It's primary purpose is to shield the heat radiating from the engine, not to block the hot air.

So what is the grey felt lining for?

S

WOW, it's easy to just drop something like that.
What is so ignorant about this?
Perhaps you would you like to indulge us with your view and understanding of the correct purpose of the cover? Something that is based on the pure facts ad not speculation please?
Or are you going to counter the fact that the hit energy can be transmitted via other means than matter to matter?

But then again, your opinion in this forums is aways sided with the opinion of the majority. I have never seen you to post anything more that a smirky comment, that has something similar in content. It is either that, or you just sit there quietly with your mouth shut, pretending to look smart.

Let's hear the voice of the genius

Isn't the felt lining a fire retardant material?

I'm not defending anyone but if you're going to ask anyone for proof you should be prepared yourself. Where is the flaking, peeling, faded, whatever hood? And further more you'll have to prove that it's because the engine cover was off, not oxidation, abuse, or any other variable.

Everyone gets so defensive and hot headed for nothing but a little testosterone rush. If you're wrong you're wrong. If you can't prove something and believe it anyway, good for you.

Edit: And yes the felt is for heat but more so noise. The cover does nothing. Ok, that's a lie, it looks nice to some people.

Ze Goggles - Zey do NOTHING....!!

Yep, that was actually my other thought.
It is there just to look pretty.
But it will provide an additional level of shielding from heat produced by the engine.

I've seen plenty of those (Not on the 8, 8s are farely new), and in most cases the cars I've sen with peeling paint didn't have the covers.

I don't have to prove anything.
I stated what I reasonably believe to be true. Everyone is entitled to think differently.


How was I proven wrong?
I was called ignorant without any explanation or reason.
That was just rude. If I am wrong, offer me a reasonable explanation why, i am wrong. I nave no problem accepting other people opinions.
We had disagreements with MM, CRH, Mysql before but never at any point we called each other ignorant or anything like that. we argued and defended out opinions, ad it was informational. Ind in some cases I was wrong, and I admitted it without any problems.

And there you go yourself saying what i said in my original post...

Pretty poor engineering materials choice to use that horrible waxy-black plastic as a heat shield.......

S

Uh... your reading comprehension skills might be worse than mine. Nobody said you were wrong. Likewise, nobody said you were right. I'm signing out right... here.

Comprehension skills... Not wrong, not right... So what the f*** are you saying then? Do you even have a point, or you just sitting there barking at shadows?

Some conflict mediator you are :lol2:

Consider your responses more carefully next time, and people will have no trouble comprehending. :spank:


You gotta love it! Come up with something that's beneficial to others and in return they call you at first a pussy, then ignorant, and on top of that it turns out that my comprehension skills are not there. WTF? :Eyecrazy:

People don't like having their preconceived notions challenged. Get used to it.

Some got real pissed off because it would make them look stupid to drop $800 on a CF vented hood, using an excuse that it provides improved cooling. Now they'll just have to do it for rice. :)

Im open to logical discussions.

One more thing to consider is that under the car is not the low pressure zone, under the car is the high pressure zone. So, naturally air will be wicked up to the lower pressure faster moving air going over the top of the body of the car. Thats just common sense. Thats how airplanes fly, and after all a car is merely a wing shape that never leaves the ground.

airplanes fly because they have high pressure on the bottom of the wing because the air has no obstructions as it passes under the wing. But since the top of the wing has a large bump on it air wants to move more quickly over this bump to exit at the same rtime as the air going under the car. As the air moves quickly though space it spreads out and becomes less dense, this is what is called a low pressure system, and this is what the entire top of the car is in comparison to the underside of the car. Air moves from high pressure to low pressure, never the other way around.

Now in airplanes and some very fast cars, the high pressure under the car becomes so great that it can lift the thing off the ground, almost like magic. :)

Therefore, air wants to move out the hood toward the top of the car. But though clever ducting and blockoffs we channel this under the car to cool the catalytic converter and tranny.

but generally air wants to move out the hood, and generally we like cool engines and transmissions, which is why the engine cover is in place, to divert air trying to excape the hood down to cool the headers and the coils.

but seriously, if you want to prove it, just buy some dry ice or a smoke bomb, put them in your undertray in front of the radiator and see where the smoke comes out with/without spacers.

Thank You! Finally someone who understands basic aerodynamics!!:banghead:

One thing you guys didn't mention when you do this mod is that you need to put screws or something back in the holes to stop the plastic cowl thingy coming loose .....

