In the last 2 races and my Comp School day, I noticed that my brake pedal would start getting stiff and the braking power would start to fade away. Not like pushing it to the floor and nothing happening like when you cook your fluids, but the brakes just wouldn't have the stopping power. If I went easy on the brakes for a lap, then got on them again, they would have a little power back temporarily.

So my thoughts are that either (a) the July heat just affected it and I need brake cooling ducts, or (b) since I have switched to a smaller 14" wheel with much thicker "spokes", that maybe the pads weren't getting the cooling that they were with my previous 15" Rota Circuit 8's. The Circuit 8 has very thin spokes - the amount of raw area you can visibly see of the rotor and brakes is like 50% more on the 15" Rota's then the 14" Panasports. Is it possible that the brakes are having more trouble getting cooled now, coupled with the hot July weather?

I don't currently have brake cooling ducts because I've never had any fade before. I obviously need to install some regardless of if the wheels make a difference.

 

Yes, it is very possible the new wheels are restricting airflow over the brakes. Ducts should help this problem. Or wheels with better airflow.

 

Yes, wheels make a difference. Witness the 5 spoke "spinning star" wheels on older M5's. They act like fan blades.

Some rally cars have wheels that do this to. I think Compomotive still makes some with a pattern that works.

Warren

 

Okay good - I wasn't just inventing stupid theories again

Unforunately, the Panasport 14x7 really is THE wheel to have in ITA from what I have learned. I'll just have to add some brake ducts and hope for the best!

Anyone have thoughts on brake cooling ducts with a roadracegear.com spliter/air-dam? I'm not clear on how it attaches to the front bumper and where the brake ducts would be.

 

It's important to make the distinction between fluid fade (mushy pedal) and pad fade (firm pedal, no brakes) - sounds like you were getting the latter. It results when the pad material gets overheated and the coefficient of friction between it and the rotor goes way down. You might try different compounds to see if one works better in hot conditions but ducting is your best bet, all the way 'round.

Kirk

 

Thanks Kirk, I agree completely.

And I think I just answered my own question about the splitter/air-dam. I'm assuming in this pic that it starts where the black painted piece is? And in this case you can see exactly where he (Fowler) put the brake-duct intakes. (notice also the use of 14x7 Panasports, heh) So maybe I'll just do it like that

 

My bumper does not have those indentions where the brake ducts are run from on the above picture of the CRX. Who is the roadracegear.com guy here?

 

"JohnW"

 

The wheels also can act as heat sinks, a wheel with more sufface area will desipate more heat than a wheel with less sufface area.

 

What pads are you currently running?

Brake ducts are never a bad idea, but you may have a simpler solution with upgrading to a hotter pad.

Gary
Sheehan Motor Racing
http://www.teamSMR.com

 

That bumper cover is from a 91 CRX Si. I just put one onto my CRX so that I can run ducts like that too.

 

Same question - what are you currently running for pads.

I see alot of people running low temp showroom stock racing pads like Hawk Blues, and eventually if you get using a typical Honda/Acura hard enough that's just not going to cut it without lots of rotor mass and pretty good ventilation.

Consider running something like a Hawk HT-10 or HT-15 (300-1600 degrees).

I only know what I've run, so mine is not the last word. I'm sure that one of the boards favorite brake gurus can assess your needs and put you into a compound that leaves you some room at the top of the heat range.

Scott, who thinks the brake pedal is the second most ergonomically important device in the cockpit...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike P. &raquo;</TD></TR><TR><TD CLASS="quote">"JohnW"</TD></TR></TABLE>

thank you sir

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 57STS &raquo;</TD></TR><TR><TD CLASS="quote">The wheels also can act as heat sinks, a wheel with more sufface area will desipate more heat than a wheel with less sufface area</TD></TR></TABLE>

Interesting, I've never heard of that. I'd heard that about larger rotors though

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JHill &raquo;</TD></TR><TR><TD CLASS="quote">That bumper cover is from a 91 CRX Si. I just put one onto my CRX so that I can run ducts like that too</TD></TR></TABLE>

Hmmm, then this is probably a GCR question, but would a bumper cover from a CRX legaly go on my hatchback from the same model years? I've been told it would indeed fit right up, so it's just a matter of legality. Not that I can't just cut some holes in my existing bumper cover, but the CRX bumper looks much more pimpy for the ducting.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GarySheehan &raquo;</TD></TR><TR><TD CLASS="quote">What pads are you currently running?</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Same question - what are you currently running for pads.

