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6.4.2.3 .....Along the entire splitter, there must be at least 1” of fascia or air dam material above/superior to where the splitter intersects the fascia/air dam, including at any air intake regions.
Difficult to see in the photos but it doesn't look like there is an air dam piece at the open for the radiator. If not it won’t pass tech.
Last edited by RS-08C6Z51; 04-06-2018 at 03:31 PM.
Fast ride & great thread. On the topic of weight reduction (non spec C5Z): Has anyone managed to reduce weight outside the axles – front & rear of car, to reduce “pendulum”? More than headlight delete, but on stock bodywork. Bumper beams, brackets, move radiator, trunk lid (FRC), Ti bolts/alu screws, etc. – anything creative?
I'm curious to see how this works out also.....you close out the air intake by and inch and the car will run hot. This is another unnecessary NASA rule for ST4 only
Originally Posted by RS-08C6Z51
The air dam/splitter rules changed for 2018.
6.4.2.3 .....Along the entire splitter, there must be at least 1” of fascia or air dam material above/superior to where the splitter intersects the fascia/air dam, including at any air intake regions.
Difficult to see in the photos but it doesn't look like there is an air dam piece at the open for the radiator. If not it won’t pass tech.
6.4.2.3 .....Along the entire splitter, there must be at least 1” of fascia or air dam material above/superior to where the splitter intersects the fascia/air dam, including at any air intake regions.
Difficult to see in the photos but it doesn't look like there is an air dam piece at the open for the radiator. If not it won’t pass tech.
there is one small piece missing here, correct. However, 98% of this splitter is legal, per Greg at NASA.
In preparation for next weeks NASA TX COTA event, we decided to upgrade the brakes. No change to the rears, but this is a take off system from what the Phoenix racing guys use on their T1 setups, we think.
Total weight added was 2 lbs, in the caliper and pad area. 12.7” /18.1lbs stock rotor diameter and weight, vs 14”/18.5lbs for the brembo.
Brembo has 1” thick pads, and was worth the weight trade off in performance!
We also removed the shark bar, and welded in a permanent harness bar. This saved 6lbs.
We’re building another splitter for a customer and decided to weigh it. This particular version is a 7” splitter, not the 4” on the red car in this post. 22.0 lbs, not bad. 1/2” multi-plywood.
We also threw some red paint on the light weight Z this week. Came out looking stellar.
Well, we decided to move from TT4 to TT3, and get everything lined out for that. No more tire size limits, and no more aero limits. We ended up leaving the 4" splitter on. It certainly needs more though.
With tire limits gone and a clear goal, we started working on fitting a 345/35/18 on the rear and a 315/30/18 on the front. We needed the large rear diameter, as we would be nearing the revlimiter in 4th, and needed the tire to get us there. As luck would have it, it worked, and we ended up Vmax of 141mph at 6100 rpm.
With the Brembos on the front now, our OEM 10.5 rears needed a 20mm spacer to clear. While this is troubling, its not the end of the world. The biggest issue was the increase in scrub radius, and the wheel/tire no longer fit in the fender. We had a fix for larger rear fenders, but got caught out on the fronts having needed wheel spacers now, and the only solution was to cut it at the track after the warm up.
Here, you can see were trying on the 18x13 Forgelines we acquired. We didnt have time to tub it, and the offsets were all wrong for that anyway. This is with in .125" of a setup for a C6Z, so we went with it. We did need a 6mm spacer to clear the tub, and we opted to remove the wheel house in the name of weight, and more clearance. ZFG on this car, its one and only purpose is to go fast.
Stock fender with a spacer... we started out with 1/2" spacers and worked our way down.
Heres the car before the body mods, and the original ride height we had for the 295s.
Fender is off. We used a screwdriver torx to finagle in there and unscrew the body fastener that is actually slotted, so we didnt have to notch the roof. FRCs are quite challenging.
New fender on. Wish we knew what brand they were, but we got them from a junkyard. LOL. It wasnt worth the hassle trying to get some L5s. If you guys have a preferred wide body brand, were all ears.
We lowered the car down all the way on the shocks, and got it as low as we could to simulate the largest bumps. This is often overlooked and will tear up a set of tires fast if not taken into consideration. This ride height was roughly 1.5" with clearance to go. We ended up trimming the fender roughly 1"
Having already been on the limit of what we believe is the max for a wetsump (1.56 LATG) and the corners we have here at MSR Cresson are not too much to worry about, with the addition of more rubber, longer sweepers of cota, and more abuse, we succumbed to adding an accusump. Not ideal, but for a few hundred dollars and some time, it was worth the life of the LS6. While the cost of the LS6 isnt the issue, its the time it takes to build and source another engine thats the killer. We dont need more power, we just need reliability.
Now we move to the power level and getting it legal.
2014 NASA Texas TT1 Champion
2015 NASA Texas ST1 Champion
2018 NASA TTU & TT3 National Champions
2019 NASA ST2 National Champion
2019 NASA Texas TT2 Champion
2020 SCCA Majors COTA GT2 pole sitter
2020 SCCA Trans Am Road Atlanta SGT Winner
2022 NASA National Champion ST2
2023 NASA National Champion ST2
2023 NASA National Champion TT2
With TT3 being 10:1 power to weight, and the car weighing roughly 2800lbs with driver, no fuel, our math was pretty simple.
10:1 base modifier.
NO advantage for BTM aero (if we took the wing and splitter off, we could bump to 9.6:1... no thanks
-.2 for SUB 3000 LBS is the only hit we took. Stock trans, DOT tires.
This made our total modifier 10.2:1 lbs per horsepower. Lets make it even math- 2800lbs plus 80lb fuel load makes it 2880, divided by 10.2 =282.35 hp. Easy enough, right? We closed the throttle and called it a day as we were already a day late to the track.
Car on track heading down into the 7/8/9 complex down hill
After some decals, and matching wheels
Driver for the weekend, Paul costas. Hes one of the winningest NASA ST drivers in the history of the texas region.
Some action shots:
The guys have dubbed the car the "sledgehammer"... Not sure why, but it stuck. Simple, yet effective.
Heres the incar of the two winning laps over the weekend.
Thanks for following along, We have some more development to do, more aero, fix a sticky clutch and tidy up the whole package. There is no doubt this car will see the teens with only 280 rwhp
for some reason you never seen dedicated track cars using brembos.
got to go to cresson for the first time a couple weeks ago. saw your banner and white C7.
love the build thread.
04-05-2018, 01:22 PM
