DE questions

[MikeB]

Completed my first DE a few weeks ago and have some more questions. I am determined to follow others' advice and keep the car mods (stock 85 coupe) to a minimum and spend the money of safety, track time, and instruction. However...

1) At the end of the first session my brakes were fading. By the end of the day I was to the point where I probably would not have gone onto the track, they had faded that badly. Brake fluid was fresh DOT 3 (I know...) and I have now changed to Valvoline DOT 4 (boiling temps close to ATE). I noted that the clear fluid I put in, came out 1 week later as a light honey color. Anyway, I want to keep things as stock as possible for now and looking for ideas to eliminate the fade. I am thinking a Cool Brake Kit might help. I saw Chuck's thread on Baby Reds, but I don't recall a report as to how well his homemade cool kit worked on the track. Or, will a better pad help more?

2). My instructor would double clutch downshift from 4th into 2nd for the hairpin. I like the idea of eliminating a gear change, but not sure if this is hard on the transmission or if double clutching makes it ok.

3). New Konis=lift kit. Sheesh, after installing my new Koni's, my ride height would rival a mini truck. 27 1/2" to top of fenders! Probably a good 4 inches above the rear tires. This is after putting about 100 miles on the car hoping to settle it down a little. And I thought that the t bars held the car up and dampers were to, uh, dampen the ride. Anyway, I will be lowering the car back down this weekend. I suppose that I need to get it aligned and corner balanced, but I hate to do this until I am ready for suspension upgrades. I probably don't have a choice; any thoughts?

A final observation. Stock cars are few and far between at these events and are easy to spot. Lots of roll and dive, squealing tires, etc. I am still going to hold off on mods and spend the $$ driving, but the temptation...

[Randy W]

Mike it sounds like your on the right track - lowering it would be a good first step (try 24 1/2" front and rear). Removing the brake shields will help, if you haven't already done this. The Cool brake kit will further help. The other thing to consider is braking earlier and smoother - this will upset the car less and allow the tires to help brake the car (since these are what really slows the car down anyway).

The transmission should not be used to slow the car. It is much more expensive to service than brakes.

As you have discovered, seat time is the best solution, along with good tires and an alignment. There will always be something to improve on these cars. Only problem is, one improvement reveals three others!

[Jack Olsen]

Pads, fluid and cooling ducts are a great start -- unless the track you're on is tremendously hard on brakes, or you're relying on braking too much as you learn to drive the track, then I'd guess you'll be fine. Carrera brakes are pretty great brakes.

Ride height (especially coming from 27.5) will make a pronounced difference.

The agonizing moment with upgrades comes when you do them -- and your lap times improve -- and then some guy in a bone stock version of your same model comes along and blows you out of the water.

You're instincts are dead on the money. Patience and practice will do you more good than anything else.

(Hey, do as I say, not as I do, okay? )

[MikeB]

Randy
Thanks
My instructor downshifted from 4th to 2nd not to slow the car, but to be in the proper gear coming out of the turn. He pointed out that even the most experienced drivers have difficulty holding constant brake pedal pressure while rolling the foot to heel and toe. I know I do...

So... at this stage, Cool Brake first, pads second?
Alignment only or alignment with corner balance?
If I take her down to 24 1/2", will anything else need to be changed, like raising the steering rack?
Also, my tires suck. Michelin Pilots XGT H4. Treadwear rating of 400. 225 and 205/16. I am ready to ditch these already, but I figure they are a great teacher.

[Randy W]

Mike, if you can, do both at the same time. An alignment is best done with a weight balance (your weight in the driver's seat). Be sure to tell them you want a street/track alignment. The tires can wait, until you have tried everything and become really frustrated that the car will not do what you want it to do - this same guidline can carry you through all the other changes you may want to make to the car.

[MikeB]

Jack
I am here to tell all that a 27.5 ride height is no fun. My beautifully handling car (even with a bad damper) has gone away, replaced with a darty, twitchy beast with a mind of its own. Like teflon on ice.

And, my instructor just missed turning in TTOD in his 72 S.
Against highly modified cars, an F355 Ferrari, and so on. He got blown away on the straights (stock 2.4), but he is unbelievable in the turns (fully mod suspension, Toyo's, etc.). A great guy, too.

