Tuesday, November 24, 2015

Improved Shifting, New Exhaust Note




The Mach V WRX is sometimes last in line for modifications, since we keep pretty busy modifying customer cars, but we were able to perform some more modifications since my last blog post. We installed a new Kartboy short shifter, Kartboy shifter stop, and and lovely Raceseng knob to top everything off.

The Kartboy short shifter is an interesting part. As you probably know, the WRX uses a cable shifter mechanism, which is a departure from the old lever-actuated shifters in previous WRX models. The shift lever operates a counterweighted pivot on the underside of the car, and the Kartboy shifter is a shorter version of that pivot. Unlike some of the competing short shifters, the Kartboy unit is itself counterweighted, which gives a nice feel and sense of mass to the shift motion. And since you asked, it IS compatible with the OEM Subaru short shifter available from the dealer.

Up on the inside of the car we installed a brand new Kartboy shifter lock, which limits the left-right travel of the shift lever, further tightening up the throws on the shift lever. There are other versions of this kind of part on the market, but most are made of metal, which can lead to some noise when the shift lever contacts the stop. The Kartboy unit is made of a high-strength glass-filled nylon, which is almost completely silent when the shifter contacts it. (Kartboy banged on it with a hammer to test its impact strength. It survived.) Our prototype part was black, but production parts will be yellow.

Finally, with all these improvements in the shifter action, we thought the top of the lever deserved an upgrade in the form of a nice shift knob. We chose the Raceseng Topologi, which has a massive stainless steel core with an outer layer of Delrin. We installed the red Delrin sheath for now, but might switch colors later -- the parts just thread together, so we can swap out whenever we want.

Shifter feel after these changes is light years from the feel of a stock car. The throws are short and weighty, and you can feel click-click when the lever is going from gear to gear. It takes a bit more effort to push the lever around, but it's a welcome trade-off for the improved feel.

One final modification we made to our WRX lately is to install a Cobb cat-back exhaust. I can't say enough good about this system. It fit up perfect to the factory J-pipe, it looks great, and it sounds terrific -- it's got a good growl under acceleration, but at idle it is just a pleasant murmur. It took us a while to get one for our own car, though, since demand for the new system outstripped Cobb's manufacturing capabilities at first. The supply situation has finally improved, so the systems are readily available now.

Parts referenced in this post: Kartboy 2015+ WRX short shifter, Kartboy 2015+ WRX shifter lock, Raceseng Topologi shift knob, Cobb 2015+ WRX/STI cat-back exhaust.

Friday, February 6, 2015

More Brakes!

When we last left our hero, he had taken the 2015 WRX to the race track for a HPDE event, and found the stock brakes...not really up to the task.  The car stopped fine, but the system quickly overheated, resulted in boiling brake fluid and a soft pedal.  Even before that, the pedal feel was kind of mushy and didn't provide very solid feedback.

As you probably know, the higher-spec STI comes with larger and better Brembo fixed-caliper brakes.  I decided I'd retrofit those to my WRX. Since the car shares the same basic platform, and the WRX and STI have the same 5x114 bolt pattern starting in 2015, the parts would easily swap over.  Black Brembo calipers from the 2008-2015 STI will bolt directly on. Even the earlier gold Brembo calipers from back before 2008 will bolt up; the rears just need an adapter bracket.

I sourced some used gold Brembos from a 2004-2007 STI from our local JDM importer, Virginia JDM Motors.  I got them powder coated blue, partially because they were a little dinged up, but mostly because I just wanted them to look different.  I grabbed an STi brake rotor/pad/lines combo kit that we sell, and the aforementioned adapter brackets, and bolted it all up.

Our rotor/pad kit also came with our Mach V stainless steel brake lines.  Stainless lines don't flex under pressure like rubber lines do, which makes for a more solid pedal feel and better feedback under hard braking.

The STi brakes have larger and more massive rotors, but the aluminum calipers weigh a good bit less -- the entire swap removes almost four pounds of total mass, and weight is removed from the calipers (where we don't want it) and added to the rotors (where we do want it).  The result is very solid pedal feel, and vastly improved ability to survive hard use like our track day sessions.  Plus, the brakes definitely stand out under the wheels!

