Pure Turbos Stage 3 (PS3) dyno results for N55

[houtan]

Hey there. Sorry didn’t realize you posted some questions. My motor is stock.

The Pure750 is the final version of the prototype on my car. Should have better spool and make 600whp no problem.

Having said that, if you are DCT, don’t expect to get much more than 575whp. I have plenty of boost left but if I approach 600whp my car goes into limp mode with a cylinder 4, 5, or 6 misfire. But there are no actual misfires.

I believe it’s something in the tune but I need MHDs help. Unfortunately they don’t have the bandwidth to assist right now so I follow up with them every few months. But my car is fast the way it sits so I am not in a huge rush. Would be nice to figure though.

[domohockey]

Does the stock hpfp handle this power or did you upgrade it along with the lpfp

[houtan]

Fueling mods from OP: PI spacer with 950cc injectors, AIC, Walboro 535 pump in PFS DIY bucket, E57 on dyno day.

I need to add in there the BPM4.

I am early E-series N55 so there is no high-pressure fuel pump upgrade. My pump is the same as the N54. Hopefully this helps but feel free to ask any additional questions you may have.

[AmuroRay]

Originally Posted by houtan

Hey there. Sorry didn’t realize you posted some questions. My motor is stock.

The Pure750 is the final version of the prototype on my car. Should have better spool and make 600whp no problem.

Having said that, if you are DCT, don’t expect to get much more than 575whp. I have plenty of boost left but if I approach 600whp my car goes into limp mode with a cylinder 4, 5, or 6 misfire. But there are no actual misfires.

I believe it’s something in the tune but I need MHDs help. Unfortunately they don’t have the bandwidth to assist right now so I follow up with them every few months. But my car is fast the way it sits so I am not in a huge rush. Would be nice to figure though.

You sure it's not a transmission torque limit issue?

[houtan]

Originally Posted by AmuroRay

You sure it's not a transmission torque limit issue?

I am not. But, I am running xHP stage 3 which supposedly removes or increases all torque limiters.

In addition, I recently paid someone overseas that has been doing custom DCT tunes before xHP even came out hoping there was something missing in xHP in terms of raised torque limiters. Still have the same issue. So this makes me think it’s not transmission related.

[wheela]

Originally Posted by houtan

I am not. But, I am running xHP stage 3 which supposedly removes or increases all torque limiters.

In addition, I recently paid someone overseas that has been doing custom DCT tunes before xHP even came out hoping there was something missing in xHP in terms of raised torque limiters. Still have the same issue. So this makes me think it’s not transmission related.

As misfire is detected by the crank position sensor, I suspect there is some interaction between the motor and DCT at high power levels where crank twist causes the misfire detection to erroneously trip. I doubt the DME compensates for crank twist, so it seems plausible that as crank twist increases, there would be a point where the contributions from the various cylinders' power stroke would appear to not be happening at the correct time based on crank position (if the crank is twisting, then the end of the crank opposite the crank position sensor will be at a worst-case different rotational position than indicated by the crank position sensor - it would be further off the further you get from the crank position sensor). This is also why I suspect you can influence the problem by changing fly wheels - the different rotational inertia would influence the crank twist harmonics. I have no hard proof to back it up, this is just my theory.

[houtan]

thanks wheela. i will look into how i can soften up the crank position detection.

the other thing i forgot to mention is my current tune should have all torque monitors disabled, including throwing a cel, but for whatever reason it still happens. not sure if i entered the wrong value or maybe it is not implemented correctly in the xdf or mhd.

screenshot of my current setting for tq monitors.

[Boostedphil698]

Does anyone know what the max whp this thing can put out is? Fueling is a major issue on these cars. I know ET3 just released a EKP that can run a dual pump setup. Finding a shop that can wire it in might be the tough part.... that's what I'm finding. You really need the percision raceworks stage 3 LPFP setup to maximize returns. Hobs switch is dicey.

[houtan]

Does anyone know what the max whp this thing can put out is? Fueling is a major issue on these cars. I know ET3 just released a EKP that can run a dual pump setup. Finding a shop that can wire it in might be the tough part.... that's what I'm finding. You really need the percision raceworks stage 3 LPFP setup to maximize returns. Hobs switch is dicey.

Thanks for your post.

By “this thing”, are you referring to the turbo? If so, my guess is 650whp should not be an issue.

By “these cars”, I am assuming you mean n55 powers cars. But are you referring to early e series, late e series, or f series n55 cars? They are slightly different and definitely do not enjoy the same tuning support.

I have never heard of ET3. Any links. I have been running a BPM4 for a few years now. Not one issue. And it can control/activate multiple pumps I believe. I know it can control two lpfp for sure.

Also, what fuel/ power level are you assuming when you say three pumps would be required?

[Boostedphil698]

Originally Posted by houtan

Thanks for your post.

By “this thing”, are you referring to the turbo? If so, my guess is 650whp should not be an issue.

By “these cars”, I am assuming you mean n55 powers cars. But are you referring to early e series, late e series, or f series n55 cars? They are slightly different and definitely do not enjoy the same tuning support.

I have never heard of ET3. Any links. I have been running a BPM4 for a few years now. Not one issue. And it can control/activate multiple pumps I believe. I know it can control two lpfp for sure.

Also, what fuel a slower level are you assuming when you say three pumps would be required?

I was referring to the max hp attainable on the Pure 750. Stage 3 lpfp is a dual pump setup. Two walboro 450s. BPM4 is also no longer being offered. The person who runs ET3 is a former Bosch engineer and has 40 patents to his name. He released an upgraded EKP that you can run a dual setup on.

