"Cowl Induction" hood setup help. Raising hood from hinges question. [Merged 5-9]

[DragGSX]

now im confused??? wouldnt removing the weather strip on the back of the hood release air in the engine bay quicker? thus kinda creating a suction in the front bumper. This is the real reason behind Cowl induction hoods

 

[98TalonTSi]

Air itself is not what's cooling your car. The transfer of air through a liquid heat exchanger is what's cooling the car. When the liquid reached a certain temperature, its circulated through the block.

 

[Defiant]

Did you try putting in a colder one say 180?

Thermostats don't cool cars. They keep them at operating temperature. More cooling area is what makes cars run cooler. Not thermostats.

 

[Defiant]

now im confused??? wouldnt removing the weather strip on the back of the hood release air in the engine bay quicker? thus kinda creating a suction in the front bumper. This is the real reason behind Cowl induction hoods

Cowl induction is for feeding engine intakes. They're at the cowl because it's the highest-pressure area on a car. Removing the rear weatherstrip will have the air coming in the grille fighting the air coming in from the back of the hood. Having the weatherstripping at the rear of the hood makes the air coming into the engine compartment draw out past the front wheels and through the space between the chassis and road. Leave it in there.

 

[92Talon251]

I recently installed a new radiator because my old one cracked. But I drove by Advance Auto I saw this product and I thought I would give it a try, with a 50/50 mix of anti freeze and water as well as Water Wetter I noticed a decrease in radiator temps with my ususal daily drive. At least by 6 to 9 degrees keeping my radiator temps in the range of 191 and 200 degrees. I have to say I was sceptical at first but Water Wetter does work. I cant wait till summer, I want to try a pure water and water wetter mix to see how low I can get the radiator temps.

 

[pboglio]

The highest pressure area on a car is not at the base of the windshield, its at the face of the bumper cover. I'd argue that you have 2 possible high pressure air inlets (bumper cover and cowl) and 1 lower pressure air exit (underbody). In reality, the rubber seal removal/addition had zero effect one way or the other on coolant temps as measured by DSMLINK on my car. Gotta experiment to see what works. I've got a few ideas on pressure reduction "behind" the radiator, and I'll post my coolant temp and pressure results when I get them. My goal is 192*F temps cruise, right now I'm a consistent 199*F.

 

[pboglio]

Built an airdam about 20" wide and 2" tall out of .015" thk Aluminum sheet. Bolted it below the front bumper underneath the intercooler. It dropped my coolant temps from 199*F to 196*F. Its not a duct or anything, just something to prevent airflow underneath the car. The odd side affect is that the knock counts went way the hell down, been trying to get rid of this pesky knock everytime the boost hits and just couldn't do it no matter what I tried. This airdam looks like it got rid of the high knock counts. Top end power went way the hell up, car is squating hard in 3rd gear. Don't know if its because of the increased flow thru my cold air intake, increased flow thru the intercooler, high ignition timing, etc. Looks like the airdam might have dropped the underhood ambient pressure. When I popped the hood the engine compartment was cool and I could actually could hold my hand near the turbocharger without getting a radiation burn. I'll have to measure the underhood air pressure using my Magnehelic Differential pressure gauge to see whats goin on, but it looks good so far. Cheers.

 

[slickster]

air dam pics?

 

[pianoman]

Yeah can you post some pics?

 

[FireyIce01]

as a bonus, a properly designed airdam, coupled with good sideskirts will help to increase your downforce using a concept engineered in the '70s called ground effect... minimal openings for air to get under the car from the front, and a larger opening in the back will cause the air to increase velocity to fill the opening at the back, and lower the air pressure enough to create downforce... early F1 racers (mario andretti that I can remember in particular) mentioned this made his car feel like it was painted to the road.... the downside being that when you did lose grip of the road, you were going a hell of a lot faster than before, and accidents were worse... it got banned after several years dominating F1... unfortunately with standard roads, and clearnace issues, you can't get your car low enough to be even 1/2 as effective as the one's they used in racing... and there's your useless fact of the day...

 

[Defiant]

The highest pressure area on a car is not at the base of the windshield, its at the face of the bumper cover.

