So i know a cold air intake is just sucking colder more dense air from an area away from the engine. Now the Fiero has a intake that goes outside the engine bay through a vent. So would it already have a cold air intake from factory? Just asking cause I've seen photos of aftermarket cold air intakes on here but the intake is still in the engine bay so isn't it still getting hot air from the engine. Didn't they make it worse?
[This message has been edited by Carlin (edited 09-08-2025).]
So i know a cold air intake is just sucking colder more dense air from an area away from the engine. Now the Fiero has a intake that goes outside the engine bay through a vent. So would it already have a cold air intake from factory? Just asking cause I've seen photos of aftermarket cold air intakes on here but the intake is still in the engine bay so isn't it still getting hot air from the engine. Didn't they make it worse?
Most front-engined cars have some sort of little scoop where the car gets air from behind the front bumper... usually in a gap behind the headlights or a little bit lower in the grill.
The Fiero's air does in fact come from behind the driver's side door on the side of the car. This is actually probably one of the most optimal places for it, and I'd have to say that other than RAM-AIR systems from Pontiac in the 90s and 2000s... this is about as close as you're going to get.
The only part of the air intake that's less than great, is the water separator and sound baffling system. This is a large plastic box that sits directly behind the inlet on the side of the car, and hides up behind the fender and engine bay. It's not in the engine bay, but between the fender and the firewall. You can see it if you pull back the rear driver's side inner wheel liner (just a few screws).
This box basically serves two purposes: 1 - It helps separate water from air, by forcing the air up a crazy incline while the water drops to the bottom. 2 - It helps reduce engine noise and harmonics by baffling the sound of the incoming air
It's a little pricey, but works really well. Back in the 90s, people used to take the end of a hammer and shove it in there, and it would break the plastic wall separating the air baffle, and then you have a more direct air-flow. You could do that, but personally I would get Rodney's kit. I'll say that removing the baffle really improves the sound of the engine. As long as you have a decent exhaust that isn't too loud or obnoxious, having the baffle removed really improves the sound of your exhaust.
Even on my daughter's Iron Duke in deceleration (say in 2nd gear from 30), the car sounds like an Italian sportscar... like, we're going to have to do a video where she records it, it's friggin' amazing, and the Iron Duke is not generally known for having good sound. The V6 has much better acoustics.
I think user Patrick on here has a video of his Iron Duke when he's driving around after doing something to it... and it sounds pretty awesome also.
I think user Patrick on here has a video of his Iron Duke when he's driving around after doing something to it... and it sounds pretty awesome also.
I suspect this might be the video you're thinking of. Most of my other Fiero videos are of my Formula, but I had fun for a few years autocrossing my swapped in 5-spd and dual-exhaust (with high flow cat) '84 duke before I acquired the Formula. This video was shot in 2010. I'm always happy to show off my (lack of) autocross skillz.
(Note: There was a 2nd camera mounted on the rear license plate, basically just to record the duke's dual-exhaust audio, so there's probably no "intake" sound in this video.)
The "burning rubber" smell mentioned at the end was one of the cones under the car being melted by a hot cat/exhaust! lol
[This message has been edited by Patrick (edited 09-08-2025).]
As mentioned by 82TA you can increase the cold air flow to the engine by easily removing the baffle in the distribution box. You remove the air grill and that will open the duct passage. Using a hammer handle put it in the duct back to the air box and crack out the obstruction. Then reach in pull the broken piece out and screw the grill back in place. That water distribution box with the baffle does absolutely nothing, If it will improve horsepower is debatable but I have run all my Fieros without the box baffle and/or a straight pipe in heavy rain and no water seems to reach the air filter. I replaced the element with a fabric K&N unit just in case.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, 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 "
I suspect this might be the video you're thinking of. Most of my other Fiero videos are of my Formula, but I had fun for a few years autocrossing my swapped in 5-spd and dual-exhaust (with high flow cat) '84 duke before I acquired the Formula. This video was shot in 2010. I'm always happy to show off my (lack of) autocross skillz.
(Note: There was a 2nd camera mounted on the rear license plate, basically just to record the duke's dual-exhaust audio, so there's probably no "intake" sound in this video.)
The "burning rubber" smell mentioned at the end was one of the cones under the car being melted by a hot cat/exhaust! lol
Yeah, this is the one... the engine sounds really healthy. I'm sure it's probably not even really doing it justice. The sound my daughter's engine makes is unlike anything I've ever heard from an Iron Duke before in my life. The other three Dukes I've owned (an automatic 84, automatic 85, and ... I forget), both of them sounded like a tractor (or mail truck... obviously, hah). But exhaust was not something I even took notice of. This is what my daughter's car has:
1 - Totally stock 1-7/8" Fiero 4 cyl exhaust. 2 - Brand new Ocelot 2" catalytic converter. 3 - Fiero Store shorty header (more or less looks like a stock manifold)
It sounds really, really healthy (it's not, has a cracked cyl head, but no milkshake... and I'm fixing it this weekend for her). The shorty header actually made almost no difference, just slightly throatier. We used an 88 manifold on it (basically the same), and the sound was more or less the same. I only used the shorty header because I wanted to fix a flange down-pipe leak, and I got a better seal with that design.