Consider running something like a Hawk HT-10 or HT-15 (300-1600 degrees).
</TD></TR></TABLE>

I've never looked into temp ratings on pads, didn't even know that was something to look for - thanks for the info. To answer both of you, I've been running the Carbotech XP... not the very latest compound, but the one before it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I only know what I've run, so mine is not the last word. I'm sure that one of the boards favorite brake gurus can assess your needs and put you into a compound that leaves you some room at the top of the heat range. </TD></TR></TABLE>

heh, no doubt about it
MaddMatt, you want to chime in here?

 

Hi Ben,

Congrats on your first WIN a couple weekends back.

IMO- Try to run ducts to 'natural' openings in the bumper cover. Tom Fowler (as seen in the pic) uses the 'factory fog light hole' in his 91 CRX. Phat-S (Adam R.) cut holes under the front turn signals on his 88 CRX... both work well. Adam had some pics here not too long ago.

RRG (me) did try a Air-dam with holes included in 1999. It can be done, however 2x 3-inch holes is 6 inches less downforce on the front of you car. I could never prove this didn't work on the stop watch.... but it wasn't worth the time and effort to do it this way. It made the A-D weaker and could cause major problems if the A-D should make contact with something.


If possible, I think the best way to include ducts is to mount them to the radiator support. I did this with the 87 Civic and my new car. Check out the link bellow or on the opening page of my site. http://www.roadracegear.com The ducts are pointed into a 'natural' opening and require no reinstalling for trailer/ splitter issues.

http://www.roadracegear.com/images/rrg_civic6a.jpg

BTW- PADS!!!! BRAKE PADS!!!!! See my signature!!

Love em' 1109s. 20 laps at Summit with 120 degree track temps and ZERO fade.

Good luck.

 

Hey Ben. If I remember my days of thermo correctly (and I may not, it's been 10+ years!!) the difference in the air temp from the spring to now is going to have a minimal effect on cooling. Initially is sounds to me to be related to reduced airflow from a smaller wheel, as many have already said.

Ducting. Do it.

Matt

BTW, congrats on your first win!!!

 

thanks guys - ducting and 1109's.... easy enough

 

You might wanna check this out, just for kicks&gt;&gt;&gt;&gt;

http://www.sbmsinc.com/race_shop.html

This is Tom Blaney's site. I'm working on a 89 CRX si, and just ordered his brake cooling ducts, adapters, and air dam. The air dam goes on with 4 dzus fastners over the factory cover. 100 percent ITA legal. It's a plastic piece and can be trimmed for the foglamp holes (Brake duct holes). It also extends under the car which holds the brake ducts up from damage during John Deere excursions.

I haven't put my hands on it yet, but I ordered the 91 CRX si cover. That's what Jim just bought, and I believe he said that 91's the only year with the fog light indent.

 

I second the Hawk HT-10's. We've been using them on the rears of the WRX for years. We run a Pagid RS-14 on the fronts now, which have been awesome, but we're switching to PFC 97's.

Gary
Sheehan Motor Racing
http://www.teamSMR.com

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GarySheehan &raquo;</TD></TR><TR><TD CLASS="quote">I second the Hawk HT-10's. We've been using them on the rears of the WRX for years. We run a Pagid RS-14 on the fronts now, which have been awesome, but we're switching to PFC 97's.

Gary
Sheehan Motor Racing
http://www.teamSMR.com</TD></TR></TABLE>

Any particular reason for the switch to PFC and the 97 compound in particular?