From what I have gathered on this forum, the most restrictive part of the intake system is the upper, middle and lower intakes, and everyone says that the stock cold air intake is a great design that does not need to be improved, I can' seem to wrap my mind around the great design, it looks like crazy straw that gets fairly restrictive in some points. I personally do not know the flow of the upper and middle intake pieces, but I have seen the stock cold air intake set-up and it seems that it could definitely use some improvement. I know that some research has been done to show that stock cold air intake is supposedly the best set-up, but from what i understand, the test was done on a dyno, which in my opinion shows nothing since the car is sitting still, of course it is going to suck in the same amount of air, and if i recall it was tested stock set-up versus open throttle body. To me the parts of the stock cold air set-up look pretty restrictive. I know that the water separator serves a purpose, but it seems to impede flow a lot. I have taken that out years ago and have had no problems with a wet filter or anything like that. The other issue that i see is the bottom of the air filter housing. It seems like there are better options then the three slots that are left for the engine to suck air from, I know rodney sell's the ultimate air box brace thing that needs to be welded in there. But i was hoping to make it even less restrictive then that, without any welding involved.

Stock:


I was thinking something more along the lines of this for the air box bottom:


I thought i read somewhere on here a member that used a air canister lid from another GM car that had clips instead of the nut on the top. Does anyone have any info on this or ideas on how to mount the stock air box bottom with the bracing cut out? I am not expecting any massive gains or anything like that, but i always thought that the least amount of restriction for the intake is ideal, and to have the air flow smooth with the least amount of bends and interference.

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Muffler remover
Topic: doityourself - 1$ - true cold air intake
https://www.fiero.nl/forum/Forum3/HTML/000058.html

mid 80's cavalier air box, use the the base with stock fiero lid to keep side air intake, can use lids with hole in centre, but you end up with a hot air instead
Topic: Improving the stock V-6 cold air intake can
https://www.fiero.nl/forum/Forum2/HTML/096287.html

Cut out bottom to size of ring in the air can, and no need for fancy coupler as it would fit over the ring of the stock intake base, just cut out the cross. I cut more and built a custom elbow out of abs

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1988 Fiero GT

So you are ignoring actual testing results because you 'feel' they are wrong and the intake just 'looks' restrictive to you?

I am sure, given your scientific methodology, that any 'improvements' yu make in something no one else thinks need improvement will show huge gains - measured by SOP (seat of the pants) dynmamometer, of course.

the 'actual test results' are not very clear. by what I have read from the mighty Herb Adams article, what was compared was the stock cold air intake vs no intake - which also means Hot air intake - sucking hot air from right above the y-pipe. which says to me - a clear flowing Cold air intake WILL make an improvement.
yes, I agree the stock system is very good. but - it certainly can be improved upon. getting rid of the curves - especially the water seperator. and, next - the rubber snorkle. the rubber soaks up heat. the corrogation wrecks flow.

quote Originally posted by BillS: So you are ignoring actual testing results because you 'feel' they are wrong and the intake just 'looks' restrictive to you? I am sure, given your scientific methodology, that any 'improvements' yu make in something no one else thinks need improvement will show huge gains - measured by SOP (seat of the pants) dynmamometer, of course.

So in the past almost 9 years that you have been a member on this forum, you have only posted 117 times, and for some odd reason you felt the need for this to be one of your posts, just to give me a hard time. What is your problem? Oh and by the way, if you are gonna be a jerk and bash my topic, and idea, then why don't you at least check your spelling first, so you do not come across like an uneducated idiot. "Yu" is not a word! Did i say i was expecting any gains from it? NO! Not to mention the fact that it does not just LOOK restrictive, it IS restrictive. It is not a question of if the flow can be improved, because that is obvious to anyone with eyes, but the question is whether the Fiero intake could use the air that is supplied to it? Clearly Rodney thinks that there is some room for improvement in the stock intake system or he wouldn't have made two different parts that address the areas that i was planning to. So in my opinion you can keep your post number at 117 unless you have anything constructive to say, or unless you are working towards a negative rating.

[This message has been edited by zmcdonal (edited 03-03-2009).]

