Question About a 2.38 Pulley
03-16-2018, 07:58 PM
#1
Race Director
Thread Starter
Question About a 2.38 Pulley
Correct me if I am wrong... but swapping out to a 2.38 pulley will spin the supercharger faster which will help increase boost / horsepower but... would that not also cause more heat causing the supercharger to heat-soak faster and go into limp mode sooner?
03-16-2018, 10:15 PM
#2
Pro
Yes, yes and yes. But a 2.38" is pretty mild, I want to say that's around 9% OD. You'd be able to safely run it on a Intake/Headers/Pulley setup. Toss in TR7IX plugs and an Expansion Tank for a little extra help. If you want more pulley, I'd highly recommend you run Meth injection or a flex fuel setup.
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Monkey D. Luffy (03-17-2018)
03-17-2018, 08:09 AM
#3
Race Director
Thread Starter
Yes, yes and yes. But a 2.38" is pretty mild, I want to say that's around 9% OD. You'd be able to safely run it on a Intake/Headers/Pulley setup. Toss in TR7IX plugs and an Expansion Tank for a little extra help. If you want more pulley, I'd highly recommend you run Meth injection or a flex fuel setup.
03-17-2018, 11:23 AM
#4
Drifting
With my upper/lower combo fuel was needed. I had a low side fuel setup by CPR installed, added E85 (for max HP when at the track) and meth for cooling and extra fuel at WOT. In the heat of AZ, I did a larger IC and an expansion tank just to preserve the extra HP gained from the mods. In high heat conditions I am 685hp/725tq at the wheels. I have never went into limp mode at the drag strip or 1/2 mile even with back to back runs.
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Monkey D. Luffy (03-18-2018)
03-17-2018, 12:06 PM
#5
Le Mans Master
Yes, more compression will make more heat, that's an unavoidable law of physics. But you also might be pushing the blower into regions where it's adiabatic efficiency is lower. In theory you could spin it harder and make less! I don't think that's the case here, though. You'll likely pick up some boost and the IAT2s will go up but overall you'll make more power.
Will that cause more heat soak? I don't know what "heat soak" even means to people but yes in theory, at least, there will be more heat to dissipate.
But limp mode has nothing to do with the supercharger, that's coolant temperature. Yes there are connections between the two but I'll treat them as separate.
So no, spinning the blower faster will not directly cause limp mode sooner.
- Dave
PS: I'm ignoring for now the possibility that more boost leads to more detonation and/or reduced timing which in turn causes higher engine temps due to the retarded timing, as I don't know if it's a material factor or not.
Last edited by davepl; 03-17-2018 at 12:09 PM.
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Monkey D. Luffy (03-18-2018)
03-17-2018, 01:15 PM
#6
Pro
You'd have to run CRAZY pulley combinations (We're talking a 2.1" upper with a 15% or 18% lower) for the LT4 to make less power with more overdrive. The 2.38" is not even close to that area. You won't need E85 or Meth with a 2.38" pulley. Like I said, Intake/Headers/Plugs/Expansion/2.38" is a nice 620+ RWHP setup. If you're going for more overdrive then you will need Meth or you'll be pulling timing like it's going out of style.
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Monkey D. Luffy (03-18-2018)
03-18-2018, 06:58 PM
#7
Race Director
Thread Starter
With my upper/lower combo fuel was needed. I had a low side fuel setup by CPR installed, added E85 (for max HP when at the track) and meth for cooling and extra fuel at WOT. In the heat of AZ, I did a larger IC and an expansion tank just to preserve the extra HP gained from the mods. In high heat conditions I am 685hp/725tq at the wheels. I have never went into limp mode at the drag strip or 1/2 mile even with back to back runs.
Yes, sort of, and No.
Yes, more compression will make more heat, that's an unavoidable law of physics. But you also might be pushing the blower into regions where it's adiabatic efficiency is lower. In theory you could spin it harder and make less! I don't think that's the case here, though. You'll likely pick up some boost and the IAT2s will go up but overall you'll make more power.
Will that cause more heat soak? I don't know what "heat soak" even means to people but yes in theory, at least, there will be more heat to dissipate.
But limp mode has nothing to do with the supercharger, that's coolant temperature. Yes there are connections between the two but I'll treat them as separate.
So no, spinning the blower faster will not directly cause limp mode sooner.
- Dave
PS: I'm ignoring for now the possibility that more boost leads to more detonation and/or reduced timing which in turn causes higher engine temps due to the retarded timing, as I don't know if it's a material factor or not.
Yes, more compression will make more heat, that's an unavoidable law of physics. But you also might be pushing the blower into regions where it's adiabatic efficiency is lower. In theory you could spin it harder and make less! I don't think that's the case here, though. You'll likely pick up some boost and the IAT2s will go up but overall you'll make more power.
Will that cause more heat soak? I don't know what "heat soak" even means to people but yes in theory, at least, there will be more heat to dissipate.
But limp mode has nothing to do with the supercharger, that's coolant temperature. Yes there are connections between the two but I'll treat them as separate.
So no, spinning the blower faster will not directly cause limp mode sooner.
- Dave
PS: I'm ignoring for now the possibility that more boost leads to more detonation and/or reduced timing which in turn causes higher engine temps due to the retarded timing, as I don't know if it's a material factor or not.
You'd have to run CRAZY pulley combinations (We're talking a 2.1" upper with a 15% or 18% lower) for the LT4 to make less power with more overdrive. The 2.38" is not even close to that area. You won't need E85 or Meth with a 2.38" pulley. Like I said, Intake/Headers/Plugs/Expansion/2.38" is a nice 620+ RWHP setup. If you're going for more overdrive then you will need Meth or you'll be pulling timing like it's going out of style.
Thanks for all the great information. I can always count on the guys from the forum to help answer questions. Thanks again!