Direct drive SBC

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MARCVINI

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Marcvini,

Why in the world would you think 100LL has variations around the world? It either meets the international specification or it does not. Same thing with jet fuel. It either meets the specification or it does not.
Compare this to automotive fuel, either gasoline or diesel. The specification is set by each country. That induces huge variations around the world.

Tim
I said variations in QUALITY, not "on paper" SPECIFICATIONS... Storage methods, storage time and so forth changes QUALITY of fuels around the world. Avgas included.

Marcvini
 
E

ekimneirbo

Guest
Actually, a substitute for an LS intake (manifold+fuel rails+throttle body), in an SBC, will wigh in 10lbs more. So, your reasoning on that is absolutelly correct. The real problem is using the LS intake in a DDV8 instalation. The throttle body is placed too far forward from the engine and, either oriented to the front or to the rear of the airplane, you will have dificulties adding filter and other hardware without lengthening too much the instalation. That will be translated into a too far forward propeller weight hanging on the nose of an already heavier instalation. What is the solution for that?

By the way: using used parts is COMPLETELY out of question for me.

Marcvini
First, let me address the "used part" concern. Generally I agree with that, but there are some things that are just fine used or reconditioned. A used intake manifold should be of little concern although it is possible one could have a problem. Used heads are much more reasonably priced and it would be no problem to recondition them with better quality valves and springs than OEM. New guides might help and you can often have a better quality guide installed if its even needed. That will drive up the price of the head near to a new one.....but often low mileage heads become available cheaply. So for the most part, there are some parts that will not cause concern even though they are used items.I would also consider items like the flywheel,exhaust manifolds,valve covers,and some of the brackets and bolts to be acceptable. Used parts can save quite a bit of money without causing concern if selected wisely.

The intake problems will vary depending on whether you are running speed density (no MAF required) or using a setup that requires a MAF sensor. GM feels that a certain length (10" if memory serves me) of straight pipe is needed for a MAF to operate properly. If you engine is mounted backwards, it should not be a problem to make a 180 degree bend and run the tube alongside the valve cover to get that length.....or if conditions are favorable to route it downward or upward...then do that. If you run a speed density setup, reverse the intake manifold and install a simple air cleaner on the throttle body.
 

MARCVINI

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First, let me address the "used part" concern... The intake problems...
Regarding new or used parts, it is pretty much up to ones preferences. And at least for me, as I live in the "down under" part o Brazil and I will have to source parts in the US, it is easier to pick them new/ready for my intent.

As for the intake problems, believe-me: MAF isn´t the real problem. The problem is the space available for atatching intake stuff to the LSx throtle body, no matter how you orient the intake manifold. Either oriented to the front or to the rear of the airplane, you will have to lengthen the instalation a lot to acomodate things inside the cowling, and that will translate into extra balance measures for an already heavier-than-stock instalation.

Marcvini
 

crytes

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How much do you think you need attached to a throttle body? Unless you're plumbing a turbo you just need to make room for a filter or if you're feeling froggy an interface for a filter box/ram air in the cowling if you're running inverted you should have plenty of room below the engine.
 

MARCVINI

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How much do you think you need attached to a throttle body? Unless you're plumbing a turbo you just need to make room for a filter or if you're feeling froggy an interface for a filter box/ram air in the cowling if you're running inverted you should have plenty of room below the engine.
A "decent" filter, alone, will require at least 5 inches of space, if not more, from the throttle body on. So, throttle body + filter will "eat" at least 7 to 8 inches, if not more. And if you use a forward facing intake, à la Vans RV´s, you can count on needing at least 12 inches from the engine. Even if you don´t use this set up, but use tubing for placing the filter elsewhere in the cowling, you will have a lot of bulk too to deal with.

A hint: there are pictures of an LS3 engine on post #868. I ask you to see how far from the engine the throttle body is placed. Imagine inverting the intake manifold in order to mind "exercise" all possibilities and, eventually, help me solve this issue. By the way: drawings/sketches are welcome.

Marcvini
 

crytes

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I'll find some dimensions and sketch what i have in mind when I get a moment I don't get a break in my A class until the 17th so I might not find time until then. what I have in mind is 180 degree bend between the throttle body and the filter even with the required bend radius I don't think it will extend much farther aft of the serpentine belt system already there so the limiting factor will be ground clearance and your individual application will determine your desired thrust line and how high you're mounting the engine.
 

MARCVINI

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I'll find some dimensions and sketch what i have in mind when I get a moment I don't get a break in my A class until the 17th so I might not find time until then. what I have in mind is 180 degree bend between the throttle body and the filter even with the required bend radius I don't think it will extend much farther aft of the serpentine belt system already there so the limiting factor will be ground clearance and your individual application will determine your desired thrust line and how high you're mounting the engine.
I appreciate your interest and thank you for your input. Here is a "rough" sketch of my intended instalation as it may serve you as a reference. The cowl was lengthened by about 3 or 4 inches. Distance from the engine to the prop spinner is about 5 inches. Red engine is a Chevy Sbc. 29.42 is the length of the SBC engine. LS3 engine is already inverted and scale-adjusted to the other objects depicted. Length of LS3 is abou 27.5 inches.

