HPDE experiments, results and observations

[ThunderMoose]

Originally Posted by 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 dumping 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 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 to 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.

It should actually be easier to trail brake on technical track. Usually on a tight corner, you'll have a sharp initial input but then bleed off brake as you approach the apex. You're right in that sharp angle will scrub speed, so you have to compensate that with less pressure.

When you go to LRP, I think it will be easier for me at least to discuss trail braking or at least lighter braking. Big Bend is THE perfect corner for braking less to carry more speed. If done right, its impossible to get back to throttle early. Uphill and West Bend are also corners to work on braking less.

I think you have my data. I didn't have brake pressure at the time, but this formula has a high correlation with brake pressure (at least in terms of shape).

Create a math channel to compare how we compare in braking at Big Bend, Uphill and West Bend. I never figured out left hander.

abs(IF(EQ(LT(-GPS_LonAcc,0.2),0)-GPS_LonAcc,0))

[rhyary]

General statement about my writing.
I am straggling with getting the English correct in one pass, When I read my notes, I notice mistakes that change the meaning. So I constantly edit those content type errors.

My apology in advance. If you read my posts on the SAME day I posted, I encourage you to check the next day. If you read my post the next day, I probably edited all the major content type mistakes and it is typically as good as it gets.

[rhyary]

ThunderMoose ,
>>
abs(IF(EQ(LT(-GPS_LonAcc,0.2),0)-GPS_LonAcc,0))


Will do

I am studying the virtual track walk by Speedsecrets and yes, It says that.

[rhyary]

Originally Posted by rhyary

ThunderMoose ,
>>
abs(IF(EQ(LT(-GPS_LonAcc,0.2),0)-GPS_LonAcc,0))


Will do

I am studying the virtual track walk by Speedsecrets and yes, It says that.

Ha. Your Math channels are coming with your data

[rhyary]

rhyary blue
ThunderMoose Red

Going thru Big Band @LRP on the brakes.

Thunder graph showing his skill and mine lack off.

[ThunderMoose]

Originally Posted by rhyary

rhyary blue
ThunderMoose Red

Going thru Big Band @LRP on the brakes.

Thunder graph showing his skill and mine lack off.

your speed looks good. You can see though there is time available for both of us.

[rhyary]

Originally Posted by ThunderMoose

your speed looks good. You can see though there is time available for both of us.

Well, this is a 61 second lap.
My goal is to go under 60 this year probably with RR on the rear and Cup2 on the front.

I have two front eBay R7 265/35/19 take off. looking like few heat cycles I am saving for NYST.

I also two front eBay R7 235/35/19 take off that i have not decided if I will bring to LRP on the 29th or save it for NYST

And before anyone jump, having 4 R7 for the price of less then 2 new R7 is not something to give me a hard time about. I get it that new R7s are better.

[Ximian]

Originally Posted by rhyary

rhyary blue
ThunderMoose Red

Going thru Big Band @LRP on the brakes.

Thunder graph showing his skill and mine lack off.

ThunderMoose max speed is right at the start of braking, which is expected. rhyary is braking for some time while increasing speed and then max speed is at about the moment of hitting 800 psi brake pressure.

Is that a data synchronization issue or something else?

[ThunderMoose]

Originally Posted by Ximian

ThunderMoose max speed is right at the start of braking, which is expected. rhyary is braking for some time while increasing speed and then max speed is at about the moment of hitting 800 psi brake pressure.

Is that a data synchronization issue or something else?

There could be a sync issue

[rhyary]

Respect the eBay 2017 Cup2
7x20min
7x 15min


Wear is not bad given two days at NYST @ 1:39-1:42
.
I have 3 trackdays back to back, so need to mount new fronts. Otherwise would have tried to go a third day

[Bartledoo]

So, you're saying there is no difference in speed of tires under the Hoosier?

[rhyary]

Originally Posted by Bartledoo

So, you're saying there is no difference in speed of tires under the Hoosier?

From my experience, They all the same. According to AiM data with GPS reporting 50cm accuracy. About less than two feet accuracy.

All the 100-200 tires I can don 1:38-1:40 give or take. The only one that got me into 1:37 was the ADO8r, but I think that is because it is available in 275/30/19.

This is specific to my experience. Meaning E92 M3 3500Lbs with me sitting in.

While mine is supercharged. I don't believe it makes a difference from a tire perspective.

I comparison, I was on 1:37 pace on the first session third lap the first time I tried RR 235/35/19.

