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Old 11-28-2011, 04:02 PM   #1
jprice130
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Default Low DAM Values

I've had my AP for about 4 months and regularly run data logs to assess the health of my engine. Historically my DAM values have always been at 1.0. However, recent data logs have been showing DAM values anywhere from 0.36 to 0.88 during WOT runs in 3rd gear.

From reading previous threads here and on Cobb's website, I've learned that low DAM values aren't a good thing, so I'm obviously a bit concerned. I've been running the current map for about 3 months and the car "feels" totally fine.

The one major change with my car is that I had new motor and transmission mounts installed. Is it possible that the stiffer mounts are throwing off the knock sensor or something? Again, my car feels like it's running as good as ever, but I never had these low DAM values until the new mounts were installed. Is there a possible correlation or just a coincidence?
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Old 11-28-2011, 04:30 PM   #2
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Originally Posted by jprice130 View Post
I've had my AP for about 4 months and regularly run data logs to assess the health of my engine. Historically my DAM values have always been at 1.0. However, recent data logs have been showing DAM values anywhere from 0.36 to 0.88 during WOT runs in 3rd gear.

From reading previous threads here and on Cobb's website, I've learned that low DAM values aren't a good thing, so I'm obviously a bit concerned. I've been running the current map for about 3 months and the car "feels" totally fine.

The one major change with my car is that I had new motor and transmission mounts installed. Is it possible that the stiffer mounts are throwing off the knock sensor or something? Again, my car feels like it's running as good as ever, but I never had these low DAM values until the new mounts were installed. Is there a possible correlation or just a coincidence?
Can you post your logs? What are all your mods? This is a 2006 WRX?

Bill
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Old 11-28-2011, 04:39 PM   #3
jprice130
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Originally Posted by Cobb Tuning View Post
Can you post your logs? What are all your mods? This is a 2006 WRX?

Bill
Thanks for the quick reply Bill. I actually have an 18g turbo with supporting mods and a custom tune via a local performance shop. I normally would just go to them with such questions, but it's been hard to catch up with them due to the holidays and I didn't want to wait around on this if there was a potential issue.

I can post my logs if you like, but I figured you probably wouldn't want to mess around with questions related to another shop's tune. Basically, I was just wanting to know if anyone had ever heard of stiffer motor and tranny mounts throwing off the knock sensor and causing the DAM to drop. If that's not a possibility, then I'll probably just keep my car parked until I can catch up with my local shop.
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Old 11-29-2011, 12:09 PM   #4
jprice130
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Hi Bill, here is a recent data log that shows the DAM dropping while at WOT: https://docs.google.com/spreadsheet/...mdYMUJJRGVnWnc

This log was captured right after I reset the ECU and drove around for 10 minutes. I've continued to monitor the DAM since this log and it has remained at 0.44.

I still haven't been able to catch up with my tuner yet, so if you wouldn't mind providing a quick analysis to help me learn what might be good or bad about the data in this log I'd really appreciate it. I need to drive to work, but I also don't want to risk damaging my engine. Thanks in advance for your help.
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Old 11-30-2011, 10:06 AM   #5
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Originally Posted by jprice130 View Post
Hi Bill, here is a recent data log that shows the DAM dropping while at WOT: https://docs.google.com/spreadsheet/...mdYMUJJRGVnWnc

This log was captured right after I reset the ECU and drove around for 10 minutes. I've continued to monitor the DAM since this log and it has remained at 0.44.

I still haven't been able to catch up with my tuner yet, so if you wouldn't mind providing a quick analysis to help me learn what might be good or bad about the data in this log I'd really appreciate it. I need to drive to work, but I also don't want to risk damaging my engine. Thanks in advance for your help.
I haven't personally seen any aftermarket tranny/motor mounts causing false knock, but, at least in theory, it may be possible (especially with a bad install). You may want to go ahead and swap the factory mounts back in to rule it out. Is this the only thing that has changed before the DAM started dropping?

