A discussion on mitigating engine bay heat

[Maisonvi]

So obviously a running engine will get hot, and that is exacerbated at places like the track. Ive had issues where my engine bay in august is just crazy hot at the track. (like hose melting hot) I have seen high coolant temps, but that’s not completely due to high engine bay temperatures, but those hot things like manifolds and a turbo being pushed hard isn’t helping anything.

So I figured I would start up a conversation on what people are doing to keep your engine bay cool. I have tossed around the idea of wrapping my CPE manifold, but I see no good way to do that. A turbo blanket might be on my list as well as a possibility. Anyone else have suggestions or things they have done to help keep things cooler? Im wondering about ducting, wraps, coatings, vents, anything you have thought about. Really I just want to keep things cooler.

 

[punkk77]

Are you trying to keep specific components cool? I can only really offer advice on coolant hoses.

Most reinforced epdm rubber hoses are good for about 135C peak driving temps. At 150C, they will degrade exponentially faster. Depending on what youve added or moved, you could look into heat shields for certain hoses. A hose that requires a Clevaflex heat shield could be 3 inches from one that doesnt.

Ive got some shielding if you find anything you want to wrap. As far as anything really worthwhile for engine bay heat, ive got nothing.

sent from the Tardis

 

[Maisonvi]

Are you trying to keep specific components cool? I can only really offer advice on coolant hoses.

Most reinforced epdm rubber hoses are good for about 135C peak driving temps. At 150C, they will degrade exponentially faster. Depending on what youve added or moved, you could look into heat shields for certain hoses. A hose that requires a Clevaflex heat shield could be 3 inches from one that doesnt.

Ive got some shielding if you find anything you want to wrap. As far as anything really worthwhile for engine bay heat, ive got nothing.

sent from the Tardis

Yeah Im looking more for ducting and just general under hood heat dissipation. The manifold radiates a lot of heat I would perfer went out the exhuast or at least away from where I take in air for the motor.

The shielding on hoses might be a good idea still though. Im thinking of moving my EWG hoses to SS lines to help protect them.

 

[Raider]

I know some have used gold foil to wrap. I have seen old school guys use Jett Hott on exhaust manifolds and other exhaust parts, which drops temps.

 

[Maisonvi]

I know some have used gold foil to wrap. I have seen old school guys use Jett Hott on exhaust manifolds and other exhaust parts, which drops temps.

Ive seen the coating Relentless offers for manifolds. Im curious if that would help.

Also another thing I thought of with your reference to gold foil wrap, Ive seen people put reflective foil on the underside of their hoods, not sure how much that would really do though.

 

[VTMongoose]

Have you tried removing any of the undertray/fender liners...etc...to see if that makes a difference?

 

[Maisonvi]

Have you tried removing any of the undertray/fender liners...etc...to see if that makes a difference?

I do have the under tray gone, and the weather strip between the hood and the cowel removed. I made my own air damn as well, but its not installed, need to get that back in. I figure the more I can do the better. Really I should try and collect some data on what Ive done to see what makes a difference.

 

[Redline]

Yeah Im looking more for ducting and just general under hood heat dissipation. The manifold radiates a lot of heat I would perfer went out the exhuast or at least away from where I take in air for the motor.

The shielding on hoses might be a good idea still though. Im thinking of moving my EWG hoses to SS lines to help protect them.

Have you tried removing any of the undertray/fender liners...etc...to see if that makes a difference?

Seems like these wouldn't be a good idea, particularly for high-speed driving conditions. Channeling air into the engine bay would increase drag, decrease downforce, and could even potentially generate front-end lift, which could be very dangerous at high speeds. I've heard that removing that rear gasket by the wipers can help evacuate heat, like was mentioned; I've never seen quantified data on it, though.

The approach EVOs have used (from the factory) is that cut-out/screen right over the EM/turbo to help evacuate heat. I don't think they have extra air channeled into the underhood area besides what's aimed toward the radiator/IC. Maybe we need to look at cutting out a section of hood toward the back, right over our EM/turbos? EVO engineers seem to think that it helps.

 

[Maisonvi]

Seems like these wouldn't be a good idea, particularly for high-speed driving conditions. Channeling air into the engine bay would increase drag, decrease downforce, and could even potentially generate front-end lift, which could be very dangerous at high speeds. I've heard that removing that rear gasket by the wipers can help evacuate heat, like was mentioned; I've never seen quantified data on it, though.

The approach EVOs have used (from the factory) is that cut-out/screen right over the EM/turbo to help evacuate heat. I don't think they have extra air channeled into the underhood area besides what's aimed toward the radiator/IC. Maybe we need to look at cutting out a section of hood toward the back, right over our EM/turbos? EVO engineers seem to think that it helps.

