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Hood louvers - sanity check

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
As the temps start to creep up here in the PacNW, I'm realizing the need to vent my engine bay is going to be real in about a month. Rather than wait, then panic, I'm going to do the work now. I figure i'll also get my aerocatch hood latches installed, too. What I'm seeing now is actually fine and dandy, but I don't think it stays that way when it's 20F hotter...

Current setup:

Ebay Scirocco radiator
Custom Radiator frame from our good friend, EHMotorsports
high-flow puller fan
Autozone Hayes pusher fan (couldn't fit two 12" pullers on the back of the rad)
Running 100% water w/ a bottle of water wetter for the summer
180F thermostat
custom exhaust manifold shield w/ gold heat tape on the inside (other Evan special)
underhood completely insulated w/ heat sheilding


So here are the assumptions I'm making:

1. Hood louvers - If just cut a hole and drop a grate into it, I'm going to increase the positive pressure under the hood, slowing the flow of air through the radiator and actually increasing. So louvers are a must

2. Doubtful I'm going to find baffles, so I need to place the louvers forward enough to catch the heat coming into and off the top of the manifold cover, but not so far back that rain can get into my valve cover and ruin my day.

Are my assumptions correct, here? Placement is really my biggest question.

Thanks in advance for the advice (whomever offers it). Recommendations for louvers are appreciated. I've got a FLIR camera and I'll track my results for the community.
 

tektic

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Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
100% water does not provide lubrication for the water pump and causes excessive rust throughout. What's wrong with coolant?

180 is not the temp the computer sees as operating temp. Under certain conditions you will be in the wrong cell of some temp based maps.

You can block off all the other flow so as to create a low pressure zone in front of the rad. That will significantly help the cooling effect of the air while moving. That should be designed in to the way the louvers are positioned.
 

slugsgomoo

Well-known member
Joined
Oct 16, 2003
Messages
3,776
Location
Tacoma, WA
have you done ducting for the radiator to ensure air isn't able to bypass it?

My experience with the 180* thermostat in a fairly stock setup is that due to when the factory fan switch turns on the ECU reads considerably hotter by the time the fans kick in (if you're sitting ~205* on and 190* off). I've considered moving my fan switch up to the top of the radiator on the "hot side" versus near the outlet due to having it kick the fans on earlier that way.

I think my issue right now is ducting to the radiator and manifold/o2 shields at this point. Also, have you considered getting a turbine blanket? I know with the FP manifold on a friend's car, with the manifold blanket you could touch it bare handed with the car at temp. Reducing manifold/turbine/o2 temps like that will go a long way.
 

marvinmadman

Well-known member
Joined
Nov 10, 2003
Messages
2,355
Location
Lafayette, Louisiana
I too will be visiting with some hood vent ideas in the near future. It's been 87° already down here.
 

turbohf

Well-known member
Joined
Nov 18, 2011
Messages
540
Location
Lake Stevens, WA
i want some holes in my hood also. my car seems ok at anything below 80* ambient temp now. and it doesnt have AC, so really i probably wont be putting many miles on it when its hot out.

i was thinking of something like this:
carbon_fiber_hood_89_93_mitsubishi_galant_invader3.jpg

99-03-Mitsubishi-Galant-Monster-Hood-102140-4.jpeg


either a CF hood or i cut a vent in. but that one looks too far back, dont want rain pissing onto my valvecover or turbo manifold.


Quote:
100% water does not provide lubrication for the water pump and causes excessive rust throughout. What's wrong with coolant?



water conducts heat better than a 50/50 coolant mix.
 

tektic

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Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
Quoting turbohf:

water conducts heat better than a 50/50 coolant mix.



Imho not worth it.
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
Gah, my bad!

190F thermostat

I'm running water w/ water wetter, not just water. Water wetter has all of the additives, but without the ethylene glycol, so it should be a-ok.

Can you expand on the "block off other flow" comment? Do you mean block off other air passages around the radiator to effectively force air coming in through the front to push through the radiator?

Quoting tektic:
100% water does not provide lubrication for the water pump and causes excessive rust throughout. What's wrong with coolant?

180 is not the temp the computer sees as operating temp. Under certain conditions you will be in the wrong cell of some temp based maps.

You can block off all the other flow so as to create a low pressure zone in front of the rad. That will significantly help the cooling effect of the air while moving. That should be designed in to the way the louvers are positioned.

