JB4 Logging, stacking and Map 6 Discussion

[Thegoat]

The freezing temperatures and cold IAT is not causing knock. It's causing the computer to think more about the possibility of knock and it then makes timing corrections. The computer is always using a torque targeting and will try to decide what it thinks is best for the air quality its reading. It will compare that to what it is reading post combustion and try to be a nanny for you. The e85 blended in will help the post combustion readings, so it will then allow you to run more boost without it trying to correct things.

so E85 will help regardless of temps? and the temps have nothing to do with my timing issue?

 

[Thegoat]

im alittle confused by this because im getting timing pull in extreme cold. when it warms up to 40 or so its better. what George said a few posts back about cold air having more o2 which can cause pre ignition. Your saying my car is trying to correct the issue before it gets out of hand?

 

[0bLiViOuS]

Yes, I think that's exactly what they're saying. George also mentioned it'll pull timing to help with torque targeting as well.

 

[Diggs24]

Here is thegoats log:

http://www.golfmk7.com/forums/showthread.php?p=417340#post417340

Frankly, I don't see an issue here. Timing advances fine. Trims are fine. AFR looks fine. He just has 2 cylinders showing knock retard, and according to George unless those go above 3 then it's just part of timing adaptation.

http://www.golfmk7.com/forums/showpost.php?p=418536&postcount=1395

His timing is advancing nicely between 40-60 mark even with "KR" in cylinder 1, indicating to me there is nothing wrong. I don't know that running some E85 will make that KR disappear either, didn't for me.

I say go ahead with map1 thegoat. You will always probably have some KR showing. Just my $0.02 uneducated cents.

 

[0bLiViOuS]

I agree, looks good. More than a set number, what I have been focusing more attention on is the timing advance, boost and throttle/pedal values. If those seem to dip suddenly then it's "real" retard, but if they're holding steady and/or increasing then no need to worry.

I definitely was in the "no retard at all" bandwagon originally, but seeing 100s of logs now from all tuners, there definitely is a lot of "phantom" pull which can be all sorts of things. You'll feel real pull and once you feel the hesitation, you know exactly what I mean. Sure indication seems to be the ECU closing throttle and as a result boost and timing dropping. I think the smooth progression of timing advance is an easy way to check it out. I'll see if I can find a log in the thread as an example of what I mean.

 

[Thegoat]

The hesitation i feel when timing is pulled kinda bugs me. If i can get it to not pull timing or make timing pull as small as possible then thats ny goal. Thanks all for your input

 

[Diggs24]

The hesitation i feel when timing is pulled kinda bugs me. If i can get it to not pull timing or make timing pull as small as possible then thats ny goal. Thanks all for your input

Are you feeling something? Because your log looks fine. If there is wheelspin that will certainly make it feel like it's holding back, but I can't see it in that log. IGN1 (timing) being at 0 up until 4krpm is normal. Mine doesn't start advancing until nearly 4800rpm. The fact that it is over 10 before you even hit 6k rpms is great, that means you can easily add more boost up top.

Have you thought about ditching the DV+? Stock DV is fine. Maybe that is your issue.

 

[Thegoat]

Yea it hesitates, almost feels like a misfire. I have wondered if the dv+ is the cause. Sometimes i think it makes the car over boost which causes some problems then the car has to adjust and pick itself up

 

[Thegoat]

Anyone else have the DV+ and run across some weird hesitations or over boosting?

 

[TwinDad]

Opening a can of worms. Lol

 

[greggles]

Easiest solution, put the stock DV back on, see if it resolves itself. Easy peasy.

 

[Thegoat]

Alright i will have to switch back to stock dv and see how it works out.

 

[rscott4563]

So even in sub freezing temps when the temp outside os below 32F and iat is below 32F or close to it, running E85 still works well in correcting timing even if it lowers the temps more? Knowing that too cold of air entering the engine causes some timing issues.

Id like to run E85 mix and meth at some point and want to know if anyone has timing issues using both or either in the below freezing temps we get in the north east usa

Well if the issue that has been mentioned relating to very cold IATs (denser air higher oxygen content) is in fact detonation then a higher octane fuel would help to prevent this occurring wouldn't it? In fact couldn't a very very cold ambient air temp coupled with an E85 blend could be the perfect combination?


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[rscott4563]

More oxygen content makes it more prone to pre ignite. Also cars at higher altitude can handle more timing/boost based on the same principle.

I always thought pre-ignition was related to hot spots in the combustion chamber rather than oxygen content (AFR). Wouldn't this be detonation?

Also is it possible what is being seen with very cold ambients (and therefore IATs) is that there is over boost (or over leaning out of the AFR) effectively on cars running additive boost as the oxygen content is higher and therefore boost doesn't need to be as high but with additive the ecu is being overridden by the JB4 with a fixed value of additional boost and it's leaning out (kinda like what happens in very hot weather where the ecu is upping boost to combat the lower air density and then there JB4 in additive mode adds a fixed additional amount of boost causing an over boost to occur)?

Or am I just rambling and barking up there wrong tree?


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[0bLiViOuS]

Yes, typically that's what causes pre-ignition, but those aren't the only causes.

I think you're rambling on the other parts haha. I've seen tunes exhibit this when hitting their AFR too (high 11s). The ECU will pull back boost like you said (and if your additive based on JB4 then it'll pull back too). In a nutshell it doesn't seem to be caused by a lean mixture. Look around on the internet and some people might say that, but a properly designed load based ECU can compensate just fine. I know in evoflash there is actually a timing based table for the cold.. too cold or too hot and it retards. I think the same principle is being used here.