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I do not have additional reinforcement bracing the trunk, although I do have the 302S hard trunk stoppers.
It would not be a bad idea to have additional trunk reinforcement--that cannot hurt you.
I would guess your trunk lid is absorbing a fair amount of downforce that is not being transfer to the tires. My lid had significant reinforcement and found the more I reinforced, the more I was getting deformation of the lid. Not surprising when you consider the 500 pounds of downforce supposedly gained at 125mph. Just this winter I am now bypassing the lid and supporting to the frame. And shaved some pounds doing it :)
 
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@Drlee50 This is an APR GT250 wing with AJ Hartman / RHR end plates.
I do not have additional reinforcement bracing the trunk, although I do have the 302S hard trunk stoppers.
It would not be a bad idea to have additional trunk reinforcement--that cannot hurt you.

Not sure what the right call is for a weekend warrior setup; but if you don't mind driving around with a wing on your car, APR, AJ Hartman / RHR, and G-Stream all make very effective options.
I appreciate the information. Ill do more research on the APR products. I don't put that many daily driver miles on it and I don't care what other people think so a big ass wing on my car at the grocery story won't bother me a bit.

Sent from my LG-H932 using Tapatalk
 
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I would guess your trunk lid is absorbing a fair amount of downforce that is not being transfer to the tires. My lid had significant reinforcement and found the more I reinforced, the more I was getting deformation of the lid. Not surprising when you consider the 500 pounds of downforce supposedly gained at 125mph. Just this winter I am now bypassing the lid and supporting to the frame. And shaved some pounds doing it :)
Any pics of your reinforcement?

Sent from my LG-H932 using Tapatalk
 

Grant 302

basic and well known psychic
I would guess your trunk lid is absorbing a fair amount of downforce that is not being transfer to the tires. My lid had significant reinforcement and found the more I reinforced, the more I was getting deformation of the lid. Not surprising when you consider the 500 pounds of downforce supposedly gained at 125mph. Just this winter I am now bypassing the lid and supporting to the frame. And shaved some pounds doing it :)

Force gets transferred no matter what. Even if the trunk lid bends and buckles! If the angle of attack doesn't change it'll provide the same downforce.
 
Force gets transferred no matter what. Even if the trunk lid bends and buckles! If the angle of attack doesn't change it'll provide the same downforce.
You are likely right as I am no aero expert. So thinking about Drew's comment that he replaced the lid bump stops with a harder rubber stops, would this not transfer more energy to the wheels versus some energy being absorbed by the softer rubber stop?
 

Grant 302

basic and well known psychic
You're right about the energy and 'work' performed for that deflection of either the stops or the lid itself. But the force transmitted to the chassis will be the same.

For example, a 200 lb person stands on a 1 lb. plate of steel on a scale or a 1 lb. 200lb/in spring on the same scale. Both readings will be 201 lb. on the scale, but more work will be done on the spring compressed 1" vs, micrometers for the steel plate. That 'extra' energy stored in the spring or rubber stop is just stored temporarily until the downforce is reduced or the person steps off the scale.

In the case of the trunk lid, I think it's more important to prevent the angle of the wing from changing due to the rubber stops compressing rather than an energy or force issue.
 

ArizonaBOSS

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Yes, the downforce would be the same ultimately. If the trunk is flexing, there will be some transitional period or "lag" to when the DF gets applied (or relieved) fully.
However, I seriously doubt that any of us would be able to tell (or take advantage of) any improvement in that rate of DF transmission, considering the rate of change of speed (both increasing and decreasing) in these cars, and many other noise factors (driver skill being one of the biggest).
 
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Not possible to identify the impact of small changes or perturbations until you can get inside a couple of tenths each lap.
 
@Drlee50 This is an APR GT250 wing with AJ Hartman / RHR end plates.
I do not have additional reinforcement bracing the trunk, although I do have the 302S hard trunk stoppers.
It would not be a bad idea to have additional trunk reinforcement--that cannot hurt you.

Not sure what the right call is for a weekend warrior setup; but if you don't mind driving around with a wing on your car, APR, AJ Hartman / RHR, and G-Stream all make very effective options.

Sucks you're not nearby, I could of welded you up some bitchin' aluminum reinforcements.
 

ArizonaBOSS

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It was a very productive weekend at our local track (Wild Horse Pass East) this weekend. Will have a full write-up later this week or early next week. I need a break :)
 

Bill Pemberton

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Hmmmm...................no stinking write up , yet, and I even know how you did!! Late news , better than no news , speedy AZZZZBossss, hehe !
 
