intake manifold porting question.
02-08-2007, 02:27 PM
#1
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intake manifold porting question. I plan on changing the intake manifold gasket soon, so i figured while it was off of the car i would get it ported. Can anyone tell me if it would be worth it do to so?
02-08-2007, 05:49 PM
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DO NOT gasket match the intake. The floor and roof are fine at the gasket area. Just remove material from the divider wall between ports at gasket area and the outer walls just need to be straitened up if you have the intake that tapers smaller at the top. If your intake is pretty much strait on all walls, just leave it alone at the gasket area.
You wanna raise the roof of the intake just behind the inj and remove as much of that ski slope as you can.
You wanna have the port steadily get wider as it goes back to plenum area and have it end up about .100-.120 wider at the plenum area.
Lower the floor (NOT at gasket area) all the way to plenum and correct the angle that the ports on the intake and head match up. It is more of an L shape now and you need to straiten this out.
Open the TB holes up to 58 MM and grind down the IAC bump and make the TB holes go strait back by removing a lot of this hump. Then taper the bump smaller and round the bump off on the back side like an air plane wing. Remove a lot of material from the sides of the intake behind the TB holes and make it slowly taper to the rest of the intake. Make sure and look/feel on the outside of the intake and see where the thin spots are that will limit what you can do.
You wanna raise the roof of the intake just behind the inj and remove as much of that ski slope as you can.
You wanna have the port steadily get wider as it goes back to plenum area and have it end up about .100-.120 wider at the plenum area.
Lower the floor (NOT at gasket area) all the way to plenum and correct the angle that the ports on the intake and head match up. It is more of an L shape now and you need to straiten this out.
Open the TB holes up to 58 MM and grind down the IAC bump and make the TB holes go strait back by removing a lot of this hump. Then taper the bump smaller and round the bump off on the back side like an air plane wing. Remove a lot of material from the sides of the intake behind the TB holes and make it slowly taper to the rest of the intake. Make sure and look/feel on the outside of the intake and see where the thin spots are that will limit what you can do.
02-08-2007, 08:41 PM
#4
Originally Posted by the_merv
Why wouldn't you want to completely square off the Ports to the Gasket. I have done that, haven't had a problem. I also did the TB Ports, 58mm, and did the same with the IAC bump.
There is a big difference between
I have done that, haven't had a problem.
02-08-2007, 09:09 PM
#6
Originally Posted by 96capricemgr
There is a big difference between and it being worthwhile.
That many hours in front of a flowbench tends to teach you a thing or two
02-08-2007, 09:19 PM
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Originally Posted by James Montigny
Exactly; Lloyd knows what he's talking about.
That many hours in front of a flowbench tends to teach you a thing or two
That many hours in front of a flowbench tends to teach you a thing or two
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02-09-2007, 01:16 AM
#8
i cant see in no way, shape or form how or why you shouldnt gasket match it. Iv been thinkin all night and couldnt come up with any logicial reason. If you hafe a gasket sticking in a 1/4in. into the air stream, isnt that ****** up the air flow hardcore?! Dont you want it to flow in real good and smooth.
02-09-2007, 03:19 AM
#10
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Originally Posted by NightTrain66
grind down the IAC bump and make the TB holes go strait back by removing a lot of this hump. Then taper the bump smaller and round the bump off on the back side like an air plane wing. Remove a lot of material from the sides of the intake behind the TB holes and make it slowly taper to the rest of the intake. Make sure and look/feel on the outside of the intake and see where the thin spots are that will limit what you can do.
Pics?????????
02-09-2007, 03:34 AM
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Originally Posted by minesfaster
yeah i am curious about this as well. Does anyone have a diagram on where to port a SLP LS6 intake manifold ?
thanks
thanks
02-09-2007, 08:02 AM
#12
Originally Posted by Taubr Unit
i cant see in no way, shape or form how or why you shouldnt gasket match it. Iv been thinkin all night and couldnt come up with any logicial reason. If you hafe a gasket sticking in a 1/4in. into the air stream, isnt that ****** up the air flow hardcore?! Dont you want it to flow in real good and smooth.
If the gasket sticks into the port then yeah you have to deal with that but that is not what is being discussed here.
Another consideration is if you open the intake up to the gasket without doing the heads then the head ports will be smaller and you will have a big shelf in the airstream, BAD. If you do the heads and intake right too the gasket they probably do not line up perfect on reassembly and you get a big shelf.
02-09-2007, 08:46 AM
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The intake port of the heads should not be gasket matched either. You can match the roof, floor and center divider wall but the outer walls just need to be squared up and NOT layed back to the gasket.