With R7 265/35/19 in the second session I was on 1:36 pace, and third session I did my best tine 1:35.7. DSC = on

In the afternoon I did 1:36.1 with DSC=off.

I am just saying: pick any tire because you like the name or the logo, pay what ever you want.

but if you want to go fast, Get RR (inexpensive) or R7/A7. For Dry.

Wet is another story, the MPS4S was the fastest for me.

[Bartledoo]

Well if you're faster with any version of DSC on, then I'd argue that an accurate conclusion can't be drawn based on your results, since you're not at the limit of what any of the tires can do on a lap. Regardless of that, a 2 second range is quite large on a single lap.

[rhyary]

Next setup:
MPSCup2 Star (BMW) 265/35/19 stickers but 2016. New from TireRack
RR 295/30/19 with 7 sessions (1 day)

[dparm]

Originally Posted by rhyary

While mine is supercharged. I don't believe it makes a difference from a tire perspective.

You're asking a tire to transmit more power to the ground, and then help slow you down after building up higher speeds on the straights. A supercharger will definitely tax the tires more.

[rhyary]

Originally Posted by dparm

You're asking a tire to transmit more power to the ground, and then help slow you down after building up higher speeds on the straights. A supercharger will definitely tax the tires more.

ok.
But I am not sure it creates a differentiation among the tires. These 100-200 tread tires are all very good to begin with I think.

Anyway, if my point is that all these tires are the same at HPDE event then
Chose what ever you like. If you bring your daily to the track, there are more factors to consider.

From non-daily, not race prepped car perspective, all these tires are the same. Buy the cheapest. If you want to spend money, Buy R7, A7 or RR

[dparm]

Are you able to see individual wheel speed sensor data on your datalogger? Should be an easy way to see if you're spinning up the rear tires as you accelerate out of the corner.

This might also help illustrate if/where DSC and MDM are helping.

[rhyary]

Originally Posted by dparm

Are you able to see individual wheel speed sensor data on your datalogger? Should be an easy way to see if you're spinning up the rear tires as you accelerate out of the corner.

This might also help illustrate if/where DSC and MDM are helping.

Yes I can see individual wheels.
i can see mdm adding typically 20-50 psi brake to one front wheel if the Mdm is on.

Typically to outside front

[dparm]

Originally Posted by rhyary

Yes I can see individual wheels.
i can see mdm adding typically 20-50 psi brake to one front wheel if the Mdm is on.

Typically to outside front

It would be interesting to look at rear wheel speed against time/distance -- so you can see if the wheel speeds spike as you begin applying throttle at corner exit. It would also indicate if MDM is intervening and activating an individual rear caliper to control wheelspin.

[Bartledoo]

Originally Posted by rhyary

ok.
But I am not sure it creates a differentiation among the tires. These 100-200 tread tires are all very good to begin with I think.

Anyway, if my point is that all these tires are the same at HPDE event then
Chose what ever you like. If you bring your daily to the track, there are more factors to consider.

From non-daily, not race prepped car perspective, all these tires are the same. Buy the cheapest. If you want to spend money, Buy R7, A7 or RR

All of the 100-200TW tires are not the same though. This is false information. I understand you're trying to help people with your data, but that is simply not true.

[dparm]

Originally Posted by Bartledoo

All of the 100-200TW tires are not the same though. This is false information. I understand you're trying to help people with your data, but that is simply not true.

I think the big asterisk is that on his car, with his driving style, and his specific setup, the difference is not big enough for him to justify buying the more expensive tire. Everyone's driving style and car setup is different so it's quite literally YMMV.

@rhyary -- have you considered doing some sort of a blind test for one session? Have someone mount up a set of tires without telling you which ones they are, and see what lap time you can turn. This will remove any conscious or subconscious biases you may have about a particular tire being faster or slower.

[rhyary]

Originally Posted by dparm

I think the big asterisk is that on his car, with his driving style, and his specific setup, the difference is not big enough for him to justify buying the more expensive tire. Everyone's driving style and car setup is different so it's quite literally YMMV.

@rhyary -- have you considered doing some sort of a blind test for one session? Have someone mount up a set of tires without telling you which ones they are, and see what lap time you can turn. This will remove any conscious or subconscious biases you may have about a particular tire being faster or slower.

When I get into my car I blind test all the equipment including the tires. I care less what equipment I have, once I am on the race track

I manage the traction I have the best I can at the moment. I honestly don't say to my self I have R7, drive this way, or I have Cup2 drive that way.

All data is analyzed back when I am at home.