Tractorsport Flowbench Forum Archive

by **Moparsled** » Thu Oct 16, 2008 1:34 am

I'm brand new here, and thought this would be a great place for my first post.
This is the engine for my current project, a vintage gas rail dragster. It's a 1950 Dodge 230 c.i. flathead six. Finned aluminum 9.75 to 1 head, Edmunds dual intake with two 1948 Plymouth carbs, A Mallory Magspark ignition, and a homemade header. (plus lots of other stuff)
I have been wanting to learn about and try flowbenching and porting for a while, so when the dyno runs put up numbers shy of my goals, I found this place.
Stock it was rated at 103 h.p. @3600 rpm
Currently it turns 171.5 @ 4250, runs out of steam at about 5100.
My goals were 200 horsepower and 6000 rpm redline.

we're going to find out what a properly designed and flowed system will do to get me to those goal #'s

by **bruce** » Thu Oct 16, 2008 6:25 am

Welcome to the forum!

Gotta love those flatheads!!

by **MrHijet** » Thu Oct 16, 2008 10:29 am

For me as a european that a 3.8 liter straight 6 engine ? Sounds great!

Welcome to the forum,

Daniel

by **Moparsled** » Thu Oct 16, 2008 10:42 am

by **106-1194218389** » Thu Oct 16, 2008 10:47 am

I love old iron. Nice job on yours. I have a 261 Chevy as one of my projects. Same as a 235 only bigger bore. I think a flathead is more challenging and I admire you flathead guys. You'll get your 200 hp.

John

by **106-1194218389** » Thu Oct 16, 2008 8:19 pm

I went and watched your videos. All I can say is WICKED! Are you sure you did not dub in a Cosworth F1 engine sound

I cannot believe a flathead six can sound so darn good. You have the tune pretty close. I notice you have all 6 primaries into one collector, correct? I want to do that with my 6 but I only have four primaries to worry about as the two center exhaust are siamese ports. Any way it really sounds good. Did you calculate out you collector configuration mathematically? Anyway nice job! btw for anybody needing exhaust parts here seems to be a very good place. Take a look at their merge collector kits

John

by **Moparsled** » Thu Oct 16, 2008 11:50 pm

the exhaust was a blast to build, unfortunately all the measurements were picked arbitrarily. I jumped into building it before doing thorough research, and know now where I messed up. A new header of similar design will be in the works later.

It is 6-2-1 design, each primary is 36" long, divided into two sets of three. Each three is by firing order.. 153 and 624. Each pipe is two inches behind the previous in each set, like a stair step. then the two pairs merge into one.

by **106-1194218389** » Fri Oct 17, 2008 4:28 pm

Do you have Pipemax? That is a great program for figuring out what you need. It will tell you the CSA for the ports you need, intake tract length and header makeup. Is very accurate and since you have dyno data will be wonderful for you. Larry Meaux is a great guy and very knowledgable. It is his software and here is his website

John

by **Moparsled** » Fri Oct 17, 2008 11:30 pm

Thanks for the link! That's now on my list as a must get.
Dumb question- what's CSA?

by **106-1194218389** » Sat Oct 18, 2008 12:22 am

by **106-1194218389** » Sat Oct 18, 2008 12:43 am

If you wanted to give me the following specs: and also a print out of your dyno sheets I will run the calculations for you;

John

by **WPH** » Sat Oct 18, 2008 11:30 am

Would you like to make a test run on my engine combo? I'd like to see what Pipemax suggests for my exhaust. I have a recent dyno run of my engine + some sim runs on data based on it. I might have an exhaust related issue and it would be great to compare two different approaches on a same subject.

by **106-1194218389** » Sat Oct 18, 2008 1:51 pm

sure, I'll help anybody here. You guys have helped me so much it is unbelievable what I have accomplished in such a short time. I am leaving town for the day but should be back later this evening.

John

by **WPH** » Sat Oct 18, 2008 2:18 pm

bore 3.346"
stroke 3.465"
rod length C-C 5.7"
#cyl inline 4
peak hp rpm 7420
CR 13:1

intake valve dia 1.299", 2/cyl
stem dia 0.236"
valve lift 0.472"
[email]duration@0.050[/email]" 239deg
CL 106deg
LCA 106deg

exhaust valve dia 1.142", 2/cyl
stem dia 0.236"
valve lift 0.416"
[email]duration@0.050[/email]" 246deg
exhaust centetline length 3.543"

VE@peak torque 114%, @peak HP 111% (taken from matching sim run)

I'm intrested in collector and primary tube lenghts + all the data. It would be great to share all of it with anyone intrested. I'll try to get dyno prints scanned so that I can upload them. I wish I had saved all flow data from this head but I'll try to fill in any info needed to get this engine combo in " bits & pieces "

by **106-1194218389** » Sat Oct 18, 2008 11:02 pm

I'll put the header stuff first as that is what you want the most, WPH. Also on the other pages that show the CSA I hope Larry Meaux or Larry Cavanaugh weighs in on this as they have more experience on the 4 valve stuff. I know the 4 valve can use a CSA that shows a much higher FPS than our normal 2 valve heads:

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