Questions....

[oversteer180]

My friend bought a ca18det, he is using the stock harness and ecu, and just going to use a ecu retune for his upgrades.

He has some 2nd gen blacktop 450cc dsm injectors, we already installed these. Will he need anything special like the dsm resistors to use them, or can he just use them with the ecu retune?

I was told the 90+300zx cas will work in place of the ca18det one, is this true?

He has my old setup(sr t25g, 450cc injectors, 3' exhaust, and fmic.) Will he need an upgraded fuel pump with the retune?

What kind of power could he make using this stuff with a retune?

Thanks alot!

[ccasey645]

fuel pump wouldnt be a bad idea, probibly needed for boosing over 12psi theres some members on the ca fourm that burn eproms i think they do it for other people too would be alot cheaper

[oversteer180]

bump

[oversteer180]

?

[oversteer180]

answers?

[dattodude]

a VG CAS will have only 3 signals coming out because it's a 6 cylinder, and would use wasted spark ignition.. No, you cannot use that CAS, if you were putting a new trigger disk inside because you were fitting an autronic, then it might be possible to use it.

As for injectors, using 450cc injectors immediately means going for an aftermarket computer, unless you can get one of piggy back computer things.

To test if an injector ineeds a dropping resistor, get a multimeter and measure the resistance across the two terminals on the injector.

If about 2.5 Ohms -> Then you do need a dropping resistor pack for the factory ECU.If about 13.5 Ohms -> Then you do NOT need a dropping resistor pack for the factory ECU.

[rexhunta]

wouldn't be the other way around ? anything under 4 ohms DOESN'T need the dropping resistor, anything over4 ohms NEEDS the dropping resistor to drop it down to 4 ohms ?

[dattodude]

No..

I measured several CA18DET injectors = all were 2.5 Ohms.I then measured some RX7 Series 5 550cc ones that I know don't need a dropping resistor, they all measured 13.5 Ohms.

Re-read my post...basically injectors are expected to be at 13.5 Ohms, if they aren't, the resistor pack brings them up to 13.5 Ohms (Or thereabouts)

It's good advice from solid research.

[rexhunta]

No..

I measured several CA18DET injectors = all were 2.5 Ohms.I then measured some RX7 Series 5 550cc ones that I know don't need a dropping resistor, they all measured 13.5 Ohms.

Re-read my post...basically injectors are expected to be at 13.5 Ohms, if they aren't, the resistor pack brings them up to 13.5 Ohms (Or thereabouts)

It's good advice from solid research.

wasn't an attack, i was asking.

so if you take the resistor pack out, you can run a higher impedance injector ? or will the ecu **** itself ?

[UMS_CA18DET]

a Low Imp is any injector under 4 Ohms they require a resistor pack because the voltage to the injector which is around 13.5 Volts will actually burn out the injector.

A High Imp injector is anything over 10ohms these dont need a resistor pack because it has the built in resistance so that the voltage doesnt burn out the injector.

If you are running high-impedance injectors (greater than 10 Ohms), then set the: PWM Time Threshold to 25.4 msec, and the PWM Current Limit (%) to 100%.In essence you are disabling the PWM mode. This allows full voltage to the injectors throughout the pulse widths. For low-impedance injectors (less than 4 Ohms), you need to limit the current to avoid over heating the injectors. To do this, there is a period of time that you apply full battery voltage [peak] current, then switch over to a lower current-averaged [hold] current, i.e. peak and hold. Alternatively, you can add resistors in series with the injectors.

As for the ecu, its configured for low imp. so it has different settings which are needed unlike High imp.

[Kouks]

so the DSM 450s are low impedance as well? also great explanation, I understood it. Second, I actually learned something! YAH!

[oversteer180]

So I will be able to get by with no modification? Just use the stock ca18det dropping resistors, and an ecu re-tune for the injectors?

[UMS_CA18DET]

yup shouldnt be a problem,