Hey guys, I was curious if the Octane reading in evoscan is accurate.

I was logging this morning on the way in, and octane was 100 all the way down the log....

well i fill up with CA 91 pisstane BUT i am running a meth kit ( still not %100 on my pump running all the time) . but it just seemed to perfect to say 100 all the way down.

Then again im not extremely educated on it either way.

gurus? any words?

 

That is not your octane level. It actually tells you whether it will switch between the low and high octane maps. Normally, it should always be at 100, which means it only uses the high octane timing/fuel maps. However, if you get repeated knock, it can drop below 100. If it does, then it will start to use the low octane fuel/timing maps. Your car is good if it reads 100, but it doesn't mean you're running 100 octane gas.

 

awesome, thanks so much for the help and clarification!

 

SO other question time

doing my WOT log this morning I was cruising in 4th at about 2300, I tip in and get up above 90% throttle.

all is good, random 1 count knock here and there. then right around 4300 rpm the car hicups like it is going into hard limp and she pops. my heart sank with the fear of *you know what* but no codes, power was normal nothing was leaking and i continued to carry on. so im thinking maybe a backfire?

I looked at the log, and at the point of this happening, i was at 48XX rpms at about 22 psi. no knock counts, nothing.

All i have done is my car with the scaled maf for the agp cai, mode 23, and DTC disabled.

any thoughts. Are back fires to that caliber common ? i mean she has the occasional pop here and there, but that was when I was running a full exhaust. I have the stock cat back on.

I can post the log later as its on my laptop

 

I would say it's the fuel pump relay. That's the exact same thing mine did...hard hesitation with a quick pop, and then continued to accelerate. I checked the logs and there wasn't a single thing wrong. I swapped out the fuel pump relay and it pulled as smooth as can be all the way to redline.

 

^^^^ i already swapped out for the new blue one :-/

 

here is my log, notice the sharp drop in boost about half way through the pull

 

Can't look at your log right now, but is it possible that boost error correction was kicking in? Maybe you exceeded your boost target engine load? Or even your boost limit? If it's not a fuel problem, and there isn't knock, then I would suspect boost personally.

 

You likely exceeded the load threshold in the Boost Limits tables for longer tha 1000ms (1 sec). I started going over the thresholds briefly as of late when I turned up the wick to 28 psi on the street so I had to raise mine again to avoid a sudden boost cut. It's probably more likely to happen if you hammer it in 4th at 4500-5000 RPM where the boost will spike the most and the limits tables typically start to taper downwards from where they are at peak torque.

 

did it feel like you hit a brick wall?

if so - then its boost limit as per above.

 

^^^^

yep brick wall and yep i hit boost limit.

so i raised them about 4 points over the load i was hitting in those rpms and got a successful log thanks for the help gentlemen

 

4 or 40?


i make my boost limit about 20 pts higher than what I hit in the log...

that will help with cold weather etc..

 

4...

hmm maybe i will bump it up a little more. i just didnt want to go to high because i dont ultimately want to defeat the purpose entirely

btw, here is the log i did with the limit increased....

gunzo mentioned i may have incorrectly scaled my maf as im hitting to high load cells i guess for the psi im running.

any pointers?

 

I would increase 20 over logged load like tephra suggested. Boost limit is supposed to cover extreme cases. Normally, your boost target engine load will cause the reactive solenoid to lower boost through error correction if you overshoot your target load. Just make sure you BTEL tables are about right, then add 20 above your target loads for your boost limit table.

 

Yeah, it looks like your MAF scaling is a little too high if you compare boost to your load.

What kind of intake are you running and what injectors? If you are running stock injectors, you may be around 10% too high on your MAF scaling by looking at your LTFT cruise and the load figures. What does your LTFT look like for idle?