The way it looks the first one (which is almost no different then factory) is gonna be the best. You can still get a k&n drop in with the factory intake that actually pulls air from the outside then hot air that's in the engine compartment.
But what would make a bigger/better difference? For those Iron Duke lovers of course...
The stock CAI system is MORE than adequate for the Duke and the V6. If you want a bit more pep go with a larger throttle body and a non restrictive exhaust system. You might even be able to find a set of headers if you do a search.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The reason everyone is advising you to save your money is because a CAI system only improves performance in one of two cases:
1. the stock air intake sucks air from the hot engine compartment; and/or
2. the stock intake ducting is the most restrictive component in the air flow.
The thing is, the stock Fiero air intake system is already a cold air intake (CAI) system, and the duct wrok isn't the most restrictive part of the intake. On the other hand, if you really want something to dress up your engine bay as a Xmas present, then go for the one that you like best.
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07:38 PM
FirstDrCar Member
Posts: 718 From: Buffalo, NY, USA Registered: Feb 2010
The stock CAI system is MORE than adequate for the Duke and the V6. If you want a bit more pep go with a larger throttle body and a non restrictive exhaust system. You might even be able to find a set of headers if you do a search.
quote
Originally posted by Bloozberry:
The reason everyone is advising you to save your money is because a CAI system only improves performance in one of two cases:
1. the stock air intake sucks air from the hot engine compartment; and/or
2. the stock intake ducting is the most restrictive component in the air flow.
The thing is, the stock Fiero air intake system is already a cold air intake (CAI) system, and the duct wrok isn't the most restrictive part of the intake. On the other hand, if you really want something to dress up your engine bay as a Xmas present, then go for the one that you like best.
I currently have installed the Holley larger bore TBI and Holley intake manifold to complement.
I can understand your frustration, but no one can answer your question with any certainty for several reasons:
1. no one knows how much of an effect the other modifications you're planning on doing to your engine will have on increasing the amount of air flow through your engine, if any;
2. neither manufacturer of the intake systems you've asked about has posted any airflow data for their filter systems; and
3. no one knows what the stock Fiero 4 cylinder air filter assembly is capable of flowing to use as a comparison.
An engine is basically just an air pump so if you don't know how much air it's sucking, nor how much the intake system will allow, nor how much the exhaust will allow, you can't say anything about the performance gains except what's already been said.
[This message has been edited by Bloozberry (edited 12-10-2011).]
I'm really not trying to down your decisions, merely telling you helpful advice that myself and others have learned from experience. The words "Duke" and "Performance" do not go together. Unless you have a Super Duty 4, you honestly are wasting money trying to get more performance out of a Duke, because there really isn't much to be had. The Duke was designed and built to be purely an economical engine. In today's standards it's pretty prehistoric, 92hp out of 2.5L, all cast Iron (it's only 50lbs less then the 2.8 FYI), Throttle Body injection, etc. This is why others go the engine swap route for performance. There are even swaps like the ecotech that when set up properly will give incredible gas mileage plus more power then the 2.8.
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12:38 AM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
I'm really not trying to down your decisions, merely telling you helpful advice that myself and others have learned from experience. The words "Duke" and "Performance" do not go together. Unless you have a Super Duty 4, you honestly are wasting money trying to get more performance out of a Duke, because there really isn't much to be had. The Duke was designed and built to be purely an economical engine. In today's standards it's pretty prehistoric, 92hp out of 2.5L, all cast Iron (it's only 50lbs less then the 2.8 FYI), Throttle Body injection, etc. This is why others go the engine swap route for performance. There are even swaps like the ecotech that when set up properly will give incredible gas mileage plus more power then the 2.8.
This.
