quote Originally posted by fieroboom: Smokey Yunick. 250hp from a Duke, intake manifold temps @ 440o. The only internals he changed was the crank to facilitate his fuel vapor design. Part of his design included a turbocharger (which he called the "homogenizer") at the intake providing a maximum boost of 15psi. Not an argument, just food for thought...

I must repectfully remain skeptical. Everything that I've seen in the Duke engine tells me that its not going to make 250HP and stay together. The Duke was designed as an economy engine and fulfills its function well. You can do what Stickman did for more power but 250HP?????? I have serious doubts about that claim.

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87GT - 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

I thought that they didn't stay together?

quote Originally posted by Dennis LaGrua: I must repectfully remain skeptical. Everything that I've seen in the Duke engine tells me that its not going to make 250HP and stay together. The Duke was designed as an economy engine and fulfills its function well. You can do what Stickman did for more power but 250HP?????? I have serious doubts about that claim.

I never said I got 250hp But I'll bet it's more than a stock V-6. I think the stock block can hold 250hp if it has the marine crank. Wether the stock head could be made to flow well enough to make 250hp is doubtful. But an iron SD head can be had for around $500-$600.

quote Originally posted by The_Stickman2: There is aftermarket everything for the Duke. I don't agree that the heads are that weak. I have had overheated Dukes with no problem.The block can is better than most give it credit for. Not saying it is a rock. Just that it can hold more hp than most give it credit for. I'll say this again, I have never seen a crank failure. Not saying it doesn't flex, just never seen a failure. The only block failures I have seen personally are when the rods come thru the block.

AMEN!

quote Originally posted by The_Stickman2: There is aftermarket everything for the Duke. I don't agree that the heads are that weak. I have had overheated Dukes with no problem.The block can is better than most give it credit for. Not saying it is a rock. Just that it can hold more hp than most give it credit for. I'll say this again, I have never seen a crank failure. Not saying it doesn't flex, just never seen a failure. The only block failures I have seen personally are when the rods come thru the block.

and they still run after they punch a hole in the block(personally saw one a friend took out of a fiero, someone asked him to see what was wrong with it); the hole was the size of my fist.

quote Originally posted by Toddster: True. Sorry but your head is warped and cracked. Just because your engine is still running doesn't mean it is not damaged. The space, for example, between the #2 and #3 head chamber is about 1/8 of an inch. If you overheat your engine just once this sliver of metal will split. Yours is split. I guarantee it. The result is that you will never be able to keep a head gasket from blowing. You will keep blowing head gaskets, and eventually oil and coolant leaks will form too. I'll give you an example of the weakness of the stock head. I rebuilt a 1988 Duke once (Perfectly good head). I drove the car across several states and on a late cold night pulled into a gas station for a fill up. After getting back in the car a cloud of white smoke poured form the exhaust. There was nothing wrong with the car. The reason was that the head had cooled down and warped letting some coolant into the cylinders. After a minute the white smoke dissipated and the car was fine. Just because the engine was so warm and the temp outside was so cold the head warped for a moment. That is how bad the head is on the Duke.

I respectfully disagree I believe the duke is one of the most underrated engines GM ever built, Bullet the engine wasn't but the damn things can take enough punishment to warrant my respect sure you won't smoke anything on the road but its cheap and easy to fix and you don't have to pull it to work on it

Don't let the others talk you out of it, I have circle track raced these motors for several years and never had a crank break. I have however broke a few rods and spun crank bearnings, these problems were usually from an oil system problem were the oil pump pick up was starved of oil.

quote Originally posted by fieroboom: Smokey Yunick. 250hp from a Duke, intake manifold temps @ 440o. The only internals he changed was the crank to facilitate his fuel vapor design. Part of his design included a turbocharger (which he called the "homogenizer") at the intake providing a maximum boost of 15psi. Not an argument, just food for thought...

