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Aspiring Mad Scientist
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1,716 Posts
Discussion Starter #1 (Edited)
Color0's Build Thread -- The Daily Downhill

I wanted to post some new pictures but decided not to clutter up the various forums I've already posted in, hence from now I'll be consolidating everything, pics, data, reports, etc. in this thread. I humbly present my Indigo Lights Mazda3 Skyactiv. :)



Modification list:

Power/MPG:
  • Cut-airbox SRI
  • JBR Skyactiv Panel Filter
  • Custom Magnaflow 11132 exhaust w/ 3.5" exit
  • Ford E-Focus Rear Motor Mount
Chassis/Suspension:
  • BC Racing ER Coilovers w/ custom digressive valving
  • Swift Springs 9kg/mm F
  • Hyperco Springs 650lbs R
  • SPC Rear Camber Arms
  • Corksport 28mm RSB
  • Hotchkis Billet Sway Bar Brackets
  • Corksport Rear Toe Links
  • Tri-Point Rear Endlinks
  • Powergrid Front Endlinks
  • GTSPEC Front Strut Tower Bar
  • Corksport Mid-Chassis Brace
Brakes:
  • Mazdaspeed3 front brake conversion
  • Mazda5 rear brake conversion
  • Stoptech Street Performance pad set for Mazdaspeed3 F/R
  • Stoptech stainless lines F/R
  • Edelbrock speed bleeders
Wheels/Tires:
  • Enkei NT03+M 18x10.5 +30 F/R
  • Bridgestone RE-11 285/30/18 F/R
  • Touge Factory hubcentric rings
  • Eibach 10mm spacer F
  • Adaptec 12mm spacer R
  • ARP extended wheel studs
  • Muteki SR48 Burning Blue Neon lugs
Exterior/Aerodynamics:
  • Garage Vary Replica Front Lip
  • BMSPEC birch plywood front splitter
  • 240ZG Fender Flares (4x fronts)
  • Bayson R side skirts
  • SPMS P1 Spec Rear Wing
  • BMSPEC custom wing endplates
  • BMSPEC custom wing risers
  • BMSPEC custom rear diffuser + subframe
  • VG Sharkfin Antenna
Interior:
  • BC rear damper remote adjuster
  • Custom eccentric aluminum shift knob
  • Works Bell steering wheel hub
  • Momo Mod.08 steering wheel
  • Custom clamp mount for OEM airbag+horn
Lighting/Electrics/Misc:
  • Rustoleum Satin Black headlight housings
  • Hella Optilux Extreme Yellow 65W 9005 high beams
  • Hella Optilux Extreme Yellow 55W H11 low beams
  • SuperBrightLEDs 7443 turn signals w/ load resistor
  • Corksport LED Hatchback Brake Light
  • Brake light flasher circuit
  • Hella Supertones
  • Rear wiper delete

Chassis setup (will update numbers as I find information):
  • Front Dampers: 8 Bump/14 Rebound (clicks from hard)
  • Rear Dampers: 0 Rebound (clicks from hard)
  • Springs: 9.8k F/10.7k R, 6" all around (1/2" tall helper in front)
  • Front strut height setting: Max Low
  • Preload from Max Low (# turns): 2 FL / 4 Fr / 4 RL / 2 RR
  • Droop: 1.5" F/1.5" R
  • Front Sway: Stock
  • Rear Sway: 28.5mm bar @ 1025lb/in setting
  • Front Endlinks: +0" length from stock
  • Rear Endlinks: +1" length from stock
  • Bumpsteer Correction: None
  • Ride Height: 25.4" F/25.5" R (Fender-to-ground measurement; half tank gas, stock-diameter tire)
  • Camber: 2.5 F/2.3 R
  • Caster: 3.0 F
  • Toe: 0.00 F/0.02 R
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10/5/2012: Story begins. I had a Graphite Mica 2012 Skyactiv3 before the current blue one, however the 6AT decided to leave gear as I was trying to leave the freeway. With techs not finding any error codes and Mazda not offering any help at all (too new of a problem), I decided to bite the trade-in depreciation and swap the 2012. Turns out, Sierra Mazda had a gorgeous 2013 Indigo Lights Blue fresh from the port. The specs were right, the negotiated price was fair enough, I jumped on it.