Back on topic I actually just went to the junkyard and picked up a plastic air box with clips. There are 2 problems I have with it. 1 being the where the tube attaches to go to the TB the stock Fiero one is too small (not too much problem to edit the rubber tube to fit). 2. There is a cross in the bottom of the air can itself, the one in the Fiero is part of the base so that needs to be cut out. I am yet to start this project because I am not sure how to attach the air box to the base w/o the center post. Silicone holding it down would work but then it would never come off. Anybody got some ideas on how they would do/did this?

quote Originally posted by Riddick85: Back on topic I actually just went to the junkyard and picked up a plastic air box with clips. There are 2 problems I have with it. 1 being the where the tube attaches to go to the TB the stock Fiero one is too small (not too much problem to edit the rubber tube to fit). 2. There is a cross in the bottom of the air can itself, the one in the Fiero is part of the base so that needs to be cut out. I am yet to start this project because I am not sure how to attach the air box to the base w/o the center post. Silicone holding it down would work but then it would never come off. Anybody got some ideas on how they would do/did this?

Your #2 question was my main concern as well. My best guess from Daniel's post is that you just modify the current restrictive bracket with a hole so that the base of the air canister will fit through it and then reconnect the stock elbow with the hose clamp to the bottom of the canister. Kind of like in this pic, but with the modified bracket in between the canister and the hose:



I would think that this would keep it from going anywhere, but i was hoping for some more info/ideas on that as well. He had mentioned that he had made a custom elbow out of ABS.

On another note, how much smaller is the Fiero tube compared to the outlet size on the canister?

It almost fits so my idea was to shave some of the rubber out of the inside of the tube to get it to fit. Also the outlet is oval not a perfect circle but that doesn't matter much. I can take some pics tomorrow and post them if you want.

You will get ZERO gains until you replace the engine with a 3800sc or larger. a $1.25 cheapie paper air filter in that box can flow more air DIRTY than the 2.8 or even the 3.4 can suck in at WOT >3800RPM.

And yes I know this for a fact. I actually did the measurements. up to the TB there is almost no pressure drop. Adding a K&N filter made zero difference in readings.

Stock exhaust is far more restrictive than the intake, start fixing that way before you even think of touching the intake. Then focus on the upper plenum piece. hogging out he restriction in that piece will increase the rpm where the car runs out of air from 3800-4000 to 4500 rpm. or just buy a Truelo intake to skip those 30 hours of work and let it pull hard up to the point the engine flys apart from overspeed.

there are no free or cheap HP gains in the fiero... well except for the fixing the Exhaust by porting the logs and the Y pipe.

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Best RV, Camper, and Trailer dealer in West Michigan. http://www.cliffstrailersales.com and he's a fiero owner too!

To get the snorkel to fit I used hot water to allow the rubber to expand just enough to slide over, it is a a snug fit, but it works.

I made a elbow that puhes forwards to get easier access to the hole to the fender. You can see a section of white from above as I used a piece of gas vent as the extra piece, and another piece of black was rotated for the right angle. If I were to do it again a easier method would be to just cut out the cross of the metal bracket, and sand out the cross and most of the lip on the plastic piece and set them together using the stock lower elbow. I probably would have done this but my lower elbow did not fit well, so I made the abs version. You should test this yourself as it may be a tight enough fit for you, especially if you put a bolt in the lid and a spacer to the engine grill as a hold down. This would have worked great in my case since a 10" fan is under the engine vent whith minimal clearance to the mechanism seen above as the centre bolt on the lid.

The intake snorkel also works great at holding the can in place, just needed to be adjusted, and in my case I moved the evap can out of the way behind the passanger in the fenderwell below the expansion tank.

eddited to add:
The below picture shows the stock bracket in place, and the 3" abs elbow underneath The hole is actually just over 3.5" as that is the size of the 3" abs put into the aircleaner can.

[This message has been edited by Daniel (edited 03-03-2009).]

I look at it this way. The stock system indicates that air must travel through about 2? - 3? feet of twisty, tortured and convoluted air passages just to get to the intake valve. This is somewhat ridiculous if you think about it for even a minute. The poor old (25yr) cylinder has to suck it's air through an extended straw to breath. Anything you can do to help it out the better IMHO.

Arn

The bottom coupler is pictured below
Red is the new air can,
Blue and Green are the the pieces of the coupler built from the 3" abs pipe, to fit through the bottom of the can, and glued together.

