HPDE experiments, results and observations

[admranger]

I can't decide if I love or hate the look of the new corvette.

[rhyary]

Social Distance.
I wanted to go and see close for real, but I did not want to get close to the group.

But from afar, it looks better than the pictures.

[rhyary]

For the May 21st day, yesterday, I only menaged to get 1:39.02. The silver lining was the DSC off and the third day on 275/35/19 MPSS and first day on MPSCup2 cause the car to oversteer.

So driving the car with a loose rear end and DSC off was a bit scary for me, but I decided that for the sake of learning, this is a good thing.

Generally speaking it was a beautiful day, no traffic issue to speak off, except once when two GT3s were getting in my way, and I learned to control my rear.

Specifically, as the day progressed and the car was losing rear traction, I was tempted to put the car into "safe mode" and click the MDM on.

All kind important thoughts go thru my head.....
How bad do I want to be a better driver?
Do I really need to risk putting the car into the trees?
Do the MDM really going to save me?
The Euro MDM on (first two sessions) was letting the rear come around quite a bit, isn't that enough?

At the end, what I did not like about the MDM is not its ability to save me from a big oversteer but at 1:39.02 pace it is on a lot with small brake interferences. It is constantly apply about 50-70 PSI to one corner or another. So you can't really tell the true behavior the car. And that is what, I decided, will interfere with my learning. I have GOT to know what the car is doing in a much granular way. I need to react to movement that trigger the MDM, rather let the MDM mask the fine moments.

To counter the rear getting looser and looser, I clicked my Rear Low Speed dumping (LS) -1 to make it softer, clicked rear rebound -1, and and clicked the front shaft +1. This stabilized the rear nicely and On the last session (open track, many laps) I was back into the 1:39 (1:39.7) and mostly lived in the 1:40s.

For reference, The Corvette did 1:29 on 4 heat cycles tires and was unable to break the Viper record (1:28) He was not happy, but he had an excuse. The shop mounted the stickers rear tire on the front and the front Hoosier on the rear wheel (one side). After he did 1:29, he mounted his Hoosiers stickers to try going for the record, but as I said, one side was mounted wrong.

The GTR with the R888R was mostly at my pace on the turns but blew me away on the straights. He was at the 1:37 range and got into 1:36 once for personal best. The reason I mentioned it is that since we were on "1:39" pace in the turn, I wanted to compare his 285 R888R to my 265 Cup2 wear. At the end of the day we wore about the same the edges and that make me think I am not the only one that eat up tires in one day.

The GT2 RS was on front 265/35/20 and he had no problem going fast :-). No 18" for him.

I was in a company of many GT3, GT3 RS, GT2 RS, GTR and two or three Corvettes. Not one car was stock. I am amazed at how slow the SC E92 M3 is on the straight (I do catch them at the end of the straight because I have good brakes, I had to go there).

I will follow up with the 1:39.02 video and more data notes.

It was a good day.

[rhyary]

Stats
Date: May 21st 2020
Organization: Joey's private day
Track: NYST
Weather: Dry

Tires Front: MPSCup2 MO-1
265/35/19 2017 eBay takeoff day 1

Tires Rear: MPSS
275/35/19 2017 and 2018 eBay takeoff day 3

Brake Threshold: 600 psi (the tone you hear)

Best laptime: 1.39.02
DSC: Off
.

[rhyary]

Corvette blows by, keeping up with GT3

[rhyary]

NYST Turn 17,

Turn 17 at NYST is tricky.
There is a dip that gives you good on-camber but it is too deep to really get "into" it. Since it is a left turn, there is less of a concerns to put the inside wheel on the "on camber" portion. By placing the left wheels on the curb, the right side is in the deep on camber. The left side is pretty much ride on a leveled. It still a transition from down hill to uphill but the right side does not go into the dip area.

The video shows the approach
the pictures illustrate the point.
.
Overview

[rhyary]

Closer

[rhyary]

On top
.

[rhyary]

Putting it all together:
The challenge is to precisely ride the high edge of the curb, but not to fall to the other side, it has sharp edges. riding lower on the curb has limited benefit since it is a slippery surface .

[rhyary]

The edge is sharp enough to potential cut a tire
You DON't want to fall over!
.

[rhyary]

The dip at Turn 17 for the passenger rear is big enough that analyzing the potentiometers data shows that I am bottoming out using all 60mm of travel.

