Individual Cylinder Trim

[EllowViper]

Just did some ROE/VEC tuning yesterday for the cooler Tampa weather. I'm curious as to the typical trim offsets people are using. Based on my LTFT and plug readings, I was at about +41 ms on # 1,3,5 +10 on 7, and -51 on #9. #2,4,6 at +36 and 8 +12 and 10 - 56. I can get my LTFT to under 1-2% variation at idle...but I'm using the factory 02 in # 3 and #4...so the LTFT is being based on only one cylynder on each bank. Not ideal, but reading the plugs tells the rest of the story. WB at idle is around 13.5-14.9.(in the collector on the left bank) Basically, #7,8,9,10 require significant leaning based on plug readings (sooty) and smoothing out of the engine at idle. This was for around a 80 degree tune. Anyone running this significant of trim on # 9 and # 10?? Also, I'm running a 170 degree t-stat and only one step colder copper core plugs. My fear is that at WOT #9/10 will be way lean due to the trim factor. Should I reduce the trim on 9/10 and live with poorer closed loop operation or keep trimmed as is? I assume individual trim settings also applies in WOT/open loop. I wish there were trim settings for closed loop and open loop. I think under boost, the issues with #9/10 would be eliminated as each cylinder is being force-fed "equally"...JD Help.

 

[grcforce327]

......................

 

[DAMN YANKEE]

Man, hard to read what you have there...

Might I recommend:

1. Start by listing out your modification specifications.
2. I take it your logging, please post some of those specs as well.

Here is my best shot at translating.
-------------------------------------------------------------------------------------------
Just did some ROE/VEC tuning yesterday.
I'm curious as to the typical trim offsets people are using.

Based on my LTFT and plug readings:
+41 ms on # 1,3,5
+10 on 7
-51 on #9.

(#2,4,6 at +36 and 8 +12 and 10 - 56)??????

I can get my LTFT to under 1-2% variation at idle.
(I'm using the factory 02 in # 3 and #4)?????
The LTFT is being based on only one cylynder on each bank. ?????

Not ideal, but reading the plugs tells the rest of the story.

WB at idle is around 13.5-14.9.(in the collector on the left bank)

Basically, #7,8,9,10 require significant leaning based on plug readings (sooty) and smoothing out of the engine at idle.
This was for around a 80 degree tune.
Anyone running this significant of trim on # 9 and # 10??
Also, I'm running a 170 degree t-stat and only one step colder copper core plugs.
My fear is that at WOT #9/10 will be way lean due to the trim factor.
Should I reduce the trim on 9/10 and live with poorer closed loop operation or keep trimmed as is?
I assume individual trim settings also applies in WOT/open loop.
I wish there were trim settings for closed loop and open loop.
I think under boost, the issues with #9/10 would be eliminated as each cylinder is being force-fed "equally"
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[KenH]

The fuel trims are active at both idle and WOT. Like you, I have also wondered if the air/fuel flow through the manifold was the same at idle as at WOT for the same concern that you have - trimming the rear cylinders to correct a too rich condition under closed loop might lead to a too lean condition under boost.

Nadine was in the process of installing individual EGTs on each cylinder and if she did, that would help to answer the question of whether the air/fuel distribution changed between idle and WOT on a Roe setup.

Here are my trims for reference.
-0.05mS on # 1,3,5, 7
-0.28mS on#9

+0.10mS on # 2,4, 6
-0.05mS on # 8
-0.64mS on #10

Your max differential is 0.97mS compared to my 0.74mS. Whether that is significant or not, who knows but I doubt it.

 

[Steve 00RT/10]

5 pounder. One WB in the driver's side collector area. Upgraded VEC 2 to 3. LTFT set to around +3-5% by boosting the base set from 65% to 70% using the EASE tool..........before monkeying with cylinder trim. My plugs are all the same color. I'll check again in the spring, but all is well with 23K miles on the set up the last 2 years. 170 degree t-stat and the colder Bosch plugs from Sean.

