Well here was my first and very miserably failed attempt at a high flow air box for my TPI.

It started off with wanting a lid that flows more volume. Stock doesnt allow for crap as you can see....


I wanted to make it bigger, so I made this mold addition out of styrofoam as a concept to work around. Here it is, a bunch of blocks glued together and sanded down to the general shape I wanted it...


Heres what it should have looked like with more volume!


I attached it to the stock airbox (spare)...


and taped it all together...



Now, I thought it looked good up until here but this is where it all went wrong...

I put glued the underside of wax paper to the tape so it would stick there. Then i used a fiberglass repair kit to go on top of my mold. I figured it would dry, crack off the wax paper, and I could use it as a replacement! No such luck. It came out awful. Maybe I just suck at working with fiberglass, but heres the pic...(please dont laugh too hard...)



So I gave up on the fiberglass stuff. My next attempt is already in the works with really thin and lightweight aluminum sheets and ducts from the hardware store. Keep an eye out for that, I'm hoping it works better than this! Well, I'm 90% sure it will....

In the meantime, any input is welcome!

 

yea u didnt glass that right at all

 

Hmmm. Maybe I'm missing something but there is no way a design like that will fit under any hood. The stock lid gets thin for a reason.

 

Fiberglass wise what Im going to be tryin next is using mdf boad and making a frame for what Im going to build then use fabric and cover it then apply the resin directly to it. I had to many issues when building the center console and didnt like how it turned out so Im going to use that route or maybe taking a giant piece of dock foam and make a mold then clear coat it so the resin doesnt eat thru it and then go from there. I like the attempt though, good idea. Did you check the clearence with the one u were gunna make? I havent taken a look at my car recently since it just got back from gettin the new engine installed but seems like it would be really tight. One more thing, have u ever thought about trying to use your hood? Considering that its functunal if you could make one like what is on the SS camaros that may actually give u better results. Just a thought

 

Good attempt. 1/2 the battle is getting up enough nerve to try stuff.

I'd check with clearance of your mockup piece.

That fiberglass repair stuff works okay for small projects. If you want anything strong I would recommend getting better resin. I use to get my from uscomposites.com I believe the resin I liked was the B-220 construction resin. blue colored and is about thickness of water. You can find good fiberglass on eBay. Biaxial weave works great for corners and is much stronger than regular mat. That's what they use for boat hulls. You can usually find it cheap on eBay because those companies don't want small pieces. I bought 70 lbs of it once for around $45 shipped.

For a small part like that I'd say 3 or 4 layers of regular mat or 2 layers of biaxial would be a good start.

Things I can see just looking at picture:

Never use plastic containers if you avoid it with resin. It'll eat through it. Metal and glass containers are nice. Or Ice Cream Buckets. Those work well for big projects because you can just mix up the resin you need and toss them easy enough.

That bondo spreader isn't going to work well. You will want to get some 2" brushes from Walmart or similiar place. Make sure to get the 50 cent throw away ones. There not worth the effort of cleaning.

That plastic mat isn't going to protect from good resin. The good stuff will eat through it overtime.

Use smaller fiberglass mat pieces. You're using way too big of sheets. If you cut the mat into 2"x2" or 3"x3" pieces it's much easier to work with and bend around the corners. It'll be stronger due to overlapping.

Try stabbing at the mat more with the resin. I can see some air bubbles still. That causes brittle areas.

Use aluminum foil with turtle wax. That works great to be able to peel it apart. Duct tape/Masking Tape with turtle wax also works. For Molds I recommend a watery type of liquid called PVA on the uscomposites.com site. It's basically a release agent... green liquid you paint on and once it's dried it will make a thin layer that will peel/flake off when removed.

Make sure you're ratio is correct. Going to lean on hardner will not cure the glass, but too much will cure it way to fast and you'll have a hard time using the resin in time and your piece will be brittle once done.

 

Looks like a good first attempt. Did you measure the clearance to make sure there is enough room? Did you think about re-routing it to another location or different design? Like I said, looks like a good start to what could be something.

 

well, I won't agree that you can't make nice stuff out of the bondo and other "repair kit stuff," I have...

I will add that you kind of find that some things work for you, some don't, and really till you get to production level of things the same things don't work for everyone with fiberglass. I have had good luck with spreaders and things where others prefer brushes...

WRT to cheap brushes... get a box of chip brushes from harbor freight, they're really cheap and actually fairly decent.

 

Check out 1bad91Z's High Flow Airbox. You can find it by entering "High Flow Airbox" in search. He just modified the factory box by adding material to the bottom to reduce the restriction and converting the outlet to 4" pipe. You can add about 1/2" height safely. In fact I just checked my clearance yesterday using molding clay(Play Doh LOL!). I have 5/8" to play with before I run into the hood.

