Engine Temp. Experiment (heat extraction)

[Andrizzle]

Following the recent thread about cutting into your hood to allow heat to be extracted, I got curious and did some mocking up of adding vents into the Wiper Cowl.

The squares would lead directly underneath the strut bar and on both sides of the engine block. I also used this time to inspect how the water is handled off the cowl and off the wiper holes. The corners of the cowl lead off into little ducts that spit the water and debris to the ground. And the wiper holes lead down little spouts that pour directly into the engine bay. So that right there tells you that a little water coming in from that area into the back of the engine would not be a big deal (minimal water).

Also the vent design I had in mind would have a lip against the bottom side of the cowl where water pools up and runs either left or right that would prevent any water from just straight up draining into the engine bay.

The orange squares are roughly the straightest parts of the cowl surface.

So to see if the mod was even worth it, I wanted to see temperature comparisons from under the hood.
___________________________________________________________


*Each lap consists of roughly, .5 mile of Highway (75mph); 2 miles of city streets (35-45mph). With stoplight traffic identical to each other (I made sure of this to not skew readings). Air temperature outside: 79°F

**Transmitter was not moved in between laps.

***Also I want to add that, "Lap 2 Start" picture is taken when I had the hood open, however the reading displayed on the Temp. Station is taken with the hood down (there is a 60 second delay in between each reading). I forgot to snap a picture of the starting temp when I went back under the hood because I couldn't remember if I took a tool out of the engine or not (lol paranoid), so I took the photo real quick before the new temperature reading overwrote it.

****When it says 'operating temp.' that means I took the reading @ the exact time the car read the normal op. temp.

*****I did allow cool down in between laps, neither of them are from a cold start. Like mentioned, I let the car idle to normal temp. before starting each lap.

With Cowl:Average: 137.5°F
Without Cowl:Average 110.9°F


Comments: Obviously with the cowl is stock normal driving. But I want to mention that when I had the cowl off and was @ stoplights or sitting idle. I could physically see the heat waves rising up in front of the windshield. And when hovering your hand over the gap, there is some major heat being pulled through. I would say the difference is pretty extreme when looking @ compared idle temps; think of all the time you sit in traffic in the heat. Also it was only 80 degrees today. Think if this was on a day of 95+. That is alot of heat!

I am still not sure if I want to cut into my cowl or not, I will think about it some more.

Thanks for reading!

 

[lincoln_1999]

What a great experiment .

Have you tried taking the readings without the engine cover ???

Thanks for sharing .

 

[nearlyhalfamile]

Removing the engine cover should have no effect to the underhood temps.

I would like to see temp results from removing the weather stripping along the underside of the hood that seals with the cowl. This should have a similar effect to removing the cowl cover as you did.

 

[Missing Linc']

Boom! I knew this thing would benefit from some air being able to leave the engine bay. Good experiment man, helping me out a lot with this.

 

[Quik LS]

What I would think the right questions are:
- did the actual engine temp change?
- did the duty cycle of the fan change?

certainly if you allow air to flow more over your gauge it's gonna read lower - did it actually do anything for the engine?

good experiment - do you have an SCT or other ODBII logging?

I have four points where I monitor temps
- the outside temp sensor just behind the grill
- the temp probe in the output of the supercharger
- the IAT - which is post intercooler
- the actual CHT - engine temp

 

[Andrizzle]

Removing the engine cover should have no effect to the underhood temps.

I would like to see temp results from removing the weather stripping along the underside of the hood that seals with the cowl. This should have a similar effect to removing the cowl cover as you did.

Actually the rubber seal under the hood makes a seal against where the wiper cowl meets the strut bar. So it goes, from bottom up, strut bar, cowl, hood seal. The wiper cowl is the actual bridge from between this strut bar and the windshield bottom. Removing the stripping would only allow about a quarter to a half inch gap between where your hood actually comes water tight against the top of the cowl. I'm sure it would help remove some, but this theory involves large cut outs in the cowl.


Yea QuickLS those are definitely questions that this experiment would not be able to answer (by me anyways). However, I think when looking @ a daily driver standpoint of how much heat is held inside the engine bay with no ventilation it is fair to say less stagnant hot air is better, correct? I am sure the heat under the hood has an exothermic effect on the actual engine parts. To what effect, not sure.

