quote Originally posted by 86fierofun: sheesh. It's not guaranteed to blow up people. The duke is a way better engine than people give it credit for.

True, but not in the area of performance upgrades. The duke was a cheap reliable engine that would do the job as long as you maintained it really really well. But if you want performance the head is terribly weak and the head gaskets will NEVER hold up under boost for very long. The heads warp if you overheat your engine even just once. Boost adds heat and it won't be long before the head warps and BOOM! No more engine. The SD head is nearly TWICE the size of the stock unit. Not only that but the deck height on the SD is .500 in thicker than the Duke for this very reason. Don't even get me started on the tiny little crank or the connecting rods that break on STOCK engines let alone boosted ones.

I admire your spunk but unless someone gave you a parts bin full of freebies and you have a spare engine to put in when the experiment goes wrong, I would find a different solution.

I've overheated my engine, and my heads fine.

The duke has it's weak spots, but it isn't as bad as everyone says.

No point in arguing. I"ll be eager to see how this develops.

dukes are crap engines for performence. they wernt made for stuff like that.
im sure they can hold afew bolt on mods but nothing overkill like boost or spray.
to much for the duke to handle. like i would build a supercharger and use the duke as a prototype and make it for the SD4 engines. im sure they would hold that kind of stuff.
not to trash your ideas or anything.
i think its great. but i think its kinda waste of time to put it on a normal duke engine and know that it will blow up. all that time and effort just to watch the engine blow up.
seems kinda silly.

so if duke and sd4 parts are mostly interchangeable and small block chevy heads fit on an sd4 (according to krp) ,will a sbc head fit on a duke? that would be a real cheap upgrade .junkyards are full of them .

i would think the combustion chamber would be bigger then the dukes making it less compression?
i guess if you got it off like a 305 engine. i think they have 58cc or something. i cant really remember the exact size. tho i dont know the size of a dukes Comb. chamber.

When it comes to the intakes on your charger, would it be advantageous to make it a cold-air intake? Maybe splice it in where the factory intake is. Would keep that problem of the hot air around it down. And, should allow a bit easier design as you have a more defined in/out path. Wouldn't be expensive either, just run a dryer/vacuum tube and there we go :P

Please have a camera aimed on it when you want to really give it to it. I like watching engines blow

quote Originally posted by White 84 SE: Raz... right now Im thinking best to filter after. More like theres not nuff room but there will be a screen...

right on. won't dirt and debris kill the sc over time if it's constantly exposed to raw air? just trying to think with ya

quote Originally posted by Raz50: right on. won't dirt and debris kill the sc over time if it's constantly exposed to raw air? just trying to think with ya

Well, that's another part of what I was asking about a cold-air-intake, it would allow room for an air-filter before the SC.

[QUOTE]Originally posted by Toddster:


. The heads warp if you overheat your engine even just once. Boost adds heat and it won't be long before the head warps and BOOM! No more engine.


not true the iron heads on the duke will survive many overheatings i'm at three and while I did blow the head gasket the heads usually only crack/ warp down near the rockers where the iron is thinner my engine is fine and after I fixed the issue it starts right up and runs fine. and If you had read the entire thread you would realize White 84 SE is only looking for a small HP gain not stupid amounts of power while heat is a factor while it is with all boosted engines may or may not be a big issue for such a small amount of boost

quote Originally posted by wftb: so if duke and sd4 parts are mostly interchangeable and small block chevy heads fit on an sd4 (according to krp) ,will a sbc head fit on a duke? that would be a real cheap upgrade .junkyards are full of them .

The "SD" blocks that KRP makes aren't the same as the original Pontiac castings. When you order one, the bore centers and head bolt/coolant passages/oil passages in the rough cast block will be machined to your head's specifications. I've been to their shop and talked with them about this in depth - fitting an SBC head to the SD block is NOT an easy task and requires a large number of changes not well suited to the original blocks.

FYI chamber size on my old Duke head was measured at ~47cc. When I was running with ported heads they cracked without ever overheating.

