gotagetmyZ

iTrader: (8)

I've been running on the mods listed in my sig for a few months now and have been wanting to check my AFR for a while. Last week I finally drove and hour to the dyno shop and made 2 passes.

Other than the fact that my rwhp #'s were pretty sh#$#, the AFR really scared me.

I wish I could post the dyno results but I only got a paper copy.

As for my AFR #'s in 5th gear,
1st run (no fanin front of air filter) 15.5 @ 3000 rpm and gradually declines to 14.0 and spikes up to 14.4 right before redline.
2nd run (w/fan in front of air filter) 15.3 @ 3000 rpm and gradually declines to 14.8 then spikes up to 15.8 right before redline.
This can't be safe, can it?

It was about 98 degrees, 29.55 in-Hg, STD: 106 If this means anything

I run 93 oct.
Performed on a Dynojet Winpep 7

Could there be an error somewhere? Both runs were pretty much the same. Is it even safe to turn on the car with this type of AFR?

I've search and it looks like I need a reflash bad! Can I be driving my car around like this till I get a reflash? Please, some input would be very helpfull.

What other options do I have other than going back to stock?

Thanks guys


David

uplz4588

thats no good...

BlackZ33

I drive my car like this, seems fine, but I would suggest do reflash asap
or take off your test pipe.

Edited: but my a/f near redline isn't that bad!
Maybe shift before redline can be safer for you engine!
What method do they use to measure your a/f ratio?

Z BOY

iTrader: (41)

ya, putting the stock cats back on should help out til the reflash. i wonder which affects a/f more, the cats or plenum?

phunk

iTrader: (21)

you cannot always trust a tailpipe mounted wideband on a dynojet... if they do not regularly change the filter for the wideband air pump it can show lean readings. If its clogged enough that the doesnt really read at idle, this is a sign that it needs replacement. Not sure if you were paying attention or not, but something to keep in mind before you worry too much.

gotagetmyZ

iTrader: (8)

Yeah, they measured the AFR through the tail pipe. The guy even showed me how it works and everything. You might be right about it being clogged though. The upkeep of the shop didn't look like it was a high priority.

I will dyno elsewhere to get a second opinion and compare the two. I will pay more attention the the AFR while its in idle to see it it is reading or not.

I would install the cats back on but when I was installing the o2 sensors on the resonated pipes, one of the pipes had the o2 sensor bung threading done incorectly and I didn't notice till I had tightened the o2 too much. When I tried backing out, the freaken thing wouldn't come out anymore. I know if I try to remove that o2 sensor, I'll probably break something.

If I wasn't getting married in August, I would do the reflash but right know my hands are tied and my head barely above water.

Do you guys think the Apexi can do the job? Pros & Cons

The guy at the shop told me he would install it for about 150 dollars plus tuning

Thanks for listening!

David

Strife350z

iTrader: (4)

150 is a great price for the Apexi (I'm assuming you mean the SAFCII?)... but based on other experiences on the forum, I believe the stock ECU eventually compensates for any A/F tuning from piggy-back units

just curious to know actually... what model year is your car? 2003? Also - what were the HP/TQ numbers?

gotagetmyZ

iTrader: (8)

Its an 03 preordered. I had read that about the Apexi and was just curious to know if it was true or not. I'd hate to purchase it and have to tune it again because of the ECU changing it parameters.

I was afraid you would ask about the Hp/Tq #'s

I take my car out to the track often. I've ran 1/4 miles from when it was stock to now. Stock, my car would hit 14.6 consistently. For every upgrade comes several runs. There has alway been a noticible change in 1/4 mile times. I have manage to hit 13.9's at about 101 pretty consistently. So, the mods have helped.
All have been ran at night when it is cooler. Not 98 degrees like the dyno session

The dyno session would prove my observations "BS"

232.46 Hp 217.35 Tq

234.05 Hp 212.69 Tq.

I think the ECU is doing something to give me these numbers. Aren't people getting about 230 hp stock?

Anyways, I didn't mention it above but I did get a third dyno run in but in 4th gear. Just wanted to see what it did. Plus, it was only 10 dollars more.

AFR 15.3 @ 2500 to a 13.7 at redline
Hp 230.95 Tq. 222.29

Dave

Dave B

iTrader: (2)

Just how big is this spike? If it just lasts 100rpms, don't worry about it. Having a 15:1 A/F in the lower rpms which tapers off to 14:1 in the upper rpms is completely fine especially if you're using a tailpipe A/F sniffer which will usually show fractionally leaner A/Fs. Your mods have impacted the car's performance and your car is running marginally more lean. That's no big surprise. If anything, dump the Injen intake. Intakes are completely worthless on these cars and hurt performance if anything. The stock airbox already easily outflows what the VQ35 can suck in. Aftermarket intakes have a tendency to make a car run leaner compared to the other mods you've listed.

If you're A/F was dangerously lean, the knock sensor would pickup the detonation caused by the lean condition. If you don't hear pinging or knocking, then don't worry about. Definitely consider dumping the Injen intake though. I think your A/F will richen up a bit and you'll also make a little more power.

Zexy

iTrader: (55)

Good lord. Get a reflash immediately.

gotagetmyZ

iTrader: (8)

I don't hear no pinging or knocking. I've even tried listening to it next to a concrete barrier late at night on the highway but all sounds good. The exhaust is pretty loud though.

I'll change my intake location for now and start putting some money away for the reflash. Thankgoodness Its not my daily driver. (Old beater don't fail me now)

Sharif@Forged

iTrader: (92)

With a reflash, or an eManage setup, you can dial in your A/F ratio to about 13:1 and get more power and safety to boot. 14.1 at WOT is right about the point that the car starts pinging on 91 octane fuel, on a 85 degree day. With 93, you probably wont hear any pinging, but it doesnt mean that you car isnt mildly detonating.

Your breathing mods have definately leaned out your A/F ratio from the ideal level...pretty typical...but something to certainly address in the near future.

287HP

Most FI Z's are using piggybacks with no problems. Piggyback units work just fine for tuning a/f!

Alberto

iTrader: (14)

I had a/f over 15:1 lean and I drove my car like this for about 4 months, ran it at the track, in heat, even did a top speed run like this. I could feel the car struggling on hotter days in the upper rpm's, prolly because the ecu was pulling timing, this is also the reason I had bad dyno numbers, although not as bad as you. Bottom line you can drive around, but thinking back I wish I woulda taken it easy more, its been 20K or so miles since my very successful reflash and there is no damage that I know of. Get a reflash-I gained 10whp 12 ft lbs.

UnderPressure

iTrader: (4)

What he said.

O2's wear out over time and need to be replaced. Going to take a wild guess that they are still on the one that came w/ the dyno.

gotagetmyZ

iTrader: (8)

Thanks for all the advice everyone. Alberto, I guess I'm in like you before the reflash. 1/4 mi runs, high speed spirited driving here and there, hot hot 95+ driving for several months now. I will take the advice and take it easy till I get a reflash. I will call TS tomorow and see what they can do for me. I hope I haven't messed anything up!

Cheers,

David