Advice for intake porting

[Strictly Attitude]

Ok this is a ITB efi intake a speedmaster downdraft for sbc I am planning on doing some port work and matching them to my afr 195 street heads. If you look at the pictures the upper hole by the throttle body is where the injector sits and the lower hole is for the MAP common plenum under the intake. I know there are allot of guys here who do port work and some have done Vizards seminars also so I am looking for some advise here. I do not have access to flow bench but can accurately measure the ports to duplicate them. I am not looking to do anything major here but would like to improve what I can and open to any methods to help me out. Not my first time doing port work but at much different stage in my life where I feel allot can be learned from experience. I am trying to learn more so if you take time to explain I really appreciate it.
Being an efi intake would I want to stay rough finished below the injector? I believe this to be true but need verification
I am running a ev6 ford racing 4 hole injector would that have any effect in porting? I might see if I can find a video of one spraying just for reference. I don't think it will show anything ground breaking though.
Should my concentration be on that curved area on the inside radius of the curve? That was where I thought would be the most effective but I am green here would placing a wire or rod through the injector hole give better reference to the injector flow. Any pics that will help you guys help me let me know. I am sure I am limited mostly by amount of material here to remove.

This is the intake gives good idea of port design will check metal thickness of ports after roving ITBs

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You can see where the fuel rail is and kid of get an idea of the injector angle into the port

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These are the ports I will try for better pics tonight

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[groberts101]

Maybe it's just the close up pictures perspective.. but gawd that looks like a stupid wide port to start out with.

The AFR 195's take a 2005 or 2006 gasket size? Have you sized up the gasket surfaces on this intake to make sure they fall within that ports existing gasket size?

Can't say I'm digging the cockamamie angle on such short runners but IMHO, you don't really have a lot to work with there on such a short port. I'd say KISS it. Gasket match it to your heads(keep it about .020" x .020" smaller to aid in placement/ avoiding slight mismatches).. clean up and rough the whole port out with 50 or 60 grit tootsie rolls, or as you mentioned above.. at least everything below the injector location. Be sure to check your gasket opening sizes before matching. Despite their price and popularity, some brands are all over the damned place in size AND location. All you end up doing is transferring those discrepancies into the manifold and heads port sizing and locations.

If you want to get more adventurous than that, you could whittle away a smaller amount on that short inside port wall to help bias some flow back towards the center of the cylinder. Treat it like a pushrod pinch that just needs to have the peak flattened and tapered off to aid flow on that inside wall of the port. Looks plenty big already so maybe just work on refining the shape more than anything.

PS. One last tip. Needlessly digging out and gasket matching the heads mating flange on the PR pinch side generally only makes the PR pinches level of protrusion that much more prominent. You cut the PR pinch down to improve cross sectional size restriction and then shape it as smoothly as possible to promote attachment, help keep speeds under control along the short wall going past the bulge. Opening the head port entry all the way to a bigger gasket just serves to enlarge the wall that the PR pinch presents to the gas flow.

[Strictly Attitude]

Maybe it's just the close up pictures perspective.. but gawd that looks like a stupid wide port to start out with.

The AFR 195's take a 2005 or 2006 gasket size? Have you sized up the gasket surfaces on this intake to make sure they fall within that ports existing gasket size?

Can't say I'm digging the cockamamie angle on such short runners but IMHO, you don't really have a lot to work with there on such a short port. I'd say KISS it. Gasket match it to your heads(keep it about .020" x .020" smaller to aid in placement/ avoiding slight mismatches).. clean up and rough the whole port out with 50 or 60 grit tootsie rolls, or as you mentioned above.. at least everything below the injector location. Be sure to check your gasket opening sizes before matching. Despite their price and popularity, some brands are all over the damned place in size AND location. All you end up doing is transferring those discrepancies into the manifold and heads port sizing and locations.

If you want to get more adventurous than that, you could whittle away a smaller amount on that short inside port wall to help bias some flow back towards the center of the cylinder. Treat it like a pushrod pinch that just needs to have the peak flattened and tapered off to aid flow on that inside wall of the port. Looks plenty big already so maybe just work on refining the shape more than anything.

Thank you I appreciate it I will take some measurements tonight on the intake runners. My heads are still on my old engine but they will be off soon felpro 1205 is the recommended intake gasket. That is my pretty much the plan at hand figured getting some insight on this could not hurt.

