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Old 08-13-2003, 02:00 AM   #1
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Default Autotap Results - Analysis Wanted

I finally broke down and ordered an auto-tap on Sunday night. I had it shipped next day air, so it went out on Monday and was at my house this morning.

I hooked it up and logged a whole bunch of WOT runs, and some partial throttle, all while out driving around for 30 minutes. This was in 80-90 temperatures with very high humidity. I had 2 other people in the car, plus air the condition on and off through out.

My intake temps ranged from 100-115F.

My car is a 2002 SSEi with 3.25 pulley, Thasher CAI, SLP 1.8 Roller Rockers, TOG Headers, and flexpipe. There is no u-bend. I also had half a tank of Sunoco Ultra 94.

The car currently has stock spark plugs.

I had several WOT runs throughout 1st and 2nd with 0 KR - and 9-11 degrees of ignition advance.

I saw a maxium of 4.2 degrees of KR, but this was a spike right in the midde of 2nd on the highway at the begining of a run. I also had a few spikes to 1.7 or 2.3 in begining of runs. The KR would be zero or less than spike for a record or two in the log, than go back down, sometimes all the way to zero.

I actually had my highest spikes under part throttle, although later runs with less, more, or the same throttle produced no KR.

Do you think this might have be false KR? Possibly from dipstick hitting my headers or transmission downshift?

I got a spike when manually shifting the car from 4th, down to 3rd, then 2nd at 60MPH under little to no throttle.

I have read the PCM on the SSEi is much more aggessive on pulling timing, as is the traction control. The TCS will pulling timing even when there is no wheel spin, or its "turned off", if it detects "excessive acceleration".

Does anyone know if this is true, and if TCS would show up as KR on autotap?

Should I get colder plugs?

Would this car be faster with a 3.4 pulley?

Are there any KR mods I should do?
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Old 08-13-2003, 04:51 AM   #2
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Default

I am getting some random numbers as well from the autotap. You can see some of the results in this thread: http://www.bonnevilleclub.com/forum/...pic.php?t=7407 As for the KR I noticed (as shown on the pic in the stated thread) that my KR only showed up after letting off the throttle from full to 0. I'm wondering if this is the PCM sort of engine braking. It would seem consistant with your KR showing up under partial throttle or coming off of WOT.
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Old 08-13-2003, 04:18 PM   #3
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What were your 02'* (B1S1 02 Sensor)? The car may be running lean. I need to get more information before I can tell you why you are getting KR.

1 thing you DEFINATELY need to do is insulate your airbox. You are never going to get rid of your KR with air intake temps of 110. You should easily be able to keep them within 5 degrees of ambient temps.

You also need to put in a 180 degree thermostat (preferably drilled) and 1 or 2 step colder spark plugs. If you do this it should get rid of some KR and make the engine run at a more comfortable temperature if nothing else.

It could possibly have been false KR, but I need more information like I said before. What rpms did the kr start at? What rpms did it stop at? Things like that.

If you get me these things I should be able to tell you what is happening:

A list of every single reading you recorded. I need these readings to include:

Vehicle Speed
Engine RPM'*
Throttle Position Angle
Knock Retard
Barometric Pressure
Manifold Absolute Pressure
Long Term Fuel Trim
Short Term Fuel Trim
B1S1 02 Sensor
Injector Pulse Width
Ignition Timing Advance
Engine Coolant Temperature
Transmission Coolant Temperature
Air Fuel Ratio (optional, but helpful)
Air Intake Temperature
Current Gear (optional, but helpful)

Those are the things that I monitor on the GTP at the track, and i recommend monitoring those things every time you do a log. This information tells you basically everything you need to know about how your car is running. If you give me the readings for those things, I can tell you what needs to be changed on your car to get it running properly.

Logging misfires helps too, although I have never done it before, but it can be helpful if you think it isn't running quite right.
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Old 08-13-2003, 05:12 PM   #4
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Quote:
Originally Posted by dbtk2
What were your 02'* (B1S1 02 Sensor)? The car may be running lean. I need to get more information before I can tell you why you are getting KR.

1 thing you DEFINATELY need to do is insulate your airbox. You are never going to get rid of your KR with air intake temps of 110. You should easily be able to keep them within 5 degrees of ambient temps.

You also need to put in a 180 degree thermostat (preferably drilled) and 1 or 2 step colder spark plugs. If you do this it should get rid of some KR and make the engine run at a more comfortable temperature if nothing else.