Bill
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Old 11-30-2011, 11:39 AM   #6
jprice130
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Originally Posted by Cobb Tuning View Post
I haven't personally seen any aftermarket tranny/motor mounts causing false knock, but, at least in theory, it may be possible (especially with a bad install). You may want to go ahead and swap the factory mounts back in to rule it out. Is this the only thing that has changed before the DAM started dropping?

Bill
Thanks Bill, the mounts are the only things that have been installed since the DAM started dropping. One thing I will add, is that I do have a transmission bearing that needs to be replaced that's fairly noisy. It's really only noticeable when my car is idling in neutral and the clutch pedal is out. I don't notice the noise once I'm up to 2nd gear and higher, but I guess that could be because the engine and exhaust sounds are covering it up at that point. Could a noisy transmission bearing throw off the knock sensor?
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Old 11-30-2011, 12:06 PM   #7
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Thanks Bill, the mounts are the only things that have been installed since the DAM started dropping. One thing I will add, is that I do have a transmission bearing that needs to be replaced that's fairly noisy. It's really only noticeable when my car is idling in neutral and the clutch pedal is out. I don't notice the noise once I'm up to 2nd gear and higher, but I guess that could be because the engine and exhaust sounds are covering it up at that point. Could a noisy transmission bearing throw off the knock sensor?
Maybe - did the noise start when the DAM started droppping?

Bill
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Old 11-30-2011, 12:14 PM   #8
jprice130
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Maybe - did the noise start when the DAM started droppping?

Bill
You know it's hard to say exactly when it started, because the noisy bearing didn't become real obvious until the new mounts were installed. I think the bearing has been going bad for a while, but the new mounts make it much more obvious due to the increased NVH that they cause.
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Old 11-30-2011, 12:26 PM   #9
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Timing looks too aggressive for 23psi, fuel is lean and the OL/CL thresholds need adjustment. It isn't the mounts. The AVCS curve looks pretty good on the log though.

If you aren't supposed to be running 23psi (I don't know why you would be running that kind of boost without race gas or methanol) then you should check out your boost control system. If you have the ability to adjust it manually, TURN IT DOWN to 19psi and see if that fixes the problem. If it doesn't, get retuned or just ask them to reduce the timing a few degrees.

Last edited by Maxwell Power; 11-30-2011 at 12:32 PM.
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Old 11-30-2011, 01:52 PM   #10
jprice130
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Timing looks too aggressive for 23psi, fuel is lean and the OL/CL thresholds need adjustment. It isn't the mounts. The AVCS curve looks pretty good on the log though.

If you aren't supposed to be running 23psi (I don't know why you would be running that kind of boost without race gas or methanol) then you should check out your boost control system. If you have the ability to adjust it manually, TURN IT DOWN to 19psi and see if that fixes the problem. If it doesn't, get retuned or just ask them to reduce the timing a few degrees.
Thanks so much for offering your insight on this. My car was tuned in July on a 100 degree day and at that time it was maxing out around 22 PSI and the DAM was always 1.0. I rarely saw any knock values during my WOT runs. Is it possible that the cooler weather is contributing to some of the issues I have now? Also, I have an EBCS, so I don't have a way of manually turning the boost down.

I might be getting in over my head here, but would you mind helping me understand what specifically in my log tells you I'm running lean and that my timing is too aggressive? Also, what is your opinion on an ideal boost target for an 18g turbo (Blouch 18g XT to be specific) on a daily driver/autoX car? The initial goal for my turbo install and tune was to put down 320-330 WHP on a Mustang Dyno using 93 octane gas. Was my goal too aggressive for this turbo?

Sorry for all the questions, but I really want to learn all I can about this stuff and I really appreciate getting knowledge and opinions from experts like yourself.
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Old 11-30-2011, 02:51 PM   #11
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Originally Posted by jprice130 View Post
Thanks so much for offering your insight on this. My car was tuned in July on a 100 degree day and at that time it was maxing out around 22 PSI and the DAM was always 1.0. I rarely saw any knock values during my WOT runs. Is it possible that the cooler weather is contributing to some of the issues I have now? Also, I have an EBCS, so I don't have a way of manually turning the boost down.

