Boxster 986 Autocross/Track Setup
 

I just bought a 1998 Boxster Base model to be used as an autocross/track toy. I’m trying to get the setup squared away for the upcoming racing season and was wanting opinions or suggestions on what I have planned. So here it is:

Car
1998 Boxster Base Model (2.5L)
Manual
Right now, everything is stock with Factory Aero Package

SCCA Autocross STR Class Setup/Additions:
Stock 17"x 7" fronts and 17"x 8.5" rear wheels
Bridgestone RE71Rs (225/45-17 front & 255/40-17 rear)
Wheel Spacers as Needed (up to 7mm allowed by SCCA STR)
Tarett Front Camber Plates
Tarett Front GT adjustable sway bar and drop links
Carbotech Xp8 Brake Pads
Race Exhaust with CATs
Deep Sump Oil Pan Kit
Underdrive Pulley Kit
Brey Krauss Roll Bar Extension

Track Setup (same as above with following additions/changes):
OZ 18"x8.5" fronts and 18"x10" rear wheels
Toyo R888Rs (235/45-18 front & 265/35-18 Rear)
For Wet Track: Back to stock wheels and RE71Rs

How does this look to everyone?

Should I go with front LCA instead of plates (can’t do both LCA and camber plates in SCCA STR)? With the limited camber provided by plates will R-compound tires cord prematurely on outside at the track?

Should I go with Nitto NT01s (my favorite track tire) instead of the Toyos? The NT01 rear in 265 width (265/40-18) is an inch taller than stock.

Adjustable GT3 Arms cost more than camber plates but you get what you pay for with a wider trac and better tuneability. Worth it to me.

If you don't plan to change the struts, the stock sways are ok. Changing to a M030 on the rear allows the car to rotate more easily without generating wheelspin.

RE-71R is the ideal AX tire for setting quick single laps.

I would probably stick with 17" stock wheels for track days and run NT01 in 225/255. I ran 20 sets of these on my 986 and they are just about the ideal tire for affordable continuous lapping. They hold up to heat much better than 888s.

Tires in the 17" sizes are much less expensive than 18" sizes, so I'd just stick with the 17".

If any thing, the 18's could be your wet setup, as they'd soften the delivery a bit. But I'd personally stick to the 17's for all setups.

I agree too that the LCA's give you the advantage of wider track, compared to the plates.

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Thank you for all of your input.

I already have the stock 17” wheels for the RE71Rs for autocross. I also already own the 18” OZ wheels that I had from when I tracked my 997. Based on my research, another set of 17” wheels will cost me between $500 and $1000. The difference in cost between the 17” NT01s and the wider 18” R888Rs is about $250.

Does that change any of the recommendations? Will the limited number of runs that I get out of the R888Rs versus the NT01s quickly eat up the cost savings realized by using the 18” wheels versus buying new 17” wheels?

I’m a big fan of the NT01s, so I won’t need a whole lot of convincing. And, if you tell me the 17” NT01 setup is faster I have some 18” OZs for sale.

Definitely run the 17”s, not the 18”s. it didn’t always used to be the case but now track tires and autocross tires are very different. Autocross tires will not last long at all on the track and most will over heat after a single lap (there are some exceptions like the Rival S) and track tires will not be sticky enough for an autocross if you’re trying to be competitive. It’s all what you want to do.

I didn’t think you could add lower control arms in SCCA? If you can do that over a front sway bar, Boxsters understeer and a front bar doesn’t help. Finally can you go wider on that front tire (I believe you can within scca rules). I’d go as wide as you can for track or autocross. Good luck!

my 2 cents:

An absolute must is adjustable front lower control arms. I'd suggest tarret because they have a beefier ball joint or maybe elephant racing.

I'd stay away from the underdrive pulley because it may or will limit the ability to change the IMS down the road and I'm not sure the hassle is worth it.

Remove the side intake tube. It doesn't make a big difference but you'll get a slightly better airflow & sound.

Lastly, try to reduce the car's weight as much as possible. Not sure what the aero package entails but its likely additional weight that is not needed.

Its a great autocross car in stock-ish form so enjoy.

Explain? Ya lost me.

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I'm also lost.

