Posted by nikitopo

What cars are in your class? BRZ and MX-5?

Yup. The other "fast" T40 car is an older BRZ. He dyno'd less power so gets a break there, but is running coilovers so he has more suspension points. I think he's gonna run BFG Rival S 1.5 tires with ballast. Should be interesting!

[strat61caster]

Why not MPS4S in 245/40/17?

If you're back on time after giving the 300TW tires a shot I think the biggest step forward you'll be able to make (aside from alignment tweaks) will be going to the 200TW tires and taking the ballast.

[ZDan]

Originally Posted by strat61caster

Why not MPS4S in 245/40/17?

PS4S is a -7 point tire, Conti is a -10 point tire. 225 is zero points, 245 is +1.7 points, and 1 point represents about 40 lb.
If I ran 245 MPS4S my competition weight would be 2991 lb., I'd have to carry about 45 lb. of ballast. And I'd be +124 heavier than minimum weight with 245 Contis.

If you're back on time after giving the 300TW tires a shot I think the biggest step forward you'll be able to make (aside from alignment tweaks) will be going to the 200TW tires and taking the ballast.

I ran RE71R and NT01 previously. But since Sash and I were too fast they gave the FT86 more base points, hence he's running more ballast and slightly slower tires, and I'm (I think) trying the best of the Max Perf category tires...

I'd probably just bump up to T50 rather than run tons of ballast. I ran it in T50 last year as my backup car to the Cayman and slayed all. It was a bloodbath

[CSG Mike]

Contis are faster but wear faster.

[ZDan]

Originally Posted by CSG Mike

Contis are faster but wear faster.

Ah, verry interesting! Tire Rack and GRM tests suggest PS4S ~1/2-sec faster, but very different cars from BRZ...

https://www.tirerack.com/tires/tests...y.jsp?ttid=223
https://grassrootsmotorsports.com/ar...laren-mp4-12c/

[gcranston]

Originally Posted by ZDan

But since Sash and I were too fast they gave the FT86 more base points

Thanks for that, eh?

[ZDan]

Ordered up a set of 245 Conti ExtremeContact Sports from Discount Tire ($100 discount ends today)

If we have track events this year I'll let y'all know how it goes!

[Icecreamtruk]

Originally Posted by ZDan

Ordered up a set of 245 Conti ExtremeContact Sports from Discount Tire ($100 discount ends today)

If we have track events this year I'll let y'all know how it goes!

Let me know if you guys come to Mont-Tremblant. I know you used to and used to run joint events with Track and Time a few years back. I'll register for Tremblant if you guys do it. (I run with track and time). I think my car will be way overclassed, lots of aero but Im fast around tremblant

[ZDan]

Originally Posted by Icecreamtruk

Let me know if you guys come to Mont-Tremblant. I know you used to and used to run joint events with Track and Time a few years back. I'll register for Tremblant if you guys do it. (I run with track and time). I think my car will be way overclassed, lots of aero but Im fast around tremblant

We've been the last couple of years, but I'm pretty sure our Tremblant event this year has been cancelled Love Tremblant...

[Icecreamtruk]

Originally Posted by ZDan

We've been the last couple of years, but I'm pretty sure our Tremblant event this year has been cancelled Love Tremblant...

Yeah, I would have gone last year, but your date coincided with one of ours I think (on another track). Tremblant cancelled all events up to august this year, luckily for us, our date is the first week of september, so far so good.

[M0nk3y]

Originally Posted by ZDan

Ordered up a set of 245 Conti ExtremeContact Sports from Discount Tire ($100 discount ends today)

If we have track events this year I'll let y'all know how it goes!

Seems you already made up your mind, but my $0.02

ECS wear very quickly. They kind of have a dual compound type nature to the tire which is grippy at first and wears off rather quickly as you go through the tire. I noticed considerable differences even before the D/W started to wear away...

PS4S is substantially quicker in both dry and even quicker in the wet. The compound lends itself to blend drying conditions quite well. Only real instances where ECS is quicker in the wet is if you're in monsoon conditions and have standing water where tread void wins over compound. PS4S will hydroplane in these instances however recover really well when threshold of grip is exceeded/comes back.

ECS in the wet is more of a snappy type feel where the tire simply lets go, PS4S in the wet is like a street tire in the dry. You kind of just start losing grip and you begin to notice - however recovery time is pretty amazing where the grip just comes back if you back off 10%

I don't think you went wrong, both have their strengths. You may find the ECS to be a bit soft sidewall wise. Sizing the PS4S to 225s I think may have actually paired real well with a 17x9 tire. That tire tends to chunk shoulders if you try to push it too much.

[ZDan]

Originally Posted by M0nk3y

ECS wear very quickly. They kind of have a dual compound type nature to the tire which is grippy at first and wears off rather quickly as you go through the tire. I noticed considerable differences even before the D/W started to wear away...

Are you saying grip decreases with wear? Will keep eye on relative performance per event...

PS4S is substantially quicker in both dry and even quicker in the wet.

Car and Driver test shows the PS4S quicker in the dry and Conti quicker in the wet.
https://www.caranddriver.com/feature...-test-feature/

I'm kinda guessing that same vs. same the PS4S should be at least half a sec quicker in the dry, but maybe not, CSGMike suggests otherwise...

I decided to run Bilstien B8s in place of stock dampers so I'm taking a point there which bumped my min weight up a bit. So I'd have to run ballast even with 225 PS4S. I think 245 Contis at 2907 lb. should be about equal to 225 PS4S at 2965 lb.

Also was super-disappointed with Michelin PSS I ran for a couple of seasons on the street on my FD.

I don't think you went wrong, both have their strengths. You may find the ECS to be a bit soft sidewall wise. Sizing the PS4S to 225s I think may have actually paired real well with a 17x9 tire. That tire tends to chunk shoulders if you try to push it too much.

I was thinking the same thing, but other reasons tipped it to the Contis.

Have you run both PS4S and Conti ECS?
Tad bit late now but curious if you have comparitive lap times...

See how it goes at the track! If Sash kills me running more weight with less power on Rival S tires, I might consider those plus significant ballast...