Pineview Challenge Cup – 300 Class Recap

The Pineview Challenge Cup series began last year, and was the club’s first competitive event. I blogged about that on my brother’s site, and joined the club shortly after.

In 2019 they made this into a series of six events, with one final round to determine the winner. I wrote about the simple classing systems in Time Trials on 300 Treadwear Tires, and felt like I would have the best chance in the 300 TW “Street” category.

I decided I would use this series of events to try different things. Each event I would change one thing or another, and see what the effect would be on lap times and feel. So, as you read through this, you’ll see what I’ve done to the car. Track conditions varied with each event, and I’m sure my driving ability did as well. So this isn’t a scientific test, it’s a log.

2018 Review

In the first running of the Pineview Challenge Cup, I put down a couple practice laps in the 1:24 range. This is always a good benchmark for what I consider my “endurance pace” on S.Drives. Meaning I can run this pace consistently, pretty much all day long.

But in the heat of competition, I can drop a fair chunk of time. On this day my fastest lap was a 1:21.7.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:21.7	106	2400	1.00 g	.45	0.4

Event #1: +6 HP

Fast forward to 2019, and a new Challenge Cup series of events. The first change I made to the car was add some power. Over the winter I installed a Raceland header and a Magnaflow direct fit cat, but I haven’t had a chance to dyno it, or do any tuning. I estimate the car makes 110-112 HP based on a previous dyno run at Overdrive Automotive. It made 106 HP on their DynoJet with a DIY intake, Cobalt cat-back, and Megasquirt PNP2.

Compared to 2018, my best lap improved by .25 seconds. OptimumLap says that adding 6 hp is worth .27 seconds, so that’s really close.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:21.55	112	2400	1.00 g	.45	0.4

Event #2: Airdam, spoiler, +ride height

For the second Challenge Cup I added a small airdam and splitter. I was worried about the splitter being too low, so I raised the ride height five full turns, or about 5.5″ at the pinch welds. This was probably overkill, but roads in New England suck. A couple years ago the car was lower and also had the R-Package front lip, and it would hit things all the time. So I was a bit paranoid about going too low, and might have overdone it going too high.

I also added a DIY 3.5″ tall spoiler to the trunk. So that’s a lot of variables at once: taller, chin airdam, spoiler. I’ll make a total wild guess on what that does for drag and lift, and increase drag by .02 and decrease lift by .4. The front and rear mods added about 10 lbs.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:21.39	112	2410	1.00 g	.46	-0.4

I got second place because it was just me against a Corvette. I lost.

Event #3: Oil and water don’t mix

My 93 Miata has a 4.3 final drive ratio, and because of that, I bounce off the rev limiter or have to shift briefly into 3rd gear three times per lap. In the future I plan to replace the open diff with a 4.1 Torsen, but until then I need a solution. So I plugged in my laptop and changed the redline to 7500 rpm.

I also had a new DIY spoiler, with an extra flat piece of black plastic to make the height adjustable. I put in Paco Motorsports seat bolsters, and got a bit more aggressive on the seat foamectomy.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:21.5	112	2410	1.00 g	.46	-0.4

I only got one run in when a younger fella blew something in the Porsche he was driving and spun out in his own fluids. He was good enough to pull over and sit for the red flag. But then he got impatient not knowing what to do next, so he drove around to start/finish. He dumped fluids the whole time. ON THE RACING LINE.

He’s a young kid, doesn’t even have his driver’s license, and so his dad brings a car for him. Coolest dad ever, right? I’ll give the kid a pass this time for not understanding the meaning of a red flag. But I left Pineview after doing only one run, I don’t have patience to sit around for a track that will thereafter be slower.

That one run gave me second place behind Mike Filosi in a S2000 and in front of Dennis Rice in a Cayman S. Dennis is about 20 years older than me, but we have a good little rivalry going between us.

Event #4: Bad aero balance

For the fourth event, I switched my trunk lid from the one with a spoiler to one with a luggage rack. I can’t remember exactly why I did this, I must have been traveling somewhere. It was a mistake. Without the spoiler, the car oversteered badly. I probably also have too much chassis rake, and maybe the spoiler was covering up that problem. In any case, I was slower than other events.

The S.Drives are also wearing down quite a bit, and I keep expecting them to get faster because of less tread squirm. There are too many variables in the machine, the driver, and the conditions to know for sure, but I feel like the tires are giving up on me.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:22.1	112	2410	1.00 g	.46	0.0

I got last place this time, out of 6 cars. A bit humbling, but that’s what happens when you upset aero balance and don’t have the skill to drive around it.

Event #5: Missed it

I missed the 5th event for a late work meeting. I would have placed third or fourth I reckon. Hal and his ‘vette did low 17s, and Mike got second with a high 17, and I can’t touch that. Dennis was fast and did a 1:20.7, he would have given me a run for it.

Event #6: Wet

I’d been waiting all year for a rain event, and this time we finally got a wet track! I took off the S.Drives, which are now down to about 2/32, and mounted the 205 Conti ECS. A lot of people like them in the rain, and they apparently don’t need any heat to work.

In the first session I did a 124.1, which was pretty good compared to the other cars, on any tire. And then I ran a 123.9 in the second set. I got held up by another Miata on crappy all-season tires and had to pass him, so I only got one run in on the second session.

We usually take a break between the 2nd and 3rd sessions, to eat burgers and BS, and then suddenly the sun started to come out. I didn’t need that, I needed a downpour! But the track didn’t dry out completely, so that was fortunate.

Best Lap	HP	Lbs	Cf	Cd	Cl
1:23.4	112	2410	1.04 g	.46	-0.4 ?

In the final session I ran two 123.4s in a row, and that was good enough for first place in the 300 class. My first win! I also beat about half the cars in the 200 class, which was pretty satisfying. I even got close to Josh in his BRZ, he did a 1:22.8 on Z3s. Miatas are good in the wet.

Pineview Cup Challenge Final

I used the Conti ECS last time because the track was wet, but I know they are faster than the S.Drives in the dry, so I kept them on. Previous testing showed they are about 1.5 seconds faster than the Yoks, and so I was hoping for a 1:19 flat.

I decided to remove the top and the passenger seat. This was the finals, you go all out, right? I went over a half second faster than I thought I would. Some of this was track conditions, they were really good, and Josh went under 1:15 in his group, and that doesn’t really happen for him on Z3s (but does on RE71Rs).

Best Lap	HP	Lbs	Cf	Cd	Cl
1:18.4	112	2330	1.04 g	?	?

I put the top back on for the last session (but not he passenger seat), but by this time the track was slower. I did a couple high 1:18s, which is only a couple tenths from what my car will do with 225 RS4s. The Contis are great tires.

In the end Hal Defrees won the final event, and the Pineview Cup Challenge overall trophy. He won every time he showed up, and never took any penalty points for going off track. That was enough to beat the rest of us, congratulations.