"Also, we were able to secure a pre-production AEM CDI ignition, which is an updated version of the original CDI, which has experienced some reliability problems. The new ignition box is stronger, more reliable and worked without a hitch.
"Testing with the new fuel supply we were super frustrated to find that the larger turbo at higher boost was not making any additional power over the previous GT35R setup. It's a real shock to put on a bigger turbo and get no return on investment. This was super frustrating and we obviously needed to go back to the drawing board to find the missing power. A turbo system is like a chain, it's the weakest link that sets the limitation and everything must work in coordination to realize optimal power."
Gremlins"Examination of the AEM EMS datalogs is a great trouble-shooting tool that can give you virtually unlimited information about how your car is running. In this case the air intake temps were identified as a significant problem. The previous intercooler was ideally suited to the GT35R and was showing its limits with the 40R. The charge temps were suddenly rising to over 180 degrees because of the restriction caused by the intercooler. A Buschur Racing 'RACE' FMIC kit, which somehow manages to directly bolt into the factory location and yet is rated at an astonishing 1,150 horsepower was positioned at the leading edge of the Evo."
Proper intercooling serves two purposes. First, it lowers the intake charge temps which results in a denser charge and more power because there is more oxygen to burn. Secondly, lower air charge temps enhance the process of combustion and improves detonation resistance allowing for a more aggressive tune while maintaining a proper safety margin against detonation.
Another aspect of intercooling is pressure drop; the loss of pressure as measured from the turbo discharge to the intake valve. The lower the loss of pressure, the less you have to crank the turbo to achieve a given boost level and, therefore, less heat will be generated in the intake charge.
Beyond the FMIC review, the AEM datalogs showed that the restriction included more than just the chiller. It showed the old 2.5-inch intercooler pipes were becoming a significant issue, the intake manifolds suddenly became a serious problem as they started to pop like balloons under the stress of 40-plus psi of boost from the GT40R turbo. And there may be issues with the stock throttle body.
The solution was a new set of Buschur Racing stainless steel 3-inch intercooler pipes, Accufab 70mm throttle body and AMS intake manifold. The AMS unit is superior to other designs currently available as it is constructed from super thick metal. Also, its superior design creates a wonderful compromise between low-end power and top-end breathing.
The newly released re-designed Accufab throttle body has a new multi-piece shaft design which is stronger than previous designs which have been noted for frequent failure in DSM applications.
Clutch"As soon as we strapped the car to the dyno with the new intercooler and throttle body setup we realized that it was going to be wicked wild," says Al. "The clutch slipped like crazy and the dyno recorded over 700 whp. Exedy has been working super hard to keep up with the clutch demands of the power-hungry USDM market. The unit we were using was a triple twin carbon clutch with the soft street-style pressure plate.