Engine bay heat management

[Erik W. Treves]

With my turbos in the car and the how well the coupe is sealed as far as the engine... I noticed the other day that actual frame bars in the foot well were HOT...the carpet was't as bad obviously but the heat from the frame was pretty good... grant you this was after 1 hour driving on the highway as well... I have notice it during short drives as well but figured it was about like the roaster so I dismissed it...

The big difference I think is the way the radiator shroud doesn't allow the air to flow "through" the car - rather it is ejected in front of the engine bay.... I remember seeing Peter Brock's personal car LS7 powered, had hood vents in it - so even the master was evacuating air out of the hood.

I really wish I had put hood vents in my car... I know that after driving there is a tone of heat pouring out around the car... and not even spirited driving either... the engine bay is that sealed up ...

Anyway - I had a long conversation with Jim at factory five since he taken the coupe to the wind tunnel. We discussed the side screens and the fact that they do work - but there is high pressure air that gets stuck at the top of the engine... matches what I was seeing... to add to this my air intakes to the turbos are in the wheel well right by the upper and lower control arms (really the only place they can go) - they never really see "fresh" air...

So after a couple weeks of thinking about it... and looking at where all the dirt is hitting in the wheel wells... I decided to again modify my completed car...lol... and cut into the paint job...

Basically the way this seems to work is the high pressure right below the nose gets push through the tucked away naca duct and forces fresh air right at the air filter area - but inside the inner edge of the wheel and past the primary debris path of the tire. The high pressure then escapes out the back of the wheel well through a screen and then exits either out the bottom of the car or out the side screen.... I mounted a leaf blower out in front of the car - and sure enough the tags on the turbo blankets were "flapping" indicating we had flow where once there wasn't.

I did the mod in two stages - first stage was just the naca ducts... this was to see if the intake temps were effected... sure enough - yes - while under boost, before the temps seems to come down very slowly after a blast... now they come back down much much faster... so with that I cut the rear vent - while on tried it for a bit < 1 hour ... initial feedback seems that the temps on the foot box are indeed less!

anyway - those are the details... I have one more screen I might put in - but I need some miles in this configuration to see the changes...

https://thefactoryfiveforum.com/attachment.php?attachmentid=132532&d=1595854271

https://thefactoryfiveforum.com/attachment.php?attachmentid=132530&d=1595854247

https://thefactoryfiveforum.com/attachment.php?attachmentid=132531&d=1595854259

[Straversi]

Love the wind tunnel/leaf blower idea. Very creative.
-Steve

[edwardb]

Interesting stuff. Thanks for posting. Will be watching for some follow-up. I haven't noticed that too much on mine yet. But with only about 700 miles, still kind of getting used to it. But going to check a little closer.

[Gbeck]

This is very timely for me as I'll soon be mounting the body on my Gen 2 coupe for final fitment. I plan to add vents about 24" forward of the base of the windshield to get some of the heat out from under the hood. But I hadn't given much thought to air flow into the area under the hood.
BTW, I remember a post from some years ago where the OP observed air flowing into the side vents.

[GoDadGo]

What A Great, Functional & Super Cool Idea!

.Making it look good too is truly the icing on the cake.

[Erik W. Treves]

I can't really comment for which way the wind goes through the side vents - my only reference is what I got from wind tunnel testing from FFR... I will note that my vents seem to be "pushed in" at times...

Paul - in short duration exposure ( not total distance) I don't experience anything out of the ordinary - It was most obvious on the 95* degree day driving on the highway for over an hour (over 115 miles ) ... also at autox.... if you are just doing normal driving I wouldn't expect it would be too bad.. about like the roaster I guess...

I will also point out that my turbos are a little closer to the footbox that NA headers - but not much and the turbo and pipes are wrapped.

but I will say that I went over to Logan's house this weekend to see his progress on his R... and even after about 15 minutes sitting there, we walked out to my car the heat was still pouring out of the wheel wells.. he even noted it ...

It's not a HUGE problem - but since I use my car quite a bit - cleaning up these little things is where I am while I am bored sitting in my garage :)

I am over 5000 miles now - and 2 sets of tires :)

[Erik W. Treves]

What A Great, Functional & Super Cool Idea!

