Autocross: Building to E-MOD Rules

[Tamra]

Building to E-MOD AutoX rules


We're planning on competing in auto-x with our 818S, and are working through the part selection.

Our current plan is:
OBX Torque biasing/LSD
Adjustable rear lateral links ( brand tbd)
FFR supplied "R" shocks & springs ( Koni 30-1720), though looking into on-car adjustable alternatives
Kuhmo V710 (or A6/A7 once the car is dialed in) 215/245 F/R, 16" or 17" TBD on Enkei RPF1
4" overhang front splitter
Full underbody flat surface sheet
Rear diffuser
"Duck tail" type lexan spoiler to 10" projection limit
Auxiliary cooling fans for IC, possibly water sprayer for IC cooling in staging lane


We are unsure if car will be at S or R height, as we intend to street drive the car also.



What is everyone else planning on, if they intend to use the car in a similar manner?

[Buzz Skyline]

I'm hoping to race mine in SCCA autocross and other local clubs in the DC/VA/MD region. For the first year, I'm going with the basic car with no mods to speak of (yeah, I won't win, but I'll have fun!) I have an OBX LSD on my shelf that will be the first upgrade. After that, I'm going to install Racelogic traction control, then start tuning the suspension. I hit way too many cones to risk a splitter, so I'm leaving that off.

I haven't looked into tires yet, but my donor came with a nice set of Enkei RPF1s, which are pretty popular on autocross courses around here.

We have found the water spray for the IC to be pretty helpful for autocrossing our STI, so that seems like a great idea.

[Tamra]

We're actually adding the front splitter partially to protect the front of the car from cones, in addition to the added performance benefit. Not sure if it'll be ALU or lexan, but either way it'll be frame-mounted, not body-mounted, so it'll take the hit and protect the fiberglass.

[xxguitarist]

Hey Buzz,
Thanks for the input.
Before you get into the Racelogic TC system.. Check the rules for the class you intend to run. This is from the 2014 Solo rules book.

There might be some exemptions or allowances, not mentioned in the first heading of the Modified class. It's a pretty long rules section, and I haven't read it with attention to TC.


Active Automatic Braking Systems (ABS) and
Traction Control Systems (TCS) are prohibited in Modified classes B
(BM), C (CM), and F (FM). Traction Control Systems are prohibited in
Modified Class A (AM). Active Automatic Braking Systems (ABS) and
Traction Control Systems are prohibited in Modified Classes D (DM)
and E (EM), except for the original system installed on the car, which
may not be modified.

[thall818]

I am building an S and would like to autocross as well. For me, I will be lucky to get out once a year. I'm not looking to be competitive just have fun and hit some cones, loose the path, etc. If there are any requirements that would keep me from running (seats, harnesses, fire safety, etc.), please let me know.

[RM1SepEx]

I am building an S and would like to autocross as well. For me, I will be lucky to get out once a year. I'm not looking to be competitive just have fun and hit some cones, loose the path, etc. If there are any requirements that would keep me from running (seats, harnesses, fire safety, etc.), please let me know.

Mod classes require a harness

[xxguitarist]

Dan,
Where do you see the harness requirement? I'm looking but haven't seen it.
(don't doubt you, just not sure what else I'm missing)

A few things that are relevant for us in EM.

This one is good, and hidden quietly at the end of some pretty serious requirements:

Note: DM and EM vehicles are exempt from the scattershield,
driveshaft hoop, and Master Switch requirements if they are using
DOT-approved tires.


18.1F is LONG, and addresses aero allowed.
Cliffnotes:

Front splitter is OK, not too long, not too wide.

Rear diffuser is OK. Less than 25" from front to back.

Rear spoiler (note: not wing) is OK, up to 10" projection from body. Air cannot pass under this device.

Flat underbody that we were planning MAY not be allowed.

[RM1SepEx]

Right now, by rule an 818 is in AM and 5+ points are required. It has been proposed to put them in EM for 2015 where it does look like regular production belts are all that is required. I just waded through the rules again...

won't you want "real" tires to run EM next year?

I believe that you have to have 2 inch helmet clearance "broomstick rule"

the underbody is pretty flat....

[Buzz Skyline]

Regarding the splitter: Good idea. I may follow your lead. I'd hate to mangle the body panels.

[xxguitarist]

Right now, by rule an 818 is in AM and 5+ points are required. It has been proposed to put them in EM for 2015 where it does look like regular production belts are all that is required. I just waded through the rules again...

won't you want "real" tires to run EM next year?


Ah, right. Thanks, We've been acting based on the EM plan, in hopes that it'll be there (got our fingers & toes crossed for XP at some point, but don't imagine that's likely)

Not sure what you meant on the tires. V710s are a click behind the A6, but give more "fast" runs than the A6s by most reports.

[RM1SepEx]

Tires are indeed a tough choice now, the new dot tires are almost slick level performance

I don't see XP as making much logical sense, the 818 never being a production car

I hope to have my 818S autocross at our last event in September... but I can't cross my toes... :)

[xxguitarist]

Agreed that it doesn't quite make sense to run in XP, but I'd enjoy some of their allowances (aero, for instance).

My understanding was that the guys running hoosiers at nationals were on A6s, are some of them on a non-DOT-R tire?

The V710, A6, and new A7 are "slicks" by any reasonable definition. Two grooves make them DOT legal, but that's about it.

[Tamra]

Tires are indeed a tough choice now, the new dot tires are almost slick level performance

I don't see XP as making much logical sense, the 818 never being a production car

I hope to have my 818S autocross at our last event in September... but I can't cross my toes... :)


Good luck, I'll cross my toes for you. :)

You haven't mentioned your current set up/plans. I know you autocross a lot, so I'd be interested to hear your take.

