flatlander937's Mazda2 build - SCCA STF / NASA NXF

Looks GOOD, Flatlander937!

Thanks!

Awesome! Hopefully in the not too horribly distant future koni will make bolt in front struts for those of us less talented.

They already do, for the Fiesta. Just use a Fiesta lowering spring set to match the perches. They're very similar vehicles so I doubt ride height will be much different than advertised, maybe 1/4in higher than advertised on a Fiesta I'd guess.



So anyway got the pull figured out... The REAR brakes were not adjusted evenly left to right! I figured it out by pulling the ebrake and finding it yawed to the right just like under hard braking. Very odd. I'm guessing the old suspension was so soft and compliant compared to now, with the higher rates causing much quicker weight transfer making it hypersensitive to force differences left to right.


I cut another inch from the rear bumps. Rides really well. I played with caster adjustment and fine tuning camber and reset toe, if some math formula I found is correct I've got about 3.6 deg caster on left, 3.8 right, and 2.4 deg camber on both sides, and set to zero toe.


Ride heights are 23-5/8 in front, and 23-7/8 in the rear.


Now I'm playing around with the shock rebound adjustments, feels great 90% of the time. Only problem is highway speeds, the rear bounces a bit with expansion joints. Not like Honda cut springs bounce, but I think it can be improved/eliminated.


With no front sway bar it has tons of grip in cornering, even under acceleration.


I was jacking it up to adjust the brakes and took this pic to get a rough idea of roll stiffness, front both wheels are on the ground, body just slightly tilted, both rear wheels off the ground. DDM bar in the rear still.

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And I need to wash it, I think I'll enter the Mazda of the Month since this month's theme is "suspension and wheels."


Will see about getting some gopro footage soon. I plan on using it to help with shock tuning.
 
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MOTM for suspension? Make Tony and Zach share it. They didn't start with a kit, they engineered their own!
 
Thanks guys, yeah I'm entered.

Been fiddling with the front shocks some. I think another 100lbs up front could work, not maxing them out yet.
 
Made it the 600+ miles to VA Beach without destruction. I wish I had raised the rear ride height some since it was loaded down, was great for 95% of the roads, but beat me to death on big bumps and wavey pavement stretches of highway, suspect from hitting the bumps.

Here are a few pics from the trip there:

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So been daily driving my 2 100mi/day for the last two weeks. It beats you to death on the roads around here, primarily on all the bridges and stuff on 264/64.

I found that running my snow tires makes it way more tolerable so I've been just burning them up on my commute:

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It's squirmy as hell but better than being fatigued just driving to/from work.


I signed up for an autocross event tomorrow with the Old Dominion SCCA in Pungo so I'm looking forward to doing that. I am anticipating that body roll will be excessive so after the event I'll probably be swapping the stock suspension back on so I can weld sway bar brackets onto my front strut housings.



Did a string alignment today by maxing out front camber and running zero toe up front.


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The STF class here is basically non-existant. It may dictate a change in auto-x cars (or class) in the future. We'll see...
 
Geez, totally forgot to update the build thread here:

I autocrossed it a few weeks ago...


Loved it. Paxed 10/46 and raw timed 23/46. I was driving what should have been the slowest car there(by PAX, no HS or other STF present).

I need to add a front sway bar I reckon to test that out, but honestly it was just stuck to the ground. No over or understeer. I ran 37 and 38psi, let the rears get higher with each run, kept fronts at 37 each time trying to induce oversteer but it just gripped more each run.

It's a very bumpy lot, didn't feel a damn thing really in the car, never got upset with course imperfections etc.

The answer may be more front spring and tad more camber. I estimate I was around -2.5.

Edit: fastest run

https://youtu.be/327wedwOltA


Also I've put 4500 miles on my suspension like this with no problems or catastrophic failure. Yay!! I put stock suspension back on for now to pass state inspection, I may or may not bother adding sway bar tabs for the time being. Not feeling like tearing down the strut housings to prep for welding. Will likely postpone until winter when I can send the inserts off for a rebuild and rears out to be converted to externally adjustable.
 
