Having some knock readings, need advice.

[Joshmath]

I am currently on a stage 2 MTV 300 91 octane map, however my map says it goes to 16.8 tapering down to 14 at redline, redline being 7000 rpm. I just loaded up the Stage 2 16.8 trickling down to 14 LWG to see if I noticed any differences, I tried the ACN map but holy cow, it felt like power had been completely cut from my car, I hated it and switched back immediately.

[Joshmath]

In some threads I have read they were saying that the ACN 91 fuel was rated at 88-89 octane, it's colder up here in alaska and we are a bit more elevated so I thought that should even it out. I wonder how different the LWG map will feel when I drive later.

[Joshmath]

My knock issue was decreased by about 40-45% with the colder plugs, then eliminated by tweeking the fuel map. It was over a year ago, so I don't remember exact cost, but I think it was about $120....my dealer charges $90 an hour. A regular mechanic would likely be less.

Awesome! I am going to look into this for sure!

[Heide264]

In some threads I have read they were saying that the ACN 91 fuel was rated at 88-89 octane, it's colder up here in alaska and we are a bit more elevated so I thought that should even it out. I wonder how different the LWG map will feel when I drive later.

Just for the record... colder air is denser (and hence contains more air molecules). The cold temps can/will actually promote knock due to the higher cylinder pressures - especially if you are over boosting.

I'd just try the LWG map and see how that goes. It'll probably feel much smoother and you won't be over boosting.

[Joshmath]

You are a gentleman and a scholar Heide, always appreciate seeing your feedback on the forums!

[DemonWRX]

The ecu is supposed to be able to compensate for both elevation and temp changes....at least to a degree.

That being said, the LWG should just modify the boost levels mostly (with small tweeks here and there to fuel), which should smooth things out as Heide suggested. Keep us posted.


OH....and don't forget to let the DAM come up before logging

[Joshmath]

right I'll have to run it a bit, I hear the LWG map spools slower, that might make me hate it... so use to how powerful the other map has been feeling! I freaking love the power the normal map was giving me.

[EJ257]

right I'll have to run it a bit, I hear the LWG map spools slower, that might make me hate it... so use to how powerful the other map has been feeling! I freaking love the power the normal map was giving me.

Before switching maps, try a new log from 2K-redline. It could've just been a tip-in issue with pegging the throttle around where boost really starts to kick in.

[Joshmath]

thanks EJ that sounds like a great idea, will do that directly after work.

[Heide264]

The ecu is supposed to be able to compensate for both elevation and temp changes....at least to a degree.

That being said, the LWG should just modify the boost levels mostly (with small tweeks here and there to fuel), which should smooth things out as Heide suggested. Keep us posted.

OH....and don't forget to let the DAM come up before logging

It will. Your biggest variable with temp will probably be boost characteristics (waste gate duty cycle). The ability for the ECU to do that depends on Cobb's tune though. I know I didn't tune those tables as well as I should have. I would be surprised if Cobb didn't make up a pretty decent table there though.

right I'll have to run it a bit, I hear the LWG map spools slower, that might make me hate it... so use to how powerful the other map has been feeling! I freaking love the power the normal map was giving me.

I am not sure what LWG stands for, but I think it is just a lower initial waste gate duty cycle (wgdc) and a few other odds and ends. That doesn't imply your turbo will spool slower - that's mechanically determined for the most part. Your ECU will add in or subtract wgdc as needed based off of a few correction tables (PID controller minus the differential) and some thresholds (RPM, boost error, engine load, etc). Sometimes just lowering (or raising) the base/initial wgdc will prevent your ECU corrections from causing a rough/jerky feeling pull by actually sticking closer to target boost.

I could be all wet on that though - i'm not sure of the details on that LWG map at all.

Before switching maps, try a new log from 2K-redline. It could've just been a tip-in issue with pegging the throttle around where boost really starts to kick in.

If this is the first time it's happened, do this before flashing. Weird things happen.


Also - I'm not a scholar. Just too much free time and a bit too much OCD in me =P

[Joshmath]

Haha I like it, I want it to be a little bit more smooth, it seems to lag every once in a while and I do get rough/jerky pulls. So maybe the LWG (low wastegate I think?) map will help with that we shall see, on my way home in about an hour I will test out the map I am currently running and post. When you guys see the difference you can tell me if you feel like I should investigate the LWG.

[Joshmath]

ALRIGHT GUYS, here it is,
https://docs.google.com/a/alaska.edu...2VGtFZ1E#gid=0

ugh, only 1 ping on fine knock but I think it might have to do with a big bump I went over while I was doing my pull.

[YorkWRX11]

I would go with a etune. Just my .02. You do pulls / logs and get dialed in. Believe it took me 3 revisions I was originally running the Cobb acn91 since I'm in CA. My etune is so much better than the Cobb one. I use Torqued Performance. Few of friends and my cousin are running his maps as well. Eric is awesome and will respond to your email with revisions very promptly. Best $85 I've spent on my car once I got the accessport.

[Heide264]

ALRIGHT GUYS, here it is,
https://docs.google.com/a/alaska.edu...2VGtFZ1E#gid=0

ugh, only 1 ping on fine knock but I think it might have to do with a big bump I went over while I was doing my pull.

I don't have access =(. In the mean time...

If it is fine knock correction it will clear outside of a given load/rpm range. Maybe 2-2.5k rpm and 1.0-1.5 load or something similar. It's remembered and held for a given time - sometimes a long time, sometimes relatively short. It would depend on the tune. Feedback correction is applied instantly and will count down and clear fairly quickly - and does not care about load/rpm range as long as its within the overall limit.

It's easier to think of what each correction would be useful for. An IAM/DAM tick would be used across the entire range - perhaps a bad tank of fuel. FLKC is used in case you have too much timing, too much boost, or too little fuel in your tune in a specific region (that won't clear quickly). FBKC is more for things such as immediate boost spikes, or tip in/throttle stabbing issues.

[EJ257]

ALRIGHT GUYS, here it is,
https://docs.google.com/a/alaska.edu...2VGtFZ1E#gid=0

ugh, only 1 ping on fine knock but I think it might have to do with a big bump I went over while I was doing my pull.

It's asking for an Alaska University login...