The abs ring is not glued to the air housing, but could be. I did this seperate so it could be removed by cutting it off without damaging the air can



Before you go too far going this method, just remove the bottom plastic cross with a hole saw, leaving the part that protrudes upward, and the metal bottom will fall of. Just set this piece on the stock bracket with cross still intact, and see how you will get the air tube on tho the engine, I moved the evap can for extra clearance, you may find an easier alternative but I thought this could not hurt air movement in the engine bay. The plastic can could then be bolted down as a test without removing the stock cross. You could also put in a bolt down like Rodney sells, but I went this method to remove any cross that could cause turbulance. I just slide the air can through the steel bracket and into the elbow, and there is an interferance fit holding the can in place with little room above the can if it were to move upwards ( air fans on engine grill.)

Any specific questions ask here and I will try to get back to you

You can cut out the center piece of the stock mount,,drill 2 small holes ,and screw the canister to the mount,I,ll leave it to you how you attach the lid to the canister !! ..I was going to use L brackets ..on a lightly modified engine there will be no performance gain,unless you smooth out flow
Often the canister outlet where the hose mounts is rusty,,,I used J B weld to repair mine ..If it is really damaged you can use a Progresso soup can(Im serious) to repair.. sawing thru can is pain in buttocks ,,only for the mizerly cheap skinflints like myself who scour/eyeball the ground while walking,, for desirable pennies..

Yes you read correctly it was love at second sight,, she was a tad overweight..I did not know she was wealthy the first time !!

[This message has been edited by uhlanstan (edited 03-03-2009).]

quote Originally posted by timgray: You will get ZERO gains until you replace the engine with a 3800sc or larger. a $1.25 cheapie paper air filter in that box can flow more air DIRTY than the 2.8 or even the 3.4 can suck in at WOT >3800RPM. And yes I know this for a fact. I actually did the measurements. up to the TB there is almost no pressure drop. Adding a K&N filter made zero difference in readings. Stock exhaust is far more restrictive than the intake, start fixing that way before you even think of touching the intake. Then focus on the upper plenum piece. hogging out he restriction in that piece will increase the rpm where the car runs out of air from 3800-4000 to 4500 rpm. or just buy a Truelo intake to skip those 30 hours of work and let it pull hard up to the point the engine flys apart from overspeed. there are no free or cheap HP gains in the fiero... well except for the fixing the Exhaust by porting the logs and the Y pipe.

I am not really looking for any gains from this. I have a 3.4PR with the trueleo intake and headers and a mild cam and a bunch of other goodies(too many to name). Doing more to see if I like the change in intake sound of not.

Problem with screwing it to the base is that the air filter needs the flat on the bottom to seal and with screws there...not much seal.

I really and at a loss to attach this thing tho. I already have a tube from the scoop on the rear quarter panel to the base of the air box but securely attaching this thing and being able to remove it if need be I am kinda at a loss. I still have that bolt in the mounting hole from the cavalier but I don't think that will help much.

I will post a few pics of the cavalier air box tomorrow for those that want some pics.

You will notice an increase in intake sound/ hiss from stock, I noticed a louder intake than the when i had just the intake muffler delete.

I will try to get a picture with the stock base and the modded air can base tonight as there is roughly 1/4 inch lip that can be left outside of the cross sticking up that can help hold this air can in place. (I have 2 cavalier air boxes, may try using one on my daily driver as the air filter is larger than in the 98 gtp) I would try using the cavalier bolt to hold it down, just create an L bracket bolted/ riveted to the bottom side of the stock steel filter mount. I would probabaly also use some sort of knob , such as a drawer pull that has a flat top to keep the filter box on ths ring of the filter mount high enough to touch the engine grills, as well as being a central spot to lift the lid and keep the bolt hole plugged.

(my filter lid has no clearance between the air can handle that I am using and the 10" fan on the engine grill for air movement. I could have gone this route, I did not because the elbow I had did not seal well around the metal base, and the replacement I was using from another car intake was restrictive as it went down close to 2.5" diameter in the middle of the bend.)

You can bolt this filter box down temporarily with the centre bolt as per stock, leaving in the cross in allowing you to figure out how you would want it held down with the cross removed.