[Newold1]

Please take my thoughts and comments here with the idea first that I am not trying to find things to make you feel bad or worried about your choice for a ITB system for your SBC engine and heads. I will try to be constructive but there are a lot of problems and issues with the shape and configuration of that ITB system that are not ideal or very efficient in my experience.
these type of Weber/EFI ITB systems have been around for many years and depending on the actual ultimate build and use this system may perform well and as you hope. It's not an ideal SBC ITB EFI injection configuration. I will explain my thoughts here.

First, realize what you have here is an old Weber configuration base manifold coupled with some newer throttle body components that were made to adapt to that old Weber carburetor base manifold design for and ITB EFI intake system.
This is why it creates some issues right off the bat. The inlet entrances and the throttle plates and areas are not pointed in the direction of the head port and the runners below the throttle plates have to make some large direction changes in a very short length to even meet the head port at the junction of the manifold and head port. This is always not an ideal ITB configuration as these changes in direction will lose some efficiencies and performance potential.

Second, having the injector right up next to the throttle plate will impart some disruption of the injector spray pattern uniformity and will probably cause more wetting of the intake tract below the throttle plate possibly and most likely at idle and part throttle opening points. I realize this is the way the throttle bodies were designed and built and they have to be at an angle and entrance point that aligns with the solid fuel rail assemblies and the fuel rails also need to fit between the right and left banks of the throttle bodies.
If you port out the intake runners to straighten the path to the head intake port you would most likely need to remove to much material and the large change in port cross area change with respect to the area of the throttle plates will also create problems.

Just these three problem areas I see will never allow the best correction of the mechanical and dimensional issues. I also realize that depending on the actual use for this engine be it a race only or street & strip use and the nature of the build with respect to rpm ranges, camshaft profile, compression, fuel type and type of drive ability desired that these factors and the actual performance characteristic of your completed engine and its intended use may not be a big problem for its use. Not knowing all your other info means I am supposing on somethings.

It is as a lot of ITB EFI systems a very "Cool" looking system on an engine and it looks as though the parts and linkage systems are well designed and most likely work well mechanically. This older Weber ITB setup worked much better on a symmetrical spread port head like many were and still are used on Ford small and big block engines. On the Chevy SBC and BBC engines with the siamesed intake ports, getting the Weber dimension manifold ports to line up efficiently with the cylinder head is a problem and does create flow problems. Some of these issues and limiters can be modified or adjusted to lessen the possible negative effects and improve the final system.

I am not sure if you have already started port matching the base manifold but if you have then returning the the whole assembly is not an option and you will have to just carefully try to improve the manifold and make it run smoothly and well with your EFI ECM control and tuning.

Sorry for the critique and frankness of my input but this is a situation where I wish people like myself here on Speedtalk with some pretty good ITB EFI experience could have reviewed what you were planning to use before you made the selection.

I hope you don't get to upset with my thoughts and info here, I apologize if you take some offense but I am only trying to be informative and honest!

[KnightEngines]

I'm with him^

If it's just for looks on a street engine then yeah, go for it, pretty much anything you do is gonna improve on that clusterf*ck!

If you want it to actually go then ditch that lot & find yourself an old Hilborne/Kinsler mechanical injection setup & convert it to EFI - it will be light years ahead.

You can probably sell the 4x weber style throttle bodies etc to cover the cost of an old Hilborne/Kinsler setup.

Sorry for the bad news.

[Newold1]

Just to give some here an example of a good ITB intake system that is a very nice candidate for an easy electronic EFI changeover, look at the Hilborn unit on Ebay item # 282328529736.

It got a good size throttle bore, straight runners and various length tuned stacks are easily available. this particular piece is being offered at $850 or best offer and it would be very easy and simple to put together a nice set of fuel rails, injector bungs and injectors. The existing mechanical injection nozzles can be removed and those passages can be connected with simple hoses for the MAP system and a TPS is also an easy add to make a unit like this a fully EFI type manifold system.

Just thought I would give a good example of a great flowing ITB fuel injection system should be configured with EFI for a small block chevy.

[Strictly Attitude]

Please take my thoughts and comments here with the idea first that I am not trying to find things to make you feel bad or worried about your choice for a ITB system for your SBC engine and heads. I will try to be constructive but there are a lot of problems and issues with the shape and configuration of that ITB system that are not ideal or very efficient in my experience.
these type of Weber/EFI ITB systems have been around for many years and depending on the actual ultimate build and use this system may perform well and as you hope. It's not an ideal SBC ITB EFI injection configuration. I will explain my thoughts here.

