AVCS - Intake and Exhaust Timing

[Kodename47]

Originally Posted by KoolBRZ

No matter what I tried to change the base tables to, it always sucked compared to OTS tunes. I don't know the theory behind the changes Shiv made to the base tables, all I know is it works. I finally gave up trying to change the base tables, and concentrated on the intake and exhaust tables. It seems these tables are just about right, except for a slight hesitation off idle. I'd like you to try these tables on your car and see if you can improve on them. They wouldn't work anywhere near as good without using Shiv's base tables, so I've included those as well. The Intake and Exhaust tables are easy to make, just highlight the biggest square and type the number, highlight a square within that one and type a number, and on until you get to the inner-most square. This tune does just about what I'm looking for in a tune. It makes the car seem eager to go faster. My wife compared it to an excitable little dog like a terrier, that just wants to be let off the leash to run as fast as it can.

Why don't you use vgi's tool to see what AVCS angles you're actually getting? Stock the base is a mirror of the safe and normal tables. There's no reason why you wouldn't do that unless you want the AVCS to change as IAM drops. It seems that you don't understand what your AVCS is doing, that would be my priority number 1.

If you actually want to consistently hit the values in the normal and safe then set them as close as possible, otherwise you end up somewhere in the middle.

[ztan]

Originally Posted by Kodename47

Why don't you use vgi's tool to see what AVCS angles you're actually getting? Stock the base is a mirror of the safe and normal tables. There's no reason why you wouldn't do that unless you want the AVCS to change as IAM drops. It seems that you don't understand what your AVCS is doing, that would be my priority number 1.

If you actually want to consistently hit the values in the normal and safe then set them as close as possible, otherwise you end up somewhere in the middle.

I've just done a drive logging FFF89C88 which interpolates (A01G) between base (FFF89C88 = 1.0) and normal/safe tables (FFF89C88=0.0). The value was stuck at 0.0 the whole time - no base AVCS applied.
@KoolBRZ - if you can log individual RAM addresses and can tell me which ROM calID you're running, I can pull the RAM address for you which switches between AVCS tables.

[KoolBRZ]

Originally Posted by Kodename47

Why don't you use vgi's tool to see what AVCS angles you're actually getting? Stock the base is a mirror of the safe and normal tables. There's no reason why you wouldn't do that unless you want the AVCS to change as IAM drops. It seems that you don't understand what your AVCS is doing, that would be my priority number 1.

If you actually want to consistently hit the values in the normal and safe then set them as close as possible, otherwise you end up somewhere in the middle.

Normal and safe are identical, but the base is totally different. It's the same base tables @Shiv@Openflash uses for NA, E85, even for the ESC tunes. I figure if these safe tables are good enough for Shiv to use in NA, E85, and even ESC tunes, they're good enough for me. I'm already at a big disadvantage power-wise driving an AT geared more for economy than power. Why don't you MT folks change to a 3.30 FD and tell me just how well your engine is running now. My tunes simply have to run well enough to accelerate on their own, without having to give it more and more throttle. That's like pushing it down the road. The maps I posted above are simply my favorite ones so far. It doesn't get the best mileage, but I have a lot more fun driving it. I'm more interested in having fun driving my car than finding out how it works, call me selfish.

[Kodename47]

Originally Posted by KoolBRZ

Normal and safe are identical, but the base is totally different. It's the same base tables @Shiv@Openflash uses for NA, E85, even for the ESC tunes. I figure if these safe tables are good enough for Shiv to use in NA, E85, and even ESC tunes, they're good enough for me. I'm already at a big disadvantage power-wise driving an AT geared more for economy than power. Why don't you MT folks change to a 3.30 FD and tell me just how well your engine is running now. My tunes simply have to run well enough to accelerate on their own, without having to give it more and more throttle. That's like pushing it down the road. The maps I posted above are simply my favorite ones so far. It doesn't get the best mileage, but I have a lot more fun driving it. I'm more interested in having fun driving my car than finding out how it works, call me selfish.

If you see @ztan's reply above you'll see the likelihood that the base even has an impact is zero, so it could all be in your head. Without logging the AVCS angles your getting or the RAM addresses in Tactrix you won't know.

Perhaps the base table is used until the AVCS becomes fully active?

[KoolBRZ]

Originally Posted by Kodename47

If you see @ztan's reply above you'll see the likelihood that the base even has an impact is zero, so it could all be in your head. Without logging the AVCS angles your getting or the RAM addresses in Tactrix you won't know.

Perhaps the base table is used until the AVCS becomes fully active?

The other likelihood is that my IAM is affected by knock, just not enough to drop it below 1.0. I need to start logging again with my current tune to determine areas for improvement. I only have an OFT, so I can't log memory addresses.
So, if I understand correctly, the only code that references changing between safe, normal, and base tables, uses IAM as a determining factor. Then IAM is the only thing affecting which table is used. So if I'm being affected by the base table, there must be a problem in my IAM, which is something I can log with OFT.

[ztan]

Originally Posted by KoolBRZ

The other likelihood is that my IAM is affected by knock, just not enough to drop it below 1.0. I need to start logging again with my current tune to determine areas for improvement. I only have an OFT, so I can't log memory addresses.
So, if I understand correctly, the only code that references changing between safe, normal, and base tables, uses IAM as a determining factor. Then IAM is the only thing affecting which table is used. So if I'm being affected by the base table, there must be a problem in my IAM, which is something I can log with OFT.

