More power from stock L28ET

[DuoWing]

Alright guys it's been beaten to death I know. I've been searching and gathering things. I want to know if you guys can tell me if I'm on the right track and if you guys can provide me with an estimate here.

 

Right now I'm running a stock 1983' L28ET with P90a head and auto tranny. Engine has a little over 96k original miles. NGK plugs BPR6ES-11 plugs, NGK wires. Pulled A/C belt, will remove the compressor soon. Blocked off AAC, VCV, still run the air regulator. Stock pump, remanned injectors, new CHTS, fuel pressure regulator, etc. Stock exhaust/downpipe.

 

I've upgraded to a 1986' 300ZX ECU/MAF combo. Then I added Nistune into my 86' ECU and it's running the fuel maps, etc from an 88-89 Z31T ECU. I've also purchased myself a Zeitronix ZT-2 with Map sensor so I can monitor things and tune without trying to do it blindly and destroying my engine. After looking at the Fuel maps for the stock 88, I see high end load has aimed values of like 10.3:1 so I see that just by leaning the maps out some in the high end can pull more power on stock boost/turbo.

 

I got myself an intercooler off of ebay, I'm going to get myself some piping shortly, I'm gathering a blow-off valve and electronic boost controller.

 

Basically I'm wondering what would be the next direction to go? I'd like to get to 300hp eventually, but as a start I'd like to aim for 250hp, then once I hit that go up. From what I've read it sounds like this can be easily achieved on stock boost, I'd also assume with Nistune, and the Z31 MAF setup I should be able to tune my maps and get there alot easier than if I was trying to do this on just a stock efi setup. Basically can you guys direct me as which way to aim ie: how much boost I'd need to run to get to this goal? It sounds like the best upgrades you can do are the T3/T4 turbo, larger injectors, and a larger less restrictive exhaust.

[Tony D]

It sounds like the best upgrades you can do are the T3/T4 turbo, larger injectors, and a larger less restrictive exhaust.

 

Without a ported head or a cam, you simply will run more boost to make the HP---there's where your T3/T4 (GT35? Take your pick...) comes in, more flow at higher boost pressures, and that intercooler.

 

With that air, you will need fuel, so there comes your larger injectors.

 

But probably the first thing to do is uncork the exhaust. 20HP from JeffP's observations on an otherwise stock ZX is nothing to sneeze at, and it helps you down the road for everything else.

 

I'm not sure why you used a MAP sensor for what you are doing though. The MAF will measure flow into the engine. Flow is flow, and it correlates fuel requirements based on flow into the engine. What boost that flow happens at is pretty much irrelevant, you just need to tune your tables to match fuel flows to air flows and go from there. MAP sensor for datalogging should be nice, though...

 

WBO2 setup as well?

[DuoWing]

Oh, the map was more for accurate measurements of Boost. I still have the MAF and everything, the MAP is just so I can keep a log on the boost/vacuum of the manifold along with everything else. Like I said I ended up going with the Zeitronix ZT-2 wideband O2. I figured I'm not about to start cutting fuel off my maps without someway to confirm the A/F ratios.

[Clifton]

I'd like to get to 300hp eventually, but as a start I'd like to aim for 250hp, then once I hit that go up.

 

The first thing I would have done was up the boost to 12 psi. More if you have a wideband and it doesn't knock. That would easily get you 250-300 hp. I would rather spend $10 on a manual boost controller for an easy 250 hp than hundreds on nistune, Z31 ecu, electronic boost controller, ect just to try and make power with a little less boost. As long as it runs on pump gas, HP is all that maters to me.