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Before you tell me to swap it out just indulge me. I have an 84 iron duke 4speed with i believe 80k original miles. I have already figured out how to get 140hp in the duke with rebuilds or a swap to a 3.0 marine. I want to buy my turbo or supercharger first and run it at low power until i am ready for a rebuild. Id like to know the following: turbo or super and which model will fit my stock tbi duke without blowing it up or eating my gears. I only expect that 7lbs of boost will be the stock crank and rods max for daily driving and the occasional sprint up hills or passing. If there is another alternative or creative suggestion im interested as long as your not telling me to swap my engine. If you have resource sites please link them.
turbo please , u have the car i want to turbo so bad , a duke powered 4cyl is the only f-body i do not own that has a turbo on it. i have 2 v6 turbo cars , and a v8 turbo iroc
us v6 guys in the v6 section can lend plenty of advice to doing a one off turbo kit on it.
the duke is a fairly stout engine, though i will admit i am not familiar with the trans behind that engine 4 speed manual correct?
i have been searching for a duke car for a while though f-bodys in general are very scarce in my area , my last 2 i had to drive out of state to get
for a few hundred bucks u could easily turbo the 4cyl , the cheap avg v6 build is about 800 bucks , the 4cyl motor will cost about half that is what i estimated it at when i started looking for a 4cyl car to do
turbo please , u have the car i want to turbo so bad , a duke powered 4cyl is the only f-body i do not own that has a turbo on it. i have 2 v6 turbo cars , and a v8 turbo iroc
us v6 guys in the v6 section can lend plenty of advice to doing a one off turbo kit on it.
the duke is a fairly stout engine, though i will admit i am not familiar with the trans behind that engine 4 speed manual correct?
i have been searching for a duke car for a while though f-bodys in general are very scarce in my area , my last 2 i had to drive out of state to get
for a few hundred bucks u could easily turbo the 4cyl , the cheap avg v6 build is about 800 bucks , the 4cyl motor will cost about half that is what i estimated it at when i started looking for a 4cyl car to do
If you can't find a duke to build and you have a shell and the money you could just get a new mercruser 3.0. Its pretty much a copy of the duke but its got all SD internals and it turns 140hp stock. You would just have to do a few little modifications. With the SD parts you could boost it with 14lbs probably.
Anyway back to my car. I'm not entirely sure which four speed i have but yes its a four manual. I originally thought it was a sag four but i need to run my vin to be sure. At 98 hp i cry a little when i go up hills but everywhere else its a blast (unless i have to pass a v8 or turbo car. Everyone wants to race me). I'd figure about 110HP would be perfect until i rebuild with SD parts. People say at about 120-150 on stock parts you start gnashing teeth and bending push rods.
Turbo options? A few people suggested that the 301 and 301t turbos would mount up easily to the 151 because its basically half of the 301. (I'm not educated in turbo mechanics so i need a crash course.) I have two years of engineering schooling and I learn quickly which has helped because this is the first car i've turned wrenches on. (I love older cars. Everything is so easy to work on and its built to last.)
If you can't find a duke to build and you have a shell and the money you could just get a new mercruser 3.0. Its pretty much a copy of the duke but its got all SD internals and it turns 140hp stock. You would just have to do a few little modifications. With the SD parts you could boost it with 14lbs probably.
Anyway back to my car. I'm not entirely sure which four speed i have but yes its a four manual. I originally thought it was a sag four but i need to run my vin to be sure. At 98 hp i cry a little when i go up hills but everywhere else its a blast (unless i have to pass a v8 or turbo car. Everyone wants to race me). I'd figure about 110HP would be perfect until i rebuild with SD parts. People say at about 120-150 on stock parts you start gnashing teeth and bending push rods.
Turbo options? A few people suggested that the 301 and 301t turbos would mount up easily to the 151 because its basically half of the 301. (I'm not educated in turbo mechanics so i need a crash course.) I have two years of engineering schooling and I learn quickly which has helped because this is the first car i've turned wrenches on. (I love older cars. Everything is so easy to work on and its built to last.)
If you're only shooting for 110HP right now from 98HP, I'd suggest a new camshaft, port and polish on the head and do some port work on the intake and depending on your exhaust set up now, do the exhaust too and you should have some good gains. Idk where you could get a camshaft for the Duke as I've never searched for one, but I'm sure delta could regrind your camshaft and if you're still looking to turbo even with the work above, just spec your camshaft to work well with a turbo.
one of these would work as well
http://www.ebay.com/itm/T25-T28-hybrid-turbos-oil-cooled-pair-/131564126928?hash=item1ea1d542d0&vxp=mtr
auction is for a pair but if u could snag them cheap u would have a spare
i little t3 off a volvo or one of the t3's off a 2.2L dodge or a t3 off a ford 2.3L would do nicely
just be aware the newer volvos have little gt 15 and 17's on the which are way to small
I went to o'reilly and one of the guys said the 2.2L dodge turbo would run me 300. I was also offered a job working there which in that case could save me a lot. What one would you suggest for the range? I'd like to have 7 on my low end but the ability to push it up to 14 once i'm totally done.
