Thoughts?

[lsguy]

Has anyone encountered where you add more air but do not gain any power?

The vehicle was put in OL,
brought the VE error down to the range of 0 to -3.
brought the PE from the baserun of 10's to 11:9 (in several steps e.g. 11:3 11:5 11:9)
brought spark to around 17? on the top end. experience 0.5 - 1? knock.

During all of these changes netted NO POWER DIFFERENCE.
I am perplexed how the prior crap calibration netted the same power with less boost.
Refer to attachment.
thoughts?

2017-12-15 14_44_20-WinPEP 8 Data Center.png

[Jay@HAP]

Where did the spark start out at?

These things like to be rich anyway and don't like a lot of timing.

Leaning out the AFR, isn't going to be where your power increase comes from, it will be from timing.

It's like why a factory car that runs pig rich, doesn't see a big increase in just leaning it out to high 12's/low 13's.

At least this has been my experience.

[lsguy]

Hi,

Thanks for the reply.

For context

This is a 6.1 with a maggie (stock otherwise).

Spark before was 16-17?. with 3 or 4 degrees of knock from 2k-4k.

I reduced in the lower rpm and lowered the upper half 13-15?.
I tried to go back to 17 and there would be 2 degrees of knock...

Is it possible i need to desensitize? could I be hitting a limit (just happened to be there with less boost before?)
Or do these jeeps just suck where I negate the extra boost by dropping 2?. I find that hard to believe.

I've never encountered not making any power with a pulley change.

[* _ *]

are you positive it's pushing in more air [verified psi change?] & not having a belt slip condition?

[lsguy]

are you positive it's pushing in more air [verified psi change?] & not having a belt slip condition?

please refer to the attachment in the original post. the middle window is manifold pressure. run one 4.99psi run two 7.70. The logs show the same kpa difference as well. There is no belt slip. please again refer to how smooth the 7.7psi line is.

[[email protected]]

Post both tunes and logs and we can review. Based on the image you are making more boost so you should be making more power. Where the engine temps the same for the old tune and your tune when you made the pulls?

[* _ *]

Was not able to view the image on mobile device.
It makes no sense to not make more power with more boost, but if the trans is letting up (slipping) or the wheels are spinning (loss in traction) it may produce a false reading as well.

[lsguy]

Post both tunes and logs and we can review. Based on the image you are making more boost so you should be making more power. Where the engine temps the same for the old tune and your tune when you made the pulls?

same engine temps, very similar IATs. Nothing stands out.

Maybe these engines just don't like boost.
Maybe hit a mechanical / exhaust limit?
Maybe I need to desenstize the knock sensors to bring the timing back up to 15-16?? (that would account for the power loss - currently negated by added boost but pulled timing at the moment)

DynoRun2 is the less boost run (with BEFORE.hpt calibration)
T10 is one of a dozen with smaller pulley. (JeepSRT2009_OL_Tuning_Dyno_T11.hpt)

Let me know on your thoughts.
Thanks

[lsguy]

wheels are not slipping. Transmission slipping is an idea. Fluid change had occurred at dealership between the two runs (different days). I myself do not notice slippage on the street though. is there a way to validate this?

[[email protected]]

same engine temps, very similar IATs. Nothing stands out.

Maybe these engines just don't like boost.
Maybe hit a mechanical / exhaust limit?
Maybe I need to desenstize the knock sensors to bring the timing back up to 15-16?? (that would account for the power loss - currently negated by added boost but pulled timing at the moment)

DynoRun2 is the less boost run (with BEFORE.hpt calibration)
T10 is one of a dozen with smaller pulley. (JeepSRT2009_OL_Tuning_Dyno_T11.hpt)

Let me know on your thoughts.
Thanks

First of all these engines love boost - When my SRT Jeep engine was stock we were making 15-17psi on race fuel without issue. Pushed it to 25psi and we couldn't find two of the pistons.
Based on the logs I suggest the following:
1. It appears that you have a belt slip issue. Your MAP starts out above 140kpa and dips into the low 130's and then back up a bit. This could also be an exhaust restriction but I bet it's belt slip.
2. Assuming you are running good fuel you need some more timing. Either determine what is setting the knock sensors off or desensitize them a wee bit to get the timing back.
3. If you are not running quality 93 or higher octane disregard #2 above. You can test if it's real detonation by watching the exhaust or throwing in a splash of race fuel.

