Intake manifold to cylinder head?

art leong · 03-21-2011, 06:47 PM

I have a new intake manifold. That was ported a touch larger than the intake port of the head. About .060 is what it looks like (I can see right down the throttle body to the cylinder head). I have a head that is a bit bigger but the smaller head when tested made a lot more torque.
I know that if the manifold were smaller than the head it probably wouldn't matter. But I'm not sure having the manifold a bit bigger than the head will effect it. I wonder if this will cause turbulence? And cut down on the flow?

Jim Wahl · 03-21-2011, 06:50 PM

Adger? Hummmmm? Jim

art leong · 03-21-2011, 06:54 PM

Quote:

Originally Posted by Jim Wahl

Adger? Hummmmm? Jim

I tried giving him a call. Will try tomorrow.

Daran Summerton · 03-21-2011, 07:17 PM

Art, buddy of mine had a oval port 396. Of course no money for the right intake but he scraped up a used square port for 50$. Thing was a MONSTER after we did that. You can imagine the port difference.

Adger Smith · 03-21-2011, 09:20 PM

Art,
It depends.
call my cell # 903 824 4924
I didn't hear the shop phone but a couple of times today because I had the flow bench screaming almost all day. I'll be on and off of it all morning and then getting my Camaro's front end aligned after lunch. I was busting *** to make it to NP. Jeff and Jeff better be glad my chassis guy screwed up things. They might have had to deal with a red car in that CIC race. Of course the car would have been good, but the driver might have performed like a rookie. HA! It just wasn't meant to be for me to be there... there will be a next ime, I hope. Now I'm playing catch up at the shop. :~(

Alan Roehrich · 03-21-2011, 10:41 PM

Art, just epoxy the intake and port it back to the correct size. Or have it done.

Adger Smith · 03-21-2011, 11:55 PM

Art,
sorry I missed your call tonight. I was fooling around, getting my car ready to load.
as for the intake/ head deal.
I will assume you tested 2 different head/port size combinations with the same intake.
If you did that and one head made more torque than the other it is probably because the intake restricted the bigger cross sectional head. I have seen good heads be choked by an intake.
Untill proven wrong by testing I take the approach that it is better to have the smaller head and use an intake that has some taper or larger port size that will not make the head loose flow when testing with the intake installed.
If the velocity of the small port is right it might pull harder and accelerate quicker than the larger vol head with a non restrictive intake.
A small ledge at the head intake port junction can cause a slight tumble/waterfall effect in the head port. Sometimes this is good because it will help keep fuel in suspension with the air even though the tumbling air makes the port see it's self as a smaller cross sectional. Sometimes if the veolicity is real high it will not waterfall as good and will shear the fuel out of the air. You will see that by having poor combustion and needing a severe jet change.
Now, where is the mismatch?
The high flow area is usually at the top of the port. If you have a mismatch it is usually better to have it on the bottom of the porrt. Can you slot the mounting holes and move the intake to where you have less or no mismatch at the top? If you have a mismatch on the walls it is best to position the intake where the inside wall is mismatched and the outside wall is lined up. What Alan suggested is a good way to fix it. Just make the epoxy trasition go way back into the intake. This is like building taper. No abrupt cross sectional changes allowed!! You want to stay away from building a hook at the end of the intake runner. That is real bad for flow.
I think I would try to line it up on the small/High Tq head as good as possible and see if it helps. That way you are testing the intake, not the heads.
Call me tomorrow. I've got a couple of other ideas, but it's time to give the pillow my head...
Adger

Billy Nees · 03-22-2011, 07:24 AM

Umm, one more thing to point out, where are your injectors located in regards to the head/intake?

art leong · 03-22-2011, 09:36 AM

Here are a couple of pics I just took
injectors are near the stock location.

Here is a picture down the throttle body. It necks down at the head. It is hard to see but the head is about .060 up on the bottom. Of the last (number 4) cylinder. I slotted the manifold to get it as good as it is The other ports line up pretty good.
This head is slightly smaller than my other one but had a broader torque range on the chassis dyno.

Adger Smith · 03-22-2011, 11:12 AM

Art,
Enjoyed the conversation this morning. Hope it works well for you.
I still think it was a mistake to show Billy Nees those pictures with the NOS port showing.

03-21-2011, 06:47 PM	#1
art leong VIP Member Join Date: Dec 2001 Location: Richmond Hill, Georgia Posts: 2,003 Likes: 0 Liked 1 Time in 1 Post	Intake manifold to cylinder head? I have a new intake manifold. That was ported a touch larger than the intake port of the head. About .060 is what it looks like (I can see right down the throttle body to the cylinder head). I have a head that is a bit bigger but the smaller head when tested made a lot more torque. I know that if the manifold were smaller than the head it probably wouldn't matter. But I'm not sure having the manifold a bit bigger than the head will effect it. I wonder if this will cause turbulence? And cut down on the flow? __________________ Art Leong 2095 SS

03-21-2011, 06:50 PM	#2
Jim Wahl Veteran Member Join Date: Jan 2002 Location: Central Florida Posts: 5,843 Likes: 666 Liked 683 Times in 129 Posts	Re: Intake manifold to cylinder head? Adger? Hummmmm? Jim __________________ Jim Wahl....NHRA #2239 S/SS - IHRA # 8 Stock, D2 Stock Champion (forever I guess) 2019 Baby Gators Stock Champion 2009 D2 National Open Stock Champion 1981 D2 West Palm Beach LDRS SS Runner Up Past President, Southern Stock / Super Stock Association.

