I we let others answer regarding the holes specifically, but I want to add my opinion too.

Having the whole cowling removed has no disadvantages other than appearance and losing the windshield sprayers.

 

Nope no negative effects. The cutouts really aren't that visible at all. I find myself always pointing them out instead of someone asking what they are.

 

anyone removed there cowl and want to sell or trade? mine was cut for the air mod, i am in so cal

 

Finally got around to this getting ready for a big trip. Used the blowtorch + butter knife technique, finished with razor knife. Butter knife took out the back side very quickly, then 1/4" to the interior of the front squares, trimmed w/ razor knife.

 

A quick question for you guys, are any of you putting any sort of mesh like rain gutter mesh to help keep leaves and such out? It'd probably wouldn't impede air flow and as well would add a bit of protection from stuff like mice getting into the engine bay.

 

These holes were cut using a 1 1/4" hole saw. Measure the spacing out and mark it before cutting it so the spacing and placement is perfect before cutting the holes

It is easy to add the sceen mesh to this mod. This is plastic rain cutter screen mesh from Home Depot. I used a two part epoxy to glue it on.

I need to remind anyone that is going to do this cooling mod that you will lose your air-conditioner outside clean air useage. You can turn on the recycled air but it will still pull in some air from the outside. When you do this mod the engine compartment air goes straight into your clean air opening for your air-conditioner.


Cooling Mod by Jaster2, on Flickr


Cooling Mod 3 by Jaster2, on Flickr


Cooling Mod 1 by Jaster2, on Flickr

 

^very nice!

 

That mesh looks good, will have to give it a try.

 

Did the left half*not the wiper side* today. Started out real nice looking, but i ended up getting hasty and said screw it so its a real nice hack job on the opposite end i started. But i dont think anyone will notice really so. Also took the hood insulation off as well. just need to take my bumper off to do the front grills, and then fit my fog lights in :|

 

Why will you lose the outside air option if all you're doing is drilling a couple of holes?

 

OPel THANKS for all this info ( to everyone else as well) even tho I know next to nothing about cars but will be getting a TL in a few months! You guys are truly the best I stay up hours just reading BEST FORUM EVER!!

 

Apple Inc. Perfected That lol!

 

The cooling mod actually opens up a direct route for engine compartment air to go straight into your clean air opening for your air-conditioner. It really is the only drawback to this cooling mod but it is one to be heavily considered before proceeding.

Posts 153 and 299 by the OP give you a visual of the clean air opening for your air-conditioner.

 

Jaster,

Thanks for reminding us of the clean air intake. I was just about to do this mod today and will be delaying it until further clarification as I use the clean outside air 99% of the time.

On post 299, Innacurate stated that you could cover the clean air opening with foil tape. Does this completely resolve the clean air issue?

 

Yes, the major down side of this mod is the loss of outside air. It took a while for me to get use to having the recirculate on all the time. The car will switch it off when the windshield defroster is on, so you have to remember to switch it back on.

I never use the WS squirters so the loss of them has no impact on me.

 

We still lose washer sprayer ability with the cutting of the cowl? I thought since we are not removing it, we wouldn't be losing it.

Also, if we only cut out the center portion like post #364 above do we still need to cover up the air opening to keep rain water out? If not, we wouldn't lose the clean outside air for the ac option either, no?

 

I was thinking of the full cowl removal. Part of the issue wether you do a partial of full UCM is the hot and stinky air coming from the engine compartment into the car. Stock the fresh air intake area ( the cowl ) is sealed off from the engine compartment for this very reason. Once you break that seal by letting heat from the engine exit thru the cowl area you are now exposing your fresh air intake to the air coming thru the engine compartment.

 

If you are only cutting holes in the cowling then there is very little worry about water getting into your clean air vent hole for the air-conditioner. If you do any of the cooling mods you will lose clean air because of the direct line opened up from the engine compartment. Anyone wanting to see if it is something that might be a bad thing running only recycled air-conditioning should first do the Ultimate Cooling Mod (remove the entire cowling) first and drive around for a week or more and see if it is something you can or cannot deal with because if you do not like it then you can just put the cowling back in place and nothing has been cut up yet. I drove around for a month with the cowling removed first before I decided to cut into the cowling.

When I did my Semi-UCM version I cut the holes up a little bit higher so the water had more of a ridge to stay out and not pour straight down into the area of the clean air opening as seen below.

By the way, the Ultimate Cooling Mod by far releases more heat from the engine bay. It makes for a great hand warmer during the winter when your pumping gas at the station. Oh, one other thing I forgot to mention. You also hear a LOT more intake noise from any type of cold air intake. I had a short ram intake and it was shocking how much louder it was with the cooling mod. When you hit the VTEC it was an amazing sound (good or bad to someone).

I did all of the above to my previous Honda Accord V6 but I will not do it to my TL-S only because I have found that I just like having fresh clean outside air-conditioning to much. I now feel that only someone seeking the absolute most performance from their car would be happy with the UCM in the long run.



Cooling Mod 3 by Jaster2, on Flickr

 

That's great to know, man...thank you both. I will likely just end up cutting into it and putting in the same little gutter coverings to keep leaves from going in. That looks about as intense as I'm willing to go. I've noticed that when I drive my car at noon for lunch, it feels SUPER sluggish, so I'm SURE this will make a big difference. Either way, if I ever want to go back, I can live with paying $130 for a new cowl.