If you're only shooting for 110HP right now from 98HP, I'd suggest a new camshaft, port and polish on the head and do some port work on the intake and depending on your exhaust set up now, do the exhaust too and you should have some good gains. Idk where you could get a camshaft for the Duke as I've never searched for one, but I'm sure delta could regrind your camshaft and if you're still looking to turbo even with the work above, just spec your camshaft to work well with a turbo.
That sounds like a lot of extra time money and work. Is it necessary in order to run low boost? I could rebuild the engine with merc 3.0 parts to hit the 120-140hp mark but that's 600-700 bucks and time i can't afford to have my daily driver down. Maybe a higher performance intake and throttle body would fix the issue and give me the extra power without needing a turbo? I know holly did a TBI that gives you 40% more air and 10% more hp. Then I could do a K&N air intake for 5-10 more hp? Maybe a little ram air kit?
Last edited by InfinityShade; 08-02-2015 at 03:24 AM.
A K04 turbo from a Cobalt SS/TC or Solstice GXP is a good turbo option. There easy to find for $150, used, in the right places, and can support almost 300WHP with near instant spool on a 2.0L engine.
That sounds like a lot of extra time money and work. Is it necessary in order to run low boost? I could rebuild the engine with merc 3.0 parts to hit the 120-140hp mark but that's 600-700 bucks and time i can't afford to have my daily driver down. Maybe a higher performance intake and throttle body would fix the issue and give me the extra power without needing a turbo? I know holly did a TBI that gives you 40% more air and 10% more hp. Then I could do a K&N air intake for 5-10 more hp? Maybe a little ram air kit?
Well whether you went turbo or not, port and polishing the head and doing port work in the intake would help. And you can do it yourself as long as you feel comfortable and have a die grinder.
I believe Delta charges $100 bucks or something around there to regrind your camshaft. It'd be worth it to upgrade your camshaft for a turbo or not.
You can find cat back exhausts cheap used if you look around. Or or you can piece one together or take it to an exhaust shop and have them custom make one.
How long can you allow for this car to go down, since you said this is your daily driver. If you can't afford for it being down long, maybe a good option would be to find another cheap Duke somewhere ether on craigslist or the yard and build that one up while you drive the car, then spend a weekend swapping over.
And do you have access to a welder and know how to weld? Or have a buddy that can? When you do a turbo, you're gonna have to make up a turbo header. You could do a rear mount turbo but you'll need an oil pump then to return the oil.
And most importantly, what's your whole budget for this?
Well whether you went turbo or not, port and polishing the head and doing port work in the intake would help. And you can do it yourself as long as you feel comfortable and have a die grinder.
I believe Delta charges $100 bucks or something around there to regrind your camshaft. It'd be worth it to upgrade your camshaft for a turbo or not.
You can find cat back exhausts cheap used if you look around. Or or you can piece one together or take it to an exhaust shop and have them custom make one.
How long can you allow for this car to go down, since you said this is your daily driver. If you can't afford for it being down long, maybe a good option would be to find another cheap Duke somewhere ether on craigslist or the yard and build that one up while you drive the car, then spend a weekend swapping over.
And do you have access to a welder and know how to weld? Or have a buddy that can? When you do a turbo, you're gonna have to make up a turbo header. You could do a rear mount turbo but you'll need an oil pump then to return the oil.
And most importantly, what's your whole budget for this?
I like to plan ahead so no set dates. As for budget, low but effective. I dont want to go cheap and regret it but i dont need a 3 grand build. So far i can spend 50-100 here and there on replacements thus far so if i were to save i could probably stand to spend 300 a month on parts. But thats at my current job.
This is my research time. I currently only get 1 day off a week which is my window. Im dont intend to do any major modifications until I have everything outlined.
Reground camshaft? How would regringing it benafit over just purchasing a preformance one? I am not too savy in mechanics yet. I dont understand travel on camshafts or crank shafts but i comprehend function. Its the numbers and details im missing. When im looking at camshafts and it says 252 or 260 intake/exhaust and vaulve life .460 and .489 im lost. So i need some education.(larger number=longer exhaust and intake time for higher rpm ranges?)
