The Official 370Z Autocross Thread

[gomer_110]

Originally Posted by Anirak

Going to be racing in my first autocross event may 8th at PBIR and wanted to get some opinions on how I should prep the car for the event (mods, maintenance, weight reduction, etc.) as of now I’ll be competing in the PBIR autocross league which has no class restrictions other than cylinder number, but I am planning on racing in SCCA autocross & time trial events in the next couple of months. My car has test pipes, cat back, CAI, custom ecutec tune, springs, wheel spacers, and a gutted trunk. I am planning on competing in SCCA BSP class but I’m not sure what other BSP legal mods I will need to be competitive and what tires I should be running.

How deep down the rabbit hole do actually plan on going? BSP is not a cheap class to play in with a 370z. Also starting your autox experience in BSP could be very disappointing as many rookies find out they are bringing the proverbial knife to a gun fight.

As for a list of mods for a nationally competitive BSP build, here's a mostly complete list:

Interior
Bride Vios III seats and mounting hardware, Schroth 6-point harnesses, Robispec harness bar, Radio delete

Exterior
Factory Nismo spoiler delete, Custom rear spoiler to extent of class rules, Front fascia conversion to ‘15+ Nismo fascia with DRL delete, Front fenders trimmed for tire clearance, Custom front splitter to extent of class rules

Drivetrain
Cusco 1.5-way LSD, Nismo finned diff cover, Exedy clutch and lightweight flywheel, RJM adjustable clutch pedal, Tilton clutch master cylinder, ZSpeed clutch slave cylinder relocation kit, Z1 Motorsports poly transmission mount, Whiteline differential mount bushings

Air Induction
Stillen Gen 3 cold air intakes, Motordyne M370 intake manifold

Exhaust
Fast Intentions long tube headers, Fast Intentions cat back exhaust

Engine
UpRev ECU tuning, Z1 Motorsports poly motor mounts, Air conditioning delete, Odyssey lightweight battery

Cooling
Z1 Motorsports 34 row oil cooler, Z1 Motorsports power steering fluid cooler, CSF radiator

Brakes
Ferodo DS2500 brake pads, Z1 Motorsports 2-piece brake rotors (front and rear)

Suspension
AST 5200 series shocks, 1350 lb/in front springs and 900 lb/in rear springs, SPC front upper control arms, SPL rear camber arms (modified for rules compliance), SPL rear mid-links (modified for rules compliance), Hotchkis front sway bar, Rear sway bar removed

Wheels
Forgestar F14 wheels, 18x12 front and rear, Hoosier A7 tires (335/30-18)
Volk TE37sl’s, 18x10 front 18x11 rear, Hoosier H2O wet tires (305/30-18)

Not saying you need every single thing on the list or even the exact brand of part listed. Just trying to give you an idea of what goes into an almost full tilt national level BSP build. Major items you'll want to start with are suspension, aero, clutch type LSD, and the Hoosiers (atleast 315's).

For the exact rules allowances I'd recommend you take a look at the SCCA's website where you'll find the rule book.

Best recommendation for your first event/season is show up, run what you brung, and focus on your driving and worry about the mods once get a feel for where you really want to take your autoxing.

Also, if you like having a "nice" looking car, BSP may not be the right class for you.

My BSP car in its current form.

[Anirak]

Originally Posted by gomer_110

How deep down the rabbit hole do actually plan on going? BSP is not a cheap class to play in with a 370z. Also starting your autox experience in BSP could be very disappointing as many rookies find out they are bringing the proverbial knife to a gun fight.