FirstDrCar, the Duke wasn't designed for performance. If you start trying to improve it, you're going to want to wring it out from time to time, right? Buzz a Duke too high and you're next post will be about how to change the engine. It's a good economy engine. Keep it tuned and in good condition. Add some of the performance parts if you want, but I seriously doubt you'll notice any difference other than maybe a little bit different sound. Going from 92 to 120 HP is a 30% increase. That's a BIG jump in power, and you're not likely to get that with simple bolt ons and not sacrifice reliability on a stock engine. And even if you manage to get that much out of it, you're still about 20HP down on a stock 2.8 V6.
Figure up what you'd like to do and add up the total costs. You may find you can get a much better return on your investment by spending the money on something else.
First I want to tell you where there is a will there is a way. We previuosly had an 85 Fiero with an Iron Duke. From statements above performance and Duke do not go together,but here is what we had. At 100.000 miles the motor was rebuilt and bored 40 over we added roller rockers with a performance can shaft and a large bore throttle body and manifold from Holley. The manifold was ported for better air flow. Some above have told you things like a less restrictive cat and cat back system on the exhaust which will help but your motor works both ways you have to get air flow in and then get it removed! We did the exhaust system thing and added bigger diameter pipes when we did the muffler and the cat. As for air flow the stock system has a restrictive plate that keeps water out so we added a cold Ram air system to the car the ram air was added using a holley ram air scoop on the side of the car along with a non restrictive cold air intake pipe that came direct from the outside scoop. The filter was still in the stock location using a K&N unit that did not restrict much air. The result was we had a faster than stock running duke but the down fall was poor gas mileage out of a four cylinder motor. I can tell you that we ran the car several years at Watkins Glen and were able to run right along with the 6 cylinder Fieros. Pulling the hills was not problem and we could hit 110 on the straight on the track. To me this motor was a good investment that still runs strong today. You can ad performance parts to the Duke but they have their limitations if you go too far you will blown them up. I would diffinately ad a true cold air intake with a side ram air scoop. Don't let others stop you from trying things your self. One word I can tell you is that the header for the duke to me is not a good investment unless it was made by Hooker, just port your stock manifold that will be enough
------------------ 1984 Indy Pace Car\1988 Formula Custom President of Maryland Fiero Owners Club MFOC NYFOC Member
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08:37 AM
hyperv6 Member
Posts: 6002 From: Clinton, OH, USA Registered: Mar 2003
GM engineer Herb Adams did a show room stock racer in 1985 and found the factory system as good as any Cold Air intake that could be fit in.
The factory intake he showed on the dyno was very good. Also if you are not running a Mass Air Flow system on you engine there is nothing much to gain as the engine will not adjust to more air or highter flows. The factory V6 is a closed loop system that Pontiac thought worked better and was more consistant. THis is true but the Mass Flow system is more adaptable and will react to changed. The Chevy 2.8 has this system.
Even at best with a good system on the car and bolting a new intake on even with mass air may yeild only 9 HP. That is what we see with cars and KNN intakes if they already have a good system. Some cars with poor intakes may see 15 HP with a KNN.
In either case there even with a gain it will be small.
The factory flows a lot better than most people think. A KNN in the stock can will do really well.
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08:51 AM
cam-a-lot Member
Posts: 2133 From: Barrie- Ontario, Canada Registered: Oct 2010
First I want to tell you where there is a will there is a way. We previuosly had an 85 Fiero with an Iron Duke. From statements above performance and Duke do not go together,but here is what we had. At 100.000 miles the motor was rebuilt and bored 40 over we added roller rockers with a performance can shaft and a large bore throttle body and manifold from Holley. The manifold was ported for better air flow. Some above have told you things like a less restrictive cat and cat back system on the exhaust which will help but your motor works both ways you have to get air flow in and then get it removed! We did the exhaust system thing and added bigger diameter pipes when we did the muffler and the cat. As for air flow the stock system has a restrictive plate that keeps water out so we added a cold Ram air system to the car the ram air was added using a holley ram air scoop on the side of the car along with a non restrictive cold air intake pipe that came direct from the outside scoop. The filter was still in the stock location using a K&N unit that did not restrict much air. The result was we had a faster than stock running duke but the down fall was poor gas mileage out of a four cylinder motor. I can tell you that we ran the car several years at Watkins Glen and were able to run right along with the 6 cylinder Fieros. Pulling the hills was not problem and we could hit 110 on the straight on the track. To me this motor was a good investment that still runs strong today. You can ad performance parts to the Duke but they have their limitations if you go too far you will blown them up. I would diffinately ad a true cold air intake with a side ram air scoop. Don't let others stop you from trying things your self. One word I can tell you is that the header for the duke to me is not a good investment unless it was made by Hooker, just port your stock manifold that will be enough
Any engine can gain some improvement if one pours enough money into it. However, it is still a complete waste of money. The duke is a 1970's economy car engine and it is a complete dog. Unless it is an SD motor, my wife's Toyota Sienna can hook up an 18 ft boat, load 3 kids and their gear into the van, turn on the A/C, and still blow away any Duke powered car in 0-60 and quarter mile.
