Attention: TDR Forum Junkies 
After seeing all these posts about SPS 66 versus PS 62 versus HTB2 versus stock turbos I decided to compile all my dyno results with all the different turbos I've run to show the various spool up times from 100 HP to 350 HP. If I couldn't get to 350 HP I used 300 HP instead. The results are interesting, somewhat predictable, and certainly speak volumes.
In the following discussion, the fastest spool time I use is when the boxes are at 100% fueling, going from 100 to 350 HP unless otherwise noted. With this in mind...
The fastest spooling combo was the VA C3. 1 pressure box with 100 HP injectors, PDR cam, and HTB2 62/14 turbo. This combo beat the HTB2 62/12 turbo, stock cam, plus VA C3. 1 combo to 300 HP by 0. 6 seconds. This is a testament to how well suited the VA C3. 1 is for towing as well as how much an aftermarket cam helps in spool-up.
Not surprising, the slowest spooling combo was with the SPS 66 turbo/100 HP injectors/PDR cam/Edge Juice. However it was only 0. 3 seconds slower to 350 HP than the HTB2 62/14 turbo/100 HP injectors/Edge Juice. This 0. 3 seconds translates to 20 HP coming in 60 rpm later in the powerband based on data I posted previously here
The slowest spooling combo, in addition, was 0. 6 seconds slower than the VAC3. 1, 100 HP injectors, PDR cam, HTB2 62/14, but still appeared to be equal or better than the stock truck with HTB2 62/12 turbo performance on the 100-300 HP spool basis.
I know I'm just as guilty as the next guy stating that a turbo spools - "just like stock!". However, these numbers certainly tell us otherwise!
The following is the summary table - take the data and do what you want!
In the following discussion, the fastest spool time I use is when the boxes are at 100% fueling, going from 100 to 350 HP unless otherwise noted. With this in mind...
The fastest spooling combo was the VA C3. 1 pressure box with 100 HP injectors, PDR cam, and HTB2 62/14 turbo. This combo beat the HTB2 62/12 turbo, stock cam, plus VA C3. 1 combo to 300 HP by 0. 6 seconds. This is a testament to how well suited the VA C3. 1 is for towing as well as how much an aftermarket cam helps in spool-up.
Not surprising, the slowest spooling combo was with the SPS 66 turbo/100 HP injectors/PDR cam/Edge Juice. However it was only 0. 3 seconds slower to 350 HP than the HTB2 62/14 turbo/100 HP injectors/Edge Juice. This 0. 3 seconds translates to 20 HP coming in 60 rpm later in the powerband based on data I posted previously here
The slowest spooling combo, in addition, was 0. 6 seconds slower than the VAC3. 1, 100 HP injectors, PDR cam, HTB2 62/14, but still appeared to be equal or better than the stock truck with HTB2 62/12 turbo performance on the 100-300 HP spool basis.
I know I'm just as guilty as the next guy stating that a turbo spools - "just like stock!". However, these numbers certainly tell us otherwise!
The following is the summary table - take the data and do what you want!
