Cobb AccessPort for 370Z!

Denny McLain

Ended up calling Cobb in Plano and they directed me to Dan in Utah. After redownloading the software, everything except for the tuning software is working correctly. That I should get again tomorrow and see if I can figure it out.

Was in MI all last week for the Woodward Avenue Dream Cruise (absolute off the scale hoot) so I hadn't had a chance to play with it plugged into the car. Damn handy tool is all I'll say and I'd probably buy one just for the others things it does.

It answered one question real easy......the tach is off on the cars. At a showing of 5000 rpm; the car really is at 4800 rpm (typical of most cars. My Vette is also off) and at an indicated 8300 to 8400 rpm, it hits the rev limit of 8000.

A feature I didn't realize it had was fuel/air ratio readings. I'll log it and double check it for accuracy with the talepipe windband 02 the next time I dyno. If it is accurate, I'd say most people could do a half way decent driving tune. Once the parameters for AFR that the car responds most to are public knowledge, all you need to do is log the runs and make the corrections with the programming software. Like WOW. Something else I may try and verify on the dyno as in the past, I've done more harm than good trying to do a rolling tune.

Also found the air intake temp pretty handy. With the ambient temp of 97 degrees after a bit of driving through the local hood, the lowest reading I got was 108. I'd be very interested to see what others with the stock intake are seeing in comparison to ambient temps. Sounds like one part of the acid test to see how effective these various intakes are. The rule of thumb is 1% hp increase in hp for every 10 degrees of lower intake temps.

About time the big dog smelled where home was and is going in the right direction at least.

drisko

I have had no issues getting my computer to recognize the AccessPort and I've even viewed some data logs that I created from driving around town. I've yet to do any actual tuning with it though. The only thing I've done is just flashed it with the Cobb 370Z stock basemap.

Denny McLain

Your luckier than me. I was on the phone with Cobb three times yesterday and it's the tuning program that is still not installing. The first issue is both my main computer and main laptop are Vista 64. They do not have the software ready for Vista 64 yet. Lucky enough to have another laptop using Vista 32 and it will not load on that either. Basically ran out to time yesterday but will call them again Monday and let them troubleshoot the issue.

Also... A weather front came through the night before so I made a bee line to the original dyno (RPM in Lewisville TX) to get a better feeling for exactly what is going on with the car. Dyno sheets below.


370Z RPM run #10 - 317 rwhp std picture by dennylmclain - Photobucket

Note this is std hp and not SAE as per the first Cobb dyno sheet. SAE the car made 312 so either the car picked up 7 hp or it's a difference in dynos. It appears the car has learned in the 7500-8000 rpm segment and has picked quite a bit of power vs the fresh tune.

Only made two dyno passes (#9 and #10) as it was a learn vs a tune session, but the fuel/air readout on the Cobb Accessport is not accurate. Upon talking to the Cobb tech, he indicated the readout is based upon the narrowband 02 sensors of the car and would not be accurate but would be consistent for each vehicle. (it read about six tenths lower than the dyno wideband) I'll play with this some more in future sessions to see if it is consistent for my vehicle, but according to the tech each car would need to be hooked up with a wideband 02 to as he said each car would vary.

To not add too much material I didn't post the fuel/air but it varied between 12.8 on the bottom to 12.5 on top. Probably a couple more hp on top by leaning the car out some more.

On pull #10 we tracked the timing and found the midrange timing dipped thus the slight dip in the dyno sheet. Without knowing what the actual timing table is my only guess is either the car pulled out timing because it didn't like something or it's still learning the entire powerband. Next dyno session I should have that nailed.



Stock vs Bolt ons picture by dennylmclain - Photobucket

No brainer.....the car picked up 35-36 hp from tuning, intake, headers, cats and full exhaust.

Been hooted on because I've been very critical of manufacturers dyno claims. Well.... here ya go. Hoot on this......... as this is real world results from someone with no financial interest. About what I expected and typical of what most cars get from bolt-ons. Real shame what people do and say to get ya to buy their stuff.

Denny McLain

After three calls to Cobb, I finally got the AccessTUNE program up and running. Not necessary overly complicated ,but a matter of learning new software and how the ECU works.

The biggest current issue I have is trying open the Cobb Plano tune to try and figure out why the logged timing/power output is so low in the midrange. Not sure exactly how it works, but Cobb in Salt Lake City may be different as the tune from Plano was locked and wasn't able to access the file. I can access the stock file fine, but the tuned program requires a new file sent in the Cobb universal tuning program.

In viewing the stock program the timing program is pretty uniform which probably means the car is pulling out timing. Now to get a copy of the current tuning program and see if I or Cobb in Plano can figure out why.

Z eliminator

I have the Cobb but the sent me the race tunner program for a 6 mt and mine is a 7 AT.
I spoke to Dan and he is fixing this issue.
I have a stillen G3. berk cats stillen headers amd stillen CBE.
Do you have any maps for these mods.

thanks

Denny McLain

Sorry! I didn't realize you had posted something directed toward me. The answer.....yes, and in fact I reporgrammed the car today leaning out the top end slightly. Problem is mine is a six speed but your welcome to my fuel tables.