I thought about fiberglass too. In fact your attempt isnt a bad start. You just need to cut off all the slag and apply another coat. Repeat this until you get the thickness you want then grind it to final shape and paint it. If you mix the resin right and apply the sheet with enough resin, it should come out nice and solid.

 

One trick to fiberglass is cut it into small strips then saturate them and lay them down. One thing you might try also is Bondo brand fiber glass resin gel. Its thick and moldable. Drys solid and strong too. I actually thought about taking a factory airbox, removing the bottom, builiding up the top with fiberglass to the size I want then carving out the plastic/ fiberglass to the new shape. I think the fiberglass would bond well enough to the plastic. Its just one idea.

 

I agree with others in saying the fiberglass cloth you used is not suited for this type of project. The hair kind that you have is made for patching holes on flat or level surface. Try obtaining some of the cloth that is woven (both kinds should be available at a parts store). You will have better luck molding that kind and have less of a stringy mess. Using cheap brushes also works well.

 

I also agree with '83 Crossfire TA'. It comes back to what you like to use. I spoke from my experience. This project could be done with mat I just prefer the biaxial type.

I think that might still be savagable also. I'd agree cutting off the excess. It would also be a good idea to cut open any large air bubbles in the fiberglass before attempting to save it. At least that way your 2nd coat would fill those gaps and make it more solid.

I'd recommend using some turtle wax next time.

If you can't get the part to pop free easily some wooden clothes pins to use as wedges and a hammer usually works well for molds. :-)

 

that one I'll entirely agree with...

I've used turtle wax and cloths pins before also... and I've never been able to do anything useful with mat, it always falls apart on me unless I use it between layers of cloth anyway.

 

People never seem to realize that airflow has to do with volume as much as the path the air takes. The reason that air box is so flat is because width wise it makes up in volume for what a normal air box would flow. An 8" round is going to flow the same as a 4" round that's oval'ed out to 10".

The most restrictive part of that system has nothing to do with how flat that air box is, but with the 90 degree intake the air takes right when it enters the system, IMHO.

I forget the exact figures, but every 90 degree bend cuts your airflow significantly. Turning vanes can help eliminate that.

Mathius

 

Hey guys, thanks for all the input! Ya I should have used the cloth and not the mat, but the kit I bought came with mat and I thought it came with cloth. I just figured I would try it out since I already paid for it and opened it.

Anyways, I do have plenty of clearance under my hood for this. I did some mods for this project on a different thread. You can check it out here if you like...
https://www.thirdgen.org/forums/body...lteration.html

And here is what lead me to want more airflow from the airbox...
https://www.thirdgen.org/forums/fabr...d-air-ram.html


Feel free to post on these too if you have any ideas or input. But I should have the new thread up with my attempt using the aluminum for the airbox by next weekend. Thanks again guys and keep the replies coming!

 

I've done some fibreglass work in the past, mostly cosmetic repairs on airplane baggage pods. I've a few suggestions in addition to/contrary to fireturd350's advice, but as they say, more than one way to skin a cat.

I'd recommend using an epoxy resin as they are generally more durable than polyesters. Mix only a small amount of resin at a time; resin is exothermic and has a short pot life, and if you mix more than you can use in ten or fifteen minutes, you'll end up throwing a bunch out.

I'd recommend using disposable paper cups for mixing resin. The kind without the waxy coating inside is better as the resin will absorb the wax, which can be undesirable especially if you're making larger layered parts in multiple stages.

When using cloth it is generally desirable to use fewer larger pieces than more smaller chunks; with chopped strand mat it doesn't matter and smaller pieces will be easier to work with.

My preferred method of spreading resin in cloth is to lay down a sheet of cloth over a sheet of plastic, pour some resin onto the mat, then lay another sheet of plastic over top and use a bondo spreader or squeegee to spread the resin. Saturate the cloth so it appears transparent and squeeze excess resin out the edges. Using this method gets you full strength of the part with no extra weight (from unreinforced plastic). You can also lay out patterns on the plastic sheet, then cut the piece out exactly while it's still in plastic. Remove the bottom layer of plastic, lay the cloth up, and leave the top layer of plastic on until the resin cures. You can put pressure on top of the plastic via sandbags or other weights to hold the parts in place, although the preferred method is use of a vacuum pump. The plastic will peel right off once the resin is cured.


That's about all I can think of right now, and keep in mind these are just suggestions that I've had success with in the past, not the be-all and end-all instructions of FRPs.

 

the aluminum build is coming along quite nicely! im really feeling good about this one! i should be finished in about a week and a half, then i will put up a thread on that.

 

Good call. It's amazing to me the people who cry OMG a LT1 with a TPI airbox will be bogged down etc.

Anyone ever look at the stock LS1 intake? The cross section isn't that much different than a TPI.


