How does the type of engine effect crash test performance.

[st4]

A safety related thread this one but I am genuinely curious to find out how certain models in a range would perform in a crash.

Lets take the W211 E class saloon as an example. The NCAP test was done on an E220cdi Elegance, see it here

How would an I6 engined E320cdi fare in that test with the extra mass upfront. It was discussed on the other forum that one advantage of the new V6 diesels MB are using is that they are more compact and therefore "fit" around the crumple zones more effectively.

Would a lighter E200k fare worse as there is less mass upfront (and less metal to take the energy out of the crash in the form of an engine).

Is the effect of the engine so marginal its not worth discussing or is this something to think about?

 

[Dieselman]

It's not the mass of the engine but the space it occupies, smaller is better as it allows the car to crumple without hitting the engine and sending it backwards through the firewall.
This is why longitudinal mounted is generally better than transverse.

 

[st4]

It's not the mass of the engine but the space it occupies, smaller is better as it allows the car to crumple without hitting the engine and sending it backwards through the firewall.
This is why longitudinal mounted is generally better than transverse.

That explains the V6 vs I6 CDi issue that was been touted on the other thread. Would then the I6 E320cdi maybe perform only a a 4* standard in the test than the I4 E220cdi. Could it be said at all that people driving a particular model of car who are under the impression its a 5* NCAP performer might actually not be?

I had an I6 engined X5 then a V8 engined one. Looking into the bay the V8 was more compact so that car in a front on collision would perform better in an accident.

 

[Dieselman]

The engine wouldn't drop a car a star and there is a good argument that says an I6 is good because it doesn't occupy the same width as a V engine so the offset crash will generally miss the engine altogeter with an in-line engine, whereas a V would hit and get in the way of the bending chassis rails.
The last star is mainly small add on items, not directly related to the frontal test.
In reality it wouldn't matter as all MB cars are designed to submarine the engine and gearbox in the event of a heavy frontal.

The car that had (maybe still has) the highest score for frontal collision resistance is a transverse mount FWD car, so..

 

[timskemp]

Pedestrian safety will be affected by some engines being closer to the bonnet.

 

[Dieselman]

Pedestrian safety will be affected by some engines being closer to the bonnet.

Most cars are terrible for pedestrian safety, including the E class. Strangely the same manufacturer as mentioned scoring the highest frontal crash test score also scores the only high scores for pedestrian safety.

interesting..

 

[Uberwagon]

Most cars are terrible for pedestrian safety, including the E class. Strangely the same manufacturer as mentioned scoring the highest frontal crash test score also scores the only high scores for pedestrian safety.

interesting..

That's just not true, my wiper has no sharp edges so the peasants wont be hurt as I wipe them off the screen.

Dave!

 

[wemorgan]

Lets take the W211 E class saloon as an example. The NCAP test was done on an E220cdi Elegance, see it here

That test was for a LHD vehicle, so it would be difficult to say how a RHD would fare. It is often seen that cars are optimised for the front EuroNCAP LHD test, with engine ancillaries packaged on the RH side. So therefore under a front RHD EuroNCAP test the car would have a shorter crumple zone and give the occupants a higher deceleration pulse.

It's not the mass of the engine but the space it occupies, smaller is better as it allows the car to crumple without hitting the engine and sending it backwards through the firewall.
This is why longitudinal mounted is generally better than transverse.

All cars, LHD & RHD, under a front EuroNCAP test will contact the engine, regardless of configuration. The crucial package space that is required is length rather than width. This is roughly seen in large family cars of the late 90's that were not so much designed for safety, where transversed engined cars perform slightly better than longitudinal engined cars. Though this assessment is very crude since it's not fair to compare different engines in different cars.

Could it be said at all that people driving a particular model of car who are under the impression its a 5* NCAP performer might actually not be?

Yes exactly. Only buying exactly the same car as tested will ensure you know what star rating your car is.

I had an I6 engined X5 then a V8 engined one. Looking into the bay the V8 was more compact so that car in a front on collision would perform better in an accident.

Well only if you knew what type of crash you were hypothetically going to have. I presume the V8 is heavier, therefore in a front crash you have more energy to absorb, which may fit in nicely with the V8 engine being shorter than a I6. In a side crash it works the other way. Heavier cars tend to be easier to design for safety than light cars, assuming equal sized cars.

Taking the debate one step further, it's also worth knowing that the crash test dummies are 50th percentile in size and mass. So again, only an average sized healthy man in the same car as EuroNCAP tested, will know of his car's safety rating. If you're any shorter/taller/lighter/heavier then you can only guess at your revised rating.

All in all, your best bet is to drive safely and hope you never crash to find our how safe your car is.

 

[Bobby Dazzler]

Good thread.

Like fuel tests, crash tests don't really reflect reality. They're a series of repeatable and controlled tests to ensure consistency and parity between tests and vehicles.