Glasair Sportsman for Homebuilt Forum.jpg

Marcvini
 

MARCVINI

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Intake Manifold/Cylinder Head Gasket: the following design seem to be perfect for IDDV8 SBF instalations, specially for non-air-gap-style manifolds, since it would naturally drain oil from the lifter valley to the cylinder heads.

Victor Reinz intake manifold gasket.jpg Victor Intake manifold gasket.jpg

Anyone has any experience on them? Are there similar ones for Chevy SBCs or BBCs?

Marcvini
 

crytes

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idd-ls ram air concept.jpg It's not close to scale but i think it conveys the idea only Clearance issues I see is if your application matches the picture you posted is weather the under cowl portion of the nose wheel strut is too close to the engine. I believe the heads are slightly taller than the intake so until you get to the cowl intake you cold air tube should be running right between them and below your fuel rail.
 

MARCVINI

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(...) Clearance issues I see is if your application matches the picture you posted is weather the under cowl portion of the nose wheel strut is too close to the engine. (...)
I appreciate your interest and thank you very much for drawing that sketch. It is a pretty nice idea and it is perfect for taildragger airplanes. THE PROBLEM is for tricycle geared aircraft, since, as you have also found, that set up will interfere with the gear leg, unless you lengthen the instalation. Hence the "bulkiness" of the LSx intake that I have mentioned before...

You see, you will have that same problem if you invert the intake manifold, placing the throttle body oriented forward: you will need to lenghten the prop extension by quite a lot in order to "criate" room for the intake add ons, whatever they might be.

Marcvini
 

Toobuilder

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I appreciate your interest and thank you very much for drawing that sketch. It is a pretty nice idea and it is perfect for taildragger airplanes. THE PROBLEM is for tricycle geared aircraft...
The Glasstar can be built as a taildragger.... Is that not an option for you for some reason?
 

MARCVINI

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The Glasstar can be built as a taildragger.... Is that not an option for you for some reason?
Yes, it is an option for me. I actually like taildraggers better than tricycles. BUT, I want to keep my airplane as versatile as possible, I mean, to be capable of using all the factory landing gear options.

On the other hand, I like so much the idea of IDDV8 airplanes that I feel like I have to find solutions that can be used by anyone. I intend to document the whole process (I am already doing it...) in order to write a book, paper, whatever is necessary for sharing my experiences (and the learning process as well) on the regard. I FEEL THE THING IS BIGGER THAN ME OR MY OWN NECESSITIES.

Marcvini
 

crytes

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Do they even make a LS intake manifold with a vertical intake port? As far as my idea minimum bend radius will make or break your clearance. You could build as a taildragger but unless you want a taildragger I would prefer to keep modification for an engine install to the engine as much as possible.
 

MARCVINI

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Do they even make a LS intake manifold with a vertical intake port? As far as my idea minimum bend radius will make or break your clearance. You could build as a taildragger but unless you want a taildragger I would prefer to keep modification for an engine install to the engine as much as possible.
As far as I know, the only intake set up with a vertical port is a "normal" aluminum carb-style. Chevy Performance has them both in single and dual plane forms. This would solve the clearance issue, BUT with a weight penalty of at least 10lbs. Maybe it could be well worth a trade off, since the engine could be mounted as close as possible to the firewall and one could use a shorter prop extension.

Marcvini
 

MARCVINI

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The more I read and research, the more Stol´s instalation makes sense to me... I have finally figured out the reason for the many "XXXX" replies of his on most threads of this forum.

Marcvini
 

Streffpilot

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Hey, STOL, do you hve any hypothesis on what we could see for fuel burn if we were to run a ls/sbc in place of a 360? I usually plan on about 7.5 gph in the 172 out of the 360.
 

stol

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Hey, STOL, do you hve any hypothesis on what we could see for fuel burn if we were to run a ls/sbc in place of a 360? I usually plan on about 7.5 gph in the 172 out of the 360.
My gut feeling is your cruise GPM's will be pretty close to a 0-360 since the Lyc /Conti's are pretty good at BSFC in cruise.. Where they get fuel thirsty is at full power setting like climb or wide open cruise.. They need additional fuel for cooling purposes where a liquid cooled motor can shed it's heat out the radiator. IMHO. YMMV..
 

Toobuilder

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Make sure you characterize the term "wide open" properly. Many aircraft engines are operated with the throttle wide open (against the stop) in cruise.
 

MARCVINI

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To see the miriad of Belted Airpower RVs flying reliably and inexpensively for so many years, makes me think that, altough quite possible, this IDDV8 endeavor stops making sense, especially costs wise. So, I am oficially giving up the IDDV8 pursuit in favor of a belt drive PSRU solution for my auto conversion endeavor.

As for now, I am evaluating the feasibility of stuffing a belt drive reduced Ford 502 in a Sportsman. If it doesn´t prove viable, maybe upgrading to a belt drive reduced LS3 in an RV 10. Time to make calculations, especially budget wise.

But I can´t deny that, to join this forum and thread, and exchange information with all of you guys has given me invaluable information and instruction on the auto conversion subject. And more and more I believe that the typical American V8 engine is the redeemer of experimental aviation.

Thanks everyone for their contribution and atention to my ideas.

Marcvini
 
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