Got a track related question? I'll try to answer.

[CSG Mike]

Originally Posted by gramicci101

What would you recommend as a fix for a street-driven car? A number of people have been having issues with fuel starvation during high-g left turns, so it's definitely something that could stand to be addressed.

Keep the tank full...

[CSG Mike]

Originally Posted by DocWalt

I've never paid attention... No room under car for small surge tank or does that still apply since it's not OEM engineered?

I ask not to be rude at all, I have a feeling my BRZ will be my track toy soon enough and the GTI has a surge tank from the factory so I've never needed to worry about it before. Too bad VW couldn't engineer the rest of the car to save their ass.

No room

I'm not a fan of external surges at all; the chance of it getting damaged and causing a fuel fire is too large.

I won't coach cars with systems like that at all. If it's not disclosed up front (as requested), I'll just give a refund to the student and go home.

[Reaper]

Originally Posted by CSG Mike

What is the setup on all the cars?

The banking at ACS is 14 degrees, and FRS's pull 2G+ there for extended (10+ seconds) periods without issue...

Street tires and RCE tarmac 2's. One NA one 450whp. The 3rd car is 225 whp built NA with JRZ'S still on street tires. We also had fuel starve at AMS on the roval. All e85. Atl brz is one of the cars.

[troek]

Originally Posted by Reaper

Street tires and RCE tarmac 2's. One NA one 450whp. The 3rd car is 225 whp built NA with JRZ'S still on street tires. We also had fuel starve at AMS on the roval. All e85. Atl brz is one of the cars.

225whp na?? thats got to be the highest ive seen for sure.

[DarkSunrise]

Originally Posted by DarkSunrise

If anyone is wondering about engine logs with OFT stage 2 at the track, here's mine.

http://datazap.me/u/darksunrise/trac...og=0&data=1-14

You can see a fair amount of knock in the form of FLKC, although IAM was solidly 1.0 and didn't drop.

In terms of fuel I was running:

- 2/3 of my tank was a bad batch of 93 octane (I filled up the day before my track event and was suddenly seeing knock on the street)
- 1/3 of my tank was 100 octane from the track

Call it 94 octane maybe. Definitely a good idea to add 100 octane or use e85 at the track. Later in the day, I later added another 1/3 tank of 100 octane and the engine was happier - I had much less knock and gained a couple of mph at the end of the straight. It's nice being able to pull on those pesky S2000's!

I had also installed a Perrin oil cooler. Looks pretty effective from the log. Even during the later hotter sessions, I don't think I saw anything north of 235 F. The only downside is I think the oil cooler lines are heating up my stock airbox and increasing IATs by 10 F, maybe more. I'm constantly seeing IATs 20 F above ambient now at speed.

I'll see if I can take some logs with higher mix of 100 octane later today.

Following up on my earlier post, here is a track log with a higher mix of 100 octane, roughly 97 octane:

http://datazap.me/u/darksunrise/data...og=0&data=1-14

You can see FLKC is much reduced. Oddly though, I started seeing progressively more FLKC in later sessions, even running the higher octane. Here's a log from my 4th (and fastest) session:

http://datazap.me/u/darksunrise/data...og=0&data=1-14

Even though IAM's remained solidly at 1.0, I might start running the OFT 91 octane map at the track to be safe.

The Perrin oil cooler was great at the track though. Peak oil temps were around 235 F, exactly what I was expecting.

[Reaper]

Originally Posted by troek

225whp na?? thats got to be the highest ive seen for sure.

Yes it holds the record na. 223 whp mustang dyno. Dbw motorsports has it on their Facebook page. Built high compression NA car.

[frslee]

I went to Shenandoah circuit yesterday and I had so much fun.

Brake/tire setup
OEM rotors
Front - Project Mu HC800
Rear - stoptech street performance
Stainless steel lines
ATE type 200 fluid
Sumitomo HTR Z III

This was my second visit to this circuit, so I was more familiar with the track. I drove a bit more agrressively after each lap and I noticed at the end of each session, the brake would not work as it did in the beginning of the session. After 2nd session, I bled the brakes and there was a little bit of air in it. 3rd session, same feeling - great at beginning, fading at the end of the session.

Is the issue brake fluid boiling, so leaving moisture in line? I've read from muptiple posts that ATE200 doesn't do that great on track. I know the boiling point is the lowest among the dot4 fluids, but just making sure I change to the right fluid on my next event.

Also, any recommendation on budget rotor/pad upgrade would be appreciated! Thank you.

[Apex_BRZ]

I removed one of my front DBA rotors to do some work to the ducting. On the back side, there was a perfect imprint of the carbotech pad. My previous reported issue was the pulsing, which we determined must be from the pad material that appeared to have melted on the visible front side.

Now that I've taken the rotor off, I can see a perfect impression of pad material in the shape of the pad on the back. The front doesn't have that. Seems to me that the rear pad stuck to the rotor when it was parked in the paddock. I checked the slider pins before the track day, and they appeared ok. Any thoughts on why this happened?

