Next autocross mods…help!

[Whozyodaddy]

Current set-up: 16 GT PP with Brembos. Pedders coilovers and shocks sitting low, Pedders camber plates in front with max negative camber. Adjustable front sway bar links, but stock sway bars front and rear. Stop the hop kit for the IRS. 18x10.5 HRE wheels with Nitto NT01 305’s (I know not an ideal tire, but will likely get the Re71rz next season).

What do I do next to shave some time? I’m pretty competitive, but can be faster. Any ideas on the next couple of worthwhile mods? TIA

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[Whozyodaddy]

For reference, this is Gypsy:

 

[Unbridled5.0]

I'd get the sway bars and start playing around with them. 2/3 of the body roll is in the bars.

 

[NightmareMoon]

It really depends what your goals are.

to get faster, best thing is to find a fast local to ride along and give you advice.

what is the car doing which you want to correct? Does it slalom well? Does it corner? Does it brake and put power down?

 

[Whozyodaddy]

Good questions….. I don’t know if I have the best answers unfortunately. I think I can improve in each of the elements. I will have someone ride with me again and see if they can provide some more feedback.

I don’t have much body roll as the suspension is very stiff. The challenge generally is keeping the rear in line. I typically have decent front end grip, but the rear is a fight. Wondering if adjustable rear camber arms would be worthwhile. I’ve probably got a degree and a half currently being lowered. I think a better tire will clearly help too.

Obviously each course has its nuisances. Last event I was pretty competitive with Porsche guys. This time, on a different design, I was much less competitive with the same group. Part of problem… I compare my big fat girl and aggressive style to the German engineered track oriented cars

 

[kz]

Current set-up: 16 GT PP with Brembos. Pedders coilovers and shocks sitting low, Pedders camber plates in front with max negative camber. Adjustable front sway bar links, but stock sway bars front and rear. Stop the hop kit for the IRS. 18x10.5 HRE wheels with Nitto NT01 305’s (I know not an ideal tire, but will likely get the Re71rz next season).

What do I do next to shave some time? I’m pretty competitive, but can be faster. Any ideas on the next couple of worthwhile mods? TIA

Lowest hanging fruit - always the driver. Ride with others, go to events with good competition (not the Porsche ones).
Car mods don't ever bring the time improvements people think they do.
First thing I'd get some 18x11" from Apex and RZs and throw the Nittos very very far away. Bars are cheap and easy DYI mods for fine tuning that take little time in the garage to do, so they're no brainers.

Car has all the rear camber adjustment you need from factory, aftermarket camber arms make it quite a bit easier to adjust. Set it 2 degrees or so.
What are your spring rates and damper settings that you have trouble with the rear (might be driving - RWD car will oversteer if you mash the throttle and there may be nothing wrong with it) .

 

[SBR70.3]

Agree with sway bars. While I do not autocross my Mach 1, I noticed a huge improvement in cornering on track after installing the Steeda Comp bars.

Also......ya.......toss those Nittos.

 

[Whozyodaddy]

Lol! Thanks for the input! The Nittos were a cheap used option, so I gave it a shot this season. I read the reviews and knew they weren’t ideal, but they were actually a significant improvement over my last tires. They are done anyway, so I’ll be running new rubber next season.

I will pick up some more passengers for feedback. I guess my thought was to get the car dialed to a point where it’s very solid and I can really focus just on my inputs.

Per Pedders, the spring rates are Front - 391 lb./in.; Rear - 782 lb./in.

Besides more seat time and coaching, it sounds like perhaps sway bars and tires are likely the most beneficial additions. .

 

[mavisky]

That's a 150-200lbs soft for the front end compared to what most of us are running and on the higher end in the rear of what most run on a divorced setup on the rear. This may explain some of your isssues with keeping the rear of the car under you being a challenge. For example I'm on the higher end of the spectrum with a 700F/900R setup paired with Steeda competition sway bars set to full soft on the rear and about mid-way on the front. If I got my coilovers in their "street spec" they would be a 400F/600R setup.

As always drive time will always be a big shift in results. I really improved this year by focusing on identifying my apexes and making sure that at the apex I'm in a position to get back on throttle. I was often overdriving and trying to carry too much speed through the apex and that left me either off throttle or even on the brakes past the apex to get the car rotated. This was burning time for me and cleaning this up helped drive me towards the top of our PAX and Raw time leaderboards against national champions in our region.

 

[RobZ71LM7]

Good questions….. I don’t know if I have the best answers unfortunately. I think I can improve in each of the elements. I will have someone ride with me again and see if they can provide some more feedback.

The fact that you can't articulate what the problems or opportunities with the car are indicates you need more seat time. Focus on that with decent tires, then change the car. This isn't meant to be negative, but rather a sign you can gain a lot of time and for only sweat equity. Seat time, tires, verify you have a good alignment, drive for a year and then decide on mods.

