Guys,

I finally took the time to play with my tool! Please give me some thoughts on the attached log. This is my first ever logging attempt and it was a 4th gear pull on 91 craptane! Any advice, critiques, diagnosis, and recommendations are much appreciated.

 

Lots of timing being pulled through peak torque (3-5k rpm) -expected w/91 and that boost level but not ideal. 30C temp rise in a single 4th gear pull is a lot. +octane and intercoolers will be a nice kick in the pants.

Nice response from an X-50 in regards to boost threshold -your exhaust + AMS gates are working well.

 

.73 lambda thru out the rpms range from 3300 to redline is really not good... that's like low 10 afrs... back off the boost, in my opinion you dont fuel for anything above 1.1 bar... your hitting over 1.3 at mid 4s...
one way to see if its the octane is to just add 5 gallons of 100 or 104 see of the lambdas go up...
I would not keep driving the car without addressing the issue for too long...

 

Thanks Earl! I was actually hoping for your response. So, what exactly does "pulling timing" mean (or point me to a good resource)? Which figures are showing this? Also, what may be causing my 30C degree temperature rise?

I have been faithfully following all your intercooler threads! On the lookout for a good deal on some GT2RS coolers! Gates are fairly new. Thanks again!

 

Thanks Mark! Another expert I'm glad to be hearing from! What would you expect the lambdas to be? Mid-80's? I will try the octane boost you suggest. Can I back the boost off by simply loosening the wastegates?

 

You bet! Pulling timing refers to the knock sensor sensing some signs of knock/detonation activity and "pulling timing" or reducing it as a way to maintain more stable combustion -not uncommon with the boost level you're running combined with 91 octane. This is shown by the ignition angle column which is inconsistent and fairly low in the 3-5k rpm range. Ideally timing should taper through peak torque and then increase as rpms rise, but not as erratically as your logs indicate. Downsides are potential engine damage (pistons, rings and rod bearings take a beating with detonation) and high EGTs as the spark event occurs laters. Not saying its full-on devastating detonation, but I think you're near the borderline of the protection offered by the knock sensor loop.

As Markski pointed out, the lamdas indicate a lot of fuel is being added in this range as well -something the DME will also do to stabilize combustion in conjuction with reducing timing.

I will post up a plot of my EPL logs at 1.3 bar with 100 octane in a bit so you can see the difference you might expect by adding some race gas.

 

Awesome. I will definitely find some race gas and do another run soon. You guys do have me a bit concerned though!

 

your car as it stands is far from healthy... not blaming any particular part on the car... but you need to find the problem... so adding race gas is a quick look into whats going on.. IDK you set up but ur also running 94% injector duty cycle at peak TQ... the lambdas are way too low and it is due to knock... too much boost low octane poor cooling= a ****tail for some trouble...

 

my car remotely, 4 revisions ... We ended at around .75 - .77 for the most part under full load 3rd gear pulls, 1.1 bar ... Need to run a bit richer on 91 to avoid detonation. You appear to be a tad rich.

Todd's comment to my question below before we started tuning ..

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Maybe with less boost, you could then lean out the fuel a tad ?, obviously your expertise will know best on this.

Maybe .78 max, but usually .76 on 91. We go .85 on ms109 

 

Thanks JS. Here is my log for a 3rd gear pull done shortly after the above 4th gear pull. Looks like the temperature rise is not as significant, but probably due to the pull right before? Lambda still has issues though.

I just found a Sunoco dealer near me, so I will get some high octane stuff soon. Is it advisable to mix with my 91, or run my car almost dry and just go straight 100 (or more)?

 

Looks like you need some love between 3285 - 5200, timing is all over the place in this range. Should be more consistent, slightly rising towards redline.

Send logs to Tony @ EPL, assuming everything with the car is sound, I'm sure he can lean it out a bit down low. Intercoolers would help keep the temps down, you would see better timing, maybe a good idea to do that first if it's in the budget

 

You will probably see notable gains with a 50/50 mix but for troubleshooting purposes, the closer to 100% race gas the more black & white the answer will be. 100 octane (R+M)/2 method is fine.

Here is your timing vs an old log I have. I was running a little more boost on a hotter day but is an example of the trend you would see if you are octane limited and added race gas. Mine isn't perfect by any means but decent and on the conservstive side. A few bobbles in there but the swings aren't as drastic.

Another can o' worms to consider: Last time I checked, Tony is a big fan of water/meth injection with good failsafes like the Aquamist HFS-3 and HFS-6 systems. This would improve both knock resistance and IATs if 24/7 race gas isn't a viable option. Thread for more info: https://www.6speedonline.com/forums/...-complete.html

 

Not to hijack, but what does the "Boost press of sensor" read in? I can't think of any boost values that go to 2300?

 

millibar absolute pressure

 

Meaning its the boost plus atmospheric pressure? (which is like 1 bar?)