Feb 26, 2009

Switzer Performance Tunes the R35 GTR

Although we have been strongly focused on our Porsche development for the last couple of years, we recently took on an interesting project for a client of ours. The new Nissan R35 GTR. Having been tuning and modifying multivalve turbocharged engines now for many years, I have been involved in many projects spanning many platforms. One car that I have always been a fan of has been the Nissan Skyline. When we were approached about what we could do to enhance the GTR I was reluctant to get involved at first. However there was an interest in the back of my mind to see what we could do with the platform.

After doing some initial research to get familiar with the newest platform, I was impressed with Nissan's application of certain technologies. One thing I was not impressed with was the amount of "fluff" parts I was seeing being distributed for the cars or the banzai-crank-the-boost with racegas tuning tactics that I was seeing. I knew that it was important to take a look at what the car was actually capable of and what was really going on within the platform as we tried to push it beyond factory performance limits. One thing that I have come to realize at this point after many dyno pulls and recalibrations for different hardware... Many of the cars out there are running on the very edge of their durability and their longevity will certainly be tested. The Nissan ECU is very dynamic in its control strategies and this is absolutely the only reason many of the modified GTR's out there are staying together (for now).

During the development of this GTR, we have done an enormous amount of data aquisition and testing. We were able to see the deficiencies of certain factory components and confirm the outstanding performance of others. I am steadfast in my stubborness in regard to not adding any component to a project that doesn't contribute to the end goal. Rather than just throwing parts at a given project to achieve a result, it's important to know why you are changing them.

Since our client was looking to road race his car heavily (yet wanted the ability and convenience of not having to find race gas all of the time to enjoy the car), I wanted to lay out a combination that would make around 700hp at the crank without stressing the engine or transmission. I also wanted the car to be ultra consistent. What good is 700hp if you can only use it once before you have to let the car cool completely down to get the same performance? Dyno Queen? No thank you. I don't race dyno sheets.

In order to generate this kind of performance reliably and consistently, it is imperative that you increase the efficiency of the combination. It was my personal opinion that to run the stock intercooling and turbochargers much beyond factory levels was pushing those components into areas of inefficiency that would eventually become counter productive to our efforts from a durability and performance standpoint. Data analysis from testing easily confirmed this.

Working with our development partners, we have been able to put together a combination with the finest turbocharger technology currently available. These new turbochargers utilize Garrett GT ball-bearing center sections and custom compressor wheels with the most applicable aero profile for this combination. These turbos not only produce the airflow needed to meet our performance targets, they also offer the best intial and transient boost response as well. This is hugely important for road course and street use. Along with the intercooler and plumbing package we have developed, this combination has the best thermal capacity we have produced on a platform to date. Our pressure drop through the entire system was less than .05 psi... virtually no pressure drop. While the cores can flow up to 1057hp worth of air, we are experiencing no loss in response from the combination. During our 4th gear runs on the dyno, our charge air temps would rise only 1 degree F max. Now that's efficiency!

The other key to success of this project has been in regard to tuning. Tuning is everything to a performance project like this. It is the key component to pulling everything together in order to achieve the desired result. We have been working with Cobb Tuning's Pro Tuner software with the GTR. As I prefer to do all of my own tuning on the packages we develop, ecu programming was essential to the success of the project... especially since we had to deal with huge increases in airflow which the standard calibrations are not compatible with.

At any rate, we've just completed our first round of testing on the new package and we were able to exceed our initial goals and projections along the way. Here's a quick video link showing our progress so far...

I am very happy so far with the performance, although we still have fine tuning to do. The transient response is outstanding and the driveability is that of a stock GTR at this point. I am looking forward to some road tuning and track time with the car in the very near future... we just need this damn snow to melt!

If you made it this far - thanks for reading!

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