1/21/2013: 18x9.5 +45 with meaty tires? No problem. With a 1/2" fender pull and an Eibach 10mm spacer, it looks great. We just needed extended studs so I could actually drive lol.



The rear worked too, with space to clear in case of passengers, bumps, or going slammed for the show car look.



1/31/2013: Everything was going well so I pulled the trigger on a pair of custom 8mm spacers from Adaptec Speedware. I had Evasive Motorsports install some RX-8 10mm extended studs into my front hubs to allow the use of the spacer.



Upon driving the car though I found a LOT of rubbing when cornering, and isolated the problem to the fender/bumper junction. With a knife, a drill, and a little heatgun work we got that sorted out.



Useful trick I discovered: putting shims between the fender and bumper mounting bulkhead outwards will widen the entire face of the Skyactiv3. Way more clearance than before and cleaner looks to boot!





2/19/2013: Learned to hammer in my own fenders with a ball peen in order to move the last corner of metal (where the paint was rubbed off) out of the way.



Rubbing solved! At least on the 245's.





I started to drive canyon roads a lot more as it was fully functional despite the ride height, and not slow for the 340 treadwear RE760's. I learned somehow that I could flick out the tail without wiping out or any real screwup. Driving this thing is intoxicating! Entering a corner at 2x the speed limit is entirely safe and there is reserve grip left to avoid accidents.



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Of course, it had to go wrong somewhere. Dom and I decided to have a run in the canyons, and everything was a blast up until we were about to leave the mountain, when a rock showed up out of nowhere (wasn't there during our scout run)! Long story short, the rock was 4" tall, I misjudged my own ride height/lack thereof. The rock seemed to deflect off my undertray into the front left wheel, shattering the rim and bending it upwards, bringing my strut clearance to zero and my night to a rather abrupt end. The broken wheel still hangs in Dom's garage.

My next week becomes pretty fun, as in the span of 72 hours I order -- and receive -- one new RPF1, four new Michelin Pilot Super Sports (yep... caught the traction addiction) and generally prepare to have stuff overhauled....

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3/09/2012: With my car repaired, upgraded (the Super Sports are BIG!) and somewhat up and running (and a chip in my front strut... -_-), plans commence for a custom axle-back exhaust. I hated how the stock exhaust system seemed to go full retard after crossing the rear axle line, not only turning a full 360 degrees but also dropping tubing size from 2" to 1.75":



So I did something about it, designing this:



Making sure Chris at Castro Motorsport knew what I was looking for. I spec'd 50mm piping all the way through in order to maintain high exhaust velocities at partial throttle, all in a bid to maximize partial-throttle torque and fuel economy.

Sorry for lack of pics (old host down), but it came out exactly as planned. I have just the right amount of aggression to let people know I exist, yet it's not obnoxiously loud and not super-deep like most options you'll see for this car.



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4/13/2013: The Pilot Super Sports I ordered were not 245/35/18, but 255/35/18 as I wanted to avoid stretching tires. However, not only are they taller and wider than the RE760's but PSS also run wide on their own, effectively making it a 265-wide tire. Great if you can fit it, but terrible if you are already pressed for space like I am. Rather than banging more on the fenders, I raised the car back up using SWIFT springs, 8k/178mm/65mm up front and 6k/152mm/65mm in back. Picture by DomTheGhost of the front springs. Swift = orange, BC = black.



The old BC springs were 160mm long in front and 130mm long in back, so the new springs (178/152) necessitated a lot of collar adjustments in order to preserve my corner balance, damper preload/droop/static position and allow the springs to be wedged in there in the first place.

At the end of the day, the final ride heights that I'm sitting at now (averaged left/right because of corner balancing) (ground to fender measurement):

Front: 25.6" (~1.5 finger gap)
Rear: 26.0" (~2 finger gap)

There is still a good drop, but nowhere near extreme anymore. The car became stable to a point that my balance again shifted towards understeer, so I put the 24mm rear sway on the stiffer setting. I am thinking I may want to get a stiffer rear bar at some point but am pretty happy with where the car is for now.

