Brake biasing and Hawk pad torque confusion

#1

Just found out something interesting about Hawk pads that I thought might be of general interest. I’ve been exploring brake biasing because I can’t trailbrake* my car to save my life. I did my DE’s in a 911 and in the right hands trailbraking a 911 was a thing of beauty. Even if in my hands trailbraking 911 was sometimes a thing of spins.

So I’ve been talking to folks about pad combinations that would give me a little more bite in rear. And couple of apparently knowledgeable retailers have told me that I should try HT10’s in front and Blue 9012’s in the rear. They were telling me that the Blue 9012 compound provides more braking torque then the HT10 compound, particularly at lower temps…perfect for adding rear brake bias.

Hawk’s website is ambiguous about the relative braking torque between the HT10 “Intermediate to High” and the Blue 9012 “Medium/High Torque”. How do you compare “Intermediate” to “Medium”?

Here’s the fun fact. Apparently the common wisdom and website are both wrong. The Hawk engineer I just talked to said that the 9012 Blues have LESS, not more, braking torque then the HT10. Further, that the website is supposed to say “Blue 9012 Low-Intermediate Torque, Medium-High Temperature”.

It goes without saying that it would be unkind for anyone to use this information beat me worse. I’m already last. If you end up using this information, you are morally obligated to sit your ass in my passenger seat at CMP and show me why the front runners are 6secs faster then me.

*definitions of trailbraking differ. I’m using it to mean using the brakes to get a little additional rotation around turn-in.

#2

Ranger wrote:

[quote]If you end up using this information, you are morally obligated to sit your ass in my passenger seat at CMP and show me why the front runners are 6secs faster then me.
[/quote]

Shouldn’t we swap seats for that to happen? :wink:

#3

Gasman wrote:

[quote]Ranger wrote:

[quote]If you end up using this information, you are morally obligated to sit your ass in my passenger seat at CMP and show me why the front runners are 6secs faster then me.
[/quote]

Shouldn’t we swap seats for that to happen? ;)[/quote]

Lol, I don’t care how it happens. Tie me to the hood if that’s what is required to show me what I’m doing poorly at CMP.

#4

Don’t be so hard on yourself…you’ll get it. Contrary to popular belief, there is a pretty large learning curve the first year.

#5

This is what I run, HT-10 front and blues rear. I don’t like HT-10s all the way around I find that the rear is too loose with trail braking but if you are trying to get it to rotate more then try the HT-10’s all the way around, I know some people on this board run HT-10’s all the way around but it doesn’t suit my driving style.

#6

I run the 10/Blue setup, but I’m getting ready to try the 10/10 set up.

Scott - Watch some of the videos people have posted or post some of yours for comments. Most of the differences will jump out at you.

#7

I currently have HT10’s all around and the braking balance is better then the last experiment. I’ve not yet used them at Roebling tho, and that is really my testing ground. I think that Sunday will be a good test day. Tomorrow and Saturday I’m going to be slogging thru the rain.

Note tho that what I want to try is additional rear brake bias, not equal rear brake bias. Porsche late model 911s are biased towards the front. So folks put high torque pads on the rear to compensate.

So maybe BMW did the same thing with our OEM bias. And that’s what I’m going to experiment with…rear biased brakes. Make that car squat at the onset of braking so the car’s weight isn’t thrown forward so dramatically.

After more research today I figured out that it can be done with Ferodo pads. Couldn’t do it with Hawk because HT14’s aren’t made for the E30 rear.

Re. the videos. I watched the CMP vids carefully, but all I really saw was better precision on the slow corners and a different line on turn 5 that I need to try. I’m sure that there’s guys that can pull additional subtlties from the videos, but without the data to study, it’s hard to extract nuances from the video.

I can’t look at the video and spot how and where guys are getting a little additional rotation (via trailbraking or throttle-lift oversteer), or the other million differences between sucks and skills.

#8

Scott, I just can’t resist asking, why are you so convinced the issue is trail braking after one event? May I suggest, a rear engine car is going to behave radically different than an e30?

#9

Make sure you are listening to the videos as well. You can pick up a lot as to when people are picking up and letting off of the throttle. Turns 8&3 in particular are great places to listen. Also check out how fast people are entering the turn 4-5 complex.

#10

Scott, reading your thread again, start thinking in terms of your ability to throttle steer more than your ability to trail brake.

#11

Gasman wrote:

I’ve created some confusion. I’ve ~20 days in the E30, having bought it last fall. I knew that the front engine car would drive differently, but I was still surprised by just how different the E30 is. You have to be cautious going into a turn in a 911, but our E30’s can just fly into turns. But geez how the 911 can get on the throttle hard and early in a turn.

I was just starting to figure out trailbraking in the 911, and then I got the E30 and suddenly couldn’t do it to save my life. And until I experiment with brake bias a bit, I won’t have an idea how much is bias and how much is driver suckage.

I acknowledge that other setup issues could be impacting this, but one variable at a time.

