civic4982

iTrader: (9)

So I had my car tuned recently with a Dynojet 224x Dyno. While on the dyno and using the same bung that I use to normally run my PLX Wideband the AFRs on the Dynojet read between 11.5 and 11.7 almost the entire way in 4th gear from 3500RPM to redline on WOT. At least I think that's where he used it. He never compared it on the dyno to my PLX Wideband so we're unsure of their discrepancies. The PLX Wideband is only 2 months old and has not been damaged in anyway that I know of.

When I took the car to the street though my PLX Wideband continues to read anywhere from below 10 (saying RICH) at some points to running up to about 11.1.

Why the HUGE discrepancy?

On the Dynojet Dyno the car was making 355 rwhp. Took it to the track last night and the car ran a 14.4 @ 98 MPH with a 2.3 60', a 9.4 1/8th mile, and a 78mph 1/8th mile trap.

I have verified this PLX prior to this tuning with a Cipher cable and it reads almost dead on with the car's stock widebands.

The car does not bog or misfire and drives smoothly throughout the RPM range.

I'm not sure what the load settings on the dynojet dyno are but could this large discrepancy be due to a larger load on the dynojet than real world settings?

I have no idea what to think here b/c the numbers don't add up. I'll be taking my car back to my tuner but not for another month at which time I'll be back in town.

No cloud of black smoke billow out the back that I can see even when it runs "RICH" (AKA below the 10 AFR that the PLX wideband reads at which point it just outputs the word "Rich")

I'm confused, can anyone help?

civic4982

iTrader: (9)

oh yeah and my tuner uses a dynojet 224x with their attachable dynojet AFR reading with the wireless setup to read all the values.

Here's the final dyno sheet we had. I don't know how from this to my PLX Wideband we have such a discrepancy of > 1.5 points on AFR richer on my wideband than theirs.

wannabuy350z

iTrader: (27)

their sensor must be dirty, and think of how much carbon build up those sensor get at the end of the exhuast and off the downpipe compared to the end of the exhaust your a/f will vary

athenG

iTrader: (2)

wow.. 98mph 1/4 mile trap!!! A stock 350z would've beat you silly with that.... Anyways, so they used the same bung as your WB and not a tail sniffer? It is a given either your WB or his is not calibrated right. I'm more surprise you didn't even break 100mph trap. What was the condition? Your Dyno # doesnt match your 1/4 trap speed...

civic4982

iTrader: (9)

^ that's precisely the reason I posted it.

It didn't make sense. The trap speed is often a good gauge of hp.

The conditions were a cool 76 degrees fahrenheit night and somewhat humid but really not anywhere over 70% from my guess.

The 1/4 mile run was the only run I was able to make since I came there and the lines were so long and I had an evening date planned to meet with some friends. I wanted an hour for the first run and then just bolted.

I THINK he used the same bung. All I know was that there was a wideband disconnected and another one in its place. He could've used the one after the cat for all I know.

Regardless of where he collected his data from, before or after the cat, the discrepancy should only be about 0.5 AFR difference not a full 1.5 points.

There's definitely something strange here. I'm going to purchase another cipher cable and see what my stock widebands are reading to see if they match with my PLX Wideband. (I knew I shouldn't have sold mine doh!)

OR

I'll borrow someone's Innovate wideband or another type with a cigarette adapter and put it in my car for temporary testing to see what it comes up with.

I'm leaving today and won't be back to drive my car for 4 weeks.

Strangely it drives perfectly fine and doesn't bog or stutter or anything.

I have no idea what's going on with it and why those readings are so low. It may just as well be that my O2 sensor is damaged but often when those get damaged it won't read anything.

If this helps : my cruising and idle read correctly at around 14.5-15.0 with variations all going right around stoich.

civic4982

iTrader: (9)

http://forums.stangnet.com/567417-tr...ined-here.html

interesting read.

it estimates my car at 209 whp with the 98mph trapspeed considering that I made a weight estime of 3468 lbs.

athenG

iTrader: (2)

do you have a 350z or G35? I see you in Driver so if you have a G35 then I'm pretty sure you weight more than that. I weighed 3700lbs with me in it. I had less that 1/4 gas in my tank, no CAT, no Muffler, no spare tire, I have the extra weight from my turbo but you are also FI'd... There are many Trap to WHP calculator and with your trap and weight, you are more on the 22xwhp....