_________________
- Gary R.
1986 Z28 "KNOCKER"

My Racecar build thread

 

I used a combo of mat and cloth no issues with either just cloth was better for forming while keeping a good layer of glass.. (mat likes to spread apart when you work in the resin)

 

Thats a nice design. I have imgined that idea before, of running the intake out to the back of each headlamp assy. There's alot of air at these points. At any rate, I just finished my hi flow air lid. I went with a similar design to 1bad91Z's. I added a little extra material in the tight area where the box makes the bend to clear the hood. I found I had 5/8" to play with there and I used it all.

My construction method is the same as 1bad's, using acrylic two part adhesive and plastic to enlarge the box. This does require commitment as you first must destroy the OE peice by cutting it almost in half. Then the building starts. Materials cost me $80. Now I have an air filter lid that fits in the stock location and will flow twice as much air through its 4" outlet. Using the stock location makes it work perfectly with my newly installed ram air ducts.

BTW, I sense some controversy over the value of modifying this peice. Ibad91Z had flow bench tests run on the stock air filter lid and it flowed 450cfm as I remember. The modified lid flows 850cfm. As far as how air flows around bends, air flows almost exactly like water. Thats why today's OE intakes, cyl heads, and turbo systems are designed using fluid dynamics modeling software. An excellent example of this is the new Ford Eco Boost V6(350ftlbs from 1,500 rpm to redline), designed using state of the art fluid dynamics. So when considering air flow, just try to picture what water would do. How would water behave in a given situation? Then you know how air will behave.

 

Air is considered a fluid, but in reality it is not for one simple reason: Fluids are (generally) not compressible. Air is. The only reason they're going to using a form of fluid dynamics considering liquids as well is because of the fuel in the air charge.

 

Well I have been working on my second attempt for a while now. Its taking me longer than I first thought because I just dont have a whole lot of spare time. Anyways, Im using sheet metal and all I have to do left is figure out how to weld it or join it together in some way.

Heres a teaser pic of what I have come up with so far...

 

hope ur good at tig welding.. thats about it.. if u got one or know somone that does practice welding soda cand back together.. not as easy as it looks.. only other way i can see this staying together is rivits but idk if u left enought material on there to rivit it.. cool design ill be interesed in seeing it complete.. and i saw ur hood mod thread.. nice idea and ill give it to u bro u got a lotta ***** cutting into a nice ss hood like that i know i couldnt do that and i really really want that hood sooo badd..

 

That fits with the h0od shut? Dayummmmm.... I was under the impression that the TPI lid was designed with the hood height in mind.

 

It was, the bottle neck in the snorkel was to clear the front hood latch structure

No way that fits under a stock hood without lots of hacking

 

I love this thread and you're ability to work at things. I definitely have the same mind set as you. Won't lie though, when I saw this picture I thought "if you looked up overkill in the dictionary...".

 

Without insulating that thing it's going to absorb underhood heat like a mother. Believe me, part of what I do for a living is HVAC install and that's all that is is ductwork. You should definately have stuck with your fiberglass approach if this is your upgrade.

If you weren't going to weld that you should have made up seams to bend over so it could be riveted or something. Even so without some kind of and even WITH some kind of lock you'll probably never seal that thing 100% without some kind of duct seal, silicone, silver tape, etc.

I'm all for people doing custom fabrication, but it sure is disappointing to see someone put a whole lot of time into something and then find out it isn't going to work like they want. You should have discussed the idea further instead of trying to make it out to be a big secret. Some of us could probably have helped you get around some of the major flaws you've got going on there. First thing I would have suggested was if you were going the sheetmetal route, you should have gone round so you could get some of that nice thermal slip on insulation. Now you're going to have to wrap it with something.

And like everyone else, I'm skeptical it'll fit under a stock hood.

Mathius

 

he could braze it or use alloy solder from the welding stores.. it would make a great mold if it fit/worked

 

Ya I know a few welders and they said the same thing, just use a low heat and do it in small sections far apart, then back when it cools down, but they said it could be done. And thanks for the compliment! ***** like a planet... brain like a pea! Haha!

It was. But my hood is not stock. Plus I modded it... look for the link above.

Yet again, see the link above in one of my earlier posts...

Haha! I know right! I feel like Tim "The Tool Man" Taylor! "All it needs is a little bit more POWER!!!!!! ARGH ARGH ARGH!!!!"

Yet again... NOT STOCK! But thanks for the advice, I'm always open for input. But I dont think heat will be an issue for me. Trust me.

As far as it being a "Big secret", It wasnt. Just a side project of mine I want to do to improve the performance of my baby.

That was another option one of the welders gave me. I may give that a shot too. Thanks man.


And as far as steps go and clearance for my hood, I will throw up a thread of how I got to that point step by step sometime soon when I can get around to it. Keep checkin in and I will attach the link...

 

Do you know how much heat or cold sheet metal retains? There's a reason all supply lines are insulated. You're trapping that piece under your hood right next to your radiator. I'll be very very surprised if it doesn't get hot.

Mathius