[RM1SepEx]

A modified car can run true, non DOT slicks, they are stickier and would give better life, longer life under race conditions. They are made ONLY for racing! I used to run R25's on my FM car, much stickier than the DOT-R tires

http://www.hoosierdirect.com/?gclid=Cj0KEQjwx4yfBRCt2rrAs-P5vtkBEiQAOdFXbSh6B5E2UcVX2QZJvgtHFnETIJeGQ0dPc1Hm qhxZdsEaAvSz8P8HAQ

I'd rather autocross the shifter kart, it is faster and better PT for my messed up nervous system! :rolleyes: I'm also on a limited budget due to disability and I can get a ton of runs out of a $208 set of MG Greens, stickiest tires on the planet, imported from Brazil. With all of our concrete events this year I could go through 2 sets in a season. What will it cost for two sets of slicks for an 818? $3000? And I would be slower...

My 818S is predominently a street car and I'll verify setup and capability autocrossing (right now on too skinny Direzzas) in addition to trying to scare myself with the kart. RFP1s are in J Lo's future for sure in 17 diameter

Setup depends on the tires and how camber dependent they are... you can destroy a set of A6 Hoosiers very quickly if you don't get the camber correct. If I was to autocross one seriously I'd spring for the $2000 Koni shocks and do some serious test and tune data logging and tire temp measuring, on real slicks! You know how it is in autocross, run the best, stickiest tires that the class allows

[xxguitarist]

Thanks Dan,
Hadn't been able to find a page that was forthcoming about the non-DOT-R Hoosiers.

Guess there will be some decisions to be made regarding the extra requirements that apply with non-DOT tires vs the extra speed potential.
Happen to remember the A6 vs R25 price comparison, in similar sizing? I still couldn't find pricing for the race tires.

Plenty of reading to do..

[SixStar]

I could go on and on and on about this but the short version.... build the car for XP while staying legal for EM. You'll NEVER get an 818 to be nationally competitive in EMod. And even if you do, you won't beat Jeff.

[RM1SepEx]

I used to buy used R25s from some guy online. Serious ($$$$$) racers use them for setup or qualifying and then go right to new tires to race, pick them up with 80-90% of their life left at much lower cost... Sorry don't have that source info anymore, I'm sure that a search will find him.

As far as SixStar's comments, I don't really care, have no national interests/intent. It belongs in EM based on the structure and intent of SCCA's rulebook... The 818 was not designed to be an autocross beast, it's designed as a sporting road or track car. Sadly in EM you can take a tiny old sports car and modify it until it is basically a shell with a tubular cage and doesn't represent what was originally made. That's why it's a modified class. There is no reason why you couldn't cut and hack a 818 to get close but it's outline is indeed just too large to beat a well driven, well developed tiny car in EM

I have a friend with a 240 HP 1100 lb Caterham, it has to run in AM, too light for EM. But it is an absolute beast at an autocross. I drive a kart, this Caterham beats me up so much that I'm done, physically, after only 2-3 runs... That's life.

Call this guy? http://www.jbracingtires.net/hoosier.htm

[Tamra]

I don't think we have deep enough pockets or driving skill (at least not yet) to make a car that would beat Jeff Keisel and his Sprite, even if we started with a Bugeye Sprite. That guy seriously dominates! Regardless, we enjoy autocross and we are building an 818, so we want to set it up to be E-Mod legal (since that is most likely where it will run next year, since we hope to have it finished for next season) and as successful as possible on our current budget.

Six Stars, how do you recommend setting up the car for XP and E-mod? Aero options seem mutually exclusive between the two.

[SixStar]

Aero can be changed in minutes.

I've been racing with the SCCA long enough to know that EM is a placeholder for the 818 until they see a few, watch times and PAX and realize that it's much better suited for XP. Based on the numbers alone it's clearly an XP car but they're a big lumbering bureaucracy and EM was the decision that was made. They were going to just shove the car into AM!

If anyone is planning on building an 818 for local events in EM just do what should be done on every AX car, following the rules for your class; wheels, tires, diff, seat, harness, alignment, seat time. Everything else isn't needed, especially not at first. The one thing I would suggest would be a long hard look at suspension geometry and shocks. The yellows that come with the car are $30 OTS shocks that are not suited for AX, also much much stiffer springs. Like double.

[Brando]

I thought in order to be eligible for XP you need 1000 cars sold per year. Will they turn the cheek on that?

[Grintch]

I thought in order to be eligible for XP you need 1000 cars sold per year. Will they turn the cheek on that?

They currently allow some kit cars that don't meet that requirment. But there is no solid requirment/rationle for that so don't count on the 818 ever being moved to XP.

EM requirments that some may not be aware of/compliant with:
Master cutoff switch
Using DOT tires (R compounds instead of full racing slicks) avoids it.

Roll bar above the drivers helmet, min 1.5 x 0.120 or 1.75 x 0.095 tubing, with inspection hole to verify tube thickness.
Braces and portions of the main hoop subject to contact by the driver’s or passenger’s helmet, as seated normally and restrained by seat belt and harness, must be padded with a minimum thickness of 1/2".
Maybe harnesses (wording is a bit confusing).

[Tamra]

Six Star, what suspension setup are you going with?

Grintch, I'm having a hard time finding the exact specs of the 818S rollbar. I'ma ssuming it meets the minimum tubing requirements, with potential broomstick issues for some?