Justin@VMP
August 30th, 2007, 11:02 AM
I decided to do some additional testing with the stock airbox.
GT500s are very sensitive to heat and weather conditions, so each time I do testing a new "baseline" is done. In this case, the baseline is a performance tune and completely stock intake, gains are then compared from there.
I removed the bottom half of the stock airbox and used double sided tape to hold the stock air filter to the factory airbox "lid". The results were impressive, I saw a gain of 13RWHP. I then re-installed the factory airbox bottom, but cut a 3.5" hole in the front of it. I was still up 8-10rwhp over a totally stock air intake.
http://www.vmptuning.com/GT500/2stockboxmods.jpg
Stock filter stuck to stock lid, stock bottom removed:
http://www.vmptuning.com/GT500/2stocklidnobox.jpg
3.5" hole cut in front of stock box:
http://www.vmptuning.com/GT500/2stockboxhole.jpg
These two mods resulted in slightly more boost in the mid range, but not the same gain in boost that we normally see with an intake in the 6000-6500rpm range. This tells me that the filter and/or airbox lid becomes a restriction in that range. We know from testing intakes on the 05+ GT and V6 that the lid design is very inefficient, a round MAF housing with a cone filter does much better because air can be sucked from 360*, not just one side like the factory panel filter designs.
GT500s are very sensitive to heat and weather conditions, so each time I do testing a new "baseline" is done. In this case, the baseline is a performance tune and completely stock intake, gains are then compared from there.
I removed the bottom half of the stock airbox and used double sided tape to hold the stock air filter to the factory airbox "lid". The results were impressive, I saw a gain of 13RWHP. I then re-installed the factory airbox bottom, but cut a 3.5" hole in the front of it. I was still up 8-10rwhp over a totally stock air intake.
http://www.vmptuning.com/GT500/2stockboxmods.jpg
Stock filter stuck to stock lid, stock bottom removed:
http://www.vmptuning.com/GT500/2stocklidnobox.jpg
3.5" hole cut in front of stock box:
http://www.vmptuning.com/GT500/2stockboxhole.jpg
These two mods resulted in slightly more boost in the mid range, but not the same gain in boost that we normally see with an intake in the 6000-6500rpm range. This tells me that the filter and/or airbox lid becomes a restriction in that range. We know from testing intakes on the 05+ GT and V6 that the lid design is very inefficient, a round MAF housing with a cone filter does much better because air can be sucked from 360*, not just one side like the factory panel filter designs.