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ArizonaBOSS

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Sorry @Bill Pemberton ; I have actually been compiling an outline this week of my experiences since March. I hope to have it live tomorrow but I think that is a stretch. Over the weekend seems likely. I want to tie my AiM data into the reports to make everything as quantitative as possible--I need to revise some of the coloring on my graphs for consistency to avoid confusion over the course of the write up. Been super busy at work/track lately so this has been on the back burner for a while but it IS coming :)
 

Bill Pemberton

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Heh, just giving you a hard time , as know you have been upholding the TMO Badass Banner and kicking butt, so just wanted everyone else to know! We will patiently wait for your pics/videos/notes!!!
 

ArizonaBOSS

Because racecar.
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First (of 3 or 4) update of happenings since March...

Chuckwalla Test Weekend (Speedventures) - March 2018
After the initial run with the car at NASA Chuckwalla in February, it was clear that some changes would have to be made to deal with tracks that would prove bumpier than COTA (basically every other track I have ever run at, aside from Laguna Seca or Thunderhill).
Filip at CorteX set up a three-way conference call with JJ Furrillo of Ultimate Performance/JRi and myself to discuss plan of attack--softer springs, revised damping settings.
I went out and bought a bunch of different rate and length springs to be able to fine-tune the setup of the car at any track I might happen to show up at, and JJ sent a few different varieties of "spring rubbers" to be able to adjust and test different spring rates quickly.
I went to work getting the new front and rear springs installed and then corner balanced the car.
I set the static ride height "very high" compared to what I would normally run to ensure I didn't have any tire contact with softer springs.

Riding high...
Qs9i6Fk.jpg

I set up a test plan to modulate damping rates and went out to see what worked. I tested a number of different settings with shocks, and the ride was significantly better over bumps w/ softer springs. The range of damping capability of the JRi shocks was very noticeable when making changes in both high-speed rebound and low-speed compression.

7eqB0HZ.jpg

At the end of the weekend, I hadn't laid down any blistering laps, but I could have set new personal bests if not for chickening out in a few areas (bowl entry, final carousel entry onto straight)--but I did have a lot more confidence in what the car would be able to do and established a ride quality that was no longer punishing. Overall, inconsistency in my own driving prevented me from going faster, but I accomplished what I came back to Chuckwalla to do, regardless.

Green Trace is the revised settings. Slower, but largely due to not carrying enough speed at the end of straights or into fast corners--that I can adjust :)
ZxwMvTh.png

Somehow during the course of the weekend I managed to bend two brand new CCW wheels. Remember that no wheel is indestructible. I am hoping to repair these and get them back "in the rotation", all puns intended.

One other treat we had this weekend was some great hospitality by the @949 Racing folks w/ awesome taco buffet--and very entertaining Supermiata races to watch each day. A number of their drivers are here on TMO already!

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More recap and data to come this weekend!​
 

ArizonaBOSS

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NASA Wild Horse Pass East Track Weekend - March 2018

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So just one week after that Chuckwalla test weekend, we were back with NASA AZ at our familiar Wild Horse Pass East Track.
This was a track that I have a lot of time on, so it would be a good comparison of the full new setup with the CorteX JRis and Cambered rear vs. my previous MCS damper setup.
A confounding factor was that the track was recently repaved (poorly)--much bumpier in some spots than before but overall about 1 second faster w/ new pavement, judging by the performance of a number of competitors.
I made a couple changes prior to heading out for my first run of the weekend--I lowered the car 1/2 an inch all around vs. test day, and adjusted (raised) roll center height to provide less on-throttle steering. Immediately it was clear that my testing and changes from prior weeks had paid off.
The car now soaked up much of the tall curbing with ease and significantly dulled the effects of the "dragon's teeth" curbing on the inside of a few of the corners--making it very easy to use the whole track. Another thing I noticed in the first turn is that the car has never changed direction so fast in the chicane as it did now. There was so much additional grip, it was crazy.

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On Saturday I qualified second overall and second in class by about 4 tenths off of the leader, running within two tenths of the best time I had ever done at this track. My best time ever was on Hoosier A7s, and I was running R7s now. The next car in class was almost 1.5 seconds behind me.
I started on the front row for Saturday's race but had to stay content with second place for most of the race when the polesitting Honda Civic matched my pace in a straightline when launching from first gear at a 30mph roll. He pulled away from me a little bit each lap until about halfway through the race when his tires started to fall off and I was then reeling him back in. I had gotten back within striking distance when he drove off the track just before coming onto the main straight. He had lost a brake line and ended up going into a tire wall. I crossed the timing loop for a winning result, but since the race was red-flagged, the positions reverted to the lap prior to the incident and I was awarded a second place finish. The Civic and I traded a few "fastest laps of the race" including resetting the track record by over one second--my best time of the race was two tenths slower than his.

Video of the last few laps of Saturday's race:

On Sunday, having gained some further confidence in the new setup, I went out in the morning and tried to really push hard to put a good time in. My efforts were rewarded with a new personal best by almost 1.5 seconds vs. my best run with the old setup, again, this was on R7s vs. A7s with the old setup.

