dart 215 pro 1 platinum upgrade on 383 sbc

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Carnut1
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by Carnut1 »

Back about 2009 I did a flattop 355 for my brother's 4 speed box nova with a brand new set of 165 Darts. Basic porting before flowbench 286 comp hr nice full roller comp rockers hot street build. They probably flowed 240-245 cfm even with shim head gaskets the compression was a bit lower than I would have liked but sounded snotty enough that my brother's neighbor cam running across the street to see what was under the hood. He owns a 1200hp twin turbo 70 Camaro! The little 355 was a great performer in the box nova. I think it is awesome Tony offered to help. This will be a great project.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by Warp Speed »

Carnut1 wrote: Tue Apr 24, 2018 5:33 am
Warp Speed wrote: Tue Apr 24, 2018 5:21 am
cspeier wrote: Tue Apr 24, 2018 12:25 am I'll answer the question on cross section.

OP, set your bench at max lift. See how much air it's moving. Place your pitot dead center. It should read 300-310fps. If it doesn't open it up until it does. Run it.

I would also open the throat area. This will help slow the air into the chamber.
Why didn't you suggest this when Carnut posted his finned wonder and the speeds were over 400?
Still no cross section recommendation, just pitot tube measurements?
And this is all at 28" ? LOL
"Finned wonder" I do appreciate your sence of humor! So it is named! Fyi finned wonder IS a street head. It may not be perfect but it is my first Dart 215. It flows 315 @.7" and 215@.7" lift. They will be used on a 420 ish cube motor if I find a nice block but since I need to prove my work they may go on my 383. Max rpm is 7000rpm. Warp, do you really think the high ssr speed will hurt the performance even if floor flow looks sweet with a string? Thanks, Charlie
Don't take offense with the name, its just my sense of humor.
Might be ok if the architecture was different, and the port was more of a straight shot. Being what it is, I think it is probably too fast, and from the above comment, Chad would agree. But then again, I'm no cylinder head guy.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by WeingartnerRacing »

Get a good 2.08 valve job 5angle
Set throat at 91.5%
Bowl 102%
From the head bolt across should be 2.08 that’s right after apex of short side toward valve.
Short side from deck 1.0
Width at pinch should be 1.165
Blend all this.
If you do this you should get the closest cross sections. We can talk about ideal cross sections but you are still at the mercy of the casting.

If you port enough heads you really don’t need the flowbench unless it is a brand new architecture. You will already have what cross section areas do and flow in certain areas. After that it’s just different shapes and the dyno is the better tool. The dyno is also better at experimenting with slightly different areas in certain areas in the port and how it effects the power curve.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by user-17438 »

WeingartnerRacing wrote: Tue Apr 24, 2018 8:01 am Get a good 2.08 valve job 5angle
Set throat at 91.5%
Bowl 102%
From the head bolt across should be 2.08 that’s right after apex of short side toward valve.
Short side from deck 1.0
Width at pinch should be 1.165
Blend all this.
If you do this you should get the closest cross sections. We can talk about ideal cross sections but you are still at the mercy of the casting.

If you port enough heads you really don’t need the flowbench unless it is a brand new architecture. You will already have what cross section areas do and flow in certain areas. After that it’s just different shapes and the dyno is the better tool. The dyno is also better at experimenting with slightly different areas in certain areas in the port and how it effects the power curve.
Exactly. I agree with you, knight and the few others . A flow bench is a good tool for logging results. But it can fool you easily. Better than 90% of my heads never see a bench. If the customer wants it that's a different story. But my customers never second guess me. They hired me to port the heads because the see my results on their track. And when people ask them what the flow. The answer is. They flow what they flow.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by groberts101 »

Figured it was just a matter of time before the bs started flying again. Glad this finally came full circle and is heading back in a constructive direction for Steve's build. Along with the last few good rec's, I would also highly recommend upping compression to better fit with Eric's rec's above. I'd imagine that will also give Mike a bit more latitude in his cam design. IF of course.. fuel availability will allow.