I need to maintain back pressure when i do the exhaust? If i port match those numbers change right? I currently have a custom exhaust that makes the duke sound more like a v6.
I learned to weld when i was going to school for engineering and could use the engineeting shop if i need custom fabrication. Id have to brush up on my skills though. Im guessing you ask because i need a hole in my exhaust to mount the turbo on? And that brings up the next question i had. Is the turbo mounted to the exhaust manifold or to the cylinder head directly on the exhaust? (I need a referense and somewhere to learn so i dont have to ask common knowledge questions.)
Last edited by InfinityShade; 08-02-2015 at 03:02 PM.
Seen it... not impressed and that has nothing to do with the iron duke lol... read this if you want impressive engineering. Ive been working on a manifold that does this. http://www.legendarycollectorcars.co...clusive-video/
Hence why i'm not impressed... If we are going to innovate we should address the real issues not just repeat the same design and expect something different. Its still a combustion engine using your standard gas delivery system. While i'm glad to see them using the kinetic energy to continuously carry the power its more complex then a rotary and it probably can't run on all fuel formats. What we should be doing is figuring out how to convert our gas so we aren't wasting 75% of it. (No objects are burning themselves, just the gas they emit at a given temperature.)
1 day off? Don't mess with it is my advice short of doing the basics (exhaust, intake tune up) as it is your DD.
In terms of turbos though you have a lot of options due to the lower output you have now. Turbocoupes, DSMs, vehicles mentioned above (be sure you don't get something with an integral manifold.)
I would not do a mechanical blower merely for the fact that the 2.5L is known for a notoriously weak crankshaft stock. Boost is likely pushing it as-is.
I agree, don't mess with it for now, just do little things.
Take that money you were gonna spend for this car, put it in savings till you get another car you can DD or one to work on in your free time. It sucks to hear this but that'll be a better option for you at this time.
I have 3 vehicles, a 2015 Cruze I just got last month, a 1999 Silverado 4.8 4x4 5 speed, and my drivetrain-less 87 Camaro. I don't mind my Camaro being down because I don't need it to get around. It's been a 2 year project atm between getting it running good with the 2.8, having a bad transmission that was complete junk, ripping the drivetrain out, redoing the whole car, and building a Sbc 350 to go in and turboing it. I'd had a lot of change of heart in my plans but now I've have a good direction. Only good thing is I been buying transmissions and then selling them making profit. Had 1 700r4, 1 TH350, and a T5 I was gonna use for some reason till I finally just agreed with myself all I'd do is blow something up in it and ruin a perfectly good WC T-5 and sold it to a guy who was restoring his z28.
Basically a short point I'm saying is, save your money, make a plan, and then start the execution when you have everything covered.
Like I said, only good thing is for me, I've been making a profit on all the transmissions I've bought lol
Ooooo, a boosted Iron duke... I'm another one that thinks that would be a really cool idea.
Everyone likes turbos, but there are some good blowers out there for this, like one of the little Eaton M62's, with the right pulley on it would make some nice power and would probably be less work to make work than a turbo (although I'm not really familiar with the layout of the engine bay in an iron duke 3rd gen, that could change if something is in a weird place...).
Supercharger/turbocharger, either would be cool...
I agree, don't mess with it for now, just do little things
This is my planing stage I am not as familiar with vehicular mechanics as I am other things but through questing and pondering I have been given the information I need for research and planning. I've been hopping around the forum digging up info on all my future plans. I guess everyone has the impression i was going to do these things on the spot. My next real project will probably be weatherstripping lol. Then hopefully the camshaft (push rods and lifters too) and maybe a holly TBI. I really do appreciate the advice. Everyone has been helpful.
there are some good blowers out there for this
I didn't even consider a blower... I like it. The engine in the camaro duke is in line rather then sideways like the firebirds so i could fit a blower easily. A blower would probably be the smarter option and it would solve my problems without major fabrications. Only question left is can my crankshaft handle it? The only crankshaft upgrade I know of is the SD crank from the 3.0l Mercruiser and id have to use the heads from the 3.0 for that. Unless it has the same travel?
This is my planing stage I am not as familiar with vehicular mechanics as I am other things but through questing and pondering I have been given the information I need for research and planning. I've been hopping around the forum digging up info on all my future plans. I guess everyone has the impression i was going to do these things on the spot. My next real project will probably be weatherstripping lol. Then hopefully the camshaft (push rods and lifters too) and maybe a holly TBI. I really do appreciate the advice. Everyone has been helpful.
I didn't even consider a blower... I like it. The engine in the camaro duke is in line rather then sideways like the firebirds so i could fit a blower easily. A blower would probably be the smarter option and it would solve my problems without major fabrications. Only question left is can my crankshaft handle it? The only crankshaft upgrade I know of is the SD crank from the 3.0l Mercruiser and id have to use the heads from the 3.0 for that. Unless it has the same travel?
