Dyno day: issues again?? What's going on with this graph?

iqraceworks · 08-17-2022, 01:42 PM

Quote:

Originally Posted by Leanped

Out of curiosity, why is it that boost stays so high after accel. pedal drops to 0? Wouldn't the BOV drop boost immediately? also, with all that boost still present, I noticed some AFR spikes. That might cause knock and timing corrections, no?

Just trying to learn and understand. Thanks!

Great point...I didn't notice that until you mentioned it. Yes, the BOV should dump the boost pressure almost immediately. A good BOV should dump boost within a couple tenths of a second....as soon as the throttle is closed. His logs look like it's taking almost a full second or more to dump all the boost. That could definitely cause some weird issues. The DME is going to get into some strange fuel/timing table areas with a closed throttle, and lots of boost. The DME sees the boost and dumps in more fuel....but the throttle is closed, so the AFR goes way rich......this could definitely cause some of those misfire/knock issues at the end of the pull.

I'm guessing that either the BOV is not set up correctly and/or the line running to it is very undersized. But yes....it should dump boost pressure almost instantly.

OP...what type of BOV setup are you running?

Quick335XI · 08-17-2022, 03:56 PM

Quote:

Originally Posted by iqraceworks

Like you said...the log looks great. You are meeting boost targets, AFR's are perfect, no timing corrections, HPFP rail pressure is good, IAT's not crazy high...no issues at all.

If you did the pull in 4th on the dyno vs. 3rd on the street...YES, you are going to put a lot bigger load on the motor, for a longer period of time. I wouldn't worry about timing corrections after you let off the gas at the end of the pull. The dyno is going to force the motor to slow down much faster than if you were just coasting down on the street...so that might be some of it. I would be curios if you had the same issues if you did a pull in 3rd gear.

In the end...as long as your car runs great on the street, I wouldn't get to worried about some small quirks on a chassis dyno. It's not uncommon to have a car run good on a dyno, and have quirks on the street that need to be worked out......and vise-versa.

Thanks! That's what i was also thinking.

I did a couple pulls on the stree last night... ZERO issues.

I am, however, going to go through the VTT B58 coil conversion...

iqraceworks · 08-17-2022, 04:04 PM

Quote:

Originally Posted by Quick335XI

Thanks! That's what i was also thinking.

I did a couple pulls on the stree last night... ZERO issues.

I am, however, going to go through the VTT B58 coil conversion...

What BOV setup are you using? The log looks like it's holding boost even after you let off the gas......and that BOV should dump pressure instantly. That could have caused those knocking and misfire issues when you let off the gas on the Dyno pull.

ErvGotti · 08-18-2022, 09:28 AM

Quote:

Originally Posted by Quick335XI

Fairly fresh ngk two step colder gapped around 20, and Eldor coils. I've been reading the eldors are good to around 600; maybe that's part of this issue, since I'm a solid 640 and could probably do more if I wasn't seeing this issue up high... What are some coils that are good for big power? I'm reading on the b58 conversions.

I have PR coils, but they were the only plug n play coils at the time, not issues but I'm only around 500 whp

Quick335XI · 08-19-2022, 10:16 AM

Quote:

Originally Posted by iqraceworks

What BOV setup are you using? The log looks like it's holding boost even after you let off the gas......and that BOV should dump pressure instantly. That could have caused those knocking and misfire issues when you let off the gas on the Dyno pull.

It's a Tial... is there something I could check on it? Yeah maybe that's the problem...

Quick335XI · 08-19-2022, 10:17 AM

Quote:

Originally Posted by ErvGotti

I have PR coils, but they were the only plug n play coils at the time, not issues but I'm only around 500 whp

These eldors are good for around 600 which seems to be where it's time to move to something like PR or s55, or b58. I'm going with the B58 conversion from vtt, hopefully that addresses this issue...

iqraceworks · 08-19-2022, 10:24 AM

Quote:

Originally Posted by Quick335XI

It's a Tial... is there something I could check on it? Yeah maybe that's the problem...

The first things I would do is see what it's doing at idle....it should just be lightly closed. It should have the plain colored 10psi spring in it. Also, make sure you have the correct sized 1/4 (inner diameter) line running to it from the manifold.

When you are on boost, and let off the gas.....do you hear the BOV "Woooosh" noise? If not, it's definitely not dumping the boost.

feuer · 08-20-2022, 03:23 PM

Quote:

Originally Posted by Quick335XI

These eldors are good for around 600 which seems to be where it's time to move to something like PR or s55, or b58. I'm going with the B58 conversion from vtt, hopefully that addresses this issue...