Yeah, Ive never really seen anyone cut anything out of the hood for heat, but I have to imagine a vent above the EM would help a ton. Am I ready to go that far? Dont know yet.

Really its hard to gather proper data with so many varying conditions day to day.

 

[Redline]

Yeah, Ive never really seen anyone cut anything out of the hood for heat, but I have to imagine a vent above the EM would help a ton. Am I ready to go that far? Dont know yet.

Really its hard to gather proper data with so many varying conditions day to day.

Indeed. It would be a no-going-back mod for sure, LOL. Then again--and maybe some of the engineering-degreed folks in here can speak to this--the hole would be right near the transition from the hood to the windshield. The change of airflow direction right there seems like it may create a low pressure zone and effectively pull air out from underneath the hood rather than let it just emanate out. This could be all the better, extracting even more heat. The design on the EVO hood incorporates planes/angles/venturi to help, probably due to their vents' location near the front of the hood.

If it were me and I had my heart set on it, I may ask a body shop how they'd go about doing so. I'd want to source some good screen to put over the hole, and maybe run a gasket ring around the cut hood itself to make it look better.

 

[Maisonvi]

Indeed. It would be a no-going-back mod for sure, LOL. Then again--and maybe some of the engineering-degreed folks in here can speak to this--the hole would be right near the transition from the hood to the windshield. The change of airflow direction right there seems like it may create a low pressure zone and effectively pull air out from underneath the hood rather than let it just emanate out. This could be all the better, extracting even more heat. The design on the EVO hood incorporates planes/angles/venturi to help, probably due to their vents' location near the front of the hood.

If it were me and I had my heart set on it, I may ask a body shop how they'd go about doing so. I'd want to source some good screen to put over the hole, and maybe run a gasket ring around the cut hood itself to make it look better.

As an engineer, its hard to say what would happen. Really I would love to test air velocities at points to see what is going on in and over the hood, but I dont see this as an easy thing to measure. Idealy airflow in the engine bay would be directed down under the car I would think, so then something like a hood scoop would work/help.

I think to start a turbo blanket is the easy thing to do. The thought of pulling the CPE to have it coated makes me shutter, but reading shows some impressive results.

I was just curious to get peoples thoughts and see if anyone has tried anything interesting and what the results were.

 

[Redline]

As an engineer, its hard to say what would happen. Really I would love to test air velocities at points to see what is going on in and over the hood, but I dont see this as an easy thing to measure. Idealy airflow in the engine bay would be directed down under the car I would think, so then something like a hood scoop would work/help.

I think to start a turbo blanket is the easy thing to do. The thought of pulling the CPE to have it coated makes me shutter, but reading shows some impressive results.

I was just curious to get peoples thoughts and see if anyone has tried anything interesting and what the results were.

Maybe start with the turbo blanket and remove the back-of-engine-bay gasket? You have a Won, right? Do you have a similar gasket that seals back there like us Pu's do? Sounds like removing the CP-e is a nightmare. Coatings are always best applied before first install, LOL

 

[Maisonvi]

Maybe start with the turbo blanket and remove the back-of-engine-bay gasket? You have a Won, right? Do you have a similar gasket that seals back there like us Pu's do? Sounds like removing the CP-e is a nightmare. Coatings are always best applied before first install, LOL

Yeah Gen 1. And I completly regret not sending my CPE out for coating first. I thought about it, just didnt do it.

 

[Easter Bunny]

The base of the windshield has a higher pressure than the engine bay when the car is moving. The rear weatherstrip should only be removed on drag cars where you sit in the staging lane.

You should put the understray back on.

Turbo blanket, coating on the manifold and some heat shields around the turbo will help too.

Pretty sure you are fmic in which case you should make sure that any radiator shrouding that was removed for the installation of the piping is modified so that in can be replaced.

The idea being that the stock configuration is pretty well designed and the removal of a bunch of small parts from the stock setup can add up to a big difference in temps.

 

[Redline]

The base of the windshield has a higher pressure than the engine bay when the car is moving. The rear weatherstrip should only be removed on drag cars where you sit in the staging lane.

You should put the understray back on.

Turbo blanket, coating on the manifold and some heat shields around the turbo will help too.

Pretty sure you are fmic in which case you should make sure that any radiator shrouding that was removed for the installation of the piping is modified so that in can be replaced.

The idea being that the stock configuration is pretty well designed and the removal of a bunch of small parts from the stock setup can add up to a big difference in temps.

