What's it going to cost? RB25DET.

So, the RB20 is a good entry level Nissan 6 cylinder, but what's the next step up? The RB25DET of course.

So this is the RB25DET and this is a typical ad. Like the RB20 yesterday we need to read the ad because due to the popularity of the RB25 you will find more people trying to make full motor set money on just an engine, or an engine without an ECU or wiring.

As with the RB20, we're looking for a full motor set with transmission, ECU, UNCUT wiring harness and all turbo/accessories. This one above has all off that. $2200 shipped to our door.

So the RB25 is a little different than the RB20, but not by much. We still need the $500 oil pan. We still need to budget about $500 in maintenance. We still need the $200 Boost controller. There is a few small changes we need to make though.

The over the valve cover pipe on the RB20DET is a great design. On the RB25 it's not. More turbo pressure requires more air and fuel flow. Also, in the interest of only making intercooler pipes once we will replace the intake manifold with a front facing design. Like this.

This does two things. It shortens the charge pipes on the intercooler. Shorter pipes means the air has to travel a shorter distance in the pipes meaning better throttle response and less turbo lag. It also looks a lot better. Cost? $300-400 depending on vendor and if I want it polished or not.

Now that we can use a standard intercooler the price actually will go up a little. Plan $400 for an intercooler with pipes for a good unit.

This might be a little aggressive, but you get the idea.

So now that it's mounted and running, how about our goal?

The RB25DET is rated at 250hp out of the box. By the time we factor in the fuel system and custom exhaust we really don't need much to hit 300hp. Turn up the boost and the fuel and with a careful eye we can rock 300hp out of the box. Ideally, we'd upgrade the turbo while it's out of the car and install a steel wheel.

This company upgrades the factory turbocharger with steel wheels that have been made special. It's not uncommon for people to make 300-350 horsepower at the wheels with stock fuel and engine management. We'll be looking at engine management later this week along with the fuel system that needs to be made. With our fuel system and some tuning we could probably dial this turbo in anywhere between 300-400 horsepower at the wheels. Cost for the steel wheel service? $800.

So, what's an RB25DET cost? $4700-$5500 depending on whether or not we go with the upgraded turbo.

Tomorrow we look at the king snake of RB motors, the RB26DETT.