Turbo 350Z – Part 3

We should only be a week or two out from getting the car started with the new turbo kit, the last few weeks have been a bit of a blur as an influx of cars meant we needed to pump the brakes on the project for a few days and I only got three or four hours of real work completed on the project since I lasted blogged.

This weekend was a different story though, I managed to sneak in a half a day Friday and a full day Saturday. I’ve finally been able to tick the exhaust manifolds off the to-do list once and for all.

After speaking to the guys from GCG Turbochargers earlier in the week we had another change of turbine housing for our kit. We’re back to the twin scroll or “divided” entry T4 turbine for two reasons:

  1. Garrett’s supply of the T4 undivided housing is limited. Apparently they hardly ever produce the stock and it would take a few months just to organise the manufacture of one, let alone us needing a constant supply of them when the kit goes on sale.
  2. The more common of the T4 frame is the twin scroll version, this meaning we have the ability to offer different turbos with our kit if we feel the need and customers purchasing our kits also have the option of upgrading/swapping turbochargers if they see fit.

So a new turbine housing rolled up on the Thursday along with a new turbine inlet flange and outlet v-band flange. We’ve gone for the 1.00 A/R to start with and if we feel we’re struggling with top end exhaust flow, we’ll look at going larger after some dyno testing.

While I was doing the ring around, I thought it would be a good idea to get in contact with our friends at Turbosmart to order a RacePort blow-off valve and 50mm Pro-Lite external Wastegate. They definitely came to the party with giving us an extra special project discount and of course these will be included in future kits we manufacture.

The Raceport is one of the highest flowing blow-off valves in the market which I believe will be ideal for venting that boost between gear changes and sudden off the throttle events. Our 350’s run electronic throttles so the butterfly can shut a lot quicker hence venting the boost quickly is a lot better for our brand new turbo than letting it surge back through the turbo compressor. As for the wastegate, we thought 50mm would be the minimum size we should run to make sure we don’t seen any boost creep at low boost levels/high rpm condition.

So after the exhaust manifolds were completed, it was off with the front bumper and onto the front mount intercooler. We sourced a 600 x 300 x 76mm intercooler and cut it down to suit our application. The core size is a little smaller than i’d hoped for but this should be good for our target power that our stage 1 kit will produce. We’ve also modified the end tanks to allow for a 2.5″ inlet and 3.0″ outlet both returning to the left hand side of the vehicle. We’re attempting to keep the intercooler piping to one side, this will keep the engine bay neat and use the minimum amount of pipework.

The intercooler was positioned quite low to ensure the maximum amount of airflow through the bumper would contact the core’s surface area. I also gave it a lick of black paint for a stealthy appearance when the bumper in reinstalled. We also had no clearance issues meaning no bumper trimming and the factory reinforcement bar remains untouched.

The last item on the weekend’s list was mounting the wastegate and ensuring enough clearance on both sides of the wastegate hat. There’s about 15mm on the chassis side which is more than enough to allow for the engine twisting on it’s mounts. Happy Days.

We should have the intercooler piping, down pipe and possibly the fuel system buttoned up next week, stay tuned!