Brinkley

After some adjusting on the new Motons I was able to match my previous lap record and then beat it by 1 second (2:22.6), even with a huge oversteer in 15a (the second lap shown).

As ya'll get ready for the 48hrs enjoy another HD vimeo clip...

http://vimeo.com/19196000

Mark Dreyer

Very nice. I see your car out at Sebring frequently but have never met you. I'll make an effort this coming week at Winterfest. So what have you done to your car other than the Motons and big wing to get it so fast?

Brinkley

This week at Winterfest?? Do you mean the 48hrs? Unfortunately I will not be at the PCA 48hrs...

I usually run PBOC. Regarding changes, car is gutted and rebuilt as a dedicated race car. Moton's, Spring rate change, Motec ECU/Dash, a mix of fiber glass and carbon fiber parts, Hoosier Slicks.

Oh...and we replaced the 3.2L with a 3.6L 996 motor. As they all have said, the time really comes from staying off the brakes and staying on the throttle longer.

Mark Dreyer

Yes I meant 48 hours. Sounds like you have a good combination of well sorted car and driving skill! I enjoyed watching a couple Boxsters here at Daytona today racing in the Continental Tire Challenge Race. There were also a couple Caymans.

Brinkley

Mark,

I've seen your laps posted during your coaching experiences and from a few week/months ago to the lap you posted today I think you line has really improved (other than T3, which you stated) and T16 which I think you are early on. That causes you to lift mid corner which kills your back straight speed. If you keep working on consistency with those lines your Boxster will continue to gain time.

Before I put in the 3.6L, I was running PSS9's, stock ecu, and stock spring rates on Hoosier R6's and ran in the 2:26-2:28 range consistently.

You stated the car in today's video is on street tires so I understand why your braking so early but I would recommend pushing yourself to get your street tires to start singing in the corners. Work on T3-T5, T7, T10, and tower specifically. You want cornering speeds that cause the street tires to squeal which would indicate their starting to slide laterally. That means your nearing the edge of adhesion. If you normally run R6's those too should be pushed to squealing.

On my Vimeo channel there is a video with the camera mounted on the side of the car, right behind the LF tire and you can see and hear the R6 squealing around most corners.

VERBOTN

Very nice B. I want HP sooooooo bad. BTW got your email and will view this weekend. Catching up from travel. Thanks

mdrums

Awesome Chad!

PedroNole

Chad, Congrats on your new personal best!

A few thoughts/observations (some of these I know are obvious and that you know). We know each other so obviously I'm not coming down on you, just giving you some friendly feedback since you posted the video. I realize you didn't ask for feedback but I just can't help myself. I'm a giver...

1) With all of the work you've done to the car, I'm surprised you haven't re-geared the tranny yet. You will easily pick up a second or two from closer ratio gears. On your first lap, you didn't even get to 5th gear at the end of the back straight... You should be close to max revs in 6th there. THIS SHOULD BE YOUR NEXT PROJECT!

I'm not sure if you've seen a dyno curve on your engine but due to your gearing, you're winding out the top end of the gears so that the drop isn't so great but I would be willing to bet you that the stock 996 engine is pretty flat at the top in the last 800rpms. So, you're holding it in a portion of the curve where you're really not making any more power to compensate for your gearing and then when you do shift, the gear differential is still too great to make a lot of initial power in the next gear. You're getting double whammy'd...

2) Due to your "long" tranny, You need to grab for another gear more in certain turns. You need to make sure you're in the power curve as much as possible. Like turn one, you could grab a lower gear. You're so low at mid-corner that you really are out of the power/torque curve there initially for the run down to #3. Same thing at 10. I would really try to get down to second there and get a better launch off of that corner. Same thing at the Tower Turn. Same thing at 15 and 16...especially 16! I GUARANTEE you will pick a lot of time if you only grab for an extra gear in #1 and #16 alone...

3) In the safety-pin in both laps it seems like you had a lift after you initially got back on the throttle. You'd be amazed how much that little lift will cost you in the run down to #10....

4) Personally, I hug the right hand second apex when leaving the safety pin. You're about 1.5 car lengths away from it and it causes you to be a little too wide of the left hand apex heading into #10 too.

5) I think you can be tighter in #10 and, like I said, grab another gear...

6) You need to work on #15 and DEFINITELY grab another gear there.

7) I'm definitely a "inside" guy at 17. However, I think you're a bit too far in (mid-corner) and it's causing you to hit the really bumpy section and it causes you to delay getting on the throttle much too long. LOT of time there.

Again, just my opinion which I realize you didn't request....

Brinkley

Peter,

Thanks for the welcomed feed back. I don't want to rush your assessment and am about to get on a plane. I'll be gone till Thursday and will study when I return.

Thank you and I welcome any other input.

Veloce Raptor

Chad, very nice video, and I echo Peter's congrats! I'd like to add to what Peter says, after I strongly recommend you invest in some SUNGLASSES!!!!

