AadosX

iTrader: (10)

So far I have a TurboXS y-pipe cat-back exhaust and Injen Longtube intakes on my 2007 350Z HR. Here is a dyno showing the A/F ratios, but they are only taken with a sniffer and I've heard they aren't very accurate. But as you can see, according to the sniffer, the intakes have leaned my car out some. The blue line is only the exhaust, the red line is exhaust and intakes.

I would like to install test pipes but I'm afraid that it will lean it out more than I'd like, and right now I can't afford a tune. I really don't want it any leaner than it already is. Do you think I should definitely wait until I can afford a tune? Also, is UpRev Cipher an accurate way to check my A/F ratios to see how they are, or is a true wide-band such as Innovate the only proper way?

I was always under the impression that a car's ECU was intended to measure the air and supply the correct amount of fuel.. I thought that was the whole point of the MAF so this is all kind of weird to me. I don't get why such simple mods are messing with my A/F ratios so much.. grr.

Thanks,
John

SparkleCityHop

iTrader: (30)

Your car has wideband O2 sensors, so you could use Cipher to see & log the AFR accurately.

MAF measures Air Flow
Wideband O2 measures Air Fuel Ratio

2004Black350z

iTrader: (37)

i drove lean for almost a year. Def not a smart move but it can b done. Depending on your local uprev tuner if thats what your gonna use but CIN gives u 2 adjustments in your tune. Which means u could go ahead and tune now add test pipes and have your AF fixed after if needed

hellsoldiers08

iTrader: (3)

but if adding test pipes that is suppose to make it richer correct? because when i had test pipes and back and added intakes it leaned me out some...

Junkster

iTrader: (3)

I am kind of in the same boat.

I have Stillen Headers, Stillen HFC's, Invidia Gemini catback, and JWT pop chargers on my HR. I figured if there is a CEL that comes on for "lean conditions" that it would have popped up if there was a problem with my AFR, i have yet to get a code like that...

I would assume the biggest negative is loss of power more than anything. Of course i wouldnt probably beat the living day lights out of the car untill you get a tune (like a full track day or something).

I may be completely wrong, which in that case someone chime in

AadosX

iTrader: (10)

Thanks for the replies so far.

My friend has Ciper so I am going to give that a shot before I install the test pipes to see if it works. I just wanted to be sure that it was going to get an accurate reading.. according to SparkleCityHop it should.. cool.

I'd love to hear some more input though, keep it coming!

stock07g35s

iTrader: (1)

When you are full throttle you are in closed loop. Closed loop gets fuel values from a table in your ecu. I you are making more power, or putting more air through the motor using the same values on the table to calculate injector pulse times, you will lean out a little. The MAF measures to keep the mixture correct when you are in open loop during normal driving to keep emisions low. Correct me if I am wrong for nissan. I came from Kpro.

Junkster

iTrader: (3)

I came from the streets yo...

holla

AadosX

iTrader: (10)

Ahh interesting. I wonder if that's in fact how our cars work?

Also, I just found out something interesting. According to UpRev's website, Cipher isn't supported with the HR 350Z's. Hmmm... I'm trying to get them on the phone to see what's up with that.

hotshot350

iTrader: (3)

cipher is supported for us. i have a full exhaust and got the uprev osirus about a few weeks before i put my z away for the winter. Im going to put the z back on the road soon and mess with cipher. I would deff get the tune though. it made my z run alot smoother and deff gained a few hp n trq.

Frostydc4

iTrader: (3)

I have cipher working on my HR 350z

AadosX

iTrader: (10)

Well I'm not saying Cipher doesn't work on HR's, but according to their website:

That being said, tonight my buddy hooked his Cipher up to my car for me (big thanks to Rob aka rh_334!) and it seemed to work fine other than possibly reading both mafs.

I am glad you guys seem to think that Cipher works on our cars..

So here's the deal, according to Cipher I am actually running very rich. I did a few WOT runs and under full throttle my A/F ratios never went above 12. In fact they were low 11's, approaching 12 as I neared redline, getting up to about 11.8. Cruising was at a nice 14.5.

I thought that exhaust and intakes would lean me out.. not the opposite?

SparkleCityHop

iTrader: (30)

Sounds like a tune is in order.

The experienced VQ tuners on here will probably know what numbers are best for our engines. But according to the book I'm reading right now "Engine Management: Advanced Tuning" by Greg Barnish, generally speaking for EFI:

- Best power is usually around 13.2-13.4 on the lean side. You're way below that.
- Best fuel economy is usually about 15.5 for cruising.

Now those aren't specific numbers for our cars/engines, but are generally accepted targets for most EFI. AFR isn't everything and timing is where a lot of the power is found, but your AFRs alone seem to be outside of the safe targets/range.

AadosX

iTrader: (10)

Right.. I Just find it very odd that these bolt-ons made me go rich. Either that, or my car in stock form was EXTREMELY rich and these mods are leaning it out some. Hopefully, assuming these numbers I'm getting are right, the test pipes will lean me out some and I'll be closer to the target A/F ratio ha.

Frostydc4

iTrader: (3)

You still have the OEM cats

0jiggy0

iTrader: (13)

No test pipes make your car run leaner.

indyz33

iTrader: (1)

i just dynoed my car last night. 08 hr wiht injen long tubes and hks hi-power.plus a crappy bully dog tuner with timing advanced 2 degrees. after the first run he said my car was running really lean towards redline. when he said 13.5 i was like well that is almost perfect is it not. being that 14.7 is perfect afr. Question is as i was looking at this dyno graph on this page..looks very similar to mine. Is it really not good to run at 13.5 at redline? I plan on adding test pipes and tuning this coming summer but didnt know if this was bad. I dont take it to redline on the streets so i feel i will be ok. oh btw numbers were 280whp/242wtq.

Ronin82

iTrader: (4)

All your bolt on upgrades wont optimley perform and neither will the power plant without the reflash. Only then will you see the full benefit. all your rich/lean problem can easily be solved. at least with my experiance from my DE

indyz33

iTrader: (1)

No i know i am not seeing full benefit of them right now. I was just wondering if it is gonna hurt the motor running it this way? i rarely take to redline as it is right now so i dunno just wondering?

Ronin82

iTrader: (4)

nah, you should be good. IMHO, the best route should be to Dyno stock, put bolt-on's on thenn Dyno, then last but most of all, reflash and Dyno. but your engine should be good in between stages. took me about 4 months to get everything installed before I reflashed, and I was good.