Wow, now that's something else.... Unfortunately, you have to tear the entire engine appart to change the crank, so you're probably better off changing the other parts while you have it all disassembled right?

quote Originally posted by 151 racer: Don't let the others talk you out of it, I have circle track raced these motors for several years and never had a crank break. I have however broke a few rods and spun crank bearnings, these problems were usually from an oil system problem were the oil pump pick up was starved of oil.

hey, mate; what do you do to them to run circle track; is it something close to these stock car guys
http://www.msministock.com/2007/tech.html

*bump*

just a free bump. this sounds interesting. I wouldn't do it personally, but I think it would be something to see it done. Keep up the good work, and I have the thread bookmarked now. Oh yah, speaking of holes in blocks, I blew #2 on an 86 I had....drove it 5 blocks from the bank to the house. Sounded a little "rough" and didn't idle real smooth for some reason, but it would start up to the day I sold the car, lol.

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

another free bump i have a simmiler thread going and i was wondering what you are doing for fuel?

Why not just turbo it? It seems to be the 4-banger way. All I would do is spring for custom rods and a real good balancing. Oh yeah, forged pistons. The small amount of lag from the turbo will help cushion the engine on takeoff. A turbo from a T-bird would probably be enough.

Vinny

quote Originally posted by vinny: Why not just turbo it? It seems to be the 4-banger way. All I would do is spring for custom rods and a real good balancing. Oh yeah, forged pistons. The small amount of lag from the turbo will help cushion the engine on takeoff. A turbo from a T-bird would probably be enough. Vinny

There really isn't much room to take advantage of the exhaust system is there?

Well.........I don't know. There should be more than any V6/V8 that is turbo'd.

you could run a turbo there is room even for an intercooler but even with a new rotating assembly i would be worred about the bock and head altho that may just be my parinoid suspision also i think you could safly run almost 5 lbs on a duke if you droped the compression to 8.5-1 (think bigger combustion chamber in the heads or maybe a thicker head gasket) that is if and only if you can have complete controll over detonation

Well you would want it to be built strong and managed as in managment system. Use ARP bolts and copper head gaskets you could get maybe 10psi out of it? I'd try it if I had money to burn.

Vinny

im going to build a duke its going to be NA for now but when i get it done and can afford the SD head i think it might be geting a small garret runing some light boost with wathermeth injectiong and a water to air inter cooler then, the plan is to get the SD block and crank lower the compression down and run around 20ish pounds but that is about a year or two away

quote Originally posted by fieroboom: Go for a full-blown Duke man! Build that sucker from top to bottom. The above Duke claims around 350hp

I believe that's a Super Duty 4. A Duke head wouldn't flow enough air and a Duke crank wouldn't take the power.



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3.4L S/C 87 GT www.fierosound.com
2002/2003/2004 World of Wheels Winner &
Multiple IASCA Stereo Award Winner
My SD4 Indy www.fiero.nl/forum/Forum2/HTML/096075.html

[This message has been edited by fierosound (edited 01-07-2009).]

quote Originally posted by White 84 SE: Yea that's right. I am developing a supercharger for my Duke.

Contact Rimmer Engineering. Looks like a manifold for the 2.5L http://www.jpmagazine.com/howto/5472/index.html

EDIT: looks like they've been out of business for some time now.

[This message has been edited by fierosound (edited 01-07-2009).]

the jeep engine is the old rear will drive duke is it not? the same block and crank as a 130HP mercruiser engine .
duke cranks dont break .but at high revs and high HP they flex , causing the rods to break .the result is still the same , the engine gets destroyed .

The Jeep engine is the AMC 150 cu in pushrod non-crossflow engine. Its a derivative of the 4.0. It has nothing in common with the duke except the bellhousing face happens to be the same since the development work was done at the same time Jeep was buying 2.8s and 2.5 (151s) from GM.

so this amc engine has the same bell housing pattern as a fiero duke?

yup it has the same bell housing pattern; i was looking at the crank(2.5 mains, 2.125 rod; both of which could be cut down to the specs. of the iron duke, if it's got the same length; might have to use the 150 damper(the jeep crank weighs 38lbs)besides it would change the stroke 3.00 vs 3.188

[This message has been edited by baldlobo (edited 01-07-2009).]