 

After reading through this thread from start to finish I decided I'd try my own version of it. I was not willing to NOT have the cowl, so full UCM was out. And I did not like the drilling, cutting, hot butter knifing of the visible side of the cowl. After removal of the cowl and with some of my HVAC knowledge for homes, I realized a few things.
1) Pressurized hot air will find an escape route (try popping open your airtight coffee mug with boiling water in it after it's been sitting closed and you'll see).
2) Air always takes the path of least resistance. So whether the grills face forward or backward, the hot air will make it's way out.
3) Big in doesn't necessarily require a big out. With the vents cut open on the under side to allow the escape (like all the other versions), I believe the hot air will go out of the stock openings on the cowl. Especially once Inaccurate stated that most of the heat dissipates out of the middle section of his cowl area anyway (or no cowl area for him)

So, I cut the openings in the underside, which will not allow rain water in and up and under and into the air intake for fresh air for AC. Obviously, I kept my wiper squirters and visibly you won't see a thing. I did get a little ambitious with the dremel routing tool I used (looks like a drill bit but allows you to use sideways movement to cut) but you can barely see where I cut into the grill. I also opted to leave the rubber seal that runs the length of the cowl off...no sense in making it any harder for the air to escape...if there's a 2MM gap along the length of upper hood, that'll allow the heat out too.

That said, did it, reinstalled and drove around until the engine got up to temp. Then did a few high speed passes around the neighborhood...got home and touched engine, just barely warm. I am convinced, even my baby version works! Does it work as perfectly as UCM, I'm sure not. But to me, it does allow me to keep all functionality and looks and get some of the reward. I also removed all engine covers. Let the air flow...

Also added some aerospace 303 to the cowl, figured it was a good time.

I also have a k&n drop in filter and no intake resonator.

See, here are all the stock grills for the fresh air recirculator. In addition, I ran the ac with recycle and fresh air and no scent of engine or gas or anything


Another tip, wiggle the base of the arm back and forth to get it to come off and mark where the wipers sit before removal. I also marked passenger side to avoid any confusion:

Here's the seal I opted to leave off in addition to all engine covers

Here's the bay and what you can and can't see.

And here's my temp reading after driving it hard for 10 solid minutes after the engine temp being warmed up


I'm happy...and this is likely as far as I'll go with the UCM mod. I always felt like maybe I was crazy but the car felt like Jek and Hyde when it came to how it drives when it's hot out or not. Now, it should be resolved enough to feel good all the time.

 

I'm wondering if there's a way to further modify the cowl by creating a funnel that separates the engine air flow from the clean air intake. Are there one or two clean air intakes?

 

One.

 

^^^ thanks bud.

So to have the best of both worlds, we'd have to block the engine air from flowing over to one side of the cowl. I don't know enough to comment if this is possible, but if it is, it might not be that difficult as the seal wouldn't need to be airtight.

Perhaps someone with experience chopping cowls can chime in.

 

No problemo, man...well, to be honest, in looking at the design, even the totally stock cowl didn't separate engine air from outside air to be routed to the intake for fresh air for AC. IMO...this is relatively moot...you can do the mod how I did and use the oem venting in the cowl as much for hot air extraction as for fresh air intake.

Untested, of course...just theories but I think I'm on the right path.

 

Ok, so in 2 years of having this car, the best mpg I've managed is 25 on highway trips. Today, I took an over 100 mile drive and managed 27 with an average speed of 75. Is it possible that this mod helps with mpg?

 

Yes, it is plausible. The cooler underhood temps will make the IAT sensor read cooler temps. Cooler temps means higher ignition timing. Higher timing means better MPG and performance.

 

Well I appreciate the pioneering and for the many improvements you've pushed us all to make

 

i'm glad this was visible. i didn't want to read 400 posts looking for this lol.

i'm gonna do this to mine. i previously did something similar in my old car and it made suchhhhhhhhhhh a difference.

 

FWIW, I did the partial UCM a while back and have been using the fresh air intake with no side effects other than some smell when sitting in traffic.

 

Is it just me? In Sofla it's so hot the ac doesn't really feel very good and cold unless I do recycled air only. I BARELY use the fresh air...only when on the highway when I have the sun roof open drawing the air thru...which I wouldn't smell gas at that time either!

Thanks for sharing, regardless though.

 

Sure thing, I've noticed that if the recirc is on when I start the car, if I turn it off the air stays cool. If I start the car with recirc off, turn it on, then off again the air gets hot...no idea why?? Normally, recirc on/off feels about the same...just smells diff. I love being able to sit at the drive-thru window and watch the heat waves leaving the engine bay!

 

my AC also sucks. there just isn't enough fan speed without the recirc on IMHO

 

Dang...hot day and went out for lunch...intake was 145. I guess my little cooling mod only works when I'm going fast and forcing the air through. It doesn't just find it's way out.

 

I didn't think yours would do much on a hot day. Remove the whole cowling tonight if it is going to be a hot day tomorrow and take another temp reading tomorrow.

 

Yeah, I guess not. No, I'm not willing to ride without a cowl so there's no point in even going on the mission. I won't can't lose the wiper nozzles and I am vain when it comes to the car looking good as well as performing well. I'll just consider what I did as a little HELPER in getting the hot air out, but not a permanent solution.

 

Just take it off for a day and take the same temperature reading under the same circumstance just to see what the reading will be. If it is close to what got then you will know that your small version of the UCM is working. You already know how easy it is to take of the cowling. This way you will know and your findings will also help out the next guy reading this thread.

 

Customize your own hood spacers. Works like a charm for under $5!

 

I just hate how the hood spacers look...moreso than the lack of a cowl!

Jaster, you are right. I will give that a whirl. Maybe the 100 degree heat is the real culprit here...maybe the mod only works up to a certain point in certain climates.

 

good reading here guys...i think i know what i'll be doing next.

 

indeed...what version you goin for?