Considering A7s are worth 1-1.5 seconds at a short track like this, it is likely that I could have gone a full three seconds faster than my old personal best, if I were on the same tire compound (A7). Back out one second for the re-paving benefits, I figure the CorteX cambered rear and JRi shocks are worth roughly two seconds on a short track like this--and that would be even better on a track where I could really stretch the car's legs.

Data output comparing personal bests: Green Trace is CorteX Cambered Rear/JRis, Red trace is stock rear and MCS:
dspjUxJ.png
Again, here you can see the car making as much (and generally MORE) lateral grip (the top graph - "GPS_LatAcc"--note peak values nearing 1.5G in both directions) in all situations with the full CorteX setup, on R7s, compared to my prior, developed setup on A7s. My prior personal best at this track was a 58.95, and my best lap of the weekend now was a 57.565. That gap is a big deal on a short 1.25 mile track.

My plan was to test and develop this new setup only on R7s; although A7s are faster, they also have about half the life in usage minutes and heat cycles. There is no point in blowing through tires like crazy trying to dial everything in, and that took almost a year of work when I was getting started with the MCS setup. So I was quite pleased that the car was generally faster in every way on the R7s with the new setup, and I was able to get pretty close to dialed-in in only 2-3 events. And due to this, I have saved a lot of money on race tires so far--since I'm going just as fast (or faster) on a compound that lasts longer than what I was used to. On top of that, the rear tire wear is more even than stock, so overall my tires are just lasting longer. Now, when I go to COTA for the NASA National Championships in September, the car will be on A7s--but it will be pre-tailored to maximize those tires by the time they are on the car :) The easy rear roll center adjustment of the CorteX watts was also quite apparent going from Chuckwalla to WHP East, it was clear that the way the car drives off the corner can be tailored to fit different types of tracks or drivers with only a couple minutes of adjustment. It certainly took a chunk of change to get all of those benefits, but they are indeed there and highly tangible. For anyone that is on the fence about the cambered rear axle--if you can afford it, do it!

The Civic was unable to effect repairs in time to be ready for Sunday's race, and I was able to qualify on the pole, with our very own @captdistraction starting right next to me. It was another drag-race start, but this time I had the inside line and was able to sneak through T1 in the lead. This race session was combined with our small-bore race group, so navigating traffic was probably the biggest challenge of the race--including an entire catback muffler setup that had fallen off of a Spec944 Porsche! At the end of the day, it was a 1-2 finish for Team TMO overall and in ST2!

Sunday Race:
Another big difference from my experience at Chuckwalla (where I ran the entire lap in 3rd gear) was that I had to do a bunch of gear shifts here at this track--so I really got to exercise the new T56 Magnum XL from Dederichs Motorsports along with the Exedy Hyper Single clutch--wow this thing shifts quickly. Very impressed with this compared to the MT82, and combined with an MGW shifter, the shifts are short and crisp, like a bolt-action rifle.

More updates to come tomorrow on races at Bondurant's facility and COTA!
 
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captdistraction

GrumpyRacer
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Phoenix, Az
Next to my first win, sharing the front row with you at East was one of the coolest moments in my racing career.

Glad it’s coming together, don’t get too used to blowing my doors off, I’m working on that problem :)

Should be one hell of a contender at nationals, be sure to manage those A’s towards the end of the champ race
 

ArizonaBOSS

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Next to my first win, sharing the front row with you at East was one of the coolest moments in my racing career.

Glad it’s coming together, don’t get too used to blowing my doors off, I’m working on that problem :)

Should be one hell of a contender at nationals, be sure to manage those A’s towards the end of the champ race

There will be plenty more racing between us in the future--and you'll probably be on pole for some of those--but I'm going to make you work for it :)
 
This is by far the best thread on these forums.

You have inspired me to get into HPDE, and get out on the track with my car. After my wedding in sept, ill be at more wild horse pass HPDE track days.

Keep up the great work!
 

ArizonaBOSS

Because racecar.
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Arizona, USA
NASA Bondurant Weekend - April 2018


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In April NASA AZ mixed things up a little bit and arrived at the "Main" school track at the Bob Bondurant Racing School, here in Chandler, AZ.
The configuration we ran features triple-digit blind sweepers, tight hairpin turns, and about as much elevation change as you can get in the Phoenix Valley.
This is the track that Bondurant uses for their racing schools the most, and it is typically a private facility open only to employees and students--so when our NASA AZ clan brokered a deal for a race weekend, many of us jumped at the chance to run.

A handful of us had run here before, sort of, with our sister group ProAutosports during their annual Thanksgiving weekend events, however at those events the track is joined with the Wild Horse Pass "Main" track making a 2.75 mile combined road course, instead of the 1.6 mile configuration we would run this time.

