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"Rice Over Greyforest" bumper mod for cooling...and great results!

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Rice Over Wheat

15+ Year Contributor
1,959
5
Jan 24, 2004
Winter Park, Florida
[EDIT] This thread begins with radiator vents and progresses into several other mods to create an engine climate control system where engine temperatures are regulated according to ambient conditions. Anyone with overheating or cooling system inefficiency problems can benefit from some or all of these mods, with results varying accordingly.

Ok, here's my latest attempt at getting my engine temps as low as possible. That's why I posted it in this section. I was looking for a way to open up my bumper like the Evo, 4G, Sti, and basically every other late model sporty car has. But I wanted something to match my Greyforest hood mod. So here's what I did...I added matching ram air vents in the bumper!

Basically I just took Greyforest's template and made it larger and a little elongated. Drew in my pattern with pencil and took a dremel to it with a metal cutting disc. Then I rounded the corners with a steel cutting bit. Finally, I just added door trim to make the edges clean. About 1.5 hours to do.

I thought about adding some wire mesh but I think I'm going to keep it open. I want maximum flow. If you look at the 2nd pic you can see that the air can flow straight above my fmic and through the a/c condensor and radiator. That thing on the left in front of my condensor is my 2nd tranny cooler (yes I have two). I believe this will be very effective. I also believe that it will enhance my hood vents to be useful at cruising speeds as well, since the air has a path to flow straight through the front and up the top, as well as below the car.

Tomorrow I will be opening up my front bumper to expose the top half of the intercooler and I'll post pics of that when I finish. I know the looks aren't going to be to everyone's taste, but I really like it and it is functional first, looks second.

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kevin, do you have aim, or better yet a phone number? I want to do this mod to my 1g, id like your assistance, maybe I could stop by your house Friday or Saturday? I dont have the necessary tools to do it myself so im wondering if you could lend some help. Lemme know wuts up.
 
I considered lateral slots in the bumper like many people do, but I didn't think that would go well with a 2Ga bumper nor match my hood vents. Also, I don't think they offer as good air flow as these vents.
 
It's just my opinion, but I don't really like the looks of it ;) It might be a bit more functional if you had a downwards dam to the IC

I think a more functional and appealing mod would be to get rid of some of the sides of the smile in your bumper. The extra area outside your IC gives a route for the air to go around, and you want as few of those as possible. It also looks way cool (kinda like on the evo's) when the whole grile is IC.

It's starting to look like a WS6 Trans Am!!!
 
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Oh no you didn't!! OMG ROFL

You guys are killing me, 0/4 like it? My neighbors like it. It looks better in person. Notice the corner shot makes it look best...frontal pics don't do it justice. Looks clean in person.

In august I am doing a 2Gb conversion and new paint job anyway, so I don't have much to lose by experimenting. And btw, while the 2Gb has a taller opening, it isn't as wide as a 2Ga so you then have the opposite problem of blocking airflow to the fmic.
 
Eh...if you don't see the point of more airflow to the radiator bypassing the fmic, well... WTF

Btw, I went cruising around and my intake temps appear to have dropped 10 degrees and significantly reduced my knock on hard pulls. The flow through the engine bay and removal of hot air has greatly improved while the car is moving.

I need to cut the front bumper to clear 3 inches blocking the upper half of the fmic. Should I make the opening oval or simply enlarge the "smile" 3 inches up top?
 
Btw, I went cruising around and my intake temps appear to have dropped 10 degrees and significantly reduced my knock on hard pulls. The flow through the engine bay and removal of hot air has greatly improved while the car is moving.
That's all that really matters.
Maybe it's just the shape of the holes, but it just looks like a huge pig's snout to me.

I need to cut the front bumper to clear 3 inches blocking the upper half of the fmic. Should I make the opening oval or simply enlarge the "smile" 3 inches up top?
I vote for the oval. Get rid of the nostrils.
Besides, I think the overheating issue would be better addressed by directing more air around to bypass the intercooler and flow toward the radiator.
 
HAHAHAHA! See, they are twins!

Btw, I went cruising around and my intake temps appear to have dropped 10 degrees and significantly reduced my knock on hard pulls. The flow through the engine bay and removal of hot air has greatly improved while the car is moving.

No matter how it looks, it's a great mod, congrats!
 
That's all that really matters.
Maybe it's just the shape of the holes, but it just looks like a huge pig's snout to me.


I vote for the oval. Get rid of the nostrils.
Besides, I think the overheating issue would be better addressed by directing more air around to bypass the intercooler and flow toward the radiator.

