We brought our Baby Monster Miata out to Willow Springs International Raceway (WSIR) (Rosamond, CA) with Speed Ventures for a day (Saturday) of drifting at the WSIR Balcony and a day (Sunday) of open track / time attack at the WSIR Big Track. Of course, we were not eligible to compete in the Corvette Challenge with our non-Corvette vehicle, so the title of this blog entry is not entirely true. We did however set the fastest lap time of the weekend compared to all other cars, and walk away with a Miata Challenge Time Attack Unlimited Class win at a blazingly-fast lap time of 1:29.637 in 100F weather.
On Saturday, we scrambled hard to find the right tire/wheel combination for drifting at the Balcony. We tried our 225/50R15 Toyo RA1 on 15x8 on the fronts, but the low ride height combined with Secret Element Super Angle tie rods / tie rod ends made it impossible to get anywhere near full lock without having the tire contact the frame (yes, the frame!). Then we tried to run some old 195/60R15 Falken Ziex-912 on 14x7 on the fronts, but the wheel would not clear the VW Corrado big rotor upgrade kit. We even lost the right-side vertical underbody skirt during a spin (we'll have to add some washers to the rivets next time).
We scrambled all morning to find another set of wheels and/or tires to run at the front. It just so happened that Aaron Bitterman of Speed Ventures needed to get rid of his old 205/50R15 Nitto NT01 tires. So we took them all and had a pair mounted onto the 15x8 wheels, put the pair onto the front and put the small Falkens on the rear. We were finally able to get full lock with no tire contact with any part of the car. We made some adjustments to the shock settings and performed some test runs on the Balcony course.
Once it was all set up, we handed the car over our guest driver for the weekend, Charles Ng (http://charlesngracing.com/). He is a phenomenal driving talent, with proven ability to consistently drift or set fast lap times in every car he's ever hopped into.
On Sunday, we were having problems with engine heat in the 100F ambient temperatures. A 20 minute session while feathering the throttle was not a problem, but when it came down to getting that one fast lap, the engine would begin to overheat within 1/2 of that fast lap. Even with the engine water re-route and several other cooling upgrades, the harsh weather conditions proved to be very difficult to work with.
We figured out that we could get nearly 1 blazingly fast hot lap by:
1. Starting with a completely cold engine.
2. Watering down the oil cooler, intercooler, and radiator.
3. Going through the 1 outlap (warmup) lap at a snail's pace.
4. Then bombing through 1 single hot lap and slowing down immediately for 1 cool down lap.
Our 275/35R15 Hoosier A6 tires had no problem getting "up to temperature" in this weather, as the high ambient and track surface temperatures pretty much ensured the tires always were up to temperature.
Since our last event at this track (Redline Time Attack @ Big Willow), we had made adjustments to the suspension ride heights and performed additional aero modifications to allow the car to work better at this track. With our car at 2230 lbs. (1/2 tank of fue, no driverl) and no more than 250whp (with a very limited band of usable RPM), a stock C5 Z06 was still able to walk away from us on a straight.
So we directed even more of our recent efforts to improving the overall aero balance of the car. The left-side vertical underbody skirt was still intact, as well as all the other aero goodies we previously added. Despite the unimpressive power-to-weight ratio (compared to other high HP cars), we still hoped that our little Miata could be recognized as a fast "Big Track car." As long as the car could run reliability, we knew we could set some fast lap times.
Take a close look at this static vs. high speed ride height comparison picture below. The picture on the right was taken from next to the starter tower on the front straight. We didn't have data acquisition running, but the RPM and gearing gave us indication that the car was traveling somewhere north of 130 MPH at this point. See how much closer to the ground the car was, and check out those front and rear tire-to-fender gaps!
(click to zoom in)
Do you believe in aero yet?
With the S2000 Challenge on Saturday, the Corvette Challenge (which included the very well-sorted Alvaka Networks T1 Corvette race car) and Miata Challenge on Sunday, a Viper ACR, and various other fast cars at track, we knew it was not going to be easy to achieve our goal. Our toughest struggle turned out to be the heat issues in the 100F weather. Once we found the work-around for that, we were able to set the fast lap we had been looking for.
