Does anyone have any ideas on how easily vent the heat from the engine bay? I was thinking of vents on the hood, louver style, but figured that would look a bit out of place if it wasn't a race-only vehicle. I saw a race-only FD with a louvered hood but I figured it would look out of place on an FB's hood. One of the shop techs did mention how his friend's old Supra had these "side humps", or whatnot, on his hood with vents in them. Said it looked really good.

Has anyone else have ideas or suggestions on how to help vent the heat out of the engine bay to keep it running cooler? This could be side vents, different styles of vents/openings on the hood, etc. But, don't suggest turning the heat all the way on.

 

does your engine run really hot or something?

 

BMW M3 fender vents would probably look cool

 

No, it's always run fine, the needle just barely touches the thermo symbol. The idea actually came to me during one cold morning when going to work a few weeks ago. I drive 23 miles one way to work, takes me about 20 minutes (in the early morning). With that said, since it's cold, I'll have the heat on with the fan on the third speed. Doing so, that needle will be just slightly past the second bar on the gauge. However, coming home during the middle of the day, the needle will rest at its usual position at just barely touching that thermo symbol. I know this is because I don't have the heat on to allow the engine bay heat to enter the cabin. So, seeing this, I've begin to wonder what would be a nice modification around the engine bay area to help remove the heat.

93 rx guy: I've actually thought about fender gills before, like the Z3. I completely forgot that the M3 had gills as well.

If anyone else has ideas, or what to do to the hood, lemme know. I might play around with PhotoShop to figure stuff out.

 

NO! they would not.

I have seen louvered hoods before. Does not look bad as long as there are not too many.

 

you can use any louver you want. its up to you. hood scoops and all.

you just have to cut out the sheetmetal and replace it with the louver.

theres no really factory car louvers. well accept on the glass

 

I saw once a drift fb with openings on the fender like the FD but more square... kinda following the body style. I liked them

 

You mean something like this? That actually looks pretty cool, I might go with that.

 

Do you guys realise how much ducting you would have to do for the fender vents to vent the engine bay? The fender vents are for brake cooling, not engine cooling.

If your cooling system is running hotter with the heater off, fix the cooling system, don't bandaid the problem.

Not trying to be a hard *** today, but a properly maintained cooling system, even a with modified NA engine, does not need extra venting. Is your belly pan in place?

 

I often drive in desert conditions with the outside temperature around 100 degrees, and there has never been a problem with water or oil temperature with either the s2 FMOC or s3 beehive set ups. The engine of a rotary sits low so the heated air easily flows out under the firewall. The only time you really need extra flow from a louvre is for a top mounted intercooler when its important to cool the very hot exhaust gases.

The classic cars of the 20s and 30s needed louvers as their engines sat high while the coolant was just water. If you like the old fashioned look, then fit louvres but it will make little difference to engine temperature, and may slow the car marginally down due to increased drag.

The heater really is an efficient second radiator. At times driving a V8 in similar 100+ conditions I have had to drive with the heater on and my head out of the window to stop the temperature going into the red. Its dreadful on dirt roads where rpm tends to be higher, and you need a face mask to breath!

 

Well, in my defense, I've figured that where the needle always rests is the normal operating temp. I don't know if it's 180 or 195, but it's never strayed past that "imaginary" mark on the guage. Even the 28 hour end of Spring drive (one-way) to and from Colorado, it never moved past. I do know that rotaries are known to run very hot (the FD's mostly with their overheating problem), however I know my engine bay is NOT overheating. I'm just looking to help keep it cooler.

Also, it's not uncommon for a lot of cars to not have a very hot engine bay when the heater is on full blast. A lot of guides suggest that if your engine is overheating (say the car has a stuck thermostat), it suggests to turn the heater on full blast to get rid of the heat as much as possible, a temporary solution to get to the nearest shop, of course. Having that blower motor on, on heat, removes most of that hot air from the bay.

And, belly pan? I've been under the car a few times but don't recall seeing a belly pan. I've seen the oil pan. Don't think I've seen a belly pan. Unless I overlooked it and it was bolted onto the chin as a scrape guard.

