After reading the thread most people here don't know how to use Uprev and how are AFR's work,the correction factor is between 75%-125% with 100% being on the money if the ECU moves the AFR toward the 75% it is taking away fuel and toward 125% it is adding so the reason for tuning is to get the car to run as close to 100% as possible so the ECU has full range to adjust rich or lean depending on the information it receives from all the sensors.

If the ECU is not adjusted properly let say it at a giving RPM and load it is running 125% it is maxed out and can not add anymore fuel this is why it is VERY IMPORTANT to get it to 100% so it can do it job.

You guys get the point.:tiphat:

i understand what you're saying and it makes sense. funny thing is you say maxed out A.k.a. running lean. My car with all my bolt ons was running so pig rich at points hitting 10.9:1 in the afrs. my car was straight up dumping fuel without a tune. my mpg was like 17-18 without the tune. got it leaned out to 13:1 afrs and my mpg is back up to low 20's and the pulls like a beast. Maybe my car is an oddball but without the tune i was running stupid rich and needed to lean it out bad!

I swear I just got a case of deja vu. I'm not sure which post of culmination of posts brought you to the conclusion. But the intake runners are longer and the manifold is wider (except throttle body positioning). It's going to effectively move your peak power, hence the slight loss most experience up top. I still said he needs a tune afterwards to get the most benefits, but also, running the manifold isn't going to make his car go dangerously lean. I would say most of us know not to tune a car on the edge, or have a tuner push the envelope too far for a few more hp. At 2000ft, I was just over 13 AFR with out tuning. Until my Pre cat O2 sensor crapped, then it just ran rich.

Every tune from Nissan is the same but not every engine is the same,the fuel comp table in Uprev has a 16x16 grid,which has 256 differant cells to adjust the A/F, some cells maybe rich some good some lean yours must have had more rich.
But these cars are usually really lean down low and get really rich as the RPM's go up.

OP, put it on and get a tune...then enjoy the results!

super odd... glad its runnin good now!

The way I see it, there is a big resale market for these if it doesn't work out for you. When I tuned with the manifold, that was at 304whp and 243lbft/tq. When I installed my stock manifold and came back a week later, baseline was 302whp and 232lbft/tq. After tuning, I gained 4 more whp and tq. The gain was only after 7200 rpm. See below for final results and why I bought it again brand new. I plan on keeping it on with the superchargers too.

http://www.the370z.com/members/ss_fi...s-m370-din.jpg

that midrange gain is impressive!

Absolutely necessary?

If the ECU has to run excessively high fuel trims to maintain target AFR's (resulting in a CEL), there is knock under load, or driveability is poor.

What mods could cause this condition? Any major change to the intake or exhaust plumbing orientation, diameter, or flow.

Individual results may vary...

Im going to pop it on, and just drive her easy until the tune in march...

The engine will go into a 'mode' where it dumps fuel in open loop mode, if you add too many breathing mods without a tune.

The Nismo intakes (that I have) are one mod that if you put it on without a tune, it'll just go full rich, 10.5:1 or whatever the low threshold is on our O2 sensors. Even with their MAF spacers (which are just like the ones AAM includes in their intakes).

Strange, but I think it's a protection mechanism.

Good to know, didn't know that.

I am going to keep this very simple (I have made other posts about this subject and I don't feel like re-writing everything again):

If your mod is anywhere between the MAF and the 02 sensors, you very likely need a tune.

Good short and simple way of putting it!

sorry wrong post!