Attention: TDR Forum Junkies A friend of mine has a very similar truck to mine. His is a '98 12V 4X4 short bed with an auto, where as mine is a long bed 5-speed. We have very similar mods, too. He has a slightly milder torque plate and runs a stock HX35 with a 16cm housing whereas I have the PDR HX40/16.
The big difference, as far as this post goes, is he runs the Scotty II and I have the aFe. Also, he has a front air dam made by Doug Hofeldt, who makes the Air Bulldog ram air hood. This air dam has an air intake right in the middle with a 4" flex line that my friend has plumbed into the bottom of his Scotty II's shroud. He has also cut the 4" hole into the cowling, but can block that off if the noise gets bothersome.
This afternoon we took his truck and my air filter, some duct tape, and an extra digital temp gauge out to a test hill for some test runs. This hill is a 7% grade of which the top 3/4 mile straightens out and makes for a good test runs. The summit is at 4224 feet. We are located in the hot (thought not too hot today) dry, southern Idaho lowlands (i. e. the edge of the desert!).
We made 4 test runs with his Scotty in various configurations. Then we did a final run with my aFe. No special configurations for that. It's just put in as-is.
The intake air temp listed was taken by mounting the probe in mid air stream between the air filter and the turbo inlet. The gauge was a digital multimeter with a temp probe.
In all cases, the runs and readings were done at 65 mph going up hill.
Here we go.
Run 1: Scotty II. Cowel air blocked, dam air blocked. Only fender air available.
Outside air temp during ascent: 81 to 84 degrees
Intake air temp: 89 to 91 degrees
EGT: 1000 degrees, even
Boost: 15 lbs
Run 2: Scotty II. Firewall open to cowel air, dam air blocked. Fender air avail.
Outside air temp during ascent: 81 to 83 degrees
Intake air temp: 88 to 89 degrees
EGT: 975 degress, plus
Boost: 14 lbs
Run 3: Scotty II. Cowel air blocked, but dam air hooked up. Fender air avail.
Outside air time during ascent: 81 to 83 degrees
Intake air temp: 88 to 90 degrees
EGT: 975 degrees, even
Boost: 15 lbs
Run 4: Scotty II. Firewall air open to cowel, air dam air hooked up. Fender air avail.
Outside air temp during ascent: 82 to 83 degrees
Intake air temp: 91 to 92 degrees
EGT: 975 to 1000 degrees
Boost: 14 to 15 lbs
Run 5: aFe Mega Cannon. Cowel air blocked. Air dam air tube tucked away. Fender air avail.
Outside air temp during ascent: 83 to 84 degrees
Intake air temp: 89 to 91 degrees
EGT: 1000 degrees, minus
Boost: 14 to 15 lbs
So, in this case, there is very little difference between the aFe and the Scotty II.
It was odd that adding the cowel air and/or the air dam air didn't make much difference to the Scotty, either. The best performance was with the Scotty getting its air from the air dam but not the cowel. But again, the differences were very small.
Take it for what it's worth. I think I'll keep my aFe and he'll keep his Scotty!
-Jay
The big difference, as far as this post goes, is he runs the Scotty II and I have the aFe. Also, he has a front air dam made by Doug Hofeldt, who makes the Air Bulldog ram air hood. This air dam has an air intake right in the middle with a 4" flex line that my friend has plumbed into the bottom of his Scotty II's shroud. He has also cut the 4" hole into the cowling, but can block that off if the noise gets bothersome.
This afternoon we took his truck and my air filter, some duct tape, and an extra digital temp gauge out to a test hill for some test runs. This hill is a 7% grade of which the top 3/4 mile straightens out and makes for a good test runs. The summit is at 4224 feet. We are located in the hot (thought not too hot today) dry, southern Idaho lowlands (i. e. the edge of the desert!).
We made 4 test runs with his Scotty in various configurations. Then we did a final run with my aFe. No special configurations for that. It's just put in as-is.
The intake air temp listed was taken by mounting the probe in mid air stream between the air filter and the turbo inlet. The gauge was a digital multimeter with a temp probe.
In all cases, the runs and readings were done at 65 mph going up hill.
Here we go.
Run 1: Scotty II. Cowel air blocked, dam air blocked. Only fender air available.
Outside air temp during ascent: 81 to 84 degrees
Intake air temp: 89 to 91 degrees
EGT: 1000 degrees, even
Boost: 15 lbs
Run 2: Scotty II. Firewall open to cowel air, dam air blocked. Fender air avail.
Outside air temp during ascent: 81 to 83 degrees
Intake air temp: 88 to 89 degrees
EGT: 975 degress, plus
Boost: 14 lbs
Run 3: Scotty II. Cowel air blocked, but dam air hooked up. Fender air avail.
Outside air time during ascent: 81 to 83 degrees
Intake air temp: 88 to 90 degrees
EGT: 975 degrees, even
Boost: 15 lbs
Run 4: Scotty II. Firewall air open to cowel, air dam air hooked up. Fender air avail.
Outside air temp during ascent: 82 to 83 degrees
Intake air temp: 91 to 92 degrees
EGT: 975 to 1000 degrees
Boost: 14 to 15 lbs
Run 5: aFe Mega Cannon. Cowel air blocked. Air dam air tube tucked away. Fender air avail.
Outside air temp during ascent: 83 to 84 degrees
Intake air temp: 89 to 91 degrees
EGT: 1000 degrees, minus
Boost: 14 to 15 lbs
So, in this case, there is very little difference between the aFe and the Scotty II.
It was odd that adding the cowel air and/or the air dam air didn't make much difference to the Scotty, either. The best performance was with the Scotty getting its air from the air dam but not the cowel. But again, the differences were very small.
Take it for what it's worth. I think I'll keep my aFe and he'll keep his Scotty!
-Jay
