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Component Matching #4
Page 3
The Houston pipes utilize an integral waste gate. The Turbonetics utilize an external gate.
This is a matter of personal choice since the appearance is very different between the two. Cost is also a factor. When choosing an externally gated pipe like the Turbonetics design, the additional cost of the gates must be figured in. The Delta gate controller is also an additional cost and must be used for external gates.
The Houston pipe with integral gate can be controlled by a simple bleeder, referred to previously in these articles.
When comparing prices keep this in mind since it may appear on first look to be less expensive for the Turbonetics style, This is not the case when you add the cost of gates and controller.
I like the Houston style pipes for several reasons, one being the more conservative cleaner appearance.
The final part to this article on exhaust is headers and Crossover. The crossover pipe should be considered a part of the headers. The crossover pipe is sometimes used to mount an external waste gate. These are mostly used as a second gate when a single gate becomes insufficient to control the boost. Generally this occurs late in the modification process when engine power is greatly increased. The capability of a single gate can be determined by the presence or absence of boost creep at the big end of the track.
I have used the stock headers on very powerful cars. The capability to run into the 10s with these is uncontested.
There are some considerations here. The stock headers are made of stainless but not a very high quality. These do have a tendency to crack at the three / five crotch. If yours is cracked it will make a sound like a clicking from that area that you can hear at idle. It’s difficult to actually see since there is a heat shield in place and it is pretty deep under the engine.
If you hear this and want to have it checked out, you should only have this done by a qualified TR technician. There are plenty of things that can be done by your local service people, but unless they are very familiar, good and careful you may be in for difficulties.
If this repair is attempted it should be gusseted. Once the driver side header is removed and the heat shield is out of the way. That area can be ground clean and welded. This should be done with the header bolted to a head, to keep it true during the otherwise possible deforming process due to the thermodynamics involved with welding. Once it’s welded, if it’s not true there will be problems. At this point the gusset should be welded in place. This should be a piece of material roughly triangular, that fits into the crotch area. This will strengthen the area enough to avoid future cracking, which can occur if not gusseted.
There are alternatives to this repair. There are some aftermarket headers that are relatively inexpensive and do look and perform better. I’m inclined to use the stock ones since they can be repaired and are not a significant source of performance improvement until you reach very high levels.
If you choose to keep using and repair your stock headers, there are some slight performance improvements that can be made with porting and aligning.
There are a number of companies that offer ceramic coating of our headers. Our headers get very hot compared to normally aspirated cars. This is a source of concern if you are considering getting them coated. The only choice in my opinion would be the very high temp product that is only offered by one company that I’m aware of. This is advertised at a heat range number that I have no way of verifying so I won’t quote it here. The Brochure states that this coating is only available in the darker grey color. The possible advantages quoted are lower under hood temps and hotter exhaust gas temps to aid in turbine wheel speed for spooling. These are claims that I can’t confirm or refute.
I can say that I have had a customers car apart recently with the lighter colored coating that was rated at a lower temp. This coating was undeniably not able to stand up to the application.
This concludes the exhaust portion of these articles. In future articles look for traction, suspension, torque converters and turbos.
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