Porting upper intake plenum
Thread Starter
6th Gear Member
Joined: Oct 2006
Posts: 10,551
From: Texas
Porting upper intake plenum
what do you need to do it? iv been thinking about swapping my 70mm accufab tb onto the stock plenum just becuase the pony is cool. if i could find a way to clean the pony up like new and maybe get the stock intake chromed or powdercoated gloss black, i think that would look neat.
so n e body got some knowlage on it?
i have heard you can do it with a dremel, but any advice would help.
thanks
so n e body got some knowlage on it?
i have heard you can do it with a dremel, but any advice would help.
thanks
2nd Gear Member
Joined: Mar 2007
Posts: 188
From: Washington
RE: Porting upper intake plenum
I would see if you can get a air tool with a good burr bit on it, then when you get down to the finish work use a less aggessive burr with the dremel. Sounds like fun though im sure if you mess up you can get one for next to nothin at a junkyard *plenum that is*. I would sand the out side of it off real good to get it smooth and then polish it, that would look sweet!
Thread Starter
6th Gear Member
Joined: Oct 2006
Posts: 10,551
From: Texas
RE: Porting upper intake plenum
ORIGINAL: ninelives19821
I would see if you can get a air tool with a good burr bit on it, then when you get down to the finish work use a less aggessive burr with the dremel. Sounds like fun though im sure if you mess up you can get one for next to nothin at a junkyard *plenum that is*. I would sand the out side of it off real good to get it smooth and then polish it, that would look sweet!
I would see if you can get a air tool with a good burr bit on it, then when you get down to the finish work use a less aggessive burr with the dremel. Sounds like fun though im sure if you mess up you can get one for next to nothin at a junkyard *plenum that is*. I would sand the out side of it off real good to get it smooth and then polish it, that would look sweet!
5th Gear Member
Joined: Apr 2006
Posts: 3,625
RE: Porting upper intake plenum
I polished up my old plenum and it gets spotted up by moisture and foggy after a few weeks. You have to keep up on it all the time. Not really worth it. I would just take some Caliper paint to it since that paint is high temp and has ceramic coating in it for easy cleaning. I love the stuff. As far as keeping it because it looks nice....ehhhh, you can get a C&L plenum for fairly cheap and the airflow is improved a bit more than the stocker unit. That inside bend is a killer and there's no way to fix it except swapping it out with a diff one.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
RE: Porting upper intake plenum
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align][/align]This isdue to their being 3/4" or so higher which allows better internal contour at the"bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
5th Gear Member
Joined: May 2007
Posts: 4,524
From: Smyrna, TN
RE: Porting upper intake plenum
just called my local engine builder yesterday about this it should cost 50-70 dollers to port match and fully smooth and polish the plenum. but mine is a professional products not stock..
97targa did you seal the newly polished plenum?????
97targa did you seal the newly polished plenum?????
Thread Starter
6th Gear Member
Joined: Oct 2006
Posts: 10,551
From: Texas
RE: Porting upper intake plenum
ORIGINAL: cliffyk
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align] [/align]This is due to their being 3/4" or so higher which allows better internal contour at the "bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align] [/align]This is due to their being 3/4" or so higher which allows better internal contour at the "bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
RE: Porting upper intake plenum
ORIGINAL: H0SS302
well what about an intake spacer. if i port match to my 70mm tb, wouldnt an intake spacer give it that extra room cliff?
ORIGINAL: cliffyk
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align][/align]This isdue to their being 3/4" or so higher which allows better internal contour at the"bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align][/align]This isdue to their being 3/4" or so higher which allows better internal contour at the"bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
Thread Starter
6th Gear Member
Joined: Oct 2006
Posts: 10,551
From: Texas
RE: Porting upper intake plenum
ORIGINAL: cliffyk
[/align] [/align]Not really as the sweep of OEM elbow is still going to be constrained by the physical size of the casting--this is why porting the stock plenum can't accomplish what an aftermarket unit can. The physically bigger dimensions of 3rd party castings provide internal space for a much larger and better flowing "elbow". [/align] [/align]If you study the flow data, and understand that the most air a 4.6L engine can possibly move at 6500 rpm is 528 cfm (that's at an unattainable 100% VE, at 90% VE [still arguably high for a 2V motor] 475 cfm is the max needed) then you can see that the OEM TB and plenum are OK up to 90% WOT or so.[/align] [/align]It's only that last 10% where there is any need for better flow. This is why just slapping a TB and plenum on the 4.6 2V does not create any miracles. It does make the immediate response better, and can with a good tune give you 10 to 15HP+ in the mid-range, however peak HP does not benefit a whole lot.[/align] [/align] [/align]I am curious as to why are you going through all of this instead of just buying an aftermarket plenum ($90 to $120 on eBay)? [/align] [/align]Is it just the pony or one of those "just to see if I can" sorts of thing (Lord knows I;ve done my share of those)?[/align] [/align] [/align] [/align]
ORIGINAL: H0SS302
well what about an intake spacer. if i port match to my 70mm tb, wouldnt an intake spacer give it that extra room cliff?
ORIGINAL: cliffyk
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align] [/align]This is due to their being 3/4" or so higher which allows better internal contour at the "bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
There's nothing you can do to a stock upper plenum to make it flow as well as an aftermarket unit. Here's accufab's flow data (1/2 way down the page for the new-edge), all the aftermarket units except C&L are 110+ cfm better.[/align] [/align]This is due to their being 3/4" or so higher which allows better internal contour at the "bend". The OEM plenum can be made marginally better by porting, however there's nothing that can be done to make it the same as even the worst of the aftermarket pieces.[/align]
my plans are to powdercoat the plenum gloss black, and have the pony plaque shining on top. if there is not real difference in throttle response i think the powdercoated black plenum would look good with the performance red stb i have. i keep my engine bay VERY clean, so all the hoses are shining black along with fuse box and radiator cover. even the bottom of my hood is pretty spotless.
it is the throttle body that yeilds the throttle response right, the plenum doesnt really do all that much correct?