Overboosting

[twyztid]

Has anyone experienced an overboost issue with their tuned Sidewinder? My brother-in-law has a Precision EFI 280hp tuned 2017 ZR9000. He is supposed have a max of 16-16.5psi but is consistently getting 18-18.5psi. That tune still uses the stock 2-bar MAP sensor so this is a problem. He ran lean enough last season to take out a piston and erode away some of the head surface. He has had the engine rebuilt and replaced the head casting and is trying to track down the problem.

He replaced the turbo at the end of last season thinking that was causing his oil consumption problem (it wasn't... it was the bad piston). He has swapped the MAP sensor, barometric pressure sensor, and wastegate solenoids with known working units and verified that there are no leaks in the lines. He has also verified that his boost gauge IS reading the correct pressure. Still... the boost is 1.5-2psi higher than it should be. Precision EFI isn't really any help.

Any ideas?

 

[Turboflash]

1. Was he running same PEFI tune last year when it deto-ed and took out a piston? PEFI tunes were some of the first 998 tunes (back in 2017) that had enhanced knock sensor sensitivity standard. Difficult to hurt engine because as soon as there are 3 deto counts, the ECM is already pulling back ignition timing and reducing boost. How/why on that sled it would run in deto state long enough to damage head and piston?
2. Which muffler? PEFI Stage 3 requires 2.5" muffler minimum.
3. What is BOV?
4. Is airbox stock?
5. Is waste gate at stock location?
6. With anything he replaced (sensors, turbo, etc - did he use genuine OEM parts, or aftermarket?
7. What RPM is he running?
8. Is exhaust manifold stock?

 

[twyztid]

1. Was he running same PEFI tune last year when it deto-ed and took out a piston? PEFI tunes were some of the first 998 tunes (back in 2017) that had enhanced knock sensor sensitivity standard. Difficult to hurt engine because as soon as there are 3 deto counts, the ECM is already pulling back ignition timing and reducing boost. How/why on that sled it would run in deto state long enough to damage head and piston?
2. Which muffler? PEFI Stage 3 requires 2.5" muffler minimum.
3. What is BOV?
4. Is airbox stock?
5. Is waste gate at stock location?
6. With anything he replaced (sensors, turbo, etc - did he use genuine OEM parts, or aftermarket?
7. What RPM is he running?
8. Is exhaust manifold stock?

1. Yes, same tune as last season. It is actually a Speedwerx tune but they use Precision EFI.
2. He is running a 2.5" Speedwerx Stage 2 muffler. https://speedwerx.com/l2-series-lig...2017-2020-zr-xf-m-9000-yamaha-sidewinder.html
3. I believe he is using the stock BOV but I could be wrong. When would a bad BOV cause overboost?
4. Yes, stock airbox.
5. Yes, stock wastegate on both old turbo and new turbo that was installed late last season (still using this turbo)
6. All sensors & solenoid replaced are OEM that he is borrowing from a friend's properly running, 500-mile 2018 Thundercat.
7. I don't have an answer to this.
8. Yes, stock exhaust manifold.

 

[Todd Beenen]

Just a thought, maybe check with speedwerx, they have always been helpful

 

[1nc 2000]

Sounds to me they installed the wrong tune.
Going over the limit of the stock fuel pump.
Also I have not heard of the 2bar map sensor reading that high. I was told 16.8 psi was max for 2 bar map sensor.

 

[twyztid]

Just a thought, maybe check with speedwerx, they have always been helpful

I believe he has talked to both Speedwerx and directly to Precision EFI

 

[twyztid]

Sounds to me they installed the wrong tune.
Going over the limit of the stock fuel pump.
Also I have not heard of the 2bar map sensor reading that high. I was told 16.8 psi was max for 2 bar map sensor.

Yes, that is correct. He is supposed to be at either 16psi or 16.5psi... max. His boost gauge has been tested to be accurate and it is reading in the 18 to 18.5psi range. This is a problem since, like you said, the stock MAP sensor can't read that high so it doesn't know that it needs more fuel so it becomes a lean condition and has detonation.

 

[twyztid]

Can anyone tell me if it is possible to swap ECUs between 2 tuned 2017 ZR9000's? He is currently in the UP with a friend that has also has a tuned ZR9000. That other one has a Turbodynamics Max Spool 17 tune on it. Would it be possible to swap ECUs and see what happens with the boost? I am wondering if that would help determine if it is a bad tune or if there is still some issue with something else in his sled and not the tune.

 

[Surestick]

Could there be a restriction in the wastegate plumbing or something stopping the wastegate from opening fully?

 

[twyztid]

Could there be a restriction in the wastegate plumbing or something stopping the wastegate from opening fully?

He's checked the tubing and the same thing is happening with 2 different turbos. I find it unlikely that the problem would stay the same with 2 different wastegates attached to 2 different turbos.

 

[Todd Beenen]

I believe he has talked to both Speedwerx and directly to Precision EFI

They didn’t have any idea?

 

[justinator]

I think you can swap the ecu’s with no problems, I have never tried personally but I remember someone on one of the facebook groups swapping one to test something, I may be mistaken though its been a while. I do not know how the knock system on precision tunes is programmed to work but from what I understand with Td and possibly hurricane is the ecu retards timing to eliminate knock and when it maxes out the ability to pull timing(2-2.5 degrees I believe) it will activate the knock lights.......same concept as most modern 2 strokes. So when the sled lost the piston was the knock protection working or did he continue to hold it with knock light activated?? Or did the engine finally fail and upon dissasembly notice the lean running and knock damage? Kinda sounding like a flash issue to me or a flash designed to run a 3 bar sensor??? I know you cant mix up tunes and sensors with td and hurricane because it will give you a map sensor calibration error but not familiar with precisions software and flashes. Keep us posted to whatever progress you make. Very interested to learn whats going on here.

 

[sideshowBob]

I think you can swap the ecu’s with no problems, I have never tried personally but I remember someone on one of the facebook groups swapping one to test something, I may be mistaken though its been a while. I do not know how the knock system on precision tunes is programmed to work but from what I understand with Td and possibly hurricane is the ecu retards timing to eliminate knock and when it maxes out the ability to pull timing(2-2.5 degrees I believe) it will activate the knock lights.......same concept as most modern 2 strokes. So when the sled lost the piston was the knock protection working or did he continue to hold it with knock light activated?? Or did the engine finally fail and upon dissasembly notice the lean running and knock damage? Kinda sounding like a flash issue to me or a flash designed to run a 3 bar sensor??? I know you cant mix up tunes and sensors with td and hurricane because it will give you a map sensor calibration error but not familiar with precisions software and flashes. Keep us posted to whatever progress you make. Very interested to learn whats going on here.

My biggest concern here is that the Knock system never protected the engine.
This issue needs to be taken up with the Vendor or the tune provider.
I run Hurricane tunes and Dave said the Knock system is designed to protect the engine under the most abusive of operators.
All the tune providers I would think have a similar protective Knock systems

 

[Chris Rose]

Can anyone tell me if it is possible to swap ECUs between 2 tuned 2017 ZR9000's? He is currently in the UP with a friend that has also has a tuned ZR9000. That other one has a Turbodynamics Max Spool 17 tune on it. Would it be possible to swap ECUs and see what happens with the boost? I am wondering if that would help determine if it is a bad tune or if there is still some issue with something else in his sled and not the tune.

You can swap ECU with another from the same year. I am currently running that scenario, different tune than yours.

 

[twyztid]

They didn’t have any idea?

Not really.