Something weird I noticed while data logging

Contour Enthusiasts Group Archives

So I did a lot of datalogging on the dyno today and noticed something interesting. I was doing this with my Xcal2 so that I can get my tunes finalized. Brenspeed gave me 3 conservative tunes first, then with my datalogging they are going to get it nailed down. The most agressive of the 3 tunes added almost 5 degrees of timing. I dont how much the other tunes added, but they werent as much.

Anyway, I started with the most agressive one because that was the one that was on my car when I got there. Everything looked OK, but I switched to the middle tune. Then the dyno operator noticed some choppiness in the powerband and said the knock sensor might be acting up. I decided to start logging the knock sensor advance, and noticed it was pulling up to 3 degrees in the middle of the powerband.

I then switched back to the more extreme tune, and the knock sensor didnt pull anything.

This doesnt make sense to me. Adding a little timing made the knock sensor retard 3* but adding more timing it didnt retard at all. Wouldnt you expect it to retard more?

Me confused

Im off to work, but if you need more info just ask. I can send my excel files to anyone that wants to take a look at what Im talking about.

On a side note my TQ curve is flat as hell

EDIT: My bad. The more aggressive tune retarded timing as well, just not as long or as frequently. Makes a bit more sense I guess.

Maybe the knock sensor is disable in the most aggressive tune?

We want base #'s!

Mark

could also be that with the bit more aggressive tune / timing, they may have added a bit more fuel to compensate for knock.

Just a thought.

Originally posted by Y2KSVT:
We want base #'s!

Mark

Should have them from SZ....i too wonder what kind of numbers the x-cal put out.

Well the numbers are kind of sad, actually. I was on a Dyno Dynamics dyno, which reads incredibly low. The shop that owns it calls it the heart breaker. However, that dyno brand is amazing in what you can do on it and with it. I didnt go in there today to get numbers, I was there for data collection.

FWIW, last time I dyno'd on the Dyno Dynamics I pulled 161whp. 2 months later (0 changes to the car), I pulled 175whp on a Dyno Jet.

Today I dyno'd 163whp. It shows me being fairly lean, same as the first time I pulled up here with no tuning. In Ft. Wayne I was really fat with no tuning. Now Im not at all rich, pretty much at 14-14.5 the whole time. I guess the car isnt compensating as much as it should be for altitude? We have made 0 changes to AFR so far, only timing.

The reason I didnt get on a Dyno Jet is because its a hour drive. This one is 10 min away, plus I know the operator and he gives me discounts on pulls. I was there for an hour and a half and they only lightened my wallet by $56. When I get my "real" tuning done Im going to a Dyno Jet for final numbers so I dont have to wipe away the tears when I leave.

Unfortunately, we have some work ahead of us with my car. And after all of that, Ill be returning to sea level in 5 months and have to do this all over again. Oh well, gotta pay to play!

Originally posted by RTStabler51:
Maybe the knock sensor is disable in the most aggressive tune?

Sounds like a good guess, but here's another:

The aggressive tune just adds a little more fuel than the others and keeps the combustion temps down to resist knock.

Or both possibly. Hell, he aggessive one works just use it.

Quote:

Now Im not at all rich, pretty much at 14-14.5 the whole time

That right there is most of your problem.

Originally posted by Keyser:

Quote:

Now Im not at all rich, pretty much at 14-14.5 the whole time

That right there is most of your problem.

shouldnt he be closer to 12.5?

Originally posted by Keyser:

Quote:

Now Im not at all rich, pretty much at 14-14.5 the whole time

That right there is most of your problem.

And like he said, NO changes were made to AFR. He was wanting to make some changes to timing to see how the car would react at high altitude with some timing thrown at it. Talking with Brent @ Brenspeed, they wanted to be conservative, and have room to play. I'm sure Brent will be sending him some new files for adjusted AFR with possibly some more timing.

But yes, he will be able to move up to the 13.0 range(give or take a couple of tenths) and be safe, and also gain some power.

Sorry to answer that for you Chris, but I don't know if everyone understands your circumstances with altitude change every 6 months

Mark

Ok, I didn't see the fuel ratio thing in his post. 14+ is to high. He can take more timing changes once he brings it down into the 13 range. Probably run a lot of timing on 13.0:1 I'm with Chris, I think he shouldn't be playing with the timing until has the fuel down to a safer range.

Originally posted by warmonger:
... I think he shouldn't be playing with the timing until has the fuel down to a safer range.

That's like russian roulette with your engine. Get that mixture tightened down, then play with the advance so you have far less risk of damage to the engine.

Does this guy also work on wiring lights in his house with the wires live? Just a matter of time...

You are datalogging in 3rd or 4th right??? (4th is best by far)

Datalogging in 1st or 2nd is worthless. The results are too erratic and inconsistent because the rpm is climbing so fast.

