93silverbullet

iTrader: (7)

I met with my buddy this afternoon. He has one of those new STL machines that use ABS material. So the first prototype will be ready by the middle of next week, with the test fitting next Saturday. I agree with you that ABS makes better sense as a material.

With regards to the Davis (MazdaComp) radiator install, mine was a snap! No problems what so ever. I bought mine just before xmas so it maybe part of a newer batch (with mods already incorporated)??? Anyway fitment and craftsmanship were first rate, at least for me .

93silverbullet

iTrader: (7)

Well I spent some more time discussing the design options for the ducting with my "STL fabrication house". As I mentioned in one of my earlier posts, the STL machine we'll be using for this project uses ABS as the material (I even have a limitied choice of colors). So this prototype will be functional. With a wall thickness of .125" the ABS material should stand up very well to the heat/vibration/abuse of engine environment during the course of "regular" driving.

We did a 1/4" slice of the cross section (length wise) to double check for possible clearance issues. Found a few small problems with the underside curve of the IC duct. Revisions were to the design and now we're ready for the first full run. Interestingly the envelope of the STL machine is 8x8x12 so the duct will be made in 3 pieces and bonded together during final assembly. Since it's ABS the bonds will be as strong, if not stronger than the material itself.

Here is the final design prototype based off the most current revisions. As always your comments are welcome.

mauimoon

Looks really good. I'm shopping to replace my stock IC and this might just make the difference for me in going with the Greddy SMIC.

My one comment is in regards to the inlet design. The stock inlet has a center reinforcement which I have heard is required to keep air pressure at normal driving speeds from flexing the ABS and reducing the overall intake area, disrupting air flow, etc. A section of a Bic pen shaft and two screws would be the poor man's fix. But for such an elegant design as yours maybe you could come up with something better.

Kento

Hmm, I have a hard time believing that air pressure at normal driving speeds could flex the ABS plastic of the stock duct; too many holes in the stock setup for the pressure to bleed off at. The plastic is fairly thick in that area as well. I'm thinking they did it to keep the components on top of it (various wiring, supporting the AC receiver/drier, etc.) from collapsing it over time. As long as the ABS plastic is rigid enough, I don't think deleting the center support would be an issue, since it won't be supporting the AC receiver can and piping.

93silverbullet

iTrader: (7)

I still have my stock IC ducting and used it as a reference for my design. If you look closely to the stock duct you'll see that it is an assembly of 3 pieces of plastic (ABS??) riveted together. The upper and lower pieces that make up the section that matches up with the stock IC are a thickness of roughly .062", while the nose section is roughly .120-.125" in thickness. My design by comparison is .125" thick ABS throughout the entire design. This uniform thickness should add additionalrigidity to the overall design. I don't anticipate alot of flexing of the intake opening during even highspeed driving. Once the prototype is completed I'll double check to see what amount of flexing will occur by simply seeing how much force is required to actually flex the center section of the air intake (by hand of course, very scientific ).

I'll report back my findings. Thanks again for your input!

KevinK2

my mod'd PFS FRP duct inlet did start to close in the middle, due to general pinching and perhaps some residual molding stress, not aero loads. I did bond in a center brace from some plastic sheet.

mauimoon

By the way how do you guys with Greddy SMIC's deal with the cooling/insulation of the battery and AC condensor?

Jon

turbojeff

iTrader: (30)

Most likely the stock IC duct is made from either PP or PE, both resist fuels and oils very well. ABS doesn't fair so well under those chemicals.

An interesting note, in 94 Mazda kept the same or very similar IC duct design but it was converted to a 2 piece rather than a 3 piece design.

KevinK2

If you mean the can like ac component with sight glass, I wrapped it in foil backed insulation from hardware store. The 51R battery sits in a turboJeff tray, with a yellow "batt-mat' as an insulator. My underhood temps are far less than stock, so no need for a fully ducted battery.

I ported the lower inlet to the greddy, and freed up about a measured 1/2 psi drop at 10 lbs boost. This is not a high flow IC, like the PFS or ASP/M2.

Rx-7Addict

iTrader: (2)

any updates?

I need a duct for my greddy SMIC

race1

I would like to add my 2cents here, I am an Industrial Designer (specializing in product and furniture design) and I have a few questions, concerns about the ABS plastic in addition to what turbjeff mentioned.

I have some experience in vaccuum forming ABS plastic parts, and it was said that the ABS should hold up fine under normal driving conditions. Please correct me if i am wrong!
With a wall thickness of .125 [1/8th of an inch] (given there is no load or stress on the duct, which we know!) the heat factor in the engine compartment will still pose a significant problem with warpage regarding the duct.

Discuss amongst yourselves!

TT_Rex_7

You have to keep in mind that fresh, cool air is going to be rushing through the duct keeping the temps down. Also the duct is mostly down in front of the bumper, theres just a small portion actually in the engine compartment. The small portion thats in the engine compartment is also a ways away from the motor, so it won't get near as hot as the motor.

-Alex

BlueRex

That's true, but during traffic when heatsoak occurs the plastic could reach some significant temps. Not to mention that the duct is in contact with the intercooler itself which has hot compressed air fresh from the turbos going through it.

I guess the real question is at what temps does abs plastic warp and will the intercooler duct reach these temps?

TT_Rex_7

Even then, i'm sure it won't get hot enough to warp it. If its attached to the car it will somewhat help keep it from warping out of shape. The duct would get no where NEAR the temps of the motor. You could also put some sort of bracing inside of the duct to keep it in shape. It's not like it would get hot enough to melt. What is the stock duct made out of anyways?