If I'm not mistaken the TPI 350 in the mid 80s up Trans AM used what appears to be the same air filter. If I'm correct that would suggest the system is more than adequate for the 2.8L. Even with twists and turns the total resistance has to be high enough to impede the airflow the 2.8L is able to demand. Perhaps a good scoop over the external inlet would be more effective since at speed you would think the air rushing past the vent would cause a pressure drop similar to what the decklid vents experience pulling hot air through them. The ram air hood on the latest Trans Am was said to be good for an additional 25 hp.

[This message has been edited by Joseph Upson (edited 03-04-2009).]

my 86GT
Heres another spot you can open up



my 87GT
[img]http://i16.photobucket.com/albums/b50/francis44/100_0809.jpg[/imh]



as timgray pointed out, none of the above inlet mods are worth doing with a stock intake, you just wont feel and dif at all.

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[IMG]




trueleo.com
RSpiderII@aol.com

quote Originally posted by timgray: You will get ZERO gains until you replace the engine with a 3800sc or larger. a $1.25 cheapie paper air filter in that box can flow more air DIRTY than the 2.8 or even the 3.4 can suck in at WOT >3800RPM. And yes I know this for a fact. I actually did the measurements. up to the TB there is almost no pressure drop. Adding a K&N filter made zero difference in readings.

Do you think if enough of us say this people will finally understand? I expect not - many times they just want some project so as to have the impression they are doing something useful to the car, and obviously don't welcome anyone with actual facts. Your advice is spot on - there are lots of BHP to be liberated with exhaust modification and none from intake mods. PS - I am not sure how anyone can conclude using the psychic method that just because there are turns in the intake tract, it MUST be restrictive. I suppose they'd say the same thing if it were the size of a sewer pipe (which it almost is, compared to the restrictions in the intake further up) but still had turns in it.

Sort of reminds me of the kids who put 3" and 4" exhausts on their Japanese cars - that feed back into 1 1/2" pipe, and they think they are accomplishing something. Oh well, their money.

And to zmcdonal - I may have put you off with my tone, which was terse due to lack of time when I posted, but you'd do well to at least assess what people say even if it disagrees with you, and criticize my data, not my typing skill. I can pretty much assure you that I have built far more cars for street and track than you have, based on YOUR tone (I make the assumption that you are pretty young). If that's incorrect, then I am mistaken.

http://www.rodneydickman.com/ColdAirIntake.html

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Rodney Dickman

Fiero Parts And Acc's Web Page:
www.rodneydickman.com
Rodney Dickman's Fiero accessories
7604 Treeview Drive
Caledonia, WI 53108
Phone/Fax (262) 835-9575

Enough with the negatives about doing this. Every single thread that is about this or mentions this has someone with the disclaimer "No point because No gain." If nothing else it sounds different and that is a fact that cant be argued, it really sounds different. Maybe people just want to be different.

Anyway, pics of the cavalier box.
http://i85.photobucket.com/...ddik695/CIMG1555.jpg
http://i85.photobucket.com/...ddik695/CIMG1556.jpg
http://i85.photobucket.com/...ddik695/CIMG1557.jpg
http://i85.photobucket.com/...ddik695/CIMG1558.jpg
And for me it is going into:
http://i85.photobucket.com/...ddik695/CIMG1523.jpg
Definitely not stock.

In the pics you should be able to see everything mentioned here. Also I left the bolt in the hole that bolted the box down in the cavalier. That is probably the best spot to to attach it from.
There is also a metal plate attached to the bottom of the box that will fall off once the cross is cut out of the bottom. I have some spare cork material that I will try and use a gasket material and see if that works.

Edit: The lid in the pic is the lid that came with the new air box. Kinda useless in this application.

[This message has been edited by Riddick85 (edited 03-04-2009).]

quote Originally posted by Rodney: http://www.rodneydickman.com/ColdAirIntake.html

Good product good price

An image of the coupler apart (the one in car is glued together, this may be for the daily driver, an 98 gtp)


Without the coupler, the plastic can be slid on with no changes to the fiero mount (my spare in pic) with only the bottom of the air can bored out This way you can make sure it fits, and use the centre bolt temporarily with the stock fiero lid until you decide on the final mount configuration.


different view of above


I probabaly would have went Rodney's route but I don't have a welder

Why are you sticking with the 90 degree turn of the stock air filter, hmm? For example, in my garage is a Jeep Cherokee and it's air box looks like



Think of other cars and possibilities.

