VMP Odin (boost issue?)

[Spykexx]

Long term fuel trims over 1.20? What's going on there

Not going to lie and say I know what to look for fueling wise lol. I know enough from previous coyote logging to watch your typical knock etc. But couldn't tell you what to look for fueling wise honestly. But it does look like a LOT of 1.2+

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[engineermike]

Ok, good we have a log now. The throttle is going WOT as soon as the pedal goes down at 3500 rpm, load at WOT is 1.5 to 1.7, timing is a little lazy starting at 11 and building to 17 deg, lambda is .76, cam timing is running where it should.

The WOT load of 1.5 to 1.7 isn't boost, but it's closely related to it. 1.5 is generally around 8-10 psi and 1.7 is getting up to the 12 psi range. This boost curve is exactly what I would expect for a pump gas PD setup.

The timing is causing some loss of performance. Many tuners will start it out with a low borderline timing and let knock advance add it slowly. You start out at 11.5 deg at 3800 rpm and it slowly climbs, which is hurting your midrange torque a bit.

I don't see anything in the log that says the boost is low.

 

[Spykexx]

Ok, good we have a log now. The throttle is going WOT as soon as the pedal goes down at 3500 rpm, load at WOT is 1.5 to 1.7, timing is a little lazy starting at 11 and building to 17 deg, lambda is .76, cam timing is running where it should.

The WOT load of 1.5 to 1.7 isn't boost, but it's closely related to it. 1.5 is generally around 8-10 psi and 1.7 is getting up to the 12 psi range. This boost curve is exactly what I would expect for a pump gas PD setup.

The timing is causing some loss of performance. Many tuners will start it out with a low borderline timing and let knock advance add it slowly. You start out at 11.5 deg at 3800 rpm and it slowly climbs, which is hurting your midrange torque a bit.

I don't see anything in the log that says the boost is low.

One thing I will note, is I changed up my pullies this morning. I had it on the looser pulley position on the boomerang. I couldn't tell old vs new belt material. So cleaned it all off this morning, and moved the pulley down to the tighter tension setting. (So it MAY have been belt slip). When I look at a previous log, the load isn't getting to 1.7, it's getting to 1.55~ during track runs. The log you see is the log AFTER tightening the belt.

So compounding off this, trying to use what you said as reference and looking at a drag strip run, I'll include previous drag run if any want to look. Absolutely would love to continue learning to read logs.
A) the launch looks bad, and is bad (physically). Launching at 4,000 bogs the car so damn bad.
B) looking at load, is it normal on a PD blower then to not see boost till past 3,000 rpm?
C) Is it normal on a PD blower, to have no boost unless WOT? Kind of wild to me how different and...lazy it feels compared to the ZL1 which wants to go and be in boost literally non-stop.

 

[engineermike]

Couple of observations from the drag log just posted:

- Yes, the load appears to be very slow to build in first gear. Throttle is wide open but, for instance, load is only 1.1 at 3500 rpm. I don't know if it's belt slip or perhaps a lazy bypass valve.
- With the manual trans, the knock advance resets to zero for every shift. This means the timing drops all the way back down to 13 deg at the start of the next gear. This is a result of running a low borderline timing and letting knock advance bring the timing up slowly.
- I see peak load in the 1.63 range, which was a little lower than the other log, but not drastic. Were the ambient temps close? Ambient temp can affect load a decent bit.

I don't generally try to get into boost at low rpm but I was just messing with mine and watched my gauge shoot up past 10 psi at 2000 rpm.

 

[Spykexx]

Couple of observations from the drag log just posted:

- Yes, the load appears to be very slow to build in first gear. Throttle is wide open but, for instance, load is only 1.1 at 3500 rpm. I don't know if it's belt slip or perhaps a lazy bypass valve.
- With the manual trans, the knock advance resets to zero for every shift. This means the timing drops all the way back down to 13 deg at the start of the next gear. This is a result of running a low borderline timing and letting knock advance bring the timing up slowly.
- I see peak load in the 1.63 range, which was a little lower than the other log, but not drastic. Were the ambient temps close? Ambient temp can affect load a decent bit.

I don't generally try to get into boost at low rpm but I was just messing with mine and watched my gauge shoot up past 10 psi at 2000 rpm.

1. I do want to do another check of 1st now that I tightened the belt. Working so will need to wait on that for the time being. But 1st gear feels like a dog, so that seems to correlate. There's almost a solid 1.1-1.3 seconds in the first gear build just from launch to getting back to the 3500 range that the launch killed.
2. Is this something that should be brought up? Such as a higher base line to build on? I do see I'm showing a ton of negative knock, so wouldn't be terrible to add more in? (could be wrong here definitely?)
3. Ambient temps were different a bit. The first log (23) was cooler this morning. Probably 15 degrees different? Friday for log 19 was fairly warm, and a few passes made already. Like 75 vs 88 range.

