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Old 03-17-2012, 02:47 AM   #576
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I trap 115 in the half track mark. Save the watches... Its getting deep in here.
On an MY11 STi with only a TBE?
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Old 03-17-2012, 12:27 PM   #577
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Old 03-17-2012, 02:02 PM   #578
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This is a little unrelated to the discussion above and in general as it's mostly about an STi... but could anyone give a quick explanation as to when angle A is active versus angle B on the intake side of a stock 09 WRX?

They are quite different:
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Old 03-17-2012, 02:49 PM   #579
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Cruise and and accel

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Old 03-17-2012, 04:29 PM   #580
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Get rid of the EGR 'humps' in both intake tables, which you can see in my above posted screenshot as the near flat dinner table and you can run 48 degrees of total ignition timing advance at cruise loads to improve fuel economy. I set my Intel mode maps up to drive like a V6 Toyota, still has heaps of torque and only runs wastegate boost pressure along with being 10x better than the factory Intel mode


Stock 09 Forester XT with just a tune...

They do better with an exhaust to let them breathe
When I was playing with my tune I did find better gas mileage with less overlap but you're saying to take out only the intake avcs and leave the exhaust retard there?
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Old 03-17-2012, 04:32 PM   #581
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The problem with dyno tuning is ramp rates, if the engine wants to accelerate harder than the ramp rate, the loss of airflow inertia results in a loss of torque and then everyone assumes that cam overlap on an STi is not worthwhile.
I don't have any experience with dynos other than road dyno but if this is true then it would also depend what gear you were accelerating in right? In which case what gear would you prefer to tune in? If you tune it in 4th gear then the lower gears will be off. Just curious mainly.
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Old 03-17-2012, 06:41 PM   #582
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This is a little unrelated to the discussion above and in general as it's mostly about an STi... but could anyone give a quick explanation as to when angle A is active versus angle B on the intake side of a stock 09 WRX?
I'm pretty sure there's probably a "map switch ratio" parameter that you can log, which will range from 0 to 1, where 0 is one set of tables and 1 is the other set. I'm not sure which is which, but it shouldn't be hard to figure out just by logging intake AVCS angle and comparing the logged value to the tables.

If you want to tune those tables to suit the conditions that make the map switch ratio parameter shift between them, you should spend some time logging it and figuring out what makes the ratio change.

The other option would be to set those two tables identically and just forget about the switch ratio, at least for now, just to keep things simple. When you get a solid tune that way, then work on optimizing these tables for the different map switch conditions.

If Clark is right about the two tables being for cruise and acceleration, then there aren't going to be and big gains in performance from tuning them separately. If you're in cruise, you're on the left side of the tables (lower loads) and if you're accelerating, you're on the right side of the tables (higher loads). So tune the left side for cruise, and tune the right side for acceleration, and you'll be set.

Not all ROMs actually use that parameter, and the pairs of tables. My LGT has the map switch ratio locked at 1, so there's only one set of tables to tune. And I'm actually happy about that, due to the paragraph above. There are a lot of things in the ROM that I really want to optimize as much as I can, and this isn't one of them.

I figure the dual-table stuff probably only exists for the sake of emissions control, but then again that's my default explanation for anything that I don't understand about the ECU.
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Old 03-17-2012, 11:11 PM   #583
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<SNIP>

Will be quite embarrassing for whoever is wrong...


I am obviously VERY confident... no prize for guessing the red line has 2 degrees more valve overlap from 4800rpm(with around 1psi more manifold boost due to backpressure) but yes, it rev's like a K20A up top. On a dyno, with the correct ramp speed power climbs but if you do not let it build RPM in gear fast enough(ie on the dyno) the dyno causes airflow stall and torque drops off quickly. Once the AFR's are leaned out again, even more power.

