How do I keep my DAM up?

[timber]

Originally Posted by DUB

It works for some. No one knows why it works for some people but not for others.

If you were a bit closer I would let you borrow my cable.

I guess I could ship it to you to log your stuff.. ?

[DUB]

Speaking of Tactrix cables, has anyone looked 'em up recently?

tactrix

WTF? $169. It's cool that they have this new product with a host of features (it logs straight to microSD ) but it sucks that they stopped selling the old, cheaper one.

(unless it's still there somewhere and I'm just missing it)

EDIT: I read up; the old one is no longer available, out of stock and no longer being produced.

[mrevans]

Hey DUB, i've got a tactrix cable you can borrow or buy from me. I never could get it to work with my Mac. Are you in South Lake Tahoe? I am just down the hill in Reno.

Let me know.

[DUB]

So a little update.....

Cliff's Notes: Can nothing more than a hot intake charge cause my Dynamic Advance to fall?

I made my original post from the Reno airport, my DAM had gone down somewhere along the drive.
From South Lake Tahoe to Reno you drop about 1700 ft and it is usually way hotter in Reno.
So on the way back up to Tahoe I was keeping on eye on the DAM and it climbed back up to 10, where it stayed for a few days.
Last week I went out for a little drive on one of my favorite desolate highways, it was a nice cool night. After a little spirited run (I wasn't going too hard for fear that it was detonating) the DAM was back up to 16. yay!
The very next day I headed back down to Reno to buy an Openport cable from mrevans (thanks) and once I got back down into the valley I watched my DAM drop like a stone again. At one point I think it even got down to 1 .
I filled up with known "good" gas and headed back up to Tahoe again. Once I got back into the basin, it was nice and cool. I did two wide open runs and just like that, DAM back to 16.
I have formulated a little theory: Is it possible that my ECU pulls timing simply because of the change in atmospheric pressure as well as a hotter intake charge?

[timber]

Originally Posted by DUB

So a little update.....

Cliff's Notes: Can nothing more than a hot intake charge cause my Dynamic Advance to fall?

I made my original post from the Reno airport, my DAM had gone down somewhere along the drive.
From South Lake Tahoe to Reno you drop about 1700 ft and it is usually way hotter in Reno.
So on the way back up to Tahoe I was keeping on eye on the DAM and it climbed back up to 10, where it stayed for a few days.
Last week I went out for a little drive on one of my favorite desolate highways, it was a nice cool night. After a little spirited run (I wasn't going too hard for fear that it was detonating) the DAM was back up to 16. yay!
The very next day I headed back down to Reno to buy an Openport cable from mrevans (thanks) and once I got back down into the valley I watched my DAM drop like a stone again. At one point I think it even got down to 1 .
I filled up with known "good" gas and headed back up to Tahoe again. Once I got back into the basin, it was nice and cool. I did two wide open runs and just like that, DAM back to 16.
I have formulated a little theory: Is it possible that my ECU pulls timing simply because of the change in atmospheric pressure as well as a hotter intake charge?

That is interesting. Like you, I have a fairly decent elevation/temp change when I drive between St. George and Enterprise. (Enterprise 5500 ft. vs St. George 2200 ft.) I make this drive almost everyday, and have never really noticed much of a difference, but I have never logged. Now I'm curious. Maybe when I get back from vacation, I'll do a little logging, and we can compare notes.

[DUB]

Originally Posted by timber

That is interesting. Like you, I have a fairly decent elevation/temp change when I drive between St. George and Enterprise. (Enterprise 5500 ft. vs St. George 2200 ft.) I make this drive almost everyday, and have never really noticed much of a difference, but I have never logged. Now I'm curious. Maybe when I get back from vacation, I'll do a little logging, and we can compare notes.

Indeed. Now that I have a cable, I should get out and do some proper data logging (I too just got back from vacation ).

I still need to do some research on how to properly log (best parameters/gear/duration of pull/etc).