Be aware that what you choose to do depends on what organization(s) you decide to autocross with. Also understand that the class rules may differ from region to region with some national organizations.

For example, if you choose to autocross with PCA you need to check the class rules at the regional, zone and national level. In my region (NER Northeast), you have street classes that require that you don't modify anything that may affect performance. This includes adjustable coilovers, camber plates, any engine modification between the throttle body and exhaust manifold, both included, etc. etc. Then there is the modified class where you can make those change. For these two you cannot use tires with under 200 tread wear, which the RE71-R complies with. And finally there is the class where you drive on R rated tires.

Understand that the non-street classes is where the big boys drive. You will be crushed!

So, here's my advice: Read the rules, drive in street class until you are one of the top drivers. It is less expensive and more fun. Once you have the experience and the $, go for it in the other classes.

Enjoy/Anker

Oh, I forgot.

Change your alignment.

Maximize the front camber with the stock camber slots. Set your front end toe-in to 0 degrees. Set a small amount of toe-in on the rears and set the camber to as much as you can with the selected toe-in (they interact). Use RE71-Rs on 17" rims. You will run 225 wide tires in front instead of the standard 205s. That's all Bridgestone supplies. That's what you want anyway because it increases front end grip.

Based on the responses below, I plan to change alignment as recommended and use LCAs in the front to get the camber needed so that i don't wear the outside of the track tires so fast. I'm also now convinced that i need to sell my 18" OZ wheel set and get another set of 17" wheels as my dedicated track wheel set [with NT01s - 225 (or 235?) in front and 255 in rear]. The original stock wheels will have the RE71R autocross/rain tires mounted (225 in front and 255 in rear). I also plan to install roll bar extension, race seats, harnesses, underdrive pulley and deep sump pan kit - all recommendations for track use.

Some of the track mods listed above are not allowed in SCCA C Street class but are allowed in the Street Touring Roadster (STR) class - at least based on my interpretation/understanding of the rules. STR is the class i plan to run in autocross.

Another round of questions based on suggestions below:
1. Front or rear adjustable sway bar? Neither? Both?
2. Will 235 fit on front with LCAs and stock struts?

To fit the 4" pulley you'll have to shave off part of the TDC (top dead centre) boss which is a hollow alloy protrusion cast into the crankcase. It is used to fit a TDC rod when locking the camshafts as part of the IMS replacement procedure.

That is my understanding.

aaah, yes, this is true. Thanks for helping me connect the dots, hehe.

However, at least in my case, enough remains of the 'boss to still use the pin. Regardless; there are other means of finding TDC, and locking the crank, if IMS replacement is desired. But a "fancy-pants" shop may not be willing to work outside-the-box like that. So consideration might be appropriate.

Still hoping to get an answer to the following questions:

1. Should i do a front or rear adjustable sway bar with stock shocks/struts? Or should i do both? Or should i do neither?
2. Will 235 fit on front or is 225 the max with LCAs and stock struts?

Do both. The staggered tire setup's will definitely tend towards understeer. The adj sways will help you balance the handling by dialing out some of that understeer.

235 should fit on the front with both the 7" and the 8.5" wheel.

The previous owner did really well with my car in autocross; but is autocross all i can do with my Boxster without adding the Brey Krauss Roll Bar Extension? Or do some tracks allow Boxster without it?

Any PCA Event should allow you to run as-is (pass the rest of the tech inspection, of course). The Boxster is on their list of approved convertibles.

In my experience, many other organizations have deferred to PCA for that determination and will also allow them to run as-is.

Where I think you're most-likely to run into a problem is at tracks which aren't frequented by PCA, and at tracks who are promoting their own track days independent of another organization. In those instances you're more likely to run into someone who is unfamiliar with (or simply doesn't care about) what other organizations allow, and they'll want to apply some variation of the "Broomstick Rule".

Tell us what your home track would be, and maybe there are people here with some experience who can help.
It's always best to ask your event organizer, and please post what you find.


