Teach me how to port a plenum
Thread Starter
Safety Car
Joined: Jul 2008
Posts: 3,966
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From: Made In America
St. Jude Donor '10-'11
Teach me how to port a plenum
I have a 1986 Early style Corvette. I just purchased a plenum from a 85 corvette. I am going to have one professionally ported by corvette plenum but am going to try to teach myself on the other plenum. What tools do I need and how do I go about doing it. Thanks in advance.
Former Vendor
Joined: Nov 2006
Posts: 2,482
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From: Carmichael ca
You need a diegrinder and an aluminum bit. At the front of the plenum, where the throttle body bolts on is where you can start. The floor of the plenum needs to be rounded out to match the TB. Be careful not to go to far and grind through. Otherwise grind the outlets to match the bigger runners.
Pro
Joined: Mar 2008
Posts: 702
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you need a a carbide burr set up for aluminum. Egg shape is most versatile. die grinder is a must or an electric equivalent. Use wax or some kinda of lubricant to metal from balling up. if the burr gets hot, cool it off with compressed air.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
I used all those tools. It'll look like you've been working in a silver mine when you're finished. Shavings everywhere; what a mess!!
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!
Tech Contributor
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From: Custer, WI
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Race Director
Joined: Jun 2004
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From: WI
The one I sold you is that big, I just didn't remove the center part. A 52 will fit it well and is what I had on it.
Tech Contributor
Joined: Oct 2008
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From: Custer, WI
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
Does wonders on stock engine; the EGR humps in the plenum floor behind the TB are a major flow restriction.One shown is taken out to suit 58mm but had no bad effects when run with stock 48mm TB.
Le Mans Master
Joined: Aug 2000
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From: Australia
Drifting
Joined: May 2006
Posts: 1,428
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From: Chewelah Wa
I scored meself a ported eddy tpi hi-flo last night on ebay for 275 bucks and free shipping. Now the search is on for a deal on some runners. I think I am somewhat partial to the SLP's. I have already done some porting on my plenum, but I am assuming that it will need to be siamesed for the SLP's? Are the SLP's and the ported Eddy a good combo or should I go with different runners? These items and some 1.6 rockers will be my next level of mods.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
How about this then
Some reading
http://forums.corvetteforum.com/c4-t...ock-350-a.html
http://www.thirdgen.org/siameseport
http://www.geocities.com/softtailduece01/
Some reading
http://forums.corvetteforum.com/c4-t...ock-350-a.html
http://www.thirdgen.org/siameseport
http://www.geocities.com/softtailduece01/
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
How about this then
Some reading
http://forums.corvetteforum.com/c4-t...ock-350-a.html
http://www.thirdgen.org/siameseport
http://www.geocities.com/softtailduece01/
Some reading
http://forums.corvetteforum.com/c4-t...ock-350-a.html
http://www.thirdgen.org/siameseport
http://www.geocities.com/softtailduece01/
This makes me want to break out the die grinder and start porting again..even though when I am porting I hate it.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
My '89 100K engine with siamized base like shown , the ported plenum in pic and stock SLP's ran 13.0X all day with a $100 take out ZZ4 cam and LT4 springs ($40)
Performance on a budget
A4 3.07
Thread Starter
Safety Car
Joined: Jul 2008
Posts: 3,966
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From: Made In America
St. Jude Donor '10-'11
Im going to keep the stock runners for awhile. Does anyone have a before/after pic of the front of the plenum? I just grind away the humps and thats it? Wow, seems easy just time consuming which I have plenty of.
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
When i did mine a few weeks ago I had the plenum done in just a few hours, granted i didnt do near that much porting to it as i'm still running the stock TB. I would upgrade runners while you are doing all this here is a comparison stock to ported edelbrock runners, which I have read are the smallest of the aftermarket ones. The porting is easy, just takes some patience and time, but I actually enjoyed it and am looking forward to porting the base out this weekend.
Burning Brakes
Joined: Oct 2009
Posts: 773
Likes: 2
From: Minneapolis MN
Put gaskets on part to be ported & take marker & mark where you can enlarge up to where gasket is(gasket porting?).Take small amounts off checking with gasket to make sure you do not go past gasket mounting surface.After porting use polishing bit to create smooth surface.Polish as far as you can to make smoothest surface for air to move.While part is off paint exterior of part.I recommend any color besides black because black attracts heat.I also heard of people painting underside of intake white because white reflects heat.I don't know if this is true & I would worry about paint coming off bottom of intake & getting in engine(oil).I would recommend having professionals do head work but,I would do my own intake & throttle body myself with above method.
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
While part is off paint exterior of part.I recommend any color besides black because black attracts heat.I also heard of people painting underside of intake white because white reflects heat.I don't know if this is true & I would worry about paint coming off bottom of intake & getting in engine(oil).