Glad we can help.
And as far as I know, there are no blowers that will fit an Iron Duke. It'd be a complete custom intake fabrication job, which would be tig welding and machine work. Someone can correct me if I'm wrong on this but as far as I know, nothing stock or aftermarket will be a drop and bolt deal.
The other option would be a custom bracket to hold an Eaton style supercharger off to the side and make an adapter plate to tube to route the boost to the intake. This has been done on other engines, you can google it and find a few threads.
As far as the crank, I've heard that the crank was very weak due to it's design and balance. So you may be treading on fire. Another issue I've heard is that the block is very thin walled. I've never had an iron duke, nor tore one apart to see, so do some research and see.
And as far as I know, there are no blowers that will fit an Iron Duke. It'd be a complete custom intake fabrication job, which would be tig welding and machine work. Someone can correct me if I'm wrong on this but as far as I know, nothing stock or aftermarket will be a drop and bolt deal.
The other option would be a custom bracket to hold an Eaton style supercharger off to the side and make an adapter plate to tube to route the boost to the intake. This has been done on other engines, you can google it and find a few threads.
As far as the crank, I've heard that the crank was very weak due to it's design and balance. So you may be treading on fire. Another issue I've heard is that the block is very thin walled. I've never had an iron duke, nor tore one apart to see, so do some research and see.
Good luck with your future build
Ok, I have friends and family advising me as well. I think i can handle a custom bracket but it sounds like ill still need a new crank. I plan on purchasing alldata diy. It should have the specs i need to continue. It might be easier to just find an intake manafold that fits my needs? Ill do some digging.
If you decide to go supercharger, this type of M62 would probably be your best bet for a remote-mounted supercharger such as Xter suggested:
http://www.ebay.com/itm/97-98-99-00-MERCEDES-SLK230-TURBO-SUPERCHARGER-1110900380/261792407438?_trksid=p2047675.c100010.m2109&_trkparms=aid%3D333008%26algo%3DRIC.MBE%26ao%3D1%26asc%3D29979%26meid%3Def87002feb7b44689f6d382aec9caacf%26pid%3D100010%26rk%3D3%26rkt%3D15%26sd%3D181817580544
You might be able to find a unit cheaper from a junkyard or Car-Part.com.
The amount of "strain" placed on the crankshaft by the supercharger will be directly proportional to how much boost you produce. Less boost, less strain placed on the crankshaft. I still don't know if the Iron Duke crankshaft could take low amounts of boost, though. Not my type of engine, personally.
I've used Toyota ct26 turbos. Very good reliable turbo. They make good hp and there is alot of upgrades. Easy to package and mount. Cheap. Parts for it everywhere.
You can also use a blower off a 3.8 thunderbird and mount it on the side the way ford did it. Make a custom bracket to mount it and use the stock discharge plenum plumbed to your throttle body/carb.
You would have to arrange the pulleys to Line up with the stock pulley system
Efi. Going with a MS system would prolly b most economical and easy to tune. If u wanted to go injected.
a small m62 wouldnt load the crankshaft all that much , what u need is something that will make its power in the midrange. a bunch of boost down low will hurt the crank shaft , and over reving it will also do it
I have a feeling that I'm going to be at odds with a lot of people here, but if this were my car I would stick to modest , easily removable bolt ons and leave it at that. Chevy made very few of these cars, and most of those little iron dukes have been scrapped by now.
If you really want something boosted, why not swap in a GM 3800 with a stock Eaton supercharger? Those things have nads, are bulletproof, and go for real cheap (at least around here).
If you're hell bent on the 4cyl configuration, then you could buy a mercruiser engine and swap all the compatable bolts ons over. But I would hold onto a lot of the stock parts. That car will probably be with more than mine someday.
I have a feeling that I'm going to be at odds with a lot of people here, but if this were my car I would stick to modest , easily removable bolt ons and leave it at that. Chevy made very few of these cars, and most of those little iron dukes have been scrapped by now.
If you really want something boosted, why not swap in a GM 3800 with a stock Eaton supercharger? Those things have nads, are bulletproof, and go for real cheap (at least around here).
If you're hell bent on the 4cyl configuration, then you could buy a mercruiser engine and swap all the compatable bolts ons over. But I would hold onto a lot of the stock parts. That car will probably be with more than mine someday.
