Timing Changes with 3" Radix Pulley

[.justin.]

I just installed a 3" pulley making a bit over 7psi according to my boost gauge and removed 1.5-3* of timing from the the high and low octane spark from 1.08 g/cyl and above, 2400rpms and above. Saw quite a bit of KR (4* peak outside of WOT), so I pulled another 1.5-3* in the same range, and am still seeing KR as well as not having the truck feel any more powerful than the previous pulley making 6psi. My narrow band O2s are still showing rich and my injectors never go above 85% duty cycle.

 

What type of timing should I be running at full boost in this situation, especially in a downshift situation (saw 6*+ in a kickdoown to 2nd briefly for a split second before I let off).

 

Thanks

justin

[MN C5]

Justin,

 

First, it depends on what timing values you started with

 

Second, don't pull timing with your new pulley ADD FUEL till KR subsides

 

You should be able to run 20 +- degrees on prem 93 fuel with the right tune

 

Dennis

[.justin.]

Justin,

 

First, it depends on what timing values you started with

 

Second, don't pull timing with your new pulley ADD FUEL till KR subsides

 

You should be able to run 20 +-  degrees on prem 93 fuel with the right tune

 

Dennis

<{POST_SNAPBACK}>

 

Okay, if that much timing has been run with that amount of boost with no KR then I will definitely look into that direction, as I'm not even close to that. I won't touch the truck or tune until I get my wideband.

What type of target AFR do you think I should be shooting for to get the cooling effect I need at that point?

[wkdivr]

On my 5.3, with a 3.1 pulley, I'm seeing 10 pounds of boost with the cooler weather. My AFR on my Innovate is reading 11.9-12.0. I think that's the range you need to be in. Some people feel comfortable with 12.0-12.3, some a little richer, like mine.

[wkdivr]

Justin,

 

First, it depends on what timing values you started with

 

Second, don't pull timing with your new pulley ADD FUEL till KR subsides

 

You should be able to run 20 +-  degrees on prem 93 fuel with the right tune

 

Dennis

<{POST_SNAPBACK}>

 

 

You're talking about adding fuel thru the pe table, right? Changing the commanded afr, right?

[.justin.]

Justin,

 

First, it depends on what timing values you started with

 

Second, don't pull timing with your new pulley ADD FUEL till KR subsides

 

You should be able to run 20 +-  degrees on prem 93 fuel with the right tune

 

Dennis

<{POST_SNAPBACK}>

 

 

You're talking about adding timing thru the pe table, right? Changing the commanded afr, right?

<{POST_SNAPBACK}>

 

Usually. In my case it will mean using the Autotune (Ben Factor) capability of EFILive with a wideband in order to get my boost VE ranges dialed in better. Right now I have a "best guess" setup with the MAF covering up mistakes.

[MN C5]

What are your MAF readings peaking at?

[.justin.]

What are your MAF readings peaking at?

<{POST_SNAPBACK}>

 

Ah, good point, something I hadn't checked yet, however I'm hitting KR at mid-rpm, 1.08-1.20g/cyl, well below running out of MAF.

 

I've found that the cause of one big peak was my that my truck leaned way out on decel (0.03V NBO2 reading) and didn't come out of that decel quick enough as I accelerated. Instant 8*KR

 

During a 5*KR, saw right at 10K Maf hz, 3200rpms, 0.9V NBO2 readings with timing dropping from 19 to 14*

 

4*KR, 9914 Maf Hz, 3200rpms again, 0.89-0.91V NBO2 reading, timing drop from 16 to 12 (used Bidi controls to reduce timing 3* for remainder of drive home).

 

IATs under 100* for all instances.

 

I really think you may be right on with the fueling though MN C5. I've neglected it since everything was running so well with the previous pulley. I'll be starting my autotuning next week and hopefully resolving all of this.

[deezel]

I agree. Smaller pulley = more air. Add fuel to compensate.

 

Your KR around 3200 rpms also suggests slightly lean. With a blower, you want to see more like 0.92-0.93V on the NBO2s. I note that the stock PE table has a ramp up in AFR between 2400-3600rpms. With a blower, you might need to move that ramp to a lower rpm range (perhaps 1600-2800) to account for the increased airflow of the blower. For the smaller pulley, you would scale the VE and PE tables up in the boosted areas (and blend a little into the non-boosted adjacent cells).

 

Are you going to a SD tune? If so, the PE table stuff won't matter.

 

The KR on downshifts is difficult to diagnose and get rid of. It can be false knock from the blower or rattling exhaust. It could be false knock from the torque converter unlocking/locking or the transmission jarring. It could be burst knock or real knock. For now, worry most about the KR that happens: 1) at low rpm high load (lugging up hills in 4th gear); and 2) in the middle of WOT acceleration runs.