PS: That is not my actual tune, just someone who took my advice
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Old 03-17-2012, 11:25 PM   #584
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Who said I run stock cam maps?
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Old 03-17-2012, 11:25 PM   #585
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I don't have any experience with dynos other than road dyno but if this is true then it would also depend what gear you were accelerating in right? In which case what gear would you prefer to tune in? If you tune it in 4th gear then the lower gears will be off. Just curious mainly.
I prefer road/track tuning, I just have unlimited access to two local dynos whenever I need them. I do a road tune(I have a WiFi video camera with suction cup aimed at the exhaust tips, anyone know why?) and then do a 3rd gear log, find 3 ramp rates(ie 2000rpm to 3000rpm, 3000rpm to 5000rpm and then 4000rpm to 7000rpm) and then do a dyno run with all 3 ramp rates. The graphs intersect to give a 'true' dyno graph that drives well on the street.

Find me a turbo car(or cammed car) that accelerates at a set G force through the entire rpm range

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When I was playing with my tune I did find better gas mileage with less overlap but you're saying to take out only the intake avcs and leave the exhaust retard there?
Those intake figures are a good starting point Less Ex retard works well(try 32EX at cruise)
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Old 03-18-2012, 01:49 AM   #586
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Who said I run stock cam maps?
So you run more than 20 degrees cam overlap up top yet on the previous page said cam overlap up top was bad?

Never said you run stock cam maps... anyone else here read that?
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Old 03-18-2012, 01:59 AM   #587
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I'm pretty sure there's probably a "map switch ratio" parameter that you can log, which will range from 0 to 1, where 0 is one set of tables and 1 is the other set. I'm not sure which is which, but it shouldn't be hard to figure out just by logging intake AVCS angle and comparing the logged value to the tables.

If you want to tune those tables to suit the conditions that make the map switch ratio parameter shift between them, you should spend some time logging it and figuring out what makes the ratio change.

The other option would be to set those two tables identically and just forget about the switch ratio, at least for now, just to keep things simple. When you get a solid tune that way, then work on optimizing these tables for the different map switch conditions.

If Clark is right about the two tables being for cruise and acceleration, then there aren't going to be and big gains in performance from tuning them separately. If you're in cruise, you're on the left side of the tables (lower loads) and if you're accelerating, you're on the right side of the tables (higher loads). So tune the left side for cruise, and tune the right side for acceleration, and you'll be set.

Not all ROMs actually use that parameter, and the pairs of tables. My LGT has the map switch ratio locked at 1, so there's only one set of tables to tune. And I'm actually happy about that, due to the paragraph above. There are a lot of things in the ROM that I really want to optimize as much as I can, and this isn't one of them.

I figure the dual-table stuff probably only exists for the sake of emissions control, but then again that's my default explanation for anything that I don't understand about the ECU.
The Cruise and Non-Cruise tables should be tuned separately unless the engine is being built for racing etc. Cruising in 4th/5th/6th gear, it is possible to enter high load regions of the Cruise AVCS table and the Non-Cruise tables in those load ranges are not designed for 'cruise' fuel economy.

Personally, I prefer to rescale the RPM and load ranges to suit specific tasks. Cruise timing and AVCS rarely go over 2g/rev so I have more columns devoted to those columns
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Old 03-28-2012, 12:21 PM   #588
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throttlehappy I tried what you recommended with the timing at around 48 degrees and tapered it in, actually had it a bit high just outside of cruise range so I had to remove some, ended up with another almost 2 degrees from what I had in those areas from my earlier tuning, the cruise timing is now at 46.5, maybe it's a fuel difference or something. I also lowered intake avcs to 5 degrees in cruise areas up to 1.15 load and then tapered it into the rest fairly rapidly, I used 32 degrees of exhaust retard up to 1.3 load and my gas mileage didn't really change. Over the course of a tank my mileage was 20.4 calculated by the dash which equals more like 19.5mpg calculated at the pump. That's a mix of city and highway driving. I simply don't see how you're getting the mileage you say. I've changed my settings again now since it seems to "feel" better the way I have it now. Still wish I had access to a dyno to play with the settings. I think with an accessport and a dyno I could improve it pretty fast.
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Old 04-13-2012, 12:13 PM   #589
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51 degrees of ignition timing here, no knock, less overlap at cruise allows more timing
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Old 04-13-2012, 12:21 PM   #590
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Your going to find out that this approach is a colossal waste of time and fuel Your better off not running the cams this way.

