I'm planning on installing the 3.12 pulley. I currently have the complete vortech system w/ fmu and inline fuel pump. Would there be any benefit (i.e. safer?) of adding bigger injectors, like 380's, 440's, or 500's? Would I be able to run a lower and safer fuel pressure through the bigger injectors?

I know that many ppl are safely running the 3.12 with stock injectors BTW, but I would just like to add an extra margin of saftey if possible.

 

You can probably do a search and find the formula that allows to compute the capability of OEM injectors Vs your current Vortech SC rwhp. I know I have seen it posted on this site. Perhaps someone will jump in a provide the formula.

I did the calculation and determined I was close to being maxed out. So, when I installed the Kinetix SSV I installed PE380s. I also sent my ECU back to TS inorder to have my ECU reflect change in injector size.

 

i have some lightly used pe 380's for sale

 

SungNam...did you have to change the washer in the FMU , so you dont build as much fuel preasure in the rails ? Or did you just have to reduce the numbers in the fuel map ?

 

Bill...Went back to stock washer in the FMU and then after having TS do their ECU thing for 380s, did everything withing the SS fuel map using R4 program. Took a while but the A/F line is GREAT!

 

RC440's would work fine with around 400whp on a vortech right?

 

I have 3.12 pulley with stock injectors and I/m running lean after about 6k rpm. I will be doing RC550's soon...

 

Aron..do you know what your fuel preasure is up top ? Gauge ?

 

Hmmm.... im running the same setup and never get above 11.2 after 6k.

 

For a truely safe and proper setup, you may want to consider removing the FMU, and split second box, and running larger 440cc injectors, a return fuel system, and an eManage Ultimate for tuning. Although its a more expensive solution, it is the technically correct setup. 120psi of fuel pressure is flat out scary at WOT with that FMU.

 

I have my 3.12 pulley on order and hoped to have it in with a dyno/tune this week. The pulley hasn't shown up yet, so I guess I'll have to wait 'til next week.

I'm hoping to get by with stock injectors on the 3.12 for a few months before I do my winter mods. I have him tune it for the stock injectors and back off if necesary so I don't go to lean.

In about a week I hope to post my before and after dyno with boost and a/f plotted. Can you also post a before and after dyno?

My winter mods will be experimenting with a 2.87 pulley and wastegate/boost controller. I have the RC440's injectors and Walbro 225 fuel pump, but am waiting for some extra $$$ to get the full fuel return system.

Please post how you 3.12 swap goes...

 

RC Engineering has a nice little calculator and formulas to help chose the right size injectors. You could also use this to estimate the duty cycle given you know (or estimate) the other parameters.

Link

For my vortech I was estimating

Crankshaft Horsepower = 450 (dynoed and tuned to 400hp)
# of injectors = 6
BSFC = 0.6 (worst case for supercharger?)
Fuel pressure = 130 psi (max for 2.87 pulley?)

It seems like a RC440 would have a duty cycle or 0.62.

 

Thats why I asked what his fuel preasure is at . If it is not increasing 8psi per LB. of boost . He could get lean . He also can increase the numbers in the fuel map up to 20 if need be . He also may have had AAM flash his ECU to run the fuel and timing . And several guys have PMed me saying that AAM flashed for fuel and timing and couldnt get the A/F rich enough to be safe up top .

 

I know i said i had the same setup as aron, but i do not have the aam reflash, just the 3.12 pulley on stock injectors and dual exhaust.

 

I did have the AAM reflash but they told me I'm just running out of fuel up top. But, I also have cams as well and a very open header / exhaust / test pipe setup. I have taken it way past 6.5k rpm and have had no problems. BUT, my dyno sheet does show a spike after 6k rpm. I'll post my dyno sheet when all said and done after install of Kinetix SSV, 550 injectors, 2.87 pulley, and reflash and retune. Hoping for 430rwhp or maybe more. I dont think thats asking for too much...

Aaron

 

Although my stock internals may think otherwise.....haha

 

The number you see most around these threads is a max of 350 mid-range TQ before the rods give... push that and a winter build up is just around the corner...

 

yeah, and my car has 75k miles too....I better save for these internals before I lose the motor.

 

Aron...do you still have the SS box and the FMU hooked up ? If so take it some place else that knows the SS box and have them add some fuel up top .That running out of fuel line seems to be AAM's M.O. . Ive had 4 or 5 guy PM me saying the same exact thing when they flashed for the Vortech and the 3.12 pulley . They are the only ones having problems getting enough fuel up top . Why do you think that is ????????

 

Don't they sell a $995+ fuel return system that will keep that from hapening?

I'll post what my tuner is able to do next week with with SS box and 3.12 pulley.