First, realize what you have here is an old Weber configuration base manifold coupled with some newer throttle body components that were made to adapt to that old Weber carburetor base manifold design for and ITB EFI intake system.
This is why it creates some issues right off the bat. The inlet entrances and the throttle plates and areas are not pointed in the direction of the head port and the runners below the throttle plates have to make some large direction changes in a very short length to even meet the head port at the junction of the manifold and head port. This is always not an ideal ITB configuration as these changes in direction will lose some efficiencies and performance potential.

Second, having the injector right up next to the throttle plate will impart some disruption of the injector spray pattern uniformity and will probably cause more wetting of the intake tract below the throttle plate possibly and most likely at idle and part throttle opening points. I realize this is the way the throttle bodies were designed and built and they have to be at an angle and entrance point that aligns with the solid fuel rail assemblies and the fuel rails also need to fit between the right and left banks of the throttle bodies.
If you port out the intake runners to straighten the path to the head intake port you would most likely need to remove to much material and the large change in port cross area change with respect to the area of the throttle plates will also create problems.

Just these three problem areas I see will never allow the best correction of the mechanical and dimensional issues. I also realize that depending on the actual use for this engine be it a race only or street & strip use and the nature of the build with respect to rpm ranges, camshaft profile, compression, fuel type and type of drive ability desired that these factors and the actual performance characteristic of your completed engine and its intended use may not be a big problem for its use. Not knowing all your other info means I am supposing on somethings.

It is as a lot of ITB EFI systems a very "Cool" looking system on an engine and it looks as though the parts and linkage systems are well designed and most likely work well mechanically. This older Weber ITB setup worked much better on a symmetrical spread port head like many were and still are used on Ford small and big block engines. On the Chevy SBC and BBC engines with the siamesed intake ports, getting the Weber dimension manifold ports to line up efficiently with the cylinder head is a problem and does create flow problems. Some of these issues and limiters can be modified or adjusted to lessen the possible negative effects and improve the final system.

I am not sure if you have already started port matching the base manifold but if you have then returning the the whole assembly is not an option and you will have to just carefully try to improve the manifold and make it run smoothly and well with your EFI ECM control and tuning.

Sorry for the critique and frankness of my input but this is a situation where I wish people like myself here on Speedtalk with some pretty good ITB EFI experience could have reviewed what you were planning to use before you made the selection.

I hope you don't get to upset with my thoughts and info here, I apologize if you take some offense but I am only trying to be informative and honest!

Thank you no feelings hurt here. Definitely saddened by this as there is not much room for any real porting.

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[groberts101]

these guys make valid points but another thing to keep in mind here is that a well calibrated/superior tuned lessor parts EFI/spark controlled combo can still often outrun an average tuned greater quality parts combo. Happens all the time on the street and the racetrack. People follow some good recipe's but then they screw up on adjusting the oven temperature.

If your main reason for choosing this manifold was bling factor then I'd say do what you can with porting and then put a big'ish cam and shorter rear gear that better matches the runner length in the thing and go have some fun. I'd lay cash that it won't be slow.

PS. I'd hunt down some taller stacks for that if you can squeeze them under the hood. That would most definitely help mitigate some of the injector location issues Newold mentioned above and the longer total runner length gives a wider overall powerband. One of the best things about stacks is their length tuning capability to better match the powerband/application.

[wyrmrider]

Yes they indeed do
we'd take the stacks off the Hillborns on a greasy track
had several sets for sticky tracks

[JoePorting]

The ports look pretty good as is. I'd just leave it as is. Maybe just knock off some obvious high casting points.

[Strictly Attitude]

these guys make valid points but another thing to keep in mind here is that a well calibrated/superior tuned lessor parts EFI/spark controlled combo can still often outrun an average tuned greater quality parts combo. Happens all the time on the street and the racetrack. People follow some good recipe's but then they screw up on adjusting the oven temperature.

If your main reason for choosing this manifold was bling factor then I'd say do what you can with porting and then put a big'ish cam and shorter rear gear that better matches the runner length in the thing and go have some fun. I'd lay cash that it won't be slow.

PS. I'd hunt down some taller stacks for that if you can squeeze them under the hood. That would most definitely help mitigate some of the injector location issues Newold mentioned above and the longer total runner length gives a wider overall powerband. One of the best things about stacks is their length tuning capability to better match the powerband/application.

The initial purpose was performance as it was a toss up between this and a stealth ram. The overall use of the car will be road race tracks such as lime rock or NY safety track and street usage realisticly mostly on the street but trying to maximize track performance at the same time definitely a compromise car.