Grinder's OBP

[finallymysti]

I just got back from two days at VIR. Wow, what a weekend!

To start, I got to crash in one of the villas. If any of you have seen the Top Gear episode where they go to VIR....that's where they stayed! A front row view of the "Climbing Esses", RIGHT on the track. Anyways, i started off the next morning with a rude awakening. It was supposed to be in the 70s and sunny, but instead we were greeted with 50s and cloudy. I didnt even bring a coat, and just had a sweatshirt as an afterthought! When we got down track-side, I got a ride in a buddy's track-prepped STI with some sticky rubber (one step below Hoosiers...whatever brand/model i forget). He was trying to heat-cycle his tires and bed in his brakes so he was "only 60-70%" but WOW was it eye-popping. He's got a mighty quick car and its a fun track.

So for my first run I had an instructor (especially since it's a new track to me) and tried to find the line. I ran into some overboosting problems, so for most of the session i was only doing about 50% throttle to keep my boost at maybe 10 psi. There are some corners on there where you can carry SO much speed and never expect it, and I was having trouble trusting my tires. So my instructor invited me for a ride along in his Miata. We were hauling ass around the corners and falling miserably behind on the straights. On maybe our 6th lap around through the climbing esses we got a little loose and did a nice spin into the grass in spectacular fashion. Spins are less scary than they seem, although i was glad we were going in the direction of field rather than a wall.

To keep this rambling story short, I got a new tune overnight (thanks George!!!) and put down some MUCH quicker laps. I was a few seconds faster than a new friend in a tricked-out Outback, and he was doing 2:25 by the time we parted ways, so i think that puts me at maybe a 2:21 or 2:22 with several places I KNOW I can get more speed. My instructor was teaching me the Miata line, and the "school line" but by the end I was trying the racing line and could go faster--i just didnt get enough practice by the time I had to leave.

I look forward to going back to VIR and will try to post up some pictures/videos soon.

that sounds great. the tires were probably nt01 or toyo r888. when you said you didn't trust your tires, what kind are you running? i'm guessing you were running the full course, what was you speed on the straight? those are really good times, congrats. looking forward to the video.

 

[Grinder34]

nt01 sounds right.

I'm running Hankook Ventus V12...one step down from their top street tire the RS3. They're good for the most part but especially on the first day I was still feeling them out. I'd push them 100% on the slow speed stuff, but worked into maybe 90% of their potential on the high speed turns. Incremental improvements! Last thing I want is to do an epic spin into a tire wall through the climbing esses. South bend was one turn that I dont think I ever went though at more than 80%. Not because I didnt want to or didnt try, but I just ALWAYS had more grip than I expected (meaning i braked too much going in. that turn looks slower than it is).

On both the front straight and south straight I was having to shift to 6th. The south straight I definitely had to shift well before the brake zone. On the front straight I just sort of let it coast into the braking zone instead of shifting to 6th for a second and a half. Since i'm not racing, those extra few mph dont mean much to me. Im not sure what redline in 5th is though.

 

[Batmobile_Engage]

^ GoPro videos? I can hardly wait

 

[finallymysti]

nt01 sounds right.

I'm running Hankook Ventus V12...one step down from their top street tire the RS3. They're good for the most part but especially on the first day I was still feeling them out. I'd push them 100% on the slow speed stuff, but worked into maybe 90% of their potential on the high speed turns. Incremental improvements! Last thing I want is to do an epic spin into a tire wall through the climbing esses. South bend was one turn that I dont think I ever went though at more than 80%. Not because I didnt want to or didnt try, but I just ALWAYS had more grip than I expected (meaning i braked too much going in. that turn looks slower than it is).

On both the front straight and south straight I was having to shift to 6th. The south straight I definitely had to shift well before the brake zone. On the front straight I just sort of let it coast into the braking zone instead of shifting to 6th for a second and a half. Since i'm not racing, those extra few mph dont mean much to me. Im not sure what redline in 5th is though.

I don't blame you for going easy in that corner(southbend). its a tough corner because its somewhat off camber and drops right as you apex.

