Lockjaw

An S trim is a compressor wheel, and a P trim is a turbine wheel, just for starters. Make sure you don't confuse the two. The advice on the turbo from Tim is good. Rotaries typically run a larger AR turbine housing then a piston engine. They have three power pulses per revolution if that helps you understand why. Just so you know, N, O, P and Q trim are all turbine wheels. S and V are compressor. Also Stage III, IV, and V are turbine wheels. You could probably have the stock turbo upgraded by sending it to one of the better shops, like Forced Performance. I am not sure if they do those or not. Alex on here also can build a turbo, but I don't know if he messes with those. He rebuilt one for me and did a nice job, so I would use him again.

What are your turbo spec's? I had a .48 ar turbine housing on my ZX when I bought my first Hybrid, and it rocked down low. I was running a stage III turbine wheel. I did feel like the engine nosed over somewhat in the upper rpm's, but it wasn't to bad. If you do your homework, the .63 works just fine. You need a good stout wastegate actuator, the stock one sucks. I have a dual port one from topend performance, and it really made a difference. Plus it is adustable.

If you bumped up your compression a little by say milling your head, you could run a longer duration cam without much if any loss in power. I would not go thru the trouble of replacing a cam with one with stock duration. Topend Performance has an ITS cam that has a little more duration then stock. It is a cheater cam. If you want a good mild cam, why not get the comp cams 260 for the Z car engine. It is not very large at all.

I would have had the crank shaft balanced, and the flywheel and pressure plate. When I had my engine built, the machine shop balanced everything from the dampner to the pressure plate. I would think with your record that you would need everything balanced to the Nth degree. My engine is very smooth, and I know they had to take material off the crank to make it right. I also have a colored dowel on the flywheel and an indicated dowel hole on the pressure plate, and welded material on the pressure plate. I know from reading something that even a small imbalance is a huge weight issue as the rpms increase. Just something to think about.

Maximun Boost is good but I think Corky is a little conservative. Read it to get a good idea, and then ask questions here. There is enough knowledge on the board to make sure you get it right.

I got a sport 450, but I am not running yet. That is the turbo JeffP was running. He made 413hp with it to the wheels, and the 50 trim is good to 390 or so at the wheels on a DSM, and they say the 60 trim will go another 25 wheel hp over the 50. A 60-1 is a good wheel and it flows a lot of air and would be a good choice, and should not affect your spool up time very much if at all. It is pretty much a myth that the compressor wheel contributed much to lag, it doesn't weigh anything. The turbine wheel has the most dramatic effect. Just drop to a t3 turbine wheel and see what happens. My former turbo was at full boost by 2800 rpms, and on the dyno made boost as low as 1800 rpms. The stage 5 wheel doesn't spool that fast, and it is laggy on a 2.0 liter DSM, but it has 10 second potential. If you upgrade go to the 60-1 and don't look back, trust me you won't be disappointed.

The conquest intercooler sucks. I lost 5 psi. Perhaps enlarging the inlets would help, never tried that. Try the griffen from Raod Race Engineering. In and out on the same side, and not that pricey. I am running a spearco 221 and will let you know how it does when the car is up. The griffen is similar, just not as thick. BUy a good intercooler and be happy about it. [/code]

Put it after the intercooler before the TB, that way the air you vent is cool air verus the hot compressed air coming off the turbo. Not that it will make a huge diff, but you never know.

What kind of car are you putting the turbo engine in, the 240? If so you should only have one relay, the green one, and it should stay as is. I made a connector to hook up a turbo efi harness in an NA ZX, but I don't think that applies to your situation. I have a ZXT at home, and it has a Nissan ECU, just not a stock one. HEHE

James has a twin turbo set-up and I am sure he likes it, but from the standpoint of simplicity, I would just run one turbo. You can swap the engines, they bolt up the same, but you would need to swap over the turbo EFI and that is not quite as simple. Its not to hard, just not simple.

Buy a spearco. I am not a fan of any "stock" intercooler. The Starion one sucks, unless you don't mind 5 psi of pressure drop. Or you can get a griffen from Road Race Engineering, they are not to expensive either.

A 50 trim is a good wheel and you should be able to reach more then 340 hp. You may need to work with some tuning to pick up some power. Why did you back the timing down rather then just adjust the fuel curve? I would think you need more timing.

If you intercool it, you should be able to run 13 flats or so, perhaps better. Without an intercooler I ran 8.70's or so in the 1/8th mile in my old 240, so I bet that would work out to be high 13's. All I know is it would put it all over a 5.0 mustang.

Ross pistons are nice. I have a set in my engine, and they were nice units. 5 years with no problems.