Edit: for clarification, I'm talking about track days, HPDE's, time trials, etc. You will not be allowed wheel to wheel racing without a full roll cage.

hey, actually the event i found via PCA website was at Virginia Int'l Raceway but they require roll bar extensions on all cabriolets/boxsters, guess i'll autocross for now

hey thanks for the reply...the race i found is a PCA event at VIR (Virginia Int'l raceway) but registration says it requires rollbar extensions on all cabriolets/boxsters

Yeah i found a track event near me via PCA but its at Virginia Int'l Raceway which requires the Boxster to have the rollbar extension

It’s my understanding that VIR requires a rollbar extension on Boxsters. Can’t remember where I read that though (Hurricane Chapter newsletter? Here? VIR website?), but after reading it I went ahead and got a Brey Krause.

I ran 255/255 square for a year on stock struts and 8.5/17" wheels. They will fit. If you roll the fenders you can mount 285/285 square.

Tire Pressures (and brake pads)
 

I have my first autocross and track day of the season in a few weeks. I was wondering if someone could give me some tire pressure recommendations. This is the setup that I will be starting out with:

Car
1998 Boxster Base Model (2.5L)
Manual with Aero Package

SCCA Autocross STR Class Setup:
Stock 17"x 7" fronts and 17"x 8.5" rear wheels
Bridgestone RE71Rs (225/45-17 front & 255/40-17 rear)
Front LCA (this is my only suspension mod at this point)
Carbotech xp8 brake pads (or should I stick with stock for autocross?)

Track Setup (same as above with following additions/changes):
OZ 18"x8.5" fronts and 18"x10" rear wheels
Toyo R888Rs (235/45-18 front & 265/35-18 Rear)

Tire Pressures (and brake pads)
 

I have my first autocross and track day of the season in a few weeks. I was wondering if someone could give me some tire pressure recommendations. This is the setup that I will be starting out with:

Car
1998 Boxster Base Model (2.5L)
Manual with Aero Package

SCCA Autocross STR Class Setup:
Stock 17"x 7" fronts and 17"x 8.5" rear wheels
Bridgestone RE71Rs (225/45-17 front & 255/40-17 rear)
Front LCA (this is my only suspension mod at this point)
Carbotech xp8 brake pads (or should I stick with stock for autocross?)

Track Setup (same as above with following additions/changes):
OZ 18"x8.5" fronts and 18"x10" rear wheels
Toyo R888Rs (235/45-18 front & 265/35-18 Rear)

For the RE71-Rs the best tire pressure is just over 30 PSI front and back. Fine tune it by chalking your tires. Check the pressure after each run to compensate for heating.

I have not run Toyo R888Rs on track, but have tracked RE71-Rs and found that they overheated. Suggest you start with a fairly high pressure, like 34 PSI front and back and measure tire temperature with a tire pyrometer after the tires have warmed up. For the Toyos they publish a recommended temperature range. If the tire gets too hot raise the pressure, if too cool, lower it.

I've had both my first autocross and track day weekends in the Boxster. My setup is as mentioned below in previous post but i thought i would include the following:

SPC LCAs in front. Front camber is set at about -3 each side. Camber is set to max stock setting in rear. No adjustable anti-roll bars (yet). No toe links in rear (yet).

Here are my initial impressions:

Autocross
Positive: Balance was awesome!! I just kept ramping up the speed in the longer sweepers until I started to get a four wheel drift. They also had a skid pad element set up in the course and I didn't get as much understeer there as i was expecting. I'm sure that was the result of the increased camber in the front. Kept lowering the pressures in the RE71Rs until i was rolling over to the tips of the triangles on all four tires. Not surprisingly, when i got there i was getting my fastest times - that occurred right at about 30psi. That will be the pressures i am shooting for from now on. This car will be competitive at the local (and regional?) level in STR class.
Negative: Started to get a roaring noise in the turns (both directions) at the end of the first of the two-day weekend. Noise continued through second day. At first I suspected tire rub but quickly eliminated that. Suspected it was a wheel bearing but those checked out OK later by mechanic. Mechanic said he heard some noise in the gearbox/diff and changed the fluid (no debris). That certainly seemed to help with the noise (see below).