4/21/2013: And here we are today. I do wish it were low still, but this setting is the fastest downhill I have tested so far and it is nice being able to clear speedbumps while toting passengers.



It's still quite understated looking and sounding, and the cops don't give me much attention for it.



Camber is -2.5F, -2.0R. With the underinflated tire pressures I like to run in the canyons it promotes progressive oversteer without rolling the tire onto its sidewall and possibly damaging it.






I will stop here for this first post. :) All updates from here on out will be full-flavored! To continue reading my story you'll have to scroll through all the pages of this thread, sorry! :D

 

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Thundercougarfalconbird
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2,450 Posts
looks amazing! i love seeing worked SA's. now how was the weight difference between the stock wheels/tires and your oversized RpF1s? i would assume they weigh more but idk.

i wonder if u got OEM sized RPF1s how ur gas milage would go but that was another thread.

much love for your sky!
 

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Aspiring Mad Scientist
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1,716 Posts
Discussion Starter #7 (Edited)
To almost everyone's surprise, PSS are a very light tire. I don't have a scale so I'm working off manufacturer numbers, but the RPF1 + PSS combo is somewhere in the 41-42lb range. For comparison's sake the stockers are 40-41lbs per corner, so there is not a whole lot of difference. Certainly I can't feel any difference in weight when I'm working on the car.

However, there is no clearance everywhere lol, have you ever maxed out the inner wheel well in the REAR? :punk:



Apparently this occurs when you max out the suspension travel in the rear right, the camber gain provided by the multi-link suspension reduces my 3mm clearance to zero, resulting in the rub mark.

This is a late picture, but I had to document how the Swifts fit in the front. At full shock extension the springs can be shifted around a little (65mm ID vs. 62mm ID of the stock BC springs), so I just wanted to make sure it couldn't touch the tire. Nothing to fear here, much more room left than I thought.



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As some of you know I've been doing a lot of damper tuning recently with the BC's, most of which revolves around balancing bump damping, "fake" bump damping, and the native damping adjustment that BC offers, which practically only adjusts rebound. I hypothesized a while back that you could add "fake" bump damping by compressing the inert gas inside the shock cartridge, a trick that AutoX people use in stock classes to make the car feel like it has stiffer springs. I don't have the means to pressurize the gas cartridge, so instead I took the front struts, turned the height adjustment collar up, and the spring preload down, such that my actual ride height didn't change, but the shock body sat higher up in its travel range at static height. Theoretically, I've put more of the shaft inside the shock body, which should result in compressing the gas cartridge a bit. As a result of this change you also gain front droop/downtravel, which is super important on a FWD car with an open diff. I figured the two changes would keep the front wheels from compressing too much and losing camber in a turn.

And you know what, while it works (the front feels a tiiiiiiiiiny bit stiffer), it's also not the right kind of stiffness I was looking for -- I should've known, as compressing the gas cartridge is similar to what air suspension does, the air is the spring, not the damper. The car got bouncier over a certain good-for-tuning turn without gaining any noticeable front grip, which suggests to me that I essentially increased my front spring rate. Didn't like it, so the front preload setting is back to where BC recommends you put it, and ride height adjusted to taste. I have considered going the other way -- preload up, height down -- to see if the front gets softer, but then I will lose front droop, and considering this car already lifts up the inside front wheel sometimes I really shouldn't reduce it any further. So my front suspension settings are locked down now, save for the rebound adjustment (more in a bit).

In the rear, however, you can play with the gas cartridge all you want, and get good results out of it. I have experimented with long shocks (gas cartridge compressed, feels stiffer, more rear droop) vs. short shocks (gas cartridge not compressed, feels softer, less rear droop) and ended up liking the short shocks a helluva lot more. The softer-feeling rear reduces the amount of "twitch" steering I can get throwing the car into a corner, --but-- the reduced droop makes lift-off oversteer more easily accessible. As far as I can tell, I'm lifting the inside rear wheel just a tiny bit upon entry, and placing it lightly back down mid-corner. The softer feeling is good, mid-corner corrections were easy to meter out and the traction bias upon corner exit is more biased towards the front wheels. Basically, all in line with this wonderful article:

