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Got my car back from paint yesterday to repair the scratch from my tool cart, missed the car the last 3 days!
I had previously painted the silver center console trim black awhile back but it was starting to get tiny chips so last night I wrapped it in CF vinyl.
So I got tired of chasing the timing getting pulled and said screw it and just shimmed the knock sensor with some o-rings. Had mad wheel spin in 2nd gear lol... Now working on bringing my target boost fuel back up. I was throwing so much fuel at the 5500-6500 range to keep timing from getting pulled. Right now is is pretty much flatlined at 10.0 on the ProSport... 12psi.
Brettus, thought you might be interested in the boost transition. True, I don't exit CL until 100% load, but as you can see in the 3rd gear log I hit 100% load right around 3000 RPM, like I think you mentioned you are seeing, and using the CL fuel targets I was able to get my fuel to in the mid-12's by that point. Not sure if that helps you...
So I got tired of chasing the timing getting pulled and said screw it and just shimmed the knock sensor with some o-rings.
Not a good idea... If it was picking up engine noise you may have fixed that, but caused it to over advance at other areas of the map. If it's working right then you just killed your safety margin.
I'd spray more water and see if the problem goes away.
You're probably right. I just got impatient... I admire and respect the work you've done with the knock sesnor subject. I'm not spraying any water... yet... Probably should start.
Harlan, I'm curious about this, what areas do you suspect timing may be over advancing and why?
The reason why I did this is because I've long suspected false readings triggering timing getting pulled. Some runs are perfect with no timing pulled (and no ill effects that I've noticed) and other runs that pull some and still others that pull a lot. I've seen it get pulled on low boost runs and not pulled on high boost runs, and vice-versa. Always seems to be in the 5500-6500 RPM range.
Knock sensor is ~$70. Not exactly cheap but I agree might be worth replacing. Mine is the original that came with the car, over 9 years old at this point.
This I can say for certain: shimming the sensor I get no timing pulled. Just stating for anyone that thinks the system doesn't actually do anything based on the knock sensor...
AFR is not a reliable indication of detonation. I also doubt replacing it will help.
You may just have too much timing on that area of the map, or it may be some sort of engine noise causing false positives. The only way to be sure is to spray water and see if it goes away or run a higher octane and see if it goes away.
I'm with Slash...by the time that knock sensor sees something wrong it's probably too late on a boosted car. no one is running insane amounts of timing anyway. Go forth and make power slash! what timing are you running up top anyway?
looks conservative to me slash. Look at what cells you should be in during those rpm ranges...you're 175load or higher at 5500rpm. I think the sensor is just overly sensitive.
That's what I'd thought as well. I ran this timing up to 17psi and would sometimes get timing pulled, sometimes not. At the time I had the open dump WG but now it's recirc'ed.
But I just looked at Brettus maps in the turbo ignition thread and his last update (tho from 2012 it seems?) is a bit more conservative than mine...
yomom, Could I get a copy of your timing? I've been doing a lot of reaserch and playing around with all the timing maps I can find and Slash's maps are right on the top edge of them all.
This might take some transulating, but I've taken all the rx8 maps I've found. and rx7 maps I can confirm compression ration's on. Then I converted the pressure into absolute pressure based on compression ratio and boost then estimated the load. I've still got a lot to do, but here's what I have. I also have a map that compares the lowest and highest timing from all of the other maps all on one map to see the timing range people are running.
Last edited by logalinipoo; 08-31-2015 at 09:50 AM.
all my maps are on my broken(thanks to my 2yr old) laptop. I've toyed with the idea of taking it in to get it fixed, but I haven't bothered since the car is down in need of a rebuild.
Is there an issue with windows 8 and accesstuner? I suppose I could put it on my wife's laptop and pull the last tune off the AP
I can tell you I've ran as much as 19degrees of timing up top from memory... I was on a 3gal e85 mix at the time. I only dialed it back because I was experiencing the same thing you are. sometimes it would run the timing, sometimes it would pull timing. When it didn't pull timing, the car was noticeably quicker.
I think the timing being pulled could also be a function of AIT measured from the MAF being high...in your logs is there a difference in air temps from when timing was pulled vs. when it wasn't?
I think the timing is too aggressive, but there are a lot of other things that go into it. I also have no doubt you could get more power in the short run with the knock sensor disabled.
Where do you have your IAT sensor? If it's at the MAF that might be part of the problem. Lets say you hit it hard and heat soak your intercooler then with the IC still hot you hit it again. That hot air is not accounted for in timing and minor detonation could result. The knock sensor does its job and keeps the engine safe, but you see the power loss. If you had the IAT after the IC then it would pull the timing instead. This is a good thing. IAT does not cause detonation when it is accounted for in timing.
I'm still discovering things, but what I've seen so far is that low level detonation happens before any noticeable power loss. You can still push timing at this point without instant ill effects and even gain power, but if you go lean or have any other untuned condition things go south fast. Tuning timing for max power has been a great way to destroy engines.
Again the best way to know if it's real or not is to use higher octane or water to prevent knock and see if it goes away.
08-28-2015, 09:38 AM