It could possibly have been false KR, but I need more information like I said before. What rpms did the kr start at? What rpms did it stop at? Things like that.

If you get me these things I should be able to tell you what is happening:

A list of every single reading you recorded. I need these readings to include:

Vehicle Speed
Engine RPM'*
Throttle Position Angle
Knock Retard
Barometric Pressure
Manifold Absolute Pressure
Long Term Fuel Trim
Short Term Fuel Trim
B1S1 02 Sensor
Injector Pulse Width
Ignition Timing Advance
Engine Coolant Temperature
Transmission Coolant Temperature
Air Fuel Ratio (optional, but helpful)
Air Intake Temperature
Current Gear (optional, but helpful)

Those are the things that I monitor on the GTP at the track, and i recommend monitoring those things every time you do a log. This information tells you basically everything you need to know about how your car is running. If you give me the readings for those things, I can tell you what needs to be changed on your car to get it running properly.

Logging misfires helps too, although I have never done it before, but it can be helpful if you think it isn't running quite right.

The KR spikes occured at various RPM, in 1st, 2nd, and 3rd gear. I was seeing between 48-52 KP of absolute manifold pressure at WOT, 28-30KP barometric pressure. I believe this translates to 10-11PSI of boost.

The KR would sometimes even go down as the RPM, speed, and boost went up. I would also sometimes have KR with a zero knock sensor count.

The vehical speeds were between 20MPH and 90MPH. I can not go WOT under 20 MPH without spinning my tires.

The air-fuel ratio stayed in the 11-12 range at WOT.

Note even at WOT, the throttle position read 99.6%. Is this right?
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Old 08-13-2003, 05:33 PM   #5
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Default More results

I did another bunch of runs today, mostly at the highway. The temps were in high eighties and low nineties.

I saw similar results, athough intake temp was at 120-130 degrees!

I had one run with had ~4.0 degrees of KR at 86MPH and 5333RPM in 2nd gear - 124 degree intake temps. The car spiked to 4.7, right around as I let off throttle and upshifted. I didn't have simolutanious readings for all parameters right here, so not sure of the 4.7 occured at end of full throttle or at let off.

I did another run and only 2KR at 5506RPM in 2nd and 99.6% throttle, and this was with 133 degree intake temps!!! The manifold pressure was 48KP, so 10PSI boost. My air fuel ratio was 11.9.


Why are my intake temps so high? I am going to take a look at the CAI tonight, and see if maybe its hot air coming up around the enclousure?
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Old 08-13-2003, 09:23 PM   #6
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Quote:
The KR would sometimes even go down as the RPM, speed, and boost went up. I would also sometimes have KR with a zero knock sensor count.
If the KR was going down as RPM increased it was mostlikely false KR. Probably generated from the Traction Control, or the sway bar hitting the headers or something like that.

Quote:
The air-fuel ratio stayed in the 11-12 range at WOT.
OK, so the car isn't running extremely rich, or extremely lean, that is good. The thing that is more helpful though is the B1S1 02 Sensor. You can tell much closer how rich or lean you are with that. But between 11 and 12 is about where it should be.

Quote:
Note even at WOT, the throttle position read 99.6%. Is this right?
No, that is not correct as far as I know. Either something is stoping the accelerator from going WOT, or the sensor reads WOT as 99.6% for some reason. You would get more power (obviously not a noticable amount) if you could get it to read 100%. I have seen other SSEi autotaps that read the same thing though, so that may be correct, but it doesn't seem to me like there would be a reason for it.

Quote:
Why are my intake temps so high? I am going to take a look at the CAI tonight, and see if maybe its hot air coming up around the enclousure?
Seeing that reading of 133 degrees for intake air temps is just about right for it being about 90 degrees out. The CAI is not sealed off from the engine bay, so there is nothing to stop the engine heat (in excess of 200 degrees) from going into the airbox along with the outside air. The only good solution to this is to insulate the airbox. By insulating the box and sealing it off from the engine bay you will see air intake temps within 10 degrees (probably within 5 degrees even) of ambient temps. It makes a huge difference. But seeing it is 80-90 degrees where you are when you took that log, that intake air temp is about what it should be with just a regular air box.

Quote:
The car spiked to 4.7, right around as I let off throttle and upshifted. I didn't have simolutanious readings for all parameters right here, so not sure of the 4.7 occured at end of full throttle or at let off.
Did it go to 4.7 and then straight to 0? If it went directly to 0 at the next reading, it was when you let off the gas. Sometimes you will get KR during shifts also, because GM programmed it in to try to save trannies.

