D1SC efficency ?
06-22-2011, 01:34 AM
#2
The results I have a kind of weird. Here are some track results to compare:
Pullied to spin about 89% (very little belt slip) at the shift point it made 14psi and the truck ran 6.90's to 7.10's in the 1/8th at around 99-100 mph and 10.90's to 11.10's at around 124-126 mph in the 1/4.
Pullied to spin about 106% (no belt slip) at the shift point it made 23 psi and the truck ran 6.60's at 102 mph in the 1/8th and 10.40's at 126 mph in the 1/4. I should add here that this thing was a new animal at 23 psi. Procharger lag was a thing of the past, and felt like a rocketship.
Other than some minor AFR tune changes, a bigger fuel pump and colder plugs nothing else was different.
The IAT's tell part of the story, normally on low boost IAT's would drop about 20* below ambient and not really climb at all. On high boost the IAT's dropped about 5* below ambient at the beginning of the run and then climb about 20* by the end of the run. This shows some diminishing efficency but still nothing near out of control.
Now whats strange is the huge gain in et at all intervals on the track but no real gain in mph, which we usually associate with increases in HP. My conclusion is that there were two other limiting factors that prevented a gain in mph.
Factor one was my fuel system. IDC's on high boost with 60lb injectors where in the 137-139 range. My AFR was not dangerously lean (motor never got hurt and never pushed water at 23 psi), but it wasn't ideal for making the most HP with FI.
Factor two was my exhaust system. I was running 1 3/4" pacesetters y'd into a single 3" pipe for about 3-4 feet till it got to the 4" muffler. This was probably sufficient at 14 psi, but likely restrictive at the power potential of 23 psi. Based on a shitty dyno session and given the weight of the truck it was likely around 800 rwhp on 23 psi the way it was.
Talking to procharger really didn't help me much. At the time I was doing this I called them 3 different times and talked to 3 different techs. I asked them the same question "how fast can I spin this D1sc before it either falls off or explodes". I got 3 different answers. The first guy said not to spin past 64,000 (100%) as it will likely fail. The next guy said it would be a shot in the dark as he has seen D1sc impellers fail at 90% and some that lived till around 110%. The third guy said he has seen several racers spin them to 68,000 (106%) with no issues other than better et's and mph.
Now, I'm sure the D1sc could have been more efficient at 23 psi with a cam/heads change as well but that really just opens a whole new discussion.
So after all that reading, take it as you will. However, I pretty sure that as long as your blower and pulley/belt system is up to the task, you'll enjoy any increase up to the 106%that I was spinning. Providing you have the fuel quality and quantity available and a good tune up. I've always run C-16 in mine to be safe when I'm pushing for max power.
Pullied to spin about 89% (very little belt slip) at the shift point it made 14psi and the truck ran 6.90's to 7.10's in the 1/8th at around 99-100 mph and 10.90's to 11.10's at around 124-126 mph in the 1/4.
Pullied to spin about 106% (no belt slip) at the shift point it made 23 psi and the truck ran 6.60's at 102 mph in the 1/8th and 10.40's at 126 mph in the 1/4. I should add here that this thing was a new animal at 23 psi. Procharger lag was a thing of the past, and felt like a rocketship.
Other than some minor AFR tune changes, a bigger fuel pump and colder plugs nothing else was different.
The IAT's tell part of the story, normally on low boost IAT's would drop about 20* below ambient and not really climb at all. On high boost the IAT's dropped about 5* below ambient at the beginning of the run and then climb about 20* by the end of the run. This shows some diminishing efficency but still nothing near out of control.
Now whats strange is the huge gain in et at all intervals on the track but no real gain in mph, which we usually associate with increases in HP. My conclusion is that there were two other limiting factors that prevented a gain in mph.
Factor one was my fuel system. IDC's on high boost with 60lb injectors where in the 137-139 range. My AFR was not dangerously lean (motor never got hurt and never pushed water at 23 psi), but it wasn't ideal for making the most HP with FI.
Factor two was my exhaust system. I was running 1 3/4" pacesetters y'd into a single 3" pipe for about 3-4 feet till it got to the 4" muffler. This was probably sufficient at 14 psi, but likely restrictive at the power potential of 23 psi. Based on a shitty dyno session and given the weight of the truck it was likely around 800 rwhp on 23 psi the way it was.
Talking to procharger really didn't help me much. At the time I was doing this I called them 3 different times and talked to 3 different techs. I asked them the same question "how fast can I spin this D1sc before it either falls off or explodes". I got 3 different answers. The first guy said not to spin past 64,000 (100%) as it will likely fail. The next guy said it would be a shot in the dark as he has seen D1sc impellers fail at 90% and some that lived till around 110%. The third guy said he has seen several racers spin them to 68,000 (106%) with no issues other than better et's and mph.
Now, I'm sure the D1sc could have been more efficient at 23 psi with a cam/heads change as well but that really just opens a whole new discussion.
So after all that reading, take it as you will. However, I pretty sure that as long as your blower and pulley/belt system is up to the task, you'll enjoy any increase up to the 106%that I was spinning. Providing you have the fuel quality and quantity available and a good tune up. I've always run C-16 in mine to be safe when I'm pushing for max power.
06-22-2011, 07:20 AM
#3
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The results I have a kind of weird. Here are some track results to compare:
Pullied to spin about 89% (very little belt slip) at the shift point it made 14psi and the truck ran 6.90's to 7.10's in the 1/8th at around 99-100 mph and 10.90's to 11.10's at around 124-126 mph in the 1/4.
