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| The center section of the HKS GT3037 here shows the oil inlet; we also opted for water cooling as shown on the top and bottom. |
On the exhaust side of the turbo, the HKS turbine is unique as it has the same flange (footprint) as a T-25 turbo, which is common for factory turbo charging. This makes the GT 3037 an ideal choice as a replacement turbo, provided any fitment problems with the large compressor housing. A .73 A/R turbine housing was used in our application because it flows more than the big T-3 turbine and requires 15-20% less inertia. This size turbine housing has also worked well on other 2-liter Mitsubishi applications. Basic benefits are that this housing lacks an internal wastegate port, which helps clean up the flow in the turbine. It also has a good aerodynamic design that allows more flow for the amount of energy used to spin the turbine. Finally, the diffuser at the outlet of the turbine is tapered for a better transition of exhaust gasses into the downpipe. These are not breakthrough design features, just improvements on what has been produced already; which is always a good recipe for more power.
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| note the rough casting on the turbine inlet. We’ll be sending the housing off to Extrude Hone to reduce turbo lag. |
The turbine housing on the GT 3037 while efficient leaves the factory with a rough cast finish on the inside of the housing like other turbos. Before we bolt this turbo up we decided to send the turbine housing to Extrude Hone.
For those who don’t know Extrude Hone specializes in polishing areas of components that are usually inaccessible to normal areas of machining. Anywhere that air or liquid can flow, Extrude Hone can polish; this makes their process ideal for our application. Extrude Hone applies their “power putty” in the direction of the parts normal flow, leaving a smooth finish. This helps maximize the flow velocity inside the turbine. We can expect that this improvement in flow will help reduce lag by a couple hundred RPM.
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| just try and get a finish that smooth in there with your Dremel tool! |
We then sent the turbine housing to Swain Tech Coatings to get their White Lightening Coating applied. The Swain Coating is a true thermal barrier and is .015″ thick vs. other paint type coatings that are .002″ thick. It is applied as solid ceramic layers and insulates radiant heat, lowering under hood temperatures. Our idea is that this coating will help reduce the chance of heat soaking the engine and prevent engine killing detonation. Once our exhaust manifold is finished we plan on applying Swain’s coating to it as well.
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| Swain Technology’s White Lightening Coating will not only help reduce underhood temps it will also keep the turbine wheel spinning reducing lag |
