550cc with safc?..need solid advice

[uncle_louie83]

ok...i know i have brought this up before but i cant get solid advice....i found a place that will sell 550cc sidefeed injectors for a decent price....question is will the safc be able to make these idle somewhat ok. The thing is i know the safc can control 520cc injectors easy with decent idle. But this is 30cc over stock...some ppl say oh its only a small amount...30cc isnt going to cause a problem but others say it will...i believe it will make a crappy idle. but i was wanting some solid evidence here. I dont wanna buy them now but sometime i do. so if anyone can chime in let me know.

lewis

[KATwo40]

Where did you get 30cc? Stock injectors are 270...550 is far more than 30cc over 270.

[LEMHEAD16]

He is trying to say AFC will control 520cc injectors. 550 is 30cc larger than that.

[BillKlineVT]

mine idles just fine... 550s with safc2... no biggie

[:: orion ::]

Despite what the sticky topic may say...stock KA injectors are 270cc.

S-AFC can do double the stock setup, so 270x2 = 540. 10cc difference...and really, an AFC is NOT a precise enough device for 10cc to make any difference.

...

But FYI...DO NOT try to extract the HP potential of these injectors on a stock ECU without some timign control. You may know this, and I assume you do...but for the newbs...fuel is only HALF of tuning.

- Brian

[BillKlineVT]

Despite what the sticky topic may say...stock KA injectors are 270cc.

S-AFC can do double the stock setup, so 270x2 = 540. 10cc difference...and really, an AFC is NOT a precise enough device for 10cc to make any difference.

...

But FYI...DO NOT try to extract the HP potential of these injectors on a stock ECU without some timign control. You may know this, and I assume you do...but for the newbs...fuel is only HALF of tuning.

- Brian

I second that... attempting to use 550's to their full potential without timing control is a disaster waiting to happen. Hence the reason why I'm selling my safc so that I can actually use these 550s for what I got them for... to satisfy my GT turbo's desire for higher boost.

[uncle_louie83]

yes i know about the timing control part...so where did you get 270cc? because everywhere i look they all say 260cc...if they are 270 then that makes life a lil easier but i need some rock solid evidence here....where can you tell me to find if they are 270cc injectors?

lewis

[BillKlineVT]

they're 270s... why do you need to know "rock solid evidence"...? If it works, it works

[uncle_louie83]

your prolly right...im goin to go look at the extra injectors i have at work tomarrow...the code on the side should let me know...if not then ill call nissan!

lewis

reason why i like to know is because i like details. Im always thinking of a new way to do things or get things done. and if i know for a fact that there 270's and not 260's then i can help my friend aaron with his 555 injectors.

[Craving4Boost]

you dont really need solid advice because there is solid evidence on this forum that people use 550cc's with a SAFC and have no problems..just ask them

[bruinbear714]

550cc will work with any piggyback, but be aware that your timing will be adversely affected, especially if you're going from 270cc to 550cc.

[Structure240sx]

i also ran 550's on a stock ecu with safc for months, idled perfect

[toki]

if you are running enough boost though shouldn't you be able to "0 out" or get close to it on your afc in the high range though? Thus not affecting timing so much. Plus there is that highly debated EGR removed safe mode that is mysteriously retarded timing on some DEs.

[:: orion ::]

We're not worried about the S-AFC correction throwing the timing map off...that's a whole separate concern.

I'm talking STRICTLY about trying to make +250rwhp on a stock ECU, where it gives almost 10 degrees advance under full load and high RPM.

For example, for ~300rwhp, you'd need about 12-13psi from a decent turbo, and *maybe* 19-20 degrees total timing at WOT.

With a stock ECU, you'd be getting AT LEAST 28 degrees total, and a you'll detonate for sure. Goodbye KA.

...then factor in the S-AF correction and how it puts the timing curve in the wrong place (cutting the airflow voltage that the ECU sees will mean it senses MUCH less load, and give WAY too much advance = boom).

- Brian

[Structure240sx]

if you are running enough boost though shouldn't you be able to "0 out" or get close to it on your afc in the high range though? Thus not affecting timing so much. Plus there is that highly debated EGR removed safe mode that is mysteriously retarded timing on some DEs.

no, fuel pressure increases with boost. also to possibly zero it out the injectors would have to be running at complete max. i was leaning out my safc in high boost 19-20psi with 550's to negative (-)33-41% from 4k-7krpms to have the afr's in the high 11's and low 12's with race gas

[Florida240sx]

I'm putting on tomei's 555cc this weekend.If everything goes smooth. I have read in numerous places that it is 260cc injectors...

[Turb0wned]

ka injectors ARE 270cc

[sunnys14]

ka stock is 270cc!!!

[S14tat]

tomei injectors are very similar to nismo injectors. if they're as close as they say they are, then tomei injectors are 615cc not 555cc.

[fiznat]

Despite what the sticky topic may say...stock KA injectors are 270cc.

Huh just noticed that. Fixed!