.Making it look good too is truly the icing on the cake.

thanks!

[NiceGuyEddie]

Erik:

I've been watching your stuff since FFR1879 and you never cease to amaze me. I can't believe nobody thought of this trick before. Seems so obvious now!

You need a YouTube channel, even if it's just camera phone stuff.

[Erik W. Treves]

always tweaking the design :)

[GoDadGo]

Erik,

What if the aluminum panel behind the radiator was louvered?
It would likely extract air from engine compartment air in addition to the air passing through the radiator.
Dimple dye holes might work too; however, upward-facing louvers would better extract air since that entire area is a low-pressure spot.
What-Cha-Think?

Steve

[Erik W. Treves]

I had thought about this a little - that would work i suppose, but would defeat the primary design around the way it is now (in my opinion) - it also would be heated air... but there would be flow so that is a plus... I was thinking of putting vents in that area as well ... but on a completed car - and some discussion with FFR - this is where I landed...

[Bob Brandle]

If one were to "delete" the fog lamps in the nose, then those two ready made scoops could have their rear panels removed, an air hose connected to each and then routed rearward to wherever the cool air is needed in the engine compartment.
Of course most of us wouldn't want to have the fog lamps deleted, but if the lamps weren't too large and there was a sufficient gap around the lamps, the rear of the scoop could still be removed, ducting connected and routed. Less airflow with this second design, but maybe still effective enough. It would be a very stealth design too.
The double vents on top of the hood on either side of the engine is a good idea and would work in tandem with any added front scoop(s) design.

I'll be trying both of these ideas on my Gen 3 Coupe, fog lamp ducts and top of hood vents.

Bob

[Erik W. Treves]

The problem with the fog light delete is that is where the hood hinge is attached to... I would have done that in a second and run fog lights in the rad opening... I like that look for sure... the vents on top of the hood would be my first choice... Herny's coupe is that way ... plus it looks really nice. Not saying the fog light area won't work.. but you would need to redesign the hood hinge... my opinion anyway... post up whatever you do please...

[Jim1855]

Eric,

You're fighting a battle that most will not experience. The turbos are not easy on under hood temps.

The Superformance Coupes have hood vents. I would think that these would help you as well. Then if you could pull cold air into the engine compartment it should drop under hood temps.

With my previous roadsters I could lift the back of the hood on the locks. This would open up about 3/8" gap across the back of the hood. It really helped in slow traffic. You could watch the heat waves at traffic lights.

Jim

[Erik W. Treves]

Yep agree with all that.. if I was super brave I would cut into the top the hood and put some vents in there as well

[John Dol]

Yep agree with all that.. if I was super brave I would cut into the top the hood and put some vents in there as well

After all you’ve done so far I don’t think cutting a couple of holes in the hood would be out of the question.

132575

John

[Logan]

Erik, thanks for stopping by over the weekend! Good to get another pair of eyes validating my progress. I’m planning to add some rolled beads to the upper coolant tube this week.

On the heat topic, I agree I’d be somewhat apprehensive to cut huge holes in the top of a painted hood, but it is probably the best (most efficient) option to evacuate heat which naturally wants to rise anyway. Painters tape on the hood, lots of careful measuring and cutting, and the vents will cover the cut edges of the openings. I know you could make them look perfect!

I also like the work you’re doing before committing to cutting the hood (if you decide to). The NACA ducts in the nose sending fresh air past the inside of the wheels, through the new opening in the back of the wheel wells, over the turbos, then out the sides of the hood seem to be making a nice improvement. Airflow, even if it is hot air, is better than no flow at all. A GoPro camera and some light yarn could be a good test for flow dynamics.

Heat transfer comes in three forms: conduction (direct contact), convection (through air), and radiation (electromagnetic waves, such as a turbo or header that is glowing red for example). Since your turbos and headers are wrapped, that’s helping with thermal radiation. Adding more incoming airflow will help with convection, lowering the overall air temp under the hood. Conduction shouldn’t be much of a problem, unless the header or turbo was touching the frame somewhere, which it likely can’t be or you’d have other problems with noise and vibration. I’m eager to learn more on solving this one!