I've considered this and intend to keep the engine in a condition that i can reverse in the case its value is increased. However i'm looking for the ability to get up a hill... The iron duke wont lose any value even if it becomes collectible if it has been upgraded without major modification. It will probably be more desirable since it will be closer to the rare firebird engines. Speaking of which my co workers father has a pontiac fiero with the race engine. I want to see it!
a small m62 wouldnt load the crankshaft all that much , what u need is something that will make its power in the midrange. a bunch of boost down low will hurt the crank shaft , and over reving it will also do it
How do you tune a supercharger if its on a belt driven? X belt RPM = Engine RPM = Boost on? Can i set the curve to 1.5-2k rmp to 4k or is it once its on its on and i have to set a limit on the max? Is that why a turbo is what you originally suggested? (sorry im vary inquisitive.)
Maybe I was wrong before, but I would assume that most modifications you are looking at would lower the value of the engine. It sounds weird, I know, but people like all the original stuff more than the high performance pieces.
I love turbochargers and all other superchargers, but they wear your engine out a bit more quickly. When companies test new engine designs, they often turbo them to give a good idea of how long they will last for the same reason.
I think that before we get too far into this though, you should really think about what this car is to you. Make a list of the most important things you'd like from this engine (fuel economy, inspection legality, smiles per gallon, standing quarter mile times, learning new things, etc) and people more knowledgeable than I will help you out.
To me, it sounds like you are really limited by that 4 speed transmission, which was probably aimed at improving gas mileage from its debut in '84. Do you have trouble managing highway speeds? If not, I would consider throwing a big old rear axle from a truck in there. I put one on my 305 t-5 when I got it. That made a really big difference, as did the disc breaks that were also part of the deal. However, i have little expertise with the duke, and others will do better helping you pick a final drive. It's a great entry level upgrade, and it teaches you about transmissions.
Just my 2 cents
How do you tune a supercharger if its on a belt driven? X belt RPM = Engine RPM = Boost on? Can i set the curve to 1.5-2k rmp to 4k or is it once its on its on and i have to set a limit on the max? Is that why a turbo is what you originally suggested? (sorry im vary inquisitive.)
You can swap pulley's. The smaller the pulley, the faster the supercharger rotors spin, the more boost it makes.
Nice, I love how when I say something on here it seems like someone repeats what I said like 2 posts down and then a bunch of people talk abut how he has a good idea.
Originally Posted by InfinityShade
I didn't even consider a blower... I like it. The engine in the camaro duke is in line rather then sideways like the firebirds so i could fit a blower easily. A blower would probably be the smarter option and it would solve my problems without major fabrications. Only question left is can my crankshaft handle it? The only crankshaft upgrade I know of is the SD crank from the 3.0l Mercruiser and id have to use the heads from the 3.0 for that. Unless it has the same travel?
Originally Posted by project89
a small m62 wouldnt load the crankshaft all that much , what u need is something that will make its power in the midrange. a bunch of boost down low will hurt the crank shaft , and over reving it will also do it
Originally Posted by InfinityShade
How do you tune a supercharger if its on a belt driven? X belt RPM = Engine RPM = Boost on? Can i set the curve to 1.5-2k rmp to 4k or is it once its on its on and i have to set a limit on the max? Is that why a turbo is what you originally suggested? (sorry im vary inquisitive.)
The load on the crank would be something on the order of 15-30hp over what you'd see with a similar hp turbo setup. Turbos can hit harder or softer depending on sizing, so that's a wash. With a proper bypass at cruise it will likely be something more on the order of 1/3hp (even some of the bigger ones done right will be <2hp)
Tuning with a positive displacement, screw or lobe type blower is all about getting the pulley sizes to spin it up fast enough to move the air that you need at the lowest engine rpm that you need it. Once you get there you can fine tune the power curve with engine tuning (timing is the easiest and fastest) to keep you out of detonation and breaking other parts.
I've posted similar pictures dozens of times on this site and others, this is my brother's 302 ford which originally had a M90 off of a t-bird super coupe on it, bolted up to a bracket like an accessory. The M90 was pretty heavily modified to increase flow and the car was actually decently fast (10.9's in a 4 door ford):
Here is me machining an M112 off of an Aston Martin to replace the M90:
Nice, I love how when I say something on here it seems like someone repeats what I said like 2 posts down and then a bunch of people talk abut how he has a good idea...
Haha, after all these years, are you really surprised they would do that...?
That's sick. I think for now Ill take the suggestion of doing the exhaust and intake. If i can get what i want out of the exhaust and TBI upgrades i want to do a turbo or supercharger may not be necessary but a turbo sure would be nice for my top end. (4th is the only gear that lacks)
Should I mosey over to the exhaust section or do you guys have suggestions on specifics here? I spoke with my father today and he said headers would help release the individual ports pressure and provide me with a nice boost without sacrificing my MPG. which is really what i want at this point. power but mpg balance.
