SleeperZ

Are you crazy??? WTF are you thinking???????? j/k - sounds like it should work just fine, lots of folks parallel pumps, and it sounds like your feed is plenty big.

I run 215/60/14 on my 14x6 wheels, no problems at all. I would think 235s on 14x7 would not be a big issue for street driving. Obviously for all-out track performance, you wouldn't run such a wide tire for the wheel, but I run the 225/50/15 on my 15x7s for the track, which is a very popular Z configuration.

Your mileage is extremely low. Even with stock electronics, you should break mid 20's. I am running a factory Z31 ECU and I get 27 mpg (91 octane, 5000' elevation, averaging 80+ mph). Check your ignition timing, plugs, wires, cap, rotor, O2 sensor, and fuel pressure regulator.

What ECU/airflow system are you running? Is the engine/fuel system/turbo stock? Are you running stock boost levels? Any more information about what you are running will help - any changes you may have made could be important. Do you have good gauges, such as a boost gauge and an air/fuel mixture gauge? These can be invaluable towards diagnosing EFI and turbo issues.

I've heard tell sometimes you don't hear detonation until it's too late. What color were the insulators? If they were close to white, maybe you should try a colder heat range, but I'd not push your boost any more, or back it off some, until you figure out what it is. Ceramic chips can't be good in a (relatively) soft steel engine cylinder.

One word... DETONATION That's the only thing I know of that breaks plugs.

First thing I would get your ignition timing problem solved. Maybe your distributor drive is off a tooth - you should be able to idle well with 20 degrees advance (20BTDC), and it should not waver. Check your idle switch on the throttle body, and make sure it closes when the throttle is closed - this can cause an unstable idle, as the ignition timing will wander with rpm. Past that, you may need a new O2 sensor or a new fuel pressure regulator (both can cause over-richening), but I highly recommend an air/fuel mixture gauge and a fuel pressure check before throwing money into parts you may not need. Once you fix this issue, you can dig deeper.

I appreciate the input, thanks. I shall retain the factory belt to use on the street (it's so much easier to fasten), and use the 5 point on the track or strip - much less chance of an accident there. Of course I am knocking on wood I don't get into an accident on the street; without any bumpers, I don't have much protection (shudder to think about the fuel tank behind me).

Just want to add one thing - not all P90A heads have hydraulic lifters. Mine has regular adjustable ones, so lift the valve cover to make sure.

I don't have pictures, but I used a Ford truck heater valve and adapted the factory lever to it. I'm still using a factory 90* hose to the original metal piece on one side of the core, but the hose from my valve goes straight through the firewall to the engine.

No 280ZX came with LSD. The Z31s with LSD are turbos, '87 - '89. There is some talk I've heard that perhaps a 240SX had an R200 LSD, but who knows....

Hmmmm...The differences you are hearing about are mostly measurement and conversion errors. The flow rate is dependent on the fuel pressure, some folks may test at 37 psi (2.5 bar) and others may test at 43 psi (3 bar). The conversion between lb/hr and cc/min is approximately 10.5, but I've also seen folks use 10.2. The point is, they are approximately 36lb/hr or 370cc/min AT 100% duty cycle, so to determine if they will work for you, you need to measure them at your fuel pressure and if you can, measure them at the max duty cycle of your fuel controller. You can also do it mathematically, just multiply your max duty cycle by the flow you measure at 100%. There is some error due to time lost in movement, but it should be close. Remember, put some margin into your system - if you are running them on the edge, even a minor malfunction can be disasterous. BTW - I measured these injectors to 360 - 370 cc/min at 37 psi fuel pressure, 100% duty cycle.

bump

I'll give you the main reason: It is a much easier conversion to turbo because Nissan made a factory turbo motor and control system that drops in. The only supercharger kit I've ever heard of is the Eaton-based kit from Jim Cook Racing, and it used a Holley injection for only 7 psi boost. Weak, in my mind - won't keep up with a factory turbo for twice the cost. Keep in mind turbos are so much easier to upgrade with intercoolers and bigger turbos, and the Nissan L28ET can do 400hp stock.

I came upon a Porsche 911 with a blown motor I will be parting out. It has stock seats, and a Simpson 5 point seatbelt with a "Y" shoulder harness that I would like to put into my '78Z. I just read this thread. racing harness thread I don't have a cage, just a TEP rear strut brace. I'm not sure where to mount the shoulder harness - has anyone got any ideas? It probably is not a good idea to mount it to the strut tower (off center to begin with), and I'm not sure the strut brace is strong enough. It looks like the seat cannot accomodate the belt anyway (integrated head rest), but the Porsche had it installed this way anyway... I don't use my car competetively, just informal events, no real racing, and the belt would be nice just to hold me in better. I probably would not use it on the street anyway. Thanks for your input.

I believe the Nissan truck unit is an R180. Some of these have ratios of 4.38, and none are LSD.

Are you running street tires??!! I have not yet driven that good of a 60' with my drag radials...

Ditto for me

LOL, I hope so. But I bet he could truthfully get 20 more horsies with a better intake, UNLIKE the Honduhs....

Oh good - it's not on a Z (close call!) Excuse me......

Way to go! Next show them what it'll do on the strip

Please feel free to correct if I'm wrong, but this is what I believe to be the correct terminology for the various pieces of hardware hanging on the intake... A BOV (blow-off valve) is mounted between the compressor and the throttle body, and releases pressure when triggered by manifold vacuum (throttle closure). Typically the pressure is released into the air. A "compressor bypass" valve and a "diverter" valve are identical, and function similarly to a BOV, only the vent is typically routed back to the intake on a factory ECU (for emissions reasons). And finally, a "pop-off" valve is a Nissan factory pressure relief valve mounted on the intake manifold after the throttle to release the manifold pressure to atmosphere if it gets too high (factory Nissan vents around 8-9 psi, for margin over stock 5-6 psi boost).

Don't be in such a hurry! It usually takes 4-6 months to get it

You are right - I strayed as I have experience with turbo engines only. I also agree about the flapper door - too restrictive. I will take issue about batch fired EFI - just as good as an expensive sequential. When your RPMs rise over 2000-3000, most factory EFIs switch over to batch anyway - you simply haven't the time to inject all that fuel in the shorter time the valve is open. AFAIK, aftermarket fuel controllers are the same way. No fuel leaks with that stuff.

The most power and driveability comes from FI period. Just like John said. FI doesn't necessarily mean the factory FI, which can be tuned for a large amount of power, but not easily or cheaply. However, my ZT with a factory '87 ECU gets 27mpg on the highway, and puts 230hp to the ground with no driveablilty problems whatsoever. Try that with a carb (blow-thru or draw-thru, carbs on a turbo suck).