I might have to test this mod at the track next time I go .

airplanes and race cars go real fast. in 45mph traffic and idling in slow traffic--airflow is a different animal.
When I come off a track session the engine bay temp is very mild--hell the cooling fans dont even come on when i park it.
When I drive home from work with the a/c on etc, the cooling fans come on when I park and if you lift the hood--- it is hot--- real hot, surface temp on coil packs at 160-170F.
So-i did this little mod and repeated a drive home on a 95f day in georgia. Surface temps on my coil pack was 150-160F . Thats enough for me, Aint worried about the small part of paint on the hood that MAY get a little warmer---hell my dash gets 150F!
This is one mod I say "Good job" this one works!
olddragger

WTF ! are you kidding me ? What sort of old lady drivers track are you on ? :)

come--- on check us out anytime. We are at Road Atlanta running laps at around 1:50s, Roebling Road lapping at 1:26 or so. Maybe our gearing is a little better, keeping the rpms down? Ya think? Coolant temps on track are around 220F, oil temps 220 to 230F. Even on a 100f ambient day.
you are welcome to join us anytime.
olddragger

and to add coolant temps are down to below 200F after the cool down lap.So no fans on in the pits.
OD

I just did this mod in a way that takes care of this concern. LINK

he he - sorry for the wind up OD . 220 is still pretty hot though - your fans would definately be on . I'll try doing a cool down lap properly next time i'm out rather than just the last 1/2 mile .

LoL --np man---I know what ya mean as far as it's hard to do a full cool down lap:)
OD

the air going over the top of the wing actually leaves the wing before the air going under. The 'it exits at the same time" is a myth, but one that makes it intuitive as to why the air speeds up.

The other problem with that theory is when you apply it to thin wings.

Referring to the Mercedes CLR Le Mans flip? That was because the high rear downforce and the way/amount of front downforce is generated is highly pitch sensitive. A few degrees change in rake (aka angle of attack) to the oncoming air turns the front from a huge downforce generator to a lift generator, but the rear wing still forces down, causing spin, which further increases AOA which further increases lift at the front, and so on, feeding back into itself till separation.

The front of the car is a high pressure zone, ditto the underbonnet region - so yes, it'll want to move to a lower pressure region, but not everywhere on the top of the car is lower pressure, thats why you don't place vents designed for high speed cooling near the base of the windscreen.

it is a water cooled engine, if you want to keep it running cooler then you cool the coolant. Cooling the surface of the engine really makes zero difference to the engines actual operation. (Why do you want to cool your exhaust headers? usually you heat wrap/coat them to keep te heat in)

The engine cover is a pretty piece of trim, but it does no work in directing air - the underboonet air is not flowing nicely, it is all turbulence in there - the stock bonnet would perform the same role in directing air as the engine cover. The engine cover is there because without it that area looks like ass, same reason some ugly V8s have them, same reason Ferraris, Veyrons and Supras (OK, I'm biased in that regard ;) ) don't have engine covers like that (just trim pieces to cover our ugly plugs/coilpacks)

If all you want is to keep the underbonnet temps down during slow/regular driving or when the car is stopped, then any topside vents would help.

Here's a proper explanation of lift over an airfoil and the typical theories used to describe it.

http://travel.howstuffworks.com/airplane5.htm

I agree the most effective ducting would be directed at removing the air from behind the radiator ala lotus Elise or Ferrari F50. Having a duct and exit vent from right behind the radiator and ditto for the oil coolers.

So what about washing your car or intense rain after doing this mod? Are you allowing water to get into your engine bay?

Of course you could do this like expo1, where you can screw on and screw off the bumpers. Note- Also black bumpers would look better.

https://www.rx8club.com/attachment.p...5&d=1186341710

I have the same question as sosonic...does water ENTER the engine bay after you do this mod?

For the past couple of days I've been through some real heavy, FL type of rain.
I mean the kind there you can barely see the car in front of you doing 20 MPH.
So I was observing the water as I was curious myself.

There is no issue of water getting in the engine compartment.
The hood edge hangs over the gutter a little. Unless you are going to intentionally pour water into there with a hose or something,
it just drops down into gutter at the base of the windshield.

If there is some moisture, that gets there, it'll evaporate quickly given the amount of hit produced by the running engine.

While in a stand still, water just don't get there.

Where did you buy the plastic blocks from? I went to home depot looking for spacers and they just got confused...

In the isle with the Screws & nails ( I think ) It was in the section with the plastic feet you put under furniture. I painted them Black by the way. They only look that bright when you take a flash photo.

I can see rain not being that big of an issue for this mod, but what about the CAR WASH?

Also, if you do the mod (the expo1 way), I would think thumb screws with the rubber bumpers would be best. So at least its easy to take of the rubber bumpers or put them back on.

It's not a problem on my 8. I use a pressure washer when I do it myself and/or take it to a local car wash once per week. Even when directing the pressure washer to that area, limited water gets in (a little driping down the firewall). I check it when I was at the car wash and there was no water in the engine compartment save water on body lip.

Water in your engine bay is meaningless, anyway.
I pressure wash my engine bay all the time.
If you live in a place that gets rain, check out how much goes up into the engine compartment.

if a quarter inch gap produces a 10 degree temp drop, i bet removing the hood would get your temps down to about room temperature... :lol2:

its so nice that we have an air cooled engine instead of a water cooled engine :rolleyes:

Well, not only is that technically true (water is just a transfer medium - air does all the cooling), but it is also true in that the Renesis does have more in common with VW and Porsche when it comes to oil/air as a cooling method.
Rotary engines are, as would be labeled by those other marques, oil-cooled.

