cool, you could attempt to do some hood spacers, there'es a couple of ways of doing that.

you can also wire in a switch to control the fans from inside the car, and override the ecu for when to the turn the fans on.

Well I got some new temps taken from the same time in the morning to compare to before the mod was complete. I noticed today that the thermometer will pick up heat wash from other engine parts and the closer the thermometer to the piece being checked, the more accurate the temps. Thats explains why I got a higher reading after the mod was performed and a not so tight of a grouping of temps. Now for the more accurate temps.


After car has warmed up completely- around 730am





And after the same drive time around 745am




BOTTOM LINE- Well there definitely was a reduction in temp now. After driving the car there was about a 30 degree difference where the coolant flowed and about a 10 degree difference where the intake connects. How much of a difference there will be after lets say, an hour drive time I hope to find out soon because of the heat wash from other parts.


My next modification to test will be the hood spacers. I read today that someone has also taken temps to see if the hood spacers actually lowered the engine bay temps. And to there surprise and mine it actually raised engine bay temps. He did not say how much he raised the rear of the hood, but that could be a factor

5 mins of time for a 20 degree difference? worth it!

how about an intake wrap or hondata intake manifold gasket?

You could use your A/C Condensor to cool you engine bay instead of your cabin.  This would take a shit-ton of work but would put your engine bay temp BELOW ZERO.  Drill out you motor cover and run steel line through the cover and replace your stock lines with the new lines. Use your in cabin A/C controlls to trigger the fun.  You will lose power by running the A/C off the Fan Belt, like usuall, but the temperature difference would make up the lost HP and some for sure.  If you want to get crazy, you can try to run your A/C condensor off of your radiator fan to keep the CS from running your A/C. This would turn on your A/C when the engine bay got too hot, and you would give controll of the system to the vehicle instead of you in the cabin, but i'm almost possitive that wont work, since those fans hold almost no resistence.  I've been thinking about this idea for a few months, but I am not even close to knowledgable enough in A/C components to try it. Go for it, and let me know if it works!

Well here is an update. I tried 2 different hood spacers. The first one is just a nut put in between the hood and latch. The second one I made and is about an inch in size. They are just like the ones someone used to sell on this forum. I can write up a how to if people are interested (well worth it, read below). Now some variables. The temps were taken during the same time of day on different days, in the same order. The car was left running while the temps were taken. The route was the same 12 mile route on my way to work. Now for the pics


The control numbers (no modification)



After the "nut" spacer





And an easy way to read it



I couldn't really think why the temps would go down in some places and up in others. My only guess is that the heat in the bay could move out of the engine, therefore allow newer heat to build up, but slow enough to heat parts on its way out. That is my only guess, I am not a scientist that studies thermodynamics (i think that is what its called)

Now for the hood spacer, about 1 inch





And in simple terms



As you can see, there deffinately was a great reduction on the engine bay and well worth the 11 dollars I spent making the hood spacers.

Now for the downside of the hood spacers. It rained recently and pretty hard, I am talking tropical storm like rain. The car was sitting outside my work for about 45 mins in the rain, then I drove it home and looked under the hood







The foam on the intake is wet on the side nearest to the fender.

My next mods are going to be the fan control switch and I am looking into a heat shield for the intake and fuel lines. And as far as the running the AC out of the cabin, I am not going to be trying that mod, living in Hawaii its nice to have AC sometimes.


Oh and by the way, I have lowered the throttle body by 33 degrees.

I thought about it as soon as I seen that water on there. Now I just got to find some black tubing

SPECial Sauce wrote:

You have convinced me... I have put this mod off for years.  It'll be done before the weekend.  Nice hard data finally... good job.

If you do the TB bypass, you need to get that insulated intake gasket or youll crack shit when it gets cold here. Also, after you install the gasket, and drive for a while, the intake manifold will be warm to the touch and wont burn you like it will now.

Awesome man can't wait to get back and check this shit out. I want to see what the hood spacers look like in person and I might try them out.

"If you do the TB bypass, you need to get that insulated intake gasket or youll crack shit when it gets cold here"


True, but I dont have that problem, but it is good idea for those that live in that type of climate



As far as the throttle body bypass mod, do a search for it there is a thread on here already that shows you how to do it. Its extremely easy, only thing is expect some coolant to leak out. Nothing a little cleaning cant fix. And I will make a "hood spacer how to" sometime this week. Another easy mod, just got to use your man muscles


"Awesome man can't wait to get back and check this shit out. I want to see what the hood spacers look like in person and I might try them out."

When do you get back? I may not be here, I leave in October for 12 months


The hood spacers are a love it or hate it kind of thing. I myself like the way it looks, some people dont like it. But thats why it is on my car and it serves a purpose besides looking sexy

Last edited by youknow (2008-07-17 02:46:05)

Damn I get back in September. But hey I will try to get some of it done before you leave so I can continue it while you are gone. To see how much you can lower the temp inside the engine bay. Some of the stuff I plan on doing is Ceramic coating header and maybe the midpipe, Mostly to prevent rust and stuff.

