Spec Boxster Build

[stephen wilson]

You can shift mid-corner, you just have to be aware of the results, which will vary depending on the car and corner (speed). At Summit Point in my Formula Ford I pull 2nd in the middle of 5A /5B, which actually helps rotate the car for the exit.

[thstone]

Originally Posted by steved0x

I've always wondered, how do you shift when you are in one of those long banked sweepers? It seems like lifting off the throttle to shift would upset the car. Is it because there is so much grip due to the banking that the car is nowhere near the limit and so a brief lift to shift is ok?

Steve

On this track, there is a very long straight before the fairly steep banking, so a Spec Boxster will run flat out the entire way. Faster cars will typically brake and downshift prior to entering the banking and then carry a near constant speed through the banking - so no need for an upshift.

In the upcoming Sunday race video, I had to lift mid-corner and the change in balance pushed the car up the track towards the wall and I had an "oh crap!!!" kind of moment. I got back onto the throttle and kept everything under control.

I wouldn't want to try shifting mid-corner on the banking unless I was an experienced NASCAR driver.

[steved0x]

Looking forward to the video. If I ever get to Daytona I will probably short shift up to 5th or 6th before getting on the banking... If I ever get to go

[thstone]

While editing the Race #2 video this evening, I remembered a wicked slide that happened as I was coming off the NASCAR banking into Turn 3. For a moment, the inside wall was straight ahead. Like this...

Video is rendering now, should be posted tomorrow!

[Topless]

Originally Posted by thstone

While editing the Race #2 video this evening, I remembered a wicked slide that happened as I was coming off the NASCAR banking into Turn 3. For a moment, the inside wall was straight ahead. Like this...

Video is rendering now, should be posted tomorrow!

Haha, you got this! Just about to lap Vince in his 951.

[thstone]

Race #2 video!

Sorry for the long duration (11 mins), but there was a lot going on for those 11 mins! Watch to the end to see the slide shown in the still photo above...

Also of note: the temps for the weekend were in the mid-90's and my car did double duty with me and my son driving (often for back-to-back sessions) and I never saw any temps over the "0" in 180. This is with no center radiator and only one radiator fan.

One more note: My car is still 50lbs overweight. I am convinced that losing ground off of the corners is sometimes due to the additional weight (other times it is definitely that the other car simply exists faster).

Furthermore, for this weekend, the passenger race seat and harnesses (25lbs) were in the car for my son's time trial instructor along with my cool suit system (10 lbs) and I ran the fuel pretty high because we wouldn't have time to go and get gas between my race and my son's time trial session. Add it all together and I was around 130 lbs over the minimum weight. That's a reasonably large weight penalty.

Of course, I could easily lose 25lbs myself but ... but.... but...

Ok, enough talk. Here's the video. You know the drill (HD with sound)...

[thstone]

How about some MORE video?

I came across a video from Dwain Dement, POC Chief Driving Instructor and quite an accomplished racer where he is chasing me down for the pass in Race #2.

There is a really great shot of us driving side by side as he passes me and then I power slide through Turn 5 trying (in vain) to keep up with him.

Enjoy!

[RedTele58]

Thanks for the videos Tom! There is nothing more fun and challenging than being on a track full of Porsches.

[steved0x]

Originally Posted by thstone

.

There is a really great shot of us driving side by side as he passes me and then I power slide through Turn 5 trying (in vain) to keep up with him.

Cool external view of that pass and the slide. Your red wheels looked really good in the video too.

Steve

[thstone]

Here are a few pic's from two weeks ago at AutoClub Speedway...

[Porsche9]

Thstone, how did you do?

[thstone]

Originally Posted by Porsche9

Thstone, how did you do?

Race #1: Started 6th of 13. Running 5th with two laps to go when shift cable broke. Finished 13th.
Race #2: Started 7th of 11. Fell back to 9th, moved up and finished 5th.

Hoping for better results in November!

[Porsche9]

Originally Posted by thstone

Race #1: Started 6th of 13. Running 5th with two laps to go when shift cable broke. Finished 13th.
Race #2: Started 7th of 11. Fell back to 9th, moved up and finished 5th.

Hoping for better results in November!

Looks like a lot of fun and sounds very competitive. Thanks.

[JRide]

Awesome videos. Thanks for sharing! I haven't raced (motorcycles) in 5 years and you're making me want to get back out there.

That was a great save. The rear came around QUICK!

Hoping to do my first car track day next season.

[thstone]

Originally Posted by JRide

Awesome videos. Thanks for sharing! I haven't raced (motorcycles) in 5 years and you're making me want to get back out there.

That was a great save. The rear came around QUICK!

Hoping to do my first car track day next season.

Yeah, its a lot of fun out there! And yes, when a Boxster starts to come around, it rotates pretty fast and will take quick hands to catch it.

Hope that you get to experience that track day next spring, it will be incredible fun.

[thstone]

Time for new brakes!

The pads/rotors are usually done twice a year (spring and fall) and I flush the fluid once per year (fall).

