Tubing issues Turbo to IC, IC to manifold

[Grant]

Okay need to run some new tubing for my Colt Rally car from turbo to ic to intake manifold. Any recommendations for Silicone Tubing vs. Aluminum tubing? Also how do you join the silicone tubing if making a custom set of pipes. Mine will end up being pretty complicated and would cost a ton to have someone manufacture so we are doing it ourselves. I know my rally car is not a Legacy (yet) but this is info that I think would be useful to others here and I hold people here's opinion higher than other forums around. Thanks in advance. I'll post some pics later just to show how ghetto the current setup is. Eg. The pipe after the intercooler TOUCHES the exhaust manifolds.

[deyes]

A cheap and effective way to go is to get a muffler shop to press bend a set of aluminized steel intercooler pipes for you and use silicone couplers. Many shops can do mandrel bends, and mandrel style bends (bends without wrinkles and a near constant radius but without the use of a mandrel) but that route is invariably more expensive.

You want hard pipes because they don't expand under pressure, causing stress cracks and ruptures (probably not a problem with silicone) and the hard pipes improve throttle response and resist heat damage better. Depending on the outlet of your turbo and the inlet and outlet diameter of your intercooler you will sacrifice little in the way of flow with a pressbent setup as long as the bends are not too accute and you use a pipe diameter that is slightly larger than diameters of your turbo and intercooler inlet/outlets.

Another plus for using aluminized mild steel exhaust tubing for intercooler pipes as opposed to using silicone tubing or aluminum, is that its much cheaper and easier to weld brackets for the tubing to keep it fastened to the engine compartment so that there is less chance of your pipes coming loose due to movement during something as strenuous as a rally. If you do it right you may have enough money left over for some DEI turbo and exhaust/intercooler piping wrap to keep underhood temps way down.

[Grant]

It's all currently wrapped now, all the piping and the exhaust manifold. The setup I have planned will be really cool (in both ways, temp and style) and allow much more flow. This car was built to rally in the early 90s and there doesn't appear to have been much consideration to flow amount taken into account. At one point the pipe between the turbo and the ic appears to have less than an inch in diameter. They also took just about the longest route possible getting the pipes there. I'm working on pics of the current setup as well as some drawings for my new ideas and I'll post them when I get it. Thanks for the reccomendations deyes.

[JasonGrahn]

A cheap and effective way to go is to get a muffler shop to press bend a set of aluminized steel intercooler pipes for you and use silicone couplers. Many shops can do mandrel bends, and mandrel style bends (bends without wrinkles and a near constant radius but without the use of a mandrel) but that route is invariably more expensive.

Road Race Engineering (http://www.roadraceengineering.com/) sells mandrel bends. I've help built both exhausts as well as intakes with their pipes.

You want hard pipes because they don't expand under pressure, causing stress cracks and ruptures (probably not a problem with silicone) and the hard pipes improve throttle response and resist heat damage better.

Agreed. Both mild steel and aluminum sheds heat better then silicone as well.

[Grant]

Are there any "rules of thumb" so to say about diameter of tubing with respect to turbo size. I have a relatively small but quick spooling turbo. The boost gauge in the car says aroun 11-12 psi currently. The current intake piping is only maybe 1" at the smallest and 1.5" at the largest. Any reason I wouldn't want to go to big?