Of course, I will never forgive him for hooking me on this...

[DonNewton]

Mike,
If you're serious about lowering your lap times, good tires are the way to go. CAVEAT: If you're fairly experienced! A novice (sorry, but true) driver will hide myriad mistakes with DOT approved "race" tires. Your instincts about using the tires as a great teacher are dead on. Once you've learned all you can from them (how they react to different pressures, alignment conditions, extreme ride heights, etc), and they are absolutely ready for the trash heap (about 5 track sessions, unless corded), then move to different tires.
Now, the fun (expensive) part. You really should invest in a set of track wheels to match your new track tires. This means that you'll also have to replace your current street tires, because you ran them down to the cords, and you're buying new DOT "race" tires, and "Really honey, these new (fill in the blank) tires will wear out very quickly if I drive them on the street, so I need new wheels to ensure their life expectancy." Yeah, never worked for me either. . .
Don't be too rash in investing in highly touted go-fast items. The fastest item lies between your ears and that part that is planted in the seat. Once you overcome those two disconnects, you'll be much faster.
At least, that's what I've heard.

Don Newton
Chief Instructor
Potomac Region, PCA

[MikeB]

Don

Agreed. I suspect that after the Pilots wear out (will they ever, with a 400 rating? , I will be looking to do a little better. The nearest DE track is about 200 miles away, so I am debating whether to used a roof rack or, gasp, a small trailer. I never, ever, dreamed I would even consider pulling a trailer behind a 911, but a lot of track people are doing so. The sight of a TT pulling a trailer is, well, words fail me now.

[Jack Olsen]

The rack is cheaper, and it doesn't mean being limited to 55 mph on freeways (not that that stops the trailer-pulling guys on this board). I'd follow Don's advice, though, and not rush in to tires that will provide an irresistable crutch, but also mask your other shortcomings, and break lookse in a hurry when you push them the wrong way. Lower the car, get the brakes under control, and drive it for a season. Then you'll have a real baseline to compare it to next year when you've got coil-overs, Hoosiers and ceramic brake rotors.

[stuartj]

Remember more aggressive pads mean more heat in the braking system. The wee little rotors on our older cars can only take so much....I went to Pagid black and orange- unbelievable difference for three laps - then heat warped the rotors. Recommend a vent kit - looking for a good on meself. Also, you can chew through many sets of standard pads for the price of Pagids, and they may be kinder to the standard rotors in the end.

As you point out, no good doing a proper alignment till you address the ride height and springs/bars/shocks. Like many, I have discovered for myself, 911s are very vulnerable to geometery, especially in the rear and this is amplified/exagerated by weight transfer.

As for the double clutching down, good heel/toe should allow either a smooth 4-3-2 or 4-2 shift, without any time in angel gear which is required when double declucthing. Goes to the school of "give yourself the least number of things to do" driving. I am sure there is good reason to double clutch down, but in a synchro box, I am unsure what they are.

Tyres next. Enjoy your porker.

[orbmedia]

MikeB,

You're definately on the right track. Your car doesn't need brakes, you just need to use them less (and properly). Get good racing pads (I like the Cool Kevlar variety) and use Ate Blue fluid or equivalent. Then have your instructor teach you how to use the brakes properly so you don't overstress them.

Remember that the stock PCA racing Carreras are required to use the stock caliper/rotor setup ad their laptimes are *blistering*. If they don't need brakes you don't either.

[MikeB]

Orb
Thanks for the input. You and Randy both say to use less brake. I understand what you are saying, but I don't know if my instructor can help on this. My first laps on the track were with him and in his car. I will confess, he scared the hell out of me. Deep into the brake zone, hard, hard on the brakes. Or, at least I thought he was hard on the brakes. Having never experienced this before, maybe he wasn't. Hmm, lots to learn.

I am very encouraged about your comments on the stock cars turning in hot laps. I am having a blast so far at DE/ AutoX, but I see lots of people throwing in gobs of money at their cars in an effort to go quicker.

Now if I could just find someplace to practice...