Having a lift sure makes this job easy on the back!



At the end of the day at AutoClub Speedway, the pads were starting to sound bad and by the time I drove the car home, it was clear they were all the way gone. Initial inspection confirmed it...



Pad was down the metal backing plates on both fronts...



Notice the pad thickness difference from before to after!! New EBC YellowStuff racing pads.



I also removed the brake splash shields. Driver side was bent and was continually making a scraping noise. The brakes should also cool a little better with them removed. I didn't remove the hubs, simply cut the shield using a pair of tin snips and bent it around the hub for removal. Before and after photos...




Last, here is the new (left) and old (right) brake fluid after a year of racing. Based on this, I should probably consider flushing the brake fluid twice a year - but at least it makes it easy to visually tell when all of the old fluid is out!

[thstone]

OK, let's talk horsepower.

At the AutoClub Speedway race, the POC had a dyno to measure power output at the rear wheels (there is currently no maximum power spec). The top 3 qualifiers and top 3 race finishers were required to have their cars tested. I had mine tested of my own desire.

Here are three data points;

My Car: 196hp
Car 2: 187hp
Car 3: 203hp

From my perspective, its good news that my $1,800 salvage yard, never been opened, previous tiptronic, engine with 90,000 prior miles still managed 196hp at the rear wheels!

Of course, you might be wondering: with a rating of 200hp at the crank, how can I get 194hp at the rear wheels from a stock engine?

200hp at the crank
- 20hp 10% driveline loss
+ 7hp TopSpeed cat back exhaust (verified on dyno: Spec Boxster Build)
+ 5hp Removal of cat's (verified on dyno)
+ 5hp Under drive pulley (per other testing)
________
196 hp net at the rear wheels

Of course, there are some uncertainties in the above calculations:

• Rated horsepower (could be higher or lower than 200)
• Driveline loss (could be higher or lower than 10%)
• Differences in dyno testing (lots of variables)

Car 2's engine was professionally rebuilt last season and has only been used for racing and driving to/from races. Interesting that it has slightly less power than my never-rebuilt engine. This engine reportedly was dyno'd at 192hp when rebuilt.

Car 3 is making quite a bit more power than my car. Even if I add a few more HP for a fully open exhaust (which my car does not have), there still isn't an obvious path to get my engine to 203hp.

In fairness to Car 3, a combination of the uncertainties listed above might explain the difference. Impossible to know one way or another, but interesting to consider the possibilities.

Now, for the drama... (Oh! The Drama!)

Because of this situation, Car 3 was protested by Car 2. This meant that Car 3 had to post a $3,500 check to pay to have the engine of Car 3 inspected. Car 2 refused the inspection, and thus, was disqualified for all three races for the weekend (and the $3,500 was returned to Car 2).

I don't want to indict Car 3 for refusing the inspection but it does raise eyebrows. I'd let anyone inspect anything on my car at any time (including tearing down the engine).

I don't know what, if anything, further will come of this situation for Car 3, but I found the horsepower numbers, situation, protest, and refusal to be inspected to be interesting and worth sharing.

[thstone]

Dyno results;

[Eric523]

I was the car that came second in qualifying and I wasn't put on the dyno. It was supposed to be random selection. I had rented a car for the race and I think the rental has about 191-193 in it. Give the competitive field of drivers and the full second that the lead car pulled on us, I was interested in the dyno results.

After seeing the results. I was also the one that protested car #1, simply because no legal spec car has ever posted over 200. I also had to write a check for $3500...

At first, car #1 was going to comply with the inspection and insisted the car was stock and I'd lose my $$. The next day... decided to go home instead.

Last weekend a lil birdie told me car #1 has since purchased a new engine. Decided not to go through with the inspection so we didn't find out what was making the additional power on the dyno.

Anyway...I don't have a lot of patience for that kind of stuff. I've been DQ'd before for removing my immobilizer but that was another issue and not performance enhancing at all (never over 186 on the dyno)

[thstone]

Originally Posted by Eric523

I was the car that came second in qualifying and I wasn't put on the dyno. It was supposed to be random selection. I had rented a car for the race and I think the rental has about 191-193 in it. Give the competitive field of drivers and the full second that the lead car pulled on us, I was interested in the dyno results.

After seeing the results. I was also the one that protested car #1, simply because no legal spec car has ever posted over 200. I also had to write a check for $3500...

At first, car #1 was going to comply with the inspection and insisted the car was stock and I'd lose my $$. The next day... decided to go home instead.

Last weekend a lil birdie told me car #1 has since purchased a new engine. Decided not to go through with the inspection so we didn't find out what was making the additional power on the dyno.

Anyway...I don't have a lot of patience for that kind of stuff. I've been DQ'd before for removing my immobilizer but that was another issue and not performance enhancing at all (never over 186 on the dyno)

Eric, thanks for the clarification on several points. Also to be consistent - the car that you protested was what I called Car 3. See you at Buttonwillow.