STI Element Hydra Greddy T67

This was tuned on a Dynajet in Miami, Florida at Twilight Performance.

This was a 05 STI with and Element Hydra STI and a Greddy T67 Turbo Kit on pump fuel. This setup turned out very well as it was quick to spool up and very responsive. This really makes for a great street car. Boost pressure was 20-21 psi and the AFR was right at 11.0:1.

We saw 20 psi as quickly as 4100 RPM. In the world of 375 to 400 whp pump turbochargers I consider decent. We were having some issues with regards to the blow off valve giving us slightly inconsistent boost response. We could actually here the blow off valve snap shut on occasion. At times we didn’t see 20 psi until 4500 rpm but once the headers were hot the spoolup was generally good. It was so hot in Miami along with a really poor fan system, made it difficult to get a dyno pull in with the car less than 92C on the coolant temp. This means it was rare that we got a run in with a warm header.

I was surprised to see that Greddy uses a relatively small 8cm exhaust housing which limits peak power but the trade off is great boost response. I think for many this will be a fair trade. We know the exhaust housing was choking power as increasing boost pressure didn’t net the gains I’m used to seeing. We maxed out in the mid 390s but the tune was too aggressive for pump fuel so we backed it down some. Keep in mind there are different versions of the T67. For instance the EVO kits use a 10cm exhaust housing vs. the 8cm housing on the Subaru kit. I’m assuming Greddy went with the 8cm housing as the JDM cars are mostly 2.0 instead of 2.5 ltr.

Phil Grabow

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