malcolmd

I've been away from the forum for a while......but what better way to return than to talk about my latest (and second) track day. For those that don't recall, I upgraded the car with the UMW Stage 2 K16/26, ECU & 130mm 100 Cell Cats, with PSS9's as the only suspension upgrade. My track experience is very limited, and clearly I'm the weak link in the package! As you can see in the video, I've mastered the art of planting the right foot, but the rest of it needs work. BTW, the UMW Stage 2 is fantastic for this sort of track work. Great torque and flexibility. Couldn't be happier. Thanks to Kevin.

On Sunday I had several firsts. My first experience with Queensland Raceway with the local Porsche club, my first use of a new Performance Box, and my first dabble with on-board video. So I hope you will accept my indulgent video contribution....

http://www.youtube.com/watch?v=OELS8-2NKm0

Lots of room for improvement, especially working out braking points and lines. It was great fun, especially as we had to contend with intermittent rain squalls from the nearby cyclone (hurricane).

My fastest lap data is in the atachment. (I'm going to have to work out how to put the attachment where I want it in the text!)

So this brings me to my question. During one of the sessions, I found myself without brake peddle pressure, fortunately in the cool down lap. Apart from learning to briefly tap for brake peddle pressure well out from the corner or perhaps on an exit after heavy braking, I might need to look at better brake cooling options. I have standard brakes & pads and use ATE DOT 4 Super Blue Racing Fluid.

Do any of you have experience or recomendations with regard to air flow, ducting etc?

Cheers and thank for your help.

Malcolm.

mattipuh

fun to see track vids always. your turbo seems to go to 200km/h nice, mine 968 looses acceleration usually after 160km/h.. horsepower.. what is that?

For me first thing that comes to mind is that you spend quite long time on brakes, which can lead that they heat up. I heard one rule of thumb in track driving to be spend as little time on brakes as possible, which means that if you're braking, you should brake with rather full power. this might sound that it would destroy brakes faster, but actually it does not. Having short and powerful braking you brake faster, and heat them up less.

malcolmd

mattipuh, I think it is about 465 to 470 HP. No dyno data, but reparted 100-200 times of mid to high 9's would be consisent.

You make a good point that I have not considered. Because of inexperience, I am breaking too early, but initially hard, but then as it becomes clear that I'm going to pull up early, I then trail the brakes. I think you can see this in the negative log Gs being negative 0.9 for a period but max negative occuring well before the minimum corner speed and ongoing but significantly less negative G for quite a while.
Thanks.

Rassel

Nice putting the car on track!

1.) Make sure you don't drag the brakes. Mediocre braking over a longer time is a no-no. Good that you have a driftbox that can tell you more.
2.) There's a brake duct solution for the 993TT. http://p-car.com/diy/coolingduct/

I think if you let the search engine work for you on Rennlist, you should be satisfied with the result.

Keep us updated!

Spartan

Ditch the super blue and get SRF first and foremost. Second which ever ducting setup you go with make sure it doesn't just throw air at the side of the rotor. It must throw air at the center of rotor to have any effect regardless of whether the rotor is drilled or not. Don't let people tell that is appropriate for a drilled rotor

I have a very very effectivly solution that I used for a season with stock brakes but it only works if your 2wd which I assume your are not.

ScottMellor

How thick are your pads? And how fresh is your brake fluid?
In a similalry set up car (Frank), prior to a track day I would always make sure I had AT LEAST 50% pad and flushed the brake fluid. I never had a soft pedal.

pstoppani

Unless it was extremely hot outside, I'm not seeing anything from your data and video that would indicate a need for more cooling. Also, before considering cooling, you'd be better served by racing pads. The stock pads are fine, but the brakes will run hotter with them since they are not as efficient.

What does your brake fluid look like after the events? Any air bubbles? If yes, then you boiled the fluid. If not, I'd have the brake system checked. Super Blue is fine if you flush it often. I prefer Castrol SRF because it is has a very high wet boiling point so you don't have to flush it nearly as often and it stays consistent.

