I understand all that, but I am honestly confused about how you could gain hp and lose torque from one dyno to the next. This is not a bash, just a honest question. Does it have something to do with the tune?? Maybe it pulls timing on the low-end or something??

 

Our dyno is a 224 and the other dyno is a 248

Our dyno runs Winpep 7 the other dyno runs Winpep 6

I do no know why the other dyno did what it did but that is the way it goes. Dynolab is considered by most around here as a bench mark dyno because it has been around so long and everybody in Atlanta has strapped down on that dyno. Hell I have tuned over 100 cars at Dynolab.

We strapped our car down yesturday to check it one more time and same results.

 

This just goes to show that all dynos to not product the same results.... As Mike mentioned... WinPep 6.03 Vs WinPep 7 could have alot to do it. Also the dynos being 224 Vs 248... Lastly, The car was hot as heck @ DynoLab... We usually pick up quite a few rwtq with a couple minute cool down....

Im sure I could have hit 3 other dynos in the area and made 3 different #s .... Dynos are a tuning tool.. Nothing more.. We simply wanted to compare our dyno to another reputable dyno out there as people are always saying our dyno reads high.... Doesnt quite look like that after seeing the comparison

 

Well I got the HS rockers last night. A big thanks to Mike @ TEA for the great deal. As promised I logged both before and after runs with HPTuners (attached to the post). Run A is with the YT rockers and Run B is with the HS rockers. Full throttle runs for the YT rockers start at frame 3238 and 3853. Full throttle runs for the HS rockers start at 3691 and 4382. Ambient air temp had dropped about 6* between runs (took about an hour to swap the rockers).

Both setups generated a few degrees of knock retard on one of the runs. The YT's generated slightly more from what I recall. Looking at the ST and LT fuel trims the HS rockers look like they run leaner.

Driving impressions. The HS combo drives noticeably smoother. The most noticeable effect was in the 1100-1500 rpm range. The cam surge or chugging when not under throttle is largely, if not completely, gone. I was quite surprised at this. I'm wondering if the geometry on the YT setup was causing way too much preload which in turn caused this behavior (to much preload causing the valves to stay open and cause reversion pulses?). Up top the motor felt smoother as well. I don't trust my buttmeter enough to say it gained a lot of power, but it did feel stronger. Could easily be my brain wanting it to feel stronger. So the big question is was this the solution or is there more wrong here? Take a look at the logs. Let me know what you think.

 

Get it back on the Dyno. I am wanting to run the Harland Sharp Rockers or Jessl Rockers.

 

If only FLP wasn't 5 hours away. Someone needs to open a speed shop around here. I think there is at least one dyno somewhere in Des Moines. I may try to find it.

 

Hi 99C5JA,

I can't read your logs!!!

Can you send them on my email address?

Christian

 

Yeah they do something funky with attachments. I zipped them. So you should be able to open the .zip files to get at the logs. Thanks for checking them out.

 

For what its worth, my opinion and obvservation.

WOT:
1. Your Bank1 O2 sensor at 100% throttle is 40mv off the other side at points. Could this be caused by valve adjustment or possibly an intake leak, sucking air for some reason, bent valve, missing rubber ring on intake, or even a bad o2 sensor? I think this is more than it should be. There are times your bank1 is at 845mv. This is WAY TOO lean. A stock vette for example is around 903-911mv or so. In my opinion, anything less than 890 is going lean and even at 890 you'll get good throttle response and slightly less power up top. At 944mv you are losing power from enrichment and this is evident in bank2. So bank1 is leaner than should be and bank2 slightly richer.

2. Your MAF maxes < than 42lb/min from a stock LS6, at around 39. That seems a tad low, then again you are still diagnosing the problem. Is the MAF mapped for the airbox and no leaks?

