Hello to all, i'm an old muscle car owner and just bought a 280ZXT. I love driving this car and take it out every nice weather day I can. I could use a little help understanding whether some of the perfromance parts installed by the orginal owner are quality. I have never adjusted the boost contoller to high boost in fear of leaning the fuel out to much. Someone with knowledge could give a few pointers I would appriciate the explaination.
The fuel injestors are upgraded to 420CC and will the 300zx Ecu dump more fuel as needed? What programable ECU would be the best and will the new ECu work withe the current harness?? Maybe a piggy back?? Help and thanks

Oh by the way the complete description of the modifications to the car as purchased are on my profile.

Rick

 

Welcome to ZDriver!

I gave up reading half way through your car description post, so we'll start fresh here.

So right now it's running 420cc injectors with a stock ecu & afm?

You can NisTune a Z31 ecu to run anything you want.

 

My 280ZXT

- new tokico struts
good!
- MSA larger sway bars
good!
- braided steel flex brake lines
good!
- A/c Heat converted to manual type much more relible works great A/C is ice cold heat works great
Nice mod
- 300ZX LSD 3.71 Diff,C/V type axles BW T 5 completely rebuilt with all new japanese bearings and sychros,seals
very nice - the Z31 (300ZX) LSD are hard to get and expensive - great upgrade!
- New center- force clutch all new clutch
good but I suspect it wouldn't hold up to the claimed 400HP
-Hyd parts,lighteded fly wheel, driveline modified with greaseable u-joints custom alum.radiator,nissan factory coolant lines,dual Masarati cooling fans
nice upgrades the guy who had this knew what he was doing....
-custom spearco bar and plate intercooler,with custom air intrapment ducting and a Kand N type air filter,120 amp alternator Race gate T3/T4 Hybrid 57 trim,.63/.82A/R.

I'd love to see some detailed pictures of the intercooler setup. It sounds like you have a very efficiently designed setup if he has it done the way I think he has

- 400HP engine,with JE pistons,total seal rings, ARP head studs,race prepped rods/bushed HKS metal head gasket,completly rebuilt enging,75 non EGR intake JW 300ZX ECU, with 420 CC injectors,New harmonic balancer,For Cobra MAF,Greedy profec b boost control LG throttle body,XS BOV MSD3A custom downpipe and 3" front to rear exhaust Extremely fast and very reliable the black interior .brand new Yokohama Avid Envigor 205/55/16 front 225/50/16 rear Konig 5 spoke wheels

Very nice car and well thought out. It sounds like its a Jim Wolf setup with the Z31 ECU and Cobra MAF. If you are running NisTune its a very good reprogramed stocke ECU and you can tune the fuel and spark map. If you want more flexibility you can always go with a Mega Squirt III ECU and the sky is the limit for tuning. Electronic boost control, sequential injection and spark, NOS, etc, etc. For 400HP 420cc injectors are too small....

 

Oh yea and it's destroying the piston skirts and con rods that will be the issue with detonation if you crank the boost too high not spinning the bearings. Hotrod folklore doesn't apply to the L28 engine. A good place to get some quick info on the L28 over here. With a competant tuner you can maximize the boost and tune safely. You need a steady state dyno. The power is going to come from your spark map and for each cell you'll reach a maximum torque as you advance the spark then it will start to drop off then eventually detonate and knock. A tuner will tune to that peak move ahead and see it drop off and go back a degree. That leaves you a fair amount of safety built in.

I don't know what modded Z31 ECU you have but 420cc injectors are probably too small if you are looking at 400HP and you would probably be better off with 550cc injectors. I'm just not sure what your modded ECU will support.

http://www.rceng.com/technical.aspx

Stock 43.5 PSI (3bar) fuel presure and it calculates out to 529cc injectors for 400 crank HP at 80% duty cycle. Running 80% gives you headroom in case you are on the lean side and need more fuel you've got room and it's not good to run injectors at 100%. This is a conservative calculation but a safe one...

 

In my opinion 420cc injectors are only good for up to about 300hp.

As you go up in size make sure you confirm the minimum duty cycle for your injectors as well but you should generally be good up to about 600cc before it starts to be a problem.