Note that the stock 2015 WRX wheels will not fit over the large Brembo front calipers.  You'll have to run some different wheels, or use at least a 10mm wheel spacer in the front.  Our 18x9.5" Wicked Awesome wheels have plenty of clearance, so that wasn't an issue for us.  (In fact, we could put a much larger brake kit under those wheels, if we wanted...)



Products mentioned in this post: Mach V complete brake pad/rotor kit; Gold Brembo adapter brackets; Mach V 10mm wheel spacers.

Wednesday, November 12, 2014

Lowering, Tuning, Tracking!

We've been busy with the Mach V WRX since my last update.  We added an HT Autos lower lip kit, which includes a front spoiler, side skirt extensions, and little rear skirt extensions. We found that kit easy and straightforward to install. We used a combination of factory body fasteners plus a few additional nuts and bolts to secure the additional spoiler bits.

Next we added some prototype Mach V springs. They have slightly firmer rates than the stock springs, and lower the car down a bit. You can see the results here. The production springs will probably end up a tiny bit lower than what you see here.  The springs are designed to be used with stock struts, or aftermarket upgrade struts in the future.  We were expecting the ride to get harsher with the lowering springs, but it didn't really change very much.  Body roll was reduced, but otherwise the car rides about the same as before.  The stock shocks are quite stiff, so they don't seem to have an issue handling the upgraded springs.

We also got the car on the dyno in bone-stock form.  With no modifications at all the car made 235 awhp and 246 lb-ft.  We then reflashed the car with a Cobb Tuning AccessPort Stage 1 map, and power/torque increased to 245 whp and 255 lb-ft.  Finally, we did some custom tweaking to the tune and managed a best of 256 whp and 273 lb-ft.  Again, all of this was with factory intake and exhaust -- no hardware modifications at all.  We plan to do some intake and exhaust modifications and see if we can extract some more power from the car, so stay tuned.

Our 10th annual Mach V Track Day event was on November 8-9.  We took the WRX out to the track with no specific prep work, to see how it would fare in near-stock form.  The result was "Not bad!"  Power felt great -- no complaints there.
The car handled nicely, with a modest amount of body roll and a neutral cornering attitude -- it wasn't particularly prone to understeer, nor did it oversteer.  It felt nice predictable in terms of breakaway behavior, and we never felt like it was going to bite us with any sudden unexpected moves.  The stock brake pads did suffer a bit as they got hot, but that's to be expected for a street compound.  The tires (265/35R18 Hankook Ventus Evo V12) were probably the weakest link.  Grip was never huge, but as they heated up they started to complain audibly and the grip fell off rapidly.  Not that I really blame the tires -- they are a perfectly fine street tire, but asking them to handling hard track duty isn't very fair.

Products mentioned in this post: Cobb AccessPort, HT Autos Bottom Line Kit

Sunday, August 17, 2014

Getting started: Wheels, tint, and more

The 2015 WRX stock wheels aren't bad looking, but neither are they particularly noteworthy.  They're of modest size (17x8") and the dark gray color makes them sort of hard to see, especially on a light-colored car.  I just happen to know a nice large-size wheel that should bolt up nicely...that's the Mach V Wicked Awesome, which is 18x9.5" and a nice light 19.0 pounds.  A set of Hankook Ventus Evo V12 tires, 265/35R18 size, are exactly the same diameter as the stock tire, and 30mm larger in terms of tread width.  And even with significant increase in contact patch, we actually LOST 0.1 pounds of weight per corner!  What's not to like?  Plus, I think the wheels look great.  We did fit up two different colors -- silver and gold.  Which do you like better?

Since you asked, yes, I am looking to sell the stock WRX wheels, so ring me up at the shop if you are interested.  I'm open to selling them with or without the stock Dunlop Sport Maxx tires.

Other early modifications to the car include an all-around window tinting treatment from Matt at TNT Tint, and clear paint protection film applied by Dave at Proshield.  Do look them up if you need either service done, and tell them I sent you.

