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Optimized runner lengths?

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Firepower354
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Optimized runner lengths?

Post #1 by Firepower354 » Fri Oct 18, 2013 10:56 am

Using the available calculators online, our Big Six would seem to "want" some pretty lengthy plumbing. Has any one tried?
Logistics and packaging would be difficult, as would keeping fuel suspended.
It gets 10MPG, but goes up to 14 if I lie.

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80broncoman
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Re: Optimized runner lengths?

Post #2 by 80broncoman » Fri Oct 18, 2013 11:18 am

Whatever The length its only going to be Optimized for one particular RPM.
Anything higher or lower and it will suffer.
Why not come up with a dual length runner intake?
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80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: Optimized runner lengths?

Post #3 by CNC-Dude » Fri Oct 18, 2013 1:09 pm

The factory EFI lower intake seems like a good platform to start with, since it already is tailored for the 300 already. They are cheap and on ebay all the time. The FTF has also made an intake or two using them as well. I am making patterns to cast a performance specific intake manifold for the big 6's. What is going to be your primary goal for yours, street, race or both?
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Re: Optimized runner lengths?

Post #4 by Firepower354 » Fri Oct 18, 2013 8:42 pm

80B, agreed, any manifold is going to "tune" at a particular RPM. Fortunately, mine's in an RV, so I want it on the curve at 50 MPH.
Multiple runner lengths, like the EFI/Redline mutation I'm pondering, is going to have some cylinders working better at varied revs, widening but lowering the meat of the curve. It's likely the way I'll end up going, for E350 space constraints. Unless,,, I put the carb on the driver's side, runners over the manifold. Then they could converge more gradually and meet at a common heated plenum.


CNC, my application is 100% street, an RV. I have an EFI lower. It seemed a convenient way to get started. If time and money were in better supply, I'd build a steel long-runner intake and header setup, tuned in for my cruise speed.

I can see where street/strip use, shorter runners to work at several order of harmonic points, fattening the area under the curve, would be ideal.
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #5 by 80broncoman » Sat Oct 19, 2013 9:14 am

You don't have to go multi length just because its a inline. Just look at how Chrysler made a equal length runner intake for the 4.0L inline six on the 99-06 Jeep engine. Just keep in mine its a dry manifold (EFI) and might not like wet flow.
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Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: Optimized runner lengths?

Post #6 by MechRick » Sat Oct 19, 2013 2:57 pm

80broncoman wrote:The length its only going to be Optimized for one particular RPM.


Granted, but there will be several lesser peaks. The sonic portion of the tuning works over several different harmonics. The Nascar boys aim for the 3rd, at pretty high rpm. Tuning for lower (1st, 2nd) results in a bigger pressure wave boost, but a narrower rpm spread.

The EFI upper is a split plenum design. Think of a tri-y header in reverse. Split plenums give you broader tuning similar to dual plane intakes for carb applications. I think this is one of the reasons why the EFI sixes have such a broad, flat torque curve.

The problem with long runner intakes is they can't flow enough air at higher rpms. This is the reason the oem's have gone to elaborate multi runner intakes with rpm activated butterflies. That way you can have your small cross section long runner low rpm tuning, and have your short fat high rpm runner piping too.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: Optimized runner lengths?

Post #7 by Firepower354 » Sat Oct 19, 2013 3:04 pm

80broncoman wrote:You don't have to go multi length just because its a inline. Just look at how Chrysler made a equal length runner intake for the 4.0L inline six on the 99-06 Jeep engine. Just keep in mine its a dry manifold (EFI) and might not like wet flow.



I was looking at the similar BMW manifolds, and had the same wet-flow concerns. I'm guessing the runner will need some heat beyond just the plenum.
It gets 10MPG, but goes up to 14 if I lie.

Firepower354
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Re: Optimized runner lengths?

Post #8 by Firepower354 » Sat Oct 19, 2013 3:14 pm

Other end of the cycle, I'd like a set of these. Maybe even some slip-fit primary extensions to play with length.

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It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #9 by MechRick » Sat Oct 19, 2013 3:21 pm

Firepower354 wrote:Fortunately, mine's in an RV, so I want it on the curve at 50 MPH.


I always wondered how the big six would work in a small class C RV.

I know when I'm towing above 10,000 lbs total (combined) weight, the six starts to struggle a bit. What is the weight of the average 23 ft class C? I know the six was used in medium duty trucks, so the capability should be there. Anyone venture how much HP it takes to keep an RV rolling along on level ground at 50-55 mph?

The real question is whether there is a mpg improvement by going to the smaller engine.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

Firepower354
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Re: Optimized runner lengths?