 

turbohf

Well-known member
Joined
Nov 18, 2011
Messages
540
Location
Lake Stevens, WA
you want to make sure that no air can escape around the radiator, 100% needs to flow into the core. put in some plastic/sheet metal diverters, camper/door foam tape, whatever you can find... i still need to do this also. keep forgetting.
 

EfiniX

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Joined
Oct 18, 2012
Messages
647
Location
portland, or
At speed.
 

tektic

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Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
What he said. No leaks. Force all the air through the rad.

Another thing that will help reduce temperature would be a nice size air oil cooler.
 

EfiniX

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Joined
Oct 18, 2012
Messages
647
Location
portland, or
Oil cooler went in a few months ago. Definitely worth it.
 

Olson

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Joined
Oct 7, 2006
Messages
1,237
Location
Moreno Valley CA
Quoting turbohf:
you want to make sure that no air can escape around the radiator, 100% needs to flow into the core. put in some plastic/sheet metal diverters, camper/door foam tape, whatever you can find... i still need to do this also. keep forgetting.



Ducting end of story
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
Quoting tektic:
Are you driving closer to the sun than everyone else?



Lol. I'm just reflecting on what 100+ temps led to last year. Dropping in a 180 thermostat and a bunch of wetter helped, but ultimately, I found myself driving very cautiously on very hot days. And that was all before I replaced the heat shielding on the underside of the hood with insulated shielding.

I'll create some barriers and force more air into the radiator. Ultimately, if I can spare myself the trouble of vents, I will. This is more of an exploratory question. If I get to that point, how should I approach solving the problem.

In fact, back to that: anyone have an opinion on where louvers should go and recommendations for type/brand?
 

Olson

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Joined
Oct 7, 2006
Messages
1,237
Location
Moreno Valley CA
click


All depends on where you want to draw heat from and how crazy you want to get
 

tyeler18

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Joined
Jul 16, 2012
Messages
130
Location
Casa Grande, AZ
I live in the middle of the desert in AZ so I feel I have a fair understanding to the situation seeing as how I daily my galant in 120F as well as track it. I can tell you the fans are key. I have full working AC and it was 105F out today and I happily boosted along and sat in stop and go traffic at 185F with the AC full blast. I'm running a 1g mishimoto X line (3 core) which helps tremendously, a 180F t-stat, and I'm using a stock galant pusher fan and a stock 1g puller. It's a very tight fit and required a bit of clearancing, but the engine without AC on will hit 204-205 and drop back to 190F as soon as the fans kick on. If I have the AC on full (green light), fans on high speed all the time I can idle for hours on the t-stat. The fans are what really keep my temps. I installed Evo 3 factory hood vents during the winter and my car already runs on the t-stat with the fans on so I can't comment on hot temperature effectiveness from installing vents, but just from the initial drive comparison it takes 3-4 minutes of cruising before I reach operating temp with the vents as opposed to without.
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
Quoting GSTwithPSI:
Save the $300 bucks and just go to Home Depot if that's the route you want to go: click



lol



Besides, if I wanted to save money, why would I own this car? /ubbthreads/images/graemlins/smile.gif
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
Quoting tyeler18:
I live in the middle of the desert in AZ so I feel I have a fair understanding to the situation seeing as how I daily my galant in 120F as well as track it. I can tell you the fans are key. I have full working AC and it was 105F out today and I happily boosted along and sat in stop and go traffic at 185F with the AC full blast. I'm running a 1g mishimoto X line (3 core) which helps tremendously, a 180F t-stat, and I'm using a stock galant pusher fan and a stock 1g puller. It's a very tight fit and required a bit of clearancing, but the engine without AC on will hit 204-205 and drop back to 190F as soon as the fans kick on. If I have the AC on full (green light), fans on high speed all the time I can idle for hours on the t-stat. The fans are what really keep my temps. I installed Evo 3 factory hood vents during the winter and my car already runs on the t-stat with the fans on so I can't comment on hot temperature effectiveness from installing vents, but just from the initial drive comparison it takes 3-4 minutes of cruising before I reach operating temp with the vents as opposed to without.



The challenge with a 180T-stat here is the 80/20 rule. Most of the time, the stock 190 is fine. Running a 180 on the hottest days helps tremendously, but then I've got to start messing with the coolant offset to get the car into closed-loop. I'd like to keep the 190 in all year and just play with the airflow.

I'll build some shielding this weekend to divert air into the radiator. Jury is still out on the louvers, but considering I like the look they give the car, I might do them regardless of more data collection.
 
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