DOC Race RB Manifold Install S Chassis GT42R~

While earlier this week VIP Performance installed the D.O.C. RB Topmount setup on there R34 and were working on the fueling issues that occured, we wanted to address the S chassis fitment for possible wastegate options on our Open T4 and also Twinscroll RB manifold versions. James brought his Nissan 240sx (S13) chassis down that has the RB25 engine in it so that we could do some fitting.

There is ample room in the S chassis bay considering shock tower location and even brake master/booster clearance, which sometimes gets tight with the traditional KA24DE and SR20DET topmount positions. For the wastegate options we offer Dual gates on our Open T4 manifold and also wanted to have a nice single MVR fit for the left-hand drive vehicles with a properly sized turbocharger not needing as much duty. In fitting the wastegate layouts we also fit the S chassis with a GT42R turbocharger for anyone looking to go into the 1,000 horsepower territory…

Everything has a great fit and a nice channel for the downpipe to be routed. When running a larger frame turbocharger like the GT42R, the S chassis has a very small opening to consider a 4″ Stainless downpipe which is standard on such a turbo. We managed to build a full 4″ system on the DOC Race S13 that has the SR20 engine; but we decided to do so using 4″ Stainless Oval tubing for LHD steering shaft clearance and mainly for ground clearance since the 4″ oval measures out to a 2.5″ height when mandrel bent into it’s oval shape..

Finishing up final fitment our “GTR” wastegate outlet design that tucks the gate down low, we pulled the steering shaft joint as high as it could go and also rotated the steering rack into the position with the least clearance for tolerance measurements…

A few more adjustments and everything was finished up for the last gate position. All of these variations are available at the DOC Race Store including the Skyline chassis’!


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