As he says, the 996 street motor generally makes more noise than power at the very top end of the range. I have spent some seat time in Spec 996 cars, and I find that my times are better if I generally upshift slightly short of redline. Plus, this is a bit easier on the equipment. Now, whether this predicates regearing your car or not is up to you...but your gear selection could be improved in several places, with the existing gears, to go faster IMO.

In 1, I am a big fan of bending the car in slightly sooner, and with slightly less steering angle, and hugginthe wall tight for a bit longer. What you do is almost there, and I am just offering my opinion, but I believe you could carry more throttle all the way thruu there (especially with that wing).

In 7, I agree with Peter, and think perhaps one way to solve this lift is more aggressive trail braking. I can see from your feet that you already are...but with that monster wing, you can really trail brake the hell out of that car!

Same in 10. You are apexing way too early there, and then fighting to keep the car away from the trackout curbs on the left, delayying throttle for a while. IMO if you trailbraked more aggressively there, the car will point bettter at apex, and thus you can straighten the wheel sooner, away from tnje trackoout curb, and hammer it.

In 15....you need to downshift IMO.

In 17, to add to Peter's comments, if you were maybe a foot to the left of where you were in the video, IMO you'd miss the worst of the buump and carry a lot more speed there.

As you know, at your level, these little nuances take on greater & greater meaning. JMHO!









Professional Racing and Driving Coach

FredC

Stout driving. Thanks for sharing. Could you benefit from moving the steering wheel closer to your chest with a hub extender though?

Brinkley

Peter and VR,

I know its been a week since you posted some suggestion regarding a Sebring lap and I want to thank you both for your time reviewing and commenting.

Regarding the idea of re-gearing the tranny, its a stock Boxster S 6 speed and there is currently only one company supplying an aftermarket gear set. I have been told that the ratio's they picked are not that different from stock and therefore do not give you much of a change for the cost. There is another company that sells an aftermarket ring and pinion. This is also not a good option due to a wear issues.

So, here is where I stand on T10 and Tower with the downshifts. Data shows I'm at 53mph and 59mph respectively. If I downshift to 2nd, my problem with the stock gears is 2nd red lines at 62mph. So by going down to 2nd I barely get on the gas and I have to shift to second. And while I'm in 2nd the motor is turning near 6900-7200 rpm's so I'm out of the powerband there as well. My goal is to carry more speed in the corners so 3rd will be a better gear.

Regarding my lack of a downshift at 15a, that's something I've been working on. I compared downshift to 3rd vs. staying in 4th and downshifting at 16 and found that it was quicker. The reason, when I downshift to 3rd I tend to over-slow the car to ensure I'm not at the top of the rev band. By over-slowing the car it slows the lap time down.

Regarding the first lap on the back stretch when I didn't shift from 4th to 5th, that was my fault. I was thinking about something else...

You both stated there is a lift in the hairpin after I get back to throttle. The data does not support this nor do I believe I lift. In actuality, I believe what is heard on the video is an audio variance that is causing it to sound like a lift when there is not.

I'll work on some of the trail braking that you suggested however just to see if i can carry more speed through there.

mark kibort

Saving the engine is one thing, but even though that "noise" may be low torque and acceleration, its going to be a lot more than the next gear shift, where your torque is actually a lot lower to the wheels, due to having less power at the post shift RPM. certainly there are cases to short shift, but mainly those are when the post shift HP is greater (usually near redline) or when the actual shifting time (where you have a fraction of time of neg acceleration) is offset by the greater acceleration in the next gear power. (or when grip doesnt allow, or when its not a good place on the track to upset the car with a shift)
you may have seen "better " lap times by short shifting, but something else happened in those laps, besides getting greater accelerative forces by doing so.
a 996 motor is pretty high strung and always pays accelerative dividends by shifting as high of an rpm as possible.





are their close ratio gear boxes available for the 996? are you talking cup car transmission ratios?

I dont understand the "double wammy" of your point, "1". "not making any more power to compensate for your gearing". ?? the 996 engines make power up top. if you are making more power in that gear up top, then a shift usually will be a drop in power, which provides less acceleration.
So, i think you must be refering to a close ratio gear box, not just gearing down.
I agree that he could have gains following your shift point suggestions in point #2 I just want to make sure you are not calling his gears long, when you really mean "Tall". if the gear spacing is the same with any two gear boxes, there will be trade offs in power optimization around any given track. whether it is better for one track vs another depends on total power, car, and driver.

Great lap by they way in that little hybrid porsche! 2:22 is fast!

Below are two graphs of a GT3 and a 997 3.6 motor. you find your gear ratios and see what short shifting does to available HP post shift.

For example. if you short shift , even just 200rpm with a shift that ends up at 75% of your pre shift rpm, you lose near 70HP!! depending how long you accelerate for those 200rpm, you are at a 70hp loss for that period of time. this is substantial! (eg: 8200rpm shift from 360rwhp, to 6000 or 6200 post shift at 290 /300hp)

Veloce Raptor

Sorry, Mark, but you're wrong. Get some seat time in a 996 non-GT3 and then rejoin this conversation.









Professional Racing and Driving Coach

shustermeister