-Alex

mauimoon

Is there an update? Was the first fab successful?

93silverbullet

iTrader: (7)

Sorry for not updating the status of this project, but I've been traveling quite a bit lately on business (damn work always get's in the way of my fun ).

Anyway, I had the prototype made and did a test fit. That's where I ran into some fitment issues (you'd think after all these years I'd have learned to measure correctly , reverse engineering is so FUN!). The A/C bracket (the mounting tab portion) hits the side of the new duct and does not allow a good fit, that and I actually wanted to open the fuse cover that is mounted on the front cross member. That along with the mounting angle of the IC itself caused an additional issue. I have since modified the design to take into account these problems. Since my plan is to still use the STL version as a working prototype I decided to add some internal stiffeners to addreess some of the concerns raised here about the possibility of the part deforming due to heat soaking. The ABS material being used has a thermal deflection temperature of 210 Degrees at 264 PSI and 230 Degrees at 66 PSI (well above the loading expected for the part, since its primary fuction is to direct air to the IC and not be a load bearing support).

I should have the new part next week sometime. But I'll be on the road again, so it will probably be a few weeks before I can report anything. I'll let everyone know how it works out.

Lil Red 7

Whenever you make a finished product. I want one. just tell me what to write on the check.

I am also an owner of the greddy smic. the stock ducting sucks. i have been watching this thread for awhile and cant wait until you finish. please let me know.
Thomas

93silverbullet

iTrader: (7)

Thanks. I'm also working on a another version fabricated in aluminum. This will undoubtly be much cheaper to make and it has the added benefit of being able to polish it !

If I go that route I'll make the plans available to anyone that wants them free of charge. That way you can have it made locally and pick your own material/finish. The issue with the prototype I'm making now is that to actually manufacture it would require molds be made and as you can see this not exactly a simple part. You would to make quite a few of them just to recover the cost of the tooling and that in turn would make the actual part cost prohibitive (which probably explains why Greddy made such a cheap version of the IC duct in the first place).

Anyway I'll keep everyone informed as to the progress of this project via this thread.

Lil Red 7

cool man well whatever it costs you to get made. i got the cash so let me know

thomas

if not i will make it out of sheetmetal or whatever to your specs

Rx-7Addict

iTrader: (2)

any idea for what pricing is going to be? are you making fiberglass, carbon fiber, aluminum??

ReadyKW

I'm looking at buying this IC, so if you come up with something, I'm in.

KevinK2

Suggestions:

Use the final prototype to make a cheap fiberglass female mold, for making a fiberglass duct, with external gelcoat. Could epoxy in a brace after molding.

Should be able to sub it out for production (might get a contact from KTW). Limited run of "cosmetic" (no vacuum bag or autoclave) carbon fiber ducts could also use same mold.

Make sure initial opening is at least as big as oem.

Slide on door gasket below flange would also be nice, and make for a more forgiving fit. M' Carr # 12335A42

Julian

iTrader: (14)

Don't give up on the molded FG or CF version. You can do it without tooling molds.
I made one using a temporary male plug mold out of a combo of foam, sheet plastic and balsa wood fit it to the IC and covered all in waxed plastic. Laid 2 ply’s of CF/Kevlar - epoxy over plug. This worked out giving very smooth interior and grainy but good exterior -- final cap ply covered top and sides for aesthetics. I had problems with duct growth beyond my original master templates, but I was crude in cutting cardboard templates and guessing skin thickness tolerance. I also needed to destroy my plug to get it out, but I would think with preplanning and CAD you could design a breakdown plug for reusing. Someday I will post photos of my duct ... fit to Greddy with Fluidyne rad. An advantage of plastic (epoxy), final fit up can be made with a little blow torch heating to reshape interference zones.

Fab Notes:
- I flanged my top and bolted to Greedy top face, used alum bar as backing bar which also formed a strut to car top frame.
- Used double sided tape around perimeter to mate to IC, (advantage of molding to actual IC (behind plastic) is a perfect fit up.
- Did not put strut in opening, has not closed up, lower lip extends well pass opening (air would push this down and thus open)
- Heat soak does not melt or soften, I just can back from first test run this weekend BBORR race; 118 miles at 140 mph in hot West Texas.
- Had to relocate IC a bit; about 3/8 in back and ¼ toward battery tray. I drilled new bolt hole in trans. sub-frame. No big deal, watch out for hoses underneath and engine pulley clearance.
- CF/red Kevlar was purely for looks .. I had the cloth. But it is as light as a feather. About half weight of OEM duct and more than twice as big.
- Without vacuum bagging, this piece is still as strong as hell. A 2 layer composite is nothing fancy to make, and this thing does not hold your life in its hands.
- Use VERY GOOD epoxy, I use WEST System. The real stuff! for high performance boat building.
- If I did again, I would try to lay some heat shield material (mat/foil) into the bottom layers to reduce rad. Heat input .. but this will take another 1/8in out of the duct internal size, which is already very tight over the fans.
- Would cut down my rad fan support bosses to get more space

Sorry for long story, but the product is in the details

desmond

any update on the duct or the pricing?

93silverbullet

iTrader: (7)

None at this point. Sorry guys I've been traveling way too much for business (and personel) reasons lately. It looks like this project is going to be on the back burner for awhile longer .