IDLE:
LTFT are are low as -9.4%. That indicates your pc is programmed to deliver too much fuel at idle and in some case STFT are extremely low too. I am referencing this point of idle, but I believe as you transition throttle, you will see problems, enrichment you may not want.
As you know this situation can be corrected many ways, MAF MAP to INJ FLOW RATE to be the easiest.

To summarize, the only thing that sticks out are the really low trims off idle.
I'm not so sure thats responsible for the hp you are looking for, but there is a lot of power in that area. I do think I would get those LTFT at idle to around +5%. May consider leaning the mixture on bottom approaching no change at the high point of the MAF or FUEL INJ slope. Let us know what you find.

 

Thanks for the insight. I can recheck the intake, but I am sure all the gaskets are in place. I cleaned it well before reinstallation. Since these are the original O2's the sensor may be the culprit. Looking again at run B I didn't see the B1 O2 hit any less than 890, but I could have missed it.

Could the idle trims be fixed by scaling back on the VE tables in the 800/1000 cells? Or would scaling the PE Fuel Multiplier vs. RPM in this range be a better bet?

When you ask if the MAF is mapped for the airbox do you mean has the frequency been altered? The MAF table is still running the stock values. The filter and MAF are sealed. I can recheck that the clamps are tight.

Thanks again for the help.

 

Here is a graph of the O2 sensors from both datasets A and B and also a stock zo6 for reference. I would consider replacing 1 or both sensors.
They should in theory be somewhat close at WOT as you can tell from the stock z data.





PE vs RPM is only effective in WOT mode and will not change the low end.
Note, how the dyno data starts at ~3,000rpm. Hard to tell whats happening before. You could probably adjust the MAF data and smooth it in to the current curve. Look at the log and make sure you aren't in PE mode. For a zo6, ~25% or greater TPS at 2800rpm and up you are probably in PE mode. So, I would look at Hz values at < 10lb/min (< 3500hz)
and decrease them until the desired mix is obtained. Feather data in the up part of the curve.


Yeah, I was trying to figure you how you compensated for your airbox. They throw off the MAF quite a bit and cause lower than expected airflow reports to the pcm. In the case of my stinger, around 14.8% and I bet yours was similar.

The more I look at it, the more I think with a few slight adjustments and possibly a new o2 sensor if thats the problem, your engine is going to gain
power and be much more responsive.

Note, I realize its hard tracing down a problem, hope the info provides some insight. Also, I realize some of the guys like leaner or richer mixes. I tend to go w/the stock A/F ratio. That and testing of the o2 range is how I came up w/the range of use.

 

If you don't mind my asking how did you plot the O2 data like that? Are you loading the data and throwing it in Excel? It would be handy to know how once I get the sensor swapped.

As far as the idle goes I'll try decreasing the airflow values in the relevant cells by a small percentage until I can get it somewhere more sane. Don't know why I was even thinking about the PE table, must have been brain haze.

Thanks again for the help.

 

Export data from HP Tuners as a CSV, then import to Excel.

 

Thanks, that's what I figured. Probably swap the O2 tonight.

 

Ok, ITS NOT THE 112. I just got my car running. It pulls hard all through the powerband. more to come..

 

I got the O2 sensor swapped. Looks like the sensor may have fixed the issue. I need to do more logging to know for sure. Glad to hear your car runs well 03EBZ06!

 

Any news?

 

Not to rain on the parade of the guy having problems, but here is an update from my TFS System:

450.4rwhp/424.0rwtq

02Z06 w/:

HallTech Stinger Airbox
224/228-112+2 Comp XER
TFS TEA 61cc heads
1-3/4 Kooks with Cats
7.5" pushrods
0Z700 Textralia Clutch

If I can get some sticky tires, its going to the drags on Sunday. Just wanted to pass this on. For me, its all in the 1/4 mile MPH, so the final test isn't done yet. You would never believe how docile the car is.

 

Sorry if it was already mentioned...but what is the lift on the cam you are running?

Are you running the ls6 intake and stock TB?

 

0.581" intake, 0.588" exhaust. The intake and throttle body are stock.