5* at what RPM? if it's at 6000-7000 then obviously something is really wrong.

Change anything else recently? How much mivec advance at the same rpm?

What 2byte load? Wideband reading correctly?

I've found (by accident a couple times) that the IX can run a really lean AFR for a pull or two (think 12.1) on 91 oct in the low and midrange but then it will always say "No thank you" at around 6k.

 

leak test

 

Yeah I have the timing at 1 at peak torque, and then it gradually increases up to 5 by redline. The knock always comes on at around 6-7k.

The last mod I did was the turbo kit and the spark plugs. I tried many different mivec maps trying to get it working with anywhere from 0 - 19 in the upper cells, but the results were pretty much the same, with maybe slightly less knock when I had it around 10 so I left it there.

It usually stays around 250 load at 23psi. At idle the wideband reads correctly, so I would assume it is working properly. Also I just recalibrated it a few days ago so I dont think that is the issue.

My af is right around 11-11.2:1 up until 6k when I dipped it down to about 10.8 trying to get rid of the knock.

Even at 21psi I could only run about 7 degrees up top before encountering knock sums of 5+.

 

And you fuel map looks normal? You aren't having to richen it up abnormally or anything?

What spark plugs and what gap?

Are you logging 2byte airflow?

 

Post/PM me a datalog.....also tell me the total weight of the car to include the contents (people, extras, etc.)....i can get you a DataLogLab plot which can be pretty close....

I run 23lbs on my car and a few other cars out here on 91oct....timing from 4-5* @ peak tq to 11-12* @ peak horsepower....

If the car has stock injectors, the fuel map @ WOT should be between 9.3-9.8 for an 11.2 AFR depending on what intake is on the car...

BTW how old is the wideband sensor? Has it seen racegas? I have seen this personally with a wideband sensor that went bad....i like to cycle my sensors every 6 months.....

 

Nope not having to richen it up abnormally, I had to lean it out a bit.

I am running the denso iridium 1 step colder gapped at .023. I plan on running higher boost with meth injection in the near future, and I heard a tighter gap would work better for that.

In response to alan's questions:
I would be happy to post a datalog, but I am not sure where I should host it.
I am running the denso 720s and they are scaled properly.
The wideband is only a few months old and it has only seen 91 octane.

 

The thing with incorrectly calibrated widebands is they can be accurate at idle but be out at the extremes.

I would go to a real dyno to check your AFR's

 

I will try calibrating it again tomorrow and see if it makes a difference.

 

LC1? make sure you do a FREE air cali - ie either remove it from the exhaust or don't drive for 12 hours...

 

Yeah its the lc-1. I am going to do it tomorrow in the morning after it has been sitting for like 15 hours. That is exactly what i did last week though so im not sure why it would have changed. We will see though.

 

Try using NGK plugs instead of the Denso ones. I had a problem with inconsistent knock using Denso plugs. I changed back to NGK and the problem has gone. I don't know why this should be the case but it could be worth your while trying it out.

 

what is your IDC at ?

 

The reason I would suspect is heat transfer. The spark plug also acts as a heat conductor to pull heat from the combustion chamber. My guess is the NGK has a much better transfer ability.

 

I have a better technique....try this.

get the car up speed in say 5th gear, leave it in gear, let off the gas, the throttle body closes, the injectors shut off and the engine becomes a big air pump. Wait a few seconds then hold the calibration button.

viola, you're calibrated

 

Member you are running cams though. Im running similar numbers, 3* at peak torque and 6* at high rpm. Didnt perfect it completely and getting a touch of knock here and there on the cel flash, so my timing might be a touch high as well. Im hitting similar boost, spike to 21-22 then come down to 20 and taper down to about 18 at 7k.

The cosi's are just not happy with 91 octane, once you put in 100 they open up a TON.