Can I ask what camera / mic setup you used? I've been thinking of trying to get something like this... I see them use Go Pros and such on TV shows, but I never really have any idea what to get. How did you mount the camera on the back, etc.? ... and did you have an external microphone or did it just work?
As mentioned by 82TA you can increase the cold air flow to the engine by easily removing the baffle in the distribution box. You remove the air grill and that will open the duct passage. Using a hammer handle put it in the duct back to the air box and crack out the obstruction. Then reach in pull the broken piece out and screw the grill back in place. That water distribution box with the baffle does absolutely nothing, If it will improve horsepower is debatable but I have run all my Fieros without the box baffle and/or a straight pipe in heavy rain and no water seems to reach the air filter. I replaced the element with a fabric K&N unit just in case.
The engine pulls the air in, the baffle may remove some restriction and make it flow easier, but it will NOT increase performance.
I also have removed the water separator on my 4.9 Formula and replaced it with Rodney's tube - no change in performance.
I also run a K&N air filter in the stock air cleaner housing.
Can I ask what camera / mic setup you used? I've been thinking of trying to get something like this... I see them use Go Pros and such on TV shows, but I never really have any idea what to get. How did you mount the camera on the back, etc.? ... and did you have an external microphone or did it just work?
When I shot that video above in 2010, I was using two thumb-sized crappy cameras that I had bought a bunch of for about $5 apiece!
CLICK FOR FULL SIZE
(Interestingly enough, I saw these same old digital cameras being flogged online somewhere recently for like $50 each. No mention was made that these are ancient low-res standard definition pieces of crap.)
I custom made a bracket to mount one of the cameras in the location of the rear license plate, just to record the audio, as audio recorded inside the car sounds lousy. Full disclosure, I also enhanced the audio somewhat using an audio app on my PC.
As good as the duke may or may not sound in that video, it pales in comparison to what my Formula sounds like. If you start Here and work your way down, you'll be able to see/hear several examples of the Formula, plus you'll see the great little camera I ended up using for full stereo audio, hi-def video.
I custom made a bracket to mount one of the cameras in the location of the rear license plate, just to record the audio, as audio recorded inside the car sounds lousy. Full disclosure, I also enhanced the audio somewhat using an audio app on my PC.
As good as the duke may or may not sound in that video, it pales in comparison to what my Formula sounds like. If you start Here and work your way down, you'll be able to see/hear several examples of the Formula, plus you'll see the great little camera I ended up using for full stereo audio, hi-def video.
Yeah... I remember that video too, it does sound awesome.
I want to do the same for my daughter's Fiero (once we get the head swapped out). The sound it makes is something that needs to be shared. It's the healthiest sounding Duke I've ever heard in my life. It sounds similar to yours, just a little bit "cleaner" if that makes sense.
She's really put in a lot of work to make the interior mostly quiet... lots of sound deadening, and even using plastic film and rubber isolators between many of the plastic parts to reduce any squeaks. The thing literally feels like a new car when you're driving it... EXCEPT, she hasn't done the fornt-end yet, so it's funny. Everything about the car feels brand new, and the front suspension is totally shot, haha...
But the engine sounds amazing... deceleration from ~3,200rpms in 3rd gear or 2nd gear... just sounds amazing. I mean... I've had lots of cool cars over the years, and many have sounded good. But I was just so impressed with the sound from this Duke. It's not like a huge engine sound... or even a burble or anything like that... it just (surprisingly) sounds really, really well tuned. And it's probably because all the sensors are new, injector is new... we even went with new valves and valve-trane components, so even though it's zero-lash, there's no slop.
I'm sure the decoupler pulley and the harmonic balancer also made a difference in improving the sound and feel of the motor too.
Slight tangent here... but when I had my 87 running (3.1 upgrade, blah blah). I had the "Holley" side scoop. With the window open, I could actually hear the intake. It was a high pitched thrashing sound, almost like farm equipment harvesting wheat or something. Was kind of weird... hah...
Slight tangent here... but when I had my 87 running (3.1 upgrade, blah blah). I had the "Holley" side scoop. With the window open, I could actually hear the intake. It was a high pitched thrashing sound, almost like farm equipment harvesting wheat or something. Was kind of weird... hah...
Yeah, not exactly the awe-inspiring deep "whoooah" that the four-barrel carb secondaries opening on a BBC sound like. lol
No mention was made that these are ancient low-res standard definition pieces of crap.
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