Throttle steer is working for me (trailing throttle oversteer), but it hurts to do an abrupt lift in order to induce a little rotation. I gotta find a way to rotate without lifting the throttle. Of course there’s throttle-on oversteer, but that’s something I’ve not really worked on.

Years from now you’ll be able to say that you all knew Ranger Gress when he was just starting out. He had some special brake pad combo that allowed him to do trailbraking 720 spin heading into a turn. And you haven’t tried to execute a pass until you’ve tried to divebomb RangerGress while he was doing one of his defensive 720 moves.

And if it’s a crappy idea, I just swap out the rear pads. But somebody has to do the experiment.

I’m watching Setup as I type this. Hunt’s getting lots of camera time because of his enthusiam. Skeen’s not getting much airtime. I think it’s because he’s too normal for reality tv. Not knowing the first thing about reality tv, it seems that it’s the absurd guys that get the air time.

#12

He got quite a bit of air time towards the end. It even seems that TK may be a little sweet on him…

Try using the left foot to induce rotation instead of and abrupt lift of the throttle. Sometimes it doesn’t induce rotation so much as it minimizes understeer. I use this a good bit in T5-7 at CMP and T6-7 at RRR.

#13

155MPH wrote:

[quote]He got quite a bit of air time towards the end. It even seems that TK may be a little sweet on him…

Try using the left foot to induce rotation instead of and abrupt lift of the throttle. Sometimes it doesn’t induce rotation so much as it minimizes understeer. I use this a good bit in T5-7 at CMP and T6-7 at RRR.[/quote]

You mean a touch of left foot braking well after turn-in to create a sudden reduction of understeer? Wow, I’d have to think about that a bit. It would throw weight forward, but it would also increase the lateral force on the front tires. Interesting. Anyone else want to weigh in on that idea? Or maybe I misunderstood.

#14

I wouldn’t call it sudden, but yes, that is what I’m talking about.

#15

For what it’s worth (which means not much, seeing as how I have only raced 3 weekends!), I switched over to 10’s all the way around for the exact same reason (easier rotation) and it has made a huge difference. I previously tried both stock brakes on the rear and HP+'s.

As for general advice from a fellow rookie, I would focus more on learning the characteristics of the car at different tracks and in different types of corners before you start making too many adjustments. I picked up 4-5 seconds at CMP (my first time there in a fully prepped SpecE30) just by listening to our fellow racers and following a few of them on the track. Travis helped me a lot in Turn 8 and Skeen provided some helpful advice in a few other areas of the track.

#16

155MPH wrote:

[quote]He got quite a bit of air time towards the end. It even seems that TK may be a little sweet on him…

Try using the left foot to induce rotation instead of and abrupt lift of the throttle. Sometimes it doesn’t induce rotation so much as it minimizes understeer. I use this a good bit in T5-7 at CMP and T6-7 at RRR.[/quote]

Today the weather was nice at Roebling so we got in good sessions. The Blacks really do exist and are very nice. Yee seems firmly resolved to change his name to Chi, no matter how much that might disorient his buddies.

The rotation test of the HT-10’s (all around) was interesting. It definately worked better for me then the previous idea. So the rotation under braking works with this pad combo, I just have to get better at it. Fortunately I dropped passenger Natalie Black off a couple laps before I trailbraked myself into a 360deg on turn 5.

After thinking about what 155mph said about using the brake pedal to shift weight forward and combat understeer I tried to work on that. Left foot braking is a bridge too far, but I did experiment with gentle braking (well) beyond turn-in. That is to say, Instead of braking hard and then turn in, I hit the brakes moderately, went in with a little too much speed and gently stayed on the brakes until I’d made a good fraction of the distance to the apex.

Note that I don’t mean trailbraking. I wasn’t trying to induce yaw via increased rear slip angle. I was trying to increase yaw via reduced front slip angle.

And it was interesting. I could see how it was a handy tool to have in one’s toolbag. It definately reduced understeer early in the turn. Will have to experiment with that more.

Finally, I found that I’m slow. I was getting fast enough at Roebling (low 1:26’s), that I was starting to get a little cocky. But today I was clumsy and slow. So now there’s perfect symmetry in that I suck everywhere. Shit.

Gonna have to unscrew myself at Roebling. Can’t suck at my home track. Can’t.

#17

Ranger wrote:

Sure. Fine. Have all the fun without me! :stuck_out_tongue:

#18

“Gonna have to unscrew myself at Roebling. Can’t suck at my home track. Can’t.”

You don’t suck at Roebling. Like Steve says, don’t be so hard on yourself. You ran away from me and I felt like I was going pretty fast. Sure our times were slow vs. the track records but you were the fastest Spec E30 (on Sunday anyway) car there. Maybe the track was slow because of the rain Fri and/or cool (realtively) temps.

Don

#19

I just glanced through this thread but has anyone mentioned tire pressures?

Carter

#20

I played around with mine a bit over this past weekend at Roebling trying to get them to 38 PSI hot. I was a bit surprised to see that the right side stayed right in line with the left. I expeceted the lefts to grow more.