Taking autocross srsly - SCCA CS / PCA P03 986 Porsche Boxster S build #Nats2020

I debated long and hard here and on racing fb groups about whether or not to make the Cobra autocross well or get a different car, and if so which car and which class. After much ruminating including looking at the Cobalt SS/SC for GS, I settled on the 986 Boxster S as a dark horse for CS. (GRM thread) A search was put forth and I have finally purchased the victim, er "candidate" was located. 

It's a 2000 Porsche Boxster S, Finland build, with 2 options: cruise control and the wind deflector. The PO added the correct stand-alone 18" wheels and it's otherwise a stone stock 138K mile example with complete service records including IMS, new clutch, and a 33K mile used transaxle all done at Porsche dealers. I paid less than the PCCB brake option for the 718 Boxster for the whole car.

Cue the intro video:

I'm going document everything about this build here and on YouTube. It's going to be a dedicated autocross car for C Street in SCCA and may dabble in P03 for PCA as well since there's good overlap. I will be attending the SCCA National Tour and ProSolo in Packwood this season and the end goal is my first trip to Nationals in Lincoln in 2020.

Awesome, I will be following along

Congratulations on your purchase, looks like a good score. I'm looking forward to seeing it evolve. Can't wait to see the next update.

I'm planning to follow the same recommendation for picking a class, then the car. I'm staying in E Street, selling my modified NB2S, shopping for a stock NB1.

I would love to follow your lead, and look for a Boxter S, but I need to stay as cheap as possible. We all know what the answer to that is...

Awesome, interested to see how things progress. Have you run many national events in the past? After running a bit with "3rd party" autocross clubs, I want to step up to SCCA local events for the competition, and hopefully national tour events, and maybe even a Nats one day.

ApexEight said:

Awesome, interested to see how things progress. Have you run many national events in the past? After running a bit with "3rd party" autocross clubs, I want to step up to SCCA local events for the competition, and hopefully national tour events, and maybe even a Nats one day.

I ran my first National ProSolo in 2018. I've been autocrossing with my local SCCA and PCA since 2008. The plan is to develop the car this season and do the Packwood National ProSolo and National Tour this season and then in 2020 do them again along with Crow's Landing in California and the actual Nationals in Lincoln in September.

Congratulations on your acquisition. I will be following along to see what upgrades you make. I bought a base model 99' Boxster a couple months ago and will be getting it ready for autocross as well. Do you have an idea of the things you want to upgrade?

Nice buy!  And good to see another Boxster on the forum.  I raced mine in SCCA B-Stock for years.  I’m looking forward to seeing your build.  

tedroach said:

Congratulations on your acquisition. I will be following along to see what upgrades you make. I bought a base model 99' Boxster a couple months ago and will be getting it ready for autocross as well. Do you have an idea of the things you want to upgrade?

Thanks! Yes, I know everything that can be done and have decided on most of it already. In fact, the car has been in a shop since I bought it having the suspension redone and it's just about completed. That's likely the next episode.

Time for an update! The Boxster has been at PRE Racing in Portland getting new Koni Sports and the rest suspension refreshed. Take a shop tour with us in Episode 2 of the build series.

In reply to Javelin :

Totally in for the sway bar testing.  Let’s see how they do.  With more weight on the rear I’m betting on the stiffer rear bar.

That's great! The deep class of great drivers in In S1 in our local SCCA will be the perfect test. Can't wait to see the results!

Is the later S able to get a reasonable amount of front camber? My 2.5L base car is limited to like .5* which seems like it would be a huge negative to the chassis. Not that the ND has a ton of camber, but 1.5* or whatever they can manage plus DW suspension versus .5* and struts seems like a big difference. Mine certainly drives like the front camber is a limiting factor, but then again I'm down 50+ hp and running on old tires so it's not exactly a great comparison. It'd be great to learn that new tires and maybe a swaybar would improve that situation though so I'm interested to see what you come up with.

AnthonyGS said:

In reply to Javelin :

Totally in for the sway bar testing.  Let’s see how they do.  With more weight on the rear I’m betting on the stiffer rear bar.

 

We're thinking that with all of the weight being on the rear of the car that the front bar will be the one to have and then we can dial in more rotation with rear toe changes.

freestyle said:

That's great! The deep class of great drivers in In S1 in our local SCCA will be the perfect test. Can't wait to see the results!

You ain't kidding! ORSCCA has a deep pool of great drivers and lots and lots of Nats jackets. I'm going to try and wrangle a few of them to drive the Boxster to get some feedback and see how it's stacking up without having my driving be a factor.

