Honda Power Unit Hardware & Software

[63l8qrrfy6]

So HPD's post does suggest good old bearing issues.

I assume that the turbine wheel has its own bearing(s) so maybe these would have failed first if the problem was to do with exhaust side temperatures.

Keep in mind that EGT is north of 1000C while the magnets Curie temps are under 800C and they most likely operate a lot lower than that.

The fact that the relatively cooler MGUH bearing failed could mean that the friction in the bearing is too high , leading to high heat generation and race distortion.
This could be due to the preload being too high and/or insufficient oil flow. Normally preloads are kept high enough to maintain bearing stiffness and load capacity at high speeds, however the downside is an increase in friction torque (and therefore heat). This is typically countered by increasing the oil flow which further increases the power losses.
As a result there is a very fine balance between mechanical failures (hertzian stress), thermal failures (race distortion) and bearing frictional losses.

Maybe Honda were too aggressive in reducing bearing losses and neglected reliability. That or they are failing to determine the mechanical loads on the bearings - which is often a challenge with high speed rotating machinery.

[bigblue]

[...]
MGU-H bearing failure is a result of unforeseen multi-directional stress on the shaft and entire casing that houses the bearings.
[...]

Just a reminder of a previous post abut the MGU-H, to add to the latest.

[henry]

I believe the engine shut down because the monitoring system detected a loss of pressure in the MGU-H. I had assumed this was cooling water pressure although I suppose it might be oil pressure to the bearings.

If it was cooling water pressure this would mean that the failure mode of the bearings was that it allowed sufficient shaft excursions to damage the seals for the water cooling system.

[Wazari]

[...]
MGU-H bearing failure is a result of unforeseen multi-directional stress on the shaft and entire casing that houses the bearings.
[...]

Just a reminder of a previous post abut the MGU-H, to add to the latest.

The first issue I am told has been addressed. I have just been told about the MGU-H temps from engine telemetry and they are not in the "designed" range.

When the season is over I will go into detail as to the reason why the Spec 4 PU was not implemented this season from HRD and McLaren sources.

[godlameroso]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

[Singabule]

The 2016 spec turbine is nearly perfect to handle heat issue, so nothing to do for 2017 turbine though. Multidimentional stress from longer mguh shaft take account for most of the bearing issue. Temperature could affect material property such as stiffness from material expansion, so i think one single issue is not the cause, but several issue in the same time. Again, i think honda is far too aggressive in designing parts, an over engineering issue

[ringo]

I believe the engine shut down because the monitoring system detected a loss of pressure in the MGU-H. I had assumed this was cooling water pressure although I suppose it might be oil pressure to the bearings.

If it was cooling water pressure this would mean that the failure mode of the bearings was that it allowed sufficient shaft excursions to damage the seals for the water cooling system.

The failure mode may also have nothing to do with the MGUH parts themselves. Could be a cooling system leak that lead to overheating, which will now point to quality issues with these little seemingly insignificant parts.

But if it's the MGUH bearings, i guess Honda can take a look at their oil and water cooling, and even something as simple as flushing these cooling systems out after each weekend could mitigate these kinds of failures.
Another solution is not bother with being too precise and do a bit of good ol american engineering.. beef up the shaft gaddamit!

[diffuser]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

[PlatinumZealot]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

I don't think it has anything to do with the transmission (a McLaren Part)!
My guess is they did not see the reliability on the dyno. Remember this is more boost, more power, more heat from Team Wazari being put into a frankenstein (Team A) engine block. That block is already homologated. Simply put, they need an entirely new engine block to build Team Wazari's spec four properly.

[gofast182]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

I don't think it has anything to do with the transmission (a McLaren Part)!
My guess is they did not see the reliability on the dyno. Remember this is more boost, more power, more heat from Team Wazari being put into a frankenstein (Team A) engine block. That block is already homologated. Simply put, they need an entirely new engine block to build Team Wazari's spec four properly.

Good point. We have to presume this already exists per Wazari's comments. Then on the McLaren front it makes sense that chassis/cooling implications are not worth solving late in the season and with the partnership ending. From there it's a matter of how creative Honda have decided to get in terms of testing. Dyno only or has it been run in a chassis of some sort? For the sake of their reputation (and potential comeback story) I hope the latter.

[makecry]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

I don't think it has anything to do with the transmission (a McLaren Part)!
My guess is they did not see the reliability on the dyno. Remember this is more boost, more power, more heat from Team Wazari being put into a frankenstein (Team A) engine block. That block is already homologated. Simply put, they need an entirely new engine block to build Team Wazari's spec four properly.

I dont think that's the right use of the word "homologated". Every part needs to be homologated to be able to race in any motorsports which are governed by regulation. To homologate means to determine whether or not a particular part is legal to be raced .

[ziggy]

I can guess more or less why, it would require modifying the chassis/transmission in order to fit spec 4. Not enough time to modify the chassis, and now with Honda joining TR, no desire to do so from either Honda or McLaren.

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

I don't think it has anything to do with the transmission (a McLaren Part)!
My guess is they did not see the reliability on the dyno. Remember this is more boost, more power, more heat from Team Wazari being put into a frankenstein (Team A) engine block. That block is already homologated. Simply put, they need an entirely new engine block to build Team Wazari's spec four properly.

Considering that both cars had the same problem in the last race weekend, whatever it was (MGUH bearing?), suggests that Honda still has fundamental problems, not only with the ICE. It simply makes no sense for both parts to run a new PU till the problems are solved with the old one. It can only become worse.

[etusch]

I think that is a very plausible reason ....If that is the case .....why would that reason need to wait till the end of the season? Pretty benign reason no?

I don't think it has anything to do with the transmission (a McLaren Part)!
My guess is they did not see the reliability on the dyno. Remember this is more boost, more power, more heat from Team Wazari being put into a frankenstein (Team A) engine block. That block is already homologated. Simply put, they need an entirely new engine block to build Team Wazari's spec four properly.

Considering that both cars had the same problem in the last race weekend, whatever it was (MGUH bearing?), suggests that Honda still has fundamental problems, not only with the ICE. It simply makes no sense for both parts to run a new PU till the problems are solved with the old one. It can only become worse.

I think this comment lost maximum real world testing logic

[godlameroso]

The problem isn't with the ICE, but the MGU-H, we only had one single ICE faliure during this season as far as I'm aware. The rest of the problems have been elsewhere, oil tank, hydraulics, shafts, bearings.

Vandoorne's spec 3.8 is essentially new cylinder heads.

[dren]

If spec 4 was firstly planned to debut in SPA, why would the chassis implementation be so different from the actual car? Wouldnt Mclaren be already prepared to accomodate this PU before the partnership broke up?

Changing PU installation mid season makes any sense in development through a season?

Not trying to be mean, Im genuinely curious.

If the heads are larger (we've heard they cause the PU to have a higher CoG), then some cooling solutions on the chassis side may need to be rerouted or massaged a bit to get everything to fit. Mclaren may not want to put in the resources at this point for marginal gains that won't affect their standings in the championship. Just a guess.