Monday, July 28, 2014

Engine Mods

 I have been trying to purchase a VMax throttle body for my car most of the winter. Early in June I was finally able to get one. They are sold on an exchange basis and basically you end up paying $150.00 for a CNC ported throttle body. I would recommend this to anyone with a DBW throttle body just for the improved throttle response alone. If it added any horsepower as claimed I wont ever know as I never had my car baselined.

The installation was stupid simple and literally only took 15 minutes.

During "Black Friday" of 2013 I purchased some PFADT headers for the corvette, apparently just before they went out of business. They sat boxed in the garage until the beginning of June when Matty and I finally installed them.  I did not take any pictures of us installing them but I found a good shot of them on the internet. They are works of art, the guys that assembled these are real craftsmen.

The "tri-y" design of the headers promotes more torque than standard 4 into 1 headers with a small compromise in top end horsepower.

Here is a shot of the old manifolds and cats we removed, I am not sure of the weight savings I would guess it to be in the 20lb range.

After both the throttle body and headers were installed I drove the car for a few weeks. The car was much louder, there were no CELs but it seemed to me to be running very rich. This didn't make any sense to me as all the modifications should have made it run more lean. I was able to make an appointment on July 7th to have it tuned at Mike Norris Motorsports.

On its first dyno pull I was expecting to see around 390hp, so I was less than happy to see it register 330hp. Mike got out of the car, stared at the screen for a few seconds and said "I am going to be a hero today". I did not understand right away what he meant because I was so focused on the HP figure I did not see the air/fuel ratio.

If you look at the dyno sheet the air/fuel spikes at 2200 and goes off the chart at 3200rpm.

After 20 minutes on the laptop Mike made the second pull which netted 413hp 410tq. He said he wanted to lean it just a bit more and on the third pull it made 415hp 414tq.

Here is a video Matty took of the third dyno pull:

Two days after the session I took it back to ORP, my previous best run was a 12.7@113 with a 1.9 60 foot, this improved to 12.2@117 with a 2.1 60 foot. I don't know if it was the extra power, my driving or track temp that slowed the 60 foot but with the current tires on the car launching it quickly is very difficult. I did not lower the pressures as I have in the past and that may have been the difference.

The car has a noticeable increase in power and sound. It currently has me satisfied but like any other mods it wont be long before the power level is comfortable and I will be looking for more.

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