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S197 BOSS 302 Race Car Build Thread Build Thread

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ArizonaBOSS

Because racecar.
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8,730
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Arizona, USA
Update on braking performance with the new 380mm pro kit from PAE in the front and FTBR 13" kit in the rear:

AIM GPS data says I've picked up almost 0.30g of decel for the same pedal input. -0.73 before and -1.03 after. (Blue and green traces are new kit, red trace is stock brembos and rears). Comparing blue and red traces (pedal pressure roughly the same at this point).

KCQ0ms7.png
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
OK so last night the final pieces of the puzzle arrived to get the car back in racing condition for Chuckwalla on the 13th and 14th: Splitters!

I am using the stock "street" splitter sandwiched between the WC splitter to have a cheap and OEM-fitting spacer for the WC splitter. It pushes the WC splitter down another 3/8". Not sure if this will do anything I can feel but we will find out.

Street splitter mocked up with the broken original WC splitter:
xJIPlbQ.jpg

My wife's sign shop was able to cut two WC splitter forms from a sheet of 4'x8'x0.375" ABS plastic. Thanks to @captdistraction for the design template used for the cut! This is the first time I've tried to make my own splitter. Interesting stuff. The raw forms came out great. Here is one with drill locations started.
EspvDuc.jpg
dcARwKO.jpg

All drill locations piloted with 1/8" bit (save for the front support holes--didn't have anything left to make a guide for those, so I had to do them later with the supports mocked up:
BAOBDqM.jpg

Then I flipped the piloted board over and used a 9/64" countersink drill to make 1/2" wide countersinks for the mounting screws. This keeps the lower surface flat(ish). After the counterbores were done I flipped the board over again and drilled out the holes using a 1/4" bit from the top side.
EvIbMF4.jpg
hObSbnG.jpg

Splitter stack mounted up. Looks a little goofy compared to this same concept using the LS splitter, but we'll see how it works.
3OJsfg7.jpg

Installed the new splitter rods from Fully Torqued Racing ($65 vs. $275+ OEM, lol):
lcBCVmr.jpg

Then I used painters tape and a sharpie to measure the rods' distance from the front and centerline of the splitter to ensure uniformity before drilling. Finished product:
zGpOsBy.jpg

Tonight I should be able to get the car back on the ground, washed, and put the new TRACKMustangsOnline decals on the rockers. Then she's ready to race!
 

captdistraction

GrumpyRacer
1,954
1,698
Phoenix, Az
they look great, glad the design development process worked out. At some point I want to modify the shape to go back as far as we can on a single sheet from the nose, taking in the sides for the wheel wells to replace at least the first tray behind the splitter, however that's long down the road.

Looks great and glad the car is back in business.
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
ArizonaBOSS said:
On Friday I got the car over to the dyno, and encountered a similar situation to what @Tucson302 noted in his Time Trial thread--my car read a bit lower than I expected. My best runs were down about 15hp and 10tq across the entire rev range after installing the Kooks headers. I previously had 410whp on this same dyno in very similar weather conditions, but now she only put down 395. I was expecting something in the 420-435hp range, so needless to say I was very confused. I don't think these numbers were accurate as I've seen this install on many B302s and every single one gained power.

OK so the mystery of "The Kooks LTs and the Case of the Missing Horsepower" has been solved!

I did a shakedown run around the block (in Mexico, of course) and found that the rear brakes have been dragging since I installed my latest set of pads back there (that is, just before the dyno).
It turns out that the piston-locating pins on the backside of the rear pads were about 2x as long as a set of OEM pads and this was eating the floating caliper travel range, making the rear brakes drag. This is literally the last thing I thought of after looking over the whole rear brake setup in detail. I've never had this issue with a set of pads before but I'll have to look out for this in the future.
I dynoed and raced it like this so it's a testament to the heat dissipation ability of the FTBR rotors that nothing went wrong. My temperature strips on the rear calipers said they got up to 435F which is pretty hot, but not into the danger zone yet.

So after learning that, I took the pads out and filed down the centering pins significantly, now they let the axle and rotor spin freely. I didn't notice this during assembly because the rotor would actually shift on the axle enough to let it spin freely, but once wheel (lugnut) torque was applied it basically jammed the caliper/pad assembly into the rotor.

I took another trip to Mexico after massaging the pads and she definitely pulls harder and no drag on the brakes. I'm thinking to hit MCE Racing's mobile dyno at Chuckwalla to get some honest numbers (also determine if I want/need to pull the trigger on a CJ setup). This is also the dyno that will be at NASA Nationals this year so it's a plus to have that data point before we show up there.
 

ArizonaBOSS

Because racecar.
Moderator
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Arizona, USA
Chuckwalla Weekend Report from 2/13 and 14:

We got to Chuckwalla on Friday evening after blowing a trailer tire on the way from Phoenix. We had to stop in Quartzite to get another spare tire but overall everything went OK. We brought a grill to the track and grilled up some steaks for our group of 5 that paddocked together for the weekend. YUM :)

On Saturday the car was well-behaved and I was able to drop over 5 seconds off my previous best time going CCW when we were there with NASA two years ago (1:59.95 vs. 1:54.73).