To Steve's question regarding size over the short turn the inherent design flaw of the bent port dictates what's needed to keep the flow attached on a running engine. I personally like to go a little bigger, especially towards a wider floor, than most guys do over the short side because it's a known and problematic area to settle down and equalize on anything but the most elite or cnc type 23° stuff with non-oem port layouts. Generally just accepted as a necessary evil to fill in the short sides curtain area. I've paid good head porters to do single ports to copy off of in the past and I'm confident that Tony will get close enough to perfect for this application.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by Warp Speed »

Question for the pitot tube guys.
How much area does the pitot take up in the port?
How would this area effect the local velocities being measured?
I remember Chad stating he can compensate for it?
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by user-30257 »

Warp Speed wrote: Tue Apr 24, 2018 10:07 am Question for the pitot tube guys.
How much area does the pitot take up in the port?
How would this area effect the local velocities being measured?
I remember Chad stating he can compensate for it?
Ask Rick Touchette . :wink:
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by groberts101 »

Warp Speed wrote: Tue Apr 24, 2018 10:07 am Question for the pitot tube guys.
How much area does the pitot take up in the port?
How would this area effect the local velocities being measured?
I remember Chad stating he can compensate for it?
I'm surely not the guy you were asking but hell, I tend to try to answer questions above my pay grade anyways, so why stop now. :lol:

Here's what I found on old cast iron extremely cross section limited stuff years ago. The introduction of the pitot into an already too fast and nearly choked area is almost nearly the same as using a flow ball. For that very reason, and I think someone mentioned it here earlier too, I mocked up a meat injector with my magnahelic gauge to see what was going on without getting false reading created by the added turbulence. Even tried a basketball inflation needle soldered to that as well. Crude as hell.. but it actually worked for what it was considering my flow bench was set to only 10" on the manometer.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by Rick360 »

No engine RPM range was mentioned (maybe I missed it) so I don't know how you can know how to size the intake port.

I don't see how some arbitrary port velocity measured on a flowbench will get it right. It has to be related to the engine size and RPM range.

Rick
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by GARY C »

Warp Speed wrote: Tue Apr 24, 2018 5:11 am
GARY C wrote: Mon Apr 23, 2018 9:18 pm
Warp Speed wrote: Mon Apr 23, 2018 9:05 pm

Yep, if it wasn't for a flow bench and a pitot tube we would still be in the dark ages CFD wise! Lol
Try to paint it as you will, but the fact remains, a cylinder head can be developed without a pitot tube, and without a flow bench for that matter. You would be surprised at the amount of successful port designs that are in use today, that were never flowed by the original producer! FACT!

But enough mucking up the guys thread, I think better advise would have been some cross sectional recommendations for what he is trying to accomplish. Its not rocket science.......
JMO
I agree, what cross sectional recommendations would you suggest?
I wouldn't, I'm not a cylinder head guy! Lol
I would leave that to a guru such as yourself, what you say?
But I damn sure know enough about engine development to spot bs! 8)
I posted what I thought he should do early on in the thread.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by GARY C »

Rick360 wrote: Tue Apr 24, 2018 10:44 am No engine RPM range was mentioned (maybe I missed it) so I don't know how you can know how to size the intake port.

I don't see how some arbitrary port velocity measured on a flowbench will get it right. It has to be related to the engine size and RPM range.

Rick
His rpm post from page 2
gary,
this might sound strange but it ran its quickest going to 7500 on the shift and traps 6800
a set of 4.3:1 would help it trap at 7000
i know that is some rpm but it responded and i dont have the answer,
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by Rick360 »

GARY C wrote: Tue Apr 24, 2018 10:47 am
Rick360 wrote: Tue Apr 24, 2018 10:44 am No engine RPM range was mentioned (maybe I missed it) so I don't know how you can know how to size the intake port.

