Quick question for you SS/SC guys:


I've seen people say that the Stage 1 and Stage 2 reflashes are the same. I've also seen alot of people say that Stage 2 runs very rich so they throw on a 2.9 to lean it out. If those two things are true, wouldn't Stage 1 run extremely rich because of the larger pulley?

 

A 2.9 will lean out up in higher RPM ranges because it will start to max out the injector duty cycle ... meaning the injectors can no longer supply enough fuel to keep the AFR rich . If you had two cars with stage flashes ...1 with a stage 2 pulley and the other with a 2.9 , at 4000 rpm they both will be running the same AFR .

The Stage flashes are both the same , they have a set AFR . With stage 2 the only thing that changes is how hard the injectors work, for instance if the command Air Fuel Ratio for both kits is 11.0 , stage one will produce that with a 70% Injector Duty Cycle . Stage 2 will need more fuel to keep that 11.0 AFR because the smaller pulley is forcing more air into the motor , so the injector's will work at a 90% IDC to keep up. These numbers are a guess used as an example because i'm not sure what the real values are , but it should help explain. The AFR is a set parameter in the flash , the injectors will flow more or less to keep it a constant .

Where you live effects the AFR in the same way , if you live at sea level the injectors work harder to keep the commanded AFR than they would in Denver where the air is alot thinner . Going form sea level to 5000 ft is just like changing a pulley size . I hope this makes some sense, there are guys on this site that can explain it alot better than I .

 

Gotcha. Thanks, rukkee!

So its not necessarily the best idea to drop pulley sizes to lean out the stage 2 tune then? I know alot of guys do this and don't seem to have a problem, but it seems like a solution that could backfire on someone (maxing out injectors that is)

 

I went with Stage 1 and bought my own pulley from ZZP . I running a 2.9 with no problems but I have a lot of supporting mods so I don't have to worry about it going Boom

 

I have stage 2 with with a 2.8 & My AFR on 3 Dyno runs was 11.40 to 11.60 at its Highest!

 

Stage 2 must be really rich then!

 

In that case, are guys with Stage 2 having any problems with their cats clogging?

 

Yes , mine was replaced about 5K miles after stage 2 was installed .

 

Not yet.... been about i dunno 5k maybe less. Crossing the fingers though.

 

i had my cat clogg so bad i couldnt get past 10 mph! it was brutal, but it was o na custom tune.

2.8 + stage 2 is fine in MOST CLIMATES, but it depends on the car. literally.

as for stage 1, and a 2.9, it will NOT lean out the injectors... check flow charts, its just not possible.

 

could use any suggestions on this ... i'm lookin to put a smaller pulley on my 06 ss/sc but was wonderin how small of a size i can go with using 36# injectors and not leanin the car out...

thanks