Drive pressure (to p&p yet or not)

cummin get it

cummin get it

coal train
Joined
Sep 13, 2009
Messages
1,267
Just curious at what boost and drive pressure would you pullers suggest it is worth the time and money to port and polish the head with a barrel time manifold? I'm still a vp truck with a s475 t4 1.0ar but I'm seeing 75psi of boost. I'm putting a drive pressure gauge on tonight and pulling Thursday night so I will have a drive pressure then. I'm guessing it's around 100psi or so. Thanks Leo.
 
From the standpoint of engine flow, tuning until you hit the best peak torque production. You could get by with port clean up, unless you want to fully port. Polishing has a minimal reduction in flow efficiency so if you just want to reduce carbon buildup, polish the exhaust tract of the head. Keep the induction roughened so you have adequate adhesion to the port surfaces (floor, roof, walls). I would say clean it up, make sure turbulence isn't hindering any areas and shape your valves or even change valve designs if you see possible gains in a different valve for your engine.

After you have your flow in and out happening efficiently, tune your boost levels.
 
Just ran it up and down the gravel road I live on and I got it up to about 65psi boost but the drive was also right there with it maybe 5 psi difference but I'm using a $6 gauge from the hardware store so I don't know how quick it responds or how accurate it is. I will check it Thursday night maybe try to get a video.
 
That's what I'm thinking I don't want over 50. Guess next season it's p&p time. Just pulled tonight got another second place.
 
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