takahashi

Some one comes to term and actually measure the temp of the vented hood and normal hood. The Re Amemiya wet carbon hood was used

Labrat stop your comment NOW!

This are the points they are recording (no explanation required)



These are the results (I have attached some easy translation)
Download here

Enjoy

By the way, it is a 25 degree day in Japan and full throttle can go up to 130 in oil temp and 91 degree in water temp.

RENESIS IS HOT!!!!

Gibbo

OK now what does all that mean in terms of how much quicker I can get through maccas drive through? :D

takahashi

It will mean a cooler engine on the way to get your big mac at full throttle. But only a cooler engine BAY when you are waiting for your big mac in line

RXP33D

You call that purposeful vented hood...?

I think not!

RXP33D

http://givemealook.com/ipw-web/galle...um507/100_6118

takahashi

Love that hood LOL :D

I am sure it will work 2 as good and 7ps gain :p

labrat

All I am saying Taka is that it is unwise to replace a critical body component (the hood) which has been specifically designed to minimize trauma to pedestrians in case of impact. The book we received about development of the RX-8 described the hood design in detail, and why it was designed that way. As a pathologist who sees many road trauma victims, you cannot help but applaud such a feature. If you have data which demonstrates that this plastic hood has been tested and produces the same or superior safety outcomes as the stock hood, then tell us about it. OK, the temperature under the hood may be lower, but how do you equate such an advantage against the possibility that the replacement may cause more accident trauma (including head injuries)?

Taka, please accept that I don't mean to lecture you, but being a health professional places you in a position where your every utterance on just about any subject which may impact on human health or even life has to be carefully considered. In saying that it doesn't excuse those of us who aren't in the health industry from not thinking about safety first. In this country, cars are the most readily obtainable deadly weapon, and their effect is demonstrated every day.

takahashi

ehhh.... you lecture is very sound.

But I will be out of business without those idiots killing people :D
Yes more work for me

timbo

taka, you're awefully concerned about engine temps suddenly. Care to elaborate? Seems to me Mazda designed the 8 following extensive previous experience with rotaries (where cooling, especially on FI versions, was a problem --- yet I've not seen much on this in relation (NA) 8's)...have you had a problem?

takahashi

Not suddenly, I always says Renesis is still too hot. That is why I have a 2nd oil cooler for the track days. Mazda Japan (yes the people who design the RX-8) enforced owners to have radiator upgrade and oil cooler addition before racing in their event. And their race only goes for 15 laps!

Your mazda rotary OIL start to degrade at 130 degree C. If only a little fang in Japan's spring will get the oil temp up to 130. What will happen after10 laps in a race track?

I am sure you don't want to change engine oil everytime you do a fang on a quiet road.

If the engine temp is that unsatisfactory in NA mode, what will happen with a bolt on FI?

That is all

Zephyr

if u are so worried about the health of pedestrians... why not just change to a primus instead, im sure the pedestrians will be much safer that way :p

EZZY

quick question....
who keeps their engine cover on

Gibbo

I keep it on.......the garage wall

Revolver

Okay, I'll play the dummy - I keep it on. Care to elaborate on the pros and cons??

Zephyr

the cover suppose to direct the hot air to the side vents, all it does.... apart from keeping the engines nice and tidy...

but i think it makes the engine bay look like as it's made up of cheap plastic
and i have mine off btw, coz i have the ms tower bar

takahashi

same here! Not regret. The MS tower bar is 10X better and IT IS FUNCTIONAL FOR SURE :D LOL

DMRH

Eric is it.......??

I know plenty of RX-8 guys that leave it in the garage as it trap too much heat & makes the engine bay look tacky

EZZY

yes David....
just a quick question for those who are worrying about the un-vented factory bonnet and engine bay temp.
i think my engine cover is either on the top of my tool table, kitchen corner or the storage room at the workshop :o

timbo

But there's been no reports (that I can find) of temperature-related failures...

And if Mazda designed the engine cover to deflect heat out the side vents, might you not risk the new heat flow (without the cover) progressively damaging the bonnet -- esp the paint finish -- over time??

I have certainly noticed the heat flowing from the side vents when walking around the car after a run.

Gomez

Did you notice, Taka, that the congested driving temps of the oil and coolant were EXACTLY the same with either bonnet. This shows that the Mazda design guys have engineered the car correctly for everyday conditions. Whilst the underbonnet temps were up with the std bonnet, the radiator and oil cooler(s) did their job.

Underbonnet temps are not all that critical unless you're racing and trying to grab every last hp. This car has no return line to the fuel tank, so fuel heating is not such a critical hp issue either.

Gomez.

Gomez

My engine cover remains on the car......

BVD

Don't panic chaps! 91c is NOT hot for the water in a car engine.

Depending on the age of a car, it will use a combination of systems (including thermostats, chokes, fixed or electric fans, management computers, etc.) to get it up to an optimum working temperature.

And this does NOT mean as cold as you can practically get it. For a variety of reasons engines run best when running what sounds fairly hot to us. A typical operating temperature would be in the 95C general area.

And just because it runs at 91C when the outside temp is 25c doesn't mean that it will run 15c hotter when it's 40c outside. It will just require the management system to make adjustments to keep it within the desired range.

We think 91c sounds hot because we're used to water boiling at 100c. But remember that the coolant in you car will NOT boil at 100c, if it's working properly because:

a) It's under pressure (yes, that's why your car has a pressure cap on the cooling system. The more pressure the higher the boiling point. You can't make a cup of tea at the top of Mt Everest because the water starts boiling at much too low a temperature to make a decent cuppa. )

b) The "coolant" we use (known as antifreeze in some countries) does several jobs - it contains corrosion inhibitors, but it also contains glycol which both lowers the freezing point of the mixture, and raises the boiling point. )

So at 91C your car is doing just FINE - in fact it might appreciate a tad more heat. :D

timbo

That's what I thought. What and where is the problem we're trying to solve here?

takahashi

Download this clip

This is the Best Motoring Video about cars racing 20 laps in the heat (35 degree) Please notice how hot the RENESIS is compare with the Honda

http://www.step-hen.com/rx8/files/heatrace.WMV

BVD

So what!

Admit it Taka, you are just looking for an excuse to buy another piece of boy racer kit to flash up your car. :p

No offence meant Taka, but you're neither a mechanical engineer nor a chemical engineer and you appear to be grasping at straws here in order to justify another toy.

Don't you think that the people who make these things are going to find some conditions that allegedly "prove" that their product is better - regardless of how limted the test conditions were, and regardless of whether the alleged difference really is necessary or better anyway?

If people want to put spoilers, body kits, loud exhausts, racy bonnets, and fancy decorations on their cars then I say good luck to them - each to his own. Often they improve the fun that the driver gets out of the car in some way, and that's great.

Just don't expect me to take it too seriously. :p

Cheers, Chris

( and yes, I did put loud exahaust and other things on my car when I was a kid, and yes I AM a motor engineer, of over 35 years standing. Just a spoilsport old fart I guess. :D )