If I were interested in buying a blown JDM S4 Engine, what would be the thing to look for to guarantee compatability with low impedance injectors, without wiring in a resistor pack (i.e. drop in injector fitment)?

What would be the build date cutoff for JDM engines?

 

huh? first off most jspec engines (if anything all of them ) are high imp

secondly dont bother spending money on a blown motor you will always loose...... and its one thing after another and last thing you know you have nothing to salvage

 

It doesn't make sense to me that Mazda would just export low imp engines for half a year, and just immediately switch. I would think that Mazda produced low imp engines worldwide, then made the switch afterwards.

But, I could be wrong.

 

theres mazda usa and mazda japan bro..... both are abit different due to emissions and the us department of transportations

 

I know, but injector resistance doesn't really play a part in US DOT safety or emissions regularions, right? Fuel is fuel, and the difference is just the harness, so that, to me, doesn't seem to be it.

Weren't all RX-7's built in Japan, anyhoo?

 

Someone has no idea what they are talking about..

Its all very simple, just take a look at the injectors.. Yes S4 TII USDM and Jspec both came High Impedence and Low Impedence. Look at the primary injectors, and this can be done without even removing any parts from the motor. Simply look at the secondary injectors .. IF the tops are square plug Red/burgundy color they are High impedence.. if they are square plug light purple/ ligt tan color then they are low impedence..

 

Or just stab a multimeter on there as going by colour on a 20 y/o engine can be iffy at best since they can fade with heat and age.


This: Is entirely incorrect.

 

So if I were to purchase a JDM S4 low imp blown longblock from you, that could be easily identified? I guess I'm more concerned that the low imp harness comes with the engine as well. Yep, pretty much shortblock and harness.

 

You won't be using the Jspec harness anyway.

You'll use your S4 NA(3 wires changed) or S4 TII USDM harness.

Getting a Jspec for it's harness is stupid. I use Jspec harnesses for scrap when rebuilding US harnesses.

The reason why most engines are high imp is because they only had low imp for 2-ish years(86-87.5). Then they went to high imp for the last S4 run and all high imp for S5.

Injectors are just injectors anyway. You can use what ever ones you want and then modify the harness to suit them. I'm running S4 high imp primaries and S4 low imp secondaries. All you need is a 6.8ohmx10watt resistor per low impedance injector.

Like said above. You can test mipedance with a multimeter. Around 2ohms will be high impedance and 12ohms is low imp.

 

Yea, I could always wire in resistors for a harness that doesn't have it in line, but I just realized that after I posted that I need to go look for a pre 87.5 US TII harness.

 

I would just be interested in a rebuildable J-Spec core, since I'm looking to rebuild and port it as soon as I get it.

For injectors, I don't think it matters if it's an early block or late block, right? As long as I use a Pre-87.5 US TII Harness, even if the block is an 88, I could still drop-in low impedance injectors without having to wire in resistors?

If that's true, then I probably would only need an Jspec S4 rebuildable core.