550cc injector problems!!!

[seamus7]

hey guys, i wanna make sure what i was told was true. I was running great up until i replaced my 440's with 550's just today. idles fine but when i open it up it bogs and bucks a little. it also sounds alot different. almost like the turbo is wide open. but that might be another issue. what i heard was i need a FPR. i have a warlbro 255 and a safcii but thats it. my other mods are:

Stock block and head (7 blot 4G63T)
Tubular headers
Big 16g
Tial External wastegate
Custom Dump tube
3" Turbo back exhaust
Blitz Blow off valve
Hks Dual Stage boost controller
Hks turbo timer
SAFCII
Auto meter Boost gauge
Act 2600 lb. clutch
fidanza lightweight flywheel
rebuilt tranny
running at 19psi

Like i said it was running top shape till i played with it today. I have to hook up the front mount tuesday. after that, then what? Cause i need my car to run like it did before. help guys!!!!!

 

[bluegs03]

dont mean to be obvious but did you tune the new injectors into the safc2

 

[seamus7]

no i didn't but should i wait til i do the front mount to retune it? the front mount is going to be piped in on tuesday.????

 

[LTUDSM]

well put back 440cc's,After you done with your Intercooler.Grab your 550cc injectors,call Ivey Tune for an apointment and go to do a dynotune or just Search on the board,you will come up with a lot of base settings 550cc vs afcII

 

[kenamond]

And you probably still want an AFPR, too. You'll overrun the stock FPR with a 255 FP which makes you run rich at low rpm.

 

[KelTsi90]

Get the fpr and lower the Fuel Pressure a little.

 

[oVaBoost]

You will need to tune the car with AFC or some kind of tuning software its posted in many other threads

 

[seamus7]

thanks guys. i wanna do this right not just half ass it. thanks again

 

[spyderturbo007]

Do you have a logger? If so, we can walk you through the tuning process. If not, you really need to get one before you start messing with larger injectors. If you can't afford one right now, put your stock injectors back in until you have some extra cash.

 

[codyw]

Theres no point in waiting till after the fmic is installed. its not going to make a difference. The cars got to be tuned regardless if bigger injectors are put in. If your going to be modding the car steadily over the next few years I'd highly recommend getting a wideband. then you can tune it yourself accurately and not pay the expensive dyno charges.

 

[99 gst spyder]

mine was just exactly like that too after i put in my 560cc in... after that i took it for a dyno/tune with the 560cc in, it ran much better just like before the inj were in...you should get fpr and get it tune.