How much time and money is it to pull a duke, bore it out, replace camshafts, rockers, etc??
As a comparison, I bought a complete 2007 Series III SC for $1200 with less than 30,000 miles on it.
Performance parts for the duke may make it look pretty or let the owner "feel" that they are gaining performance, but it is still just applying lipstick to a pig. If you like 4 cyl performance and want to rebuild an engine, the 2.0 turbo or Ecotec are great options to invest money in.
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09:10 AM
Mark A. Klein Member
Posts: 608 From: Pleasantville IA Registered: Aug 2002
Hey nay sayers.... I have had quite a few Fiero's.... I had one SPECIAL duke. No it was not anything special, more of a get lucky and get a good one. I had a 1986 Gold Sport coupe that just ran circles around all other Dukes and most stock V-6's! If you want to love your duke, that's great! Dukes like ALL internal combustion engines respond to the same Hot rodding techniques as the others. So, If you get the chance - Balance the entire motor!. This is probably the greatest reason some motors run soooo much better than others. The port, polish and take the time to tune, ie. cam timing, ignition timing, etc... Be happy they can be snappy if you get a good one. Gas mileage improves, and they will actually last longer... That one went 240,000 miles completely stock, no repairs! Please remember that it was just luck getting a good one....
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10:07 AM
PFF
System Bot
FirstDrCar Member
Posts: 718 From: Buffalo, NY, USA Registered: Feb 2010
I appreciate the discussion on this thread. All opinions are certainly welcomed, so thank you.
It gives me a good feeling inside to be driving a 1984 Fiero with the original 2.5L duke. The first year of the car with the first engine. Yes it is probably the worst year for the car, the worst duke of all the fiero years... sure.
But I would like to keep my duke engine in the car. I do not want to do an engine swap, I do not want to do serious body modification. I want to keep my car mainly stock with "tasteful" upgrades, whether they involve interior, exterior, or engine wise.
So I am looking to "tastefully" upgrade my duke, not replace it. I would like the 84 Iron Duke to run as good as it possibly could. So when I say performance/HP gains, I know I will never match an engine swap or even the Fiero V6, but I would still like to upgrade my Duke.
From what I am gaining from this discussion, is I should just go with Rodney's True CAI product instead of the High Performance Air Intake from TLG. Is this correct?
quote
Originally posted by amflyer:
You can ad performance parts to the Duke but they have their limitations if you go too far you will blown them up. I would diffinately ad a true cold air intake with a side ram air scoop. Don't let others stop you from trying things your self. One word I can tell you is that the header for the duke to me is not a good investment unless it was made by Hooker, just port your stock manifold that will be enough
Does Hooker or another name brand company make a header for the 84 duke?
I appreciate the discussion on this thread. All opinions are certainly welcomed, so thank you.
It gives me a good feeling inside to be driving a 1984 Fiero with the original 2.5L duke. The first year of the car with the first engine. Yes it is probably the worst year for the car, the worst duke of all the fiero years... sure.
