Hoping it will be useful, i'm going to share how i designed and built my airbox setup, trumpets are from M3e46 stock airbox, 6 curved trumpets for less than 70 on ebay. Start from a piece of cardboard to make an idea of space, dimensions and clearances. Easy to cut and to model, i've done some modifications to radiator support too. Then take your cardboard modeled and transfer the shape to a pvc sheet, cut it and with a hot air gun slowly let it modeling itself on alternator and other parts. Cut the holes and fix the width with a piece of cardboard at the smaller end, try it and check clearances, make modifcations if needed. Seal it with papertape, double and triple layers, or the foam we are going to use will destroy it with its pressure or you'll waste it though leaks. Now it's time to fill it with pu foam, do not use the spray ones, they look cheaper but you will end spending more than you thought. Use instead a two components one, it will be smoother finished, faster and harder. Very important when vacuum will come into play... I used a 90kg/m3 kind and with 1,5 liter i made a "rock", POUR IT BY SMALL QUANTITIES OR PRESSURE IN LOWER ZONES WILL DESTROY YOUR MOULD, 500gr at time and you'll be fine. [video=youtube;EKAVeSB3YTs]https://www.youtube.com/watch?v=EKAVeSB3YTs[/video] Next step is to make the intake side, i have no photo but i used cardboard to make a "pyramid" and papertape to fix a piece of pvc tubing on its end, check clearance and position under the bonnet, then pour the last part of foam, this is what you will have once you open your loved mold, loved because at this point you will have spent nights, had arguments and nice moments with it Now it's time for the dirty work, sandpaper it, plaster it, sandpaper it, plaster it again, check clearances and position, sand paper it until is perfect. Foam pressure will have changed a little the mold shape and dimensions so check them and sandpaper it again Once is smooth and well shaped, paint it with some glossy paint, it has to be a good one. Gelcoat will be perfect, little expensive but fine, to save a little you can use boat finishing paint. Now we need external help, unless you have a very big band saw. If not ask to someone who has it, depending on shape could be necessary make a little stand under the mold or the saw will move it and ruin it. I did it with a little paperbox and more foam, cutted the shape of airbox in both side of the box, once the position was good for the cut i wanted i poured some foam and once dried will make the airbox stable. Now you have splitted it in two halfs glue it on a plain and glossy surface i used two wooden tables, 45x70 cm Wax it many times or the resin will stick it, there are few specific products, i've seen use olive oil too even though i dont recommend it. I used wax-based paint and polivinilic alcool. I wont describe how to layer fibers since there are lot of informations online, what i can suggest you is to recycle an old fridge motor to make vacuum instead of buy a vacuum pump and cool it with a fan, will be very stressed during the 12 hours resin curing time. Using a fridge motor will give you small power of vacuuing, so make one half a time or vacuum will not be very strong. One more thing, resin a 2cm border, will be useful to glue the parts together. What i used is: - less than 1kg of epoxy resin - 2 m2 of 140gr twill carbon fiber, take the 200gr will be easier to apply, two layers. - 2 m2 of 200gr fiberglass, very soft and surprisingly easy to use, two layers. - Vacuum bags, breathing tissue and silk finishing tissue. Still deciding the positions of trumpets, any opinion? OR More updates to come, will be glued, borders removed and glossy finished. As my first experience with fiberglass and airboxes i feel satisfied, will be a bigger SpecB one day. Lower radiator and smaller fan neede to free some space. Last thing, it was easier to make than describing it, many hours of work but nothing very complex. Hope you enjoyed it
Nice work, and thanks for sharing it with us. If anyone a bit nearer to me fancies having a go at vacuum bagging, I have a vacuum pump that could be made available.
Many m3 went for the CSL one. If someone is interested i could try reproduce them with fiber and see what happens. Thanks guys, more updates to come tonight
Really liking the fridge motor idea I`m a little confused about the bags / breathing tissue / CF Twill. Did you use 140, but recommend 200 ? I`ll google what the breathing tissue and silk is for. I`m used to wet layup, so do you do the same, then vag bag ? How do you know how much resin to use ? Usually I wet it out until it goes opaque, but I suspect with vac bagging, you can get away with less resin. I`d be concerned about not using enough ?
- I used 140 yes, but i found it hard to use, fibers are too sparse and it's easy to make them misaligned, with 200gr instead the tissue is thicker and softer, as i experienced with fiberglass. - Breathing tissue and silk explanations can be found here, they are one-use and cheap products useful only in case of vacuum, they help respectively air and excess resin coming out of tissue and leave a smooth surface while helping releasing of the breathing tissue. This is the layering order starting from the mould: - resin - fibeglass - resin - fiberglass - resin - carbon fiber - resin - carbon fiber - resin - silk peel ply - breather tissue - vacuum bag You know you put enough resin when layer becomes a little trasparent and wet, the good thing is that vacuuin allow you to make the mistake of using too much resin, the excess will be found on the breathing tissue once removed, no concerns then - Quantity is usually advertised, with 1kg you can do around 1,7m2 of tissues, i used 800gr with 1,4m2
No Gelcoat ? I thought the Carbon Fibre would be the first 2 layers onto the mould ? Some great info here. Vac-Bagging is the next thing I was looking to try, but didn`t really understand where the excess resin went, I do now
Gelcoat is useful, but it is very useful if you want a glossy surface. Since i layered OVER the mould and not inside, gelcoat would have left glossy surface inside the airbox, and we want it little rough to help air making the boundary layer. As above i layered over the mould so first layers are the ones you wont see from the outside, i kept carbonfiber as last only for aesthetic reasons. It was time for me to give something back to this forum lol
Yep, makes perfect sense. I`ve previously made female moulds, so the first layer is the one you end up seeing, I forgot this was in reverse
Some updates As adviced always check dimensions, i had to make some heavy mods to radiato frame. If you want more clearance use a fiat punto gt/td radiator. Will be lower and almost p&p.