You could glue ~3 rare earth magnets (3/8" - 1/2" diameter larger would probabaly be too strong) to the bottom of the plastic air can, then use seran wrap and put silicone under the air can as a good air seal, letting it cure on a flat surface(seran wrap between flat surface and silicone). This would allow easy removal but still help secure the air can.

A different style air box could be used, like Gokart Mozart has said, But a rectangular filter wouild need to be quite large to gave the same filtering media as the stock fiero one and most have 2 90 degree bends comming out of the box, such as in his picture above. I was tempted with the K&N Apollo intake with 2.75" flanges, but for the price and all those bolts I would have used a cone filter setup from, a ford minivan, mustang or truck as they have a similar setup that is easier to check, and much more affordable. I used the cavalier air box for ease of install, and that it looks very close to stock.

You don't need the 2 90 degree turns. Forgive the crudeness but this could work with a rectangular filter. Connect to the entry and the front of the throttle body.

2 of many things one can do:





No breathing problems plus I still have a rain baffle.

I think the "rain baffle" was used to also quiet the intake sound inside the wheel well compartment....

I felt that the tubing from the air box to the TB with it's ribs would cause a lot of turbulence along with the box thing inside the wheel well. I purchased from the Fiero Store their cold air intake - I liked it because of the shape and inside smoothness for high flow but then it was sitting inside the engine bay right over the Y pipe which was wrong also just like someone spoke of.. Not to mention the stupid location for the O2 sensor..... ((( they drilled a hole into the air cleaner to except the O2!!!! )) WTF?

At Autozone they have a "Civic" cold air intake tube for like 30 or 40 bucks.... Turns out that the curve in it and shape with the Fiero store one is a perfect match.

1/ It put the air cleaner into the wheel well for outside cold air - 2/ I welded or for some JB weld a fitting to the tube for the O2 sensor - 3/ Sounds nice/mean and loud air sucking sound ( I get the turbo question a lot ) - 4/ It's the same dia of the Fiero store one to connect the 2.

I won't say how much gain I got or if any but I will say that when I first bought the Fiero store one and installed it, there wasn't really any improvement because it was sucking in hot air. Once I added the other piece it felt like it was ALIVE with some "little" gain/improvement.










I have also the stage II scoops to help the flow into the wheel well... I'm in the process of fitting them right now....

ooohh

aaahh (shiny = faster)

Again, I know of 2 Honda Civic owners who installed a CAI with the opening under the front bumper. Both suffered a bent rod due to water being sucked in while driving in the rain.

Picture going down the highway in the rain and a semi passes in the opposite direction. While passing the semi hits a large puddle of water and throws up a sheet of water, part of which gets "scooped" and sucked.

Could happen, that's why I still have a rain baffle.

BTW When I first got my Coupe w/ the 3800, it didn't have the stock Fiero air cleaner setup. After I installed I the stock air cleaner the engine was a lot quieter with no noticeable decrease in performance.

If you want to make your engine's breathing louder, replace the Cat. with a straight pipe.

My son did on his Fiero, then put a glass pac in because he claimed the car sounded like a tank!

[This message has been edited by 30+mpg (edited 03-06-2009).]

The flow is not a problem even if very "twisty" as long as it is not blocked ,,you young wippersnappers have forgotten HOT ROD basics ,basic engine modification is to increase efficiency where ever possible,, to redeuce weight where ever possible !!it is because so many performance products are available to buy that the basics are not practiced you can rest assured in the garages of nascar and F1 the basics are religeously practised.
You can screw the can down ,, you could even use round head metal screws.
I will eventually have a curved pipe from the TBI intake down to the bottom where the can is now bolted,,similar to unboundmo but a more downward flow with the filter inside the pipe
You do not always gain Horse power or torque ,, you want to increase efficiency and at a later date it may pay off in increase air flow that you need .
oops bat attack back later

[This message has been edited by uhlanstan (edited 03-08-2009).]

Guess I should of shown the inside smothness for the smart person. Shinny = ooohhs for me. ..... and I'm not done with the pieces yet not to mention the air cleaner location. Yes I have thought about rain and other things "scooping and sucking" in. Even the heat from the bottom radiator tubing, if any. I will say that the air cleaner is not directly in the opening. In fact you can't see it from the outside. But you did have a good point... Just didn't want you to imply or think that I'm stupid. - Thanks for lookin out - frankly I like my set up... and that's just it - my set up.