I might be getting in over my head here, but would you mind helping me understand what specifically in my log tells you I'm running lean and that my timing is too aggressive? Also, what is your opinion on an ideal boost target for an 18g turbo (Blouch 18g XT to be specific) on a daily driver/autoX car? The initial goal for my turbo install and tune was to put down 320-330 WHP on a Mustang Dyno using 93 octane gas. Was my goal too aggressive for this turbo?

Sorry for all the questions, but I really want to learn all I can about this stuff and I really appreciate getting knowledge and opinions from experts like yourself.
If it was a hot day when you got tuned and your timing values are as logged then this is what I can deduce:

1. Dyno was not in an area with great ventilation or fast moving air across the car other than a few fans in front.
2. You probably have a short ram intake. If you have a cold air intake, then #1 is even more so the case.

basically this is what happens:
1. The ecu sees high IAT values and removes timing from the final timing map. Your tuner neglected to notice this and added timing to your base and advance maps to compensate for the large amount of timing that was being removed due to high IAT. He may have even said something about the car not running as much timing as he was asking it to.
2. You take the car and on a hot day, it runs real similar to how it was tuned.
3. Colder weather rolls in and IAT drops which adds quite a bit of timing to your maps giving you the excessive timing I see on the logs.

or

the tune sucks, but I don't want to go there again with someone from Florida! lol


Your log:
1. Front O2 sensor readings fail rich very fast once you get into boost. So the fact that the reading is still reading leaner than 12:1 with over 6psi of boost tells me that the actual AFRs are quite a bit leaner. The lean spot that is apparent is just during spool when your knock event happens. The timing is also very aggressive there.

Under power 15.5* @4100rpm with 22psi is about 5 degrees more than is needed to blow a low compression STi motor. So if you're running a 2.5L WRX motor with D25 heads... it's crazy aggressive.

2. Under full boost the O2 fails rich at 11:1. So that's good. I can't tell what the AFR is there, but 80% injector duty on an 18G-XT with 23psi tells me you're probably running 750cc injectors. If you are running 650cc, then you could still be lean.

330whp on a Mustang is pretty aggressive for that turbo on pump gas. In all though it depends on the calibration of the dyno.

Last edited by Maxwell Power; 11-30-2011 at 03:06 PM.
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Old 11-30-2011, 03:11 PM   #12
jprice130
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Quote:
Originally Posted by Maxwell Power View Post
If it was a hot day when you got tuned and your timing values are as logged then this is what I can deduce:

1. Dyno was not in an area with great ventilation or fast moving air across the car other than a few fans in front.
2. You probably have a short ram intake. If you have a cold air intake, then #1 is even more so the case.

basically this is what happens:
1. The ecu sees high IAT values and removes timing from the final timing map. Your tuner neglected to notice this and added timing to your base and advance maps to compensate for the large amount of timing that was being removed due to high IAT. He may have even said something about the car not running as much timing as he was asking it to.
2. You take the car and on a hot day, it runs real similar to how it was tuned.
3. Colder weather rolls in and IAT drops which adds quite a bit of timing to your maps giving you the excessive timing I see on the logs.

or

the tune sucks.


Your log:
1. Front O2 sensor readings fail rich very fast once you get into boost. So the fact that the reading is still reading leaner than 12:1 with over 6psi of boost tells me that the actual AFRs are quite a bit leaner. The lean spot that is apparent is just during spool when your knock event happens. The timing is also very aggressive there.

Under power 15.5* @4100rpm with 22psi is about 5 degrees more than is needed to blow a low compression STi motor. So if you're running a 2.5L WRX motor with D25 heads... it's crazy aggressive.

2. Under full boost the O2 fails rich at 11:1. So that's good. I can't tell what the AFR is there, but 80% injector duty on an 18G-XT with 23psi tells me you're probably running 750cc injectors. If you are running 650cc, then you could still be lean.