C




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throttlehappy I tried what you recommended with the timing at around 48 degrees and tapered it in, actually had it a bit high just outside of cruise range so I had to remove some, ended up with another almost 2 degrees from what I had in those areas from my earlier tuning, the cruise timing is now at 46.5, maybe it's a fuel difference or something. I also lowered intake avcs to 5 degrees in cruise areas up to 1.15 load and then tapered it into the rest fairly rapidly, I used 32 degrees of exhaust retard up to 1.3 load and my gas mileage didn't really change. Over the course of a tank my mileage was 20.4 calculated by the dash which equals more like 19.5mpg calculated at the pump. That's a mix of city and highway driving. I simply don't see how you're getting the mileage you say. I've changed my settings again now since it seems to "feel" better the way I have it now. Still wish I had access to a dyno to play with the settings. I think with an accessport and a dyno I could improve it pretty fast.
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Old 04-13-2012, 12:31 PM   #591
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I trap 115 in the half track mark. Save the watches... Its getting deep in here.
12.87@108MPH at last Fridays T&T... showroom spec stock standard, no exhaust or intake mods MY11 STi. Took down an e-tuned Stage 3 MY11 WRX with TBE. Definitely not a downhill track either.

The customer did ask for an aggressive tune as she plans for a fully built motor in July. She managed a 13.11 pass on the richer safe tune

Cam overlap up top works and holds torque higher for longer
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Old 04-13-2012, 12:48 PM   #592
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I dont know what you are talking about.

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Old 04-13-2012, 01:27 PM   #593
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Your going to find out that this approach is a colossal waste of time and fuel Your better off not running the cams this way.

C
Well so far thats exactly what I found lol. I didn't try up to 51 degrees of timing either but the testing I did do doesn't seem to be working with the cams that way. It doesn't even make sense to me that it would work but I tried anyway to make sure. Idk how you personally run your cam maps for cruise range but I'm guessing that area is similar to stock based on comments I read from you before. So far playing with it (unfortunately without a dyno) damn things are expensive haha. I found that running near 17 degrees exhaust retard but high intake advance seems to work best for me. I really feel like the exhaust cam timing was just put in for emissions purposes. I've tried tons of different settings and if it is more than 5 degrees from 17 it just loses torque/power. Depending on which way I go it also makes the engine more prone to knock. Maybe with a different set of mods it can be made to work better, Sponaugle seemed to have good results playing with it and you mentioned that his maps were similar to yours on a 30r so thats two respected tuners saying it works well. When I get around to changing to a real turbo we'll see how it works for me.
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Old 04-13-2012, 01:58 PM   #594
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I agree. You can run a few degrees more exhaust side but only past the trq peak. That might help you out a bit but not much. Dont go crazy with the intake cam advance. The stock map is not bad. There are some things I do between the cruise and accel maps. But Your not going to find big power gains here on your 08. When we start changing turbos and engines where my experience comes into play with these maps. I have hundreds of hours of chasis Load dyno experience with tuning those maps and I have come up with some favorites over the years and I stick to them.

Adjusting the advance and retard and moving seperation of cams is what we call Dynamic compression in the industry. Sometimes also called Running compression. This is something that needs to be understood. If you alter the dynamic compression of the motor, Your timing map is likely no longer valid.

Do not over advance your timing off boost. That is one of the biggest mistakes noobs make. Timing is not a volume knob for power and only has one correct settting. Comments like "conservative timing" is a red flag for someone that does not know what they are doing. Its easy to blow a motor and crack a piston "OFF boost" by creating preignition. You get light det during cruise and tip in. Your ring lands and rod bearings suffer.
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Old 04-13-2012, 02:23 PM   #595
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Duplicate.
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Old 04-13-2012, 03:00 PM   #596
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I agree. You can run a few degrees more exhaust side but only past the trq peak. That might help you out a bit but not much. Dont go crazy with the intake cam advance. The stock map is not bad. There are some things I do between the cruise and accel maps. But Your not going to find big power gains here on your 08. When we start changing turbos and engines where my experience comes into play with these maps. I have hundreds of hours of chasis Load dyno experience with tuning those maps and I have come up with some favorites over the years and I stick to them.