Once you open up the push rod pich as far as you can, you want the outer wall to come strait back and keep the cross section as consistant as possible.
Laying the outer wall back to the gasket will do a 2 things . . . .
1 - Make the cross sectionsal areas at the PR pinch and gasket area have more of a variance causing more of a velocity change (faster at PR pinch and slower at gasket area) and hurting flow.
2 - Make the air have to see even more of a turn to go past PR pinch and hurt flow.
You want the gasket areas on the intake manifold and head to match but they do NOT need to match a gasket on the outer wall. If someone ported the heads and gasket matched them and they are all jacked up, I guess the damage is done and gasket matching the intake will not hurt any but if the heads were done correctly and NOT gasket matched, the intake doesn't need to be either.
When you measure in the intake, you will see the gasket area is pretty much the largest area and the last place to grind when trying to help flow. Measure every 1/2 inch or so up through the runner and you will see it gets smallest at the ski slope for the inj. THIS is the one area you want to grind on if you are only gonna grind on one area. Try and get the cross section at this point to match the cross section at the PR pinch and even bigger if possible. Once you have this measurement, try and keep the port the same cross section from there to the gasket area on the intake and from the gasket area to the PR pinch of the head. Once you understand this is what needs to be done, you realize opening the gasket area on the intake and head will make these areas bigger than the 2 restriction areas, you understand why it is wrong.
The gasket areas are NOT the restrictions and the PR pinch and ski slope of intake are.
Once you open up the push rod pich as far as you can, you want the outer wall to come strait back and keep the cross section as consistant as possible.
Laying the outer wall back to the gasket will do a 2 things . . . .
1 - Make the cross sectionsal areas at the PR pinch and gasket area have more of a variance causing more of a velocity change (faster at PR pinch and slower at gasket area) and hurting flow.
2 - Make the air have to see even more of a turn to go past PR pinch and hurt flow.
You want the gasket areas on the intake manifold and head to match but they do NOT need to match a gasket on the outer wall. If someone ported the heads and gasket matched them and they are all jacked up, I guess the damage is done and gasket matching the intake will not hurt any but if the heads were done correctly and NOT gasket matched, the intake doesn't need to be either.
When you measure in the intake, you will see the gasket area is pretty much the largest area and the last place to grind when trying to help flow. Measure every 1/2 inch or so up through the runner and you will see it gets smallest at the ski slope for the inj. THIS is the one area you want to grind on if you are only gonna grind on one area. Try and get the cross section at this point to match the cross section at the PR pinch and even bigger if possible. Once you have this measurement, try and keep the port the same cross section from there to the gasket area on the intake and from the gasket area to the PR pinch of the head. Once you understand this is what needs to be done, you realize opening the gasket area on the intake and head will make these areas bigger than the 2 restriction areas, you understand why it is wrong.
The gasket areas are NOT the restrictions and the PR pinch and ski slope of intake are.
02-09-2007, 09:38 AM
#16
Originally Posted by Taubr Unit
i cant see in no way, shape or form how or why you shouldnt gasket match it. Iv been thinkin all night and couldnt come up with any logicial reason. If you hafe a gasket sticking in a 1/4in. into the air stream, isnt that ****** up the air flow hardcore?! Dont you want it to flow in real good and smooth.
No offense, but that would be due to you not have years of porting experience. I don't understand when an expert tries to teach some you guys something they learned from years of experience you would try to argue. You should just be thankful he tried (In this case, maybe in vain.) to help you. This is not just another kid on some message board. Why not listen to the man? You just MIGHT go faster.
Good luck, Ed
02-09-2007, 10:54 AM
#17
I am listing ed. I know hes the man 100%. I was just saying that so someone can teach me. That is how you learn is by asking questions. Now, your saying NOT to actually take off meterial off the intake and heads correct? What if you leave the intake and heads alone and just grind the actual gasket away a little if its in the air stream. Im not one to just get a grinder and go to town, ill leave that to you guys but ill clean up the actual gasket if its interfering with airflow. This is fine right?
02-09-2007, 11:05 AM
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please do not gasket match it....its like saying fel pro or whomever knows what CSA is needed for your cylinder head and engine. You could either scribe off the gasket and use a bigger corner radius as long as its consistent throughout the port or just make your own port and order a blank 1290 felpro gasket and make your own
02-09-2007, 11:17 AM
#20
Well i dont know how the gasket lay in there and my heads are still stockers. Im just asking from experience from my iroc. The runner gaskets were garbage and had to fix them up a lot. But at the same time, someone could make a gasket a tad off and maby just a millimeter of the gasket is in the airstream. Most likely wont happend, but just throwin it out there.