orthojoe

Yup

redyps

Guy says they are worth 3-4 seconds. I have not driven a car on slicks but I am so tempted. Joe - as fast as you and Ben are I think the next steps is a nice light weight trailer and a set or rain tires and slicks. Who knows maybe that is how you get better tire wear. In regards to the warranty, you would have a trailer so no big deal. Also, as fast as you guys are maybe the tow rig is a reasonable backup item.

orthojoe

Oh I'm sure they are at least that much faster. Trailering is just another level of commitment that I don't want to get into. The beauty of these cars that they are still driveable on the street to and from the track. If I start trailering, I might as well get a stripped out race car or even a cup. I'm counting on my AAA membership for now to help me out. They were great when I blew a tire at Thill the other day.

Manifold

Agreed, and there's also the question of how fast we want to be going without full race car safety systems. Even a cautious driver can encounter fluids on track, have a mechanical, etc.

ipse dixit

That's the biggest one.

SanDiegoDavid

+1!

mooty

2) slicks/r7/r6/etc aren't available in the sizes you would need for stock wheels
===> you just need more wheels


3) 19" wheels require some small modifications and the clearance between the wheel and the rear LCA is uncomfortably small to me
===> small mod that takes a plier to do, i have 19" with plenty clearance. i fitted them no the car, not just based on calculations.

4) If I do run slicks, I won't go back
===> hahahaha, you know it.

5) Higher stress on the car, brakes, and my wallet
===> tell ben and chris that the price of slick is 2x actual price. let them stress out. you be fine.


u are an MD and i enable you as i am a drug dealer... erh.. drug rep...

trakmor

Joe, great journal. Appreciate all of the effort. You are a consummate professional. I know this has been covered in prior post but just wanted to revisit the question. What is the consensus on hot pressures for the cup 2's?

orthojoe

Thanks, man. I don't think there is a true consensus on best tire pressure. Michelin recommends 32/34psi hot. I tend to agree with Michelin. I run 32/33-34psi myself

Mech33

I've been keeping them at ~31-32psi max. Maybe I should try going slightly higher, but I feel like they get a little slippery starting at 33-34psi.

trakmor

Thanks, very similar numbers. I will work with them around that range.

orthojoe

So I ran the dunlops at laguna seca this past weekend. Here are my thoughts:

1) The tires grip very well. Unfortunately, I don't have good accelerometer data because it wasn't calibrated. My lateral G data is GPS calculated instead, so it's not apples to apple. My butt tells me that the tires grip a touch more than the cup2.

2) Handling at the limit is similar to cup2. Predictable, controllable

3) The tires start to fall off a little quicker than the mpsc2. After about 15 minutes the tires won't grip as well anymore and the car will start to understeer really bad. I've never seen understeer this severe in the car before.

4) wear rate. Not good. At all. If you look at the pictures below. These are of my front tires. The inner edge looks ok. The outer edge is a bit thin. However, the middle tread is getting close to being wiped away completely. My friend on stock alignment had the same thing happen to his dunlops. This is after 200 track miles (2 track days worth)





I ran tire pressures of 34/36 and the car felt pretty good when the tires were gripping. Here is what the rear tires look like. Not bad:




As far as lap times go, I ran the same exact lap time this go around as I did in the cup2. I think a fresh set of dunlops could be faster, but the wear rate is concerning.

orthojoe

Videos from Laguna:

best session at the end of the day with open space:

Fun getting through traffic with a friend

Side by side comparo of best laps between me and ben that day:

hlvg

Great videos, very smooth driving!
The guy in the Lotus took his time to move away…
It'd be great if you could point the outside camera towards the back to get an idea of how fast you pull away from some of those cars…

ExMB

I looked through my owner's manual as well as on the Michelin site for that recommended pressure and could not find anything. Would you be able to point me in the right direction?

From this I take it those very used, take off tires then? Could the front wear be corrected by lowering the hot pressure at the expense of more understeer?