Which injectors?
02-01-02, 06:24 PM
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Which injectors?
What type of injectors should I use in a 1987 N/A RX-7? I'm thinking of getting 550 primaries and 720 secondaries, fed by a Walbro fuel pump. What color or impendance (spelling?) should I ask/look for? I'm trying to buy used and wanna make sure I get the right parts..
02-01-02, 08:45 PM
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89+ cars have high impendence, 88- have low impendence. But, if you can only find some high impendence then you can wire up a resistor (do a search and you should come out with some results, im not sure as to how big of one you would need) and use the high impendence on a low impendence machine. i hope i have this right.. im tired as hell.
Good Luck
Good Luck
02-01-02, 08:55 PM
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According to your sig you only have bolt-on items for your car. No porting done to the engine, right? The stock N/A injectors will support up to 230HP at 80% duty cycle. I can't find the equation to show you but its on this website(www.sdsefi.com). I'm building a ported series4 engine for my FP car and I will use the factory injectors. I'm expecting about 200-210HP if all goes as planned.
IMO you will be wasting you money to put larger injectors on you car if you are still running a stock port engine. You would be better off having your injectors proessionally cleaned.
IMO you will be wasting you money to put larger injectors on you car if you are still running a stock port engine. You would be better off having your injectors proessionally cleaned.
02-01-02, 09:01 PM
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Originally posted by Roy James
89+ cars have high impendence, 88- have low impendence. But, if you can only find some high impendence then you can wire up a resistor (do a search and you should come out with some results, im not sure as to how big of one you would need) and use the high impendence on a low impendence machine. i hope i have this right.. im tired as hell.
Good Luck
89+ cars have high impendence, 88- have low impendence. But, if you can only find some high impendence then you can wire up a resistor (do a search and you should come out with some results, im not sure as to how big of one you would need) and use the high impendence on a low impendence machine. i hope i have this right.. im tired as hell.
Good Luck
Most likely, he needs low impedance injectors since it is an '87, but there is only one way to find out: put an Ohm meter to the existing injectors. He can also look for the resistor paks just below the air filter (I am pretty sure, but I have a S5 so I don't have these paks). Running even 550's on a N/A is alot of fuel. 4x 550 will provide around 260 hp. Can his n/a motor make that much power (I have yet to see a N/A RX-7 car make that much power in my life)? 720's are way too much, unless he is doing massive mods to the engine.
Jay
Last edited by Boosting_FC; 02-01-02 at 09:05 PM.
02-01-02, 09:48 PM
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No.. that comes later... For now, just a turbo.. I knew if I mentioned it no one would take me seriously... Since its fine to run a Supercharger at 8psi, but as soon as you slap on an intercooled turbo running 8-10psi, my car will blow up imeadiately and I'm a dumbass for trying to make what I have faster... I plan to use such large injectors for the "aftermath"... When I blow my engine eventually and build it up as a costom, high compression turbo motor.. Anyway.. Thanks for the answers.. Time to start shopping 
Originally posted by Cap'nWankel
planning on porting the motor?
planning on porting the motor?
Last edited by Drakk0r; 02-01-02 at 09:55 PM.
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02-01-02, 09:57 PM
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You most likely need the low impedence injectors. You can ohm your secondary injectors real easy. They should be 2-3 ohms. If they're 12 ohm thats high impedence. Easier still is the solenoid resistor pack located about six inches under your air filter, mounted on the frame. Its bright silve in color, about six inches long and two inches wide. One large plug. You can see it if you stand in front of the car, and peer thru the crack b/t the front of the air filter and frame. You WILL see it. Its in line with the boost/pressure sensor. Money says its there which means you have low impedence.
EDIT: Read this thread https://www.rx7club.com/forum/showth...threadid=48718 and the first guy has the cutoff date for the low impedence injectors, RotaryRX7......I believe was the writer. You need to know your vin number is all to figure it out.
EDIT: Read this thread https://www.rx7club.com/forum/showth...threadid=48718 and the first guy has the cutoff date for the low impedence injectors, RotaryRX7......I believe was the writer. You need to know your vin number is all to figure it out.
Last edited by HAILERS; 02-01-02 at 10:05 PM.
02-01-02, 10:16 PM
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DOH!
I KNEW I HAD IT BACKWARDS TOO!! haha, i checked mine today to make sure everything was ok and i have an 88 DDOOHHH!! my dislecsec (sp?) *** has struck again, haha. Thanks for the correction.
Originally posted by Boosting_FC
You got it backwards. If your car requires high impedance injectors, you can wire up resistors (~10 Ohm) to a low impedance injector, not the other way around. Most 88 (and some late 87) cars use high impedance.
Most likely, he needs low impedance injectors since it is an '87, but there is only one way to find out: put an Ohm meter to the existing injectors. He can also look for the resistor paks just below the air filter (I am pretty sure, but I have a S5 so I don't have these paks). Running even 550's on a N/A is alot of fuel. 4x 550 will provide around 260 hp. Can his n/a motor make that much power (I have yet to see a N/A RX-7 car make that much power in my life)? 720's are way too much, unless he is doing massive mods to the engine.
Jay
You got it backwards. If your car requires high impedance injectors, you can wire up resistors (~10 Ohm) to a low impedance injector, not the other way around. Most 88 (and some late 87) cars use high impedance.
Most likely, he needs low impedance injectors since it is an '87, but there is only one way to find out: put an Ohm meter to the existing injectors. He can also look for the resistor paks just below the air filter (I am pretty sure, but I have a S5 so I don't have these paks). Running even 550's on a N/A is alot of fuel. 4x 550 will provide around 260 hp. Can his n/a motor make that much power (I have yet to see a N/A RX-7 car make that much power in my life)? 720's are way too much, unless he is doing massive mods to the engine.
Jay
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