New Message on Nissan/Datsun 720 Pickup Owners
Anybody ever try Turbo charging a Z24?
OK, you can turbo a Z24. How long and how many ounds would be questionable. First off, the Naps-Z head works fine with a turbo. If you can find the coveted Z18ET manifold then you canuse any T2 flanged turbo. A garrett T25 from an SR20DET will work fine. If you can't find a manifold, my company can make a one-off (go to www.fastandfuriousperformance.com
) Piping is academic, route it where you want to go. I personally feel if you are going to go to the trouble of turboing a Z motor, at least figure out how to intercool it as well. An intercooler is well worth the money in the long run. Mounting it goes along the lines of "where in the ...." A top mounted intercooler is a possibility too.
As far as engine management, carburetor won't do unless you have a blow through type. Bowl vents are configured differently as well as some other things. Fuel injection is best, by taking the 200SX intake manifold and using a miscellany of parts you can cobble anything together. This is where I come in, but there is a lot to talk about in that department. Best by far is to have some form of digital programmable stand-alone system. Injectors for the 200SX stock rails are nothing to write home about unless you fork out the money for 280ZX injectors. A custom fuel rail may prove to be the best alternative on a Z injection hybrid as it was in my setup. By making a custom rail you can tailor the rail to the injector you plan to use. My suggestion would be somewhere in the neighborhood of 550cc/min.
Alas, the bad news is in the motor. The Z series pistons are dished out and deliver a pretty low compression of 8.5 - 8.3:1 but they are cast not forged. This ends up being the weakest link aside from the well documented head gasket problems of the Z24. In my personal opinion (remember this is my opinion you can disagree!) the Z24 would be the last motor I would turbocharge. The cylinder spacing is so thin and aftermarket pistons are a bundle. Not to mention that an MLS (multi-layered steel) head gasket is not available. Even if you get forged pistons, you will max out somewhere around 13psi where the head gasket will definitely give out.
That said, remember that the KA24 uses the same cylinder spacing as well as bore and stroke. Special forged KA24E pistons can be fitted to a Z block. With the correct forged internals and MLS gaskets, KA-T's are putting some serious boost to the ground, but also with some benefits that the KA series has above the Z-series.
I have seriously considered a turbo for my Z24E and have decided against it. That said, if I were to turbo a Z series, it would be a Z22. The blocks hold up better, there is more space between cylinders and the Z22 is closer to square bore and stroke than the Z24. Pistons, again would be a hard part to come by, but at 14 psi on a Z22ET, you have a motor that will put down very close to a Z24ET, with the benefit of longevity. Especially if the motor is built right.
Of all the Z motors, I have had the best luck with the Z22 and comparing the Z22 and a Z24 both carbureted and both entirely original, the difference is pretty minimal.
\(power recored below is at the flywheel SAE net)
Z22(S) 98hp @ 4000 rpm
Z22E 102hp @ 4200 rpm
Z24(S) 103hp @ 4800 rpm
(power is on a dyno at the wheels)
My Z24E 124 wheel HP @ 4900 rpm 157 ft-lbs @ 3200 rpm
Z22ET (if it were built with 10psi boost and a 8.5:1 compression ratio using a garrett T25 turbo from an SR20DET
my estimate: 175hp @ 5600 rpm