Road Draft tube

jrvariel48

jrvariel48

Well-known member
I’m looking for suggestions for my blown motor as far as the road draft goes. How hot does that get? I’m having trouble with the routing because of the blower crank pulley & belt interference. Will a rubber hose stand the temperature? Not sure about the pcv thing. I had it on the the last blown motor because of heavy blow by but I’m hoping not to have that problem with a new motor
I’m all ears!
 
You can get rubber type tubing (not sure of the material) that will take just about any temperature you would see on an engine. We used a tube like that on 5.0 mustangs to connect the header pipes.

It was silicone tubing.
Silicone: 400 – 500°F (204 – 260°C)
 
Last edited:
JSeery said:
You can get rubber type tubing (not sure of the material) that will take just about any temperature you would see on an engine. We used a tube like that on 5.0 mustangs to connect the header pipes.

It was silicone tubing.
Silicone: 400 – 500°F (204 – 260°C)
Click to expand...

That's a great option JSeery, thank you!
 
Joe all engines have some amount of what we call blow by. There is some leakage from cylinder compression caused by the ring gaps and the other reason as the pistons come down in the cylinders they are moving as much cubic inches of air coming down as they do going up this explanation is a basic description of whats taking place. This air pressure caused when the pistons are coming down needs to go someplace so on older engines to vent this air pressure the road draft tube is used. And also the breather screen used on the oil fill cap. This also is main reason for the crankcase smell inside a car at times. On modern engines the crankcase pressure still exists but its no longer vented out of the engine by using the PCV the crankcase pressure is redirected and then consumed into the intake system. On your blower motor the crankcase pressure will be increased a lot when your running in a boost mode. Under normal driving conditions no boost the crankcase pressure will be similar to a normally aspirated engine with similar cubic inches. If it was my engine i would consider a PCV system.
Ronnieroadster
 
Ronnieroadster said:
Joe all engines have some amount of what we call blow by. There is some leakage from cylinder compression caused by the ring gaps and the other reason as the pistons come down in the cylinders they are moving as much cubic inches of air coming down as they do going up this explanation is a basic description of whats taking place. This air pressure caused when the pistons are coming down needs to go someplace so on older engines to vent this air pressure the road draft tube is used. And also the breather screen used on the oil fill cap. This also is main reason for the crankcase smell inside a car at times. On modern engines the crankcase pressure still exists but its no longer vented out of the engine by using the PCV the crankcase pressure is redirected and then consumed into the intake system. On your blower motor the crankcase pressure will be increased a lot when your running in a boost mode. Under normal driving conditions no boost the crankcase pressure will be similar to a normally aspirated engine with similar cubic inches. If it was my engine i would consider a PCV system.
Ronnieroadster
Click to expand...

Thanks Ronnie. I'm going back to the PCV set up I had on the last motor.
 
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