Got my DDMWorks intake and short shifter today :)

Also got an oil sample kit from Blackstone Labs so I can take an oil sample(0w20 Pennzoil Platinum running a PureOne filter) and evaluate engine wear/etc. Will be sending it off when I change oil one of the next 2 weeks, and will install the DDMWorks parts at the same time.

I'll be doing a second analysis in a few months again to make sure the air filter is doing it's job of filtering/compare filtering efficiency vs stock. Then switch to Redline for next season and see how its UOA comes back.
 
Ran last weekend with the TSCC again this time at ACU-4... by far the most scenic course I've seen!


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Also got magnetic numbers finally! From IZoomGraphics. They were great to deal with!


Results: http://www.tidewatersportscarclub.com/results/2015/151018_results.html


Paxed 26/103 and raw timed 49/103.


Cold temps didn't help me running early in the day but it is what it is. I was super happy with results of my raw time vs a lot of STX and STU.


Also this was my first event with a DDMWorks short ram intake... Makes a big difference above 3500rpms.

Makes me REALLY want an exhaust and moreso a tune.


And video of fastest run:

https://youtu.be/UzSZ3uZAdBc
 
Have you tried HS class before doing all of these mods? I am auto-crossing my 2 in HS. I can't beat the powerful Fiesta ST's, which are oddly in the same HS class, however I do come close at about 5 seconds slower considering I had used up, mismatched all season tires on a completely stock car. 41 sec (FiST) vs 46 sec (M2).

I'm on the fence on deciding whether or not I want to go STF, or stay in HS. In HS, I am not allowed to modify anything except add one sway bar and change the rims and tires (matching stock wheel sizes and normal tire wear ratings). However, I would like to install wider and larger light weight 16" x 7.5" wheels for aesthetic and handling reasons and I would like to lower my car 1". This would knock me out of HS and force me to spend thousands more to be competitive in STF.

If that is the case, what do you think about Mazda's B-spec package? Does it meet STF guidelines?
It comes with the following:
Front & Rear Shocks (Bilstein w/ special valving)
Race, Helper springs and spacers
Front sway bar end link
Rear Sway Bar (adjustable)
Front crash/camber bolts
Front & Rear Brake Line Kits (Stop-Tech)
Cat-Back Exhaust System
Air Filter (Green Filter)
Oil Cooler Kit (sandwich style oil cooler)
A/C Delete Kit (idler pulley)
Kit Price: $2575 US
 
Hello C7SCayman,

Please don't take this the wrong way, but there really is no other approach for me to break this to you. When you are off pace by ~5 sec compared to another car in your class (ie. the FiST) in a 40-something second course, you are not anywhere "close". Even if you are 0.5 sec off pace against someone in your class, you are still not that close. If you are 0.05 sec off pace against the class leader, then you are close -- ie. only then would you be considered competitive in the class.

Off the top of my head, I don't think the oil cooler kit nor the A/C delete are legal in ST*, but I'd have to verify to be sure.

The autox-ing regulars all know that the car is way more fun to drive in STF than it is in HS, so the fun factor question isn't really a question at all. For myself at least, the move from HS -> STF would be evaluated as follows -- given the $xxxx that I can afford to spend on STF upgrades:

1) will I get a faster PAX time in STF, compared to the PAX time I get in HS?
2) which class will I have a better chance at winning?

For me and my very modest budget, I know my STF PAX time is still going to be much faster than my HS PAX time. Plus, I'll also benefit from a lot of the STF upgrades even when I am not autox-ing the car -- case in point, the additional power from the power mods are all very much appreciated. So for myself, the move to STF is a no-brainer.

Last but not least, if you are considering a wheel upgrade to 16x7.5, consider your preferences between looks and competitiveness. IMO, the competitive size for our 2 in autox should be 195/50/15 or 205/50/15. Going 16" will add unsprung weight and make you slower. So if you are serious about winning, stick with 15" wheels and tires. If looks are more important, go with the wheel size that you like.
 
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