Ported Lower Manifold

MethCobra

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I keep reading no gains in ported lower manifolds. What I am interested in is if there is a drop in boost at same power level. I hear 1- 1.5psi drop. Any truth to this.

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Posi

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Porting it does nothing and my own personal lower intake had 12 hours or so in it. We checked on dyno same day testing while the car stayed strapped down. Identical hp and tq as well as boost. It was like it hadn't been touched. Maxed out Race Ported Eaton for testing with 2.9/6lb combo. Also had a 3.4 Whipple customer that showed no gains as well.
 

GodStang

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It can actually be bad. We did porting on a lower. Dynoed the car. Pulled the lower while sitting on the dyno and put the new ported lower on and redynoed. Gained no hp and lost no boost. Same car, same dyno, same day, only change was a lower intake.

If you port match the lower intake to the gasket and DON'T have ported heads you have just put a decent size lip in air flow path that can/will cause turbulence and can actually make the flow worse.
 

CobraBob

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Porting it does nothing and my own personal lower intake had 12 hours or so in it. We checked on dyno same day testing while the car stayed strapped down. Identical hp and tq as well as boost. It was like it hadn't been touched. Maxed out Race Ported Eaton for testing with 2.9/6lb combo. Also had a 3.4 Whipple customer that showed no gains as well.

It can actually be bad. We did porting on a lower. Dynoed the car. Pulled the lower while sitting on the dyno and put the new ported lower on and redynoed. Gained no hp and lost no boost. Same car, same dyno, same day, only change was a lower intake.

If you port match the lower intake to the gasket and DON'T have ported heads you have just put a decent size lip in air flow path that can/will cause turbulence and can actually make the flow worse.

Pay attention to both Brian's post and Josh's. You've got your answer. Save your time and don't bother porting the lower. You're just going end up expending time with no positive results. Both of these guys know what they're talking about!
 

Posi

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I'll add my ported lower was gasket matched as well as the heads. Still nothing.
 

MethCobra

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Porting it does nothing and my own personal lower intake had 12 hours or so in it. We checked on dyno same day testing while the car stayed strapped down. Identical hp and tq as well as boost. It was like it hadn't been touched. Maxed out Race Ported Eaton for testing with 2.9/6lb combo. Also had a 3.4 Whipple customer that showed no gains as well.
Well then
Screenshot_20180206-225124.jpg


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wckdvnm

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Yeah quite confused as to what you are implying. It literally says no gains; I’ve looked at one myself and saw nothing restrictive about it.


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Posi

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I wonder if MethCobra knew he was quoting my dyno results lol. Yes it lost a pound of boost but we were on the dyno that morning then later that afternoon. Perfect explanation.
 

GodStang

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Yeah quite confused as to what you are implying. It literally says no gains; I’ve looked at one myself and saw nothing restrictive about it.


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Most of the time when porting an intake you are porting runners to open them up. This intake has no runners. It is just an open box. I would think the biggest restriction for the bigger blower guys would be the intercooler on the bottom of the blower.
 

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