Adjusting the advance and retard and moving seperation of cams is what we call Dynamic compression in the industry. Sometimes also called Running compression. This is something that needs to be understood. If you alter the dynamic compression of the motor, Your timing map is likely no longer valid.

Do not over advance your timing off boost. That is one of the biggest mistakes noobs make. Timing is not a volume knob for power and only has one correct settting. Comments like "conservative timing" is a red flag for someone that does not know what they are doing. Its easy to blow a motor and crack a piston "OFF boost" by creating preignition. You get light det during cruise and tip in. Your ring lands and rod bearings suffer.
I understand the dynamic compression idea and also that it affects the timing curve (in some cases dramatically). I get what you're saying that timing isn't a knob for power, but I somewhat disagree that there is only one correct timing. In low load areas this is generally true but in boost areas, many subies are knock limited on timing at ~11:1 afrs on 91 octane. So in this case the "correct timing" would only be attainable with more fuel but you would make more power with the leaner afr and less timing. So in this case conservative timing would just be the term used to describe how far you backed it off from knock to account for changes in running conditions. The stock ecu has settings that are supposed to account for those changes but they don't do a great job, and the further from stock you get the worse it gets. So conservative timing could mean they don't know what they are doing but it also may not. On some setups I can advance timing beyond mbt without knock but on others it's knock limited. I also generally try to do at least a couple pulls in quick succession to see how the car deals with the heat buildup. Many times I can run a set timing for one pull but after 2-3 pulls it knocks at that same timing and fuel even with the iat's being the same or even lower. If that happens I revise the tune a bit to prevent it. In this case the tune I leave them with is slightly "more conservative" meaning that they can beat on it without knock, but makes a bit less power than I could have for one pull. Many tuners just leave it with the higher dyno reading and allow the ecu to pull timing in the event it knocks which I personally disagree with. Thanks for the advice you've offered. I get frustrated with your lack of data sometimes but I do appreciate when you give advice.
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Old 04-13-2012, 03:15 PM   #597
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Cam overlap up top works and holds torque higher for longer
On a bone stock setup? That seems hard to believe knowing what we know about the pressures in the uppipe. Unless there's something else I am not considering in the equation. My VE calculations showed that extending overlap past ~4400 RPMs dropped my VE.

FYI, JDM cams and ADM cams are different that USDM cams. AVCS numbers are always with respect to the resting position of the cam andd the cams themselves have different resting positions, depending on the domestic market. What that means is that the same AVCS maps for a JDM car do something different than on a USDM car. Just wanted to make that clear. The USDM STI cam positions have been published and are well understood:

Intake TDC: 5 degrees of advance
Exhaust TDC: 12 degrees of retard

What are the numbers for ADM and JDM?

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Old 04-13-2012, 03:30 PM   #598
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Do not over advance your timing off boost. That is one of the biggest mistakes noobs make. Timing is not a volume knob for power and only has one correct settting. Comments like "conservative timing" is a red flag for someone that does not know what they are doing. Its easy to blow a motor and crack a piston "OFF boost" by creating preignition. You get light det during cruise and tip in. Your ring lands and rod bearings suffer.
In strictly scientific terms, you are correct. At any given time, there is only 1 ideal timing that will produce best combustion. That being said, there is a range of timing that can be used that will be adequate and will not harm the engine. For example, if 45 degrees is an ideal setting for a given load, RPM, fueling at a particular IAT, 44 will not cause the car to granade nor will 46 cause it to explode. Given the sheer nature of how ECU calculates timing based on interpolation, there is certain amount of error that is built into the system, by design. Most people interpret "conservative timing" term as timing that is slightly lower than what the knock threshold happens to be at a given time. If I know that my car consistently knocks at 45 degrees because timing is too high, some may dial in 43.5 degrees of timing and accept the 1.5 degrees as safety margin. Obviously, going to 30 degrees in this case isn't "safer". Lack of timing has its own dangers too.

