S197 BOSS 302 Race Car Build Thread Build Thread

[Fabman]

JRi DA. These have a low-speed compression adjustment, which I am really looking forward to having

Sweet....same spring rates as before?

 

[ArizonaBOSS]

Not exactly...

 

[Fabman]

Not exactly...

Is it a secret? I don't want to pry...

 

[ArizonaBOSS]

I'm keeping a lid on the recipes for now, although anyone that comes up close in the paddock could see the PNs on the springs . Shock valving settings will not be released.

 

[Fabman]

I'm keeping a lid on the recipes for now, although anyone that comes up close in the paddock could see the PNs on the springs . Shock valving settings will not be released.

Just curious as I know Filip likes the softer setups.

 

[Fabman]

That's who gave me the 500's.
I went 600's and then back to the 500's.
Was just curious to see if you end up doing the same.

 

[Grant 302]

I'm keeping a lid on the recipes for now, although anyone that comes up close in the paddock could see the PNs on the springs . Shock valving settings will not be released.

Just turn the springs facing in.

I've been curious what was changed with Filip's off-the-shelf valving since they were updated since I got mine. Do you have the clickers set for low speed compression only? Mine is compression/rebound and the sweeps are high-speed rebound only.

All the parts look great installed. Looking forward to your updates and review after shakedown and testing, etc.

 

[Fabman]

Just turn the springs facing in.

I've been curious what was changed with Filip's off-the-shelf valving since they were updated since I got mine. Do you have the clickers set for low speed compression only? Mine is compression/rebound and the sweeps are high-speed rebound only.

All the parts look great installed. Looking forward to your updates and review after shakedown and testing, etc.

just have the single adjustable....but it's better than no adjustables.

 

[VoodooBoss]

just have the single adjustable....but it's better than no adjustables.

Yours can be upgraded if you want DA.

 

[Fabman]

Yours can be upgraded if you want DA.

Yeah, I know....I got more immediate things to do before I go there.

 

[Grant 302]

just have the single adjustable....but it's better than no adjustables.

I know you have the SA units! I was asking Drew. Have you asked Filip about how the SA responds or what it changes in the damping curves?

Yours can be upgraded if you want DA.

Is there a published price on that? I should probably call about the price to update and rebuild mine. Not that they need either, but just to know for when the day comes.

 

[BigTaco]

I only have a few and none in great detail, unfortunately. I can get some more if you have special requests.
What I can say is that it arrived in meticulously-powdercoated condition, and to my pleasant surprise, the axle tubes were welded to the center section.
I asked for the axle side to be completely assembled including a new T2R differential and the capable folks at CorteX were able to accomodate that, took a lot of time out of my install.
I went with the "reuse stock calipers" option, which included a couple (pre-installed) relocation brackets and a pair of 2-piece floating 12" Girodisc rotors.

Here is a picture of everything after getting most of it unboxed (axle not shown in this photo):

Super cool. Yeah, I was wanting to see the welded axle tubes and some up close pictures of the hubs installed if it's not a hassle...

One of the coolest things about the cortex rear axle (besides the negative camber) is the fact that they shore up some of the weaknesses in the axle to center section by welding the tubes.....

 

[Fabman]

I know you have the SA units! I was asking Drew. Have you asked Filip about how the SA responds or what it changes in the damping curves?

I know you know...I was going to make a point, but apparently didn't get it down before I clicked out. Now I don't remember what it was, so I guess that post is pointless.

Like this one.

 

[ArizonaBOSS]

I am nearly done with getting the car ready for this weekend's debut event at Chuckwalla Valley Raceway.
I am participating in a Friday pre-event practice day, then two days of racing.

It has been a bit of a scramble to find time between delivery of the components and also spending 10 days in the California desert to help some good friends out at the King of the Hammers off-road race. I had never been to an event like that before, and it was crazy, not to mention crazy fun! That only left me a few working nights to finish up everything I had left on the car before we leave for Chuckwalla, though.