[* _ *]

wheels are not slipping. Transmission slipping is an idea. Fluid change had occurred at dealership between the two runs (different days). I myself do not notice slippage on the street though. is there a way to validate this?

rpm values to engine mph should be pretty consistent when compared in parallel.

Monitoring the exhaust back pressure (egt as well) to psi-map readout will help determine if the hard parts are adequate for the system.

[lsguy]

First of all these engines love boost - When my SRT Jeep engine was stock we were making 15-17psi on race fuel without issue. Pushed it to 25psi and we couldn't find two of the pistons.
Based on the logs I suggest the following:
1. It appears that you have a belt slip issue. Your MAP starts out above 140kpa and dips into the low 130's and then back up a bit. This could also be an exhaust restriction but I bet it's belt slip.
2. Assuming you are running good fuel you need some more timing. Either determine what is setting the knock sensors off or desensitize them a wee bit to get the timing back.
3. If you are not running quality 93 or higher octane disregard #2 above. You can test if it's real detonation by watching the exhaust or throwing in a splash of race fuel.

1. there is a ripple yes (indicative of belt slip), fixed in later runs (but unfortunately the other runs had missed logging wideband (so I posted this one) - for all the info. Regardless, this is not the issue. If you refer back to the dyno sheet in posting 1, the boost is reasonably stable and over 7psi. - which should see a power increase.
2. fuel used is 92 Octane gasoline (no ethanol)
3. I could add some higher octane and re-run without changing anything to determine if the knock is fuel related or something else (false knock). - good point.

what specific adjustments can be made to desensitize the knock sensors?

Do you think that the power from the added pressure was negated by timing?

[lsguy]

rpm values to engine mph should be pretty consistent when compared in parallel.

Monitoring the exhaust back pressure (egt as well) to psi-map readout will help determine if the hard parts are adequate for the system.

unable to verify as the wheel height has changed due to tire change. You will see MPH is higher in the latter run with the 30.4" tire height vs 28.5" prior.

[lsguy]

so far nothing looks out of the ordinary in the calibration?
Is there a torque limit being hit? something hidden somewhere? I doubt it because I know of only three ways where tq management can be acted upon. 1. Throttle - but I see the same 86% open. 2. Fuel - Lamda commanded is as expected. 3. spark. dont think so because the commanded spark is as expected.

maybe shit fuel?
This is bizarre.

[* _ *]

unable to verify as the wheel height has changed due to tire change. You will see MPH is higher in the latter run with the 30.4" tire height vs 28.5" prior.

that will not matter.

[[email protected]]

1. there is a ripple yes (indicative of belt slip), fixed in later runs (but unfortunately the other runs had missed logging wideband (so I posted this one) - for all the info. Regardless, this is not the issue. If you refer back to the dyno sheet in posting 1, the boost is reasonably stable and over 7psi. - which should see a power increase.
2. fuel used is 92 Octane gasoline (no ethanol)
3. I could add some higher octane and re-run without changing anything to determine if the knock is fuel related or something else (false knock). - good point.

what specific adjustments can be made to desensitize the knock sensors?

Do you think that the power from the added pressure was negated by timing?

Run some higher octane fuel and see if the KR is gone. If it is you have your answer. If the KR is still there desensitize the knock sensors by raising the voltages slightly (maybe 10% increments) in the area where there is KR. Have someone watch the exhaust ot make sure it's not detonating.