HPDE experiments, results and observations

[rhyary]

Toe discussion.
Explanation of toe.


https://youtube.com/playlist?list=PL...q10iezUFDNrRRg

[dparm]

Originally Posted by rhyary

Because it fits

Rethink this approach.

[rhyary]

AiM's new GPS09 is now installed.

From Rennlist and AiM website:

—————————
The GPS09 is a 25 Hz versus 10 Hz for the GPS08. It offers about 3x the accuracy.

In RS2A, it will still show as 10 Hz but will have the better accuracy. In RS3 you will see the 25 Hz. It also has a faster cold start than the already quick GPS08.

GPS09 samples ten times per second position, speed and lateral / in line acceleration at any point of the track.

Thanks to GPS09 even the predictive lap time will be much more reliable during your race and you will know your time gap vs your best lap with absolute precision.
The GPS09 Module is available in 0.5m, 1.3m, 2m, 4m cable lengths. Or a 2m, 4m cable Roof Version ( with cable entry from underneath) specifically designed for easy installation on covered cars.

———————

I will have a much better resolution of how slow I go.

[DRLane]

Originally Posted by rhyary

AiM's new GPS09 is now installed.

From Rennlist and AiM website:

—————————
The GPS09 is a 25 Hz versus 10 Hz for the GPS08. It offers about 3x the accuracy.

In RS2A, it will still show as 10 Hz but will have the better accuracy. In RS3 you will see the 25 Hz. It also has a faster cold start than the already quick GPS08.

GPS09 samples ten times per second position, speed and lateral / in line acceleration at any point of the track.

Thanks to GPS09 even the predictive lap time will be much more reliable during your race and you will know your time gap vs your best lap with absolute precision.
The GPS09 Module is available in 0.5m, 1.3m, 2m, 4m cable lengths. Or a 2m, 4m cable Roof Version ( with cable entry from underneath) specifically designed for easy installation on covered cars.

———————

I will have a much better resolution of how slow I go.

Is this connected to a SOLO or AIM dash logger? If dash, where have you mounted yours?

[rhyary]

The GPS09 is permanently mounted on the rear shelf and connected to the permanently mounted EVO5 (in the center console)
.

[rhyary]

I just added two open track days at WGI.
That is 16 hours. June 9-10

I blame SYT_Shadow for complicating my life

[rhyary]

Finally the day has arrived.
loading up the car this afternoon.
My first 2021 HPDE tomorrow. I told my self for weeks to take it easy the first day, forecasted cold but sunny, at LRP. 7 sessions of 20 minutes.

But who am I kidding? I will be going for PB on the first session.

Coincidently i an on matched tires

Pirelli Corsa Asym 2. Front 285/30/19 and rear 305/30/19.

[tsk94]

Originally Posted by rhyary

But who am I kidding? I will be going for PB on the first session.

Coincidently i an on matched tires

Pirelli Corsa Asym 2. Front 285/30/19 and rear 305/30/19.

That's the spirit!

At this point it's strange you not being on mismatched tires lol. Are you going to be running the new wing?

[rhyary]

Originally Posted by tsk94

That's the spirit!

At this point it's strange you not being on mismatched tires lol. Are you going to be running the new wing?

The new wing is arriving next week as well as Hard mount. Going to paint everything Jerez Black to match the car and hide the 71" wing.

You won't be able to see it.

I have 3 coming track days. Than between April 4th-20th will drive back to ACM foe the wing installation.

Speaking of wings

I was driving back from ACM at 80mph my pots were showing -4mm (compression) long straight line driving. Not sure what the wind was doing.

So I slowed down to 60mph and sure enough, the pots were showing -2mm. I did it number of times.

Making some assumptions that the GTS wing does nothing at 60mph and something at 80mph

Can we calculate downforce?

-2mm on rear 1100Lbs/inch Eibach?

[Datka]

Hey Rami, you are going to drive your car on the street with 71inch wing?
When I drive my car to the track and from with 61 inch wing other drivers think I am crazy
You should get a trailer now I think. You can take more spare tires, more tools, beer and hookers to the track with you.

[rhyary]

Originally Posted by Datka

Hey Rami, you are going to drive your car on the street with 71inch wing?
When I drive my car to the track and from with 61 inch wing other drivers think I am crazy
You should get a trailer now I think. You can take more spare tires, more tools, beer and hookers to the track with you.

Yes.
Crazy has never been a problem for me.

Anyway, when do I see you next at LRP?

[tsk94]

Originally Posted by rhyary

The new wing is arriving next week as well as Hard mount. Going to paint everything Jerez Black to match the car and hide the 71" wing.

You won't be able to see it.

I have 3 coming track days. Than between April 4th-20th will drive back to ACM foe the wing installation.

Speaking of wings

I was driving back from ACM at 80mph my pots were showing -4mm (compression) long straight line driving. Not sure what the wind was doing.

So I slowed down to 60mph and sure enough, the pots were showing -2mm. I did it number of times.

Making some assumptions that the GTS wing does nothing at 60mph and something at 80mph

Can we calculate downforce?

-2mm on rear 1100Lbs/inch Eibach?

This could roughly be calculated. The question being is how much does the rear suspension compress just from for forward momentum alone. Probably very little but it would be a small amount that would impact the downforce calculation.

To compress a 1100lb/in spring 2mm would be roughly 88lbs of force. Again, I'd assume some of the spring compression would be due to squat from power (even though you are at a steady speed). Perhaps 0.5-1mm? Also depends on the wind and direction. Only way to accurately test would be to do the same run in both direction and both with and without the wing element attached. But that gives you a rough estimate.