Hehe it does look like nostrils, but there's not many ways to open up the bumper at that spot above the fmic without doing so. Plus you have to maintain some structural integrity so the bumper still had support. And there is no closing of the nostrils, those are there to bypass the fmic so the radiator gets direct flow...not to mention I can't uncut it. LOL

As for more flow to the radiator...the only thing I'm worrying about with an oval mouth is if I start looking like this:

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I noticed that the 4G eclipse has a similar front air vent setup. And it seems upper air vents are what engineers are using for optimum cooling to the radiator:

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2005 Sti

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Evo 8

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Ok, here's a new pic of my front bumper finished. I enlarged the "smiley" to a full oval opening by cutting out an additional 3 inches. Now almost my entire fmic is exposed to direct air flow...only a 0.5" margin remains on top and bottom covered by the bumper. Also, I cut out the diagonal arms from the upper bumper support that you could see in the earlier pic. Now my radiator has direct air flow. I also added a cold air box and opened up the sheetmetal under the filter so the turbo draws only ambient outside air.

My results are simply AWESOME! I drove around for 30 minutes at around 60 mph with fans OFF. My intake temps fell 35 degrees to 79F, and my engine temps fell 25 degrees staying between 160F - 165. If you have dsmlink, I attached a log so you can see for yourself.

I also registered a very significant reduction in knock thanks to the low intake temps. I am very very pleased with these cooling mods. Now I can start tuning my car since I have completed my cooling system upgrades. If you're curious what I did to get my temps as low as they are now...here's my laundry list:

Hood vents
1650 cfm SPAL main fan
810 cfm SPAL a/c slimline fan
Koyo radiator
Thermostat eliminated
1.1 bar radiator cap
Bumper radiator vents
Bumper opened for full fmic exposure
Cold air box w/ sheetmetal cut under filter
70% water 30% coolant, 2 bottles water wetter
DEI heat wrap: 2g exhaust manifold, 02 housing, dp

http://i31.photobucket.com/albums/c357/stylepts/Bumperairvents.jpg

http://i31.photobucket.com/albums/c357/stylepts/Coldairbox.jpg
 

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200-206F...but I like to run a lot cooler than that because anything higher than 206F and the ecu pulls timing. Also, hot engine temps makes for hotter intake temps because your ic piping after the fmic and your intake pipe get very hot. Intake temps higher than 100F and ecu begins to pull timing.

My goals are engine temps under 200F and intake temps under 115F under all driving conditions in Florida.
 
I think I'd make the two holes in the bumper a bit longer and that will increase flow and look alot better, Dont cut up just over that way your bumper is still attached and If you notice all the cars you posted pictures of have bigger holes on the side. Great results though.
 
Here are more results. I was driving around today at 1pm EST to see how my temps would be during the day. Last night's log was around 11pm. I also wanted to see how low my temps would be with the fans ON. Results:

Intake temps 87F. Engine temp between 143 ~ 150F!! Radiator vents are extremely effective. You basically render the downside of having a fmic null, because air can feed straight through to the radiator.

Zack, I had considered something like that but the problem is that the center frame support beam and upper bumper support is in the middle there which not only blocks air flow but also looks like crap. And you can't remove it or you have no upper bumper support. Plus, my belief is that my air vents match the factory side air scoops on a 2Ga.

Geoff, I'm running no thermostat because my 180F one became stuck open and I didn't like any of the other thermostats I tried, including a 170F and 160F. They begin to open at those temps but don't fully open until my temps reach around 190. Instead of drilling the T-stat for more flow I decided since it is FL I don't really need one. I just keep my fans off while the car warms up and I don't get hard on the throttle until then. What I'm doing is basically preparing my car for the summer heat and 100F ambient temps.

Here's a couple more shots of my bumper completed. Oval mouth.

http://i31.photobucket.com/albums/c357/stylepts/Bumpervent2-1.jpg

http://i31.photobucket.com/albums/c357/stylepts/Bumpervent1-1.jpg
 
Where did you get that 1.1bar radiator cap from? and hows the quality
 
Thanks, it's growing on me. And apparently some people are intimidated by it. Today I was driving to the gym and a RSX Type S did a ricer fly-by. I don't street race anymore (it's a criminal misdemeanor in FL) so I ignored him. However once he saw my front end and the light turned red way ahead of us he full on blew the red light interrupting the other traffic direction. I guess he didn't want to be at a light with me. :rolleyes: That's the bad part about these cars...it's like a magnet for idiots, even when you're just trying to get from point A to point B.

Where did you get that 1.1bar radiator cap from? and hows the quality

Local guy I know had an extra. I think he said he got his at autozone or advanced, forgot which. Should be $15 tops. It's 15 psi compared to stock .9 bar / 13 psi. I believe, don't quote me, that for every 1 psi of pressure you raise the boiling point by 10F.
 
I dont like it, it looks horrible but i give you an A for effort and an A for making the cuts clean and matching.
 
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