Chad's Intake Article

[Schmleff]

Great work!

Thanks mang.

[Soneraifred]

Chad:
Great article.  My Monnett 1850 originally had cast intakes with a single plenum, and I saw-cut them to add a divider.  I don't remember what the end result was as it was a long time ago, and I'm getting old.  I'm currently running GPACS welded steel intakes.  What does it all mean?  I don't know...

Fred

[privatepilot03]

thanks guys.  More to follow!

I think I'll do connecting rods next based on the conversation that's been stirred up on the conversions group.

Any other requests?

chad

[jwalin]

I enjoyed the article also......I just wonder how I can apply it to a Type 4, since the intake design is so much different.  I guess keeping the intakes separate for a longer distance would be my best guess.  There really isn't a way, as far as I see it, to make one plenum right up to the head on a T4 due to the center bolts.

Well, I am tool far away from that to worry about it now!!
Jeff

p.s.  I hope to write an article about my attempt to coax a Sonerai engine out of a Type 4 powerplant.  Anyone interested?  I know it has been done before and I won't be treading on any new ground.....but I haven't ever found a detailed writeup of the T4 as a flight engine......

[splischke]

<Snip>
I hope to write an article about my attempt to coax a Sonerai engine out of a Type 4 powerplant.  Anyone interested?
<Snip>

I think it will make for interesting reading.  I'll be happy to publish it on Sonerai.net.

-Scott

[EricM]

I had a simular problem only the plugs on the left side were very rich and the plugs on the right side were lean. I determined my problem was caused by the Position of the Revflow carb on my engine.
I added a gizmo in front of the carb to swirl the air as it enters hoping this would help atomize the fuel and more evenly distribute the air/fuel mixture. The difference was amazing. The engine runs much smoother at all rpm's and static WOT is now 100 rpm higher, plus all the plugs are now a beautiful golden brown color. Here's a  pic. It's made of 2" ABS pipe and 1/8" by 3/4" aluminum flat bar.

Eric Mercer

[jwalin]

I've seen a similar device for cars.....always thought it would inhibit performance at high RPM.....I guess it just goes to show you how some ideas are better for our applications than other's!!  Since we don't run the high RPM's, no trouble with the flow...

I am glad all this information and discussion is happening!!  I love this forum!!

Thanks for creating it!!

I will write that article about the T4.  I just recieved a '75 Porsche 914 engine/tranny combo last saturday.....I will take pictures and document the whole process for all to see if that is acceptable......hopefully it will end up being a series of the entire build process.

Jeff

[EricM]

I gave the wrong dimensions for the flat bar I used. The real measurements are 1/16" by 3/4". I used hardware store aluminum flat bar because I already had some and it was easy to twist to the shape I wanted. I'll post some more pictures to the photo section later today.

Eric Mercer

[Schmleff]

For what its worth, I own an 88 Toyota Alltrac Turbo. Its a 240hp 2.0L engine.

The car has a system that Toyota calls TVIS.

In the intake track, right before the head and injectors, there is a set of butterfly valves, much like the butterfly on an old carb. Under 4300 rpms, the valves remain partially closed to cause turbulence in the intake track. When the rpm's exceed 4300, the butterflies become a restriction so the "TVIS" servo flips them to the open position allowing a free flowing intake.

So, the idea of creating turbulence at low rpm is not some hair brained idea. I am sure Toyota spent a great deal of money developing the concept. Consequently, Toyota dominated the World Rally Circuit with this car and engine in the late 80's and early 90's.

[Karmarepair]

I just bought a set of these manifolds from GPASC.  The instructions that came with them just about duplicated Chad's article.  They also note the problem of unequal fuel distribution was worse with "injector" rather than "float bowl" carbs.  They also suggested running a little carb heat - which has the same effect on improving the mixture that the manifold heat ON EVERY VW CAR EVER MADE (and many of the early VW aero conversions) has.  Lately, AvWeb.com has suggested running carb heat to improve mixture distribution to allow more aggressive leaning on carburated engines.

I also wasn't too pleased with the quality of the castings. They are rough, a little mis-shapen, crudely machined, and have some inclusions and surface blowholes. And the holes for the studs are, to my mind, rather oversized, so it's hard to match port the manifolds to the heads if you're so inclined - the manifolds can move relative to the heads (before you cinch the nuts up) too much for my taste.

I was surprised to see they have little nubs for adding port injectors.

RE Fred's manifolds, the old (and I just checked, new) AeroVee manifolds for Dual Port heads had a big plenum just before the heads, so that the incoming charge just about came to a stop (due to the expansion in flow area, like a venturi in reverse), and the fuel dropped out of "solution" with the air.  I've never seen an intake manifold like this  on any other engine.  Usually the plenum, if present, is just after the carb, and the runners are constant diameter from the plenum to the intake port, or as near as can be managed.  Putting a divider into the  AeroVee manifolds made them look more like individual runners.  At least that's my theory.  I haven't heard too much bitching about poor mixture distribution in the new AeroVee engines, and they have the same design, so I could be all wet.

The GPASC aluminum manifolds are not, IMHO as bad in this way as the AeroVee deals, but there is still an expansion going on near the intake port.  The GPASC "KR" style manifold, with individual runners for each cylinder is, from a flow perspective, a better choice, but it's probably nearly twice as heavy as the "Y-pipe" plus aluminum castings.

Single Port heads and manifolds don't have this problem.  Too bad new Single Port heads are so scarce.  And GPASC has nothing "off the shelf" that fits them.

[radfordc]

Thanks for this idea...it works great.  I just put one on my Aerovee engine and the right rear EGT is now 10 degrees cooler than the left rear instead of 70 degrees hotter like before.  The CHT went down 20 degrees too.

Charlie

I had a simular problem only the plugs on the left side were very rich and the plugs on the right side were lean. I determined my problem was caused by the Position of the Revflow carb on my engine.
I added a gizmo in front of the carb to swirl the air as it enters hoping this would help atomize the fuel and more evenly distribute the air/fuel mixture. The difference was amazing. The engine runs much smoother at all rpm's and static WOT is now 100 rpm higher, plus all the plugs are now a beautiful golden brown color. Here's a  pic. It's made of 2" ABS pipe and 1/8" by 3/4" aluminum flat bar.

Eric Mercer

[EricM]

Glad to hear that someone else is getting good results from the "gizmo".

On my latest one, I used .040 aluminum instead of flatbar and it works fine.

Is there anyone else who has tried a "gizmo" on their plane?

Eric

[phzabriskie]

I am running a purchased product called "Turbonator" in my Jeep GrandCherokee.  Trying to improve the 13mpg in the 5.2V8. No hard results yet, but 2 tanks of gas seems to be up to 15mpg. It is the exact same principle as the gizmo and good construction of 1 single piece of stainless steel. I will definetly use the gizmo with my Revmaster and what ever carb I settle on.  Juergen was doing some study on tuning the intake manifold length for optimum pressure.  It should be interesting to follow that also.  Cheers, Pete.