Turbo 240SX—Manifold and Turbo

My custom-made manifold. It has equal-length runners and very heavy construction.

The manifold has been on the car for three years and used for only racing. It has not cracked or shown any form of distress.

The manifold mounting plate is made from1/2 inch steel plate and is not warped. You can see the Tial 35mm wastegate and extended oil dump tube.

The problem with a turbo system is the extreme heat it generates. I have said it before and I'll say it again: never underestimate the heat!.

Case in point... the reason this manifold is out of the 240sx is because every gasket has blown out and needs to be replaced. This time, I am not going to use bolts or any fancy CAM locking fastener system.

I bought some high-temp threaded rod stock, threading dies and taps, and metal lock nuts. I am making my own studs and will double-nut them all, then possibly even tack weld them into place. I do not want these parts coming apart again!

Another view of the manifold.

The plotting of my current compressor to see if going to a T61 would be better.

It looks like the T61 is a good choice for my engine... it keeps the engine out of the surge area and has good compressor efficiency at higher boost levels.

The new turbo for 2004. It uses the same T4 H-3 compresser I had before, but now it has a hybrid T4 size .84AR turbine houseing with ceramic-coated P trim Tturbine. This should really help with the top-end flow of the engine.

The new turbine is much larger than the .63AR T3 turbine I was using.

The large turbine that has a 3 inch diameter and a V-band discharge welded on.

The divided tang. This should help spool the turbo up by keeping the exhaust pulses together longer.

One of my fears is that the much larger turbine would be turbo lag, but after the insanely quick spool up of the .63AR T3 that I used to have, I'm willing to sacrifice some lag for better top-end flow.

The turbine is now about the same size as the compressor.

The old turbine (left) and the new turbine (right).

The old, stage 3 turbine shaft, which got pretty hot near the end of its life (as shown by the blue tint).

I got three years of racing out of it, so it was well used.

The new, custom-ground turbo cam.

It has 451 lift and 276 duration. This cam, in combination with a new, larger turbine section, should really open up the top end of this engine. I am estimating a 15-25RWHP gain from just the cam and the new turbine section.

I finally gave in... after 14 years on the old 240SX it's time for some updates on the looks.

So, here is a new bumper. The car will also be repainted a really high-gloss red and a totally black roof.

The side skirts... I guess I will see how long they last on the race track.

The brake duct system I am putting in the car when the new bomex nose is attached.

I have various brake duct inlets, and as you can see, I will be using dual aluminum spindle ducts with 3" diameter brake duct hose. These spindle ducts attach closely to the brake rotors and spray cool air from the nose of the car under speed, over the rotor, cooling it dramatically. Most NASCAR and circle track cars use this type of system.

Again, never underestimate the heat created when road racing. Driving on the street and road racing are vastly different things.

This very aggressive brake duct system allows me to block off one of the ports, depending on how cool the rotors get, allowing me some flexibility.

The newly ceramic coated manifold.

I had it coated to keep down the engine bay temperatures. This is a special coating that originated for use in aerospace applications, and is rated for 2000°F continuous usage. Hopefully, this will help put an end to melted ignition wires, distributers, master cylindars, and other things near the manifold that have melted in the past.

Now that I have a shiny new turbo and manifold, it's time to attach them together.

This time, however, I never intend to take them apart or have any loose bolts or leaking exhaust. So I am making m own 7/16 stainless steel studs, and I am going to use stainless washers and nuts as well.

After cutting the threads to size, I re-threaded them so that there are no burrs left from cutting.

The complete hardware, ready to go into the turbo.

The studs installed into the T3 manifold plate.

The turbo mounted to the manifold.

My last effort on trying to keep the studs and nuts from coming loose.

I used stainless mig wire and welded on steel rods from nut to nut, preventing them from backing off. Before I did the welding, I heat-cycled the studs and nuts for one hour, cool to red-hot, then retorqued the nuts.

If this does not prevent the nuts from coming loose under race conditions, I just give up!

Now that I have my wonderful new .84AR turbine installed an mounted, I found out that it interferes with the master cylindar.

So, now is the time to upgrade the braking system, since it was getting melted anyway by the extreme heat from the turbo. So, out comes the brake booster and the master cylinder.

Me, measuring the space I have for an aftermarket brake pedal and master cylindar assembly.

I will most likely go with a floor-mounted Tilton or Willwood setup, with dual master cylinders and bias control, with remote reservoirs.

The 240SX with the stock bumper removed and the new light cover installed.