[patalive]

I second the advice from DonN, JackO and Orb. I have had Don as an instructor, he knows what he is talking about! (Hi Don )
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When I started doing DEs several years ago, I was told by the pros to leave my car stock for the entire first year, except brake pads. The advice was learn how to drive, drive the line, and BRAKE PROPERLY. Learn car control, learn feedback from your car and your stock tires. Learn to drive consistently and, most important, DRIVE SMOOTHLY. It is often said that your stock Porsche has so much more potential for going fast than you have ability to drive at its limit. The trick is to bring your ability up to the car's potential (in its stock form) and then begin making mods.
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And some of the first mods you need to consider are safety related. Going into my second year, I changed over to track tires, got brake coolers AND installed harness truss and harnesses. The truss and harnesses significantly improved my times - they allowed me to concentrate on driving the corners rather than hanging on for dear life. With your butt planted firmly in the seat, you better feel what your car is doing. Plus, of course, they provide a margin of safety over 3 points.
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After a season and a half, I placed 4th in class at the time trials at Summit Point with no mods to the suspension. OK I did add SSIs and two-out exhaust. But my point is I learned to drive the course and my car in its stock form. And by the way, I am not a young racing kid - I did this when I was 57!
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As the pros say, you will be a faster driver by spending money on seat time, not car mods!
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Chuck
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[MikeB]

Chuck

The brake coolers you wrote about, are you talking about a Cool Brake kit? If so, would you do it again?

Mike

[chuckr]

Mike,
I'd suggest getting the ride height and corner balance done now, this will give you much better feel and handling.You can do DE's at TWS on srteet tires for the green run group,you are getting really good advice here,you are on the right track.Between the Austin and Houston and Dallas clubs you can have an opportunity to do DE's almost every month.I work for Scotts ******** in Gerogetown, you might have seen our cars on the track at TWS, we do track prep and have customers from all over Texas,if you do not have a good shop give us a call
512-930-1238 be glad to have a look and see where you are.
Good Luck !

Chuck

[patalive]

Hi Mike - -
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Yes, they are the Cool Brake Kit, but I purchased them used from a local guy here who totaled his white Targa. There are apparently conflicting reports on the benefits - my mechanic says they provide some benificial cooling air to the rotors but not as much as the manufactures would have you believe. They collect cooling air under the car, where the air flow is broken. The better solution is to duct air from the vents through the front spoiler.
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I think the Cool Brakes do provide benefit - interestingly, after I installed the coolers, the front wheels had considerably less brake dust than the rears, indicating that air, flowing throught the coolers, were blowing the dust out before it could land on the wheel.
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Yeah, I would do it again. I did experience less fad at the end of the day. Makes threshold braking (maximum braking just before lockup) a bit easier since braking action is more predictable and consistant. -

Chuck

[jluetjen]

Mike
Just a couple of thoughts on your question #2 and braking.

You said: "2). My instructor would double clutch downshift from 4th into 2nd for the hairpin. I like the idea of eliminating a gear change, but not sure if this is hard on the transmission or if double clutching makes it ok. "

The answer is "It depends on your driving style". Here are the rationals for the different answer. Note that the engine is NEVER used for braking. They used to do that in the dark ages when a race car's brakes were awful. Nowadays the brakes are far superior to the engine's ability to accelerate it. So there is no reason to use the engine for braking. Using the engine to slow the car will also upset the braking balance. Generally downshifting is done at the end of the braking zone prior to turning in. People often have the idea that they should start downshifting as soon as they start breaking, and that just makes the whole process more difficult. For example, imagine a 100 yard long breaking zone. If you try to downshift 1 gear every 25 yards, you will find that it is virtually impossible not have the engine slow the car, which makes it almost impossible to successfully modulate the braking. Rather try to do all of the downshifting in the last 25 to 35 yards of the braking zone

1) Downshift through each gear. If you have a sequential gearbox this is a given. If you look at the number of motions that you have to complete to double-clutch, partial double-clutch or just single clutch each gear, you are going to be very busy going from 5th to 2nd. Doing it this way does somewhat reduce the risk of over-rev'ing the motor when downshifting since you're only going down one gear at a time. Balance that against the risk of getting one of the many motions wrong.