At this point, I simply need to finish plumbing my rear axle breather inside the trunk compartment, secure the rear remote reservoirs, and set ride heights/balance/alignment. That last bit might have to be done at the track depending on how things go tonight/tomorrow night--but it will get done.

I look forward to reporting out on how the new CorteX suspension does vs. my old times at this track and vs. my competitors.

 

[ls110]

Good luck this weekend Drew and looking forward to hearing your thoughts on the suspension.

 

[ArizonaBOSS]

First time the car has been on the ground in probably a month. Still need to set the ride height and balance/align but she is coming right along. Filip @ CorteX was a big help (as well as a couple other locals like @nsfw302 ) to make sure the car was ready in-time to go to the track this weekend.



Existing front ride height setting should make trailer loading easy Gotta fix that at the track

 

[the5]

Look Forward to your views on the Cambered axle! Welcome to the Cortex Family!

 

[RES_22]

Looks predatory, Drew. Well done.

 

[Bjorn Laukenmann]

See ya out there!

 

[ArizonaBOSS]

I thought things would get less busy after getting back from Chuckwalla, but it turns out I was completely wrong about that, so my race report is a bit overdue

Chuckwalla Valley Raceway is a fast and flowing track located in the aptly-named Desert Center, California. It is 2.68 miles long and can be run in either direction. From Phoenix, it's about a 4-hour tow, and there is nothing for 45 mins in either direction on the highway (between Blythe and Indio). That desolation aside, the track and facilities are nice and under constant improvement. CVR has been a favorite of Arizona racers for years and we always look forward to our events here.

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It was a busy weekend even at the track, and a weekend of carnage at that. I am pleased to report that I survived that carnage.
We got to Chuckwalla on that Thursday evening and unloaded the car. A friend set up some scales in our camp and we got to work setting the static ride height on the car and then doing a corner balance and alignment. That took about 3 hours, but the car was ready to run for the Friday practice day. Up to this point, I had driven the car (with all the changes) a total of roughly 700 feet, so Friday's practice would be very useful for learning the car again. And to make things better, I had AIM data on file from some very quick laps from 2015 (the last time I was there when it didn't rain) for comparison.

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As it turned out, I was in for a bumpy ride--literally. I had never perceived Chuckwalla as being a "bumpy" track, but with the new setup it was readily apparent that the track is far from smooth. I spent most of the day on Friday adjusting damper settings to try and deal with the undulations of the track but everything was a compromise and the car was very bouncy. The primary reason for this is that in all of my discussions with CorteX, I had only mentioned that my focus with the new setup was to WIN at COTA. As such, the spring rates delivered in my package were based around running on a glass-smooth Formula 1 track. It was a bit of an oversight on my part, but the reality of the situation is that most of the tracks this car will run on will be "good" surface quality at best, and most will be bumpy. I couldn't find a damping setting that I was thrilled with, but I was able to land on settings that I could manage for the weekend--and despite the bounciness, the car was producing a ton of grip. AIM data shows the car generating as much Lateral G on the sticker R7s I was scrubbing in as it did on sticker A7s from my prior setup.

Lateral G-Force AIM data traces. Green is previous setup with sticker A7s. Blue is un-optimized CorteX setup on sticker R7s.
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I was within a second or so of my previous best lap time as well, which was decent considering the setup was not anywhere near optimized, and I was driving around the setup more than driving with it. So, once we make a few spring rate changes, this car is going to really fly, and I have a very good baseline setup for my two trips to COTA later this year And then I can slap some A7s on it, too
Filip at CorteX was a saint during the test day as well, I sent him about a billion text messages regarding car behavior and setup, and he was able to respond quickly with advice that helped make the most out of the package I had to work with that weekend.

