POLL on the bulging undertray: occurence and effects

[NLMGSAN]

There is substantial information in this forum about undertray related issues. It varies from from suggested negative aerodynamical effects that increases power consumption up to undertrays breaking and falling off.

To get a better understanding of the issue we will start with a simple poll first. Collecting a sufficient number of answers allows us to better understand the extent of the problem and and visible characteristics resulting from the bulging undertray. The visible characteristics are discussed in the following thread
MG4 Undertray dip/bulge and may look like this:

With this information we may be of help to all MG4 users who would like to have a fix for the issue. it may also be the start of another poll if more information is needed.

There are plenty of MG4 owners here, both with and without undertray issues. However, it is important that both groups respond to the poll!

Because of the limited options of the internal poll this one is placed elsewhere. Click on the link below:
Undertray Poll (closed!)

At the end of the survey, ignore the dutch page where they ask you for an email adress. They just ask you to create your own account for making your own surveys.

 

[AndyL61]

I personally think the dirt marks are from air entering the gap at the bottom of the door going along the sills until it hits the wheel arch at which point it goes up the wheel arch and exits where you're seeing the dirt. It is always dirty along the sills in bad weather which is why you see the dirt. Happened on lots of cars I've owned. Nothing to do with undertray in my humble opinion.

 

[NLMGSAN]

We will see Andy. I just need enough data.

 

[Burgo]

Did survey, but then was presented with a page in Dutch(?) babbling on about email addresses??

 

[NLMGSAN]

I will have a look.

Edit: ignore this page in Dutch. It is just asking you to create your own account for making your own surveys.

 

[siteguru]

I saw the same but knew what it was about. (I don't speak or read Dutch, but I'm familiar with how these survey sites work so knew I could just close the tab).

 

[NLMGSAN]

We are supposed to have way over 600 members (check the poll on mg4 satisfaction) and only 20 responded!!

If we would like to use this poll for benefit of our members we must do better.

 

[Bam Bam]

We are supposed to have way over 600 members and only 20 responded!!

If we would like to use this poll for benefit of our members we must do better.

Not everyone on here has an MG4 though.

I do and already completed the poll!

 

[NLMGSAN]

Update on the stats.
Only 24 people answered the questions. Roughly 2/3 reported an undertray issue, and 2/3 of the issues were present from day 1.
Given that more than 695 mg4 users responded in the central poll, there doesn't seem to be much attention for the undertray issue. The actual size of the problem could very well be much smaller than suggested from the responses so far.

 

[NLMGSAN]

Since response is low and I need to pay for extending it, I will close the poll.

Final result are (N=25):
64% report bulging. 16% report bulging an dirt traces, but 32% report the traces without bulging. Though numbers are small, there is no indication that there is a link between bulging and dirt traces.

70% had bulging from day 1, nobody reported damage. 76% of the responses are from uk/wales/n.i/scotland and 20% EU.

 

[Rolfe]

That's useful.

 

[turntoport]

There is substantial information in this forum about undertray related issues. It varies from from suggested negative aerodynamical effects that increases power consumption up to undertrays breaking and falling off.

To get a better understanding of the issue we will start with a simple poll first. Collecting a sufficient number of answers allows us to better understand the extent of the problem and and visible characteristics resulting from the bulging undertray. The visible characteristics are discussed in the following thread
MG4 Undertray dip/bulge and may look like this:


View attachment 26595

With this information we may be of help to all MG4 users who would like to have a fix for the issue. it may also be the start of another poll if more information is needed.

There are plenty of MG4 owners here, both with and without undertray issues. However, it is important that both groups respond to the poll!

Because of the limited options of the internal poll this one is placed elsewhere. Click on the link below:
Undertray Poll (closed!)

At the end of the survey, ignore the dutch page where they ask you for an email adress. They just ask you to create your own account for making your own surveys.

NMLGSAN, sorry to have missed the poll (obvs would have responded); have been a bit busy doing a re-roofing job (my house) and the whether hasn't exactly been user-friendly this summer. Anyway, seems many folk either don't have the problem, or don't care - a shame. The undertray bulge is very definitely - and equally obviously - not 'an acceptable aspect of the design', but if so few owners care about it then it's going to be hard to get MG to 'own' their design issue. On the other hand, with so few complainants, it would be cheap for them to fix...
I'd wager that the worst-affected cars would lose a few (something around 2 to 4) miles off their wltp/whichever rated range, and driving through pan-depth water would quickly and substantially rearrange the whole undertray. Not to mention all the road crap that will now get scooped into the motor bay. ( The picture of the dirt counterflow was from our car, but like others, I too suspect it's origins are more likely to be other than the 'scoop', but would love to see the aerodynamic model of it...)
What happens now? Our second service comes up soon,
; I'm taking it to the main dealer and will let them know my thoughts in no uncertain terms. So that'll get a result.
Lol.
Good luck and thanks for the effort; sorry again to have missed all the action.

 

[turntoport]

P.s: why the concern over the dirty mark: it shows a very clearly defined air pressure bleed from inside the aerodynamic fairing (body) and is obviously a counterflow, indicating a significant drag increase, i.e. energy loss. An F1 aero's dude would be sacked for this; with our mass-cheap cars, well, it's just a n other 'too expensive to bother to fix (do properly) aspect of design. Compared to a typical SUV, however...