 

[NightmareMoon]

Be careful with swaybars. If you go too stiff in the rear, your problems keeping the rear in line will get worse. Get the right balance between front and rear swaybars and you can recover some rear grip (at the expense of some front grip)

• When tires get old, you may notice more oversteer on exit. If these nittos are shot, that would be consistent, so I'd get your next set of tires on the car before trying to dial in the handling.
• You should be able to get some corner exit grip by adjusting your front rebound to be a bit stiffer.
• If you're driving with an aggressive throttle setting, consider putting it back in normal. Twitchy throttle mappings don't make autocross any easier.
• Any time you're even thinking of adding power in a corner exit, you need to be actively unwinding (straightening) the steering wheel. That's a very common new driver error. You never learn on the street to practice this, because you're not at the limits on the street (until you are and hit a curb with the rear of the car). Gotta coordinate inputs or the rear just gets overloaded as soon as you try to add power. That's not a problem parts should fix, its a driver thing.

Yes your spring rates are a bit low, yes your wheels are a bit narrow. Car is probably too low too. There's 15 additional things we could nitpick, but using the adjustability of your existing coilovers and adding some aftermarket swaybars the next things I'd play with after tires.

Post an alignment sheet if you have one.

 

[Whozyodaddy]

Great feedback, thank you! I will look into the options suggested. I fully understand that there is no replacement for seat time, however, I also believe that having a decently set up vehicle is an incredibly helpful baseline and will allow me to focus on being more efficient and effective with this particular vehicle.

I am fairly competitive with the vehicle as is on a local level, but know I can definitely tighten things up. I will continue to drive and focus on the elements of each course, pushing for fast lines and proper technique within the six or so runs available.

To articulate a little more…honestly, I feel like the chassis is too stiff currently, which may be just poor setup and being too low. There is very little body roll on the car and I feel like that is causing too much work for the tires and it to wants to rotate on hard corners. Likely because I’m probably lacking good weight transfer. It’s not absorbing variations in the track surface and not moving much under braking and acceleration. The tires are also 40 series, which isn’t awesome. The next set will likely have to be 30-35 series obviously.

The car brakes well with the Breand puts power down decently when I’m careful with the throttle. Second gear is typical all the way through the courses in this area. Most of the other issues are just driver induced.

No current alignment data. The last one was a very generic street alignment at a tire shop for my daily driver wheel set. Looking for a good alignment shop locally currently. The car isn’t a dedicated track car, but I know I need a more aggressive alignment.

Thanks again!

 

[mavisky]

I could see the rear of the car not moving enough with your combination of spring rate and swaybar out back, but setup wise I run much bigger front bar and much more apring rate. It did change the way I drive the car so dont expect it to handle like stock. My car is neutral mid corner and a little oversteery on corner entry but its all within reason and loose can be fast if you can use it to get the car rotated.

Seat time is crucial but I do agree that sorting out the baseline is best as driving a poorly setup car can just lead to you learning bad habits.

If youre want into solve problems with parts I would look at more front apring or less rear spring, alignment, and tires as my immediate solutions. I would also raise the car as it shouldn't be tucking tire at a stand still. I run my car lower than most and im still a good bit higher than yours comparing tire to fender gap. I would start your alignment with 0 toe front, a small amount of toe-in at the rear. -3.5 degrees up front and -2 out back and go from there. With a proper alignment and good tires like the stones youll likely also find yourself running less tire pressure hot than you currently are which will also help with grip levels.

 

[Whozyodaddy]

I could see the rear of the car not moving enough with your combination of spring rate and swaybar out back, but setup wise I run much bigger front bar and much more apring rate. It did change the way I drive the car so dont expect it to handle like stock. My car is neutral mid corner and a little oversteery on corner entry but its all within reason and loose can be fast if you can use it to get the car rotated.

Seat time is crucial but I do agree that sorting out the baseline is best as driving a poorly setup car can just lead to you learning bad habits.

If youre want into solve problems with parts I would look at more front apring or less rear spring, alignment, and tires as my immediate solutions. I would also raise the car as it shouldn't be tucking tire at a stand still. I run my car lower than most and im still a good bit higher than yours comparing tire to fender gap. I would start your alignment with 0 toe front, a small amount of toe-in at the rear. -3.5 degrees up front and -2 out back and go from there. With a proper alignment and good tires like the stones youll likely also find yourself running less tire pressure hot than you currently are which will also help with grip levels.

Beautiful car! I appreciate the information. I think you have given me a good start for the off season. I’ve probably got two more events that I can get to this season though so I’m tempted to start work on it now, lol! It would be nice to keep the 10.5” wheels I already have, but it seems like the 11” is just the way to go. Thanks again!

 

[mavisky]

If anyone made a 325 worth really using id be buying 19x12's but not on the Vitour train just yet. These Bridgestones have been so much better than thr Yokohamas for me.

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