03-21-2011, 07:17 PM	#4
Daran Summerton Senior Member Join Date: Jun 2003 Location: Las Vegas nv Posts: 600 Likes: 18 Liked 66 Times in 37 Posts	Re: Intake manifold to cylinder head? Art, buddy of mine had a oval port 396. Of course no money for the right intake but he scraped up a used square port for 50$. Thing was a MONSTER after we did that. You can imagine the port difference. __________________ 72 cutlass

03-21-2011, 09:20 PM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Intake manifold to cylinder head? Art, It depends. call my cell # 903 824 4924 I didn't hear the shop phone but a couple of times today because I had the flow bench screaming almost all day. I'll be on and off of it all morning and then getting my Camaro's front end aligned after lunch. I was busting *** to make it to NP. Jeff and Jeff better be glad my chassis guy screwed up things. They might have had to deal with a red car in that CIC race. Of course the car would have been good, but the driver might have performed like a rookie. HA! It just wasn't meant to be for me to be there... there will be a next ime, I hope. Now I'm playing catch up at the shop. :~( __________________ Adger Smith (Former SS) Last edited by Adger Smith; 03-21-2011 at 09:21 PM. Reason: sp

03-21-2011, 10:41 PM	#6
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,097 Likes: 1,542 Liked 1,775 Times in 404 Posts	Re: Intake manifold to cylinder head? Art, just epoxy the intake and port it back to the correct size. Or have it done. __________________ Alan Roehrich 212A G/S

03-21-2011, 11:55 PM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Intake manifold to cylinder head? Art, sorry I missed your call tonight. I was fooling around, getting my car ready to load. as for the intake/ head deal. I will assume you tested 2 different head/port size combinations with the same intake. If you did that and one head made more torque than the other it is probably because the intake restricted the bigger cross sectional head. I have seen good heads be choked by an intake. Untill proven wrong by testing I take the approach that it is better to have the smaller head and use an intake that has some taper or larger port size that will not make the head loose flow when testing with the intake installed. If the velocity of the small port is right it might pull harder and accelerate quicker than the larger vol head with a non restrictive intake. A small ledge at the head intake port junction can cause a slight tumble/waterfall effect in the head port. Sometimes this is good because it will help keep fuel in suspension with the air even though the tumbling air makes the port see it's self as a smaller cross sectional. Sometimes if the veolicity is real high it will not waterfall as good and will shear the fuel out of the air. You will see that by having poor combustion and needing a severe jet change. Now, where is the mismatch? The high flow area is usually at the top of the port. If you have a mismatch it is usually better to have it on the bottom of the porrt. Can you slot the mounting holes and move the intake to where you have less or no mismatch at the top? If you have a mismatch on the walls it is best to position the intake where the inside wall is mismatched and the outside wall is lined up. What Alan suggested is a good way to fix it. Just make the epoxy trasition go way back into the intake. This is like building taper. No abrupt cross sectional changes allowed!! You want to stay away from building a hook at the end of the intake runner. That is real bad for flow. I think I would try to line it up on the small/High Tq head as good as possible and see if it helps. That way you are testing the intake, not the heads. Call me tomorrow. I've got a couple of other ideas, but it's time to give the pillow my head... Adger __________________ Adger Smith (Former SS) Last edited by Adger Smith; 03-22-2011 at 12:21 AM.

03-22-2011, 07:24 AM	#8
Billy Nees VIP Member Join Date: Oct 2002 Location: On a hilltop in Pa. Posts: 4,481 Likes: 3,581 Liked 7,657 Times in 1,726 Posts	Re: Intake manifold to cylinder head? Umm, one more thing to point out, where are your injectors located in regards to the head/intake? __________________ Billy Nees 1188 STK, SS I'm not spending 100K to win 2K

03-22-2011, 09:36 AM	#9
art leong VIP Member Join Date: Dec 2001 Location: Richmond Hill, Georgia Posts: 2,003 Likes: 0 Liked 1 Time in 1 Post	Re: Intake manifold to cylinder head? Here are a couple of pics I just took injectors are near the stock location. Here is a picture down the throttle body. It necks down at the head. It is hard to see but the head is about .060 up on the bottom. Of the last (number 4) cylinder. I slotted the manifold to get it as good as it is The other ports line up pretty good. This head is slightly smaller than my other one but had a broader torque range on the chassis dyno. __________________ Art Leong 2095 SS

03-22-2011, 11:12 AM	#10
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Intake manifold to cylinder head? Art, Enjoyed the conversation this morning. Hope it works well for you. I still think it was a mistake to show Billy Nees those pictures with the NOS port showing. __________________ Adger Smith (Former SS)