Hey there all.

Well I figured I needed more information regarding the design of a supercharger and have been at it for a few weeks. Purchased a book called "Supercharging the Small Engine" which was helpful but mostly internet info gathering. Anyway I've settled on a Vane Type design. It is considered obsolete but it is big with vintage car owners especially the smaller displacement cars like old VW beetles and MGs, and Corvairs also. I think it's time to take another look at these compressors. They are true compressors in that they compress the air unlike the mixed approach of the Root style or Screw types. They also have a consistant pressure relationship to RPM in that pressure goes up evenly with RPM whre the Centrifugal climbs up in multiples where boost at 4000 RPM can be triple that of 3000 RPM. This would surely break a Duke. By the way a turbo charger is a centrifugal of course. Well so that's my understanding so far. So here's the essential design I am going with. Ordered the Aluminum and it's on it's way. A357....I think. It has a good amount of Zinc for rigidness and a touch of copper and manganese for greater strength with a bit of flex temperence. Any way this project has been kinda exciting and I cant wait to begin the mold.
Oh yea, itll be a 6" chamber by 3" which may be too small for a 151 but again Im just playing it safe and will melt the metal down if I want to double compressor displacement to better match the Duke. Then again it might be good enough for 20 HP boost who knows at this point?

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84 2.5L Holley TBI Manual Trans White

[This message has been edited by White 84 SE (edited 01-07-2009).]

its hard to see the drawing, but it kinda reminds of me a rotory engine the way the drawing is made.

There I fixed it a bit.... Ya know an engine is essentially an air compressor add gasoline....

quote Originally posted by White 84 SE:

Huh... can't say as I've ever seen something like that before... as it spins, those little walls move in and out by centrifugal force and keep an approximate seal right? But, it looks like it has to decompress the air before it compresses it if I'm looking at it right... Shouldn't the intake be a larger chamber then the output? I don't know much about 'chargers or anything... it's just what seems to make sense to me, so I'm very likely mistaken.

EDIT: Although, this isn't a 3-D representation, so maybe it's taller? Also, make sure that the inlet/outlets have space above them, or those fins will extend into the ports and cause all sorts of chaos.

[This message has been edited by Twilight Fenrir (edited 01-07-2009).]

are you building one of these style of superchargers?

quote Originally posted by Twilight Fenrir: Huh... can't say as I've ever seen something like that before... as it spins, those little walls move in and out by centrifugal force and keep an approximate seal right? But, it looks like it has to decompress the air before it compresses it if I'm looking at it right... Shouldn't the intake be a larger chamber then the output? I don't know much about 'chargers or anything... it's just what seems to make sense to me, so I'm very likely mistaken. EDIT: Although, this isn't a 3-D representation, so maybe it's taller? Also, make sure that the inlet/outlets have space above them, or those fins will extend into the ports and cause all sorts of chaos.

Yea Man, The intake is on the right and I have it at 2" but with wider holes in the side wall so I think it will breath good. On the left you will see the chamber compresses the air until it reaches pretty small and then the openings for that side come in. By the way the ports will be circular and 1/3 the area of the over all intake/out port. The Vanes will jut out via centrifugal force and it will touch the sides of the compression chamber and roll via the roller pins. These pins will be supported via the wall at all times. Kinda like when water goes down a drain yet a person can stand on the grate.

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84 2.5L Holley TBI Manual Trans White

quote Originally posted by White 84 SE: These pins will be supported via the wall at all times. Kinda like when water goes down a drain yet a person can stand on the grate.

What keeps the roller atatched to the vain? If you put a pair of tabs on the top and bottom of the vain that extend over it (like forks on a bicycle wheel) wouldn't that compromise the seal at the top and bottom? Maybe you'd have to extend the side portions a few more degrees around the curve to naturally keep them in?