Any chance you could just pull the motor off a vacuum cleaner or a leaf-blower to make the small amount of boost you're looking for? :P

um, not to rain on your idea, but that looks like a centrifugal supercharger, flipped 180; with no internal gear box

what if you got a turbocharger. and somehow modify it abit so you can strap on a pullie. block off the exhaust inlet and outlets. would that work as a supercharger?

quote Originally posted by joshh44: what if you got a turbocharger. and somehow modify it abit so you can strap on a pullie. block off the exhaust inlet and outlets. would that work as a supercharger?

Turbochargers operate at a much higher RPM range than most superchargers. You'd have to drive it well above 50K RPM, conservatively. You'd need at least a 10:1 pulley. Turbochargers also have a bearing/rotating assembly setup designed for much different loads than a pulley with belt tension, the bearings/compressor would be lunched in no time.

ohhh ok i didnt think of that part.
makes sence tho.
i thought it was a good idea tho best of luck making the supercharger

I'd play it safe...larger TB, better free flow exhaust, perfornance ignition and leave it at that. A while back there was a guy by the name of Bryson who boosted a Quad Four and he blew a rod through the block. Just imagine what things will be like boosting a much weaker engine.

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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 "

Yeah yeah hey guys I'm just checkin this out. If I like the feel of it and it makes driving a little more fun I will beef up my overhaul. P.S. I'v got a new scribble drawing for a design that has a cold air intake and a traditional impeller. I'll get to posting in a day or so. I just gotta get under the car to check on sizes and places to fit stuff. If I need a step up to get a incy wincy bit over draw Ill just make one with an extree pulley.... no biggie

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84 2.5L Holley TBI Manual Trans White

Here is some advice... take that money you're going to blow on your old 90 hp duke, and buy yourself a car with a supercharger in it already PERIOD

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1986 GT Fiero Owner & Enthusiast
For Fiero updates, visit my site and don't forget visit our google ad sponsors
http://educatorstop15.com/fieropage.htm

quote Originally posted by chrismclubm: Here is some advice... take that money you're going to blow on your old 90 hp duke, and buy yourself a car with a supercharger in it already PERIOD

We've been over this >.> Quit raining on our parade! :P

quote Originally posted by Twilight Fenrir: We've been over this >.> Quit raining on our parade! :P

Yes, please. Some want to see him succeed, some want to see him fail, but we all want to see him try. Urging him in other directions is pointless. Yes, the idea and project is pointless. But in case you didn't read the first post, which we all probably skip when it's longer than a couple pages (at least I usually don't totally read it...) He isn't concerned about the engine, and he isn't concerned with huge gains. This is a brainstorm and proof of concept.
It would be helpful to provide constructive criticism, analogies, suggestions, and factual reasons why it would or would not work. Speculating isn't getting it done, but multiple people doing research at the same time to prove or disprove this idea means that we can ALL learn something. I guarantee you will learn something you were not previously aware of.

Now, we need "Vision 2.0", White 84... I wanna see this drawing!

what if you built your own intake for the supercharger?

or go real crazy and make something kinda like this?

quote Originally posted by joshh44: what if you built your own intake for the supercharger? or go real crazy and make something kinda like this?

Just make sure you are at least 2 miles from the car, behind ballistic shields before you turn the key....

[This message has been edited by Twilight Fenrir (edited 12-20-2008).]

what is the weakest part inside the duke? is it the crank or the rods?
couldnt you get some titanium rods and a custom crank that is properly balenced?
just woundering so the guy doesnt explode the engine on startup

quote Originally posted by joshh44: what is the weakest part inside the duke? is it the crank or the rods? couldnt you get some titanium rods and a custom crank that is properly balenced? just woundering so the guy doesnt explode the engine on startup

the crank and rods are good for 140hp; barring proper fuel and ignition timing; pafft pointed that out in 84 when they made there turbo kits. past that mark is anyones guess and yes theres' none of any turbo kits because poor oil changing by the public and no company want to get sued because "but i bought your kit but you didn't tell me i couldn't boost it more" :P

the rods would either have to be custom because of the width(i think; got to check the books) 0.900id width vs. 0.940sbc
or you could use 301 turbo rods, there good for 12psi at 7.50cr

quote Originally posted by joshh44: what is the weakest part inside the duke? is it the crank or the rods? couldnt you get some titanium rods and a custom crank that is properly balenced? just woundering so the guy doesnt explode the engine on startup