330whp on a Mustang is pretty aggressive for that turbo on pump gas. In all though it depends on the calibration of the dyno.
Wow, I can't thank you enough for taking the time to share all this info with me. This is great! Of course it also, gives me some worry, but it's better than driving around WOT all the time thinking everything is going to be fine.

To provide a little more info that's specific to some things you've mentioned, The Dyno was in a non-climate controlled garage with fans in the front (garage was open behind the car). I'm still on the stock 2.5 motor and heads, so no work there. I have DW 650CC injectors and I'm using the SPT Cold Air Intake.

Thanks so much for your help and I will definitely take things easy until I can catch up with my tuner and discuss some of the things you've mentioned.
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Old 11-30-2011, 07:24 PM   #13
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Wow, I can't thank you enough for taking the time to share all this info with me. This is great! Of course it also, gives me some worry, but it's better than driving around WOT all the time thinking everything is going to be fine.
You're welcome.
Quote:
Originally Posted by jprice130 View Post
To provide a little more info that's specific to some things you've mentioned, The Dyno was in a non-climate controlled garage with fans in the front (garage was open behind the car). I'm still on the stock 2.5 motor and heads, so no work there. I have DW 650CC injectors and I'm using the SPT Cold Air Intake.
I called it on the dyno didn't I?

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Originally Posted by jprice130 View Post
Thanks so much for your help and I will definitely take things easy until I can catch up with my tuner and discuss some of the things you've mentioned.
Just a little advice:
Many tuners HATE hearing "another tuner said...". I don't know who your tuner is and if he gets bent out of shape when hearing that, so approach it with tact.

Start with the facts:
You logged the car and you were getting 15+ degrees at full boost of 23psi. If that doesn't make him jump or say "holy crap, that's a lot of timing" or even worse if he says "yeah, that's not bad."... RUN.

If he is very receptive, then awesome you have found a humble tuner who cares more about the cars he tunes than his ego.

If he doesn't help you out, I can get you a map that would be safer with less boost that you can have some fun with until you do your compression test. Which reminds me, DO A COMPRESSION TEST. Start by pulling the number 4 plug and seeing if it's covered in burnt oil or junk.
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Old 11-30-2011, 10:19 PM   #14
jprice130
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You're welcome.


I called it on the dyno didn't I?



Just a little advice:
Many tuners HATE hearing "another tuner said...". I don't know who your tuner is and if he gets bent out of shape when hearing that, so approach it with tact.

Start with the facts:
You logged the car and you were getting 15+ degrees at full boost of 23psi. If that doesn't make him jump or say "holy crap, that's a lot of timing" or even worse if he says "yeah, that's not bad."... RUN.

If he is very receptive, then awesome you have found a humble tuner who cares more about the cars he tunes than his ego.

If he doesn't help you out, I can get you a map that would be safer with less boost that you can have some fun with until you do your compression test. Which reminds me, DO A COMPRESSION TEST. Start by pulling the number 4 plug and seeing if it's covered in burnt oil or junk.
Thanks again kind sir. I'm honestly blown away by the amount of information you've shared with me off your own good will. I will definitely take your advice when talking to my tuner. Hopefully others will read the support you've given me here and it will spur some extra business for you. Take care!

Last edited by jprice130; 12-13-2011 at 12:27 PM.
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Old 12-01-2011, 08:20 AM   #15
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I had a tuner set me up here in Vegas without adequate ventilation on the dyno. He was from another state and comes in every so often. I live in the desert. So the car was totally fine until I did a road log after I left. The IAT's dropped down to what they would be for parkway driving and I was getting major timing advances with major knock. He had to send me a revised map to lock the IAT table so no more timing could be added. Needless to say he was kinda pissed every time I made a suggestion on the phone to him. It was just too many problems, it got to the point of, ok I can not change the way he thinks or what he wants to do. So its hard to deal with some tuners. In the end I paid for a tune and called it a learning process and also had an engine replaced.
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