hi nj i see you have a lot of timing up top just as i do!

 

Yeah, this is the off-the-shelf Shiv map timing. But I was more concerned with the AFR. Just like your off-the-shelf map this map runs lean.

You need to add 4% fuel to your entire AFR map and bring it down by 1 AFR point like I did. Make sure that you zero out all the hexes that become positive when you add fuel.

 

thanks nj!

 

I am begining to have a change of mind on whether Shiv's off-the-shelf map is lean or not. This change began when I read these two articles from Klaus Almendinger of Innovate fame.

http://www.innovatemotorsports.com/resources/myths.php
http://www.innovatemotorsports.com/resources/rich.php

The crux of his argument (as I understand it at least) is:

1. The best burn for gasoline and air happens at a mixture of around 12.5:1. This is where the fastest burn happens, most energy is released, and most power is produced. A leaner or richer mixture produce less power.

2. IF your combustion chamber has good design, ie, it allows for a fast burn of the mixture, then it is possible to reach that 12.5:1 ideal burn mixture.

3. To reach that ideal burn mixture, you need to retard timing rather than advance it. Basically, you lean out the mixture to 12.5:1 and retard your timing until you start losing power.

IF that is correct and Shiv is following the same line of reasoning, then it is understandable that Shiv wants to keep AFR as close to 12.5:1 as possible.

Here is an overlay of my stock AFR/timing and Shiv's off-the shelf map. Both were run on 93 octane gas.





The dotted line is the stock map and the solid line is Shiv's map. You will note the following:

1. While Shiv's map has higher boost between 3500-4000 rpm, the AFR is lower or the same as stock. That is where the highest likelihood of knock can be detected by the knock sensors.

2. From 6000 rpm and up the difference in boost is roughly around 1 psi.

I think Shiv's strategy is to keep the AFR as close as he can to 12.5:1, keep a safe boost level and back off the timing.

 

12.5:1 on pump is too lean especially since Vishnu claims these are open track maps.

When I called him on this he said 12.5:1 at peak torque is fine because there's not much timing advance and you're only there for a second or two. After researching this I found that to be a standard evo tuning method. Running 12.5:1 after that is not safe and I highly doubt his maps are intended to run that lean.

Luck for us the stock ECU has VERY AGGRESSIVE safety features.

 

12.5 works on a car without boost. on an evo you Might have 12.0 at about 5 psi or less. most tuners will be in the high eleven's by the time they are into boost.

the higher the boost the richer the fuel.
look at it like this
idle, cruise,= 14.7 this is clean burn low emissions
12.5 is a starting point for a NA car at wot or an evo before boost
once you get into boost you will be ramping (generaly) from 12 at .1 psi to 11 at 19 psi (in an evo)

give ot take a bunch

here is the key element: afr means little to power level, an afr off by nearly a point will lose a tiny bit of power (going fat). A FEW DEGREES of timing will lose HP in a hurry.

 

I just noticed this, why do you need a "field" (what is that?) harness to install the Zietronix?

 

I missed that too Here is a link to the archives of our Spec V.

http://www.nissanperformancemag.com/.../perfspecv.php

My brother and I did all the work. The next write-up we will tune the car with an SAFC II. I have logged the AFRs on the car and the NA Spec V runs at 10.8:1 AFR This is as rich as some stock EVOs run. We want to lean it out to about 13:1 and see how much power we can get.

 

I hear you Jeff. I am not suggesting in any way that people go out and lean their cars to 12.5:1. I am just trying to figure out Shiv's reasoning for such AFRs. If as Klaus is telling us that between 12-13:1 is where the best burn is, then it makes sense that Shiv is trying to hit the point. The issue that I see is this: Is Shiv backing off the timing enough to allow the cars to run safely at 12.5:1?

I wish that Shiv will participate in this and give us his thoughts on this matter.

AGAIN, please do not take what I say as license to run that high AFR.

 

I think we are running leaner than normal because we have non-standard vishnu mods.

In all honesty I'm not even sure what PSI vishun expects us to be running.

 

Hopefully Shiv will weigh in at some point and fully explain what's up, then again maybe he won't (it is a somewhat proprietary process that he uses). I have be lucky enough through my career to work with many many top tuners in several countries and driving several platforms from tuned exotics costing over $500k to Miatas to tuned motorcycles all of course driven and ridden as hard as I can on the track. From that basis I can tell you the guy knows what he's doing plain and simple more so than anyone else I've encountered at any level (and remember I work for pro teams who use the biggest names in the business). I use him to trouble shoot every thing I drive and race (even when he's not the official tuner of the car).

I can also tell you from my evo experience that the maps are absolutely safe for open track use. My car has countless track days tuned to the same AFR's as his sea level maps and it has been consistent and very very fast. I always run straight 91 BTW and many people use his maps that I know with no issues at all running track days all over the country.

Just look at his "track" record and go by that, my car does not pull timing on the road or track (I can feel when it does) as long as I have good quality 91 octane in it.

Lots of smart guys on this thread so I wonder if it's just "intellectual masturbation" for those involved ... Nothing wrong with that mind you , I just don't think there is an actual issue here

 

I do not know if the TBE would make a difference. The map that I downloaded is intended for a car with a dp and cat back and stock filter. I already showed that the K&N did NOT make a difference in AFR, at least on my car. And since I am measuring AFR at the dp, then the stock cat should not make a difference. The kind of TBE we use should not have an impact on the AFR. All of the TBE that I have seen are between 2.75 inch and 3 inch afterall.

 

Oh Yeah, I remember reading some of those articles. I enjoyed them.
Brings back memories. I even had a Stromung exhaust and lots of other
similar modifications.


BTW ... Some guy's on the Nissan forums have showed good results leaning out the QR25DE with the SAFC2. Other than the QR-Pro from Stillen, there doesn't seem to be much of a choice for engine management.



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Yes, there's no way I wanted to make a bunch of splices into the factory wiring.
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I also read those articles on innovative's website by Klaus Almendinger.
There are some interesting and great points in that article.

Shiv has years of tuning experience and he knows his stuff, most everyone knows that.

Shiv's tuning methods do seem to have similarites to some of the concepts
in those articles.

I guess I prefer to stay on the conservative side because I've read enough
post about blown motors, spun rod bearings, etc... especially on 2005's.

With that said, I didn't mean those blown motors had to do with any specific
tuner or product. I mean it seems once you start tuning and modifying,
there is always an element of risk involved.



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