Aftercooler for Comptech CT Engineering TSX

Customer build write-up by J. Yan, June 18, 2010 (originally posted on TSXClub.com as “Phase 7 – M62 at its limit”).

Result: 350 whp / 267 wtq on a Dynapack dyno, K24 with an M62 supercharger at 10 psi, MercRacing aftercooler plus water/methanol injection.

Parts added in Phase 7

MercRacing aftercooler system
Custom 3″ XLR8 straight-tube cold air intake
Custom 3″ XLR8 header-back single-exit exhaust
2008–2009 K24 crank pulley
625 mL nozzle for water/methanol injection

Thanks

Josh and Jamie at Excelerate Performance – custom fabrication
Derek at Innovative Motorworks – tuning
Jose at MercRacing – aftercooler system

Installation

I started off just wanting to add an aftercooler, but I figured I’d go all out and see what the K24/M62 combo was capable of.

The aftercooler system was originally designed for the RSX engine bay, so a number of brackets had to be custom made to mount the heat exchanger and the water pump. That added some extra installation time.

Exhaust

The single-exit exhaust combines parts from Vibrant (high-flow cat and muffler) and Aero Turbine (resonator). It is considerably louder than my old HyTech cat and Comptech cat-back setup, but the tone is deep and racy with zero rasp. There was noticeable drone at 3,000 RPM, so we swapped to a larger Aero Turbine resonator, which fixed it.

Tuning and boost

Because I was running a conservative tune before, I was able to dial in more water/methanol to offset the leaner air/fuel ratios from the aftercooler and the new exhaust. That let me make the 4-hour drive to Innovative Motorworks. I also lost about 2 psi of boost from the aftercooler and the reduced exhaust backpressure.

To regain the lost boost, I added the 2008–2009 K24 crank pulley, which is 0.4″ larger in diameter than the stock pulley. It spins the M62 to 16,000 RPM at my 7,600 RPM redline and makes 10 psi of boost.

16,000 RPM is outside the M62’s peak efficiency, so along with the aftercooler we added a 625 mL nozzle to almost double the water/methanol flow. The cooling combination of the MercRacing aftercooler and water/methanol injection is spectacular. Intake air temperatures dropped significantly, and the blower stayed cool enough to touch with bare hands even after 10 back-to-back dyno pulls. By comparison, an M62 without cooling at 5 psi would be scalding hot after 4–5 pulls.

Results

After Derek worked his magic with K-Pro, the car made 350 whp and 267 wtq on his Dynapack dyno. These numbers are probably a bit high compared to a Dynojet, so I plan to do some Dynojet runs for comparison. Either way, the car is absurdly fun to drive. The beauty of the M62 is that 90% of peak torque is available from 3,000 RPM to redline, so there is power everywhere, in any gear.