I want to upgrade to a set of 720cc injectors for the primaries and secondaries, while keeping the price relatively low. So what are my options, what injectors are compatible as bolt ins if any from other cars? Also they must be high impedence, which makes it difficult to tell if certain injectors will work or not, is there any way around having to use high impedence injectors, or anyway of knowing which injectors are high impedence to begin with?

 

The easiest way to tell the impendence is to run an ohm meter across both leads to the injector and see what it reads. If it is around 3 or 4 ohms they are low. If it says 13 or 14 or something to that extent then they are high. You can use low impendence if you have the resistor pack from an '87 or '88. I actually have one I don't need. Don't upgrade the primaries with the stock computer. It will run too rich. It will work on the secondaries though. Oh yeah other injectors need to be modified slightly to fit. Some companies modify the fuel rail for $100 to make them work but I know how to modify the injector for free. Still works too. My 1600cc secondaries on my T-II use the factory unmodified fuel rail.

 

Care to share the knowledge?

 

My plan is to upgrade the injectors both primary and secondary and use an s-afc to get a good fuel map with more boost. Then I can have more options when I feel like I must have more power. With an S-afc I should be able to keep from running too rich no?

 

I personally don't believe in piggyback type of computers so I don't know how well it would work with the s-afc. I know many guys have it with good results so you never know. It might work great.

 

So to check the impendence you just get your volt meter turn it to ohms put the ground on one side and the positive on the other....is this right

 

thats all. Just make sure the car isn't running when you do it

 

Yes checking the impedence is no problem for me,... but say I want to buy some injectors from somebody, they may have no idea. In general are there injectors from other cars that are known to be high impedence injectors that will fit in the fuel rail and work with the ecu?

 

I'd say just go for the 720 2ndaries, why do you need them in the primaries? turbo upgrade?

 

I'd like to go with 720's for both in case the need for more speed and bigger turbos come into play. Also I have a fuel pump on the way and want to run about 10-12psi. However I have been warned by many that if I reach 10 psi before the secondaries are able to kick in I will blow my engine because the primaries wont really go past somewhere like a 70% duty cycle even using an S-afc, so better safe than sorry is how I feel about it.

Yet on the other hand I have read countless contradictory posts and replies that with a 255 lph hp fuel pump and stock injectors you can safely run 10 psi and maybe even 12psi with stock injectors. Someone around here in albuquerque was running 14psi on stock everything with rb full exhaust, gears, and intake for a good while, but ended up without a motor one night. So right now I have RB full exhaust and intake and I hit at the most 9 psi high into 3rd gear sometimes. i have a fuel pump on the way and would like to hear that it is safe to set my home depot style mbc to 8 psi with these and the fuel pump mod. But I am looking around for bigger injectors nonetheless.

 

rewire pump w/walbro and put in the 720 2nd's, and I see no reason for worry @ 12psi, might want a S-AFC

PRO's would you 2nd this????