Thought I'd wake this thread up after a year long snooze...

Last Friday I was at Laguna Seca with Hooked on Driving. It was a cool and mostly overcast day, there were 15-20 Mustangs, a couple of race prepped 911s, a Mercedes SLS AMG, a Ferrari Challenge 458, and a random collection of other cars. I was the only Mini there. I was in B group with a couple of M3s, some 911s, an Audi RS5, a Caddy ATS, a Mustang or two, a Ferrari 458, a Corvette C5, and a Mercedes sedan of some sort. I was really looking forward to trying out the new suspension (Ohlins R&T, camber plates) and Michelin PSSs on the track. I had resolved to brake later and harder as I knew I was losing a bunch of time on corner entry by backing off early.

For the first session I didn't bother with RaceChrono or the GoPro, I figured I would take it easy and get used to the tires and get re-acquainted with the proper line. When it came time to grid, the session leader asked me "fast or slow" and I said "in the middle", aiming at row 3. He told me to go in row 2 instead, so I was the first car in the row with a BMW M3 to my right. No one lined up behind the M3 so I was the second car on the track with another M3 and a Nissan GTR behind me. The guy in front of me took off so I did too, and was quickly wondering about the tires because the car was loose and a bit of a handful. But by the time I was coming down the hill the tires had some heat in them and the car felt better. The M3 and GTR were on my tail so I pointed them by on the straight and then got to enjoy several clear laps. Afterwards I checked the tire pressures, the fronts were at 42 and the rears at 40 which seemed kind of high, so I let a few lbs out all around. I had also neglected to stiffen the shocks up so I went with -5 clicks from full stiff in front and -7 in the back.

Starting the second session people figured out where to grid, I was the top of row 3 and all the M3s, the GTR, etc. were in 1 and 2. Immediately I could feel the difference in the car - great grip, really neutral up to the limit where it would start to push a little, and I could get it to rotate by lifting the throttle. The EBC Yellow pads were working great. Immediately my lap times were right around 2:00. About half way through the session the 458 came up behind me so I pointed him by on the straight. I loved the sound as he went by. He braked really early into turn 2 so I caught up to him, I was chasing him through 2, 3, and 4, and right behind going into 5. I guess he was annoyed by the little Mini that cost 1/10 of his car being on his tail so he nailed it in 3rd gear going up the hill by the sound check station and the flag station at turn 7 had a black flag for him. He backed off and I had to follow him for a lap and a half before he finally caught on that yes those black flags really were for him. After that I had clear track and by the end of the session I was down to 1:57.59 so I was pretty happy.

The tire pressures after session 2 were still about 40 front and rear so I let another 1 psi out all around, and also cranked up the suspension a few more clicks. Session 3 was great, I had 5 out of 8 laps under 2:00 and best was 1:56.73. The car felt good, I was hitting the line pretty well, and really nailing turns 5 and 6. The first time I drove at Laguna Seca I was pretty much in 3rd gear all the way except the main straight, and as I got faster I was using 4th gear a little between 4 and 5. Now I found I was shifting into 4th gear after turn 3, holding it through turn 4, and getting up to about 95 before braking for turn 5. I was also shifting into 4th up the hill between 5 and 6, and after 6 into 7 which is pretty much flat out, and having to brake really hard before the corkscrew. I was really pleased with how the car felt, a couple of times I really pushed it through turn 10 and while it felt like all 4 tires were sliding a bit, there wasn't any hint of oversteer. I would get some understeer if I pushed too hard in turn 2, but a couple of times I got the braking and the line just right and found the car totally neutral.

Between sessions I talked with the guy driving the Corvette C5, I had been lapping him in each session so roughly 15 - 20 seconds a lap faster. He owned a Mini also and wished he had brought it, he said the C5 was a real workout. He asked if I was stock and seemed amazed that my only mods were the suspension. I was finding that in the corners and down the hill I could keep up with just about anything, though the higher horsepower cars would of course accelerate away on the main straight and up the hill and the M3s were ridiculously quick everywhere. One of the M3 drivers that I talked with said he was doing about 1:50 laps, the quicker cars would take off at the start of the session and after the first few corners I would never see them again. I also talked with the guys driving spec Miatas in group D, they were in the low 1:50s. Pretty impressive for a car with only 120 - 130 HP, though they were on race tires and were completely stripped of any excess weight.

Session 4 I was ragged and sloppy, so the less said about it the better. I wasn't hitting the line consistently. It's funny, my previous times at the track were similar - first session get used to the track, sessions 2 and 3 showing improvement, session 4 not driving well.

Last session of the day I took a coach, he was great - really helped me with positioning the car properly down the straight and through turn 1 to be in the right place to turn in for turn 2. Though I kept backing off, getting up to about 100 with the hairpin coming up is a bit intimidating. One lap I had absolutely nailed turn 6 so I was really flying coming up the hill and braked way too late for the corkscrew entry. The brakes just didn't bite at first so I went embarassingly straight while I got the car slowed down, I thought I might be going into the gravel for a moment but it all was OK in the end. The brakes definitely felt like they were fading a bit so I took it a bit easier for the rest of the session.

Overall a really fun day, I was pleased to take 8 seconds off my previous best time though most of the credit goes to the tires and suspension. After the last session I put my stuff back in the car, turned the shocks back down, and headed home. I was surprised and how much gas I went through. Previous days I had been able to fill up at home, drive to the track, do 5 sessions (about 100 miles total on the track) and drive home with gas left over. This time I filled up in Salinas about 15 miles away, and was close to empty when I left the track.