Next up for customizing was the audio system.  I spend a good amount of time in the car, and I do like my music, so I headed over to KarTunes, just around the corner from our shop, for some upgrades.  Mike and Dan were more than welcoming, and from talking to them they clearly like their work and bring a lot of knowledge and enthusiasm to the job.  They suggested I bring in my own iPod, and I was able to plug directly in to a display board in the showroom and audition the speakers with my own music.  After a bit of listening, I settled on some Focal drivers.  Focal PS 165 FX speakers went into the front doors and dash, and Focal 165 AC speakers filled in the back doors.

None of the usual suspects make a pre-made sub box for this car yet, but Subaru does offer an OEM amplified Kicker subwoofer.  We used the molded-plastic box from that, tossed out the Kicker driver, and put a JL Audio 10W0 sub driver in there.  The box was a little ringy at first, so the KarTunes guys applied a layer of sound deadening material inside the box.  That tightened up the bass nicely and cut down on unwanted resonance.

For amplification, KarTunes installed a couple of older JL Audio (300/4 and 250/1) amps I had saved just for this occasion onto a custom board on top of the factory spare tire.  The factory head unit was left alone -- it fits and is functional enough, and offers nice integration with the steering wheel controls.  A bonus, and something I didn't realize at first, is that the WRX upper dash info screen has a page that will display current song information sent to it from the head unit. Cool!

The end result is super-clean sound, with very tight bass and terrific clarity and separation.  I never did put any sound upgrades in my 2008 STI, and I always missed having really nice music in that car.  I can tell already I will really enjoy the chance to hear great tunes in this one.

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Tuesday, July 22, 2014

New car, new platform, new engine, new adventures!

Welcome to our latest blog, which is about our latest Mach V shop car, a 2015 Subaru WRX.  This blog will follow the modification of the car over time, and will share plenty of other observations and discoveries about the car.

First I should answer the question everyone asks about it, which is, "Why didn't you get an STI?"  We didn't because the WRX has a brand-new turbocharged variant of the FA20 engine that first appeared in the Subaru BRZ/Scion FR-S twins.  (We happen to own a BRZ shop car, too, which you can read about in another blog.)  The FA20 turbo is a fully direct injection engine -- not the hybrid port/direct setup in the BRZ.  All this is important to us because while the STI still soldiers on with the same EJ25 engine we've been working with since 2004, the FA20 DIT (Direct Injection Turbo) is all-new and I want to get started tuning on it.

Sure, I miss the direct-feeling and nearly-indestructible six-speed transmission that goes with the STI engine, and the Brembo brakes, and that fancy DCCD center diff from the STI.  But besides having the new engine, the WRX is about $8,000 less expensive.  That's a lot!  In the old days (like 2008), the gap between WRX and STI was huge.  The WRX had skinny body work, skinny tires, a weak 235hp, and tiny brakes.  Now the WRX gets the same wide bodywork as the STI, gets decently-fat 235mm tires, big (if squishy-feeling) brakes, and has 268 hp.  The difference between the two cars has narrowed, at least on paper.

Our car is a Limited model, which means it has LED headlamps (wait, let me say that again: LED headlamps!), leather-trimmed seats, a power-adjusted driver's seat, plus all the stuff in the Premium model, which includes a moon roof, trunk lid spoiler, fog lamps, and heated seats/mirrors/wipers.  Of course, we got the six-speed manual.  (You can pry my manual shifter from my cold dead heads.)  Speaking of cold and dead, though, the stock shifter feel on this car isn't too great.  I understand it's a new cable-actuated unit, and shifting it kind of feels like you're stirring pudding with a really long length of PVC pipe.

We bought the car from Heuberger Motors in Colorado Springs, CO.  We got an amazing price on the car, and the transaction was very straightforward.  They even arranged for delivery right to my door.

We don't plan to run the car on the dyno just yet -- I like to follow a factory-ordered break-in schedule -- but we will be swapping on some Mach V Awesome and Wicked Awesome wheels right away, with the goal of reducing weight and increasing the tire contact patch.  I'll post photos when that's done.