# Custom Turbo Inlet pipe in metal?



## pneffkell (Jul 8, 2015)

So I have basically completed by build. I have an 02 fwd with a hybrid turbo from turbo concepts. I chose them because the use a quality cast turbo housing that was engineered in house. So far I really like the turbo. The one issue I have is that the current turbo inlet pipe is not optima and is very restricted in some areas. 

I am thinking about building something out of stainless so the I can keep the rigidity of the pipe. Has anyone here done a customer turbo pipe like this before? I am really just looking for inspiration and some feedback before I start


Thanks in advance


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## recaro19 (Feb 17, 2016)

If your custom metal fabrication is anything like your spelling then you are in big trouble mate! Lol

All jokes aside, keep us posted with your findings. Looking forward to seeing updates.


Sent from my iPhone using Tapatalk


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## l88m22vette (Mar 2, 2006)

I'd try to make a silicone piece fit, the biggest issue with a metal TIP is heatsoak, a stock k03/k04 or a hybrid will produce a lot of heat and more heat = less power


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## pneffkell (Jul 8, 2015)

*Interesting*

I guess I don't understand the heat soak issue. The car has an FMIC on it and all of the piping on the other side of the turbo are metal. Thats got to be 3X the length of what I would have with the turbo inlet pipe, plus the turbo inlet is pre-turbo so its only seeing fresh cooler air. I would still decouple it from the turbo by attaching it with a silicon coupler. Are you suggesting that the heat from the turbo would travel back up the inlet and heat soak the incoming air?


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## Gonzalo1495 (Feb 2, 2015)

pneffkell said:


> Are you suggesting that the heat from the turbo would travel back up the inlet and heat soak the incoming air?


This is the same effect that occurs to the intake manifold when it is mated directly to the block. That is why the phenolic spacer was born!


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## pneffkell (Jul 8, 2015)

Right but that would only occur if the metal of the turbo touched the metal of the inlet pipe. IF the inlet pipe is attached to the turbo with a silicon coupler and the two metals don't touch them heat transfer would not occur. Basically that is what the phenolic spacer does as well.


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## Alcrerion (Feb 16, 2012)

I ended up coming up with something like this for my inlet. It's made out of a 3"ID aluminum elbow and a silicone elbow on the compressor inlet. This is it before it received barbs for the DV recirculate and and a barb for the N75. Unfortunately I don't have a photo of what it currently looks like.

It's made of metal but I've also taken other measures to try and keep engine bay temps down as much as possible by wrapping my downpipe and a CTS blanket over the turbine housing. As of this time I don't have any IAT measurements to see whether its heat soaking or not.


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## l88m22vette (Mar 2, 2006)

Hotter is hotter (and less dense), if you want metal I'd thermal coat it or use foil to repel heat.


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## 20v master (May 7, 2009)

l88m22vette said:


> I'd try to make a silicone piece fit, the biggest issue with a metal TIP is heatsoak, a stock k03/k04 or a hybrid will produce a lot of heat and more heat = less power


What do you think that ambient air that is constantly moving through this metal inlet does? You're back to spouting off randon internet statements with no proof. You don't "heat soak" a turbo inlet, it's not an intercooler. And plastic and silicone get hot in the engine bay too. Do they magically not transfer heat to the intake air? You think bigger turbos don't make heat? All turbos make heat, it's the nature of compression. Using that statement to conclude that metal inlet pipes will heat soak is pretty silly though. I guess Arnold doesn't know what he's doing with those metal inlets for his turbo kits. :screwy:


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## Alcrerion (Feb 16, 2012)

This is roughly the finished product of the intake that you can see on the right. Has a bung welded for the DV recirculation and am debating running another small bung to retain the N75's recirculation or letting it blow off atmospherically. 

Haven't yet decided whether or not I'll be coating them or using some type of reflective heat tape. opcorn:

Hopefully this gives you a little inspiration for your project.


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## l88m22vette (Mar 2, 2006)

20v master said:


> What do you think that ambient air that is constantly moving through this metal inlet does? You're back to spouting off randon internet statements with no proof. You don't "heat soak" a turbo inlet, it's not an intercooler. And plastic and silicone get hot in the engine bay too. Do they magically not transfer heat to the intake air? You think bigger turbos don't make heat? All turbos make heat, it's the nature of compression. Using that statement to conclude that metal inlet pipes will heat soak is pretty silly though. I guess Arnold doesn't know what he's doing with those metal inlets for his turbo kits. :screwy:


Heat retention = heat soak, its not as pronounced as an intercooler but still matters, and using steel piping as pictured means longer retention. There is plenty of info about how a cold-air intake does actually add a few hp to a turbo (because of higher air density and/or flow), and most of those are silicone or composite. If he wants to do it why not just sweat the details now and be done with it, he sounds detail-oriented, worrying about 1% here and 2% there adds up.


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## 20v master (May 7, 2009)

l88m22vette said:


> Heat retention = heat soak, its not as pronounced as an intercooler but still matters, and using steel piping as pictured means longer retention. There is plenty of info about how a cold-air intake does actually add a few hp to a turbo (because of higher air density and/or flow), and most of those are silicone or composite. If he wants to do it why not just sweat the details now and be done with it, he sounds detail-oriented, worrying about 1% here and 2% there adds up.


The point remains, every material that could be used for an inlet will absorb heat. Metal doesn't just magically absorb all this heat that the silicone won't. Metal is a good conductor, which means it absorbs AND dissipates heat at a higher rate than a poorer conductor, in this case silicone. Either material will have high volumes of ambient air rushing through them at high velocities (if we are talking about peak power capability at all times), which REMOVES heat (that will be there regardless of the material) from the inlet. The retention you speak of is after the engine is shut off, or when the vehicle is stopped, when there is no airflow through the bay other than what the fans can move. Neither of those situations matter in peak power. Cold air intakes don't add HP to a turbo because they INCREASE the drag required to pull air from way down in the fender where they place the filter (on a 1.8T at least, with the turbo on the back of a transverse motor). http://www.autospeed.com/cms/article.html?&title=Eliminating-Negative-Boost-Part-1&A=0629 is an old but good read on the subject. And lastly, none of use are casting our own silicone molds, and making some Home Depot inlet with bends and reducers and multiple couplers will not only look like crap, but not offer the flexibility of a custom made piece. It's much easier to find someone who can cut and weld metal than coming up with your own silicone/composite inlet. You install your BT yet? :screwy:


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