what size injectors do i need

[lnewton1974]

i am trying to finish my car before spring and my problem is im not sure which size injectors i should use. i have a 20g turbo and a walbro 255 fuel pump. i was told that i can use 550's but i have heard that those might be to small so if anybody can help me i would buy for ever indebted to whomwver so iv advance thanks for the help

 

[Zdrummer15]

More info would help, but you won't be maxing out a 20g with 550's, I can tell you that much.

 

[Dsmj89]

If you go to extremepsi's website, look at the price for fic 550 injectors, it is the same price all the way up to 850cc, i would just suggest you go for the 850cc since it will cost the same, that, AND 550cc is pretty much pushing the limit on it with a 20g.
850cc injectors will deffinately work with your 20g nicely and still give you headroom to improve if you ever decide to run slightly more boost or a slightly bigger turbo.

What will you be using to tune ?

 

[lnewton1974]

i am using an apexi neo to tune with, a buddy of mine told me that this was the best and easiest thing to tune with, i already have a front mount installed and plan on a new fuel fuel rail and afpr i have installed already a wide band gauge and boost controler but as far as any other engine mods nothing yet just trying to figure out the injector problem first then work my way to finishing everything else so thanks again for the help

 

[RadDsm]

a buddy of mine told me that this was the best and easiest thing to tune with

Don't get anything bigger than 650cc with the SAFC

 

[Zdrummer15]

Yeah you can't really control much more then 650's with an AFC. Look into ECMLink. That will allow you to run as big of injectors as you want. Also, you won't need a new fuel rail. The stock one is fine for any goals you likely have.

 

[chinola69]

Why shouldnt he go bigger then 650 with the AFC

 

[lnewton1974]

i am new to tuning and building on imports so why cant i go bigger than 650's with tuning with the neo

 

[Zdrummer15]

It just isn't capable of compensating for injectors that big. You can do a search on it if you want more of an explanation. If you want to max out a 20g you are going to need bigger injectors then that. Besides, you can get much bigger ones for the same price as 550's so it gives you room to grow at the very least. It's still impossible to recommend an injector size without knowing how much boost you plan to run (and that's only if you get something better to tune with). Even then, the only way to truly know if your injectors are big enough is to log the car and find out. My suggestion would be to look into ECMLink V3 or V3 Lite. Then buy bigger injectors in the range of 850's or more. ECMLink will take care of your tuning and logging needs and you can run as big of injectors as you want.

 

[RadDsm]

The SAFC tricks the ECU into seeing less airflow to compensate for the larger injectors. The ECU has maps created for more timing when there is less airflow (like for cruising conditions). Since the SAFC can't control timing, you can see a lot of timing advance, causing knock/detonation.

 

[akira235]

definately get ecmlink. for any turbo other than a 14b its pretty much essential. you can sell your afc neo for 200ish, and v3lite is only 375+socket service/conversion (depending on whether you have an eprom ecu) or, you can try to find ecmlink v2 for a little bit cheaper used.

 

[MY1GDSM]

More info would help, but you won't be maxing out a 20g with 550's, I can tell you that much.

ok... I tuned a friends car awhile back an maxed out 680's with a 20g on low-mid 20ish psi...



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[forzarallyOZ]

I am running a 255 with 550's in order to keep good gas mileage but making good power. Just to give you an idea. To max out, I'd would probably get bigger ones.

 

[M5talon]

680 cc should work with afc, if not just buy DSM-link and get some 880s and you will be making some good power

 

[Cam_Ron]

+1 for making sure that you can reduce ignition advance with a larger turbo. Generally speaking the amount of peak timing that oem manufacturers use is very aggressive for anything other than a turbo that is of similar size/airflow to the stock unit.