HPDE experiments, results and observations

[_X]

Just did a track day at Summit Point Friday, but got cut short with what was seemingly bad gas. The car threw misfire codes for cylinders 3 and 5.

I just did a Castrol SRF fluid flush on Thursday, but the brakes were it seemed the brakes were losing bite by the end of the sessions. I have Hawk red pads. Could that be the issue?

I was fairly impressed with the Hankook RS4s. Definitely a big upgrade from my old Michelin PS2s.

Here is the video of the day below in the novice group as I am really just getting started with tracking the car. Open to feedback.

[rhyary]

Trying to brake deeper that 5 and ending up on the grass. Oh well.

The data shows that I was on 900psi going 84mph when I needed to head over the apex.

When I am on 84mph, i can be on 500/400psi or even less. So just to show how skill can help

[dparm]

I don't know if it's a rendering issue with the video, but that brake application looks weird. You were slow to ramp it up (didn't hit 100%), then braked again when you possibly realized you hadn't slowed enough. Can you post the brake trace from AIM or whatever?

[rhyary]

Tomorrow Palmer Motor Sport.
PB there is 1:51 and I hope to go below 1:50.

Changes from last week at LRP are limited to making the rear rebound faster. Looks like on the brakes the rear should stay more on the ground rather be in the air.

Going rear rebound from 12 (mid point) to 8.

[rhyary]

Not even close to 1:50. :-(
Very cold day, tires were not coming up to temperature and I was off line in places not sure about traction which affected my confidence.

Late afternoon it got a bit wormer. Few open laps from the day

[Bartledoo]

Originally Posted by rhyary

Not even close to 1:50. :-(
Very cold day, tires were not coming up to temperature and I was off line in places not sure about traction which affected my confidence.

Late afternoon it got a bit wormer. Few open laps from the day

Try to be more aggressive with your tire warm-up. What was the temp you were having trouble warming up in?

[Ximian]

Originally Posted by Bartledoo

Try to be more aggressive with your tire warm-up. What was the temp you were having trouble warming up in?

Looks like 47F.

People tend to swerve to warm up tires, which isn't great as it can increase tire wear. The cause of higher wear is swerving can warm up the surface very quickly before it gets further into the tire. With the hot tire surface, it'll start stripping off some of the compound.

Start by braking from high speed to warm up your brakes which will transfer heat into the rim and heat the tire from the inside as well. Acceleration helps quite a lot as well as long as it's not a burnout.

[Bartledoo]

Originally Posted by Ximian

Looks like 47F.

People tend to swerve to warm up tires, which isn't great as it can increase tire wear. The cause of higher wear is swerving can warm up the surface very quickly before it gets further into the tire. With the hot tire surface, it'll start stripping off some of the compound.

Start by braking from high speed to warm up your brakes which will transfer heat into the rim and heat the tire from the inside as well. Acceleration helps quite a lot as well as long as it's not a burnout.

Agreed, hard braking and accel are the way to start with cold tires. 47 degrees shouldn't be an issue. That's in the PB temp range.

[b4hand]

Randy Pobst always says braking warms up tires more than anything else.

[dparm]

LOL some weaving on the out lap is not going to make a massive difference in the tire's lifespan.

Remember that bigger tires take longer/more energy to heat up so an M3 is at a disadvantage for that out lap versus something like a Miata. My 315/335 R7s take an out lap plus 1 or 2 more to get sticky!

[Bartledoo]

Originally Posted by dparm

LOL some weaving on the out lap is not going to make a massive difference in the tire's lifespan.

Remember that bigger tires take longer/more energy to heat up so an M3 is at a disadvantage for that out lap versus something like a Miata. My 315/335 R7s take an out lap plus 1 or 2 more to get sticky!

On a soft tire with low pressure the shoulder can get f'd pretty quick.

[rhyary]

I have a pretty good tire pyrometer for this season made by Longcare. The nice thing about it is that it saves all 12 tire temps onto a memory location and at home I just save it into a spreadsheet. It has 99 mem locations.

So this year I am keeping tire temp per track day. I take it few time throughout the day.

So last week at LRP (right turning track) I got the front driver 285/30/19 up to 149f. This weekend at PMP (left turning track) I only got the outside tire up to 110. The inside was 80-90.

The last two sessions were warmer but still below 50 ambient.

