Custom Fibreglass Enclosed Airbox And Snorkel For Gt-t

[Angelecles]

Hey guys,

Ive been looking at the Gruppe M intakes to suit the R34 GTR and think they look sh*t hot, also the idea of a partition that is readily available to cover my open pod is not really too appealing. This is mainly because I'm thinking where is it pulling air from if you use stock IC piping. Im not big on cutting holes in my engine bay so im back looking at something that resembles the stock design with some Gruppe M styling cues.

I have a feeling people are going to ask "why dont you use the stock airbox with a K&N panel?" well i thought that would be too easy and i like trying new things and I want my engine bay to look a bit different. Anyway here goes.

Im gonna attempt to make an enclosed airbox with a massive snorkel out of fibreglass that hopefully improve the look of my engine bay while im at it.

This is sort of what im basing my design on (except not carbon/kevlar and probably not as nice )

First of all just a bit of disclaimer. I am not a professional fibreglass guy and do not pretend to be. You will also see this for youself as you scroll down to see my backyard fabrication techniques. Im sure there is about 1001 ways to do this better but im just doing it the best way I can. If anyone can suggest better ways to do this please do as I have not yet completed this mod and currently working on this.

Parts Needed:

Sharp Stanley blade (a hot wire cutter is better but i dont have one so mines a bit butchered)

Block of expanded polystyrene (about $15 from clark rubber)

duct tape or that brown shiny packing tape (F**k all from the $2 shop)

PVA glue

Pins - what your mum used to sew stuff

Glue that will not melt the polystyrene - Pretty much anything that doesnt have acetone in it (Liquid nails, silicone)

Fibreglass resin + hardener (Needs to be epoxy resin or else you risk melting through the polystyrene)

Cheap paint brushes (Heaps of them)

Fibreglass chopped strand mat

hint: is if you go to bunnings and see the fibreglass resins look for one with a little surfboard on it because they use epoxy to repair surfboards (not to melt the foam inside the board)

dremel with a cutting tool

Car filler

Heaps of sandpaper

Paint etc

I probably forgot some stuff but im nowhere near finishing yet so this is still a work in progress thread

Step 1:

Get your foam block and start cutting pieces and slowly make up a mould for your box using the silicone and pins to keep it together.

Im trying to make mine bolt down to the stock position so i started at the front and started making a little channel to not foul the stock IC piping

As you go it will start to take shape (abeit rough as) like mine after about 10 mins of gluing random bits of foam together

Depending on the glue you use, you might have to do this over two or so sessions so the glue has a chance to dry. The quicker the better. Silicone is pretty good, gets tacky pretty fast and isnt too messy if you dont use huge amounts of it.

Heres another photo after a bit more gluing.

Anyway, grab a beer and let your glue dry ready for step 2.

Step 2:

Grab your sharp stanley blade/hot wire cutter etc and start smoothing out the foam blocks into one smoothed out shape. Keep cutting and trial fitting to see if the box is too big etc.

A couple of photos after about 5 mins of butchery.

Step 3:

Cover your smoothed out box in duct tape or packing tape. Dont be tight with it. Half a roll should do it easy but if you wanna use more go for it.

This is what it should look like afterward.

After you cover the foam in tape. Paint all over it with PVA glue. Do a couple of coats (this will be a kind of mould release so the tape doesnt stick to the resin when we want to pull the foam out later)

The more the better so do a few coats.

Step 4:

Laying the first coat of fibreglass. Be sure to mix the resin according to the instructions and be in a well ventilated area.

Paint a light coat of resin over the box so when you start putting the chopped matting over it, it wont move around too much.

Start laying mat over it and saturating it with the resin, try to be even all over the box.

Be sure not to cut the mat, tear it with your hand. Its easier to lay and it also blends better with the laid matting.

This is roughly what your box should look like after a coat of resin + matting

Leave it to dry and then repeat until you are happy with the thickness of the box.

I did two coats so it ended up about 2mm thick (i dont want it too thick because im gonna smooth bog over the top of it to make the finish prettier later on.)

Step 5:

After your second/third coats get your dremel and cut the top of the box. (the bit that probably looks pretty average, i marked it with a permanent market first. Then can start pulling the foam out of the box. Should start breaking away pretty easy.

This is what your box should look like after you gut the foam out of the box.

Step 6:

Trial fit the box in the car, see what you did wrong..

In my case i stuffed up the angle where the AFM will later connect to the box.

This is a photo after i cut a part out of the box and tried to make it line up properly.

Dodgy i know. I used kebab skewers, duct tape and silicone to get the angle. I will then trim the box a bit more and fill the hole.

NOTE: If you guys learn from my mistakes, Step 6 will be much shorter on your job. I rushed mine a bit and am now paying for it.

Once i finish roughing the base i will start on the lid in a further post. Stay tuned people.

[ashneel]

looking good. would be interested if it looks decent and if you wanna make more

[dori34]

whats wrong with the airbox's u done in the group buy ash. lol

[PLYNX]

Thats a nice bit of fiberglassing.

I was thinking that it might of been easier to strip out the entire section and wax it heavily with mould realease, then fiberglass it, to get the inner profile and build from there ? ? ?

[Angelecles]

Thats a nice bit of fiberglassing.

