HUGE HP Loss - V Dyno results w/revised Stratified e-Tune

[brbauer2]

I'm befuddled by the results from my pulls today. First 3rd & Second 3rd graphs are from today (7/3), while Log Review 6 & Log Review 3 are from several months back (2/16).

I used the same road - one run northbound, one run southbound
Only environmental difference is ambient temps today (76) vs. then (38).

Changes to the car:

• Stock -> MBRP exhaust
• Stock Spark Plugs -> NGK LTR7IX-11 (1-step colder)
• 15" Winter wheels -> 17" Summer wheels (~3lb/corner heavier)
• Stock FMIC -> Whoosh FMIC

All runs done on 93 fuel using the same revised 93 e-Tune from Stratified.

I don't 'feel' a power loss with my butt dyno, but I did notice 0-60 times were closer to 8 seconds instead of 7.

How can there be nearly a 50hp loss? Should I be worried? Is it just a matter of winter fuel/summer fuel, the temp change, and parts changes? Would I be best off getting another revision?

[MENTION=4300]Alex@Stratified[/MENTION]

**edit**

Here's the logs on DataZap

2-16-17

7-3-17

**edit 2**

Found time after work and some open road so I tested. I have not changed/looked at/fixed anything yet. Just did 3 pulls using the revised Strat Flash Tune, COBB Stage 0, and COBB Stage 2 93 oct.

DataZap
Stratified
Stage 0
Stage 2

 

[LilPartyBox]

That's a significant temp change. Heat is the enemy of power. Winter gas also hurts. Heavier wheels. It all adds up. 50hp loss is on the high side but also keep in mind that vdyno isn't perfect either. I would def get the log review from strat and forget the whole incident and get back to bangin through gears.

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[haste]

Your first two logs don't look the same as the 2nd set. It is hard to make a comparison of the two since all 4 runs aren't consistent.

 

[Fiestarawpower]

Has to do with the weather. that's a big difference going from 36'' to 76''. Also you going from a 15' wheel to a 17' wheel makes a difference too. more rotational mass, equals slower acceleration. Also make sure that your OAR on the accessport is at -1. If its not that can contribute to less power as well.

 

[brbauer2]

OAR almost always sits strong at -1, winter gas was in on the higher HP runs.

Been thinking of going e30 for a while now, just need to budget it in and pull the trigger.

I also noticed that Ignition Correction/Ignition Timing for Cylinder 1-4 was adding the whole pull with 0 knock. That's leading me to believe the tune is running on the conservative side.

 

[Erbarry]

Show AFR and boost to see what's going on there.

 

[brbauer2]

Show AFR and boost to see what's going on there.

Added links to DataZap logs to the bottom of OP.

 

[1azst]

Are you 100% sure the fmic clamps are still tight?

 

[1azst]

You're flowing 21lbs/ min at the top end, with 13° timing. That seems like it should be 200ish whp. Is vdyno definitely set up the same as before?

 

[brbauer2]

Are you 100% sure the fmic clamps are still tight?

Can't be 100% sure, but I have ~7500 miles with the FMIC install and haven't heard or felt a boost leak in that time. The DataZap logs between all runs look to be pretty steady with boost levels as well.

 

[brbauer2]

You're flowing 21lbs/ min at the top end, with 13° timing. That seems like it should be 200ish whp. Is vdyno definitely set up the same as before?

Checked it several times.

 

[Erbarry]

Are you using the same road?

 

[Alex@Stratified]

Had a look at the datalogs are clean. Boost is within expected range, timing is as well with no knock interfering.

The temperatures are not very hot either.

The shapes of the power graphs from your latest runs are what they should be - they are just offset down. This usually indicates an issue in the setup with virtual dyno or a consistent grade incline or some sort of headwind.

Double check that the vehicle data such as the gearing and frontal area are correctly setup.

 

[Alex@Stratified]

Looked closer at the datalogs side by side. The tune in spite of the heat is running very similar boost as well as timing curves which are largely responsible for power output. The early logs were taken near freezing temperatures but the offset in acceleration time between the 2 is more than what temperature would result in.

So one of 2 things are going on here. Either there is a grade on the road you are running or a headwind during the logs or something hardware wise is going on. Something like a clogged cat, a leaking diverter valve, or severely clogged airfilter are some of the things that could lead to such a large offset.

You can certainly try the 2 tunes back to back and you should see differences that are much smaller than what you are seeing. I recommend retaking logs and if possible going back and forth on the same stretch of road as a beginning step.

 

[brbauer2]

Had a look at the datalogs are clean. Boost is within expected range, timing is as well with no knock interfering.

The temperatures are not very hot either.

The shapes of the power graphs from your latest runs are what they should be - they are just offset down. This usually indicates an issue in the setup with virtual dyno or a consistent grade incline or some sort of headwind.

Double check that the vehicle data such as the gearing and frontal area are correctly setup.

Looked closer at the datalogs side by side. The tune in spite of the heat is running very similar boost as well as timing curves which are largely responsible for power output. The early logs were taken near freezing temperatures but the offset in acceleration time between the 2 is more than what temperature would result in.

So one of 2 things are going on here. Either there is a grade on the road you are running or a headwind during the logs or something hardware wise is going on. Something like a clogged cat, a leaking diverter valve, or severely clogged airfilter are some of the things that could lead to such a large offset.

You can certainly try the 2 tunes back to back and you should see differences that are much smaller than what you are seeing. I recommend retaking logs and if possible going back and forth on the same stretch of road as a beginning step.

Both sets are taken on the same road using the same tune - a log revised flash tune. One run northbound and one run southbound on each set. The data is loaded up using the same vehicle profile in VDyno.

Now that I think about it I did install my GFB DV+ after the first set of logs. What in the data would I be looking for to show a leak in the diverter valve so I know if I resolve the issue? Would a leak in the DV just show up in logs as lower power? My butt dyno doesn't feel that I've lost as much as is shown, if any at all.

I'll take a look at the filter (cleaned 4k miles ago). Stock DP, just passed 14K miles.

 

[Quasar]

[*]15" Winter wheels -> 17" Summer wheels (~3lb/corner heavier)

Did you change the tire/wheel size in VDYNO under the car settings? This makes a huge difference and is likely a result of the large differences you are seeing if you did not adjust the size to account for this.

 

[DvC]

Did you change the tire/wheel size in VDYNO under the car settings? This makes a huge difference and is likely a result of the large differences you are seeing if you did not adjust the size to account for this.

Good catch

 

[brbauer2]

Did you change the tire/wheel size in VDYNO under the car settings? This makes a huge difference and is likely a result of the large differences you are seeing if you did not adjust the size to account for this.

Just double checked and replugged in the correct tire size and the overall diameter changes from 24.21" -> 24.26" between the 15" & 17".

That change was good for 4hp though.

Just a comparison using an online tire size calculator.

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[Alex@Stratified]

Double check the diverter valve as well. It has hard to tell if it is sealing inside the housing but you could swap back to OEM config for a quick back to back test.

 

[haste]

Traction control completely turned off for all runs?