All our hard work had paid off for the second weekend in a row (see our post about SOWS from the previous weekend). We successfully reached our goals and brought home these amazing results:
1. 1st place, Miata Challenge, Unlimited Class.
2. Fastest lap time of the weekend vs. all other cars in attendance.
3. Only car to hit a sub-1:30 lap time during this weekend.
4. Official WSIR Big Track record for a Miata during a competition event, at 1:29.637.
(Congratulations to Andrew Kidd on his fast lap time...he has a lightweight turbocharged Miata with some aero mods too!)
Here is a short blurb from Charles Ng with regards to how he felt in the Slick Auto Baby Monster:
"The car and its aero setup gives me tons of confidence. Braking power is awesome and it takes twice as much effort to lock up the brakes...very predictable setup and absolutely amazing cornering Gs, one of the best balanced street-modified time attack cars I have driven
Check out this action-packed video of the weekend with Charles behind the wheel, including both Balcony time and the 1:29.637 hot lap on the Big Track:
Here's a short video of me behind the wheel at the Balcony:
We hope that sharing our experience here can effectively demonstrate what well-balanced aero modifications can do for a slightly-overweight (compared to other Miatas), under-powered (compared to non-Miatas) at Big Willow. Do we still think Big Willow a horsepower track? Sure, why not? If we had another 100 HP on tap, we would probably have seen mid-1:25.xxx lap times...in the same 100F weather.
We'll be back to Big Track again, but perhaps not during the middle of summer. We're now working to improve the efficiency of the cooling system (we'll share updates on this as we go along) and we'll get back out to another local track for some more testing soon.
A bit of maintainence and some more modifications to Baby Monster...
This 2.5" inner diameter (ID) high-flow catalytic converter was removed:
and replaced with a 2.5" Boss Frog stainless-steel test pipe:
Exhaust sounds sans boost:
Vertical skirts were added underneath the body:
Tech: Originally seen on the 1977 Formula 1 (F1) World Championship winning Lotus 78 race car, vertical side skirts were used to seal in underbody air flow and greatly improve the efficiency of underbody aerodynamic components (i.e. flat bottom, rear diffuser, etc.). The vertical side skirts would act as walls to keep turbulent air from the outer sides of the car away from the underbody, and they would act as guides to maintain the smooth air flow under the car. Due to various reasons (perhaps some combination of politics and safety concerns), vertical side skirts were eventually banned from F1 in 1983, and were subsequently banned or highly restricted in other racing series as well.
Luckily for us, the events we drive in don't impose any restrictions with this type of aerodynamic component.
We realized that the front splitter support rods did not support the front part of the splitter too well. It turned out it was because the factory sheet metal that the support rod bracket was mounted to was very soft and flexible:
So we welded in an extra plate and re-did the support rod bracket:
We also dumped out oil from the Greddy oil catch can, and made the change to Mobil1 engine oil filter and Mobil1 15W-50 fullly-synthetic engine oil after what we believed was a reasonable break-in period:
To make sure our front splitter and rear wing would hold up to the massive aerodynamic loads we might see at the "fastest road in the west," we found a 145 lb. monkey to conduct some structural testing for us...
He checked the rear part of the front splitter:
He checked the front part of the front splitter:
He even checked the rear airfoil:
We are looking forward to having a great time at the WSIR Balcony and Big Track this coming weekend. Drifting, time attack, and perhaps some wheel-to-wheel are on our agenda. Come out and say hi if you're in the area!
Came back from a successful test day at the Streets of Willow Springs (SOWS) with Speed Ventures. We ran in the CCW direction. Those familiar with the track and incident history will know that running CCW is actually safer than running CW here.
Headed out from Orange, CA at 3:00am, picked up a member of our crew (my cousin Mike) in Monrovia, and arrived early at the MacDonald's off the Rosamond Blvd. exit. We ordered the Deluxe Breakfast for "dine-in" and proceeded on to an early arrival at SOWS.