 

Get that wideband and use it. Best way to know if your AFR is right.

 

The tip-in KR after decel might be affected by the DFCO, PE enable, or spark settings. Take a look at some of these and see if anything looks like it might help your situation.

 

good luck

[.justin.]

I agree.  Smaller pulley = more air.  Add fuel to compensate.

 

Your KR around 3200 rpms also suggests slightly lean.  With a blower, you want to see more like 0.92-0.93V on the NBO2s.  I note that the stock PE table has a ramp up in AFR between 2400-3600rpms.  With a blower, you might need to move that ramp to a lower rpm range (perhaps 1600-2800) to account for the increased airflow of the blower.  For the smaller pulley, you would scale the VE and PE tables up in the boosted areas (and blend a little into the non-boosted adjacent cells).

 

Are you going to a SD tune?  If so, the PE table stuff won't matter.

 

The KR on downshifts is difficult to diagnose and get rid of.  It can be false knock from the blower or rattling exhaust.  It could be false knock from the torque converter unlocking/locking or the transmission jarring.  It could be burst knock or real knock.  For now, worry most about the KR that happens: 1) at low rpm high load (lugging up hills in 4th gear); and 2) in the middle of WOT acceleration runs.

 

Get that wideband and use it.  Best way to know if your AFR is right.

 

The tip-in KR after decel might be affected by the DFCO, PE enable, or spark settings.  Take a look at some of these and see if anything looks like it might help your situation.

 

good luck 

<{POST_SNAPBACK}>

 

My PE is where I want it, so my leaning out is a result of the VE being inaccurate or most likely my MAF being fubar (at one point a couple of months back, MAF was causing me to go lean at 20% throttle until I backed off or got in it more )

I tuned it up to the point that I was seeing 920mv, but the truck was running noticably doggish and I brought that AFR back down. All water under the bridge, as the wideband will straighten that all out.

 

I will initially go to a speed density tune with the WB (obviously) but would like to bring the MAF back into play if i can do it and have it operate properly.

 

I'm about 90% positive that the downshift tip-in KR after decel on the downshift was a result of an excessively lean condition, not caused by DFCO, MAF sensor is the likely culprit . DFCO has not been kicking in since I scaled everything down to run the 2 bar sensor in the 1 bar OS (until now I've been too cheap to upgrade to the commercial version of EFI Live)

 

Thanks for the help guys, it's good to hear the advice, as I was getting concerned that I would not see any real benefit from running a smaller pulley.

[MN C5]

I'd go back to the stock VE table before you start with the W/B. I'd also check your fuel situation, pressure and injector sizing.

[.justin.]

I'd go back to the stock VE table before you start with the W/B. I'd also check your fuel situation, pressure and injector sizing.

<{POST_SNAPBACK}>

 

Can't really go back to stock VE with the 2 bar map, and don't want to really. I'll be bumping it up 20-25% to be on the safe side before Autotuning, as well as starting in lower load cells and gradually working into the higher load cells. I'm going to try and upgrade to a custom OS before starting though that way I won't have to do this all again.

 

Injector Fuel Rate was setup by Bryan at 5.1484, from what I can tell it is correct for the stock radix injectors.

 

Pressure is at 48psi at idle and high vaccum, 62-64 at WOT. Sound right?

[MN C5]

Ok, but I'm confused a bit are you using the 2 bar map with a MAF? Sounds interesting, keep me posted as I've never tuned anything that way myself. You don't have the commercial version right? That means you altered your VE table for the effective MAP voltage i.e. 50kpa is now 25kpa right? I'm not sure how the PCM handles the transitions between the 2bar VE and the MAF but I be interested to know.

 

Link with related infohttp://www.hptuners.com/forum/YaBB.pl?boar...;num=1101917527

[.justin.]

Ok, but I'm confused a bit are you using the 2 bar map with a MAF? Sounds interesting, keep me posted as I've never tuned anything that way myself.  You don't have the commercial version right?  That means you altered your VE table for the effective MAP voltage i.e. 50kpa is now 25kpa right? I'm not sure how the PCM handles the transitions between the 2bar VE and the MAF but I be interested to know.

 

Link with related infohttp://www.hptuners.com/forum/YaBB.pl?boar...;num=1101917527

<{POST_SNAPBACK}>

 

I don't think the PCM has a problem with it, as the VE table is used along with the cylinder volume value to calculate g/sec (or some other unit comparable to the MAF). Then when the PCM needs to bounce back and forth between the two, it is no problem. I ran the truck briefly in SD when I first set up the VE table and noticed very little difference when re-enabling the maf. Not until now when I've upped the boost.

 

I'll run this question by Ben Strader, EFI University owner, and see what he says.