I have 550+HP and drive the car very hard at the track and have never experienced fade with the SRF and Pagid Yellow pads. I change the SRF at most twice a year; it's that GOOD

Regarding your braking technique, it looks like you start out too light and then press a bit harder at the end; based on your data. Which, oddly enough, is the opposite of what you think your are doing. What you think your are doing is a better technique than what you actually are doing. By starting hard and trailing off, you have better control of the turn in point and you can learn over time that you can brake later. If you start out too light and then have to do a corrective "panic" increased brake pressure, you're more likely to blow the corner entry speed.

To insert your image where you want it in a post, use the image button (but, you have to upload the photo somewhere on the net first and insert the URL of the photo).

DM993tt

big reds are plenty capable to stop these cars. I have done 6+ hrs @ WGI in 1 day stopping only to re- fuel. Never any fade or softness of pedal. Pagid Yellows are will do the trick. This setup is capable of hours of hard braking - I will frequently threshold brake around the 2G level and have never had issue. .

http://www.youtube.com/watch?v=Oef336hA_1U
http://www.vimeo.com/2820636

wagongotya

Easy answer is to brake less but the honest answer is to make sure you're using the right pads, the right fluid and proper ducting. You can still cook your brakes with the proper setup don't get me wrong, but having the right pieces in place will get you a long way.

Ditto what everyone is saying here, big reds are plenty when well executed. Spartan and I run naca ducting up through our belly pans directly into the rotor when the front diff is removed...works like a charm and literally costs less than 100 bucks in parts

hiflexaust

Hi Malcolm,

You are almost running down the slope now! The guys here are right, Dump the blue and go for the SRF. Make sure the brake system is beld 100% and whilst the standard pads will be OK for your first couple of track days, get some Pagid Yellows. The brake distance shortens dramatically and the feel when hot is sublime. I would not be looking for more ducting just yet as I am sure you are not getting your brakes hot enough rather than too hot. They guys that talk of ducting are running big brakes and race pads and are working off proper track braking markers........once you start to get to that stage, then you can start worrying about cooling the brakes. At Eastern Creek, I am still hard on the gas in 4th at the 100mtr marker before standing the car on it's nose at the 75mtr mark prior to turn 2 and yet most guys with street setups are very hard on the brakes at the 150mtr to get it slowed by the corner. Simon has gone to GT3 Cup Car brakes now as he was going thru 2 sets of rotors and multiple pad sets in one year and I have just gone over to the big brakes for the same reason as well. The issue was never that the standard brakes wouldnt do the job, it is just that you can get to a stage where you wear them out very quickly and the cost equals bigger brakes! Let me know when you guys are doing another track day up there.....I would love to come up and have a go in Qld........I have not been on track up there yet.

malcolmd

Thanks for your replies. The usual speedy and helpful 993tt forum support that makes this such a great place to be!

For the record, the pads and fluid were near new (one track day only). Curiously, I had done three 1+5+1 lap sessions without an issue that morning. I did another 4 in the afternoon after bleeding the brakes again without issue.

What I have gathered from all of this is that for the sort of use that I put the car to, which largely are 5 lap sprints with one warm up and one cool down lap, the brakes should be just fine, if I get my technique right, and shift to the "racing red" SRF and consider Pagid yellows.

I have not really considered the art of braking too much before neither have I had the tools to examine it. Pstoppani is clearly correct that I misunderstood what the negative Long G data was telling me. Looking at the appended chart showing four episodes of braking (A-D) is becomes clear that: 1) I brake far too early, 2) The initial application always is not to the max with hesitation followed by a secondary and harder application, 3) Because I have braked too early, I have more time to continue applying brake pressure even though the degree of application late in the cycle is light and tapers off, 4) all of this means the pads remain in contact with the disc generating heat for longer periods and 5) all this results in a slower lap time.