[niceast]

Ooo been waiting
Is this the drop, pure was teasing ps800 two years ago.

Need a second tester in cooler air? Send me a care package in Seattle.

[houtan]

Originally Posted by wheela

As misfire is detected by the crank position sensor, I suspect there is some interaction between the motor and DCT at high power levels where crank twist causes the misfire detection to erroneously trip. I doubt the DME compensates for crank twist, so it seems plausible that as crank twist increases, there would be a point where the contributions from the various cylinders' power stroke would appear to not be happening at the correct time based on crank position (if the crank is twisting, then the end of the crank opposite the crank position sensor will be at a worst-case different rotational position than indicated by the crank position sensor - it would be further off the further you get from the crank position sensor). This is also why I suspect you can influence the problem by changing fly wheels - the different rotational inertia would influence the crank twist harmonics. I have no hard proof to back it up, this is just my theory.

Thanks wheela. This makes sense to me. I was thinking, though, how come the f series n55s do not have this issue. I am not sure, but I dont think the MT e series N55s run into this issue as well, but not sure. Either way, I started to test your theory haha.

I softened the knock detection tables in cyldners 4, 5, and 6, increased the misfire per bank from 420 to 800, increased the knock detection threshold for group 2 (table we got from the f series cars). Basically, my current values match or are slightly more conservative than the f series tables.

This issue usually shows up in 5th, always at 5900ish rpm, which is hard to test because the speed is high. So i upped my boost to 27ish psi, so it would trigger in 4th if still present. And, it did, grrrrrrrr. codes are below.

Log is on SS. https://www.s po o ls t r e et.com/graphs/log-09-17-2023-22-03-17.30147/

Anyone know any F series n55 tuners? I wonder if they make adjustments to these tables on higher hp builds.

[houtan]

Just a minor update to the original post. Been working on figuring out the misfire issue at 600 whp with friends and forum members and we figured out a way to completely disable misfire detection. Tried it out and it worked, allowing me to run 26-27 psi. Car is a lot faster and ran a great 100-200 time which I added to the original post as well as here:

[houtan]

Updated the original post. Been working on the tune and the old girl is still picking up some speed. Still full weight, still on street tires (kumho v730)


100-200kmh


60-130

[DWN-N-OUT]

Sorry for the thread revival, but did you ever get your misfire figured out houtan? I'm looking to upgrade my turbo in the near future and was debating between the Pure 750 and a full frame kit but a full frame kit seems a little overkill if the DCT is gonna limit me before the Pure 750 does.

[houtan]

All good. I’ve been meaning to update the thread actually. Switched to straight e85 and picked up a little more speed. I will get my dragy time posted here shortly.

With regard to the misfire, the answer is kind of. We found a table that allows us to disable misfire detection by RPM so above 5500 we disable it. There were a lot of theories on why the misfire happens even though the log looks good. But I think FrankenTurbo on Facebook shared information that solves the mystery. Basically at higher boost levels there is an uneven flow of fuel and cylinders 1, 2 and 3 run leaner at higher boost, which causes the misfire. He basically put I believe EGT sensors, or may have been O2 sensors, on each cylinder on the exhaust manifold and shared the data.

Not sure what the correct fix will be, but for me personally, I maximize fuel through port injection. Hopefully that keeps the AFR on all the cylinders in a safe range.

[houtan]

Switched to full e85. Here are my current times that I will add to the op.

[wheela]

Originally Posted by houtan

All good. I’ve been meaning to update the thread actually. Switched to straight e85 and picked up a little more speed. I will get my dragy time posted here shortly.

With regard to the misfire, the answer is kind of. We found a table that allows us to disable misfire detection by RPM so above 5500 we disable it. There were a lot of theories on why the misfire happens even though the log looks good. But I think FrankenTurbo on Facebook shared information that solves the mystery. Basically at higher boost levels there is an uneven flow of fuel and cylinders 1, 2 and 3 run leaner at higher boost, which causes the misfire. He basically put I believe EGT sensors, or may have been O2 sensors, on each cylinder on the exhaust manifold and shared the data.

Not sure what the correct fix will be, but for me personally, I maximize fuel through port injection. Hopefully that keeps the AFR on all the cylinders in a safe range.

Thanks for sharing! I haven't heard anything about that Frankenturbo theory, not on Facebook, lol. I'd love to review the details if there was any way. But isn't the misfire issue limited to DCT cars? If so, that would seem to blow a hole in that theory

[houtan]

I don’t think it’s DCT only. Maybe we were the only ones posting?

This is the post: https://www.facebook.com/groups/2448...476613958363/?


Let me know what you think.

[wheela]

Originally Posted by houtan

I don’t think it’s DCT only. Maybe we were the only ones posting?

This is the post: https://www.facebook.com/groups/2448...476613958363/?


Let me know what you think.

Private group, I can't see without facebook😕

[houtan]

Originally Posted by wheela

Private group, I can't see without facebook😕

Well, you wouldn’t be the first person to add Facebook because of the N55 haha.

I don’t think there’s a way to download the post and there’s a lot of information there. But if I figure a way out, I’ll let you know.

[wheela]

Originally Posted by houtan

Well, you wouldn’t be the first person to add Facebook because of the N55 haha.

I don’t think there’s a way to download the post and there’s a lot of information there. But if I figure a way out, I’ll let you know.

Haha, yeah I may need to break down and join someday. Thanks brother!