I don't see how some arbitrary port velocity measured on a flowbench will get it right. It has to be related to the engine size and RPM range.

Rick
His rpm post from page 2
gary,
this might sound strange but it ran its quickest going to 7500 on the shift and traps 6800
a set of 4.3:1 would help it trap at 7000
i know that is some rpm but it responded and i dont have the answer,
So what RPM range does he want it to run? What converter stall? What are the goals?

If the most power at any rpm is the goal and gearing and converter will be matched it'd be a different csa than for 7500 rpm shift or if he leaves gearing alone and trapping at 6800.

Also, if the converter isn't enough the optimum shift rpm normally goes up.

Rick
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by GARY C »

Rick360 wrote: Tue Apr 24, 2018 10:57 am
GARY C wrote: Tue Apr 24, 2018 10:47 am
Rick360 wrote: Tue Apr 24, 2018 10:44 am No engine RPM range was mentioned (maybe I missed it) so I don't know how you can know how to size the intake port.

I don't see how some arbitrary port velocity measured on a flowbench will get it right. It has to be related to the engine size and RPM range.

Rick
His rpm post from page 2
gary,
this might sound strange but it ran its quickest going to 7500 on the shift and traps 6800
a set of 4.3:1 would help it trap at 7000
i know that is some rpm but it responded and i dont have the answer,
So what RPM range does he want it to run? What converter stall? What are the goals?

If the most power at any rpm is the goal and gearing and converter will be matched it'd be a different csa than for 7500 rpm shift or if he leaves gearing alone and trapping at 6800.

Also, if the converter isn't enough the optimum shift rpm normally goes up.

Rick
He's currently running an 8" 5600 converter.. He wants to make the car faster like all racers :D
all that is in his OP and more detail of his parts on page 2.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by B Original »

groberts101 wrote: Tue Apr 24, 2018 9:50 am Figured it was just a matter of time before the bs started flying again. Glad this finally came full circle and is heading back in a constructive direction for Steve's build.
Yea yippee horahh this round is finally over!!!!
groberts101 wrote: Tue Apr 24, 2018 9:50 am Generally just accepted as a necessary evil to fill in the short sides curtain area.
Yes very correct but another thing to consider is that port bias directs the air on the long side turn to enter the cylinder wall side contributing to the swirl motion. If you take very much flow for the SSR you can slow down the swirl to the effect of disrupting the swirl motion. The key is moderation you should apply your efforts more toward the short side of the SSR.

Picture this approximately 75%+- of the charge enters by the intake valve between 10 o'clock and the 4 o'clock position from the perspective of spark plug at 12 O'clock. If you allow too much air to make a path through the center of the cylinder it will disrupt the swirl. Which is all important to maximize combustion efficiency and or flame kernel burn speed. Consider that the more burn or thermal heat expansion at or near TDC eaquals more torque captured.

A consideration needs to be given to port development that promotes swirl and the path the charge enters into the cylinder. The down side is too much swirl can potentially blow the flame out although it is difficult to do, this can happen in extreme cases.
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Re: dart 215 pro 1 platinum upgrade on 383 sbc

Post by user-30257 »

B Original wrote: Tue Apr 24, 2018 11:11 am
groberts101 wrote: Tue Apr 24, 2018 9:50 am Figured it was just a matter of time before the bs started flying again. Glad this finally came full circle and is heading back in a constructive direction for Steve's build.
Yea yippee horahh this round is finally over!!!!
groberts101 wrote: Tue Apr 24, 2018 9:50 am Generally just accepted as a necessary evil to fill in the short sides curtain area.
A consideration needs to be given to port development that promotes swirl and the path the charge enters into the cylinder. The down side is too much swirl can potentially blow the flame out although it is difficult to do, this can happen in extreme cases.
Too much swirl just impedes airflow. It backs it up.

Is it a coincidence you quote garbage101 often, and then leave 5 paragraph responses like him?
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