- update from your edit:
I don't generally try to get into boost at low rpm but I was just messing with mine and watched my gauge shoot up past 10 psi at 2000 rpm.
Oh yea, that is NOT happening on mine lol. It legitimately feels like a dog under 3800~ or so. Burnouts? LOL they don't happen. Like I had said earlier this morning. I am able to put 340TW tires and push the car with no wheel spin.

 

[engineermike]

1. I do want to do another check of 1st now that I tightened the belt. Working so will need to wait on that for the time being. But 1st gear feels like a dog, so that seems to correlate. There's almost a solid 1.1-1.3 seconds in the first gear build just from launch to getting back to the 3500 range that the launch killed.

I hope the belt tightening fixes the issue for you.

2. Is this something that should be brought up? Such as a higher base line to build on? I do see I'm showing a ton of negative knock, so wouldn't be terrible to add more in? (could be wrong here definitely?)

Well, that's between you and your tuner. I like to set mine up with borderline only about 2.5 or 3 deg below knock, then limit knock advance to 2 deg. On pump gas and your boost level, that means setting borderline to something like 16 and let knock advance carry it to 18 if it knocks at 19. That would get you about 3 more deg after the shift which is usually 30-50 hp.

3. Ambient temps were different a bit. The first log (23) was cooler this morning. Probably 15 degrees different? Friday for log 19 was fairly warm, and a few passes made already. Like 75 vs 88 range.

That ambient temp difference accounts for about .04 difference in load.

 

[Spykexx]

I hope the belt tightening fixes the issue for you.



Well, that's between you and your tuner. I like to set mine up with borderline only about 2.5 or 3 deg below knock, then limit knock advance to 2 deg. On pump gas and your boost level, that means setting borderline to something like 16 and let knock advance carry it to 18 if it knocks at 19. That would get you about 3 more deg after the shift which is usually 30-50 hp.



That ambient temp difference accounts for about .04 difference in load.

Thanks for all the help! The logging bit helped a shit load, as I was going nuts not having access to it. The load correlation also really helped me!

One thing I'll say after tightening, it definitely didn't fix the low rpm boost issue. It's still not really getting into boost until ~4,000 rpm just a smaller increase to the peak, it still feels like a dog under 4k. I did reach out to VMP to try and see about getting a bypass valve though. Just trying to knock the easier things out. (Unfortunately almost every single performance shop here is for Chevy, so diving deeper into it gets a bit more troublesome)

 

[Spykexx]

@engineermike You know what. I took a look at this morning's log again. And I was wrong. If you look at the SECOND pull on that log, which I forgot I even did, I started lower in the RPM range. 2100 was the hit, versus the first which was like 3200 start (and a weird 40 pedal then 100).

And the boost is ACTUALLY starting in the 2,000's now, where they weren't prior to tightening the belt, and building fairly fast! Where I wasn't hitting 1.4-1.5 until nearly the end of the gear, now it's hitting that in the 3,000's. I can't say absolutely but that is DEFINITELY a better outlook than all of the prior logs that I've looked through. 4 psi at 2500, is much better than the run from Friday!

 

[Spykexx]

Well, good news! The belt legitimately did it. Not sure if it being a new belt was keeping the belt shreds from occurring or what, but changed the tensioner down to it's tightest spot and she's hitting boost in the 2,000s now almost immediately. I do have on occasion where I'll hit it at 2,000 and it just kind of thinks about it, but that was once in about 20 pulls while I was testing. But overall pulls WAY harder than it was.

So on the 3.5 looks like I'm maxing just over 9 lbs of boost, wondering if I should jump to the 3.4 or not.

 

[HKusp]

Well, good news! The belt legitimately did it. Not sure if it being a new belt was keeping the belt shreds from occurring or what, but changed the tensioner down to it's tightest spot and she's hitting boost in the 2,000s now almost immediately. I do have on occasion where I'll hit it at 2,000 and it just kind of thinks about it, but that was once in about 20 pulls while I was testing. But overall pulls WAY harder than it was.

So on the 3.5 looks like I'm maxing just over 9 lbs of boost, wondering if I should jump to the 3.4 or not.

All things being equal, tune-wise, you should be safe on GOOD pump 93 to 11-12psi, as long as there's no knock.

 

[xr4x4ti]

Well, good news! The belt legitimately did it. Not sure if it being a new belt was keeping the belt shreds from occurring or what, but changed the tensioner down to it's tightest spot and she's hitting boost in the 2,000s now almost immediately. I do have on occasion where I'll hit it at 2,000 and it just kind of thinks about it, but that was once in about 20 pulls while I was testing. But overall pulls WAY harder than it was.

So on the 3.5 looks like I'm maxing just over 9 lbs of boost, wondering if I should jump to the 3.4 or not.

I would go to a 3.3, that felt really good with my Odin.

Like you I had about 9-10psi with a 3.5 and dropped down to a 3.3 and hit about 12.

 

[Spykexx]

I would go to a 3.3, that felt really good with my Odin.

Like you I had about 9-10psi with a 3.5 and dropped down to a 3.3 and hit about 12.

Did you have cats going down to 3.3? VMP doesn't recommend it haha

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