Shock Tuning - Neil Roberts

With the hard-to-adjust stuff dealt with, I'm now just figuring out the optimal adjuster setting on the BC's. Currently I have the shocks set to 16F/18R, that's 16 clicks from hard up front and 18 from hard out back. The ride is barely harsher than stock at this setting, and I can make it better by turning things down to 24F/26R. The fact that the adjustment knob only gives a ride quality difference with eight clicks of adjustment tells me that yes, it changes the bump damping, but not really by that much. Far more noticeable is the "bounciness" mid-corner that the softer settings induce: basically, not enough rebound allows the car to pitch and roll about over mid-corner disruptions, and that's why for spirited driving I'm currently at 16F/18R. It still bounces a little bit, but I prefer that to having too much rebound, which will pick the wheels up off the ground and induce "skipping" in the middle of a corner. I've had that happen to me several times with the shocks at 6F/8R (see signature pic, I was actually skipping on that very turn on Mulholland lol) and so I no longer run stiff settings at all. They may work on the racetrack, but in the canyons you need more bump compliance to maintain traction over all the crap you may run into on the road. 16F/18R and 18F/20R (a little bouncier) work well; I found that 16F/20R makes the car more reluctant to turn in and 16F/16R makes it understeer a little more on the gas. Again, matching everything stated in the article I linked above.

Of course, these are just my own preferences applied to the narrow scope of being fast downhill, but for 8k/6k springs, stock BC damper valving, and assuming good tires, I think that keeping the damper setting right in the middle of the range, with 2-4 clicks difference front and rear, will be a good setup for most non-turbo Mazda3's. AutoX cars will use more rear rebound to lift the rear around cones, and track cars might use less rear rebound in order to keep the load in front exiting fast corners, but I think my baseline should be a good, safe setup to start from.


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And here's my current mini-project, half-fabbing a new lip for the 2012+ Mazda3's. On the right side is an M-Tec corner "splitter" (really an air dam) that should be belonging on an E36 M3... but I bought it anyways and proceeded to work it into the piece on the left, which will eventually fit my car.



The original piece has two mounting nubs, I presume to allow you to screw it into the M3's front bumper along the underside. We don't have any such real estate on our 3's of course so they'll have to go. There is also the rather sharp corner of the M3 part that will have to be straightened out and re-bent in order for the part to match the lines of the Mazda3 bumper.



And it works, pretty well. I cut out the nubs using a dremel, and then also cut out a section of the plastic that would have prevented me from straightening out the bend. Sanded down internal ribs, etc. and then went to town on that corner with my heat gun. I ended up getting the bend straightened out really quick, however I did burn the plastic a little bit, hence the sanded down region where the burnt polyurethane used to be.



There is more bending to do, including almost rolling flat the plastic lip on the side of the air dam. If I can pull that off as well, then mounting the finished air dam to my bumper will be straightforward, drill six holes through each half of the air dam, screw in some truss head screws to use as studs, then drill twelve holes in my front bumper :wacko: and secure the air dams via nuts and washers inside the bumper. Not a project for the faint of heart, but then again it's not the end of the world if I fail and have a few extra holes in the bumper lol. At that point I'll have a proper shop do something about it.
 

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how the funk you cracked that wheel?

I think I need to get those springs too... fronts eating on my car's bra... lol
 

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I think you just need smaller sidewall tires and/or raise your car up a bit.
I played around with the setting earlier... I increased the rebound and it helped the front not to smash on my fender. As for the rear i also increased the rebound and it definitely made a difference, but the rear passenger side needs to camber in a lil bit
 

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Aspiring Mad Scientist
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Discussion Starter #12
I've got phone books and a good knife at work, Oliver... ;) I need to fix my own fender liners too anyways!
 

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I've got phone books and a good knife at work, Oliver... ;) I need to fix my own fender liners too anyways!
Lol.. Theyre pretty much gone since the last setup i had
 

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Aspiring Mad Scientist
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Discussion Starter #14
Short update, before I went on a canyon run I snapped a pic of my average mpg "sans canyons".



As you might infer from the average speed, the car drives a good bit of highway miles compared to city. I'd say it's typically equal time city/highway, but about 5:1 highway to city miles. I'm only achieving 32mpg by babying the car around town, if I don't baby it at all I drop to about 30mpg. Nonetheless, not bad considering the amount of tire this car has to push.