I think you may want to set the LTFT by adjusting the base setting first. Move the individual trims back to the way they came from Sean. Set up the LTFT by adjusting the base set, then play with the individual trim based on the plug info. I wonder the same about closed loop / open loop...but my guess would be that having the base set correct for LTFT somewhat negates the potential harmful adjustments on the individual trim (if the base set is too low). I'm no expert, but our car runs pretty darn good and no issues to date. 77K on the odometer.

1,3,5,7 .13
9 -.05
2,4,6 .15
8 .03
10 -.46

IAT set at +13.1 to -11 at temp variation from 35F to 126.1F. I'm pretty much dialed in from low 30s F to 100F......... I was running the above trims for a year before the IAT thing came into play.

I do think the factory O2s should be in the collector area and not a single tube. Our 01 car came with the O2s in 3&4 (the Belanger 'fix' for O2 MILs). I'm going to change this in the spring as I don't believe the readings are representative of all 5 as evidenced by my WB showing too rich at idle. Changing the location may well result in having to get the 96 PCM or possibly some Dan Cragin O2s......if he still sells them.

Steve

 

[ViperTony]

I do think the factory O2s should be in the collector area and not a single tube. Our 01 car came with the O2s in 3&4 (the Belanger 'fix' for O2 MILs). I'm going to change this in the spring as I don't believe the readings are representative of all 5 as evidenced by my WB showing too rich at idle. Changing the location may well result in having to get the 96 PCM or possibly some Dan Cragin O2s......if he still sells them.

Steve

I don't have a SC install (yet, soon hopefully) but I do have Belanger headers and the Vec3. I'm with Steve in that the O2 sensors should be relocated in the collector area instead of the #3/4 primaries. I was running rich after installing the Belangers and the Vec3 helped lean out the AFR but the AFR still wasn't where it needed to be. I moved the O2 sensors to the collector area to catch all cylinders on each bank. Viola! My AFR improved and my Vec3 tunes are correcting the AFR much better now. However, I did have to buy DC Performances' quick fire O2 sensors to get rid of the check engine light associated with the 'O2 not warming up fast enough' codes AND getting rid of the idle hang that would occur from time to time. Yes, they still have them.

 

[EllowViper]

Thanks guys. I'm going to add one more **** to my driver side this weekend when I take my side sills off to repaint and relocate the factory 02's to the ****. I'll get the quickfire sensors too since I was setting off the CEL when my sensors were in the 2into 1 pipe earlier. I have the extension cables already. Given my current trim offsets, I was going to change my base fuel % like Steve recommends and start over with the LTFT computations since I am already adding a lot of fuel via individual trim. Other than that, if anyone has pulled EGTs like KenH indicates (Nadine), that would be invaluable info.

 

[KenH]

For reference, my injector offset is set to 74% (which is higher than normal). Like Steve, I set this first at idle for best LTFT and then modified trims from there.

I agree that in theory the stock O2's should work better in the collector area, but on my car, it caused my closed loop to run extremely lean for some reason (17 or 18:1) which was corrected once I moved the sensors back up to the header tubes. It might have been an exhaust leak or something similar that lead to my problems, but I could never diagnose it.

 

[EllowViper]

Ken,
What PSI are you pulling with the 6.5 lb pulley? My 5 lb ROE boosts to 8.5 at WOT...both on the gauge and VEC MAP data log. Just wondering if I really have a 5 lb pulley!!

 

[DAMN YANKEE]

Here is a quick log of a 5lb pulley on a good clean log run.

As you can see one can get damn close to 9lbs on a disciplined rig. This is the result of a good blower build out...tight seals and a strong blower. Yours is doing great!

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Now that I understand what you have asked...sorry, I'm just not as fast as the rest of these guys.