At 4mm it's ~169lbs of force. Same as above though. I'd have a hard time believing all that compression is from downforce from a GTS wing alone - but certainly some of it is.

[Datka]

Originally Posted by rhyary

Anyway, when do I see you next at LRP?

7/6/21

[dparm]

Originally Posted by Datka

Hey Rami, you are going to drive your car on the street with 71inch wing?
When I drive my car to the track and from with 61 inch wing other drivers think I am crazy
You should get a trailer now I think. You can take more spare tires, more tools, beer and hookers to the track with you.

Man I drive my car around with the full time trial decal setup. People love it. The cops always give a thumbs up.

[rhyary]

I did not set any lap records yesterday :-)
First three session were very very cold below freezing. But the afternoon got nice and great day. Last 1.5 hours open track. M2 Competition ended up hanging on the tire wall at T-4.

It was very dangerous to get off the pavement. The grass was frozen solid. The M2 got on the grass between T-3 and T-4 and slid sideways to the tire wall and got himself sideways on the wall. Driver was walking and talking like nothing happened. Amazing protection for OEM setup.

While I did not setup PB, I was right where I left off last year. With no traffic, many 1:02 in a row. So happy about that.

I can say that anyone faster was 1000Lbs lighter and race prep car. It is especially noticed when the red Nissan 350Z pass me. You can see how much faster he goes thru T-1, T-3 and T-4. While we can discuss my driving technic, a 2500Lbs car on new Hoosier just have more traction.

Finally, my car is on Epic DCT tune and I would say I have the downshift rev match working now. If it is not perfect or like the OEM, for me it is good enough and I am staying with this tune.

[Datka]

You are losing a lot of time in T-1. Looks like you lift at 6 marker, where you should start braking a lot later, trail brake all the way to the apex of t-1 and get back at the throttle there. You can brake deeper with your monster brake set-up, I guarantee you will gain at least half a second in that corner alone, maybe even more if you get it right.

[MaX PL]

Yeh way too much coasting big bend and left hander. Watch your video and monitor when you're not on throttle starting at apex through exit of turns.

[rhyary]

Thank you guys. Working on it

[rhyary]

I finished a session with suspension engineer and for next week I am adding +1 to the LS in the rear. The desired goal is to get the car to wallow less at the high speed T-4 to west bend.

Saying the car is like a Cadillac when changing direction will be an exaggeration but it will convey the idea if what I an trying to quite down.

[rhyary]

The car got progressively better after lunch but not faster.

The first 3 sessions 9, 10, 11 my settings were as follow:



cold tires 26
Front HS 16, LS 5, MS 12, Rebound 8
Rear HS 16, LS 4, MS 12, Rebound 8

Car was wallowing and I did not built confidence but did fastest lap of the day 1:01.9 and many laps on 1:02.

1pm tried HS 17 but it made the bumps on the straight too harsh and did not add confident

2pm back to HS 16, Rebound 10 and tires up to 29 cold. Car felt much better

3:30pm session - Front rebound up to 12.
car felt best but not faster. Fastest was 1:02 and many laps in 1:02.x

[rhyary]

Today trackday is at Lime Rock.
I am taking a different approach to the setup today. Rather the driving to Lime Rock soft and progressively getting the car stiffer, I have setup the car at home they way I want it to be on the track.

So for today I am on:
HS = 16 all around (-3 from full stiff)
LS = 5 all around (-5 from full stiff)
MS = 12 all around (-12 from full stiff)
Rebound = 12 (-12 from full stiff)

The main changes from last week is rebound in the rear goes from 10 to 12 and low speed rear goes from 4 to 5.

The expected positive behavior is the car to be less Cadillac-y on the high speed which will make me more confident at the high speed transitions

The expected negative behavior is rear moving about on the brakes coming into T-1.
(was not happening with rebound = 8 and 10)

Tire pressure:
I think that running last week on 26 cold was too low. I was only coming up to 30-32 hot and for a 3700Lbs car it is not enough.

Today I am going to start at 30 rear and 31 front and will let hot go up to 40psi. The rear is less of a problem.

From virtual coaching my goal today is to come to full throttle quick on exit. And transitioning from full throttle to brakes immediately.

Watching my videos I definitely have the tendency to getting off the throttle half way before going to brakes, and not applying full throttle when my steering angle is at 20 and lower. My coach consider 20 degrees SA as straight and wants full throttle, while I feel I am still turning hence still feeding in the throttle.

I have 4 sessions today of 40 minutes each and the weather is gorgeous.

[rhyary]

Well, I am happy with the setting for now.
Second day on the Corsa 2 front was not as I expected. At NYST I am used to get only 1 full day or even 1.5 days. By LRP is not as abrasive and i thought I would get more.

With the exception of first two sessions, the only way to get front grip was to be on the brakes at roughly 100-200psi. While that worked well for a while, I could not get any faster than 1:02s.

For the last two sessions I mounted on the front my spare MPSCup2 and oh boy, so much grip that I was oversteering like crazy using my braking technic. So I had to relearn driving with front grip. Still 1:02s though

In conclusion, I am able to adjust for the different grip so to that extent, I am meeting my goals of managing traction, what ever traction I have. However, It takes me too long to adjust. Two full sessions to get my confidence back. I would like to go out with new tires, and after two laps get my confidence back and go faster because I have more grip. But that is not happening yet.


As a side note, I was curios about how stiff my car is at my "stiff" settings. So I pushed on my car from the driver door frame and my I was able to move my car ever so slightly. Then I push the same way on @nicksm3's white M3 and it did not budge. So I am now wondering how stiff my car really is.

Picture of my front 285/30/19 Corsa 2. I really wanted to finish 2 days but gave up for the last two sessions.