I think it really comes into perspective about how much heat is really bottling up in there when the person in front of you's license plate is distorted due to the heat waves.

 

[exceptionaLS]

Thanks for doing the experiment. I had overheat issues and sold my LS, I think that doing this would be benificial to lower operating temps. Maybe there's a way to fab a fan somewhere in the back of the engine bay to keep continous air flow... just my 2 cents. On another note, I bought a chevy impala after selling the ls, and the intake is directly behind the drivers headlight, it doesnt even have a fender well or anything for air intake, im assuming the airflow is very restriced. I was considering putting a scoop in the hood for ventilation purposes as I am in New York city alot and it's gotta be tourturous with all the heat.... good luck man, I think it's a good idea. Just see I you can somehow fabricate a piece for the cowl that has an angle where water won't be dripping in.

 

[LS4me]

On another note, I bought a chevy impala after selling the ls

That has to be a let down!

 

[exceptionaLS]

That has to be a let down!

only in handling and style...i had the v6 ls, the impala is 3.8 .... plus i know its cheaper and easier to maintain

 

[NYC LS8]

I monitored the intake air temperature with my ScanGaugeII and have seen temps at or near 180 degrees while sitting in stop and go traffic. Once you start moving, it comes down rather quickly.

Good idea with the cowl, but I'd be hesitant to do that seeing as how I just had to replace a coil today due to water getting into the #4 cylinder (for some time apparently, since the spring inside the coil boot was rusted). If you were to do it, I'd RTV the coil covers to prevent water giving you problems in the future.

 

[386Motoring]

I monitored the intake air temperature with my ScanGaugeII and have seen temps at or near 180 degrees while sitting in stop and go traffic. Once you start moving, it comes down rather quickly.

Good idea with the cowl, but I'd be hesitant to do that seeing as how I just had to replace a coil today due to water getting into the #4 cylinder (for some time apparently, since the spring inside the coil boot was rusted). If you were to do it, I'd RTV the coil covers to prevent water giving you problems in the future.

x2

I may be wrong, but i thought motors had to maintain a certain temperature. I can understand where running cooler would help, but if the motor is 180 degrees then i'm sure there is a downside to it

 

[Andrizzle]

The center Wiper hole drains more than half the water off the middle of the windshield and it spits it right into the center-back of the engine bay. It looks like this water could hit the coil cover on the drivers side.

So if you are already getting water in your coils, which ones in particular are being effected? It seems like the driver side coils closest to the back of the engine would be the most susceptible.

 

[Fla02LS]

I have been "pro" venting of the engine bay, but i think there is a fine line here with your experiment as quik touched on. There is a difference between removing some underhood heat and actually cooling the engine. Your experiment may well have helped remove some excess heat but that doesnt exactly mean there is any actual peformance benefit. I think your engine is going to run at the same temp no matter what you do with venting. Operating temp is operating temp. I see the benefit from removing "excess" heat to help with the wear of various underhood components- hoses, coils, etc.

 

[Former Member]

EDIT: ^^^^how do you have a triple black LS? they didnt come in convertables

some engines are designed to run hot.

The Lt1 engine is a perfect example. its most effiecent when its running at factory temps. Also they have dyno proven results that they are unaffected by heat. thats another thing to consider with this. they did dyno runs on a lt1 from mildly cold to as hot as it will get. zero power change. however people who put in cooler t-stats actually showed power loss since the engine isnt at the most efficent operating temp.

If our engines have any type of cooling systems like a lt1 (coolant doesnt flow through the intake manifold) then it would most likly be unaffected by a change in engine temperature when it comes to performance. there might be a benifit of getting that hot air out of the engine bay to ease the strain on the failure prone hydraulic fan though, and maybe even the coils. but replacing hot air with water wouldnt be good if it leaks lol.

 

[Missing Linc']

I still have no idea why people stick to dyno numbers when trying to prove things. Ever wonder why your E/T's drop if you hot lap the sh!t out of your car? Exactly, the engine/engine bay is getting heat soaked and causing it to perform lousy. Thats why everyone whos smart lets their motor cool down some before running it again, popping the hood, keeping the fans running, sh!t like that..

