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