Track Day at Hallett the Next Weekend
Positive: Not much i can say here. The only positive was that the roaring noise did not reappear. It appears that the fluid change helped. However, I never really stressed the car like i did on the autocross day because of the conditions (rain).
Negative: The day was fun but it rained and the track was wet all day. I had no grip and had lost a lot of confidence in the car by the end of the day!! Tried both the new R888Rs and RE71Rs but neither was better than the other in the wet. The rear end was squirrely, especially if the rear became unweighted cresting a hill and going into a corner. Rear end also felt unstable under heavy braking just before turn in. It seemed like the car was going to come around on me under heavy braking.

Question: Did the rainy conditions expose an issue with the car? Could it be a bad rear toe setting? Could the roaring noise be a problem with the diff that is creating traction issues? I've done quite a few track days (dry and wet) in the past in my 997 and never had any issues like this.

Also, I find it a lot harder to heel-toe in this car. The bite in the brakes occurs very high in the brake pedal travel and I'm having difficulty rolling my foot far enough for the throttle blip. The throttle pedal is quite a ways below the brake pedal (even when really standing on it) and the result is unsteady brake pressure as i am trying to roll my foot way over. Are there adjustments that can be made?

VIR is the only HPDE Track that we have run into this difference of opinion/requirement with.

Once things are running again, check out PCAPotomac.org - likely your home region, or a neighbor. If you are in DC to Richmond area, you may consider Summit Point, WV.

The height of the brake pedal can be adjusted, but you may find on a dry day with more traction that the pedal will drop a bit due to heat.
If you run brake pads with more bite on the rear that will help stabilize it. More rear toe can help too.

You've got all this money in wheels and tires and are running on the track with blown out stock suspension? Don't exactly follow your thought process there. I'd find some decent coilovers.

Heel toe is super easy in these cars. Use your heel on the accelerator by rotating it outward. The pedal coming up from the floor instead of down from the top really makes heel toe easier by a large factor compared to other street cars

You just discovered the difference between 50/50 weight balance in the Boxster and 62/38 in the 997. The 997 carries a lot more weight over the (larger) rear wheels which help to keep it planted.

If the Boxster rear is too loose, you might want to adjust the sway bars to better balance the handling. But I would wait until you get a chance to try it on a dry track.

Tires also make a huge difference in the rain. I never thought of either of the tires you used as optimized for wet traction.

I had the same problem so I installed a set of Rennline pedal covers and accelerator pedal extension and height adjustor. This made it 10x easier for me to heel/toe. YMMV.

http://986forum.com/forums/uploads02...1586668907.jpg

If the noise occurred in both turning directions, it's unlikely to be a wheel bearing -- it usually makes noise when turning in the direction that puts weight on that wheel. One surprising thing that can cause a grinding/roaring noise when doing a hard turn is the engine mount (or possibly transmission mount). When it goes bad, it can cause the engine to move just enough to allow something to rub heat shielding or other things, and it sounds horrible!

The other things I thought of when you described instability in the wet, with unwanted rear end movement under braking, are alignment and stiffness. If you have too much (relative) front end grip and toe out, the front will be very happy under braking and turn-in, but the rear will not. Unwanted rear toe out will also be problematic, causing the rear of the car to be unstable under braking. And in the wet you really have to soften the rear end relative to the front, so that the rear of the car is "compliant" and grippy--you might consider disconnecting one side of the rear sway bar so it is effectively removed from the car. This will keep the rear end more planted, which is vital in the wet.

Thanks to everyone for your input. Please keep the suggestions coming. I'm trying to get this car figured out!

I don't have coilovers but the car came with suspension that was recently upgraded to higher performance Bilsteins and they seem to be performing well. I have always assumed that the first upgrade that everyone should make is a decent set of tires!! Is that not true? FYI - new coilovers are planned for the near future.

Since that track day in the rain, i've been practicing heel-toe on the street and it's getting better but still not nearly as easy as the 997 especially with the race pads and that crazy initial bite. I think i'm going with the Rennline pedal cover suggestion.

I'm looking forward to getting out there on a dry track to see what happens. I can tell that i'm going to love the car by the way that it drives on the street but that first track day experience in the wet was a little discouraging.

Like i said above, i'm going with the Rennline pedal covers.

Never thought about the engine or transmission mounts. I will give it a look. It is a horrible noise and i heard it again the other day during some spirited driving on the street.

I'm going to have the rear toe looked at soon but will probably leave any other adjustments until i get a chance to got to the track in the dry.