mhi big16g @ 18 psi, will i max out my 550's?

[gsx ftw]

i can step it up to 650's, but i heard an safc or afc neo wont' be able to control them at higher IDC's. any truth to this?

i've picked up an safcII for dirt cheap, and i'm going to put off dsmlink for now.

oh, i have a 190lph walbro and fuelab fpr as other supporting fuel mods.

 

[CanadianTSi]

You will be ok with the 650's/s-afc combo...I ran the time in my Sig with that combo.

 

[ApexVIII]

evo's run 560cc stock any mine stock boosted 20psi , so you will be fine.

but i woiuld go with 650's though

 

[JayRolla]

I ran out of injector at 16psi on my 550's, not sure why but I did. I would go with 650's also.

 

[matthewdesigns]

I ran out of injector at 19psi on 550's/Evo316g, so you'd be close to the edge. Go with the 650's for a little extra margin of safety.

 

[daren_p]

I ran out of injector at 16psi on my 550's, not sure why but I did. I would go with 650's also.

Could have been because of the lower base fuel pressure in the 1g's. They run ~37psi stock, while the injectors flow rating is usually measured at the industry standard of 43.5psi. 2g's run the typical 43.5 base fuel pressure from factory. You may also have had a richer air/fuel ratio compared to others.

On a 16g @ 18psi with 550's you may not max them out but you'll be getting close & more then likely over the recommend, keeping your IDC under 80% level. On my buddies 2g, with a base FP of 43.5psi, he was seeing 98-100% IDC at 20psi on his 550's with an evoIII & stock cams. His air/fuel ratio was right around the 11 to 1 range IIRC. I too would defently recommend the 650's.

 

[gsx ftw]

I'll go for the 650's then. Thanks guys.

 

[pj91gsx]

510s are good up to 18 psi and 550s are good up to 20 psi

 

[gsx ftw]

i would go 650 in a heartbeat if i hadn't heard that an safcII or afc neo can't handle them at higher IDC's

i'm pretty sure i'll be going for the 650's though