Also, an easter egg. For whatever reason I can't scan the code, but it's found in the engine bay. :D




I've ordered a Tri-Point rear sway to replace the Corksport item -- apparently the CS bar is just too soft for the grip and driving style I have. If you follow CS's product specs, their bar is 114% or 180% stiffer than stock, which come out to 492 and 644 lbs/in respectively; the Tri-Point bar goes to 750, 825 or 1000. From experience, the 644 setting was not quite enough, I could get good rotation off-power but on-power the car would still push if I was going fast enough. I'd like to start tuning that out now that I'm used to driving the car, so 750 should be a good starting point to tweak the balance just a little bit. For those of you following my tuning experiments, keep in mind that you will most likely want to soften the rear damping after a change like this to prevent the rear from unloading too fast when braking. I have the setting at 14F/18R right now, it dampens out my entry "twitch" steering so I expect it to play well with the new sway bar.
 

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Aspiring Mad Scientist
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Discussion Starter #17
There isn't lol. That's how they're so light for "cast" wheels. If you get these in a narrow 16" or 17" size they really are the ultimate fuel/cash economy wheel.

Tri-Point rear sway has arrived, sans retaining collars... the owners manual states that the Gen 2 cars don't need them. I'll test out that claim tomorrow.
 

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Aspiring Mad Scientist
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Discussion Starter #18 (Edited)
Gonna get this one out of the way before I forget everything tonight -- serious warning below.


The Tri-Point sway has extremely good build quality and bolted on in less than half an hour, as expected. The brackets line up with the inner edge of the swaybar "leaves" so that's why you don't need the retaining collars (learn something new every day!). I greased up the bushings nice and thin and everything seemed to be OK installation-wise. No creaks, squeaks or telltale rattles either.

Driving wise is a bit of a mixed bag. Keep in mind that everything I say after this sentence is heavily dependent on individual car setup and driver skill. I noticed immediately that the extra stiffness of the Tri-Point sway makes lift-off oversteer more accessible, and on smoother corners I had no problem modulating the rear end of the car mid-corner using just throttle inputs. Feels nice. However, what I also noticed was that the car became very sensitive to bumps: hit one the wrong way and the rear will snap oversteer instantly. I got no warning from the tires, the rear just let go on me, once going uphill in a tight right and once more going downhill in a medium left. Given that the car behaved consistently in smooth turns, I have no reason to suspect tweak or loose bolts. I'm thinking I just went too stiff.

The on-brakes behavior of this car now is also dangerous for me. With the Corksport 24mm bar, I had the fortune and luxury of being able to brake sideways, where I could hit the brake, and without changing the steering angle much, the car would slide while slowing down, and would not rotate more or less while doing so. This no longer seems to be the case with the Tri-Point bar installed. When sideways on the brakes it always feels like the car wants to rotate more, and eventually wants to point towards the cliff. I spun out twice in an hour tonight, because this over-rotation forces you to countersteer to get away from the wall, but then as you do so, the rear naturally comes back into line and fishtails you the other way. With the CS sway bar (and everything else identical) the car rotates slower, and I end up "only" facing the exit of the corner by the time I reach the apex and I can then floor the gas to exit the corner.

The Tri-Point bar does make the car rotate better in off- and partial-throttle situations mid-corner, and I suspect it would be faster on a racetrack where a car like mine would spend the better part of its life modulating the tires without needing the brakes. But in the mountains, I've lost the ability to slide on the brakes safely and I don't feel confident driving a car that wants to over-rotate all the time. I'll be faster if I can brake later and harder without sending the rear end out so fast. So it comes as a surprise to me for sure, but I don't think I can use this rear sway bar.

The Tri-Point RSB willl be up in the For Sale section tomorrow, with less than 5 hours of driven time in the car. If you have BC coilovers with 8k/6k spring rates, don't say I didn't warn you. The Tri-Point RSB could be too much for a canyon/tarmac rally application.
 

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Oh damn... I wish i was at the crest witb you guys last night!!. Does the tri-point rsb has different settings?
 
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