Ported Ford 289 heads with port energy discussion

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
hoffman900
Guru
Guru
Posts: 1085
Joined: Sat Feb 23, 2013 5:42 pm

Re: Ported Ford 289 heads with port energy discussion

Post by hoffman900 » Sun Sep 10, 2017 7:48 pm

MadBill wrote:I'm not advocating that approach, merely providing a numerical answer to your flow-based pipe size question: "So is a flow chasing 53cc 1.6" valved exhaust that flows 170 cfm oversized for a relatively high rpm 289? Flows about 190 cfm with a 1 5/8" pipe. Thanks, Charlie"

As per my previous response, I believe pipe size comes first. Theories on the subject have certainly evolved over the years. The factory race system (developed in the late forties/early fifties) for the Vincent 61 c.i. V-twins I raced in the sixties was a pair of 2" x 54" pipes and a number of 30.5" singles in the pre-war era ran dual pipes of ~ 1.5". #-o
This.

A friend of mine talked with his old, late friend Mark Donohue at length about the AMCs. They tried all sorts of sizes on primaries on the Javelin motors with no difference, so they used what was most easily available. We know WAAAYYY better now and engines of that size with similar power are running primaries two sizes smaller. This totally means the ports they were using back then were way too big.
-Bob

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Ported Ford 289 heads with port energy discussion

Post by MadBill » Sun Sep 10, 2017 9:51 pm

FWIW, with all else equal, if you input a higher V.E. into the PipeMax program it of course estimates more power but also suggests a slightly smaller pipe. :-k
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

randy331
Guru
Guru
Posts: 2542
Joined: Mon Dec 04, 2006 7:30 pm
Location: N.W. MO.

Re: Ported Ford 289 heads with port energy discussion

Post by randy331 » Sun Sep 10, 2017 10:00 pm

digger wrote:
MadBill wrote:Update:
I found a graph by David Vizard in his How to Build Horsepower book; it also can be seen about 1/4 of the way through his Max Small Block book as seen here: http://www.chevydiy.com/chevy-small-blo ... t-systems/

The chart suggests pipe size vs. exhaust flow. For a street/strip engine with 170 CFM flow, a pipe ID ~ 1.60" is shown.
that methodology for choosing pipe size would perpetuate the issues of an oversized port. i think pipe size has hardly anything to do with port flow on a flow bench.
I'd say optimum ex pipe size has nothing to do to do with what the ex port flowz on a bench.

Those types of ideas are based on theory only.

Randy

digger
Expert
Expert
Posts: 999
Joined: Sun Jan 27, 2008 6:39 am

Re: Ported Ford 289 heads with port energy discussion

Post by digger » Mon Sep 11, 2017 4:56 am

MadBill wrote:FWIW, with all else equal, if you input a higher V.E. into the PipeMax program it of course estimates more power but also suggests a slightly smaller pipe. :-k
mine doesn't, an increase in VE needs more pipe size and the same size as when VE is kept same but peak hp rpm is adjusted to give same hp

e.g. 6800rpm with 110% equals same size as 7511rpm with 100% both have same predicted hp number and pipe size within 0.001". so pipemax primary pipesize is very very strongly correlated to peak hp

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Ported Ford 289 heads with port energy discussion

Post by MadBill » Mon Sep 11, 2017 11:46 am

The info I quoted is from a PipeMax v. 3.7. I've got a newer version filed away somewhere that I haven't loaded yet; guess that's one of its refinements so I better get it cranked up..
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

CGT
Expert
Expert
Posts: 839
Joined: Sun May 10, 2009 12:29 pm

Re: Ported Ford 289 heads with port energy discussion

Post by CGT » Mon Sep 11, 2017 12:36 pm

mag2555 wrote:With a duel pattern Cam and compressions above 11.5 even a 68% Exh to Intake ratio as shown in flow bench testing will work well many times!
What book or article did that information come from and what is well? Absolutes spoken on very dynamically complex processes tend to trip my
b#!%&*t alarm.

GARY C
Guru
Guru
Posts: 3335
Joined: Tue May 14, 2013 10:58 pm

Re: Ported Ford 289 heads with port energy discussion

Post by GARY C » Mon Sep 11, 2017 3:15 pm

Maybe time to start measuring exhaust performance with a sound frequency measurement SFM as oppose to CFM.