A and C exemplify the above, especially the doubletake non maximal inital application followed by the delayed second application. B shows a far too early application that is also a half hearted effort, whilst D even shows a flatter slope to the initial deceleration which I guess means that even the getting on the brake peddle and applying the pressure was slow and gradual as well as prolonged, rather than late and abrupt. This data can be quite instructive! I'm sure there is much more to learn from it. Getting onto the brake late, with immediate max foot pressure and minimizing the "area under the curve" looks like the goods.

I'd be very appreciative of any further instructioin or interpretation of what the data might be saying.

My next track day is on the 20th - I'll have to do better and put this theory into practice.

Grant, thanks for the information. Great to hear you are going so fast you need those big stoppers. Yours is a "track weapon" afterall. When I need those Cup Brakes, at least you and "Full Boost" Simon will have done all the homework for me. Here is a link to the Porsche Club Queensland evnets calendar. It would be great to see you up here of a track day. You will be able to teach you tropical cousins a lesson or too!
http://www.porsche-qld.org.au/Motors...S/Default.aspx

Cheers.

Malcolm

mattipuh

analyzing driving with such data is surely helpful - leaves less room for speculation, which is great after all. you really see where things could be done better. such would be great tool in getting those last few seconds off the lap time. Corner D seems nice, although true, the brake application could have been faster. then again, Being such a fast corner, jumping on brakes 100% and applying gas again is not the easiest thing to do.

for me, braking is really the difficult part (among downshifting), when talking about driving corners. In Finland our club events have sometimes correct braking points marked with cones, which helps you to get the feeling when would be the best time to apply brakes. This leads to learning the track inch per inch - where to start braking, where to apex, common stuff...

[off topic]DM993tt - which software you use in combining data + video? looks kind of simple and cool [/offtopic]

malcolmd

The Racelogic Performance Box provides the datalog via a CSV file output. This is then uploaded into RaceChrono2AVI (shareware) to provide the data overlay file. The track video was recorded in HD (quality reduced for YouTube) simply using a Logitec QuickCam Pro 9000 via my laptop. The two video files are then married using commercial software (I use AVS Video Editor 4 cira $50 - but there would be any number of cheap products to do this). The only real hard part is triming the two video files so that they both start at exactly the same time i.e the are synchronized. A few tries and it becomes easy. I simply look for the first frame of the track video that shows forward movement, and the first frame of the data overlay that shows the digital speedo showing movement to 1-2 KPH as the front trim points. It is easier therefore if both the start and end are defined by the car's moving from zero and back to zero speed. So the Logitec Camera is about $100, the laptop you already have, the overlay software is free and you might just have to buy the video editor as shareware examples often don't have the overlay option. Really inexpensive, easy to do, and lots of fun. It takes the computer about twice as long to created the merged file than it takes to do the preparation yourself. Give it a go!

DM993tt

[off topic]DM993tt - which software you use in combining data + video? looks kind of simple and cool [/offtopic][/QUOTE]


http://www.gboxtrack.com/index.htm
It was the cheapest thing I could find. Need to figure out how to get it to run in HD format.

Full Boost

Hi Malcolm,

Just to add fuel to the fire - regardless of your braking ability (personal) these are HEAVY (esp in stock form) cars.

QIR is a FAST track - and with your massive horsepower increase - you will be travelling when you need to brake...

To echo others sentiments - you need PROPER pads and fluid.... Ohh and brakes too
Big reds are old technology and as GF pointed out - Once you really start using the brakes - the wear will become a factor as well as the ability to really stop the car. The ambients are much higher in AU (especially rural QLD) for longer - and I did find the limits of the big reds - and i have a stock car - with the HP you are running and the weight - you will run out of stopping power soon....

Yes i have done and paid for the R&D for a bolt on solution...

GF - Long time - Whats the go with your brake upgrade?

Simon.