alright, i have a 89 t2 and i need someone bigger injectors...i was thinkin 4 x 720cc or something close to taht, but the problem i am running into is my stock injectors are high impedence and all the ones i can find are low impedence....do any of u know wehre i can find some high impedence ones??

 

You don't want to increase primary injector size on the stock ECU. It can cause flooding and idling issues.

You won't find any high impedance 720CC injectors. All large injectors are low impedance. Just put a 10Ohm 10W resistor in series with each injector.

 

not to steal your thread, but i drive an 87 TII and am looking to put in 720cc secondaries with an Rtek 1.7, would i need to put a 10 ohm resistor in too? does it matter which lead it goes in series with? or do i put one on each lead?

 

the s4's use low impedance signals so no you shouldn't have to.

 

Only SOME series four use low impedence injectors. Learn something new every day, don't we?

Rotary Performance sells injectors and the resistors: http://www.rx7.com/

 

where would i get these resistors?? and would i need them if im running a microtech lt8?? or could i just program it in there without puttin the resistor in?? im a complete noob when i comes to the electrical components of the fuel system...where are these resistors??

 

i thought the 88 and later models uses hi imp. and 86-87 uses low imp.?

 

yeah...thats what he is saying...i need low impedance injectors for my 87 TII...thanks...ill search the forum cause i only wanna spend 150 max for both injectors...

 

half of the 87 year uses high impedance...

bet ya didn't know that...

 

Any danger if you run bigger secondaries without the resistors? I am not sure exactly what the difference is with high impedence vs. low impedence. Not too electronics saavy.

 

thats no good...how do i know if mine was the half with low or with high?

 

but the 88 is a s4 also.....right?

 

High impedance are generally called "Saturated" and low impedance are generally called "peak and hold".

The FC never really ran in any other mode then Saturated, its just the location of the resistors was changed (probably to save money). Saturated injectors, and Peak and Hold injectors with a resistor look about the same electrically to the ECU.

If you run low impedance injectors with no resistor then you run the risk of frying the drive circuts of the ECU.


On a side note, alot of ECUs (to include the Haltech E6K) can run low impedance injectors in Peak and Hold. This gives a faster response/rise time and provides a better performing injector.

Rat

 

Any electronics store will carry the resistors.

You will have to look at your existing injectors to see if they are low impedance, or look for the injector resistor pack under the airbox.

Doesn't matter which lead the resistor goes in series with.

 

Does this mean if I fry those circuits, my injectors won't work properly? Any danger of blowing my engine as a result of fried drive circuits?

 

Well, there are some that have ran low impedance injectors on the stock ECU with no resistors and got away with it, some havent. Its your choice.... Do you want to risk possible damage at the price of some 2 dollar resistors?

 

That is a good point about the resistors. I'll have to look into doing that. Will my friend know what it means that they need to be wired in series? I know I don't know what that means...One friend works at radio shack and the other claims to be fairly knowledgable when it comes to electronics. Or should I just read about it and do it myself?

Also, is there any advantage to having low impedance vs. high impedence injectors in general? Are the early s4 guys better off than me. I have an 88TII. Just curious. I don't mean to thread jack. This is good info I think. Unless, everyone already knows all this stuff and I am just a moron.

Thanks in advance Rat.

-Greg

 

This place sells the resistors at 10 bucks a pop. No, I never bought any.

I'd suggest getting the solenoid resistor package out of a old 86-87 1/2 car and use them. Some thought required if you do it that way.

 

This is where I got my secondaries from. My mechanic ordered them so I am pretty sure they are high impedence already. Anybody else bought injectors from them?

 

i forgot the URL http://www.rx7.com/

 

i got RC Engineering 750cc secondaries in HIGH impedance, they do exist