I've searched and searched and can't seem to find any of the answers I am looking for. What is the maximum amount of hp the injectors can handle without leaning out the engine? I am looking into doing a M-90 or M-62 SC system, and am shooting for ~250hp. Will the stock injectors if cleaned and flow tested handle this much power, or do I have to drill 2 new injectors in? If I do have to add a pair of injectors, what size?

I'm sure there are some guys who have the answer to this like Peejay, Directfreak, MikeP-28... etc?

Daryl

 

These are SE injectors, therfore they are over sized anyway and there is no need to put them with any other injectors......yes they will do the job.

 

ok.. so what is the MAX hp on the 13B 6port with the stock injectors? gimme a ballpark so I dont get too close to it. I do NOT want to run risk of leaning out .

 

Injector size calculator:

http://rx7.com/cgi-local/2ndgencalc.cgi

 

For a N/A, max HP at 85% duty cycle with 680's is about 195hp. With 720's, about 210hp.

Max7's research suggests that all '84 had 680's and all '85 had 720's.

With two 440's per rotor (like stock FC N/A) it's about 260hp. With two 550's (stock FC Turbo) it's about 325hp.

Note that these figures are for N/A engines - a supercharged engine will need to run a bit richer for the same HP so you'll want even more cushion room.

 

ok thanks purple and peejay .. so what I should do is pick up a second set of 2 - 680cc injectors and run them as well. Then I should have no problems with too small of injectors right? Will the GSL-SE ECU handle 2 more injectors? If I am planning on getting a Haltech F5 ECU and getting rid of the AFM and running a total of 4 - 680cc injectors, what problems will I run into with boost? Oh, and how much boost do you recommend I run? I am thinking between 5 and 10 psi, most likely near 5 for now. If I was to run 10psi, would I have to advance or retard the timing?
Keep in mind I have the heavy hi comp 9.4:1 rotors. I think 11.5:1 a/f ratio should be sufficient.. right?
Daryl

 

Not directly.

The stock AFM runs out of airflow about the same time it runs out of injector, so if you want to keep the stock ECU you might just want to get a second AFM and ECU.

Alternatively just get a T2 ECU, AFM, and injectors... apparently the stock injection runs to like 10:1 AFR when under boost or over 3800rpm. (So does the N/A ECU but it uses a smaller AFM/injectors)

 

so if i was to get a T2 ecu, afm, injectors and rip out the stock SE ecu and injectors... i wouldnt need a haltech f5 ecu?
if thats true.. that would be SWEET..

 

bump

 

On paper you could but I could never get the "factory set up" to work right on another car. I got sick of my car always running like crap and installed the E6K. It runs so much better now. So unless you want to try and succeed where others have failed; give it a try. Also with a E6K or E6X you can retard the timing under boost.

 

thanks paul.. also.. is there a way to retard the timing with the stock ECU or with the stock setup at all? The E6X/K are quite pricey, I'd much rather not spend that much money right now.

 

Not that I know of. The -SE ECU is fuel only. You could turn the dizzy to retard timing all the time. I think that some of the blow thourgh guys are doing this.

 

ok sounds good, thanks again paul. I think I am going to go with the haltech F5 ecu still because its not so expensive and you dont need an afm, and can run more injectors with it. Are SE injectors high impedance or low impedance?

 

Can you use the F5 as a standalone?

From the web....

The HALTECH F5 is a supplementary fuel injector computer designed to control the fuel delivery of an additional injector or injectors fitted to an engine’s fuel system as part of an after-market turbocharger or supercharger installation. Used as piggy back computer to trigger secondary injectors while still using stock ecu.

 

I wasnt going to use the F5 as standalone no. I was going to use it with the stock ECU unless i can run just a stock T2 ecu to do the same job. I think the haltech f5 and the gsl-se ecu in conjunction would be more tuneable as opposed to the t2 ecu.

I would still like to know if SE injectors are high or low impedance.

 

FYI I had my 85 se injectors cleaned and tested at RC engineering and they flowed 720 so it probably is true that 84 was 680 and 85 720

 

cool thanks..
I want to get 2 - 550cc T2 injectors and have mine tested and cleaned as well

 

gslse injectors are low impedance

 

thanks a TON .. im so pumped up now.. OH.. and are T2 550cc injectors ALSO low impedance? *crosses fingers*

 

86 to 87.5 they are low, 87.5-02 they are high

 

thanks again

 

I didn't re-read all of the post so I don't know if someone has answered this but I think you will need an aftermarket ecu, Microtech, haltech, or something. I have heard of people trying to put the gslse injectors into there t2 motors running the stock ecu and the car runs like crap because the ecu doesn't know those bigger injectors are in there. You will need something to tune them down.

 

agreed.. good point. I will go with the haltech F5.