I have a lot of data on RaceChrono and GoPro video to go through to analyze what I did well and what I didn't. One thing I have noticed already is that I'm holding 3rd gear too long before shifting into 4th. I logged throttle position, RPM, Intake temp, boost, and timing advance on RaceChrono so that should be interesting to go through in detail. It looks like the Wagner intercooler is keeping the worst case rise to 10C over ambient, previously I saw a rise of 50C with the stock intercooler so the Wagner is making a huge difference. If I come up with any great insights I'll post a follow-up.

 

Nice to pick this thread up again. Sounds like you had some fun.

Looking forward to some video and data...

Your comment about "The brakes just didn't bite at first so I went embarrassingly straight..." caught my eye. It sounds like you went beyond the capability of the Yellow stuff pads. You said that you wanted to brake later and harder. If you are really going to do that then you will need a real track/race set of brake pads. Get a set of Carbotech XP10s for the front and XP8s for the rear and you will knock another second off your time. I have back to back, same day experience with both (Yellow stuff vs XP10s) on the stock S brakes and they are night and day different with the XP10s being the better pad.

If you want to stick with the Yellow stuff pads, I have that set with only 2 sessions on them that I will sell to you, cheap. PM me if interested.

 

I was definitely braking later and harder, I may have overheated the brakes or the brake fluid... previously I had been using Motul RBF600 but when Mini did the brake fluid flush it was replaced with the standard stuff. Or maybe I just blew it and braked too late. I have been happy with the Yellowstuff pads so far but you may be right and I am beyond their capability.

In any case a brake upgrade is next - probably the JCW brakes with Sneed Speed ss pistons and Carbotech pads to swap in for track days. Father's Day and my birthday are both coming up...

I am going through the analysis with RaceChrono for all the sessions to try to understand the difference between a fast lap and a slow lap, I'll also look to see if I braked too late in that situation.

 

I would suggest cooling ducts before swapping major brake components. Heat is the major problem with brakes, and the more you can get rid of the better for everything concerned.

 

The MINI brake fluid has a fairly high boiling point (446 deg F). If it was new, this should not have been any problem.

True on cooling, but the S already has ducts that dump a ton of air on the back side of the rotors and on the calipers. I had trouble with too much cooling on the inboard side of the rotors and the outboard side had not enough to keep up and I cracked the outside. I had the dust shields off at the time and had to put the dust shields back on to even things out. MINI has made all of this a "system" that works pretty well together. Not saying that a true ducted arrangement would not be better, just that this is works pretty well.

As for pads, I found the yellow stuff pads did not like late, hard braking and the fast buildup of heat this causes. This was pretty much cured by the race pads.

If you upgrade the brakes to the JCWs, there is a factory reflash of the ABS systems that I suggest you have done to compensate for the different volume of fluid that they use. Someone posted the service bulletin for this:
https://www.northamericanmotoring.co...d-list-10.html
See post 241.
I found that, without this, the DTC and the eLSD over-perform which really messes up the brakes.

 

comparing laps in RaceChrono shows that my speed was similar and I started braking at about the same point, but the one time I had an issue the speed did not start dropping as fast, then finally the brakes started working and I got slowed down. So definitely some brake fade.

Thanks for the advice, I understand the heat issue with brakes, that's why I was running Yellowstuff pads and (previously) higher temp brake fluid. As Eddie07S pointed out, the S has cooling ducts but the cross section of the stock ducting decreases a lot from the front to where it finally exits inside the wheel well. I have been thinking for a long time about how to adapt the Sneed brake duct kit to the cooling inlets in the front lower grill, I have some ideas but not a fully baked plan yet.

 

A thought - get a set of Carbotech XP-10s (Way Motors) for you stock S brakes and see what you think. That is a lot less money than a JCW sport Brake setup and you may find that it will suit your needs for a while as you progress up the experience ladder.

 

Here is a comparison of 2 laps from the 3rd session, showing my fastest lap (8) at 1:56.73 and lap 6 which was almost 2 seconds slower.

Data was recorded using RaceChrono on my Android phone with a Dual XGPS160 10Hz GPS connected via bluetooth. From RaceChrono it was exported into .vbo format, then loaded into Circuit Tools 2 from Vbox (free download.) The image is a screengrab that I annotated with the turns. (Turns 1 and 7 not listed since at MRLS they are flat out.) The speed is from the GPS, there are obviously some places (like turn 2) where it does not update properly. Lap 6 actually started out a bit quicker, then I lost all the advantage in turns 9, 10, and 11. I went back to the video to figure it out, this was where I had caught up to a slower car.

 

The Circuit Tools is really nice. Harry's lap time data will import into that program also. Did you do any comparison of lateral and linear g's (or something that shows braking)? That would also be helpful in analyzing differences. Hey, have you found a way to overlay the data onto video?

How are you liking the Dual 160 with the 10Hz? I have the 5Hz Dual that I use with Harry's lap timer. I did find one thing, though. If you drop your iPhone from 8 feet up onto an asphalt driveway, it will mess-up the phone's accelerometers and the data it takes even if the phone looks perfectly fine (the case saved the rest of the phone). Time for a new phone...

 

Finally got a chance to edit the video to do a clip of my best lap. There's plenty of room for improvement, should have been all the way to the right before turning in for turn 2, and turn 9 was not the best line, but still a pretty good lap.

Here's a link: https://www.dropbox.com/s/o04coruoxu...stLap.MP4?dl=0

The Dual160 does a great job, but doesn't seem to handle 180 degree direction changes (turn 2) well. Overall though a very nice unit.

 

Looks fun. As you say, a pretty good line and seem to be smooth. You also seem to know the track and understand where you need to tighten it up. There are also a few places where you could run the track out to the full extent. This will get you used to being in that area as you get faster. It also reduces the slip angle on the tires which increases grip and increases speed. Another useful tool is to mount the camera further back so you can see what you are doing.

I am surprised by your comment about the Dual not handling the 180; it seems that should not affect it. Curious...