[timber]

Originally Posted by DUB

Indeed. Now that I have a cable, I should get out and do some proper data logging (I too just got back from vacation ).

I still need to do some research on how to properly log (best parameters/gear/duration of pull/etc).

Let me know what you find out in that regard, because I am unsure also. I'm thinking third gear pull, though, for some reason.

[Donkey]

Yes a hot intake charge can cause the ECU to pull timing by the advance multiplier because it can induce knock.

[timber]

Originally Posted by Donkey

Yes a hot intake charge can cause the ECU to pull timing by the advance multiplier because it can induce knock.

I was hoping you would stop by. What parameters would you suggest for logging, with romraider and no wideband? I'm curious to see what happens with my ride, now.

[Donkey]

Originally Posted by timber

I was hoping you would stop by. What parameters would you suggest for logging, with romraider and no wideband? I'm curious to see what happens with my ride, now.

engine speed
engine load
ignition total timing
knock correction
IAM
learned ignition timing
mass Airflow g/s
manifold Relative pressure
coolant temp
intake air temp

[timber]

Originally Posted by Donkey

engine speed
engine load
ignition total timing
knock correction
IAM
learned ignition timing
mass Airflow g/s
manifold Relative pressure
coolant temp
intake air temp

Thank you very much!

[DUB]

Alright timber, so after we do our multi-elevation logging runs and 'compare notes', who is gonna tell us if our logs look good or not?

[timber]

Originally Posted by DUB

Alright timber, so after we do our multi-elevation logging runs and 'compare notes', who is gonna tell us if our logs look good or not?

I'm hoping we can enlist the help of one of these tuning gurus.

[mycologist]

I've been biting my tongue but it has to be said - have you tried putting your finger in it?



Ok, sounds like a pretty good theory. The ECU pulls boost at higher elevation by the pressure compensation table. It is independent of whatever map you are running. It does this to keep the turbo in the area of the compressor map it wants to use (it has to spin faster to pump the thinner air up to the given boost level). Also, you have greater knock resistance at higher elevation I believe because the air is less dense. I know you can run somewhat lower octane safely at least. So you drive down a long ways and the learned values from high elevation are no longer applicable (because your hitting higher boost and your pushing denser air leaning you out), so the DAM goes down while it trys to sort things out.

[DUB]

Originally Posted by mycologist

Ok, sounds like a pretty good theory. The ECU pulls boost at higher elevation by the pressure compensation table. It is independent of whatever map you are running. It does this to keep the turbo in the area of the compressor map it wants to use (it has to spin faster to pump the thinner air up to the given boost level). Also, you have greater knock resistance at higher elevation I believe because the air is less dense. I know you can run somewhat lower octane safely at least. So you drive down a long ways and the learned values from high elevation are no longer applicable (because your hitting higher boost and your pushing denser air leaning you out), so the DAM goes down while it trys to sort things out.

Nice, thanks. I was thinking along those lines (at least in the ballpark ) I just couldn't put it all together in a thought out coherent manner, as you just did.
I thought elevation probably had something to do with it, I just didn't know what exactly. Also, in the back of my mind I thought maybe elevation had nothing to do with anything since the maniford pressure is just relative to the outside atmospheric pressure anyway.

So here's another little tidbit for you guys: Usually when I'm down in the valley, I see peak boost of ~16.8 (map target is 15.8 +/- .5) which is an over boost of .5 psi. This past weekend I was down in San Fran and I hit 17.4 psi on one pull . Do you think this was because the turbo/waste gate (ecu, really) hadn't yet "learned" that it can slow it's roll and still hit target boost in the dense sea level air? (also, in that particular instance the load was probably huge - 5 dudes in car, going up a slight incline, 3rd gear WOT)

Originally Posted by mycologist

I've been biting my tongue but it has to be said - have you tried putting your finger in it?

I don't get it.