Off my logs, the RAM switch that interpolates the base AVCS is 0.0 just after flashing, when IAM is 1.0, and when IAM <1.0. I think that base AVCS map is only active in some form of limp home mode. For A01G calibration, I have not seen the base map used yet and my IAM never drops low enough to use the high det map.

Reducing exhaust retard in the low load area does work fantastically well, though. I'm now running between 10 and 20 degrees of exhaust retard which has made for a much more responsive engine. Besides emissions and fuel efficiency, I wonder if they set the AVCS for engine braking to improve part throttle "feel" when lifting - with the exhaust retard reduced, the engine winds up a lot easier but there is not as much throttle lift deceleration.

[shr133]

Think I'm done till spring, she's all tucked in for winter.... We have snow now...
and I'm not running her through the salt....

I think we are all in the ball park and we are just fine tuning the last little bits of power out....

I have to create a rolling test to measure acceleration while I data log to verify that it is faster....

So I'm thinking like a second or third gear roll on 3000 to 7400....

So that about it for awhile....

[D-VO]

Hey guys. I'm hoping someone could explain why this would be happening. Intake AVCS drops substantially when comparing a 3rd gear pull to a 4th gear pull. I can't find any reasoning for this as all AVCS table data is the same.

[KoolBRZ]

You're not logging Engine Load. The Engine Load would be different between 3rd and 4th gear runs. The AVCS parameters are speed and load. How can you log AVCS effects without logging Engine Load? I'm currently getting lively performance with these tables, Who knew -20 degrees AVCS Intake was even possible? It can even go as far as -24 degrees. Late Intake and late Exhaust is unreasonably peppy. It really comes into it's own at zero degrees though. Compression is a bit higher though, so for the time being I'm using DI only for the most part, with PI only in the last few cells at maximum load and max rpms.

[KoolBRZ]

Oh, and another thing. The AVCS tables should start out at their lowest points to zero out the calibration, otherwise they wander. Zero point for Exhaust is 0 degrees, Zero point for Intake is -24 degrees. That way when the engine is started the cams go to their furthest position, calibrate, then adjust to normal parameters from there.

[D-VO]

Originally Posted by KoolBRZ

Oh, and another thing. The AVCS tables should start out at their lowest points to zero out the calibration, otherwise they wander. Zero point for Exhaust is 0 degrees, Zero point for Intake is -24 degrees. That way when the engine is started the cams go to their furthest position, calibrate, then adjust to normal parameters from there.

Engine load is the column between MAF G/S and AFR. Engine load differs very little between my logs unless I've been logging the wrong engine load parameter which I can't see happening.

I assume you mean set those numbers in the base AVCS tables correct? Exhaust results are as intended but intake is not.

My engine is supercharged by the way.

[KoolBRZ]

Originally Posted by D-VO

Engine load is the column between MAF G/S and AFR. Engine load differs very little between my logs unless I've been logging the wrong engine load parameter which I can't see happening.

I assume you mean set those numbers in the base AVCS tables correct? Exhaust results are as intended but intake is not.

My engine is supercharged by the way.

So is mine, just not as much. I have the Phantom electric SC with a max boost of about 5 PSI at ocean level. I see the Engine Load now. The critical difference I see between the two is how quickly the engine speed is changing. Looks like you were accelerating more rapidly in the first one.

I think maybe your results could be because of what I call "Cam wander". When the cams don't calibrate properly at startup, they can give erratic results. You can also see it as different pressures while logging the same runs. Try changing all the Intake tables to -20 degrees at 600 rpms up to .4 load. (In theory it should go to -24, but I haven't tried that yet, so I can't recommend it.) The Exhaust tables could also use a change to 0 degrees at the same speed and loads. Then the Cams start at their end points and can calibrate from there.

PS. Try using 100% DI up to 1.5 Engine Load, above that, no more than 50% PI to prevent lean condition. It got rid of all my bogging after shifting problems, and made the whole car faster.

[Kodename47]

@D-VO the correct answer is that it's likely to be the difference in oil pressures and the OCV. Is the cam difference repeatable? You could try and reset the learning if you like but if it's targeting the values then this isn't a calibration issue.

Don't forget that the cams use oil to adjust, therefore if the changes in cam are happening quickly, like lower gears, then the actual cam values may end up being a little different to those the targeted values.

Setting values in the tables for "calibration" is rubbish. The car does not use the AVCS tables at idle, nor does the AVCS become active immediately on cold start.

[D-VO]

Originally Posted by Kodename47

@D-VO the correct answer is that it's likely to be the difference in oil pressures and the OCV. Is the cam difference repeatable? You could try and reset the learning if you like but if it's targeting the values then this isn't a calibration issue.

Don't forget that the cams use oil to adjust, therefore if the changes in cam are happening quickly, like lower gears, then the actual cam values may end up being a little different to those the targeted values.

Setting values in the tables for "calibration" is rubbish. The car does not use the AVCS tables at idle, nor does the AVCS become active immediately on cold start.

Thanks I caught that too. It seems that re-calibrating the intake AVCS using the base table did help, and I'm trying to find the smoothest path for the AVCS to track so I won't run into an issue where the AVCS isn't following table values in lower gears as you said.

*EDIT* Re-calibration does not help 100%.

Like I said previously, it was really only the intake that I had a problem with, and my exhaust AVCS really doesn't change too much during high load pulls, so oil pressures would explain why intake AVCS isn't following in the lower gears as well. It's looking good so far; I made a few back to back pulls after changing a few of the values to confirm the changes worked and I'll get back to you guys here.