AIM data traces from Chuckwalla CCW config. Green is previous setup with sticker A7s. Blue is un-optimized CorteX setup on sticker R7s.
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It's important to note that while my times this outing were slower than my best from before, this was mostly to re-adjusting myself as a driver to the new suspension components and car behavior. It's fairly easy to see the inconsistencies in driving between the two graphs. I had to push myself to be able to exploit the earlier and more-aggressive corner exit throttle application. I didn't start to capitalize on that until the final race on Sunday (after these graphs were recorded), but once I started to trust the rear of the car, the cambered axle setup was very rewarding. Another difference this time out is that it was my first run with the new T56 Magnum transmission, which shifted flawlessly on the few occasions I needed to shift. I found that with the increased power and torque from the new intake cams, I could run the entire track in 3rd gear (would be 4th gear in an MT82 car) and just focus on steering, braking, and throttle inputs. There are definitely more than a few tenths to be gained in the slowest spots on the track if I downshift and use the extra thrust coming out of those corners (#8,9,10 and 16 on map above).

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The weekend's races were a bit of a mess. This was a crossover event between NASA AZ and NASA SoCal, and this was the first event of the year for the SoCal guys. The Red Mist was nearly palpable. In both days' races there were multiple contact incidents between out-of-class cars (cars that are technically not racing each other). I qualified second of five in class for Saturday's race, but got separated from the leader by the backmarkers in ST1 at the start. I wasn't able to catch up to the leader's Z/28 as we were running about the same lap times for the duration of the race--so that initial gap at the start really helped him out. On top of that, @captdistraction, another Z/28, and our regional NASA director were all nipping at my heels as I worked through the cars at the back of the ST1 pack. Unfortunately for the class leader, he pressed a bit too hard when passing lap traffic and ended up making a "BMW Sandwich" with his Camaro, my buddy's M3, and a slow Porsche, punting the two out-of-class cars, which caused him to be disqualified from the race. That meant I "won" Saturday's race and got to take a pair of free Hoosiers home as well. Take what you can get, I say.

Saturday's Race Start: "Look Ma, No Shifting (except at the green)"

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Mixed in with the AI cars on the grid for Sunday's race

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I was thinking people would be a bit calmer for Sunday's race but it turns out that was not the case. @captdistraction and I were the only starters in ST2 on Sunday (everyone else in-class had been suspended or blown up on Saturday). After avoiding a stock car sideswiping me at the green, @captdistraction and I got a front row seat to that very same stock car spinning out on the back side of the track and taking out one of his competitors in what looked like a pretty new GT3 cup car. Fortunately, I saw the stock car start to spin as he entered the braking zone and we checked up early to avoid plowing into their mess. After that, I had a pretty solid battle with a Speed Truck from the "Super Unlimited" class. This was a great test of the new cambered rear end, as once I started trusting the car, I was able to get on the throttle harder and sooner than he could in most of the corners, putting me alongside him for a number of stretches after the corners, but his power allowed him to pull away from me a bit each time. I chose not to press most of the opportunities I had to pass that truck due to the carnage we had seen already this weekend, but I was able to get a good run on him coming onto the main straight (again thanks to the cambered rear) and went by him as we took the white flag. I won Sunday's race in-class, but partially because @captdistraction's crankshaft decided to commit suicide about halfway through the race You can read more about that in his build thread.

Aftermath:

It's been a couple weeks since the initial shakedown described in this post, and I've had a lot of time to reflect on the performance and behavior of the car. Filip at CorteX and I had a very productive conference call with JJ at JRi/Ultimate Performance and we have a strategy for the bumpy tracks. I'm going back to Chuckwalla in a couple weeks with Speedventures to test that setup out and gather some comparative data. Once we land on spring rates for the bumpy tracks, I can use the low-speed compression adjustment of the JRis to control the pitch and roll of the car to fine-tune the performance. The weekend after that, we'll be back at one of our bumpy local Phoenix tracks with NASA, and I should have a pretty potent package ready to assault the competition there. It will be a while before I can fully exploit all of these changes, but there is a lot of untapped potential left in the car right now, and I am glad to have some solid partners to help me extract all of it Stay tuned...

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