Seriously what IS the point of all the plastic in the engine bay?

There must be some reason... otherwise what is going to stop anyone and everyone from ripping it out.

Sorry I don't want my hot rotary cracking a bunch of plastic and slicing up my pulleys....

Can anyone say unneccesary heatsoak and weight?

And what about working on it? Who wants to have to remove a second hood so to speak just to get to it.

Oh wait now it all makes sense, removing the plastic = 1 hour of labor. Dealer repair cost inflation!

Everything else about the rx8 seems so smart, so hopefully there is some point to this madness... but I can't think of any. Sounds like engineered rice to me, who cares if your engine bay looks good? Personally I like seeing a chaotic engine bay with tubes and the real deal glaring out at you screaming I MAKE POWER!!!!!

IMO an engine bay should look like this http://dh3.doggus.com/~nef/rx7/enginebay.jpg

 

It seems to be the style now. Take a look at a lot of other new cars coming out, and you'll see the same thing.

I completely dislike it too.

---jps

 

Yea but bleh, it should be an option...

Does anyone have any info on it like weight, how it comes off ect, if its purely asthetical or does it actually have form to function ect ect...

 

The only reason I can think of is that they do that so the parts inside the engine don't get covered with dirt and crud. Working on an engine covered in dirt and crud isn't very fun, and most people don't bother to clean their engine bays. At least be happy that you can see some metal. I saw the engine bay of a Z06, and it was ALL plastic, no metal to be seen anywhere.

As for weight, I can't imagine that it would weigh more than a few pounds. It's just plastic, after all.

 

It's just for appearance sake. In a time where "bigger is better" as far as displacement goes because of the ongoing horsepower war... I think the Renesis won't sell if they open the hood and show people how small it is.. people will be thinking bad things and that translates into bad sales.

I personally like the cover, but either way I don't care. With it or not, it's my next car.

 

90% of all prospective buyers of the rx8 will probably know more about it than to buy it based on engine size. But you make a good point.

 

Actually i thinks it there to drown out a lot of engine noice, also the side exaust goes a lot closer to the top of the enigne and there will be a lot more heat disipation there so the plastic may be there to keep the paint finsh from cracking.

 

Do you really think that a couple of panels like that are going to keep dirt and muck away from the engine? Are you sure about that?

---jps

 

Mazda has never been one to follow the crowd, the rotary engine is a great example of this. I am kind of mad that they are starting now.

 

You have to think about the possiblity for Thermal efficiency with the plastic covers. They may be there to control the temps in specific engine zones. I seem to remember from somewhere that rotaries do not have the best thermal efficiency. Because of the seperate combustion chamber and exhaust chamber, the intake chamber is alot colder, thus requiring(not requiring, but for better engineering) plastic housing to keep the temp uniform through out the block. this does not mean that the intake mass air flow is warmer it just means that the metal surrounding it is kept at a non-differential temp(with respect to the exhaust/combustion chamber).
We all know about thermal expansion an how it could devistate a rotary engine if the rotor housing warps. Bottom line, the plastics possibly act as heat shields/ insulators. This post could be alot longer.....

 

There may, or may not be a rationale for this. But either way, we better learn to deal with it because that's the way the car is coming.

I for one like it, but to each his own

 

So you think that that plastic is going to be able to handle heat better than the aluminum or steel hood?

---jps

 

perhaps the plasics have an iner duct work witha small fan in side to blow the heat in another direction, and plastic is a better insolater then metal.

 

Plastics are becoming very advanced in their chemistry and performance. Check out a Honda Harmony pushmower sometime. When I bought mine, they had mowers with both a plastic and a metal housing for the engine and blade housings. The plastic one is 1) MUCH quieter, 2) MUCH cooler, and 3) MUCH stronger. You can literally hold your hand on the engine cover after using it for an hour. Try doing that with a metal housing. I can carry on a conversation without raising my voice while the engine is running and blades are turning - it makes a great sound insulator. Finally, the salesman showed me how strong it was by hitting it with a sledgehammer - no dent or mark whatsoever.

The sad thing is that he told me it wasn't a great seller because most people didn't want a 'plastic' lawnmower - they wanted a sturdy metal one

So, 'plastic' under the hood doesn't bother me a bit. The only concern I have is how easy it will be to do routine maintenance.

 

Tubes?! Yikes, never heard of valves in a car before. That would be interesting, though - a quartet of glowing, singing EL34s under the hood :D Heh heh. What did you actually mean by tubes?

 

Yes, I am aware that there are some plastics that are capable of handling a good amount of heat. But covering the whole engine like that as opposed to one or two heat shields for a couple of hot spots doesn't make sense (unless it's for looks). Enclosing an area where you want heat to escape doesn't make sense (unless it's for looks). Putting in plastic covers and a couple of fans and ducting, when you already have a big-*** fan behind the radiator moving all sorts of air around doesn't make much sense either (even if the plastic could handle it).

And just because plastics are used on the mower doesn't mean it's the main reason why your lawnmower runs cooler/quieter either.

---jps

 

i emailed people at mazda asking them about the purpose of the plastic. i'll let you know what response i get.

 

Did they ever answer?

 

well i have confirmation on this on from some place can't quite remeber where it was so long ago, the engine cover is there to direct the heat of the engine out though the brake cooling vents, see for yourself without the cover the brake duct vents are acutally alot cooler then with the engine cover on.

 

Some of it is for heat issues like the battery cover and ecu cover, the engine cover probably helps heat go out through the openings behind the front wheels.

Personally I think it would look bad *** if you opened the hood and all the plastic covers were carbon fibre.

 

man this is an old thread, but I know they make the main engine cover out of CF.

 

what polak said. but its more of that 2 way thinking or "reverse" thinking as i call it from time to time. it serves to purposes - directs airflow for cooling and looks good(subjective yes) which came first?

 

We're in summer re-runs. There are a bunch of oldies being resurrected lately.

 

Do a search...I brought this up a month or two ago. It was to redirect airflow.

 

this thread started in 2002