I'm completely buffaloed.

After dynoing my car with just the Stillen intake, Z-tube, and HKS exhaust, I installed the Technosquare F-Spec ECU and ran it for nearly two weeks. Upon installation, I immediately noticed a big seat in the pants improvement in performance. The drive by wire was more responsive, the engine seemed to rev faster, and there seemed to be much more power at the mid to top end . . . all as advertised. Even a buddy of mine, who has driven and rode in my car before and after noticed the same difference.

So yesterday, I take the car to the same dyno shop, same tech, same morning time, same weather expecting great things. Well, here's what I got:

1) less hp
2) less torque
3) richer a/f
4) tech said he heard pinging under WOT, and thought maybe timing was too advanced

I have no clue. I will say that I have never heard my car pinging while driving under any load, so I'm not sure how accurate the tech's remarks are about that. Either way, I don't know what to make of a car that really does feel faster, but whose dyno numbers indicate the opposite.

Any ideas?

2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

 

I posted the dyno charts on "my ride". To view, just click on my user name, then "2004 sedan".

2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

 

Same gasoline? not just same station but same hour of refinery product?

The fallacy of dyno testing mods on different days.......for accuracy you must A then B then revert to A again.

 

Q45tech,

Not same day or hour for fuel. Same station and same 93 octane. I concur that the ideal situation is to A/B test same day/weather/fuel, etc., but this cannot be done when TS is on the Left Coast and I'm in Miami.

Are you suggesting that fuel lot variations (even from same station and with same rating) could lead to these results?

As far as weather, it's virtually the same every day during the summer in south florida, as long as you compare morning to morning or afternoon to afternoon, etc.


2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

 

I think I am seeing something that can be corrected.... I may be wrong, but you need to post (here) a higher resolution image of the dyno charts, clearly identifying which run is which.

I think I can help you
G

 

Does this help?

2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

301513-dyno3bw.jpg

 

OK, you are DEFINITELY running too rich, assuming that the TS dyno trace is the blue one. I can see that the dyno operator went full throttle at about 4200rpm and the o2 sensor displays the open-loop a/f ratio starting at about 4400-4500. He should have done what he did the previous time. Tell him to go WOT at 3800 rpm, and your AT will NOT downshift. Ideal A/F should be about 13.2 (at ~2500), gradually and smoothly coming down to 12.9-13.1 at redline.

Here is what I would do (just to be sure - before calling TS). I would do a 24 hour battery disconnect (for some reason that seems to give me better results than the other methods, but that could all be in my head), and get out and drive the car aggressively for about a tank of gas. Then go back to the dyno and see what happens. Then again, this may very well NOT change things at all, as your ECU was definitely reset on it's way back from TS. So if you don't mind spending hte extra money on the dyno and the effort resetting it, do this to be sure. Otherwise, you can probably conclude that for whatever reason your car responded differently to that particular ECU program. TS will correct this, I am sure. It sometimes hard to get it right right away, when you don't have your car at the shop.

Another point to consider, did the dyno operator take the readings from the tailpipe or pre-cat. The former may very easily give you leaner-than-actual readings. So your condition can actually be even richer than what's displayed. If I were you, i'd do a reset, than contact TS and tell him that you are a full a/f ratio point richer than needed (if this is confirmed)

Hope this helps
Gurgen

 

One thing I know about dynos is, you can never get the same numbers on different days, and to never trust what any dyno says. I have said on many occasions that dyno numbers are only accurate in the situation where like 10 g35's are dynoing on the same day with different mods and it wouldnt matter if everyone gets around 150hp, they will all be relative to the mods you have. I can go to the same dyno in the same weather, and their calibration could be different than before (90% of the time dyno's are calibrated off anyways) their fan could be farther away from your car, if they have a larger fan flowing more air you could get 15 more hp. Dynos are all BS. The only way to get half way accurate numbers is to calibrate the dyno the same day you are going in the same weather and make sure it is calibrated in 1-5 lb/ft of torque incremements. And make sure your SAE correction is right. I hope this was all understood. Ask any knowledgable engineer about this.

SCZ on my350z.com
2004 G35 Coupe 6MT | OB/Black
Premium | Aero | Splash Guards | XM
Z Tube | Pop Charger
Helix Test Pipes
Unorthodox Crank Pulley
Injen SES

 

you are absolutely correct ... my comments were in fact under the assumption that the dyno is spitting out halfway accurate numbers

 

As usual, SteveAreno is right! Group Dynos are really beneficial, but independent dynos are really a tough call. Some people like to do before/after comparisons, but there are so many related variables that it is tough to have any type of consistency to measure the small gains we're trying to see.

Example... You were probably hoping to gain ~10rwhp by adding the TS ECU. Let's say you initially dynoed 250rwhp (for easy mathematics). 10 rwhp basically amounts to a 4% gain. Now the dyno is probably only accurate to itself (on the same day, with the same set up) to +/- 3% (this is why some people see gains from grounding wires, adjusting the air intakes position, etc). Now factor in all of the other variables... was your car properly warmed up, gasoline grade/type, new oil on 2nd run, really old oil on 2nd run, fan speed, fan position, was it a windy day,etc... There's even round off in the machines applied to correction factors, read outs, etc... (infact the error due to hysteresis and round off error alone are probably as large as the gains you're trying to measure).

Basically unless you're going FI and trying to measure a real gain, the group dyno is the only semi-accurate way to measure deltas between mods. I sure wished more people would do the group dynos.

<font color=blue>The above statements are only my take on the issue. If you disagree with anything I typed then you are 100% right!</font color=blue>

 

Most don't understand that a Dynojet is not measuring HP but is measuring the time in 1/1000th of seconds for drum speed changes.
This time is translated via some formula in dyno computer to an approximation of torque then the torque number is converted to HP via HP= torque x RPM/5252.

The problem is the drum weighs less than the G35 so another correction factor is required plus of course air temp, barometer and humidity!

ECU expect a certain rpm gain per second in each gear because they are out ahead of the rpm in acceleration.......takes fractions of seconds to complete calculations so when faster than real world the ecu are wrong on the dyno.

Compare old ecu to new ecu on a Mustang [eddy loaded] Dyno you will probablt see a greater improvement when acceleration is slowd down to real world conditions.

 

Update . . .

To all who posted and pm me, thanks. Based on all of this information and a phone conversation with Technosquare, the problem is not the ECU but my testing methodology because I did not understand all of the dynamics and variables associated with the dyno process.

The bottom line is that my car really does feel more responsive and smoother with the ECU reflash. Since my goal is enjoyment from better real world performance, not from numbers on a dyno sheet, I'm OK with this. I misunderstood that the dyno is not as objective as I thought it was.

Of course, maybe ignorance is bliss . . .

2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

 

One thing that definitely would suggest for this very reason, is that you get an accelerometer. It easily and quickly measures performance times, for a quick comparison.

G

 

"Tell him to go WOT at 3800 rpm, and your AT will NOT downshift."

Wouldn't running it in Manumatic take care of this?

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5/Crawford Cats

 

no, this is actaully IN monumatic mode. Some trannies still downshift, and from the dyno chart, i can see that they prolly did run into this problem.

g