Ported Dart pro 1 pre platinum

[Carnut1]

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Stock exhaust bowl.

[Carnut1]

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Deep exhaust bowl cut. About 10 min.

[Carnut1]

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Deep bowl cut flows. Only increases at high lift.

[groberts101]

looks good so far, Charlie. I know you're probably in the thick of it but couple quick questions for you.

What size and shape burrs do you use around the valve guide roof area?

What valvejob is on both ports right now.. original factory profile?

And hard to tell.. did you set the throats final choke size already? Or you do the bulk of the bowl work first and then connect and blend the dots together once you do the final throat cut?

[Carnut1]

Valve job and throat size is what they came with, not much smaller than I want at this point. These where roughed out with a 1/2" single cut aluminum burr.

[Carnut1]

Oval burr, I usually do valve job and set throat and chamber shape first but I want to start figuring what work offers what gains or losses. Thanks, Charlie

[cgarb]

Carnut...thank you for doing these threads. Its nice to be able to see the thought process in developing a port. Wish I had the equipment to test and grind like that and get good measurable results. Beats porting and watching how water flows through the port.

[Carnut1]

Carnut...thank you for doing these threads. Its nice to be able to see the thought process in developing a port. Wish I had the equipment to test and grind like that and get good measurable results. Beats porting and watching how water flows through the port.

Glad you enjoy the threads and I hope they help. For many years I would guess, grind and bolt on. Then see if it "feels" faster. Thanks, Charlie

[mag2555]

Charlie One thing to keep in mind is that on any parallel valve wedge type head is that a good deal more Exh enters the bowl on a angle from the center of the chamber and makes a B line for the cylinder wall side of the bowl!

In regards to this to me it means the trough on that side of the bowl and roof needs to be deeper and wider in the guide area, it also means that in turn that half of the short turn left to right needs to be taller as does the roof on the rest of the way out the port.

Just look at your post from Tuesday the 11th at 6.32 pm and the large difference in velocity readings that you took on the floor.
The side of the port with the low velocity could be made into a tighter are to pick up that speed and your disturbance will be greatly reduced, or gone!

[Carnut1]

Charlie One thing to keep in mind is that on any parallel valve wedge type head is that a good deal more Exh enters the bowl on a angle from the center of the chamber and makes a B line for the cylinder wall side of the bowl!

In regards to this to me it means the trough on that side of the bowl and roof needs to be deeper and wider in the guide area, it also means that in turn that half of the short turn left to right needs to be taller as does the roof on the rest of the way out the port.

Just look at your post from Tuesday the 11th at 6.32 pm and the large difference in velocity readings that you took on the floor.
The side of the port with the low velocity could be made into a tighter are to pick up that speed and your disturbance will be greatly reduced, or gone!

Mag, I am with you on these points and agree. You can see I have port bias on the roof and the ssr. I may need to increase that bias to really make it work. Thanks, Charlie

[mag2555]

I am shotting more for crackle free flow then bigger high lift numbers with what I posted, just to make it clear.

[groberts101]

Charlie One thing to keep in mind is that on any parallel valve wedge type head is that a good deal more Exh enters the bowl on a angle from the center of the chamber and makes a B line for the cylinder wall side of the bowl!

In regards to this to me it means the trough on that side of the bowl and roof needs to be deeper and wider in the guide area, it also means that in turn that half of the short turn left to right needs to be taller as does the roof on the rest of the way out the port.

Just look at your post from Tuesday the 11th at 6.32 pm and the large difference in velocity readings that you took on the floor.
The side of the port with the low velocity could be made into a tighter are to pick up that speed and your disturbance will be greatly reduced, or gone!

Mag, I am with you on these points and agree. You can see I have port bias on the roof and the ssr. I may need to increase that bias to really make it work. Thanks, Charlie

The bolded area seems intuitive.. but I believe it's just the opposite to that, Mag. That's why Chad was trying to show him so many pic's of flatter overblown floors with tall'ish arch's or squash port designs. Wide and/or taller roofs reduce restriction/improve velocity and wide floors help the flow turn the corner fully attached. Hard to achieve bit if the material is there.. squashed ovals are badass design too.

Maybe they're out there.. but I have personally never, not once, seen or even read about a conventional type exhaust port like this having such high exit speed differentials that ended up having a "too wide SSR" or that needed to be "gathered up" and reduced. On the intake port entry?.. sure, if you pooched the floor width and blew the hell out of the SSR till you hit water, but never on the exhaust ports exit. 50% exit speed reductions on the floor are typically the result of a SSR inefficiency(think, heavily dropped floor 351C heads). The short side becomes dettached and flow gathers up heavily on the roofs exit and spills down the sides. Like a low pressure flow dam sitting right smack in the middle of the apex.. port's too short so flow can't gather back up in time.. kills the floors exit speed. If Charlie probes about halfway down the pipe extension he will see the flow gather back up on the floor and speeds will equalize. And if he starts probing over the apex?.. he will find the actual separation point and "see" what the gasses want him to do to help ease their battle around the turn.

Not trying to come off as argumentative.. only trying to toss in my dirty penny. Maybe ask Chad or some other smarter guys?.. but that result sure seems like classic SSR flow detachment and turbulence to my old ears. Where's DV at when you need him too?

[Carnut1]

I have not done any Pitot speeds with pipe attached. Interesting thoughts on ssr speeds and turbulence. I may need to put my AFR collection on the bench and see how they get it done. Thanks, Charlie

[JoePorting]

Valve job and throat size is what they came with, not much smaller than I want at this point. These where roughed out with a 1/2" single cut aluminum burr.

If you upgrade to a 5/8 single cut oval burr you'll be able to do better quality work at half the time.

[groberts101]

Valve job and throat size is what they came with, not much smaller than I want at this point. These where roughed out with a 1/2" single cut aluminum burr.

If you upgrade to a 5/8 single cut oval burr you'll be able to do better quality work at half the time.

That was why I asked earlier. I typically prefer a ball end cylinder style in 5/8" or even 3/4" for intake ports. The bigger diamter long shanks get pricy fast but they can save you tons of time and aid port to port consistency. Form your corners with those and it's almost like you ran a mill through it before digging into the rest of the port. They, bigger sizes, work really nice inside bigger pockets too.