Haha, after all these years, are you really surprised they would do that...?
You're making me feel old...
Maybe I'm crazy or cocky but for some reason I keep expecting people to start paying attention.
Originally Posted by DIGGLER
wow thats alot of work getting that m90 in there. kudos for that.
Not really, the M90 was a simpler setup externally because the case is smaller, the M112 (in both pics) was a little bit more serious because of the bigger case and my brother wanted to get the TB on the back of the case, I had to machine the heck out of the Aston Martin mounts to get it to clear the strut tower (he refused to cut it) and a few other good bits.
There was a bunch of work done to make the M90 work but that was internal to the blower to get more flow out of it. Do the math and figure out how much airflow it takes to make a 4 door, ford LTD go 10.9 at almost 120mph (that's what it ran with the M90) and you'll realize that thing was really huffing.
He doesn't need nearly the airflow on this thing. I'm betting an M62 turning 1/2 - 3/4 the rpm that we spun the M90 would be enough to be really entertaining on that thing, and a little bit more would likely launch the crank through the oil pan. The compressor maps on those things are pretty simple you can almost literally go "I want x hp and my engine powerband is y" and use that to compute your pulley ratio. That and they breath from down low so when you put your foot in it, besides the sound you really can't tell the difference between it and just doubling (or whatever) the cubes under the hood. The torque curve on the M90/5.0 ford setup literally got fat around 2000rpm and stayed pretty flat till he shifted it, it was a lot like driving a big inch big block when you put your foot in it.
Both are MUCH less work that getting a turbo on a car if you can figure out the packaging.
Originally Posted by InfinityShade
That's sick. I think for now Ill take the suggestion of doing the exhaust and intake. If i can get what i want out of the exhaust and TBI upgrades i want to do a turbo or supercharger may not be necessary but a turbo sure would be nice for my top end. (4th is the only gear that lacks)
The nice thing about the supercharger setup like that is that unless you do something weird with the intake or exhaust packaging, those upgrades will work with the supercharger, where you'd typically have to ditch them and redo with a turbo.
Should I mosey over to the exhaust section or do you guys have suggestions on specifics here? I spoke with my father today and he said headers would help release the individual ports pressure and provide me with a nice boost without sacrificing my MPG. which is really what i want at this point. power but mpg balance.
Honestly, the iron duke is weird enough that I don't think that you'd have much better luck anywhere.
I don't know what is available headers wise, but as long as they're reasonably sized (the iron duke is a 2.5, so I'd think that something with 1-5/8" primaries would be about optimum) they would be a win/win, you'd get better power and MPG, not hurt either. Long tubes if available will get you more midrange/low and mpg and not hurt the top end power also.
Cat back wise... well you have half the engine that the v-8 guys do, so any decent cat back that you want would work fine. If you want something quiet then any of the V8 car's stock exhaust adapted to it would work great (honestly you'll have problems finding a stock 3rd gen exhaust, but 4th gen stuff is all stainless, is the same layout and flows well, I went 11's through the stock exhaust on my '97 WS6, and had the intermediate pipe cut and flanged so I could take the back half off the car at the track and it never showed an improvement in times). Otherwise, pick the sound you like and get whatever cat back you want. I'm betting that all of them will need some minor changes to connect up, but nothing that anyone that can work a welder (or likely some bends and clamps) couldn't work out.
Intake... well again, I have no idea what's available. I believe that they used the same TBI as the crossfire cars but only one instead 2 of the TB's, and those respond really well to injector tower spacers, more fuel pressure (factory 9-12psi, the crossfire and TBI cars tend to run best around 13, I've owned a crossfire TA and a TBI truck), TB spacers, and if you go that far, boring to 2" or so (there's a plug that will drop out of the bore when you do it, but I've just tapped them and then threaded a piece of aluminum rod, coated it in epoxy and threaded in in there, the plug is used to balance the TB's when they were installed in pairs, you don't need it at all, so just plugged is all you need to do.
Last edited by 83 Crossfire TA; 08-06-2015 at 01:34 AM.
here is it bored to, I think it was 2.1" (I posted all the info about this here years ago if you care to go searching) and a matching throttle body spacer (wood to keep the heat out, soaked in aircraft dope to keep the gas from messing it up)
Here you can see the throttle bodies installed with injector tower spacers that I made, the TB spacers, and you can see the front throttle body (the one closer to us in the pic) I drilled the fuel passage across the top to thread in a schrader valve so you could just thread in a fuel pressure gauge to it. I modified the fuel pressure regulator in the rear one to be adjustable. I did all this way back when before I had any machine tools. I rigged a makeshift boring head on a drill press to bore the throttle bodies, cut and fitted the throttle plates by hand... I've even bored throttle bodies and mas air sensors using a hand drill way back when.