But I would like to keep my duke engine in the car. I do not want to do an engine swap, I do not want to do serious body modification. I want to keep my car mainly stock with "tasteful" upgrades, whether they involve interior, exterior, or engine wise.
So I am looking to "tastefully" upgrade my duke, not replace it. I would like the 84 Iron Duke to run as good as it possibly could. So when I say performance/HP gains, I know I will never match an engine swap or even the Fiero V6, but I would still like to upgrade my Duke.
From what I am gaining from this discussion, is I should just go with Rodney's True CAI product instead of the High Performance Air Intake from TLG. Is this correct?
Does Hooker or another name brand company make a header for the 84 duke?
Thanks again for everyone's input
Yea I would buy Rodney's intake kit instead of the TLG intake, because as you may or may not know, the TLG intake is actually the opposite of a CAI..it draws in the hot air from the engine bay instead of outside the engine bay like the factory setup.
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01:47 PM
Rodney Member
Posts: 4715 From: Caledonia, WI USA Registered: Feb 2000
GM engineer Herb Adams did a show room stock racer in 1985 and found the factory system as good as any Cold Air intake that could be fit in.
The only argument is how did he do this test? Did he just remove the intake tube from the throttle body or air cleaner canister and draw in warm engine compartment air? Did he remove the tube and run a hose to outside air? As far as I know no one knows for sure.
------------------ Rodney Dickman
Fiero Parts And Acc's Web Page: All new web page!:www.rodneydickman.com Rodney Dickman's Fiero accessories 7604 Treeview Drive Caledonia, WI 53108 Phone/Fax (262) 835-9575
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01:59 PM
FirstDrCar Member
Posts: 718 From: Buffalo, NY, USA Registered: Feb 2010
Yea I would buy Rodney's intake kit instead of the TLG intake, because as you may or may not know, the TLG intake is actually the opposite of a CAI..it draws in the hot air from the engine bay instead of outside the engine bay like the factory setup.
So what is better for an engine... hot air from the engine or air from the outside going through the CAI?
Just remove your OEM header, get a die grinder and grind off the excess material from inside the header ports. Then Remove the heatshield(tear apart) and Polish the outside of the header...somewhat free OBX header
Add and tweak Parts that will in theory help you gain power in the 2-4k rpm range.
A 4-2-1 header , a High-flow Cat and a OCELOT Cat-Back...May be a good combination.
Port match the Intake Manifold, replace the filter with a KNN, install a Fiero Side scoop, Remove the Water diverter and replace all the Ducting with Aluminum 2.5" Piping( From the Side scoop to the OEM filter housing)
If i remember correctly, FieroStore has a Higher Profile Camshaft for the Iron duke that will work with the Stock Valvetrain setup. --- Your also forgetting things that can help performance, like for example Lighter wheels/rims and a different tire profile to change the rpm/mph ratio...Even removing the stock A/C and installing the Drive belt for no A/c...Since A/c was a option.
I bought a Aluminum rim with 225/50-15" tires, the weight was lighter then the OEM 14" wheel & Tire setup. And it allowed my Fiero to spin the tires at will
You can even start removing excess weight, But what really matters is how you want it to be.
I've done none of this and is all lies :P ... or am i?
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03:08 PM
hyperv6 Member
Posts: 6002 From: Clinton, OH, USA Registered: Mar 2003
The only argument is how did he do this test? Did he just remove the intake tube from the throttle body or air cleaner canister and draw in warm engine compartment air? Did he remove the tube and run a hose to outside air? As far as I know no one knows for sure.
From what would expect there was a tube still hooked the the quater panel. There were limits to what you could do in Show Room Stock.
Also with Herb Adams I would not have much question with what he states. He is one of the best perfromance and racing engineers Pontiac ever had. He is still available and could still answer this question if you contact him.