For that matter, what keeps the seal at the top and bottom? Are you planning something like a water-wheel, two disks with the paddles in between? That's the simplest way I can think of, but then what happens to the top and bottoms of the vains as they extend? if they don't press against the walls, they won't make a seal. And, I have no idea how to counter this problem...

quote Originally posted by The_Stickman2: I never said I got 250hp But I'll bet it's more than a stock V-6. I think the stock block can hold 250hp if it has the marine crank. Wether the stock head could be made to flow well enough to make 250hp is doubtful. But an iron SD head can be had for around $500-$600.

OOPs a misunderstanding. I am referring to Smokey Yunicks Fiero. The claim of 250HP and 50MPG was made with his unusual Duke. As for what your Duke is making I would not venture to guess. You know it best and you usually tell it straight. If I were building a Duke I would use your formula. While others have tried and failed, your performance Duke engine has run making more horsepower, with reliability and longevity. Its an achievement for sure.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
87GT - 3.4L Turbocharged engine, modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Twilight Fenrir: What keeps the roller atatched to the vain? If you put a pair of tabs on the top and bottom of the vain that extend over it (like forks on a bicycle wheel) wouldn't that compromise the seal at the top and bottom? Maybe you'd have to extend the side portions a few more degrees around the curve to naturally keep them in? For that matter, what keeps the seal at the top and bottom? Are you planning something like a water-wheel, two disks with the paddles in between? That's the simplest way I can think of, but then what happens to the top and bottoms of the vains as they extend? if they don't press against the walls, they won't make a seal. And, I have no idea how to counter this problem...

What I was thinking was that if the vanes where concave where it touched the rollers and had little nubs such as in a watch wrist band where the face joins the band it would become much like a bearing. Actually bearing pins can be ordered just like that. Since there will not be much pressure on the rollers and the vane will be subject to more centrifigal force than the roller it would naturally glide and keep AND be air leak proof I think more than if they were close but not touching. As for the vanes as they extend they ought to be leak proof if they are lubricated which forms a bit of a seal to air.

This Roller Vane idea is my own and I havent seen it on any superchargers so it is frontierish. I was looking at a ball point pen and thought OH I can lubricate the charger just like as if the vanes were 3 inch wide and 1/2 inch thick gel pens and instead of ink I used grease but I think it would take much experimentation to come up with a grease that was just exactly right and I aint going for that on this one. Still the roller vane idea came about that way as I discarded the grease idea but held to the roller point idea.
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84 2.5L Holley TBI Manual Trans White

[This message has been edited by White 84 SE (edited 01-07-2009).]

quote Originally posted by White 84 SE: What I was thinking was that if the vanes where concave where it touched the rollers and had little nubs such as in a watch wrist band where the face joins the band it would become much like a bearing. Actually bearing pins can be ordered just like that. Since there will not be much pressure on the rollers and the vane will be subject to more centrifigal force than the roller it would naturally glide and keep AND be air leak proof I think more than if they were close but not touching. As for the vanes as they extend they ought to be leak proof if they are lubricated which forms a bit of a seal to air. This Roller Vane idea is my own and I havent seen it on any superchargers so it is frontierish. I was looking at a ball point pen and thought OH I can lubricate the charger just like as if the vanes were 3 inch wide and 1/2 inch thick gel pens but I think it would take much experimentation to come up with a grease that was just right and I aint going for that on this one. Still the roller vane idea came about that way as I discarded the grease idea but held to the roller point idea.

Yeah, that's kind of what I meant with my bicycle fork analogy, yours is certainly a better analogue though. Anyway, what I wonder about though, is yes the ends will be good and sealed, but what about the tops and bottoms of the extended vains? Ideally they should seal up against the case as well, but I just can't think of a good way to make that work.

[This message has been edited by Twilight Fenrir (edited 01-07-2009).]