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Old 04-13-2012, 03:52 PM   #599
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51 degrees of ignition timing here, no knock, less overlap at cruise allows more timing
I am not sure about that. This is complicated and conventional VVT science states the opposite for low load cruising situations. In cruise, you want lots of overlap to promote internal EGR to cool the combustions cycle and reduce the pumping loses. But, there's a limit to how far you can take that. Too much EGR will destabilize your combustion. It is possible that one might have dialed in too much overlap, registered knock and concluded that the car is running too much timing. By reducing overlap, you might be stabilizing the combustion which allows the car to tolerate more timing now. So, if you're on the EGR stability threshold, the above may hold true. But if you continue to reduce the overlap, you'll find that you will be dropping your timing, as you approach ideal VE. Typically, the closer you get to best VE, the less timing you will need for optimal burn. So, the big question is, would decreasing overlap bring you closer or further away from ideal VE? Depending on that answer, the timing will follow
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Old 04-13-2012, 04:36 PM   #600
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Even at low load and low rpm, there is really only one advancement of timing that is proper for the engine setup as a whole.

Any sway from this will reduce power or effeciency. That range is pretty narrow. Tuners that dont work in an environment that can show this, will suggest otherwise because they do not know better.

If you hold the engine at a low load against the computer controlled LOCK, You can adjust timing up and down to find the proper setting. EGT is required here. Open source is not usable for this application. Cobb or a standalone system is required.

When you speak of timing for low octane, You must make serious compromises here in power. However, Even with this in mind, low octane fuel has only one optimal setting. Under advanced can be very harmfull. Over advanced can be very harmfull.

Without the use of a load dyno that can hold the engine at any rpm/load AND produce a TRQ readout showing you incremental changes, THere is no way to tune the timing map correctly. There are only a few places in the US that I know of that can offer this kind of facility called a Dyno cell. The room must have an incredible fresh air cooling system. Not fans blowing on a radiator. I have been to three.

Most Hacks just add athority to the advance table and let the knock sensors tune the cars. Obviously. This is a short cut and as a result. The tune is not optimal. But to the 99 percent of the hacks out there, They just care what the dyno sheet says and if it says they made power. They are happy. If the tuners idea of tuning a car is to go for 11 to 1, run as much boost as they dare, and then crank the timing up to the edge, They are not a tuner,They are a hack and have alot to learn.

Over and out.. Time for lunch



C



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Originally Posted by kakarot09 View Post
I understand the dynamic compression idea and also that it affects the timing curve (in some cases dramatically). I get what you're saying that timing isn't a knob for power, but I somewhat disagree that there is only one correct timing. In low load areas this is generally true but in boost areas, many subies are knock limited on timing at ~11:1 afrs on 91 octane. So in this case the "correct timing" would only be attainable with more fuel but you would make more power with the leaner afr and less timing. So in this case conservative timing would just be the term used to describe how far you backed it off from knock to account for changes in running conditions. The stock ecu has settings that are supposed to account for those changes but they don't do a great job, and the further from stock you get the worse it gets. So conservative timing could mean they don't know what they are doing but it also may not. On some setups I can advance timing beyond mbt without knock but on others it's knock limited. I also generally try to do at least a couple pulls in quick succession to see how the car deals with the heat buildup. Many times I can run a set timing for one pull but after 2-3 pulls it knocks at that same timing and fuel even with the iat's being the same or even lower. If that happens I revise the tune a bit to prevent it. In this case the tune I leave them with is slightly "more conservative" meaning that they can beat on it without knock, but makes a bit less power than I could have for one pull. Many tuners just leave it with the higher dyno reading and allow the ecu to pull timing in the event it knocks which I personally disagree with. Thanks for the advice you've offered. I get frustrated with your lack of data sometimes but I do appreciate when you give advice.
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