[DRLane]

Originally Posted by rhyary

I have a pretty good tire pyrometer for this season made by Longcare. The nice thing about it is that it saves all 12 tire temps onto a memory location and at home I just save it into a spreadsheet. It has 99 mem locations.

So this year I am keeping tire temp per track day. I take it few time throughout the day.

So last week at LRP (right turning track) I got the front driver 285/30/19 up to 149f. This weekend at PMP I only got the outside tire up to 110. The inside was 80-90.

The last two sessions were warmer but still below 50 ambient.

When / where are you taking these measurements? Immediately after hot lap, or after the session? In the pit lane, back in paddock? Yourself or with helper?

Have you done out laps where you punch it for 2-3 seconds then brake hard, and repeat? The accel will heat the rears, the braking will heat pads and fronts, after a few rounds should be getting hotter. Then some wide back weaves with maintenance throttle. Then aggressive lap 7/10.

Somethings not right if you're unable to bring tires up to temp in sub 50 degrees. That should be your happiest place for the SC.

The video also had a lot of low speeds corners in high gears, and coasting or light maintenance throttle on the back of the long straight before the sweeping left hander. Was that out of fear of tires?

[dparm]

Originally Posted by DRLane

When / where are you taking these measurements? Immediately after hot lap, or after the session? In the pit lane, back in paddock? Yourself or with helper?

If the answer is not "mid-session in the hot pits", then you may as well put the gauge on eBay and just go off how the tires feel/pressures.

[Bartledoo]

Originally Posted by dparm

If the answer is not "mid-session in the hot pits", then you may as well put the gauge on eBay and just go off how the tires feel/pressures.

Really need a sensor array over the tires with live data logging, to see what the temps are doing entry, mid, and corner exit.

[tsk94]

Originally Posted by dparm

If the answer is not "mid-session in the hot pits", then you may as well put the gauge on eBay and just go off how the tires feel/pressures.

Pretty much. Really, it only works well with a helper in the pits. Do 2-3 hot laps and have them fully up to temp. Come into pits at the end of a flyer and have the helper check one side of the car and repeat with the other side.

[DRLane]

Originally Posted by Bartledoo

Really need a sensor array over the tires with live data logging, to see what the temps are doing entry, mid, and corner exit.

I want that! Tried the TPMS Bluetooth sensors caps for live pressure mid lap and it's not worth it.

I have the memory pyrometer too, and even coming in from hot lap, mid session, by the time I get out of the harness and grab the unit. Tires are cooling. Need a pit crew member to make it work.

[dparm]

Originally Posted by DRLane

I want that! Tried the TPMS Bluetooth sensors caps for live pressure mid lap and it's not worth it.

You can buy thermal cameras that go in the wheel wells and read/log the data into an AIM setup.

https://www.aimshop.com/products/aim...re-sensors-kit

Here's a demo of a similar system:

[dparm]

Originally Posted by DRLane

I want that! Tried the TPMS Bluetooth sensors caps for live pressure mid lap and it's not worth it.

I have the memory pyrometer too, and even coming in from hot lap, mid session, by the time I get out of the harness and grab the unit. Tires are cooling. Need a pit crew member to make it work.

Many DE clubs don't allow hot pits, and if they do, you'll probably get in trouble for coming in too fast to get an accurate reading.

[DRLane]

Originally Posted by dparm

Many DE clubs don't allow hot pits, and if they do, you'll probably get in trouble for coming in too fast to get an accurate reading.

I'm generally only there on unaffiliated open lapping days in which anything goes. Just best to leverage a buddy

[rhyary]

Originally Posted by dparm

Many DE clubs don't allow hot pits, and if they do, you'll probably get in trouble for coming in too fast to get an accurate reading.

We have an open day at NYST on April 23rd.
will have friends that can take temp of hot lap.

at LRP and PMP it is not a problem to stop at pit lane after a hot lap. A friend or a crew is the problem. Anyone volunteer?

[DRLane]

Originally Posted by rhyary

We have an open day at NYST on April 23rd.
will have friends that can take temp of hot lap.

at LRP and PMP it is not a problem to stop at pit lane after a hot lap. A friend or a crew is the problem. Anyone volunteer?

I know you run back to back laps, but sometimes it's best to befriend someone that's running in the opposite sessions. And do it for each other.