As for a list of mods for a nationally competitive BSP build, here's a mostly complete list:

Interior
Bride Vios III seats and mounting hardware, Schroth 6-point harnesses, Robispec harness bar, Radio delete

Exterior
Factory Nismo spoiler delete, Custom rear spoiler to extent of class rules, Front fascia conversion to ‘15+ Nismo fascia with DRL delete, Front fenders trimmed for tire clearance, Custom front splitter to extent of class rules

Drivetrain
Cusco 1.5-way LSD, Nismo finned diff cover, Exedy clutch and lightweight flywheel, RJM adjustable clutch pedal, Tilton clutch master cylinder, ZSpeed clutch slave cylinder relocation kit, Z1 Motorsports poly transmission mount, Whiteline differential mount bushings

Air Induction
Stillen Gen 3 cold air intakes, Motordyne M370 intake manifold

Exhaust
Fast Intentions long tube headers, Fast Intentions cat back exhaust

Engine
UpRev ECU tuning, Z1 Motorsports poly motor mounts, Air conditioning delete, Odyssey lightweight battery

Cooling
Z1 Motorsports 34 row oil cooler, Z1 Motorsports power steering fluid cooler, CSF radiator

Brakes
Ferodo DS2500 brake pads, Z1 Motorsports 2-piece brake rotors (front and rear)

Suspension
AST 5200 series shocks, 1350 lb/in front springs and 900 lb/in rear springs, SPC front upper control arms, SPL rear camber arms (modified for rules compliance), SPL rear mid-links (modified for rules compliance), Hotchkis front sway bar, Rear sway bar removed

Wheels
Forgestar F14 wheels, 18x12 front and rear, Hoosier A7 tires (335/30-18)
Volk TE37sl’s, 18x10 front 18x11 rear, Hoosier H2O wet tires (305/30-18)

Not saying you need every single thing on the list or even the exact brand of part listed. Just trying to give you an idea of what goes into an almost full tilt national level BSP build. Major items you'll want to start with are suspension, aero, clutch type LSD, and the Hoosiers (atleast 315's).

For the exact rules allowances I'd recommend you take a look at the SCCA's website where you'll find the rule book.

Best recommendation for your first event/season is show up, run what you brung, and focus on your driving and worry about the mods once get a feel for where you really want to take your autoxing.

Also, if you like having a "nice" looking car, BSP may not be the right class for you.

My BSP car in its current form.

Thanks for the info really gave me an idea of what to be looking into. As of now I’m working on getting some 18s wrapped in 265s in the front and 305s in the rear, an oil cooler, z1 aluminum motor mounts, z1 solid diff bushings, and an aluminum undershroud to replace the old torn up oem one. I’ve spent a few days looking over the SCCA solo rule book now and from what I understand my car can only legally compete in BSP with the mods I have so far. As for how far down the rabbit hole I’m planning on going I’m hoping on using autocross and time trails to get all the experience I can about working 370Zs and also to get to know some of the local garages and teams that compete since I’m hoping on working in the industry after graduating.

[gomer_110]

Originally Posted by Anirak

Thanks for the info really gave me an idea of what to be looking into. As of now I’m working on getting some 18s wrapped in 265s in the front and 305s in the rear, an oil cooler, z1 aluminum motor mounts, z1 solid diff bushings, and an aluminum undershroud to replace the old torn up oem one. I’ve spent a few days looking over the SCCA solo rule book now and from what I understand my car can only legally compete in BSP with the mods I have so far. As for how far down the rabbit hole I’m planning on going I’m hoping on using autocross and time trails to get all the experience I can about working 370Zs and also to get to know some of the local garages and teams that compete since I’m hoping on working in the industry after graduating.

The only mods you've done that are an obvious straight to BSP are the test pipes and maybe the gutted trunk depending on how gutted it is. Even in BSP you're only allowed to remove trunk/hatch area parts that are meant for normal removal. Plastic trim pieces and such have to stay.

If you're willing to go with some rules legal, high flow cats you'd be able to run in STU which requires a little less prep.

Good luck on getting into the industry.

[_soyyy]

Question. When others on the FB group talked about going square for better handling, did they mean square on the wheel and tires OR just the tires? I was thinking of going 18x10.5 +15 on 275/40/18 all around.

[JARblue]

Wheels and tires. Just tires doesn't make sense - if you're going square for performance, square tires on different sized wheels means one set of axles isn't fitted with properly sized tires, compromising your handling. The other reason people go square (or more accurately, one of the additional benefits) is the ability to rotate your tires. You're not gonna be able to do that if you don't have square wheels also. Well, I guess you might depending on the wheel fitment, but you certainly wouldn't want to.