1. Definately more your wideband to one of the collectors. You say you are going to buy a ****...get two and weld one in to either collector and cap off one of them. Then you can move your WB as required.
2. Go to Vec3 if possible, update to newest drivers.
3. Use a clean base calibration on a reset PCM (this alone should fix a great deal of your issue) to get your LTFT in line (mine is 67%)
and that should help you out ALOT on the plug issue. Though Im still not sure what your total rig set-up is.
4. If your a 5lb rig, your way over tweaking the individual cylinder trim. #8 and #10 are the usual suspects for individual cylinder trim. What you have listed out (that I get) is too crazy imo. If you have a 5lb rig, I would think that you would not need more than a +.20 tweak on #8 and a .70 tweak on #10. That was a "more than" statement.
5. Steve is wrong, wrong, wrong.....he is an expert.
6. Let us see a log of your WB results....then we can really help you. If you need help posting out your logs...or whatever, just let us know.

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[EllowViper]

Thanks DY,
My WB is in the collector on the driver side. I moved the factory 02s back to the single headerpipe due to setting off the 02 heater circuit malfunction when they were further downstream in the 2-into-1 tube. Right now, I have four bungs in the rt bank and three in the left...just need one more in the left collector if I want to relocate the factory 02 to the bungs on both sides. My A/F is pretty good at 12.2-12.5 up to around 5500 at WOT. I leaned it out a bit from my earlier tune from 11.5-11.9. Working on some timing parameters right now. Fun stuff.
I have the updated VEC-II but not the IAT function.
My base calibration is 63% with theoffsets as discussed. Autolite copper core plug (one step colder than stock). Seems to burn cleaner than the NGK's Sean provided.
I'll try and do some logs in the coming days and dial it in a bit more.

 

[DAMN YANKEE]

Sounds great, sorry about the lambda value (now corrected) just too tired tonight.
Resetting the PCM from scratch and then using the base adjustment will help alot.
I would still like to know what else you have in the rig. Once we worked out the IAT curves they are great for those of us with big temp differences (seasonal). Not sure it would matter much to you.

Now one last thing...imo you should go back to stock Champions unless you are really running very long and hard.

 

[KenH]

Ken,
What PSI are you pulling with the 6.5 lb pulley? My 5 lb ROE boosts to 8.5 at WOT...both on the gauge and VEC MAP data log. Just wondering if I really have a 5 lb pulley!!

I see peaks of 10-11PSI at times. Supposedly the boost is backing up in the intake manifold rather than being what the cylinder sees, but I'm not so sure.

I have tried many of the plugs out there and currently run the NGK Iridiums and I think they give me the smoothest running so far. I also tried the Autolites, NGKs that Sean provides and the ECC10 marine plugs. I would not recommend the stock champions myself. I think a cooler plug is safer, especially on a boosted cast piston car that you like to get into boost with much.

I don't have the AIT temp mod on my VEC2 yet, but I found that when I upgraded my intake to the the PBJ version that mounts the AIT sensor right in the NACA duct air flow, it really reduced the temperature swing problems I was having down to a minimum. I still plan to do the AIT upgrade this winter.

--- Ken

 

[EllowViper]

Thanks Ken. I'm almost finished fabrication my fiberglass version of the PBJ intake; so that will be going on in a week or so. When I was doing some ODB-II data logging, my IAT temps climbed to 120 or so sitting at idle in 75 degree weather (as I was tuning with my laptop sitting in the car). If I recall, it dropped to around 95 or so under accelleration. I had to send back my "borrowed" ODB-II software so I don't have anything right now. Maybe Santa will come through!!

 

[Steve 00RT/10]

I don't have the AIT temp mod on my VEC2 yet, but I found that when I upgraded my intake to the the PBJ version that mounts the AIT sensor right in the NACA duct air flow, it really reduced the temperature swing problems I was having down to a minimum. I still plan to do the AIT upgrade this winter.

--- Ken

My trusty Vipair shows the IAT, as sensed in the stock location, to be 20-30 degrees cooler than the stock airbox set up in the 01 car. This goes for idling as well as hard log runs.

If anyone has a Vipair they wish to part with.....I'd be happy to take it off their hands for a 'modest' sum. I'd like to put it on the 01 car and see if the numbers go down. That would pretty much verify whether it works or not. I have no clue how that temp differential translates to power. I do know that all engines like cooler air and will run a little stronger if they get it. The PBJ box looks very nice, but I don't run K&N type open filters.