I was thinking that it might of been easier to strip out the entire section and wax it heavily with mould realease, then fiberglass it, to get the inner profile and build from there ? ? ?

thanks mate,

sorry i dont follow what you mean. Strip out the foam? what part would i be waxing? This information could be really useful because i want to start on the lid/snorkel this weekend.

I should really go to a fibreglass supplier, i need heaps more resin and i couldnt find mould release at bunnings anywhere so i just improvised.

[ashneel]

whats wrong with the airbox's u done in the group buy ash. lol

nothing wrong with my box dori. but fiberglass one looks cool lol

[PLYNX]

I meant strip out the entire gard space, waxing it out and glassing the entire to get the profile you need.

As to ideas to the air box lid see the post further down on the same thing and my try at it. You'll find pics there !

[PLYNX]

Ah found em !

[Angelecles]

hey mate,

Your setup looks really good. Looks to work really well with the stock snorkel. I was gonna attempt to make a sort of "big mouth" snorkel, mainly because i dont have the stock snorkel so if i make one i dont need to go and buy one. What are your thoughts on your setup? Did it make an improvement? Is it much quieter than the exposed pod? Any noticeable perfomance gain?

Also, you were saying about waxing the body of the car and glassing straight onto it. I noticed a lot of people used masking tape with similar results. If I want to make the snorkel front I will need the front of it to butt up against top of the radiator support and am thinking this is what ill do. I was planning to make a nice gap for the rad with some sort of temporary filler (blu tac or something like that) then tape on top of that so it doesnt rub against the rad when its installed. Do you think this will work?

[ashneel]

Ah found em !

dude that box is sick. did you make it???

wanna make me one

[Angelecles]

Ok guys so i got home early from work today so i thought i would start trying to rough out the lid and snorkel. Im starting to get used to cutting the foam with the stanley knife so it didnt turn out as rough as the bottom of the box but it still needs to be trimmed. I will start on that on the weekend after i get back from work but heres a progress report anyway.

I started roughing out the bottom of the lid. I ended up making it out of two layers of foam so i could get some more angles and a bit more of a big mouth design happening. I will have to trim a fair bit off the lid behind the light though so it clears the bonnet.

Heres the bottom layer of it.

Then after another half an hour of adding bits and pieces.

Im attempting to make the snorkel as big as i possibly can so i can. I tried to make the box a minimum opening of at least the same as a 3" pipe being a touch less than 44 cm2

A couple of the measurements that i did do, the snorkel is 260mm x 80mm (the bit thats hatched with permanent marker) which ends up being 208 cm2 a fair bit bigger than 3". I expect that i will have to cut about a good 10mm off the top of it though but it should be a massive improvement over the stock hot air thats getting sucked in.

At the thinnest point of the snorkel (just above the stock IC piping) the area is 64 cm2 which is the equivalent to a 3.6" pipe which I'm more than happy with. I thought if i end up making the snorkel bigger than the diameter of the standard AFM I would be more than happy.

Just a note, these are all gonna be inside diameters. I will measure them again once i shave bits of it off just to see if any of these measurements have changed dramatically.

Heres a pic of what the current setup is.

Edited March 20, 2009 by Angelecles

[Angelecles]

Ok so i started smoothing out the lid this morning. Had to cut off less than what i originally thought to clear the bonnet. Shaved a fair bit off but the size of the snorkel pretty much remains unchanged so should make some sort of improvement hopefully. We will see anyway.

Heres a couple of pics of the lid after i trimmed it a bit.

and another one from the side showing where i had to trim the front to clear the bonnet.

and one from a bit lower showing the size of the inlet.

It still needs to be trimmed a bit more to suit the base of the airbox but i havent drilled it and fixed it to the car yet to know where i still need to trim.

[r34_25GT]

Great write up man its looking good so far

[Basti]

when you are done with this one, make me one for my 33

[Angelecles]

OK so it turned a bit pair shaped today.

I started coating the lid today.. Looked real good at first..

But this is where i went wrong. I used cling wrap instead of duct tape and didnt do the coat of PVA glue this time. My mistake so after about 10 mins it started caving in.

Heres what the lid looked like when i did the first coat on the lid

I was pretty impressed with myself at this stage.

Anywhere heres where it goes downhill. About 15 mins later this is what it looks like..

and..

It ended up setting like this. Bit disappointed. But at least im fill it with bog and use it as a mould for the lid i will end up using.

Not all is lost, just a bit of a pain in the a55..

[mfxae86]

styrefoam melts at the first touch of fiberglass or bog, lol. there is a green foam that is used in plastic flower settings ect that can take the resin, i have used it heaps b4, we called it pattern foam, most fiberglass shops should carry it... will save you some heart ache next time.

[Craved]

styrefoam melts at the first touch of fiberglass or bog, lol. there is a green foam that is used in plastic flower settings ect that can take the resin, i have used it heaps b4, we called it pattern foam, most fiberglass shops should carry it... will save you some heart ache next time.

this stuff dissolves in acetone, so its easy to remove from the inside of your new plug too.

[dori34]

PLYNX, that airbox setup is awesome!

[PLYNX]

PLYNX, that airbox setup is awesome!

Thanks man !

Just in the process of stripping out the entire gard section on my spare car and and am going to glass it all out again ! Wasnt happy with the first result.

[randomagg]

Made one of these the other day. Quite easy and you get high from the fumes! I made a mould out of cardboard then covered it with aluminium foil worked quite well. and i used heat sheilding that i bought from clark rubber and heat resistant glue from bunnings. thanks