User avatar
Stan Weiss
Guru
Guru
Posts: 3344
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA
Contact:

Re: Ported Ford 289 heads with port energy discussion

Post by Stan Weiss » Mon Sep 11, 2017 5:01 pm

CGT wrote:
mag2555 wrote:With a duel pattern Cam and compressions above 11.5 even a 68% Exh to Intake ratio as shown in flow bench testing will work well many times!
What book or article did that information come from and what is well? Absolutes spoken on very dynamically complex processes tend to trip my
b#!%&*t alarm.
Unless things have changed very recently. The 2.9 - 3.0 HP per ci N/A NHRA (500 ci) and Australian Pro Stock (400 ci SB's) are running closer 60% Exhaust to Intake ratio.

Stan
Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Image
http://www.erols.com/srweiss/index.html

mag2555
Guru
Guru
Posts: 2062
Joined: Sun Sep 18, 2011 11:31 am

Re: Ported Ford 289 heads with port energy discussion

Post by mag2555 » Tue Sep 12, 2017 6:29 am

Not only that fact like Stan posted , but look at some of these great performing heads with like a 2.19" Intake valve and yet still just a 1.65" Exh.
These Heads are a built in 70% or less Exh to int ratio no matter how you slice it!

Carnut1
Guru
Guru
Posts: 3215
Joined: Tue Jun 11, 2013 6:32 pm
Location: Melbourne fl.

Re: Ported Ford 289 heads with port energy discussion

Post by Carnut1 » Tue Sep 12, 2017 6:36 am

Hp/cube and rpm make a difference here. Available differential pressure makes it that the intake valve takes presidence so you see larger and larger intake valves and better c/d intake ports. The exhaust valve and ports shrink and even though pumping losses increase for the exhaust the engine still makes more power.
Servedio Cylinder Head Development
631-816-4911
9:00am - 9:00pm EST

randy331
Guru
Guru
Posts: 2542
Joined: Mon Dec 04, 2006 7:30 pm
Location: N.W. MO.

Re: Ported Ford 289 heads with port energy discussion

Post by randy331 » Wed Sep 13, 2017 9:30 am

CGT wrote:
mag2555 wrote:With a duel pattern Cam and compressions above 11.5 even a 68% Exh to Intake ratio as shown in flow bench testing will work well many times!
What book or article did that information come from and what is well? Absolutes spoken on very dynamically complex processes tend to trip my
b#!%&*t alarm.
Those kinda comments are about as comical as 2-3 deg of LSA is worth 30-50 pounds of TQ.

Randy

cspeier
Guru
Guru
Posts: 2476
Joined: Thu Mar 31, 2005 5:31 pm
Location: Hays Kansas
Contact:

Re: Ported Ford 289 heads with port energy discussion

Post by cspeier » Wed Sep 13, 2017 10:28 am

Pipemax recommendations can be spot on for headers. Lengths, and sizes....

David Vizard
Guru
Guru
Posts: 1158
Joined: Thu Jan 15, 2015 12:19 pm

Re: Ported Ford 289 heads with port energy discussion

Post by David Vizard » Wed Sep 13, 2017 4:59 pm

I mentioned this before a year or so ago but intake to exhaust ratios are entirly dependant on the CR.
DV
David Vizard Small Group Performance Seminars - held about every 4 weeks. My shop or your shop. Contact seminar organizer at marvingvx@gmail.com for details.

David Vizard
Guru
Guru
Posts: 1158
Joined: Thu Jan 15, 2015 12:19 pm

Re: Ported Ford 289 heads with port energy discussion

Post by David Vizard » Wed Sep 13, 2017 5:04 pm

cspeier wrote:Pipemax recommendations can be spot on for headers. Lengths, and sizes....
Chad,
It is really rare that I disagree with you but for the engines we most commonly deal with all the commonly used programs are far from accurate.

DV
David Vizard Small Group Performance Seminars - held about every 4 weeks. My shop or your shop. Contact seminar organizer at marvingvx@gmail.com for details.

Warp Speed
Guru
Guru
Posts: 2061
Joined: Wed Jun 25, 2008 1:46 pm
Location: NC

Re: Ported Ford 289 heads with port energy discussion

Post by Warp Speed » Wed Sep 13, 2017 7:47 pm

Stan Weiss wrote:
Unless things have changed very recently. The 2.9 - 3.0 HP per ci N/A NHRA (500 ci) and Australian Pro Stock (400 ci SB's) are running closer 60% Exhaust to Intake ratio.

Stan
Weird huh?!? Lol

Post Reply