I can adjust three levels of damping on my JRZs:
Low Speed (LS) controlling slow shock moments (I guess about 10-20mm/Sec). This is on the remote canister. This is a very pronounce effect and every click feels like adding stiffness on normal road imperfection.

High Speed (HS) controlling bumps like going over a curb. This is on the remote canister

Shaft (on the shock) controlling mid corner load and more like chassis control (compression during suspension already loaded)

Since this year I am on the H&R sway bar (50%), I am softer than last year (Hotchkis @ 70% stiffer than OEM) my JRZ are already tuned to more damping than last year.

But seeing the data, I clicked +2 on the rear HS.

My hope that this will not add oversteer, but hey, I would never know unless I'll try it.

[rhyary]

Turn 17 Passenger rear goes to 320mm/sec.
Perhaps compression too fast

[rhyary]

Turn 17 rear passenger - uses all 60mm travel:
.

[rhyary]

After getting virtual coached with Races360 and reviewing the data, the goal tomorrow is to control the throttle application and trail braking.

If you review Dions from Races360 many vidoes (free and subscription) his biggest point is more full throttle rather than just more throttle.

To accomplish that, he does not want ANY throttle before the apex. In his opinion, very few turns need maintenance throttle.

In addition, he is big on trail braking into the apex to keep the weight on the nose.

So tomorrow, at NYST my goal is not to set track records with new RR on the back and used Cup2 on the front.

The goal is to apply full brake (1000psi) and to trail to 100 psi before gently releasing the brake and apply throttle at the apex.

I programmed the EVO5 GS display with one screen that shows in big numbers only two parameters. Brake PSI and Throttle %

I plan on taking it easy on the straight and focus on corner speed. Mainly this translate to keeping speed at >50mph at the slow corners.

So, I have clear marching orders for tomorrow and I hope to show improvements by end of day in specific timing of gas, brake and steering angle.

i have "permission" from Dion to have slower lap times.

My video feed has all the evidence. I will be able to see if I can execute on what I am trying to do.

[ThunderMoose]

Originally Posted by rhyary

After getting virtual coached with Races360 and reviewing the data, the goal tomorrow is to control the throttle application and trail braking.

If you review Dions from Races360 many vidoes (free and subscription) his biggest point is more full throttle rather than just more throttle.

To accomplish that, he does not want ANY throttle before the apex. In his opinion, very few turns need maintenance throttle.

In addition, he is big on trail braking into the apex to keep the weight on the nose.

So tomorrow, at NYST my goal is not to set track records with new RR on the back and used Cup2 on the front.

The goal is to apply full brake (1000psi) and to trail to 100 psi before gently releasing the brake and apply throttle at the apex.

I programmed the EVO5 GS display with one screen that shows in big numbers only two parameters. Brake PSI and Throttle %

I plan on taking it easy on the straight and focus on corner speed. Mainly this translate to keeping speed at >50mph at the slow corners.

So, I have clear marching orders for tomorrow and I hope to show improvements by end of day in specific timing of gas, brake and steering angle.

i have "permission" from Dion to have slower lap times.

My video feed has all the evidence. I will be able to see if I can execute on what I am trying to do.

I think the key is to carry more speed by braking less until ready to commit to throttle. If you feel like you need to get into throttle earlier you braked too much initially. I think his 3 step approach is great way to tackle it. When analyzing data look for 2-3 mph increase on min speed.

[Datka]

Originally Posted by rhyary

After getting virtual coached with Races360 and reviewing the data, the goal tomorrow is to control the throttle application and trail braking.

If you review Dions from Races360 many vidoes (free and subscription) his biggest point is more full throttle rather than just more throttle.

To accomplish that, he does not want ANY throttle before the apex. In his opinion, very few turns need maintenance throttle.

In addition, he is big on trail braking into the apex to keep the weight on the nose.

So tomorrow, at NYST my goal is not to set track records with new RR on the back and used Cup2 on the front.

The goal is to apply full brake (1000psi) and to trail to 100 psi before gently releasing the brake and apply throttle at the apex.

I programmed the EVO5 GS display with one screen that shows in big numbers only two parameters. Brake PSI and Throttle %

I plan on taking it easy on the straight and focus on corner speed. Mainly this translate to keeping speed at >50mph at the slow corners.

So, I have clear marching orders for tomorrow and I hope to show improvements by end of day in specific timing of gas, brake and steering angle.

i have "permission" from Dion to have slower lap times.

My video feed has all the evidence. I will be able to see if I can execute on what I am trying to do.