Parked the rig between the main building and the breakfast/lunch truck, unloaded everything, and spent a bit of time training the "new guy" (Evan) how to run the AMB timing equipment for Speed Ventures.
There were probably less than 7 cars in Red group (the group I drove in) throughout the day, and only 40 or 50-something cars total for the entire event. It was quite a relaxed Friday at the track.
In the first and second sessions in the morning, I drove the car on the 225/50R15 RA1 tires, lower boost setting (11psi), with passenger. The lap times started around 1:32 and eventually got down to a 1:28.7 at higher boost (15psi) and with some changes to the shock settings and tire pressures, also with passenger.
Just past mid-day, our friend Joey Leh from The Octane Report (http://octanereport.com/) arrived at track and parked next to our spot to get some coverage on our Baby Monster. He attached video cameras to the outside of the car, took pictures and video from 3rd person angles, and even installed a Traqmate GPS data acquisition unit inside the car. This was much more than I would ever have done on my own. Thanks Joey!
We had Aaron Bitterman of Speed Ventures take the car out for a few hot laps on the RA1s with no passenger. He managed to score a fast lap time of 1:26.053 on his 2nd hot lap ever in the Baby Monster. He was still trying to get used to the response of the turbo at 15psi (we actually hadn't tuned the Greddy boost controller very well for the 15psi setting yet), and the taller sidewall of the 225/50R15 RA1 causesd some handling/balance issues. Other than those minor details, Aaron stepped out of the car quite pleased with it, and said that mid 1:24.xxx lap times were definitely possible on RA1s or equivalent tires.
I then gave Joey a few laps of ride-alongs just as the ambient temperatures soared past 95 degrees F, and only put in a best time of 1:29.x during this run. I threw in some intentional sideways action in the skidpad for a good time, which I hoped Joey would have enjoyed. He did say it would have been nice to capture that sideways action from the 3rd person point of view, but alas, he was in the car when it happened.
For the final session of the day, we swapped the tires out to the 275/35R15 Hoosier A6 to see what kind of fast lap time the Baby Monster could do. I went out for a total of around 3 hot laps without passenger and managed to get a best time of 1:25.252. This was good enough for the fastest time of the day for all cars, but we think this setup should at least be good for a 1:22.xxx lap time with the right driving (or right driver?).
Throughout the day, we did get some minor heat issues, but only on the 4th straight hot lap, and at lower speeds. The oil cooler and intercooler are stacked in front of the radiator, which is not a good thing for radiator cooling. We plan to open up one of the blocked brake duct openings (the blocking plate is bolted in and easily removed) in the bumper and just plumb it to the front of the radiator.
The paddocks were deserted by 5:30pm (boy, people sure left quickly). We were the last to pack up and leave. We headed back to town at a leisurely 55mph pace and had some Taiwanese food for dinner at Sin Bala in Arcadia.
In all, we felt quite pleased with what the car could do in hot summer weather, considering we had actually set this car up more for a higher-speed track such as Big Willow or Buttonwillow. The car had so much grip in some areas that we wished it had more power. Just imagine this: 250whp in a 2230 lb. car, wide open throttle after the bowl CCW in the off-camber right-hand turn...hugging the inside line. That's not just mechanical grip. That's also aero grip - a pretty good amount of aero grip that can be felt and utilized even at speeds starting as low as 55mph.
Here are some analysis graphs from the Traqmate data file gathered during Aaron's 1:26.053 hot lap...
Brake and turn zones map from the Traqmate data file:
The Traqmate data file from Aaron Bitterman's 1:26.053 lap is available for viewing here: SOWSCCW Test OR Test 5.tqm
You can download viewing software from http://traqmate.com/ to analyze this file and to play back the lap in real-time.
Unfortunately, technical issues kept the unit from recording anything during my Hooser A6 hot laps.
Once again, thanks to Joey Leh for letting us use your equipment to get this awesome data!
