Cobb vs UpRev

wstar

That is kinda weird. Looking at the rpm gaps, which are 400, 800, 1200, 800, 400, 600, 200, this is my best guess:

They expect you to tune some other engine parameters to get the big center area (1200rpms from 4000 -> 5200) about right for that whole range, and then you see the 800 and 400 gaps arranged symmetrically around that, basically meaning "the further you get away from this center, the more adjustment you'll need here". The oddball part is the very upper end, which breaks with this symmetrical hill pattern and steps out by 600 and then only 200.

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Journal thread / Car setup details

Denny McLain

My feeling also and really why I posted it. By pure luck I need to change it the most where there are the most points. Guessing it may have something to do with the ECU as I don't see the logic.

1slow370

The target AFR is only supposed to be a guideline. It tells the ecu about where you want the AFR to be so it should be set around 12.5-12.8 and leaner down low near idle midrange. You change the MAF tables to tweak how the engine runs or the VE tables which it doesn't look like you have access to. Target AFR is there to tell the ecu when to start correcting itself. You need to change the air flow tables to make the ecu run right in the first place in order to give you the afr values you want. Both tables need to be changed in order to work together but the Target AFR table shouldn't have to be changed that much maybe a few points here and there.

Basic guide to nissan tunning
http://www.plmsdevelopments.com/file...ing_basics.pdf

Denny McLain

Except for the fuel/air guideline ratio's, that is basically what Cobb is saying to fine tune. The gross tune does come from the fuel tables as I have both the stock one and the Cobb table to compare. No one seems to know (including Cobb as Calvin admits they are in a learning curve) or if someone does, are not willing to tell what is the best general AFR. Cars will vary and it's what that particular car likes best. (My Corvette liked around 13.3 to 1 - FYI, Pro Stock runs in the mid 14's - Forced induction in the 11's)

These cars appear to be different if that is the way to go as that is not what the tuners I'm used to dealing with do and certainly not what I've done in the past. (Yes, I'm an old Corvette, Chevy guy but owned a lot of imports also)

It used to be the first thing I did was either buy a larger Billet MAF or port the existing one. (More flow is better right?........ Only if it needs it Home!!) Found out later it made them harder to tune. The current trend among the people I talk to is to stay away from playing with the MAF, use stock tables as the only way to go.

Different strokes for different folks and what works.....works. An old dog can change his stripes. I'll read the guide as the software in it looks more like I'm used to as the Cobb software is certainly different. Certainly is a learning curve to all of this.

Thanks for the guide.

1slow370

you can always do what we used to to find out what works. Simply find someone with a technosquare tune as it makes the most power right now and rip it from thier ecu then copy and paste baby Used to do it with .bin from the mclaren special grand prix tgp turbocharged 3.1 l engine when running forced induction on our cars. I'm sure you could rip the nismo tune too.

Denny McLain

I doubt the Nismo tune is nothing more than raising the red line. I'd be very curious as to the Technosquare tune as I'm still wondering if the Cobb tune helped or not. (yes, the air/fuel changed) Or...... is it a matter of different dyno's or...... the computer somehow needs time to learn and is holding it back as the car did not immediately respond. May make another trip to Cobb and see if I can get another baseline on their dyno to compare apples to apples.

1slow370

Ok and a minor update on the Cobb vs. Uprev issue Apparently Uprev exists they just won't give it to us yet but it is in fact in use and will say no more than that for now.