2) Skip gears or go directly to the ultimate gear. This is the method recommended by Jackie Stewart and Alain Prost. Skipping a gear means to 5 to 3 and then to 2. Otherwise, you could also just go directly from 5 to 2. When doing this you do need to be sure to find the right gear so that you don't spin the motor. If you are trying to go from 5 to 3, and you get 1 instead. You will kill your motor and most likely spin. On the other hand, skipping gears simplifies the tasks required to complete at the end of the braking zone.

Double clutching is a separate style decision. There are 4 choices: Full double clutch, partial double clutch, single clutching and no-clutching.

Double clutch: You clutch out of the higher gear into neutral, release the clutch and clutch again when going into the lower gear all while squeezing the throttle to match the rev's. You need to be threshold braking while doing this.

Partial Double Clutch: Don't use the clutch to get out of the higher gear, just shift to neutral, and then use the remaining double clutch process. The effect is the same, but it is simpler.

Single Clutch: Push in the clutch, shift to the next gear and release the clutch. All while braking and matching rev's.

No Clutch: Slip the car out of gear, match rev's with the throttle and lightly slip the lever into the next gear - all while braking.

Ultimately, the correct option is the one that you are most comfortable and smooth with. I've heard of fast drivers using all of them. Finally, when it comes to braking and your comment about finishing the DE with almost no brakes. It reminds me of a story I once heard about a team mate of Fangio's asking him how he drives so fast. Fangio pointed at the drivers right foot and said "More gas. Less Brake". How were your times at the end of the DE compared to the beginning? You might be surprised to learn that you were as fast if not faster in your car when you couldn't use the brakes. I know that I was once when I had to finish a race with non-existant pads. I had to adust my style so that I was braking lighter and rolling more speed into the turns. It turns out I was regularly over using the brakes! Less brakes = more speed! It sounds kind of obvious when you think about it.

Since that time I've tried to avoid being the "King of the Late Brakers!"

[Randy W]

Great post, John. The only thing I might be able to add is about braking. If you think about your tires/road and pads/rotors as similar sufaces during a braking event, it may help to understand the forces that are generated during this event and their effect on the surfaces being asked to slow the car. If your very initial braking is done earlier and more smoothly/gently, those surfaces (tires and pads) will be less distorted by the weight transfer and the forces that you are initially applying. Now, that these surfaces have been prepared without being asked to do too much, you can apply a stonger and stronger force (with a gradually increasing weight transfer) to the point of threshold braking. This will give you maximum braking ability without the need for maximum braking. Remember to release the brakes smoothly as well, to not upset the car during turn in. When you first try this, plan to brake earlier than where you may have before. As you become more proficient with this, you may find that you are starting your braking in roughly the same spot as before but getting much better results.

[Don Wohlfarth]

Change your brake fluid. I know you have just changed it. Change it again as this will act as a flush. You may not know the last time the PO changed the fluid. Brake fluid is cheap. Will also allow you to be comfortable bleeding brakes if you experience brake fade in the future. While changing brake fluid take a good look at your rubber brake lines. If they have never been changed, now would be a good time to do that. Brake lines are cheap. For an everyday car I would not change to the braided lines but continue to use rubber.
Hard to believe that changing shocks would raise ride height 2 ".
When you change the ride height you will benefit from corner balancing and 4 wheel alignment. When you change the ride height you could get lucky and have the correct weight on each wheel with the same chances as hitting the lottery.
With your stage of experience I would stay with existing brake pads if they are in decent shape. If you have half dozen DE days it would probably be a benefit to change to a more aggressive pad. As long as car is mostly street driven do not go to an all out race pad as they need more heat to work properly than you can generate on the street. Race pads for ax will slow your times down as well.
The longer you stay on street rubber the better in the respect that you will learn to drive the car. Take the time to learn to drive what you have. Your goal should be to learn to be smooth and to have repeatable lap times. Learn from a stable platform instead of trying to improve from constantly changing improvements. It's pretty easy to fall into the trap of being a average driver in a very fast car instead of being a very good driver in a average car.
Spend your money on the most important part and that's improving the driver.

[widebody911]

I have the OG Racing brake cooling kit (the fiberglass one) and it does work. I have the scoops on the a-arms, but plan to get a front bumper with holes, at which point I'll re-route the hoses.

At the last DE I did, I had no brake fade, nor did the instructor who drove my car like a bat outta hell.

For street driving, the cooling scoops are just one more thing to worry about getting knocked off.