The bottom line is that any cold air intake gain is limited. No matter the case it is not like putting a cam and intake on or turning up the boost 7 pounds. To really get any real gain out of these imporvments you need a car that can either adjust to the new parts or you need someone to tune the car to it on a real dyno. Generally they will need to put it on a Dyno and burn a chip. Stock systems with Mass air will adjust much and even they have their limits.
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05:16 PM
FirstDrCar Member
Posts: 718 From: Buffalo, NY, USA Registered: Feb 2010
So what is better for an engine... hot air from the engine or air from the outside going through the CAI?
There is no "better" for an engine per say, however hotter air is better for fuel economy, colder air is better for performance. This is why MPG drops in the winter time and lets you spin the tires easier! Lol. Well, not the only reason, but it is a factor.
[This message has been edited by mattwa (edited 12-11-2011).]
Soooo I am not sure if this was ever answered lol.
But I am gauging that going with Rodney's set up is probably better for the engine.... right?
Here is my 2 cents (speaking as TLG): Traditionally when looking for better performance, cold air is always better. The factory system is a cold air intake, and the amount of air flow provided by the factory setup is likely adequate for the engine. Spending money on a smooth pipe from the body panel to the engine bay probably won't make the car any faster, because the engine doesn't "need" more air anyway.
As others have pointed out, the duke displays characteristics kind of like the law of diminishing returns. You can throw all the performance mods at it you want, but the biggest change will happen in your pocket book. At the end of the day the duke is only capable of so much "performance".
So what's left if you can't achieve superb performance? What if you really just like the 2.5? Then the answer is to upgrade other things ALSO along with performance, such as style and the way the engine bay looks. Our K&N high flow intake is on the opposite side of the engine bay from the header, so the air isn't going to be completely scorched and the TLG intake looks awesome!
Some have said that the negative impact of the warmer air is negligible due to the low performance nature of the engine. It is arguable that the benefits of additional flow this system allows will outweigh the con of the incoming air temperature.
FirstDrCar:...I would like to keep my duke engine in the car. I do not want to do an engine swap, I do not want to do serious body modification. I want to keep my car mainly stock with "tasteful" upgrades, whether they involve interior, exterior, or engine wise.
So I am looking to "tastefully" upgrade my duke, not replace it. I would like the 84 Iron Duke to run as good as it possibly could. So when I say performance/HP gains, I know I will never match an engine swap or even the Fiero V6, but I would still like to upgrade my Duke.
From what I am gaining from this discussion, is I should just go with Rodney's True CAI product instead of the High Performance Air Intake from TLG. Is this correct?...
Ok, the only time the airflow needs improved is at high revs. The stock air intake is not part of the air flow restriction. High revs+Duke = UH OH!
Just like my black 2M4 you can keep the Duke in it, but it won't be the original block for long. Mine had 4 Duke blocks in it before I finally put in a completely stock re-manufactured 2.5.
But hey, what do I know?
BTW, be sure let us know when you have to "tastefully" replace your blown Duke.
[This message has been edited by 30+mpg (edited 12-12-2011).]
Not sure about the duke, but I gutted the intake baffle on my 3.4. I'm sure it made no performance difference, but it cost nothing and made it sound better.
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08:35 PM
FirstDrCar Member
Posts: 718 From: Buffalo, NY, USA Registered: Feb 2010
Ok, the only time the airflow needs improved is at high revs. The stock air intake is not part of the air flow restriction. High revs+Duke = UH OH!
Just like my black 2M4 you can keep the Duke in it, but it won't be the original block for long. Mine had 4 Duke blocks in it before I finally put in a completely stock re-manufactured 2.5.
But hey, what do I know?
BTW, be sure let us know when you have to "tastefully" replace your blown Duke.
I am not sure why you would need to put in a block so frequently. That to me does not make sense.
Not sure about the duke, but I gutted the intake baffle on my 3.4. I'm sure it made no performance difference, but it cost nothing and made it sound better.
Yes, removing that baffle gets you a really cool "intake sound" from the 2.8/3.4, but it doesn't do much of anything for the Duke, the Throttle Plate is too far away.