In reply to dps214 :

PRE is aligning the car today, so hopefully I'll have some numbers by the end of the day. There's many tricks involved in getting a great alignment and most of them take a ton of time. We did have to split the weight of me and my co-driver for the ballast in the driver's seat. We're hopeful of about -1.2*.

Alright, here we go! The car is finally home from purchase via it's stay at PRE and I have the next episode up.

Alignment did not go exactly the way I wanted. With fresh suspension in place -0.3* of camber was all we could squeeze. We tried every trick in the book, but that's all she wrote for now. We will run a few thousand street miles and maybe 3 events before checking again in case the suspension settles in. (Note - ballast was at 155 pounds in the driver's seat to split the difference between me and my codriver.) Everything else dialed in nicely. 7.9* of caster, -1/16" toe per side in the front. In the rear we got-2.15* of camber and set toe at exactly 0" for now. I am going to run the front sway bar (thinking of picking up a 996.1 GT3 bar) and 235's on the front (for minimal sidewall flex) and if it starts to plow dial the rotation back in with rear toe changes. (Remember, it's a dedicated autocross car!)

The other really important bit: weight. The car in complete street trim including service records and owner's manual in the car, the radar detector system, the spare/jack/tools, and a box of spares in the trunk scaled at 2953 pounds, or only 98 pounds higher than the lightest factory curb weight. Considering we already have the 18" wheel setup, that's great! 811 pounds on each rear wheel, LF was 695 and RF was 636 for a F/R bias of 54.93% to the rear. (Top up, 1/2 tank of fuel.)

Now that it's home I'll pull all of the extra junk out of the car (and weigh it), clean it up and check for phantom weight (dirt and rocks hiding!), and replace the fluids. On the tire front, thinking of a 235/285 staggered setup on the Bridgestone RE71R's. The goal is the first Bridge City Autosports event of the season, 2/24/19 at Portland International Raceway. Come run with us!

Why did you decide on the Koni Sports instead of Bilsteins?

I’m really following along closely.  I am focusing on my cam/challenge car right now, but next year I will be doing my boxster based a lot on what I learn from this project.  

tedroach said:

Why did you decide on the Koni Sports instead of Bilsteins?

Adjustability. The Bilstein B4, B6, and B8 for the Boxster are non-adjustable and the B10 and B12 are coilovers, which are not legal in the Street Category. I am forced to use stock springs and the Koni Sports gave the best option at the limitations of the rules.

Part numbers 8741-1573SPORT for the front and 8740-1574SPORT for the rear. Tire Rack has them for $263 and $191 respectively. 

AnthonyGS said:

I’m really following along closely.  I am focusing on my cam/challenge car right now, but next year I will be doing my boxster based a lot on what I learn from this project.  

Thank you, I really appreciate the feedback! 

Javelin said:

tedroach said:

Why did you decide on the Koni Sports instead of Bilsteins?

Adjustability. The Bilstein B4, B6, and B8 for the Boxster are non-adjustable and the B10 and B12 are coilovers, which are not legal in the Street Category. I am forced to use stock springs and the Koni Sports gave the best option at the limitations of the rules.

Part numbers 8741-1573SPORT for the front and 8740-1574SPORT for the rear. Tire Rack has them for $263 and $191 respectively. 

Awesome. Good to know. I will be changing the shocks on my Boxster as well and the Bilsteins are expensive. I will check them out.

Watched your latest vid over my lunch break. It's awesome that you are making this series; I really don't of anything else like it on YouTube and it's what I've been looking for! This is all making a Boxster S an extremely intriguing, and more importantly, realistic, weekend/fun car. Excited to see what comes of your test and tune. I wish we had something like that here in Atlanta, but our SCCA season is starting in mid-February and I don't know of any other organization running events before that. Keep up the good work!

In reply to ApexEight :

Wow, thank you so much! I also have not found any other serious autocross build as a series on YouTube, so I hope I can foster more of them to appear because I find the rules and builds fascinating. Share it with your local SCCA.

Javelin said:

On the tire front, thinking of a 235/285 staggered setup on the Bridgestone RE71R's.

Back in the RE01R days, a friend found their 986S was quickest with 245 front / 255 rear.

I'll have to watch for you at autocross this season. I haven't run with ORSCCA yet but I have been thinking about it to try some new venues. I will definitely be at the Packwood ProSolo this year. I feel like the Boxster should be a great platform, but there are so few that come out to NWR events.

I'm sure you know that NWRSCCA runs two regional ProSolo events each season that are really fun and cost as much as a typical regional autocross. Very low stress, just fun.