low cost intake R&D

[Stubby]

Awhile back, I had a thought on experimenting with different intake manifold setups. To realy optimise an intake you would have to try different runner lengths, taper, diameter. The plenum would also be equaly challenging. I have watched Comp Eleminator guys change ports and plenums with epoxy and hours upon hours of work.

The inline engine has an advantage with everything being inline. :idea:
Picture a box, the length of the head. The side that mates to the head will need to be drilled to match the runners and bolt pattern. The top of the box will need to be removable, and have a nice square hole that will be adaptable for any carb. The depth of the box inside should be sized to allow maybe two 2x8 boards to stack together and fill the box nicely. Layout the desired port spacing and use a good router to carve out two mirror images.(top and bottom) Carve out the desired plenum and open up the carb hole. Insert into box and carve out a carb spacer. Seal the wood, and go test it.

I am sure this method would have some hurdles. However, it would be possible to use templates for precision work in wood or plastic inserts.
With the CNC millwork being as readily available as it is today, it could allow lots of design changes with alot less expense.

A person could also play with dimples, grooves, vortex generators, dilithium crystals and other cool things because you would be able to open it up, modify it and close it up and try it. 8)

I should have shared this way back when I thought about it, but it got pushed into the back of my mind, a place where most things never return from.

 

[80broncoman]

What are you trying to do with this?
Ever thought about a active intake Like a variable runner lenght intake?

 

[XPC66]

Something that might interest you is some intake pipe tests carried out on four pot 1600 EFI Jap motor with stock ECU. It was quite educational seeing an increase of 10 hp by tuning the length to 600mm. It lost that when 300mm and/or 900mm..... makes you wonder at the the CAI kits eh.

For intake runners I tend to use mach harmonic lengths (including port runner). The helmoltz resonator sizing is a bit iffy in my book as are the ABDC° and cylinder volume methods.

 

[Stubby]

What I am getting at is the ability to test different setups without having to modify cast intakes. Imagine enlarging the runners on a cast intake for testing. It is a huge undertaking and may not net the desired results.

With an experimental setup like this, you can carve out a two carb intake complete with two plenums and change the top (or cut two holes and plug the first). Enlarge plenums, runners, change shapes, make it a three carb setup. All without casting anything or fabricating a specific intake. Just make more inserts and modify the top.

The reasons for R&D are many. The theory of the perfect length runner and plenum volume is affected by many factors, no intake is ever perfect. Add the fact that you have to curve those runners and fit it inside the shock towers and this will allow many changes with less cost. After the final design has been arrived at, the inside pieces could be taken to the foundry and the cost of making the patterns will surely be reduced.

I am not talking about any particular type of intake. I am talking about a way to simplify R&D on any type of intake, as long as it is flat.

http://www.fordsix.com/forum/viewtopic.php?t=44436

Look at the intake and the core box. Picture being able to bolt something like that together and test it, open it up, change it and test again. Now think how much easier it is to change it, than the intake. 8)

 

[XPC66]

Trouble is with runners radiusing out from the carby, the runners are all different lengths, so inherently the manifold of pipes is not tuned anyway.

You might be better using some flanged nipples to bolt onto each intake port and use hoses to a plenum to find the best lengths.

 

[fb71]

just like the RamChargers did back in the early 60's

http://main.ramchargers.com/index.html

 

[StrangeRanger]

Some of the CanAm cars of the early 70s used 2 different lengths of air horns on the injectors as a way of maximizing performance at 2 different RPMs giving a torque curve with 2 humps several hundred RPM apart (as if an 8 litre Ch**y needed a wider torque curve )

 

[XFlow_Fairlane]

I wish those can am cars were still around....lots of great inovation on those cars!

 

[XPC66]

Of the falcon sixes here have the long path runners, switching to short path as the revs build.

 

[Thad]

Mazda GT prototype racer had intake runners that telescoped with some mechanism controled by RPM.

Watch on TV as them tuned prior to a race. Each time the engine was rap the runner telescoped down short almost to 2/3 extended length.
The dumby commentator made no comment, don't think he realised what he was seeing.

 

[wallaka]

BMW's sixes have continuously variable length, electronically actuated intakes. Also some of Honda's intakes as well. They just switch between long and short runners though, unlike BMW.

 

[fb71]

They just switch between long and short runners though, unlike BMW.

Mazda started that in '89, and it bled over to Lincoln/Ford (Mark VIII 4.6L DOHC/ Taurus 3.0 Duratec) in 93 and 96, respectively.

Mazda called it VICS (Variable Intake Control System)
Ford called TMRC (Tuned Manifold Runner Control) or VRMC (Variable), depending on the year.

oh, and the Escort GT in '91 had it as well (1.8L DOHC Protege)

 

[Anonymous]

I haven't kept up with this, but some of the Jap dirtbikes had (have?) small resonating chambers attached to the intake runner to aid torque below the tuned rpm band (XPC is suggesting something functionally similar). Nice and simple, no moving parts. IF I recall, there was an aftermarket add-on resonator called a "Roost-Boost."

Is the fact of unequal-length and therefore haphazardly-tuned runners (from a single carb) necessarily a negative? Most here are wanting street engines with non-peaky power. I ride a 2-stroke Yamaha RD-400 with expansion chambers that are pretty mild as these things go, and even so it is peaky enough to be annoying for 95% of the riding I do. What I loved in a race motor I don't care for on the road.

 

[fb71]

Roost-Boost! I forgot about that! I had one on my '79 Suzuki PE250. It did help a little. Incidentally, Matt over on www.fordfestiva.com did a comparison with and without the intake resonance box on the 1.8L DOHC swap into a Festiva that he did. He noted a definate loss of low rpm torque without it. His tests were subjective, not scientific, but he's very thourough.

Smitty, I WANT THAT RD400!!!! I can't find a good one out east here. Or I'll take a Kawi H1...

 

[69Falcon]

The Mazda 787B 4 rotor car that won Le Mans in '91 had telescoping intake runners for optimum performance. 8)

 

[Anonymous]

Jim, d'ya really think I would consign my RD to H#LL? . . . er, Purgatory?

 

[fb71]

well, no, but it was worth a shot! Know anywhere I could find a decent RT360 instead? Then we could get together for a "Blue Haze Across America" tour!