sor-hoa

Does anybody tried to have a carbon fiber hood on the GLK250?
Car is nice but sort of heavy. Is not very good on acceleration, either on breaks ranges too. Engine is great, but if the car would be lighter on the body, she would be a real kicker. I am thinking to get carbon fiber hood. Also carbon fiber front and back seats(the rear back is really heavy). I searched everywhere, but not such thing yet. For the seats will be hard because of the multiple functions and motors.

Powerband

A carbon fiber hood is certainly lighter. But the GLK250 is a 4300 pound vehicle; what percentage of weight shaving do you think this change will make, and if it even will affect the performance to any meaningful degree? I wouldn't imagine the ROI on such change is that great. On a Miata, a Mini Cooper, or a Lotus, the carbon fiber hood might make sense, but it's hard to imagine this on a Mercedes GLK250 with a Diesel engine producing 369 foot-pound of torque.

sor-hoa

You're perfectly right. It will not do much, but it's a start. Thanks.

Powerband

It would be good to see how far you (or someone) can take the weight shaving, and see the functional and dynamic outcome. Good luck!

Diabolis

ROTFLMAO


Please tell me you were joking... please?

swatty

X2

MBKLUE

x2 squared (or something like that)

koalatm

You don't need to reduce weight in that area of the vehicle.

Want to make a difference? 17" forged aluminium wheels - 1 lb of rotational mass is roughly equal to losing 4 lbs elsewhere. Stock wheels on this vehicle are very heavy, you could easily lose 7-10 lbs per corner including the lower weight tires. If you've saved 10 lbs per corner that's realistically shaving off 160 lbs from the vehicle weight, in a roundabout way.

If your carbon fibre hood was say 30 lbs instead of 60 (I'm just guessing), you've saved 30 lbs.

Diabolis

While everything you wrote above about the effects of rotational mass and weight saving is 100% true, the reality in this case is that we're still talking about a 4,400 lb, 6-foot-high diesel SUV with an 8" ground clearance and the aerodynamics of a brick (not even an ML63 where you can at least stiffen up the shocks and you have 600+ hp to boot). If he was asking about reducing weight on a Mazda Miata for occasional track use, the OPs question would have been perfectly valid and quite relevant. This way you're just wasting your time by indulging him in a ridiculous and irrelevant fantasy. In other words, reducing a few pounds here and there - sprung or unsprung - from a GLK is a completely pointless exercise in futility.

And, for the record, going with 17" wheels on a GLK will indeed save him some rotational mass, but unfortunately the tire sidewall will be so high that any theoretical benefit to the handling as a result of the lower unsprung weight and rotational mass would be offset by the considerable increase in the tire's sidewall flexing (235/60-17 look like balloons - the sidewall itself would be 141 mm or over 5.5" high), and furthermore, in order to supprt the required 5,500 lb maximum gross vehicle weight, the tires themselves would have to be heavier as they would need a lot more more reinforcing (steel and nylon belts) in the sidewalls. So - in this particular case, it again wouldn't translate into anythign useful in any way. As I said, it's a completely pointless exercise in futility.

mjhawkins2346

Oh, I dunno. If the OP has the money and time this might be fun to watch. Maybe everybody learns something. I suspect you are all pretty much spot on with the marginal and expensive improvements but there could be discoveries.
How much can be safely replaced or jettisoned before the car ends up as a bad NASCAR wannabe? How much will the performance change if you can get rid of several hundred pounds (somehow). How much better is the handling with a lower unsprung weight?
I don't think any of us are better than Mercedes engineers with a whole company behind them, however there may be interesting things to learn.....

Diabolis

Well... there won't be any "discoveries" - as in everything we have been discussing has already been tried and it does work. It's just that he is talking about doing this to a GLK. Let's assume for a second that he completely strips out the interior, removes the A/C and other unnessccesary items like the stereo / NAV, airbags, replaces all glass with Lexan and what not - essentially, he makes the car look like a Dakar "special". Now, seeing as the GLK is built like a brick 5h!thouse, all that dieting will *maybe* save him 400 lbs, leaving him with a 4,000 lbs SUV powered by the same 200 hp / 370 lb ft engine, with the same city-street-tuned suspension and track width, an automatic with a torque converter and the OEM diff in the middle. Just how much do you think this will do to improve performance? It might decrease his 0-60 time from 8.0 to 7.9 seconds and allow him to corner at 0.68 g instead of the previous 0.67 (these are made up numbers - I don't know if anyone other than perhaps the MB engineers that designed it has ever attempted to measure lateral acceleration on a GLK). In other words, even with the marginal performance improvement that he achieves, (which, again, he will), it's still a marginal improvement on a rather slow, heavy and high roly-poly SUV with no sporting pretentions. It's a complete brain fart and waste of time at best, and he would be molesting what is an otherwise very decent and luxurious SUV. From a performance standpoint (which is what the OP claimed is the reasoning behing his insanely idiotic post), it makes about as much sense as putting a spoiler on a snail to see if it can go any faster.

Seeing as I have already wasted 20 minutes of my life that I'll never get back indulging someone's completely insane and ridiculous fantasy, I'll leave this to the rest of you as there are other places on the forum where I can spend my discretionary time on the interwebz dicussing something a little more relevant and useful. OP - if you are still skipping out on your medication, good luck with the project.

rmfnla

If you wanted a fast car you bought the wrong one...

MJ50

weight savings on GLK is quite meaningless...
better to just upgrade turbine, larger intercooler, ecu tune, bbk and u r done...

bugelrex

Best bang for the buck would be CHIP for the GLK250, it will most likely increase the boost at the cost of reliability/life span.

shotgun_banjo

The 250 is not meant to be a rocket. The 350 can be a rocket. I think weight reduction on the GLK will be pointless no matter what the engine is unless it is the brabus version.