You can run different compounds but even most experienced race test driver can get confused, because the car's balance can change as you warm the tires up. Different compounds will heat up at different rates and have different levels of grip.
That means that the car's balance between oversteer and understeer can change depending upon which lap you are on.
Not safe on the track IMO, even if you are not pushing the car 10/10th.
I think you said you will be at LRP on 29th? Find me and lets park next to each other in the paddock. I will bring my daily driver white 340i. You should run new R-compound tires.
We can do lead follow laps, your car should overtake mine easily, if not, then you are doing something wrong. We can discuss everything between sessions

[rhyary]

Originally Posted by Datka

You can run different compounds but even most experienced race test driver can get confused, because the car's balance can change as you warm the tires up. Different compounds will heat up at different rates and have different levels of grip.
That means that the car's balance between oversteer and understeer can change depending upon which lap you are on.
Not safe on the track IMO, even if you are not pushing the car 10/10th.
I think you said you will be at LRP on 29th? Find me and lets park next to each other in the paddock. I will bring my daily driver white 340i. You should run new R-compound tires.
We can do lead follow laps, your car should overtake mine easily, if not, then you are doing something wrong. We can discuss everything between sessions

Sounds like a plan. Thank you

Just did 1:39.5 chasing a Corvette. Tires are fine.

[dparm]

Originally Posted by datka

we can do lead follow laps, your car should overtake mine easily, if not, then you are doing something wrong. We can discuss everything between sessions :d

shots fired

[rhyary]

Originally Posted by dparm

shots fired

simply a chance to learn from a great driver.

[ThunderMoose]

Looking forward to your write up

[rhyary]

Stats
Date: June 6th 2020
Organization: NYST (15 min sessions)
Track: NYST
Weather: Dry

Tires Front: MPSCup2 MO-1
265/35/19 2017 eBay takeoff day 2

Tires Rear: Toyo Proxa RR
295/30/19 2018 eBay new

Brake Threshold: 900 psi (the tone you hear)

Best laptime: 1.39.54
DSC: Off

Notes: battling two track prepped Corvettes

[rhyary]

Some noted about 2020-06-06 trackday at NYST.

In attempt to solve some issues, I increased the JRZ rebound to 17. According to JRZ, once you go into 17-24 area you are into very slow rebound. The car felt to me nervous and as if in handcuffs. At lunch time I dialed it back -1 on all four corners back to 16. I think I have found the settings for my rebound given my f700/r900 springs

Looking at my pots data, I was bottoming out the rear passenger at NYST turn 17. I increased the HS damping from 11 to 13 and yesterday the car car felt better going thru that compression dip

eBay Cup2 fronts held for two days at NYST. The -3.5 is proving to be a winner so far with temp hot coming to 152 in and 152 out on the front passenger (doing most of the work). On the driver side it ran 152 on the inside and 131 hot on the outside. As expected. I switched left to right on end of day one, I did not switch on day 2. The tires ran consistently in the 1:42-1:39 range of the two days.

In general, while there are lots of opinions about tires, I found little data to support a significant difference among the 100-200 tread tires at speed. I think that lots of theories are being developed among enthusiasts that are not based on data, but preferences. Not that there is anything wrong with it. take is as mere observation.

In addition, I have yet to see evidence that a tire at half the price from eBay is any slower than a full priced tire from TireRack. Jury is still out on that.

Another observation - Either go with Hoosier R7/A7 or pay as little as possible for any tire you take to the track. Not talking about road noises, going in the wet and all other variables.

In the wet, the MPS4S is till the king at 1:38, but on the dry, I get it destroyed in one day. So not cost effective.

While I understand the concept of trail braking, in actuality it is difficult to implement. Specifically, I was able to trail brake into the apex only at slow 1:45 lap times. As soon as I picked up the pace in the afternoon the shape of the PSI pressure graph deteriorated into a steeper drop as I wanted. I suppose this is not something I am going to perfect in one trackday.

The idea of not allowing yourself to be on the throttle before the apex is painful, but useful. I found that without letting myself compensate for a slow mid turn with the throttle, my brains was fighting for speed by lighter brake pressure. So the concept is good for learning.

At a technical track, it would difficult to brake til the apex. At 80 deg steering angle, you are applying a lot of "braking" so with out some throttle the car slows too much on its own. That does not mean you can start the turn faster since even the entry is relative slow and the corner is long.

I am just writing notes and would be happy to hear constructive opinions.