Pullied to spin about 106% (no belt slip) at the shift point it made 23 psi and the truck ran 6.60's at 102 mph in the 1/8th and 10.40's at 126 mph in the 1/4. I should add here that this thing was a new animal at 23 psi. Procharger lag was a thing of the past, and felt like a rocketship.
Other than some minor AFR tune changes, a bigger fuel pump and colder plugs nothing else was different.
The IAT's tell part of the story, normally on low boost IAT's would drop about 20* below ambient and not really climb at all. On high boost the IAT's dropped about 5* below ambient at the beginning of the run and then climb about 20* by the end of the run. This shows some diminishing efficency but still nothing near out of control.
Now whats strange is the huge gain in et at all intervals on the track but no real gain in mph, which we usually associate with increases in HP. My conclusion is that there were two other limiting factors that prevented a gain in mph.
Factor one was my fuel system. IDC's on high boost with 60lb injectors where in the 137-139 range. My AFR was not dangerously lean (motor never got hurt and never pushed water at 23 psi), but it wasn't ideal for making the most HP with FI.
Factor two was my exhaust system. I was running 1 3/4" pacesetters y'd into a single 3" pipe for about 3-4 feet till it got to the 4" muffler. This was probably sufficient at 14 psi, but likely restrictive at the power potential of 23 psi. Based on a shitty dyno session and given the weight of the truck it was likely around 800 rwhp on 23 psi the way it was.
Talking to procharger really didn't help me much. At the time I was doing this I called them 3 different times and talked to 3 different techs. I asked them the same question "how fast can I spin this D1sc before it either falls off or explodes". I got 3 different answers. The first guy said not to spin past 64,000 (100%) as it will likely fail. The next guy said it would be a shot in the dark as he has seen D1sc impellers fail at 90% and some that lived till around 110%. The third guy said he has seen several racers spin them to 68,000 (106%) with no issues other than better et's and mph.
Now, I'm sure the D1sc could have been more efficient at 23 psi with a cam/heads change as well but that really just opens a whole new discussion.
So after all that reading, take it as you will. However, I pretty sure that as long as your blower and pulley/belt system is up to the task, you'll enjoy any increase up to the 106%that I was spinning. Providing you have the fuel quality and quantity available and a good tune up. I've always run C-16 in mine to be safe when I'm pushing for max power.
Pullied to spin about 89% (very little belt slip) at the shift point it made 14psi and the truck ran 6.90's to 7.10's in the 1/8th at around 99-100 mph and 10.90's to 11.10's at around 124-126 mph in the 1/4.
Pullied to spin about 106% (no belt slip) at the shift point it made 23 psi and the truck ran 6.60's at 102 mph in the 1/8th and 10.40's at 126 mph in the 1/4. I should add here that this thing was a new animal at 23 psi. Procharger lag was a thing of the past, and felt like a rocketship.
Other than some minor AFR tune changes, a bigger fuel pump and colder plugs nothing else was different.
The IAT's tell part of the story, normally on low boost IAT's would drop about 20* below ambient and not really climb at all. On high boost the IAT's dropped about 5* below ambient at the beginning of the run and then climb about 20* by the end of the run. This shows some diminishing efficency but still nothing near out of control.
Now whats strange is the huge gain in et at all intervals on the track but no real gain in mph, which we usually associate with increases in HP. My conclusion is that there were two other limiting factors that prevented a gain in mph.
Factor one was my fuel system. IDC's on high boost with 60lb injectors where in the 137-139 range. My AFR was not dangerously lean (motor never got hurt and never pushed water at 23 psi), but it wasn't ideal for making the most HP with FI.
Factor two was my exhaust system. I was running 1 3/4" pacesetters y'd into a single 3" pipe for about 3-4 feet till it got to the 4" muffler. This was probably sufficient at 14 psi, but likely restrictive at the power potential of 23 psi. Based on a shitty dyno session and given the weight of the truck it was likely around 800 rwhp on 23 psi the way it was.
Talking to procharger really didn't help me much. At the time I was doing this I called them 3 different times and talked to 3 different techs. I asked them the same question "how fast can I spin this D1sc before it either falls off or explodes". I got 3 different answers. The first guy said not to spin past 64,000 (100%) as it will likely fail. The next guy said it would be a shot in the dark as he has seen D1sc impellers fail at 90% and some that lived till around 110%. The third guy said he has seen several racers spin them to 68,000 (106%) with no issues other than better et's and mph.
Now, I'm sure the D1sc could have been more efficient at 23 psi with a cam/heads change as well but that really just opens a whole new discussion.
So after all that reading, take it as you will. However, I pretty sure that as long as your blower and pulley/belt system is up to the task, you'll enjoy any increase up to the 106%that I was spinning. Providing you have the fuel quality and quantity available and a good tune up. I've always run C-16 in mine to be safe when I'm pushing for max power.
Last edited by sureshot; 06-22-2011 at 08:55 AM.
06-23-2011, 11:50 AM
#7
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06-24-2011, 01:01 AM
#8
Doubt you could find that limit with a 6-rib belt.
The 8-rib setup I had was the ****. I had at least 15 runs and 10 dyno pulls on the same belt, no dust and data logs never showed any signs of slip spinning it 106%. I should have kept it for a different project instead of giving it away.
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