Bigger injectors on 7MGE

[EwGoetsch]

Just got my cylinder head back from the shop, and im going to be putting together my motor tomarrow. I was going to turbo it and bought all the parts but things changed, i need a more reliable car for the winter to come and i think keeping it NA for a few months wont hurt. I still got my stock 7mge injectors but they look really bad,(180,000 mile engine). I bought some 7mgte 440's but i did some searching and found it wouldnt work right. I do have a lexus afm, and 7mgte fuel injector resistor. Would i need to run on 7mgte electronics? or could i use the bigger injectors with the Lexus afm on GE electronics?

 

[935motorsports]

Are your original injectors green or yellow?

 

[EwGoetsch]

Are your original injectors green or yellow?

greeeeen

 

[gofastgeorge]

The only way to use the OEM turbo injectors, would be to use them with the complete 7MGTE ECU, harness, and all the GTE sensors.

Save yourself some head ackes for now, take your stock injectors into an injector service, and have them cleaned.
Put them in, and run it.

 

[CRE]

Can't use the Lex AFM on the GE electronics anyway.... besides, the stock injectors flow more than you'll ever need for a N/A 7M. The only thing you're really going to accomplish would be running even richer at WOT and while warming up from a cold start... the 7M's are tuned rich enough as it is. But, if you want to richen things up add a fuel controller instead of blindly just throwing 25% more fuel at the engine.

I'm with George, get them serviced, have them flow tested and put together a set of matched injectors... you'll probably have to send in a couple extra injectors to put together a matched set.

There are other reasons not to use larger injectors than you need for a build... it's called resolution. You can get a tighter tune if you run injectors with a smaller scale as each percent is equal to a smaller quantity of fuel and thus you can tune to stay near a chosen AFR much more aggressively... (for example) pulling 1% would pull 5cc on a smaller injector where pulling 1% on a larger injector may pull 10cc... you've just lost your ability to fine tune.



EDIT: I just saw that you're planning on turboing it in the future. Still, for now I'd get the injectors serviced and put together a matched set... and in the meantime collect the GTE electronics and put together a matched set of GTE injectors.

 

[amichie]

Can't use the Lex AFM on the GE electronics anyway.... besides, the stock injectors flow more than you'll ever need for a N/A 7M. The only thing you're really going to accomplish would be running even richer at WOT and while warming up from a cold start... the 7M's are tuned rich enough as it is. But, if you want to richen things up add a fuel controller instead of blindly just throwing 25% more fuel at the engine.

I'm with George, get them serviced, have them flow tested and put together a set of matched injectors... you'll probably have to send in a couple extra injectors to put together a matched set.

There are other reasons not to use larger injectors than you need for a build... it's called resolution. You can get a tighter tune if you run injectors with a smaller scale as each percent is equal to a smaller quantity of fuel and thus you can tune to stay near a chosen AFR much more aggressively... (for example) pulling 1% would pull 5cc on a smaller injector where pulling 1% on a larger injector may pull 10cc... you've just lost your ability to fine tune.



EDIT: I just saw that you're planning on turboing it in the future. Still, for now I'd get the injectors serviced and put together a matched set... and in the meantime collect the GTE electronics and put together a matched set of GTE injectors.

I agree with this post entirely. I have tried both the factory 315cc injectors and the 1uz 251 cc injectors and both worked well. I think each 315cc injectors is rated at about 50hp. SO to get 300 hp out of NA 7M is a challenge.

 

[935motorsports]

Yes, since you are green injector (high impedance), you can't just throw in the turbo injectors (low impedance).

Your harness has no spot for the resistor pack, so wiring one in would be a challenge.

However, if you are going to go turbo anyway, you can convert to full turbo electronics. I was using it on my 7mge for a short time. It ran fine but was just a bit soggy due to being really rich in the upper end. If you had an SAFC you could compensate.

 

[EwGoetsch]

Thanks for all the great info. I pretty much have the whole gte electronics setup besides an ecu. Ive never had injectors cleaned, anyone estimate a cost for me?

 

[CRE]

I had several injectors serviced and flow tested so I could put together a matched set... ran me about $20ea. I'll look for the invoice, I can't remember where I had them done; There are a few places though which members on here recommend. If you look at how much variance Toyota specs allow in the injectors you'll understand how a matched set could make a MASSIVE difference in both performance and engine longevity.

If you'll be going turbo soon I'd get a set of GTE injectors serviced and just wait. If you're going to be installing a fuel controller you could install that and the injectors while still running the GE electronics in the meantime.

 

[taka21]

not to threadjack but if you have yellow injectors does that mean you can just swap the gte ones in and be fine?

 

[sas'd7mge]

im with taka21...i have a set of yellow and a set of green injectors (both high impedance, correct?) and want the have them sent out to witchhunter.com to have them cleaned before i put them in my rebuilt n/a (and staying that way) the yellow are 295cc and the greens are 315cc. your thoughts?
the motor is going into my toyota pick-up :biglaugh:

 

[CRE]

No, yellow topped injectors are low impedance and green are high.

GTE injectors can be used in pre89 N/A's and vice-versa.

As for the flow rates, don't go by any number you've just seen posted up on the net. Toyota says the green may flow anywhere from 276cc/min up to 340cc/min and be within spec (the specs for the yellow state 260cc/min up to 320cc/min)... never have found anyone who can post an actual published rate. With the amount of variance that Toyota says is fine and the fact that the injectors are ~20yo you're best off sending in 8 to 10 of the same model (yellow or green) and have them flow tested when serviced... build a nice matched set from there and you'll know what they're flowing for sure... be sure to ask what fuel pressure is used when they flow test them and remember that that pressure may not be the same as your car's and as such you will most likely still flow more or less than they're capable of.

 

[taka21]

No, yellow topped injectors are low impedance and green are high.

GTE injectors can be used in pre89 N/A's and vice-versa.

As for the flow rates, don't go by any number you've just seen posted up on the net. Toyota says the green may flow anywhere from 276cc/min up to 340cc/min and be within spec (the specs for the yellow state 260cc/min up to 320cc/min)... never have found anyone who can post an actual published rate. With the amount of variance that Toyota says is fine and the fact that the injectors are ~20yo you're best off sending in 8 to 10 of the same model (yellow or green) and have them flow tested when serviced... build a nice matched set from there and you'll know what they're flowing for sure... be sure to ask what fuel pressure is used when they flow test them and remember that that pressure may not be the same as your car's and as such you will most likely still flow more or less than they're capable of.

ok cool, cause im planing on doing a junkyard turbo setup running the stock ct manifold and downpipe on ge electronics so i was wondering that too
thanks for clearing that up