[_soyyy]

Thank you so much! I am set with Square on wheels and tires. I appreciate the help!

[Brendan]

Originally Posted by gomer_110

The only mods you've done that are an obvious straight to BSP are the test pipes and maybe the gutted trunk depending on how gutted it is. Even in BSP you're only allowed to remove trunk/hatch area parts that are meant for normal removal. Plastic trim pieces and such have to stay.

If you're willing to go with some rules legal, high flow cats you'd be able to run in STU which requires a little less prep.

Good luck on getting into the industry.

Agree. If you're just starting, put the cats back on and do stu for now. You're still learning and it's better to have less to think about.

[Gearhd79]

hi everyone, getting back into STU AutoX seeing what anyone/everyones up to with current STU builds. looks like the 370 platform was at least top 6 at Nat's for 2021. Any info would be great thanks

[Brendan]

A few of us have pretty detailed build threads. Mine is pretty close to the top in the member gallery area. There's also an Stu thread a little ways down.

[Gearhd79]

Thanks, Ill check it out.

[gomer_110]

With the shake up in street prepared classing starting in 2023 making our cars much more competitive, anyone thinking about making the jump?

Here's a video of my runs from Solo Nats. While I ran in FP, other than gutting the hatch area it was a BSP car.

[Averying]

Originally Posted by gomer_110

With the shake up in street prepared classing starting in 2023 making our cars much more competitive, anyone thinking about making the jump?

Here's a video of my runs from Solo Nats. While I ran in FP, other than gutting the hatch area it was a BSP car.

What’s changing to make our cars more competitive? Haven’t kept up with rule changes


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[gomer_110]

370Z's are now in DSP. The primary car we're up against now is the RX8. We finally won't be up against Miata's.

[buzzyng]

Wow, I've just spent about 2 days reading through this massive thread and have so many questions :-) Grateful for all the info provided.

My situation - I have a 2010 370z Nismo that my dad gifted me. It has about 20k miles and only drive it in nice weather. I've never had any interest in tracking the car as I've been racing motorcycles competitively for a long time. After an accident last year, my motorcycle days are now behind me. I recently went to a 3 day track driving event that included autocross. Oh my gosh, I missed out for all these years. So now I want to dive in.

The car has the stillen dual long tube intakes and cat delete but everything else stock. I was looking at upgrading the radiator and an oil cooler to do track events but am worried about being put in an AX class that is really meant for highly modded cars. Where is the best place to be competitive without spending alot.

I have a C8 that I could use for AX but I liked the idea of a smaller more compact car but really not sure the best approach. Appreciate any insight or guidance. thanks

[Averying]

Originally Posted by buzzyng

Wow, I've just spent about 2 days reading through this massive thread and have so many questions :-) Grateful for all the info provided.

My situation - I have a 2010 370z Nismo that my dad gifted me. It has about 20k miles and only drive it in nice weather. I've never had any interest in tracking the car as I've been racing motorcycles competitively for a long time. After an accident last year, my motorcycle days are now behind me. I recently went to a 3 day track driving event that included autocross. Oh my gosh, I missed out for all these years. So now I want to dive in.

The car has the stillen dual long tube intakes and cat delete but everything else stock. I was looking at upgrading the radiator and an oil cooler to do track events but am worried about being put in an AX class that is really meant for highly modded cars. Where is the best place to be competitive without spending alot.

I have a C8 that I could use for AX but I liked the idea of a smaller more compact car but really not sure the best approach. Appreciate any insight or guidance. thanks

Is it also a street car? How much do you care about being competitive vs just showing up and having a good time? What tires are you on? I believe the cat delete puts you right to street prepared category which means the competition will be on slicks.

Running in XSA might be a more reasonable class if you want to leave the cats off the car without going too far down the ‘racecar’ rabbit hole. It allows a minimum tread wear of 200 (more streetable tires) but whatever engine/exhaust mods you want.

Oil cooler upgrade is a must for any 370Z. You don’t need the radiator upgrade for autox but might be a good idea for the track.

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