 

[NYC LS8]

So if you are already getting water in your coils, which ones in particular are being effected? It seems like the driver side coils closest to the back of the engine would be the most susceptible.

The one I changed yesterday was the number 4 cylinder - rear passenger side. I have another one that's on the way out since it's still sputtering, so maybe the rear driver's side needs to be replaced too.

 

[Quik LS]

I still have no idea why people stick to dyno numbers when trying to prove things. Ever wonder why your E/T's drop if you hot lap the sh!t out of your car? Exactly, the engine/engine bay is getting heat soaked and causing it to perform lousy. Thats why everyone whos smart lets their motor cool down some before running it again, popping the hood, keeping the fans running, sh!t like that..

I think that is a little over-simpified. Most of the time 'heat soak' is referring to heat exchangers becoming hot themselves, and therefore not able to transfer heat away from the fluid/air needing cooling - for example - intercoolers.

while true that the engine is generating heat, and the car is getting hotter, your temperature gauge is the proof that the engine is not getting gaining heat. metal objects - (intake tubing, ...etc) warm up but are quickly cooled once the car moves - and the intake temp quickly match the outside temp.

I own two cars that use heat exchangers - and both need to be moving to keep the air-to-air or liquid-to-air intercoolers operating at peak cooling.

 

[rainjacks]

Good experiment. It helped the community gain additional information. And like all good experiments it generated more questions than answers. I am happy that we have another person willing to actually do some work and gather information instead of just putting out opinions. Which is to be fair is almost all I do.

 

[Lincoln Jealous]

i just want to say, that if the engine bay temp dropped, that means the for the people with cai that sucks air from the engine bay-even with the heat shield, it would benefit them, if the air into the engine is cooler, it should have some performance gain,??

 

[Lincoln Jealous]

I still have no idea why people stick to dyno numbers when trying to prove things. Ever wonder why your E/T's drop if you hot lap the sh!t out of your car? Exactly, the engine/engine bay is getting heat soaked and causing it to perform lousy. Thats why everyone whos smart lets their motor cool down some before running it again, popping the hood, keeping the fans running, sh!t like that..

dont forget the bags of ice!

 

[Quik LS]

i just want to say, that if the engine bay temp dropped, that means the for the people with cai that sucks air from the engine bay-even with the heat shield, it would benefit them, if the air into the engine is cooler, it should have some performance gain,??

not as much as you would think.
a couple of years ago I datalogged 3 senarios:
- cone filter in the engine bay
- cone filter in a sealed box with a tube feeding it from the lower grill
- cone filter in a sealed box feed through a hole in my hood

True - the IAT did rise while sitting - engine on. but once the car started moving it dropped quickly.

the 'ram' air from the lower grill was a little better - but once again, sitting - engine on - it would heat up a bit (not as much as only engine bay)

So the launch may be affected by the initial warn air - but once moving - it seems to be the same as outside temps quickly.

 

[Missing Linc']

Well I dont know about most of you guys but my car SUCKS at coming out of the hole, I get nothing till 3K+ so maybe some cooler air while sitting still might help, next time I hit the track Ill do this same senario and remove my cowl to see if it benefits.

 

[Andrizzle]

I think removing the cowl and sitting in traffic really puts it into perspective. I am not exaggerating when I say the heat waves just pour out.

Also thanks guys for the comments, I like to do these kind of things to give other people and myself actual photos and numbers to learn more information about the LS. I did something similar when I installed all new interior LEDs; giving before and after photos. It is simple things like this that we can use to our knowledge and bettering of our cars!

Also I want to add, removing the wipers makes the front look reallll cleannnnn. lols. I haven't put mine back on yet cuz I am lazy.

 

[Missing Linc']

Oh! Oh! Do the JDM single wiper swap pleeeeeaseee!! LMFAO

 

[Lincoln Jealous]

Well I dont know about most of you guys but my car SUCKS at coming out of the hole, I get nothing till 3K+ so maybe some cooler air while sitting still might help, next time I hit the track Ill do this same senario and remove my cowl to see if it benefits.

have you changed your fuel filter recently? i had this problem and it seems to have improved after replacing the fuel filter