Steve

 

[Purdue_Boiler_Viper]

A question for you guys. I just got Belanger headers with bungs in each collector and two WB sensors. I'm about to start my install. My factory O2 sensors are in the stock locations. It appears you guys are moving the stock O2s. Why and where?

Thanks.

 

[ViperTony]

A question for you guys. I just got Belanger headers with bungs in each collector and two WB sensors. I'm about to start my install. My factory O2 sensors are in the stock locations. It appears you guys are moving the stock O2s. Why and where?

Thanks.

I'll try to do this justice...The stock headers located the O2 sensor so that all 5 cylinders were being measured on each bank. The Belanger headers locates the O2 sensor in the #3, #4 primary tubes. This allows AFR to be read from only one cylinder as opposed to reading the entire bank. There's been debate on whether this is good or bad. The bad being that an entire bank can be made too rich or too lean if the #3 cylinder is running rich or lean. But consensus seems to be that allowing the AFR to be adjusted based on a single cylinder is not optimal.

I've had two sets of headers installed prior to my Belangers: Stock and Borla stepped. Both mounted the O2 sensor in a location that read all 5 cylinders. I never had an issue with AFR with those headers. As soon as I installed Belangers, my AFR got rich and I was unable to correct it fully with my Vec3. We checked a number of things. I also replaced my stock O2 sensors with replacement OEM thinking they could've gone bad as I've installed/removed/dropped them a number of times. Eventually, I came to the conclusion that the Belanger O2 **** location wasn't working for me especially when I began experiencing idle hang.

I installed O2 bungs in the collector area and moved my O2 sensors there. AFR was back to normal and my Vec3 tuning was very affective again. I may be the oddity whereby one cylinder was throwing off the entire bank but this doesn't seem to happen to everyone, its rare. Lou Belanger now builds his headers with O2 bungs in the primaries and collector area and leaves the choice up to you.

After I moved my O2 sensors to the collectors, I threw codes. The stock O2 sensors don't heat up quickly enough in the collector area. My PCM sensed this and after about 5-6 starts the codes would be thrown, I would reset them and cycle continued. I researched some old threads suggesting drilling larger holes in the stock sensors. No luck. I purchased DC Performance quick fire sensors, with the correct length wiring, and my codes are gone. These sensors heat up faster and have a faster sampling/response rate.

They also got rid of another problem: idle hang. At idle, the engine RPM would hang a for a short time before settling down. There's a great thread explaining the concept of idle hang being equated to the O2 sensor location being too far away but I can't find it. I seemed to have hit all of these issues with my Belanger installation but the DC Performance O2's solved these specific problems for me. What helped me diagnose the AFR issue was my wideband sensor and Vec3 unit. Spark plug readings also indicated a rich condition but the Vec3 logging helped compare before/after results and correct the issue before it became a real problem.

 

[Steve 00RT/10]

Leave the stock 02s in the factory location--collector area. That is the best place. Moving to a single tube is not sensing the other 4 tubes at all. Problem is that depending on the year of your car, you may set a O2 heater code MIL. Most 2000-02 cars will set this light with Belanger headers. Prior years don't set the light as readily, but I know of a 98 and a 99 that set one a couple times. Dan Cragin sells quick fire O2s to stop the light.

Your WBs will need another hole cut in the collector area. I put mine in the side looking rearward.

Steve

 

[Irid]

I know the race teams I used to work with would always run logs on every cylinder. There's power and safety on the table when they are dead nuts. Someone has to have done this with a stock + blower setup - I wish results were posted as it would be a great place to start. Sean obviously has refined his "as shipped" trims over the years. I would certainly be interested in seeing a pull done with all 10 logging at once though (like with the Innovative kit or somethign) with the final trims, just for giggles.

Someone has to have a set of stock headers mocked up with bungs on each port. Raise your hand ;-)