Thanks for weighing in. Technically the high pressure zone would be about a foot behind the vent, placing it at the very base of the windshield, right? So couldn't there be scavenging going over the vent itself, thus pulling hot air out?

 

[Maisonvi]

The base of the windshield has a higher pressure than the engine bay when the car is moving. The rear weatherstrip should only be removed on drag cars where you sit in the staging lane.

You should put the understray back on.

Turbo blanket, coating on the manifold and some heat shields around the turbo will help too.

Pretty sure you are fmic in which case you should make sure that any radiator shrouding that was removed for the installation of the piping is modified so that in can be replaced.

The idea being that the stock configuration is pretty well designed and the removal of a bunch of small parts from the stock setup can add up to a big difference in temps.

Thanks for the post. Do you know if there has been much testing on different configurations. Or have a recommend for a testing method? trying to lay out a plan of testing this summer.

Yeah the strip behind the hood came out not on purpose but because the holes have ripped and it no longer stayed in place. The under tray isnt going back on because I work on the car too often and god I hate dropping tools on it not to mention it was in rough shape But maybe the idea of making my own under tray that is easier to remove should be up on my list. I would be very curious to see the results of with and without one, so maybe some testing is in order.

Ive kept as much radiator ducting as possible, and really plan to add more where possible just to keep coolant temps down. That along with an aux fan controller.

This is where I was at with things, I assume mazda knew what they were doing and it flows well under hood, but Ive also made more than a few changes so I dont know how much of that still hold true.

 

[Easter Bunny]

how do you use the car typically? if your concern about heat is primarily while you are moving, the fan wont actually help, you don't actually need a fan on a moving car.

ncvspec81 or whatever the fuck his name is, i think is the one that did a bunch of testing with pressures

i would be interested to see what happened to your temps by simply replacing the undertray and cowl gasket. you have the parts already so it would only cost you time to experiment.

the pu tray isnt that bad other than the plastic push clips, if i needed it off more often i would probably put a stud/bolt and nut through the mounting hole and use one of those nuts with nylon in the middle to secure it.

[doublepost=1462465588][/doublepost]

Thanks for weighing in. Technically the high pressure zone would be about a foot behind the vent, placing it at the very base of the windshield, right? So couldn't there be scavenging going over the vent itself, thus pulling hot air out?

thats tough to say without analyzing the under and over pressures while the car is moving, though you could always place a scoop facing to the rear, the profile of the scoop above the hood would create a low pressure area for sure, you would just need to make sure that it is far enough in front of the high pressure cowl area.

 

[Maisonvi]

how do you use the car typically? if your concern about heat is primarily while you are moving, the fan wont actually help, you don't actually need a fan on a moving car.

ncvspec81 or whatever the fuck his name is, i think is the one that did a bunch of testing with pressures

i would be interested to see what happened to your temps by simply replacing the undertray and cowl gasket. you have the parts already so it would only cost you time to experiment.

the pu tray isnt that bad other than the plastic push clips, if i needed it off more often i would probably put a stud/bolt and nut through the mounting hole and use one of those nuts with nylon in the middle to secure it.

[doublepost=1462465588][/doublepost]

thats tough to say without analyzing the under and over pressures while the car is moving, though you could always place a scoop facing to the rear, the profile of the scoop above the hood would create a low pressure area for sure, you would just need to make sure that it is far enough in front of the high pressure cowl area.

Well its 2 fold for me. The fan controller is for when Im sitting in traffic and I see the coolant temps climb. The air flow would be for the track days when I see temps there climb because of load.

I think Im pretty much slated myself to do some testing on this over the summer here. Im curious now about the benifits and draw backs of certain things. I need to find a good way to measure air speed, and possibly a longer thermocouple as I dont think the one I have will reach from in the car to the engine bay.

 

[Redline]

Well its 2 fold for me. The fan controller is for when Im sitting in traffic and I see the coolant temps climb. The air flow would be for the track days when I see temps there climb because of load.

I think Im pretty much slated myself to do some testing on this over the summer here. Im curious now about the benifits and draw backs of certain things. I need to find a good way to measure air speed, and possibly a longer thermocouple as I dont think the one I have will reach from in the car to the engine bay.

Not sure if you've done it yet, but have you considered adding an aftermarket oil cooler? That, a bigger radiator, the aux fan controller, making sure necessary ducting is in place for the radiator, a turbo blanket, and high performance thermal coatings would really help. Then, you can step it up a notch and cut a hole in the hood because racecar and uniqueness!

 

[Easter Bunny]

What weight oil are you running? Heavier oil will run cooler. Though you have to be careful to use a weight appropriate for the typical use so you probably cant go heavier than 50 or 60