I just want to ensure my motor and the bay gets the best cooling available. I'm sure a louvered hood might do the trick, if I can figure a style out.

 

I recently saw a S2000 with fender vents. Thought it looked alright until I got closer and saw the quality of his work. The entire area around the vents was beatup like he made them with a pick ax then knocked the extra dents out. Maybe they worked like the dimples on a golfball and made his car faster?

Oh and Im in Austin where temps get well over 100 for 2/3 of the year. My SE stays right past the first mark on an all original cooling system...

-Erik

 

You posted this before I posted my reply. Thanks for the advice, the thought of the fact that a louvered hood could induce drag never occured to me. I guess I should just focus on a better cooling radiator (Rotary Performance says they have a 2-core and the original 13B's had 1-core).

 

If you want to let extra heat out for free and don't want to blast your heater, i know i'm going to get roasted for this, open your hood while you drive. It opens backwards anyways so the air will prevent it from flipping all the open but it will still baek the sael that the hood has with the body. I did this at a track day after my car reached 210 water temp, after i opened it it dropped to about 195.

P.S. over about 105 or so i think (my speedo goes to 85 only) the back side of the hood sort of floats about 6 inches above the body (which made for a good picture at that same track day).

 

85 FB

Summer time, I can actually see the heat rise from the vent in my hood.... You wanna try something like that?

Dan

 

yeah ive seen it in drifting videos "driftlanta"

he had his hood open. I guess it would help.

but I think hoodscoops look good anywase : )

and about drag. I dont think it will do much consider our lights are air brakes at night : P

 

You could put a TII scoop on your hood backwards, right over the engine. You could also bolt/weld/however sheets of aluminum on the underside, and just louver said sheets where it directs the air passing under your car up to your engine and out the scoop; also a great way to improve downforce and manage airflow under the car if need be. Better efficiency not only in cooling, but it aerodymanics.

 

Thats a good idea. And those pop up lights do actualy work as airbreaks. The drag coefficent with lights down is .3, and with the lights up its .34. Thats a big difference.

 

m3 fender vents are just what they are fender vents. they are not very functional. if you take off any vehicles fenders what do you see? just a metal wall, if there were actually tubes or pipes to connect the vents to the engine bay then at speed the effect will be: the fan will push the air to the back of the engine bay and the air outside moving around the car will create a vacuum thus evacuating the hot engine bay air. and the side effect for this is that the air blowing to the radiator is moving faster due to the vacuum from the vents. in effect increasing the efficiency of the cooling system... ok class thats all for today be sure to read the rotary rebuild book and view the video as we will rebuild an REW for your semester test and your grade will depend on how much horsepower and torque you make using an T66 ceramic turbo with the emphasis on torque being as close to horsepower as possible

 

at first i thought that you (nicholas p) were calling me "driftlanta," but then i did the dreaded search and found out that that is someones sn

 

Weedwacker - At 105, the hood floats. That's hilarious.

Lt. Dan - Yeah, I saw the design in the hood, looked wicked. Also, Kyle told me of his friend's side humps with vents and said the same thing: you could see the heat waves excrete from them. However, I think that would look odd on my hood.

rotaryfire - I see what you're saying, almost like cowl induction only the scoop is moved forward a bit. But, it would seem a bit out of place, to me anyways.

cptpain - That's exactly what I was thinking. Have some channels or sleeves or whatnot from the engine bay to the slots to allow air to move out. And, that explanation you gave I liked. Very detailed and I like how it also improves airflow cooling for the radiator. I just may go for that. Thanks!

 

Best way to vent your excess engine bay heat

 

THAT I actually like but not a fan of the carbon fiber. Well, I am, but not for my car. I prefer to keep it all white. They don't make fiberglass hoods for our series, do they?

 

 

I Seen Some Pic's Here In This Club Of A First Gen That Had The Piece Between The Front Headlights Vented For More Air Flow Into The Rad. It Looked Nice