WTX350Z

iTrader: (8)

But the # should be more like 3XX-4XXWHP shouldn't it?


Civic, I knew you'd regret selling that cable.

I say do exactly wat you planned on, use someones Innovative WB, and stockers to see which 3 agree most with each other. at this point there's no way to know which one is telling lies. does it smell rich? I know this isn't scientific, but still.

civic4982

iTrader: (9)

you're absolutely right WTX350Z. The number should be closer to 350 rwhp.

yu're also absolutely right that I regret selling that cable.

I'm buying another one tomorrow with 4Shizzle so he can use it and I'll take it back with me to Texas. I'm in the DC area now. Once I get back I can test it out and see what my stock widebands read.

I don't know if it smells like it has fuel b/c it doesn't run rich until it hits boost. Otherwise it drives fine.

There's no way to get any answers until 1) I get back to Houston and test it with another wideband or my stock widebands with the cipher cable 2) someone drops my car off at the shop and the shop verifies it all.

I really do think it's just that the tune didn't take.

athenG

iTrader: (2)

What? A car that weight 3500lbs and trap 98mph should have 300w-400whp? Stock G35 trap around 98mph-101mph so they are making 400whp?

WTX350Z

iTrader: (8)

geez....NO.....go away
a Supercharged Z/G should be producing between 300-400HP...

athenG

iTrader: (2)

So why are you quoting me?
Great guess Mr. Nostradamus he has a dyno that said it pushing 355whp!!! I said his trap indicate that he's only pushing 230whp and not 355whp. I asked him if he let go of the gas and he said it was a clean run.

civic4982

iTrader: (9)

yeah so we've decided that realisitcally the car is omaking in the mid 200s right now at best even if I'm an awful driver.

so, there's something wrong with the tune. the conclusion so far is that...

my girlfriend will be dropping my car off at the tuner for them to work on it at their convenience over the next 4 weeks while I'm gone.

athenG

iTrader: (2)

Maybe something after the dyno run that affected your tune. I forgot to ask if you are boosting ok. I hope you find the culprit coz even with bad launch or a misshift that you should trap higher than that. I had 2.67 60' and also misshifted on 2nd and still trapped 106mph. This was also with my heavy 19's and temp of 80F and humidity of about 65%.

rcdash

iTrader: (18)

What EMS? What's the rest of your set up? Esp fuel system set up. I think you're running rich as your wideband is telling you. It could be a faulty injector or fuel pressure regulator or pump.

On the other hand fuel could be just fine. So what's missing? Air. Boost leak? It's a good explanation for a loss of power and running rich. If you give more info on what gauges are reading properly (boost, fuel pressure, etc), maybe we can take a better stab at the problem... Basically too little air, too much fuel, or no spark. Just gotta find which it is and the underlying problem. Good luck.

civic4982

iTrader: (9)

boost ran fine on the dyno and AFR ran fine on dyno then once taken on the road AFR rshowed rich on my personal wideband.

No boost leaks found. No air blockage found.

No other gauges on the car except AFR.

Car is not stuttering or bogging at all. No smoke coming out the back.

Someone suggested that it could be a heat soak issue while on the dyno and the tune was made richer and now it runs that way b/c it was tuned when the air intake temps were too high.

Sorry thats all the data I have.

rcdash

iTrader: (18)

colder air is denser and usually requires more fuel, so it should be running leaner now, not richer.

Which EMS?

civic4982

iTrader: (9)

^ that's what my conclusion was too recently by the same logic you had.

the EMS is Unichip.

WTX350Z

iTrader: (8)

Quoted you, b/c you tried to use your everending knowledge to smart off to me about HP numbers. mainly with your little "so a stock G35 makes 400whp?"



what? there are too many variables. the end...your little calculator is 80% worthless, give or take 20%.

trying to diagnose via internet w/ no reliable data is not worthwhile...civic has a good plan by getting car to a shop.

civic4982

iTrader: (9)

hey guys, let's just let this thing go and not let this get into a flame war.

no big deal.

yes it isn't trapping the right speed and the trap is more indicative of mid 200 rwhp.

yes I agree it's going to be the best idea just to take it back to the tuner and let them figure it out as well as verifying my AFR with another wideband or my stock widebands via cipher.