I have loads of other stuff (no idea if in the original threads I posted the info about doing all this if the pics still work but I'm sure I could find them if they don't).
Last edited by 83 Crossfire TA; 08-06-2015 at 01:51 AM.
I'm pretty sure this thread is dead, and it may have already been mentioned, but the Mercruiser and the Iron Duke have different Bell housing patterns.
Someone correct me if I'm wrong, but I believe that the Mercruiser uses the v8 Bellhousing. That might mean that you could use it with a v8 t-5.
That extra gear could give you that extra "umph" you're looking for, while still allowing you to retain decent miles per gallon, especially with a big old overdrive.
The Mercruiser comes with a hydraulic roller cam as well, I believe. I have no clue as to whether or not any Iron Duke's did. While the original cam in the Mercruiser will most likely not be well suited for the street, a well chosen hydraulic roller cam will probably net you a little gas mileage and power.
If you do eventually choose to swap, see if you can sell the original transmission on the fiero forum, or some similar place. It may be worth more to them. I would be loathe to part with it though.
As for the intake and headers, check out what was on the TechIV racing engine if you haven't already. Those things were quick.
Keep us posted. This is one of those engines that gets no respect, but that we all secretly love.
I'm pretty sure this thread is dead, and it may have already been mentioned, but the Mercruiser and the Iron Duke have different Bell housing patterns.
Someone correct me if I'm wrong, but I believe that the Mercruiser uses the v8 Bellhousing. That might mean that you could use it with a v8 t-5.
That extra gear could give you that extra "umph" you're looking for, while still allowing you to retain decent miles per gallon, especially with a big old overdrive.
The Mercruiser comes with a hydraulic roller cam as well, I believe. I have no clue as to whether or not any Iron Duke's did. While the original cam in the Mercruiser will most likely not be well suited for the street, a well chosen hydraulic roller cam will probably net you a little gas mileage and power.
If you do eventually choose to swap, see if you can sell the original transmission on the fiero forum, or some similar place. It may be worth more to them. I would be loathe to part with it though.
As for the intake and headers, check out what was on the TechIV racing engine if you haven't already. Those things were quick.
Keep us posted. This is one of those engines that gets no respect, but that we all secretly love.
Thanks, yeah ive found everything i need but compatable heads and ive considered several builds. Id like to keep the 4 speed and make her into a 85mph sprinter. I think with 130-150 hp the 4 speed will do nice.
I need to figure out if the merc heads and crank will work with the 84 block. I dont see an oil pump gear on the merc crank either so im guessing i have to go external? Id like some options that dont require lots of mechine work so id really like to find another crank and head option.
Once you reach 150+ hp you have to up you radiator and get your oil cycle sped up to prevent flexing. Or so ive read and been informed. I can get 130 with headers, emissions removal and ignition upgrades. 400 bucks later ill be happy enough until i decide to do more. By then i should have a second car and work space to build this monster my way.
Id like to wait on the cam until i figure out heads and crank.
Hmm, well I'm way out of my league here. Maybe someone will chime in.
The crank and heads probably aren't compatible because they are very different engines, at least from my understanding. The Merc is based off the old Chevy II in line engines, while the Pontiac is it's own thing. Those merc engines make 140hp stock, which is why they're called the 140. They're also heavy duty to start. It just sounds like a better place to begin.
If the duke is what you are set on, they used to make a crate TechIV racing engine. They're really really expensive.
I don't know how strong that tranny is, so I can't speak to that. Those fiero guys put some power behind them, they would know. Maybe I'm just a show off who likes to shift a lot, but I have trouble believing more gears would ever be a bad thing.
A lot of people swap northstar v8 engines into their fiero's because they have the same bellhousing pattern and mounts. The issue in the fiero is usually fitment. Your problem would probably be that it's a transverse setup stock. I would look into that though. They make decent power, and the cars they're in tend to go for really cheap, like the Olsmobile aurora. Maybe you can ask the fiero guys, I have no experience in that department.
You would want to take as many parts as you could from the doner, like the radiator and fuel pump and stuff. That way you could be sure everything is compatible.
To be honest, if this is your daily driver, I would leave it pretty much as is, and buy a project car to build. Shoot, you could even snag a roller from here or craigslist and build that. I'd look for a 5-speed car with a wrecked 305 in it. That would probably be the closest to a drop in swap you could get. Then most of the miscellaneous parts could swap over too.