Yes but most on the board fail to accept that. I have yet to hear of a duke crank that has failed. The rods were a bad point as are the pistons. Change them and use an 87-88 crank and it will be fine. If you want to upgrade past that a marine crank will work with some machine work.

quote Originally posted by The_Stickman2: My rods aren't custom and they are better than stock.

ok so what are they from then; because the only one's i've come across on my search that fit are the 301 turbo or the 87-93 id rods.

quote Originally posted by baldlobo: ok so what are they from then; because the only one's i've come across on my search that fit are the 301 turbo or the 87-93 id rods.

Here are the specs of my build.


Ok here are those part numbers I promised.

Comp Cams 52-000-5
260-8/260-8 h114+4
serial# J 4037 03658464155
Valve springs
988-8
1.400 2 spring assembly
lifters
864-8
Pont 151 hyd lifter

Crane Cams
Energizer rocker arms BTW while looking for the box for the part #'s I found said box and low and behold I still
13744-16 have 8 NEW rockers in the box. Anyone wanna make an offer?
Fel-Pro head bolt set
ES72733 future # 21-1117

King Bearings
MB5532AM 010
MS1733 *6689M

Melling oil pump oil pick-up screen
62-CS1
Melling oil pump
M-62CHV

Cloyes Gear
Alloy gear set
Have no idea what the part number was
Just get one as the fiber gear will give up on you when you least want it to.

Badger Pistons "Diamond Turned" Yes I realize I went with a .030 over bore when i have been saying not to. Don't remember why I did. Maybe I needed to in order to use this particular block.
P483-030
Federal Mogul sealed Power( i think these were the piston rings)
E-381X 30

Not sure what rods I used but I believe they were Badger's too.
Sorry no part #

Super Duty Head gasket(cast-iron head)
10031324

Parts I have but were not used in this build

B&B main cap studs
SD-4 engine 10 pcs
10045408

Dynagear
Alloy gear set
221-2525S

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My sites
http://the-stickman.tripod.com

http://www.youtube.com/TheStickman

quote Originally posted by The_Stickman2: Not sure what rods I used but I believe they were Badger's too. Sorry no part #

lol

thanks for the info stickman

if you are still making that custom superchager and would like some real drawings and 3d renderings pm me id love to do it

Yo, white84, I was doing some research, and came across these pages... Grab some hot cocoa and thoroughly read them - there's excellent info in them.

Supercharger Basics
Superchargers A-Z << This is a 3 part discussion, including the history of SCs. Pay special attention to the Paxton VS57 supercharger...

Very nice

Wow that VS resembles my design. I dont think the duke needs a step up gear ensemble nor a clutch. Just a tiny pulley....I hope. I think Ive settled on a design, gonna try to post a pic of the drawing but probably not until Tuesday. Dont have the time right now......wow this thread is getting views! It's gonna be a bit before I pour some aluminum.... like a couple weeks so you know.

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84 2.5L Holley TBI Manual Trans White

quote joshh44:what is the weakest part inside the duke? is it the crank or the rods?...

Actually, the designers achieved an economical balance. The weakness of the rods is equal to the head but slightly weaker than the crank and block.

So if one uses stronger rods, a stronger head, block and crank will be required to handle significant HP improvements.

quote Originally posted by Four_hundred_86: not true the iron heads on the duke will survive many overheatings i'm at three and while I did blow the head gasket the heads usually only crack/ warp down near the rockers where the iron is thinner my engine is fine and after I fixed the issue it starts right up and runs fine. and If you had read the entire thread you would realize White 84 SE is only looking for a small HP gain not stupid amounts of power while heat is a factor while it is with all boosted engines may or may not be a big issue for such a small amount of boost

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.

wow. from the sounds of it. the heads suck on the duke.
is there aftermarket heads for the dukes? stronger?
is the block on the engine fairly weak also?
so lets say you got the strongest stuff for the engine. will the block crack with extra hp?

Smokey Yunick. 250hp from a Duke, intake manifold temps @ 440^o. 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...