[CSG Mike]

Originally Posted by Apex_BRZ

I removed one of my front DBA rotors to do some work to the ducting. On the back side, there was a perfect imprint of the carbotech pad. My previous reported issue was the pulsing, which we determined must be from the pad material that appeared to have melted on the visible front side.

Now that I've taken the rotor off, I can see a perfect impression of pad material in the shape of the pad on the back. The front doesn't have that. Seems to me that the rear pad stuck to the rotor when it was parked in the paddock. I checked the slider pins before the track day, and they appeared ok. Any thoughts on why this happened?

Are you driving with the pedal dance? If not, the rear brake is probably being actuated by the EBD/E-diff/VSC/whatever, resulting in a hotter rear brake than front.

While you may have cooled the front brakes enough, the rear was probably still hot when you parked. I can't think of any other logical explanation. We know 100% that the brake was hot, but the reason why, is purely speculation.

[CSG Mike]

Originally Posted by frslee

I went to Shenandoah circuit yesterday and I had so much fun.

Brake/tire setup
OEM rotors
Front - Project Mu HC800
Rear - stoptech street performance
Stainless steel lines
ATE type 200 fluid
Sumitomo HTR Z III

This was my second visit to this circuit, so I was more familiar with the track. I drove a bit more agrressively after each lap and I noticed at the end of each session, the brake would not work as it did in the beginning of the session. After 2nd session, I bled the brakes and there was a little bit of air in it. 3rd session, same feeling - great at beginning, fading at the end of the session.

Is the issue brake fluid boiling, so leaving moisture in line? I've read from muptiple posts that ATE200 doesn't do that great on track. I know the boiling point is the lowest among the dot4 fluids, but just making sure I change to the right fluid on my next event.

Also, any recommendation on budget rotor/pad upgrade would be appreciated! Thank you.

You need to step up the pads and the fluid.

You're getting the pads hot enough that they're fading (overheating) at the end of the sessions, and losing their bite. If you haven't already, you'll boil the ATE 200 (mushy pedal) as you get faster and step up the pads.

We can help you with both. If you like the feel of the HC+800, try the Club Racer or 999 (approximately double and triple the cost of the HC+800).

[CSG Mike]

Originally Posted by Reaper

Street tires and RCE tarmac 2's. One NA one 450whp. The 3rd car is 225 whp built NA with JRZ'S still on street tires. We also had fuel starve at AMS on the roval. All e85. Atl brz is one of the cars.

Well there's your issue...

[Apex_BRZ]

Originally Posted by CSG Mike

Are you driving with the pedal dance? If not, the rear brake is probably being actuated by the EBD/E-diff/VSC/whatever, resulting in a hotter rear brake than front.

While you may have cooled the front brakes enough, the rear was probably still hot when you parked. I can't think of any other logical explanation. We know 100% that the brake was hot, but the reason why, is purely speculation.

I may not have been clear enough.

This is the FRONT brakes. It's the backside pad that that had an imprint on the rotor (side opposite the wheel that you can't see). This is also with the pedal dance.

The actual rear brakes, are 100% fine.

[CSG Mike]

Originally Posted by Apex_BRZ

I may not have been clear enough.

This is the FRONT brakes. It's the backside pad that that had an imprint on the rotor (side opposite the wheel that you can't see). This is also with the pedal dance.

The actual rear brakes, are 100% fine.

Ah, gotcha.

The inner edges of the rotors getting hotter is normal as well. The outside of the rotor has both more airflow (wheels/sides) as well as more contact area for sinking heat to the hub. It sounds like the inside pads are getting hotter than the outer pads. This is totally normal, particularly as you get more experienced. The imprint is from parking with the brakes still hot.

The cheapest fix is to add brake ducts. The long term fix is to get a BBK (or bigger BBK). This is going to save you a ton of money on pads and rotors over the long term.

For now, double your cooldown period, and do some slow laps in the pits to help keep air circulating until the brake system cools down more.

[Apex_BRZ]

Originally Posted by CSG Mike

Ah, gotcha.

The inner edges of the rotors getting hotter is normal as well. The outside of the rotor has both more airflow (wheels/sides) as well as more contact area for sinking heat to the hub. It sounds like the inside pads are getting hotter than the outer pads. This is totally normal, particularly as you get more experienced. The imprint is from parking with the brakes still hot.

The cheapest fix is to add brake ducts. The long term fix is to get a BBK (or bigger BBK). This is going to save you a ton of money on pads and rotors over the long term.

For now, double your cooldown period, and do some slow laps in the pits to help keep air circulating until the brake system cools down more.

OK. I generally try and be as careful as possible with the brakes to try and prevent this. Probably didn't do a good enough job. I'll cruise around a bit more next time. Thanks!




...still trying to fight that BBK