Originally posted by DemonSVT:
You are datalogging in 3rd or 4th right??? (4th is best by far)

Datalogging in 1st or 2nd is worthless. The results are too erratic and inconsistent because the rpm is climbing so fast.

******gets out pen,takes note**********...interesting..i've been doing it in third

Best as in you have more time for the fuel deliver system to settle down to a sort of steady state.

If you have a normal or slow car, third is probably fine.
Try datalogging in 2nd gear, that's what my third gear feels like. I have to use 4th for detailed tuning.

Sorry I was in the mountains all weekend.

First, all pulls in 4th, of course.

Second, the graph from this summer at sealevel shoes me at a solid 12:1 AFR. Very consistently so too. Without making any changes except to my location, my AFR shoots up to about 14:1. We havent made any changes to fuel, AFR, anything like that. The AFR also didnt seem to change with the tunes either. It was almost exactly the same each time.

I dont know why its so lean. I feel like it has to be related to altitude. At lower alt. it was so steady at 12:1. Now its steady at 14:1. Like I said, I havent touched a thing besides timing so its got to be something that the car isnt correcting on its own.

BTW, thanks for the help Mark. Feel free to step in!

I'll try to get some of the graphs scanned in tonight.

Here are some graphs:

HP and TQ

HP and AFR (this isnt all the runs, just some of the last ones.)

Now here is the key to the next 3 graphs. Its all the same run with TQ and AFR, but its very detailed so its spread out over 3 pages. I have this for all 3 tunes, but this one is of 2 of the runs with my "stage 3" or most agressive tune (almost +5* timing)

Lastly, here is the graph of my SZ dyno, running much richer!

Seems like the air at high altitude is lesss dense and the computer is putting in less fuel because of it.

Right, but it should still equal out. The PCM *should* be doing it proportionally. Seems like it might be over compensating or something?

Anyone want to see MAF counts?

Originally posted by KingpinSVT:
Sorry I was in the mountains all weekend.

First, all pulls in 4th, of course.

Second, the graph from this summer at sealevel shoes me at a solid 12:1 AFR. Very consistently so too. Without making any changes except to my location, my AFR shoots up to about 14:1. We havent made any changes to fuel, AFR, anything like that. The AFR also didnt seem to change with the tunes either. It was almost exactly the same each time.

I dont know why its so lean. I feel like it has to be related to altitude. At lower alt. it was so steady at 12:1. Now its steady at 14:1. Like I said, I havent touched a thing besides timing so its got to be something that the car isnt correcting on its own.

BTW, thanks for the help Mark. Feel free to step in!

I'll try to get some of the graphs scanned in tonight.

Did you recalibrate the sensor in each location before you climbed to altitude? If you mount the O2 sensor in the exhaust and then drive around without recalibration, things like air density will greatly affect it.
It balances the measured O2 against what it picks up in the atmosphere.
If outside pressure goes up and nothing else changes in the fuel ratio, and there is no calibration, then it will read more rich as the ratio of O2/O2 outside/inside is higher.
IF you lower the pressure then the O2/O2 outside to inside will be lower and read leaner.

OK, I see that they are dyno graphs. Are they the same sensor and did THEY recalibrate.

As you say, there should be automatic compensation because it is a MAF not a map sensor.

What sensor are you talking about? The wideband? I used the wideband that each shop has (I never got one. Well, not yet at least). Im confused about what exactly you are trying to get at.

At first I thought you must have a wideband because you said you measured the A/F both in and out of the mountains.

Then I realized you were talking about two different dynos. Well, the dyno shop may have not had a good or new O2 sensor thats all.
I mean you need to know that it is working right before worrying about changing your tune. If the car isn't pinging then I wonder if it is really at 14:1.

Well that sucks, if I paid all that $$$ to have that data collected and now its worthless then Ill be kinda pissed.

Anyway, Ive never heard pinging before, In my car or another car. Im assuming its fairly loud and noticable? I feel like I know what it *should* sound like, but I havent heard anything out of the ordinary. The dyno operator didnt hear anything either, or Im sure he would have said something as we were doing some diagnostics to try to figure out the knock sensor problem.

I'm surprised the dyno operator didn't shut it down with the AFR being in the 14's in the first place. I know that Dynotech(dyno home of SZ05 & SZ06) will shut it down once it gets anywhere near unsafe levels, or an AFR specified by the owner of the vehicle. It wouldn't hurt(other than your wallet) to hop onto another dyno, or find someone with a wideband that you can borrow.

Mark

Well, looks like Im not going to get my final tuning done until mid-late Jan. then. Ill go to the DynoJet in south Denver and suck it up.

I guess Ill send what I have to Brenspeed anyway, but Brent will probably want to confirm those AFRs before proceeding.