BTW - removing the hood does work really well. I did that a few months back when I was shooting some paint.

long known that a true hood vent (up front like evo) is the most efficent cooling mod for the 8
OD

I decided to try the mod as its dirt cheap and I have a scanguage 2 to help with my opinion. I did it the expo1 way, but used thumb screws to hold down the rubber bumpers.

I noticed that my average temps. appear to go down from ~185 F (which is already good) to ~182 F. Including longers "dips" at 179 F. I also have the Mazsport cooling mod (which works very well)... It does appear to make a few degrees different, but I do acknowledge this was not a controlled test and is more observation.

My opinion is that this mod would be particularly effective in traffic in helping the engine stay cool. Hot air does flow out of the gap, when your car is not moving.

I think the other aspect of this debate would be what does this mod do for you at high speeds for extended periods of time.

It seems this part is also partially an aerodynamics question. But the FI guys appear to be reporting improvement in the duration they can stay in boost.

Overall, this is one of the quick and cheap mods that at least should not hurt anything and at best you are getting a slightly cooler running car.

This mod does not take away from say using Redline water wetter and more water in your coolant mix. You could go from 65% water and 35% coolant to 70%+ water and a mix of anti-freeze and Reline water wetter. That would help cool your engine too. The point is that the mod does not take anything away or stop you from doing other things to cool your engine. They all can work together.

which is within the error band of the ECT sensor



except permanently deform your hood, make you always have HVAC system on recirc, and risk on day being killed by exhaust fumes if you ever get an exhaust leak under the hood....

if you wish to ignore the facts of:

a) the porsche block, much like your lawnmower engine, was designed to be air cooled while the Renesis is not which has water cooling jackets in the block

and

b) the water system of our cars rejects 2/3 of the heat while the oil system rejects 1/3 of the heat due to the fact that water is 2x better then oil at removing heat, the water system physically flows more volume then the oil system, and the heat exchanger surface area for the water is about 4x bigger then the oil


then yea, the rotary engine is very similar to the air cooled porsche/VW engines

rot0r
Why do you continue to resist the fact that this works literally to the point where you make yourself look sort of stupid?

Take a big breath before you produce another one of your outbursts, and please note that I did not call you stupid, I said you make yourself look that way

It all just sounds ridiculous coming from someone who posted this:
Don't you think?

ECT sensors are usually 2% accurate... 2% of 200 degrees is 4 degrees... if you can't manage to get outside of the error band, you prove nothing

for the tein installation, the weather stripping is only removed at the very end of the hood which is not where the fresh air intake is and the hood is lifted by the hinges and not being buldged up by spacers... and the lifted area doesn't do shit for airflow

but go ahead and try to prove a point :beer05:

I don't have to prove a point. My point is proven by probably dozens of people who had done this by now, and reported improvements. You on the other hand are trying to swim your way up the waterfall.

I myself have driven with this for a month already, and my car does run cooler. And when I come out of boost it does recover much faster.
As for the recirculation - I recirculate the air 100% of the time by choice, not because I have to. The air is cooler that way if you haven't noticed.

You are going a bit too far with your busted header argument. Don't you think you'd smell it first before you suffocate? I'd probably hear it and feel it due to lost boost too. So lighten up. ;)


:beer05:

well, last time i checked your "proof" included an experiment where you had no idea of the status of either of the radiator fans, only "you know how your engine runs".... gee, do you think a radiator fan kicking in could result in a drop of temperature?!?!

you never even bothered to figure out where the air was going like others (including myself) did... but thats right, you don't need to prove anything works

Why should I? You are really running out of arguments here... :rolleyes:
Do you need a proof that UP is in fact UP or DOWN is DOWN? Sure you can argue that too, but the way I see it it is what it is. Moving on. Life is simpler that way.

The "error" band on the ECT would be relative, wouldn't it?
Or are you saying that it will just wander up and down 4°F willy-nilly?
I'm sure you are not saying the latter.
So, if it was off by 4°F at the onset of the experiment, it will still be off by 4°F at the end of the experiment, so the delta is still going to be legit.
If you do mean that it is off by 4°F randomly, why would the entire error band get used up in a 15°F span of a sensor that is designed to read temperatures from 120°F to almost 300°F relatively accurately?

I think you can safely discount that argument.

I'm not doubting that this works but can anyone give me a theory as to WHY it works ?
I'm just thinking about how heat is taken away from the engine and I'm pretty sure that very little heat exchange takes place by hot air flowing over the engine itself. The only logical explanation seems to be that more air flows through the radiator as a result of the mod - but how ?

We are simply giving the air that goes through the radiator more choices for an exit.
Its like putting on a more free-flowing exhaust system.

Yes, we relief the under-hood pressure, by letting the air out, so fresh air can come in. And the only place for it to come in through is the radiator.

Daamn MM, these two babes with glasses look fine.

yeh -something about the glasses does it . Can't quite put my finger on it ......

I'd definitely put my finger on it...... :rofl:

I'm not saying what I did with my finger.

You could also cut up your OEM hood and install a bit of fiberglass (so it doesn't look like ass):

http://www.grounddynamics.com/Merchant/UNISTDI.JPG

then some paint...