Quote:
I had one run with had ~4.0 degrees of KR at 86MPH and 5333RPM in 2nd gear - 124 degree intake temps.
If you get your air intake temps down to 90 or lower (within 5 degrees of ambient air temperature) you will get rid of most of your KR. Seeing that you get kr in every run, I can basically safely assume that it is not false kr. Some of it may be, but not all of it.

Hope this helps.

Shawn
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Old 08-14-2003, 12:29 AM   #7
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This is analysis was really helpful!

So, most of my KR was probably real and due to the the extremely high intake temps, which in turn were do to outside temps and exposed intake.

However, some of this maybe false KR, as indicated by it actually decreasing as boost and rpm increase. The rest may be PCM pulling timing at up shifts.

Overall though, it looks like my car is flowing very well. I am seeing 10-11lbs of boost at WOT and high rpm. Plus even my worse KR, in high temps, with an open intake, is about the same as some people see stock or just with a 3.4 pulley.

Would I be better off with a CAI system like the one from SLP - where it is closed like the stock airbox?

What is the trade-off between the two? Is it more airflow vs colder airflow?

My understanding is the SLP flows enough for a 3.25 pulley, so maybe I should switch over.

Would colder plugs make sense, or will the airbox be enough?

What about the the fact there was KR sometimes with a 0 knock sensor count (i.e. no knock detections)?

I looked at the car tonight and there is a signifcant gap between enclosure for CAI and fender wall, where hot air can get in, plus the enclosure itself is only thin plastic with a metal shield on the bottom.

I also noticed that my engine oil dipstick is right next to one of the collectors on my front header, almost touching it. I couldn't get a good look at tranny dipstick, due to the way the car was parked. I will look at it later.
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Old 08-14-2003, 04:53 AM   #8
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I went back over my logs again.

On the first run (from home to lunch) my intake temps were right around 110 degrees.

On the second run they started at 150 degrees, drop down to 140, and then down into 130s.

I noticed a lot of times their was no knock sensor count at all when the the KR occured. In fact the only time there were knock sensor counts was right as i let up, and upshifted.

Would this be false knock from the upshift, and maybe PCM pulling timing otherwise when there is no knock count?
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Old 08-14-2003, 02:05 PM   #9
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Quote:
So, most of my KR was probably real and due to the the extremely high intake temps, which in turn were do to outside temps and exposed intake.

However, some of this maybe false KR, as indicated by it actually decreasing as boost and rpm increase. The rest may be PCM pulling timing at up shifts.
From what I can tell, yes.

Quote:
Would I be better off with a CAI system like the one from SLP - where it is closed like the stock airbox?
Don't waste your money switching airboxes. Go to Lowes (if you have a Lowes around you somewhere) and buy some insulation, it is basically aluminum foil outside bubble wrap, only not exactly, and it works very good. You can get a big roll (enough to insulate anything you want under the hood) for about $15 IIRC. Insulate your airbox with that, and put the insulation over all of the spaces where underhood heat can get in so it cant. We did this on the GTP and I have never seen AIT more than 6 degrees warmer than outside temps, and they are usually within 2 or 3 degrees. Somebody made a writeup of how to do it, but I can't remember where it is. I will try to find it and post it here if I can.

Quote:
Would colder plugs make sense, or will the airbox be enough?
If the airbox gets rid of all the KR there is no reason to go to colder plugs. But, it seems to me like 1 step colder plugs wouldn't be a bad idea to have anyways. I would also look into a drilled 180 degree thermostat, as that should help keep underhood temps down some.

Quote:
What about the the fact there was KR sometimes with a 0 knock sensor count (i.e. no knock detections)?
Traction Control...as I have said before...It sucks, even when it is off.

Quote:
I noticed a lot of times their was no knock sensor count at all when the the KR occured. In fact the only time there were knock sensor counts was right as i let up, and upshifted.

Would this be false knock from the upshift, and maybe PCM pulling timing otherwise when there is no knock count?
The PCM is programmed to give you KR at the upshifts to help "save" the transmission, but it shouldn't be giving you anything for knock sensor count then. It wouldn't doubt that it is detecting the shift as knock, or maybe when the engine moves because of the shift something hits something and causes false KR, that would be my guess.

I hope I didn't forget anything.

Hope this helps.

Shawn
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Old 08-14-2003, 04:57 PM   #10
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Default Insulation

The insulation idea, is interesting. Would I put this inside the enclosure? Maybe roll a piece and insert in around cone filter?

How does this stay in?
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