Post #10 by Firepower354 » Sat Oct 19, 2013 3:47 pm

It gets around fine. 3 on the tree, manual windows, Alumalite job. Pretty bare-bones. Vacation isn't supposed to be a rush, right? It ain't! lol
3.55 gears with 8.50-16.5's
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #11 by THE FRENCHTOWN FLYER » Sat Oct 19, 2013 9:42 pm

When I had a 300 / 4-spd OD manual / 9" 3.00 Econoline as a tow vehicle it pulled my race car acceptably around the midwest OK. But a couple of times I towed to a race in Bristol TN and it was horrible trying to tow in the mountains. Downshifting from OD to direct and then to 2nd was frequent and I actually became an impediment to the flow of traffic. Unfun.
FORD 300 INLINE SIX - THE BEST KEPT SECRET IN DRAG RACING

Firepower354
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Re: Optimized runner lengths?

Post #12 by Firepower354 » Sun Oct 20, 2013 9:12 am

I looked for a SROD 4-speed, and had even bought a ZF5, but the Toploader 3 has served it for 170K and the tree-shift makes the floor uncluttered. Added drag from the top bunk make OD iffy any way. 2000 RPM suits it. The engine is a little tired, so I'm contemplating a freshen up, swirl-port update, or even a dreaded bent-8 351W or 400M, SP-2P swap. 10MPG is all it pulls now. The long-runner and freshen up may help, and I doubt the bigger mill would hurt. I envisioned small turbo, and even NOS in small doses for the big hills. Most running will be to the Traverse City area (old home) from Flint. M115 is hilly but it pulls them.
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #13 by Firepower354 » Sun Oct 20, 2013 10:38 am

Here's what I'm pushing around with the 300.
http://i178.photobucket.com/albums/w272 ... oto554.jpg
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #14 by 80broncoman » Sun Oct 20, 2013 2:05 pm

I have an idea For Variable runner length EFI but It would be very hard to pack it under the hood of a econoline chassis.
And it would NOT work with a carb at all.
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Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: Optimized runner lengths?

Post #15 by Firepower354 » Sun Oct 20, 2013 2:28 pm

Interesting. I can envision a dual-length runner carb setup, in Econoline package. Pretty much my EFI-base, 2v top, with drops out the bottom.
I can't draw, but this is sorta what I mean. A pair of small 2v carbs?
http://poisson.me.dal.ca/~dp_06_9/intake/flap2.jpg

I see lots of OE dual-length, but only a variable in bike use.

Racers, sure:
http://i141.photobucket.com/albums/r48/ ... _large.jpg
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #16 by 80broncoman » Sun Oct 20, 2013 3:00 pm

Firepower354 wrote:Interesting. I can envision a dual-length runner carb setup, in Econoline package. Pretty much my EFI-base, 2v top, with drops out the bottom.
I can't draw, but this is sorta what I mean. A pair of small 2v carbs?
http://poisson.me.dal.ca/~dp_06_9/intake/flap2.jpg

I see lots of OE dual-length, but only a variable in bike use.

Racers, sure:
http://i141.photobucket.com/albums/r48/ ... _large.jpg


your #1 is close to my idea
Imagine a 10-12 inch tube with a 3 inch tube inside that. Mounted on top of the lower factory EFI intake. You fee the air down either end or the center holes of the center (and outer tube).
Then the inner tube has holes that line up with the holes in the bottom of the outer tube and the lower intake.
That is the short runner position.
for the longer position you just rotate the inner tube enough so the air must exit the inner tube at the say the 4 oclock position and the air must run all the way around to he 6 oclock position to exit into the lower intake.
Make sense??

OR you forget all this stuff and pressurize the intake tract with a turbo at 5PSI and really wake up a stock 300.
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: Optimized runner lengths?

Post #17 by Firepower354 » Mon Oct 21, 2013 10:49 am

I can dig it. Turbo hasn't been ruled out. The oil-burner turbos seem reasonable and durable.
Simple, Holley 2v draw-through, with water and/or E85 injection for detonation control on the long hills?
I still don't like the stock manifold, but it's likely ok for a 3-5PSI setup?
It gets 10MPG, but goes up to 14 if I lie.

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Re: Optimized runner lengths?

Post #18 by BIG 6 farmer » Mon Oct 21, 2013 6:01 pm

Look on Keystoneturbo LLC :thumbup: they make draw through kits for farm Tractors & one for 220/240 6 cyl. IHC Trucks. Cool pictures, and roadtest vidios :D Shows how little it takes to wake up those Engines... Would apply well to our 300 sixes :hmmm:
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

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Re: Optimized runner lengths?

Post #19 by Firepower354 » Mon Oct 21, 2013 6:43 pm

Inspiring stuff!

Without having to bush rods or use a short ring stack, 390 slugs, with the step trimmed? I like quench.
https://www.uempistons.com/index.php?ma ... 32bb6a5fc5
It gets 10MPG, but goes up to 14 if I lie.

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