Porthos where can we go here in Hawaii for coatings?

Dude nice thread. I have been looking into this but for different reasons. My theory is the more power you make with the same fuel flow into the engine the better the economy will be.

So my first attempt was late last summer when I bought my nismo evo2 CAI and intake insulation wrap from DEI products. Well during the winter i shot my theory to hell when it got cold out the ecu saw this temp change in the MAF and thus put more fuel into the eng to compensate for the increased air density and thus MPG went down.

Oh well my point is the cooler the intake charge will give you more power but you will suffer worse MPG.

One thought I had was to seal off the hole where the tube for the CAI went into that area behind the bumper as to not get any hot air from the engine compartment.

Another was I saw something about twenty years ago in the computer industry that would help me decrease the intake air. It was called a peltier cooler. it is basically a mini refrigerator that cools a heat sink to the point of frost would collect on it, this attached to the intake tube either on the inside or the outside should cool the air quite a bit. but when looking into the cost effectiveness it didn't make much sense sine it takes 10 degrees F. to make 1 HP. I kind of gave up hope. hope this might help you in your quest. any questions just pop me a PM.

Good Luck and I will keep checking in on the post for future accomplishments.

i read an article in the August issue of import tuner  and they tested out diferent products.(granted they were not done on a spec but im sure results would be similar)
thermo-tec insulating turbo
heatshield between engine and intake manifold
upgrading radiator fans(mishimoto)
nitrous express  ntercooler
thermo-tec cool air tube heat shield
and   S-max cool can
they all cooled engine temps while increasing HP

and they also had a article on product called water wetter  which when they tested it decreased temps by 13 degrees

not sure if any of this will help or was already said

Well I just got back from a month of training and picked it back up. I installed the cooling fan switch, picked up a coolant gauge, 170 degree thermostat (for when I go boosted), and an indoor/outdoor thermometer to measure intake temps.



I saw this on a Supra, he put it on the cold side of his intercooler. The only thing he suggested is to superglue the sensor to the piping so it doesnt get sucked into the engine. I glued mine to the last pipe that connects to the throttle body. That way I can get a true temp after the air has flowed threw the whole tube. I also ran the wire outside of the pipe and placed the coupler over the wire, that way if the sensor somehow does get detached from the piping, the wire will not allow it to go into the engine. Then I just ran it into the cabin and put it in my cup holder.


Now to try out the sensor with a free mod. Remove the foglight infront of the intake filter. Here is the results

Foglight in after my usual driving strip

filter temp-85.5
When the pipe first enters the engine bay- 90.5
Right before the water bypass on the intake- 94.5
Where the intake meets the throttle body- 109

After about 30 mins, I took out the foglight and drove back

filter temp- 85.5
When the pipe first enters the engine bay- 79
Right before the water bypass on the intake- 80.5
Where the intake meets the throttle body- 98.5

Now for the pretty picture (dont mind the messy engine bay, the pic is from before I cleaned it so I could do a before and after for my friend to see)



As you can see it does decrease temps. I have been driving around with mine out for months now and have had no problems (even in the rain), just got to clean it more often.



Now lets think about this. It is a fairly common belief that if you can lower your temps 10-11 degrees, you should see roughly 1hp. Nismo intake- 281 and makes 8.7hp (as per the advertisement). Thats 1 hp per $32.30. I removed the foglight and saved roughly 12 degrees (about 1 hp if that theory is correct). The throttle body bypass mod, also free, saw a reduction of roughly 20 degrees (about 2hp). So in theory I just made an extra 3 hp for free doing those 2 mods.

Now I am planning a intake wrap/heatshield and am going to test that out. I lost the numbers but before I left I wrapped my intake with aluminum foil for haha's. I actually saw a decrease in temp, but I also ran a longer test and it showed that it actually increased the temp on the tube. I believe the reason for this is because the foil blocks the radiant heat from the engine, but after a certain point the heat wash from the engine works its way threw the manifold, then throttle body and into the tube where the foil then acts to keep that heat in the tube. Now bear in mind that the aluminum foil is just that, foil on both sides. I found some reflective wrap that has foam on one side which should help prevent the intake from "cooking" itself by reflecting the heat back into the intake as the foil did.

i havent found an actual writeup of the bypass mod that makes sense...people just took pictures of the final product..and just gets me angry..might have to try this today.

so this is the first experiment that proves the tbb actually is worth the 5 mins of time. all ye haters should read this

So do you think that something like the DEI exhaust wrap around the intake would prevent heat soak? Or would it insulate it and make it worse? I have seen it done on a few cars but since it is meant to keep heat inside the header and out of the engine bay it would keep the radiant heat from the engine from getting to the intake but then again it might hold in the heat.

Oh yeah, I am making a heat shield instead of wrapping the header

I'd like to see more on this.  I have considered cutting/beating/molding the stock heat shield to conform to my Nismo header, but figured it was not worth the trouble...