I have raced here before, sort of...
upload_2018-5-27_9-19-44.png

It was a bit of a relaxing weekend for me, actually. Other than camber change, I didn't have to really touch the car since the prior month's event at Wild Horse Pass East. And while a number of competitors complained about the bumpy and choppy pavement, my setup was already poised to make the most of these surfaces.

Despite that advantage, I didn't qualify so hot for Saturday's race--partied too hard the prior evening and was feeling it on Saturday morning. I ended up 4th overall and second in-class as we took the green.

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I stayed in second for a few laps as I shook off the cobwebs and observed the leader's line, then got a good run going to a spot where I could strike, and took the lead away. I also managed to get around an ST1 Porsche in that same lap, and that buffer guided me to a victory on Saturday, and second overall behind an SU World Challenge Viper.

31131711_577856745931893_4761357859097149440_o.jpg


Saturday's Race:

Our Sunday starting positions would be determined by our fast laps in Saturday's race. During Saturday's race I ran just under 1 second faster than I did in qualifying, on the same tires, in hotter weather. My time during the race was good enough to put me on the Pole in-class and second overall for Sunday's race.
I got off to a good start but was hounded in all of the slow sections of the course by my competitor in his supercharged Honda Civic. I had a clear advantage on the faster sections of the track including the blind-crest sweepers, but the low-speed tight turns in some sections of this track favored the 2300-pound Honda compared to my 3500-pound S197. On top of that, it appeared that my tires had reached the end of their generally-consistent performance and it was very difficult to get the rears to hook up. As such, I was forced to take a defensive line in the sections of a track where the Honda had the advantage. This worked great for about the first third of the race, until I made a mistake and went in too fast to one of the slower corners. I was pushing too hard (and now literally pushing) my way off of the line, which opened up a window for the Honda to take away the inside of the corner from me. Again, it was the same story as at East track--he pulled away from me slightly, but then as his tires fell off, I reeled him back in. I was all over his bumper for the last 1/3 of the race, however he was also familiar with the advantages of the defensive line and used that to hold me off until we crossed the finish line! It wasn't a win for me but it was one of the most entertaining and challenging races I'd had in a long time, and really exemplifies the beauty and flexibility of the NASA "Super Touring" power-to-weight based ruleset, where such vastly different cars can be highly competitive with one another. Despite coming in second place, I did manage to set the track record for ST2 while reeling the leader back in during the race.

Sunday's Race:

Here is a bit of analysis of my best lap of the weekend using CorteX's cambered rear and JRi dampers vs. my best "portion" of the lap from the larger "Mondo" configuration on A7s MCS setup. Since the "Mondo" lap is on a longer/different track, I have overlaid and circled the section of the graphs to pay attention to.


CorteX Cambered Rear/JRi/R7 in Green; Stock Axle/MCS/A7 in Red:
OWBbVdM.png
Again, a continued finding is that this setup is able to generate a ton of grip (top graph, "GPS_LatAcc") on the less grippy of two compounds of tires. When I finally do slap the grippier A7s on, this thing is going to be an absolute rocket ship.

Let's look a little closer at some of the data--there are a couple good examples of how the cambered rear, watts, and shock setup gives an advantage vs. a "conventional" S197 setup.

6wIoKNr.png
On the back side of the track in the high-speed sweepers, I was able to confidently feed in more throttle coming out of the corners (Arrows 1 and 2, green trace) compared to before. This resulted in more MPH carried through this section (note higher MPH green trace in the region around Arrow 3), which translated into a lap time improvement vs. the prior best lap (See increasing magnitude of red line compared to green reference time line at Arrow #4).
One important thing to note is that due to the configuration difference entering the Start/Finish straight, the throttle application entering the first corner and set of sweepers is notably lower since the entry speed is so much higher already (Arrow 5 throttle, Arrow 6 GPS speed).
The configuration entry speed difference is worth about 0.4 second on this short track, and what I was able to effect with the CorteX gear was about another full second on top of that. If the car had been on equivalent tires this time, that gap contributed by the suspension would be amplified considerably.

Here is the "overlap" region, zoomed in. Note bottom section of the graph is the time delta. I have the cursor set to the spot where the configurations begin to diverge--at this point the combination of configuration difference (front straight speed) and CorteX suspension is 1.4 seconds faster. Looking at the delta at the "beginning" of the lap to where they converge at Turn 1, the contribution of the course configuration is about 0.4 seconds. So about a second faster with the new suspension, on slower tires.
KRtRB2G.png

That earlier throttle application was worth almost 8mph speed delta in that portion of the back sweepers:
xpLvxNM.png

The time advantage in that section of the track alone was worth almost half a second:
p3vn9KW.png

31317889_577856465931921_1539928084092813312_o.jpg

Stay tuned for my COTA "recon mission" write up!
 
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