 

[Grinder34]

I couldnt get my home-brew ducts to work very well, especially on the passenger's side (thanks to the stupid header). I probably could have really squeezed it in there, but the duct would be pretty oblong and pressing hard against the O2 sensor. I gave in and bought a set of RooDucts. I figure i'd spent so much on making my brakes already, an extra $200 to make them rock solid on a track was worth it. I plan on painting them, and then wrapping the passenger side, near the header, with heat reflective tape.

I'll post up a how-to when they come in and I install them!

 

[Boogieman98]

I have been thinking on what to do about cooling for my brakes since I had to have the dealer replace my blue spotted rotors because they got to hot. Those rooducts look to be the answer. Where did you buy them?

 

[Grinder34]

I dont think anyone sells them except Randy himself.

http://rooducts.randyzimmer.com/?page_id=144

You send him a check and he sends you a set. They're 3d-printed so he can get them out the door pretty quickly once you say go. I was really hoping to go the home-brew route, but I ran out of energy. People have had good luck with hacking up the Z06 ducts, and my driver's side idea worked well. But I'm to the point where I want something that works well on both sides, and is relatively easy.

I'll be sure to post up a how-to when I'm done.

 

[finallymysti]

I run the roo duct with no heat tape and have had no problems fyi

 

[Batmobile_Engage]

I couldnt get my home-brew ducts to work very well, especially on the passenger's side (thanks to the stupid header). I probably could have really squeezed it in there, but the duct would be pretty oblong and pressing hard against the O2 sensor. I gave in and bought a set of RooDucts. I figure i'd spent so much on making my brakes already, an extra $200 to make them rock solid on a track was worth it. I plan on painting them, and then wrapping the passenger side, near the header, with heat reflective tape.

I'll post up a how-to when they come in and I install them!

If you have a large front splitter and/or engine undertray, you could put naca ducts in them,
basically, drawing air from under the car, and attach a hose inside. I saw that done on a Subie
today when I was surfing the web.

 

[Grinder34]

Im friends with a guy with an STI who had that. At my last track weekend he had just made the switch to RooDucts and he noticed a significant improvement over the under-mounted NACA.

 

[Batmobile_Engage]

Cool, I just figured I should mention it, in case it could possibly be of some use.

 

[Panchosti208]

Now Thats a nice car

 

[Spamby]

Any updates? How's that bbk treating you? Did you ever get the ducts installed ?

 

[Grinder34]

I've been super lazy and unproductive. The roo ducts are sitting in a box un-installed. I bought a house, which has pretty much taken the time and money i used to put into the car. I'm sure that'll change in a few months.

The BBK was awesome at the track in terms of fade--none. I was flying around there and had no worries about overheating. I did get some pad knockback, i'm pretty sure. At the end of the straights, the first press on the brakes felt like "oh god the brakes arent going to work" but the second pump was solid with great feedback. I dont know why I should be getting so much knockback unless my bearings are going or something along those lines. Since i had no knockback with the Brembos its surprising i have it with the Stoptechs. If anyone has any ideas as to causes/fixes, I'd love to hear them!

 

[Alin]

That makes two of us about being lazy! To some degree anyways! :tard:

Also what exactly is pad knockback??

 

[IGOTASTi]

That makes two of us about being lazy! To some degree anyways! :tard:

Also what exactly is pad knockback??

I think he means chatter.

Do you Grinder?

 

[Grinder34]

no, pad knockback.

If i get motivation I'll start a thread on it.

Here's a picture:

Basically, its when the rotor goes at an angle compared to the calipers, and pushes the pistons in just a little bit. The next time you press on the brakes it has some dead space so the pedal gives you that "oh shit" feeling (think of the feel after changing pads).

 

[Alin]

Oh shit dude. My car has that pushy oh shit feeling every time my rotors are wet!! After a car wash or after drifting in the snow. Does that have anything to do with pad knockback or is that something else? Also how do you correct pad knockback??

 

[Batmobile_Engage]

That's somethig else. My brakes are useless for the first second of braking after the car wash too.

 

[Alin]

That's somethig else. My brakes are useless for the first second of braking after the car wash too.

So what happens that it does that?