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With the MAF and Injectors addressed the turbo was next. We chose to upgrade from the T28 to the GT28RS disco potato turbo. We knew that this would require some modifications to the piping as we were running the original Hot Shot T28 kit. This will not be an issue for people who purchase the Hot Shot kit now as they have upgraded to the GT28RS turbo and changed the overall layout of the kit itself. Given that we were also installing a Koyo radiator at the same time as the rest of these parts, a decision had to be made about how to route the turbo outlet. Given that the Koyo is much thicker than the stock core and the new turbo configuration has the turbo outlet pointing downward we knew it was going to be a tight fit. With this we decided to have Jon at o2induction modify the turbo outlet. Jon cut the original coupler fitting off of the end of the compressor housing and welded a cast aluminum elbow in its place. Jon took the time to do it right, cutting the elbow and machining a new coupler fitting for the elbow. He also machined the inside of the elbow so that it is essentially one large flowing piece coming out of the turbo. Once this was done the turbo was assembled. Given that the wastegate is set to about 14 PSI right out of the box we modified the actuator to get it to open at 11 PSI. We then clocked and installed the newly modified turbo. With this done we could now cut and re-weld the original Hot Shot IC piping and also fabricate a new turbo inlet.
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| The new turbo outlet, notice the machined end in place of the typical bead roll? | Shot of the detail work inside, nice and smooth! |
The hot side of the Hot Shot piping was simply trimmed and the original bead rolled end that we cut off was angled and re-welded back on the pipe. This new piping configuration removed almost 30” of intercooler piping when compared to the original layout. The cold side of the Hot Shot piping needed no modification, nor did the down pipe. As for the turbo outlet (commonly called a J-Pipe) it simply needed to have one of the bolt holes enlarged. The turbo inlet required a 3” 90 degree bend and a 3” cast aluminum elbow. We also welded in fittings for the Bypass Valve recirculation hose and the crankcase breather hose. We also upgraded the turbo coolant lines from our previous setup and changed the oil restrictor from a .060 fitting to a .035 fitting; this was done because ball bearing turbo’s require less oil than conventional journal bearing turbos.
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| Inlet pipe with machined fittings. | New inlet installed. |
While everything was torn apart we also installed a Koyo Radiator a must if you are even considering spending any time on the track. The Koyo is roughly 3 times as thick as the stock radiator. We also chose to use pusher fans mounted in front of the radiator to free up space in the engine bay.
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| Small difference in core thickness? |
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| Dual pusher fans with quick disconnects. |
