Which direction to go for fuel/timing/ECU/etc

[Mycarispurty]

I'm looking at picking up a local'ish 75 280Z with an 83 swapped turbo motor.  As far as I can tell the entire drivetrain was swapped over along with the stock ECU.  The guy isn't really much of an import guy so he doesn't know all about ECU tuning, injector upgrades, good turbo choices, etc, he struck me as more of a good ol' boy that'd be more familiar with domestics and such.  One reason he wants to sell it is it pretty much has reached its limits unless lots more money is invested, money he doesn't have.

 

Anyways, the car fires up and runs and drive and idles fine, but falls on its face, he says at 5k'ish RPM, but when I drove it today pretty conservatively, it wanted to fall on its face at 3700'ish RPM.  But I also only "got on it very lightly" one time.  Under basic highway speed driving, it ran fine.  He has a huge Chinese t3/t4 turbo on it he got from a buddy's 4 cylinder Mustang with who knows what a/r ratios, internals, etc.  He also has a FMIC on it, and a Walbro fuel pump, but the rest of the engine setup is stock.  So it has stock fuel injectors, stock rails, stock pressure regulator, stock ECU, etc.  The car is pushing too much air for the stock injectors obviously and the rest of the fuel system can't keep up, and his plugs were gapped at 44 thousandths instead of 28ish.  The nice people at JWT told him he's probably blowing his spark out by having them gapped so wide, which could be 1 cause for his problems but obviously not a final solution.  

 

Luckily, perhaps, for the engine's sake, when it runs out of steam, the car hasn't really built any boost because of the massive turbo which probably isn't that efficient anyways, so it's not like it's screaming down the road making gobs of power before the car leans out and sputters.  

 

Here's where I come in: I want to get the car and slap a Pallnet rail on it (and clean up some of the vacuum lines and excess crap while I'm at it), install some good clean Supra 440cc injectors, a good reputable brand t3/t4 turbo and either completely rip off someone else's parts list and use their maps on a Megasquirt, or swap to the Z31 setup and just send the ECU off to be flashed for the mods installed.  I'm familiar with EPROM setups from having a mail in tune on my 300ZX Twin Turbo.  I know a standalone is obviously better than mail in tunes but I kinda kinda just to make it be able to run all the way to redline and make safe, fun power w/o spending piles of cash.  That can come later, I just want to make it proper until down the road.

[dexter72]

To me if your going to do the Z31 setup and get the ecu re-flashed, you might as well buy Megasquirt. You have to pay each time you get that ecu re-flashed, for any upgrades that you do. $250.00 a pop is what i think that runs. The initial costs between the two  will be close plus with megasquirt, you can fully tune your engine and make changes for any upgrades you may do later. You can also take the megasquirt out and install it in just about any other project car you may get. Your not limited to the z31 ecu. If you buy an 8ft megasquirt install harness, you can cut the end off the harness and just use that in another car too. 8ft harness is about 3ft more than you would ever need.    

 

But that's just to me.

[NewZed]

or swap to the Z31 setup and just send the ECU off to be flashed for the mods installed.  I'm familiar with EPROM setups from having a mail in tune on my 300ZX Twin Turbo. 

Are you sure that the Z31 EMS on an L6 can be "flashed" based on a list of components?  Chips or reprograms are typically based on high volume stock setups.  That's where the customers are.  Call the place(s) you expect to do the work and see if they have a clue about what you're using first.

[Mycarispurty]

Well I don't know about that NewZed, just assumed they're similarly mod-able like the Z32 ECUs are, with Nistune or what have you.  I emailed JWT and told them what the car has, what I plan to immediately put on it, and see what they offer with their modded ECUs to see about getting the car running right throughout the entire RPM range.  I don't know what re-flashes for future mods run with JWT or whoever on Z31 ECUs, I just know that most companies in the Z32 world charge roughly $100 for the chip itself (assuming your ECU is already socketed) with whatever mods set on the chip.  If you changed injectors, for example, at a later date to something bigger, then it's $50 for a re-flash of the chip to reflect the changes in the car that the chip was originally programmed for.