Anyone know if I'll be running dangerously lean with this combo?

Saved some cash and planning to buy/install all of these at once... I'm clueless when it comes to AF ratios... so if anyone has any experience with this, that'd be great

If i really am (will be) running lean, what can I do/buy to fix it?

 

Hi-flow Cats cause a lean condition at mid RPM range per Technosquare. Per Jason at Performance Nissan lean at mid range will not cause damage, lean at high RPM is deadly. Technosquare checked a spark plug prior to re-flash of my ECU and plug was white or "colorless" (lean). After re-flash and WOT run, plug was light tan. Do all your mods and have your ECU re-flashed to raise your RPM limit to 7100 RPM, raise youy speed limiter from 156 MPH to 200 MPH and adjust your A/F mixture to 12.5 all the way to redline.

 

You will run very lean with that setup; I know because I had the same setup before. There are several options you have to tune the A/F. You can either send your ECU to technosquare for a reflash, you can get an apexi s-afc2 and go to a dyno w/ o2 gauge to tune, or buy an s-afc2 and wideband o2 sensor and learn to tune it yourself. I decided it was too much money to spend on all that crap for the gains it would have given me, so I sold all my engine mods (JWT, plenum, y-pipe, etc). Now I got enough for either rims, a beater car, or an sr20 to build on...

 

so what I'm hearing is, I'm better off not installing all of these mods unless I'm ready to commit to another 500-700 dollars in AF tuning... but suppose I just went with:

1) a popcharger and cats, or
2) a popcharger and y-pipe

... would I still be running dangerously lean?

I guess my question is that out of those mods, which ones or combination thereof will give me the most gains without needing an AF tweak?

 

You are correct about your 500-700 assumption.

With the two options you have listed, #1 will give a greater gain.

I would HIGHLY recommend you get rid of all of those mods and pocket the $1500 or so and put it towards F/I or lightweight wheels/tires (which will make accel/braking/handling better). I've been through a laundry list of N/A mods on this car and my final decision is that while they are nice, they simply don't return the HP/$ to make it worthwhile.

That said, I have hotchkis sways and will be getting springs and koni shocks, and eventually a vortech. Once again, best of luck with whatever you decide!

 

You'll be fine... I've been running that setup for 20k miles.

Quit letting people worry you.

 

wren57: thanks man... good advice... this thread has definitely changed my mind about throwing so much money at N/A mods... but I've already ordred my popcharger so I guess I'll stick with that for now ...

PhoenixINX: thanks for your input... what combo cats/intake are you running? have you performed a dyno to check your AF?

 

same thing here..about 20000 miles with rt cats, nismo exhaust, and pop charger. No problems at all. Once the APS plenum comes out I'll get the reflash done.

 

I have been running my setup for a while with no problems. Easy way to check if you're lean.....your tailpipes. Clean them off and if they get black on the bottoms again, then you know you're not running lean.

 

Test pipes+plenum+headers and still having black tips

 

so, black tail pipes as opposed to... clean tail pipes? sorry air/fuel ratio is foreign to me.

 

Black tailpipes means you're running rich (lower a/f). If the tail pipes are relatively clean after you wipe them and have been driving around for a while, then you're likely running a little lean (higher a/f). I think my Z is running lean, as my tail pipe is quite clean . It's a very crude way of determining the a/f condition of your car.

 

Would I be running lean with a JWT and a Crawford Plenum, with resonated test pipes? Or would I be better off with just the JWT and the test pipes?