The merit in evaluating reverse flow at overlap-range lifts is clear, but what purpose is served by doing so at more than say 0.250"?
Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
This was suggested by more than one pro in past threads. I was actually expecting this port to flow much more in reverse than it did. Thanks, Charlie
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
I can't really pin point it Bill because I no longer have the flow sheets I had when testing (should have kept them when I sold the bench) but it seems to me that any time I lowered reverse flow anywhere in the curve, even if it lost flow the port was always more stable.
I wish I had spent more time developing why it was, but I knew it made more HP, and at that time that was all that concerned me.
Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Interesting, and non-intuitive...
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Dart 215 tech sheet.
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Been thinking of polishing out the radius under the 45 seat. Input welcome. Thanks, Charlie
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
MadBill got me thinking... Would a reverse flow, cfm - port energy curve be worth a look? I am thinking it could be a real help. Not sure if it has been done before. If there is some interest I will get it done this weekend. Thanks, Charlie
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Hi again, Charlie. Don't have much input on the flow and physics related to the task at hand here.. but I did want to take the time to commend you on your much improved porting quality as of late. That old saying "practice makes perfect" seems to be very true when it comes to shaping and carving metal.
I remember thinking the first set of heads I had done "professionally" looked downright horrible as if they'd been done by a blind man missing a few fingers but just passed it off as shape and size being the most important anyways. That.. and the price(GULP).. are what made me start doing my own from there onwards. Surprising how a few extra preloaded grinders or bit changes and another 30 minutes per set usually achieves that last bit of quality. Good looking stuff coming off your bench lately.
I remember thinking the first set of heads I had done "professionally" looked downright horrible as if they'd been done by a blind man missing a few fingers but just passed it off as shape and size being the most important anyways. That.. and the price(GULP).. are what made me start doing my own from there onwards. Surprising how a few extra preloaded grinders or bit changes and another 30 minutes per set usually achieves that last bit of quality. Good looking stuff coming off your bench lately.
Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Thanks! I would like to add, these are just pics from development. I spent zero time finessing these to make them pretty.groberts101 wrote: ↑Sat Mar 17, 2018 12:15 pm Hi again, Charlie. Don't have much input on the flow and physics related to the task at hand here.. but I did want to take the time to commend you on your much improved porting quality as of late. That old saying "practice makes perfect" seems to be very true when it comes to shaping and carving metal.
I remember thinking the first set of heads I had done "professionally" looked downright horrible as if they'd been done by a blind man missing a few fingers but just passed it off as shape and size being the most important anyways. That.. and the price(GULP).. are what made me start doing my own from there onwards. Surprising how a few extra preloaded grinders or bit changes and another 30 minutes per set usually achieves that last bit of quality. Good looking stuff coming off your bench lately.
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Roughing a fresh intake and the weapon of choice, Buckeye carbide 1/2" oval 45 degree helix. I bought this one at PRI, I also bought a 5/8" but it is just savage. This is a good mix of fast metal removal and a usable rough surface texture. Thanks, Charlie
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
You can only learn so much chasing cfm or port energy around on a flow bench. At some point you need other data, like dyno and/or track info. And it's likely you have figured out the shapes that flow good.
And I also think your grinding skills are good.
I just dynoed a 468 cube BBC with a set of 781 casting heads I did some porting on. The math on the csa says it'd peak at 6800-7000 but it was way short on cfm when figuring cfm demand for that cube/rpm. But it peaked right in that rpm range.
CFM only tells you so much.
Randy
And I also think your grinding skills are good.
I just dynoed a 468 cube BBC with a set of 781 casting heads I did some porting on. The math on the csa says it'd peak at 6800-7000 but it was way short on cfm when figuring cfm demand for that cube/rpm. But it peaked right in that rpm range.
CFM only tells you so much.
Randy
Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
My .02 is min CSA does NOT set the peak RPM.
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
I was taught early on, as a child, that practice doesn't make perfect. Practice makes permanent, and not from personal experience. If you're not doing it right to begin with, how do you perfect it? If you're practicing the wrong way/thing or your methods are flawed, you're not going to get perfect no matter how much you practice. Not saying this is the case currently. Just that I don't use that saying anymore and when I hear it, it makes one wonder just exactly how and what they're practicing. It might not be perfect, but it'll be permanent whether right or wrong.groberts101 wrote: ↑Sat Mar 17, 2018 12:15 pm Hi again, Charlie. Don't have much input on the flow and physics related to the task at hand here.. but I did want to take the time to commend you on your much improved porting quality as of late. That old saying "practice makes perfect" seems to be very true when it comes to shaping and carving metal.
I remember thinking the first set of heads I had done "professionally" looked downright horrible as if they'd been done by a blind man missing a few fingers but just passed it off as shape and size being the most important anyways. That.. and the price(GULP).. are what made me start doing my own from there onwards. Surprising how a few extra preloaded grinders or bit changes and another 30 minutes per set usually achieves that last bit of quality. Good looking stuff coming off your bench lately.
JC -
bigjoe1 wrote:By the way, I had a long talk with Harold(Brookshire) last year at the PRI show. We met at the airport and he told me everything he knew about everything.It was a nice visit. JOE SHERMAN RACING
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Randy,randy331 wrote: ↑Sat Mar 17, 2018 11:14 pm You can only learn so much chasing cfm or port energy around on a flow bench. At some point you need other data, like dyno and/or track info. And it's likely you have figured out the shapes that flow good.
And I also think your grinding skills are good.
I just dynoed a 468 cube BBC with a set of 781 casting heads I did some porting on. The math on the csa says it'd peak at 6800-7000 but it was way short on cfm when figuring cfm demand for that cube/rpm. But it peaked right in that rpm range.
CFM only tells you so much.
Randy
So just what CSA did you use?
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Re: Ported Dart 215 pro1 platinum with port energy discussion 2.0
Carnut1 wrote: ↑Sat Mar 17, 2018 11:50 amMadBill got me thinking... Would a reverse flow, cfm - port energy curve be worth a look? I am thinking it could be a real help. Not sure if it has been done before. If there is some interest I will get it done this weekend. Thanks, Charlie
Anything you can test, measure and quantify is worthy of doing. Like Randy said, you need to verify the end result with dyno and track results.
I used to say you can never have enough data, and most times that's true. There is a point where you end up in mental masturbation and overload.