Not necessarily. My ST n54 runs ok on the OEM Bosch coils at 30psi making more than 600 horse power. I have the same on the TT n54 also. I track them both. So they see a lot of abuse. Both have PI so perhaps that helps a little with longevity. Coincidently both sat for few weeks and had mysfire on cyl2 immediately after i started them. It was the coils on both. Super weird coincidence. A friend gave me his old n55 coils after upgrading to b58 so I will be trying those too.

Quick335XI · 08-24-2022, 10:16 AM

Quote:

Originally Posted by iqraceworks

The first things I would do is see what it's doing at idle....it should just be lightly closed. It should have the plain colored 10psi spring in it. Also, make sure you have the correct sized 1/4 (inner diameter) line running to it from the manifold.

When you are on boost, and let off the gas.....do you hear the BOV "Woooosh" noise? If not, it's definitely not dumping the boost.

Yes, it makes that sounds

CarAbuser · 08-24-2022, 12:57 PM

Not a BOV problem. His target target load is staying high after letting off the pedal so his throttle will still be wide open.

It's an issue with the tune. Not uncommon to see tuners make mistakes like that in the load target. Who is your tuner?

iqraceworks · 08-24-2022, 01:42 PM

Quote:

Originally Posted by CarAbuser

Not a BOV problem. His target target load is staying high after letting off the pedal so his throttle will still be wide open.

It's an issue with the tune. Not uncommon to see tuners make mistakes like that in the load target. Who is your tuner?

Cool! Great info!

Quick335XI · 08-30-2022, 08:47 PM

Tuner is JSR... He sent an update but I haven't been able to install it yet because I had a shop install the VTT b58 coil conversion kit today. . before that. I could connect fine to my MD thru wireless adapter. and now all of a sudden when I go to connect to MHD, I've tried really hard and it just won't connect anymore. I have the wifi adapter. Does anyone know if maybe there was something they didn't connect back up that would cause this? I've disconnected and reconnected the wifi adapters have tried everything. I can't flash the cer anymore

Quick335XI · 08-31-2022, 10:31 AM

Quote:

Originally Posted by Quick335XI

Tuner is JSR... He sent an update but I haven't been able to install it yet because I had a shop install the VTT b58 coil conversion kit today. . before that. I could connect fine to my MD thru wireless adapter. and now all of a sudden when I go to connect to MHD, I've tried really hard and it just won't connect anymore. I have the wifi adapter. Does anyone know if maybe there was something they didn't connect back up that would cause this? I've disconnected and reconnected the wifi adapters have tried everything. I can't flash the cer anymore

So, this morning MHD pushed another update... They must have had a bug in the last version. I was able to connect and flash the car... Looking forward to a couple pulls with the new plugs and coils at lunch!!

Quick335XI · 09-08-2022, 09:31 PM

Quote:

Originally Posted by CarAbuser

Not a BOV problem. His target target load is staying high after letting off the pedal so his throttle will still be wide open.

It's an issue with the tune. Not uncommon to see tuners make mistakes like that in the load target. Who is your tuner?

Hey this actually sent us in the right direction... much thanks!!

I also upgraded the coils and plugs using VTT kit to B58... car is running unbelievable. Turbo's are now the bottleneck, running out of steam up top... https://datazap.me/u/terryeaton/log-...og=0&data=3-21

08-24-2022, 12:57 PM	#32
CarAbuser Lieutenant Colonel 487 Rep 1,551 Posts Drives: Z4 35i DCT / E92 335i DCT Join Date: Jul 2010 Location: United Kingdom iTrader: (0)	Not a BOV problem. His target target load is staying high after letting off the pedal so his throttle will still be wide open. It's an issue with the tune. Not uncommon to see tuners make mistakes like that in the load target. Who is your tuner?
	Appreciate 0 Quote

08-30-2022, 08:47 PM	#34
Quick335XI First Lieutenant 117 Rep 338 Posts Drives: 2010 335xi Join Date: Dec 2017 Location: Dallas iTrader: (0)	Tuner is JSR... He sent an update but I haven't been able to install it yet because I had a shop install the VTT b58 coil conversion kit today. . before that. I could connect fine to my MD thru wireless adapter. and now all of a sudden when I go to connect to MHD, I've tried really hard and it just won't connect anymore. I have the wifi adapter. Does anyone know if maybe there was something they didn't connect back up that would cause this? I've disconnected and reconnected the wifi adapters have tried everything. I can't flash the cer anymore
	Appreciate 0 Quote