Teu750j.png


This was enough to put me within striking distance of the two ST2 'Vettes that showed up from SoCal region, at least until they pulled out some 1:51s in the race on Saturday! I started third overall and third in-class on the grid, but got separated from the leaders at the first turn when I backed off to avoid some oil-dry left over from a car that blew an engine in the session before our race. Beating the ST2 guys from Arizona was more important for me for my regional points, so I decided that surviving T1 was more important than keeping up with the class leaders. I got stuck behind two Super Unlimited Porsche cup cars for the remainder of the race, but built a giant gap to the other ST2 cars behind me, so I was able to back off about halfway through the race and just cruise. I came in 6th overall and third in class of 5, top car from AZ in ST2.


On the podium for Saturday's race:

fK3jN8I.png
10636956_1087982327919080_8925228068536630277_o.jpg


Saturday's race ate my right front A7 tire, unfortunately, meaning I had to run all day Sunday on R7s which are at least a second slower at this track. I qualified 5th overall and 3rd in class again, and ended up fighting with another ST2 car from AZ for position here for the rest of the race. I discovered that the car was pretty pushy on the R7s, something that was getting masked by the stickier A7s, and I had been using a lot of trail-braking to get the car turned in. I am raising up my rear roll center via the watts link a bit to make the car more neutral. All the pushing made my front tires get too hot and the AZ vette was able to get by me for third in class on Sunday.

You can "see" the understeer in this photo (note angle of front wheel vs. track/path):
12719076_10101154152301534_2216592238501400156_o.jpg


s66mimD.png

All in all it was a fun weekend and I was happy to get down into the 54's (my goal was 55s going in, based on previous best times in-class from other cars in-class at the last NASA event here). That time was still 2-3 seconds faster than the best times the other AZ ST2 guys could put down. The upgraded brake package on the car worked flawlessly and I was able to match even the fastest cars' braking points without any fade or lack of confidence. It looks like I'll need to dig deep to find another couple seconds to play with the SoCal guys, but I think once I cure the understeer the car should be even faster due to less trail brake needed to rotate the car and thus more mid-corner speed, and possibly a need to get back on the throttle sooner to keep the rear planted. A good learning experience :)

Next stop is back at Wild Horse Pass East Track (again) this weekend, where the car typically runs on the front row, so I'm expecting a good showing. Then it's off to Buttonwillow in April to play with the SoCal guys again and practice for Nationals at Buttonwillow later in October.
 
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302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Drew:

Thanks so much for the fun and interesting read, as these are some of my favorite post here on TMO. Of course it's always great to see you on the podium and I wish you all the best in 2016.

It seems as though you found a significant need to lower the rear roll center via your watts link settings and I'll look forward to your future post on how this works out for you.

Kind Regards,
Dave
2HP
 

Tucson 302

2013 Black LS #439
Wow serious under steer, with my over steer issues we could combine our cars and have one perfectly balanced car! Well done and we will see you this weekend.
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
302 Hi Pro said:
It seems as though you found a significant need to lower the rear roll center via your watts link settings and I'll look forward to your future post on how this works out for you.

Kind Regards,
Dave
2HP

Dave:

Thanks for the kind words :) In actuality, I need to RAISE my rear RC. Right now it's buried in almost the lowest adjustment hole on the watts. I did this kind of blindy when I installed the watts over a year ago, and never really got bothered enough to change it (which takes all of 30 mins). It is likely too low when compared to the front RC.

GHqykRg.png

So while I'm not really raising my rear RC vs. stock (it is still lower after this adjustment), it will loosen the rear of the car up a little. I might go up one more notch as well (equal to stock or slightly lower) for experimental purposes if this initial adjustment makes the improvement I'm looking for.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Nice info on the Watts Link setting, I saved that for when I get to my WL install.

Thanks for sharing,
Dave
2HP
 
110
0
Drew, I was thinking of lowering my custom splitter so it works a bit better as well. I've read that even a 1" lowering can be significant. After re-looking at some of the Vorshlag aero build, it looks like they used some 1" square aluminum tube as the spacer and cut slits in it to bend it to the contour of the lower fascia. Lowes has a 1" square 16 ga. aluminum tube x 8' , on sale now for $19.98. For that expense it seems worth a try. A hacksaw, some effort and patience, and longer fasteners is all that it seems to be required.
You could use the left over square tube for the rear spacers as well. Any thoughts on this?
http://www.lowes.com/ProductDisplay?langId=-1&storeId=10151&catalogId=10051&productId=3053565&cId=detail
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
@cp85gt That would probably be easy enough to get done. Lowering the splitter is supposed to have a much greater effect than making it longer.

Right now I'm actually thinking to fab up a set of spring spacers for the front struts to add some additional ride height to ease loading/unloading.
Even with race ramps the splitter is still stressfully close to my trailer door when driving/winching on. I think any spacer larger than what I have now (roughly 3/8" is out of the question until I can get that settled--but overall the Al tubing seems like a solid plan.

If you are still at stock ride height (or driving the car itself to the track) then you can probably get away with the 1" spacer without issue (in theory).
 
We chose the spacer depth because it was part of the entire front end makeover where we ducted the hood and added a huge splitter that went under the engine. To mate a splitter that would go under the subframe to the front bumper cover we needed about a 1" spacer. So we used the tubing and pie cut it and welded it to make an appropriate part.

_DSC0649-M.jpg

More photos starting here: https://vorshlag.smugmug.com/Projects/Vorshlag-2011-Mustang-GT-build/i-P6kwQbz
 
110
0
That's the spacer I was referring to. I was not planning on welding it as I have no aluminum welding skills. Did you weld that to the splitter or just welded all the areas that were cut? I thought I could just sandwich the square tube in between as all the bolts running through it would hold it in place.
 

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