It's your world boss, it's whatever you want to do. However, we are quickly reaching the point where people usually start saying that the traditional sbc v8 build will be cheaper power. Before you spend any money on it, make sure the unique aspect of the build is worth it to you.
It's a cool car already. You might be able to trade someone for their v8, if you find a collector. I wouldn't touch it though, it sounds like it's been good to you.
Hmm, well I'm way out of my league here. Maybe someone will chime in.
The crank and heads probably aren't compatible because they are very different engines, at least from my understanding. The Merc is based off the old Chevy II in line engines, while the Pontiac is it's own thing. Those merc engines make 140hp stock, which is why they're called the 140. They're also heavy duty to start. It just sounds like a better place to begin.
If the duke is what you are set on, they used to make a crate TechIV racing engine. They're really really expensive.
I don't know how strong that tranny is, so I can't speak to that. Those fiero guys put some power behind them, they would know. Maybe I'm just a show off who likes to shift a lot, but I have trouble believing more gears would ever be a bad thing.
A lot of people swap northstar v8 engines into their fiero's because they have the same bellhousing pattern and mounts. The issue in the fiero is usually fitment. Your problem would probably be that it's a transverse setup stock. I would look into that though. They make decent power, and the cars they're in tend to go for really cheap, like the Olsmobile aurora. Maybe you can ask the fiero guys, I have no experience in that department.
You would want to take as many parts as you could from the doner, like the radiator and fuel pump and stuff. That way you could be sure everything is compatible.
To be honest, if this is your daily driver, I would leave it pretty much as is, and buy a project car to build. Shoot, you could even snag a roller from here or craigslist and build that. I'd look for a 5-speed car with a wrecked 305 in it. That would probably be the closest to a drop in swap you could get. Then most of the miscellaneous parts could swap over too.
It's your world boss, it's whatever you want to do. However, we are quickly reaching the point where people usually start saying that the traditional sbc v8 build will be cheaper power. Before you spend any money on it, make sure the unique aspect of the build is worth it to you.
It's a cool car already. You might be able to trade someone for their v8, if you find a collector. I wouldn't touch it though, it sounds like it's been good to you.
So now you might see the picture i am painting and for less than you'd expect. The only thing i didn't find was people using larger radiators and oil pumps / bigger lines. Once the crank isn't an issue anymore heat becomes your enemy because of the block flex. I'd expect a mid range build for a balance of power and daily driving wouldn't require me to even touch the crank but i'd like to keep my future options open since i want this car for life.
I'm looking at it now. I think the engine that he is making reference to is the earlier Iron Duke, which has the same bolt pattern as the V8. It's the Chevy 153, where we're talking about the Pontiac 151. Both were called the Iron Duke.
Honestly, I have no clue. Can you just get under the car and read the tag on the transmission? It would help us figure out what's under there.
I'm looking at it now. I think the engine that he is making reference to is the earlier Iron Duke, which has the same bolt pattern as the V8. It's the Chevy 153, where we're talking about the Pontiac 151. Both were called the Iron Duke.
Honestly, I have no clue. Can you just get under the car and read the tag on the transmission? It would help us figure out what's under there.
(no slip, i did the clutch and its not there) I know my rear is 3.42. I know the links are external and on the driver side. I looked up some pictures of the T4 and Sag and it looks like a sag to me. My friend who is a mechanic (certified) said he thought it was a sag as well.
Last edited by InfinityShade; 08-17-2015 at 12:43 AM.
Well, I never thought I'd be happy to see a Saginaw, but this might be that day. There should be a number cast into the side of the Bell housing. There also is probably more help to be found under the transmission section of this forum.
Haha, I didn't realize Alex is your brother. His thread is the only thing that keeps me checking back at the corral.
LOL, makes me wonder if I know who you are...
Honestly, he's gotten a little weird about other people being involved in the thing, machining the M112 is one of the last things I've done on that setup. I think he's blown the thing up 2 or 3 times since then and hasn't told anyone (I haven't been reading his thread on the corral for a while, so I don't know what he's posted there). The funny thing was that the last time he blew it up he didn't tell me and didn't know that I was contracting some work to the machine shop he took the pieces to and I found out that he blew it up again when I was up there and his cylinder heads were on the pile of parts that needed work ("Hey, why's my last name on these heads?" )
07-30-2015, 10:03 PM
I am not as familiar with vehicular mechanics as I am other things but through questing and pondering I have been given the information I need for research and planning. I've been hopping around the forum digging up info on all my future plans. I guess everyone has the impression i was going to do these things on the spot. My next real project will probably be weatherstripping lol. Then hopefully the camshaft (push rods and lifters too) and maybe a holly TBI. I really do appreciate the advice. Everyone has been helpful. 
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