intake piping options (mandrel bends)

riceandbeans · Post by **riceandbeans** » Sat May 20, 2006 9:33 pm

I need educated help.

I'm going to need intake piping for my 1st gen RX-7 13BT swap. The diameter of the intake pipe should be on the order of 2"-2.5" (haven't run the calcs yet, just guessing). I have not yet decided on the material I would like to use, but I am leaning toward thin-walled aluminum or stainless mandrel bends, coupled together with necessary flexible fittings.

I am unable to find the bends and couplings for which I am looking. I do not want some rice-tastic honda kit with crappy parts that cost too much and have no quality control. I just want to buy from a reputable place, buy only the bends I need, knowing ahead of time all the dimensions and material properties of the piping. Anybody know of a place that sells what I'm looking for?

MegaScott · Post by **MegaScott** » Sat May 20, 2006 10:20 pm

One of the best, Burns Stainless, sells Aluminum tubing and mandrel bends. As well as all your other turbo needs.

http://www.burnsstainless.com/AluminumT ... mtube.html

lmr052 · Post by **lmr052** » Sun May 21, 2006 1:58 am

You may want to see if you can source stainless donuts if you need really small radii. Just cut them up to suit your need. I managed to fit 400mm manifold runners under the bonnet of a Lotus 7 replica.

riceandbeans · Post by **riceandbeans** » Sun May 21, 2006 4:21 am

Awesome, this is exactly the kind of thing I was looking for. I love this forum- completely devoid of punk kids and chumps with more money than brains. Thanks again guys.

boost junkie · Post by **boost junkie** » Sun May 21, 2006 6:35 am

This place has real good prices on bends. Popular with the honda-tech fabrictation crowd...

http://store.racing-solutions.org

Jedrik · Post by **Jedrik** » Sun May 21, 2006 4:18 pm

I would proably start with aluminum since its less expencive and easyer to work with than staneless for an intake.. and not much harder to weld.

If your intake pipe dosent run too close to exhaust you might consider making one out of composites... fiberglass/epoxy. This will reduce heat transfer and you can get as creative as you want. Note: if you havent done any composite molding expect a few failures... getting forms out of the inside of tubes can be a real... dificulty. Use a good quiality laminating epoxy from sowere like TAP plastic or a Marine store. DONOT use polyester resin!

Also, I found silicon molding material, the two part stuff, commonly used for ceraimic and plastic molding art stuff can make great costom flex mounts. Its main problem is its little slippery so I like to mold a bump or flange into the tubing it fitts over. A few weld blobs does well.
Oh I almost forgot, it is reinforsed with 2-3 layers of verry loose fiberglass cloth or old nylons.

Here is my use for intercooler pipeing running about 150F and 7 psi.
See the blue tubeing here:
http://www.home.earthlink.net/~s.riddel ... ignfab.htm

If you are interested in more detail I think I have more pictures somewere.

PSIG · Post by **PSIG** » Sun May 21, 2006 4:59 pm

Jedrik wrote:...getting forms out of the inside of tubes can be a real... dificulty. ...

I have used round lengths of foam such as the 'pool floating noodles', rollbar padding and A/C pipe insulation to make intake runners and duct tube forms for fiberglassing. The cool thing is that it's relatively easy to remove the foam from the finished item by melting with solvent. I also tried using woven fiberglass tubing reinforcement on it, but found that simply spiral wrapping with 'glass tape was simple and cheaper.

I haven't tried making the silicone couplings like yours, but the spiral wrapped tape technique may be good for that too. Whatcha think?

renns · Post by **renns** » Sun May 21, 2006 5:15 pm

Another option for mandrel bends is Headers By Ed. This place has good prices, but stocks mostly mild steel, and a bit of 304 stainless.

https://www.headersbyed.com/mandrelb.htm

You may also want to check out Wagner. They have a huge selection of bends in a variety of metals. They supply parts primarily for hand-rail applications, with wall thicknesses of 0.120" and higher, but there's no reason they wouldn't work for your intake application.

http://www.rbwagner.com/pages/Rbwagner.html

Roger.

Jedrik · Post by **Jedrik** » Mon May 22, 2006 8:28 am

PSIG

The tape can be handy on the epoxy/glass though I find its edges stiff and hard to contour. But it keeps the fraying mess down.

You want a very loose weave for the silicon so that there is nice blocks of rubber going in and out. The silicon wont actualy stick to the glass and will delaminate if it isnt well encapsulated.
I like 1-2 in. wide strips cut at 45 deg. then wrap it around like making a cast. Single strands of glass pulled out of cloth can also be spiraled around... slow but controlable.

About 1/8 in thickness is fine for low pressures (15 psi?)
For an intake pipe seeing slight vacume you may want more like 1/4 in
depends alot on the size of tube.
For certain a person would have to expect to do a bit of experimenting at first!

zx1100e · Post by **zx1100e** » Mon May 22, 2006 12:13 pm

I used a 100 dollar ebay kit for my rx7, and a 100 dollar intercooler. the quality was fine search ebay for intercooler piping. It took about 1.5 kits including 2 45 degree silicone couplers at the fmic, and 28 inches of raw silicone hose to use as couplers and for 2 10 inch sections connecting the intake hat and turbo outlets to the intrercoolers. Its worth mentioning that mine is an fc with a 13bre running stock re twins.