Denny McLain

I'll make it as easy as I can:

Stock fuel tables

2.6 3.5 5.5 8.3 9.6 11.5 14.3 16.6
2800 1.00 1.00 1.00 1.00 1.00 1.00 1.00 .80
3200 1.00 1.00 1.00 1.00 1.00 1.00 1.00 .80
4000 1.00 1.00 1.00 1.00 .90 .86 .80 .80
5200 1.00 1.00 1.00 .85 .84 .82 .80 .80
6000 1.00 1.00 .90 .84 .83 .80 .80 .80
6400 1.00 .92 .90 .82 .78 .77 . 77 .77
7000 1.00 .89 .88 .87 .87 .77 .77 .77
7200 1.00 .89 .85 .77 .73 .72 .72 .72


Cobb tables for the same mods only me adding 1% 6000 and above:

2.6 3.5 5.5 8.3 9.6 11.5 14.3 16.6
2800 1.00 1.00 1.00 1.00 1.00 .97 .92 .89
3200 1.00 1.00 1.00 1.00 1.00 .97 .91 .89
4000 1.00 1.00 1.00 1.00 .91 .90
5200 1.00 1.00 1.00 91 .88 . .91 .91
6000 1.00 1.00 .90 .89 .89 .90 .91 .91
6400 1.00 .92 .90 .88 .88 .88 .91 .91
7000 1.00 .89 .88 .87 .87 .88 .90 .90
7200 1.00 .89 .88 .87 .87 .87 .88 .88

Here ya go. Adjusting the rev limit and speed limit should be a slam dunk.

Denny McLain

Starting to get a little deeper into the tune and how the Cobb system works. As I become more and more familiar with it, I'm starting to warm up to it a little more. (still wish I could play with the onset of the fans.......hint, if anyone is listening.)

When the car was tuned at Cobb they did not touch the timing tables and again, each car is different and these cars may may not like much timing. The stock timing tables still look very conservative to me. I logged a couple of second gear passes and the car is pulling out timing in the midrange and even more so when it gets hotter (like a 203 degree water temp vs 184). For poops n grins to see what would happen, increased the timing in the same range that is being pulled out and made a couple more runs. Still pulled out timing from what's in the table, but the log showed an increase in timing in that range.

The computer might be seeing what it thinks is a lean spot and pulling timing, so I added a bit of fuel where it's pulling timing out plus increased the overall timing by 2-3 degrees. Will drive the car and let the computer learn and also to see what's going on.

Hope to eat my prior words as in the past there wasn't much gained in timing ,but these tables are almost half what a Ltx small block is tuned for.

Denny McLain

I'm dewarming already. What's up wid dis?

After adding timing, tweaking the fuel slightly, driving it for a couple of days so it can learn some. Today, going out logging a few 0-80 runs...... the logs look almost exactly the same as before the tweaks. Just how in the hell do you make these cars respond?

Somebody! Anybody! Help me Obi-Wan Kenobi!

Going to make another trip to Cobb this week and see what they say . In the meantime, try and reset the ECU to see what happens. This really is getting much more difficult than I thought it would be. I'm back to lost all over again.

What good is any software if the car doesn't respond to the changes?

1slow370

does the 370 have factory widebands? i know some cars do now.

westpak

the Z has had widebands since 2004.5 model

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westpak

I think there are just some settings that are not accessible that owuld help tune and neutralize conditions while you tune that affect timing.

we played around with the intake temps and actually put an adjustable resistor in the line to control the temps the ECU would see and you could see 5 degrees being taken out as it got hotter, so without knowing if there are similar tables for oil temps we knew we may be fighting a tough battle to get consistent results. It is a good product/concept just needs a little fine tuning to get more control over what is going on to be able to tune and know you have consistent results.

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Denny McLain

Agree a thousand percent as I've had an opportunity to study the logs and mull over it some more. Very perceptive and smart move on your part by adding the resistor and that shows real experience. Excellant!

Not logged the intake temp but what I noticed is when the water temp was lower, the car ran more timing on its own. Initially I thought it was me adding some timing, but something is obviously overriding the timing settings. The tuning timing tables at higher rpm says 26 degrees, but I've seen 28 degrees. Why would it be more? Pretty crazy.

On other software I've used, in particular there are offsets on the fuel for water temps. Guessing Nissan has tables that does the same for timing. Again, just for giggles I changed the Ignition Hi Det tables to see what happens

For right now, being the ECU pretty much does what it wants, think I'll just set the Accessport aside until they make a little more progress. Save my dyno $$ for when the sun is shining so I can actually make a little hay for a change.

Again, very perceptive and excellant post.

Denny McLain

Interesting....When I called Cobb about the fuel/air being different than the dyno's wideband, they said they were narrow band. No wonder they they cost $425.00 each.

westpak

Thanks, I think that once they crack those other tables that are coming into effect you will be able to tune and know what you are getting.

yeah the front ones which provide the feedback to the ECU are wideband and the rears are still narrowband

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