On a stock ZXT HKS claimed 245 hp with thier exhaust, airfilter, and intercooler running 11-12 psi on stock efi. I am sure that is crank hp. You will be pushing the limits of the stock turbine trying to get 300hp out of it. I tend to agree with Alex in that you need to upgrade your turbo, and can attest to his work. I would also spend the money on a good intercooler, like a spearco or a griffen from RRE. You will need a good cooler. You can also run a rising rate fuel pressure regulator, but you need a really good fuel pump to make that work. Cartech has a peirburg which works well with their regulator, and can handle high pressure. I am not a fan of the larger injectors and adjusting the AFM.

You can turbocharge the ZX engine, but you should probably run the turbo electronics at minimum, and you will have to change the distributor drive shaft too. Be careful with boosting it to much though, the ZX engine does not have a piston designed for boosted environments. The cams are also different, and you need one with a B, J or M stamped on the back. J is 81-82 manual, B is 81-82 auto, and M is 83 manual and auto. Any will work. I have the B cam and like it, but could not locate a J cam or I would have tried it just to see if there was a difference. I have seen the specs and they are all pretty much the same. You need larger then stock(turbo) injectors to run over about 11 or 12 psi, and a good fuel pump. I would use the factory nissan headgasket if you swap heads, or you can spend the money on an HKS one if you like.

I like Steve at Topend. He answers email promptly, and will match price if you find things cheaper. I bought my Spearco from him and he matched the price I found on a DSM website, and sent it out the next day. They also built a waste gate bracket for their dual port wastegate actuator for my last turbo, and did nice work. I paid 150 for the bracket and the wastegate actuator, and it has worked flawlessly. Sunbelt is good but the are pricey. Robello is good too. Good work is not cheap, no matter who does it.

I have 240 rods in my 280ZXT engine, and had pistons custom made but was a little off on the deck height so I had to deck the block. I did that mainly to help improve the rod to stroke ratio to help with detonation resistance, and I was able to run close to 19psi on pump gas with flat tops 10 thousandths down in the hole and 1mm over. I polished mine, had them shotpeened and bushed for floaters, had the two oil holes drilled in the small end, and used ARP rod bolts. So far the engine is going on 5 years of abuse with no failure. When I get it back up and going with the JWT sport 450 and Spearco intercooler with 2.5 in plumbing I will post some numbers. I think the L18 rods are longer too, not sure though. Either way I turn mine pretty tight, and with 3.90's in the back it stays on the rev limiter in the first 3 gears (7000rpms). This guy Jack at Scorpion racing, who got all the electromotive stuff told me 5.7 inch rods were the secret to making a Datsun engine make alot of power. Not sure if true or not, just relating what he told me.

Peirburg from Cartech flows 200 liters per hour, comes incased in rubber and is quiet and can handle high pressure levels too. Paid 200 bucks for mine. Fits in the stock fuel pump bracket too.

Don't forget you need to have that all rebalanced, or you will have a shortlived noisy turbo. I would want a bigger turbine wheel then the stock one too. Way to many blades compared to modern designs. My t3 hiflow turbine wheel spooled very quickly and will support the horsepower a 60 trim compressor will make. Good luck

No difference that I am aware of. Have you tried Delta Cams resurfaced rockers? I ran a set in an NA head with a new cam and they were very queit with no unusual wear. I am going to run another set on a cam for my turbo ZX to, just haven't gotten around to installing it yet. Want to see what the car runs like after my latest mod's before swapping the cam.

Jeff that looks really nice.

My last trip to the track was with 3.90's versus the stock 3.56's. On a sick turbo I still dropped a tenth of a second over my fastest time before, this during an 85 degree day versus a cool night. I was all over the rev limiter at 7k on the JWT box in the first 3 gears. I am sure with a better turbo and cooler temps I would have dropped more.

I dropped 8 tenths of a second and picked up 8 miles per hour going from a sucky 2.5 in set up to a 3 inch mandrel bent exhaust, all other things constant, so do the math. 2900 pound car without me in it. Biggest bang for the buck of any mod I have done to a turbo Z car. I agree with the 60-1 and use either a stage 3 or 5 turbine in a .63 ar housing and you should make plenty of power. I would do the exhaust and upgrade the turbo before doing the cam. The exhaust will improve your spool up too. Do the exhaust first, it will be the building block for everything else. trust me, you won't regret it, and run a straight thru muffler like an ultra flow or a Hooker max flo.

You can get resurfaced rockers from Delta cams, I think they are about 4 or 5 bucks each, the downside is you will have to run a slightly thicker lash pad or double check your geometry to make sure you are ok. I tried a set on a crower cam, and they are quiet, and are not giving me any unusual wear patterns. You send them yours or pay a core.