As has been mentioned, manufacturers realise how important consumers consider safety these days, and as such engineer their cars to perform well in the tests.

It doesn't necessarily mean that a 5* car will be safer in a real accident than a 4* car, just that it performs better in the standard tests.

That said, I would still rather drive a car with the maximum rating than one with a relatively lower rating. A car engineered with safety at the top of the list of priorities is likely to be a better bet than one which hasn't.

So shall we start the old debate of which would you rather be a passenger in should a collision occur between a 3* SUV and a 5* supermini!?

 

[Dieselman]

So shall we start the old debate of which would you rather be a passenger in should a collision occur between a 3* SUV and a 5* supermini!?

Ok. I'll go first. Here's mine.

http://upload.wikimedia.org/wikipedia/commons/a/af/Rusting_tank_at_the_Highway_of_Death_in_Iraq.jpg

 

[st4]

Good thread.

So shall we start the old debate of which would you rather be a passenger in should a collision occur between a 3* SUV and a 5* supermini!?

Nah, I just wanted to discuss the merits/cons of different engines in the same range of cars and see whether NCAP ratings could actually vary model by model.

The 4* SUV (Audi Q7) vs Fiat 500 was an interesting thread, and I wondered how the Q7 would have fared in the NCAP test if it had been either a 4.2TDi or a 4.2 FSI (both V8 engines). I also wonder whether this would have impacted on the Q7 vs Fiat 500 example that you were alluding too.

I never really considered the RHD vs LHD, who thinks there should be a NCAP test for RHD models.

 

[grober]

I was thinking the same thing myself not long ago. http://mbclub.co.uk/forums/showthread.php?t=30514&highlight=euro+ncap
Just goes to show the NCAP ratings are merely a guide ( though quite a good one) to the performance of any particular vehicle in a crash. The issue which bothers me is what part corrosion plays in the structural integrity of an older car and also the working efficiency of the safety systems after several years. I havn't heard of any recommended replacement of airbags or belt tensioners by manufacturers after say 10 years. Have these items got a projected lifespan I wonder??

 

[st4]

Thanks Grober

Personally I do not entirely like the NCAP approach to car safety. Consumers are encouraged to believe a 5-star rating is the best they can get. However, car test results are divided into many different classes. A 5-star rating for a supermini and a full-size saloon are not the same.


http://www.safecarguide.com/exp/deathrate/idx.htm

I am not so sure this is true, I thought that a rating >30 meant 5*. These were points that were earnt on absolute merit, i.e. a Fiat 500 performs better in the frontal offset test than a BMW E60 5 series.

 

[Dieselman]

I am not so sure this is true, I thought that a rating >30 meant 5*. These were points that were earnt on absolute merit, i.e. a Fiat 500 performs better in the frontal offset test than a BMW E60 5 series.

I think you are right as each car is tested at 40mph into a barrier and hte damage tot eh occupants is then measured and scored accordingly.

The results are not determined by vehicle damage, but occupant damage.

A car scoring 14 in a frontal test is better than one scoring 11, say.

http://www.euroncap.com/tests/frontimpact.aspx


Ahh. Having said that.
It simulates one car having a frontal impact with another car of similar mass.

 

[st4]

I think you are rigt as each car is tested at 40mph into a barrier and hte damage tot eh occupants is then measured and scored accordingly.

The results are not determined by vehicle damage, but occupant damage.

A car scoring 14 in a frontal test is better than one scoring 11, say.

http://www.euroncap.com/tests/frontimpact.aspx

Thats how I see it, and its absolute.

eg if a Supermini and large saloon were put thru the test, and both got scores of 28, both cars would be awarded a 4* rating. The supermini would not be awarded a 5* rating as i did well for its size.

With NCAP tests I look @ the Diagrams in particular to see which has done best

Audi A6

W211

Fiat 500

All 5* cars in their own right but if its simulated with cars of similar mass then I'll be holding onto that 211 for quite some time, all 2 tons of it....

 

[Dieselman]

Pah, forget those. You want one of these..

C5

 

[st4]

Pah, forget those. You want one of these..

C5

I'll trump you with this

 

[Dieselman]

Nope. C5 wins due to no chest injury. It's the highest scoring car ever tested by Ncap, and the C6 is the most pedestrian friendly car ever tested also.

 

[MBManInKen]

All 5* cars in their own right

NCAP is all good and well if you buy a middle segment car, but they have no test results for the top segments. Thus, no data for the s-class. Neither do the Americans.

 

[st4]

Nope. C5 wins due to no chest injury. It's the highest scoring car ever tested by Ncap, and the C6 is the most pedestrian friendly car ever tested also.

I knew you'd say that, but look @ the Nissans side driver impact protection vs the C5's. Nissan has 37 points C5 has 36.