The bumper face pushes directly against oncoming air, and has the top, sides, and bottom for it to escape from. The base of the windshield has the lead-in of the hood, and the reverse-knee of the windshield slope. You could get more pressure in a closed-bottom scoop directly facing the oncoming air, but in a simple semi-streamlined automotive shape, that corner's going to win.
Take your Magnehelic Differential pressure gauge and stick it (or, a simple water manometer) there, and let us know. I'd be keen to find out a hundred years of automotive practice was erroneous.

 

[pboglio]

I really like the idea of ground effects but my intent was strictly pressure reduction in the engine compartment to increase airflow to all my heat exchangers, NOT cosmetics or handling performance. If anybody notices, alot of the older mustangs use an airdam about the same size and location as the one I built, but made out of some type of black plastic. High speed air can be used to create a vacuum if something trips the air flow, like a 90* lip or airdam. Maybe its preventing spillage below the car and trapping it back into the Intercooler/bumper face, maybe its creating a low pressure zone behind it. Don't factually know yet until I throw the pressure gauge on the car to test it. However, if as an experiment I blow straight across the tubing on my Differential pressure gauge I get 10" H20 of VACUUM. I'm simply using the same concept to generate high airflow thru all my heat exchangers by tripping the airflow up and creating a vacuum. My radiator fan does not like pulling thru 2 thick heat exchangers, fan flow goes way the hell down. Lowering the pressure zone behind the fans helps out alot apparantly.

The front bumper face AND underneath of the car near the engine compartment both are high pressure zones, one is just higher than the other. I wanted high pressure up front and close to ambient inside the engine compartment during cruise conditions.

Remember, this thing is something I built in 5 minutes, totally a working prototype. Its made of .020" thk Aluminum sheet which is rigid enough to stand up to air pressure but soft enough to hand form over a 90* table edge and also collapse and not take the bumper with it if the car bottoms out. I'll probably buy the RMDSM bumper lip now that I know I'm actually getting an engine performance advantage out of it. Forgive the paint chips on my bumper, its seen 8 years worth of abuse.

 

[BoostinAWD]

Thermostats don't cool cars. They keep them at operating temperature. More cooling area is what makes cars run cooler. Not thermostats.

Oh really? Didnt know that

There is a reason why I asked that. Whos to say he didnt accidently have a 200 or similar in there? And yes I realize that. I don't run one period.

 

[L2RTSiAWD]

. You can also do ducting around the front so that there isnt as much turbulence caused by the fmic. You want the air to go straight into the fmic then the radiator without having any where else to go. Here is a link to a writeup on ducting a fmic on a 2G http://www.automotivearticles.com/Ducting.shtml

Either the pics are dead or it's my pc.

 

[pboglio]

The bumper face pushes directly against oncoming air, and has the top, sides, and bottom for it to escape from. The base of the windshield has the lead-in of the hood, and the reverse-knee of the windshield slope. You could get more pressure in a closed-bottom scoop directly facing the oncoming air, but in a simple semi-streamlined automotive shape, that corner's going to win.
Take your Magnehelic Differential pressure gauge and stick it (or, a simple water manometer) there, and let us know. I'd be keen to find out a hundred years of automotive practice was erroneous.

My line of thinking is this, purely my opinion and vastly oversimplified. Dynamic pressure is the result of kinetic energy dissipation. Without a velocity differential you have no dynamic pressure. Well how do you get a velocity differential? Well in this case by forcing the air to strike something or decelerating it. The greatest force occurs when the force is applied at a 90* angle or head on because this produces the lowest exit velocity, like the bumper license plate area. The force applied against the windshield has a rough relationship to the rake angle of the windshield. A thin verticle plate has the highest CD of all the shapes (i.e.~1.2), a horizontal plate the least (i.e. .01-.05), this is taken directly out of an experimental Drag coefficient test. An angled plate falling somewhere in between I'm sure. High dynamic pressure means high CD, which is what you want for heat exchanger performance. I'm saying its not necessarily the position on the car, but the angle of attack, leaving out the complicated flow dynamics going on around the car.

The air velocity exiting off the windshield in my opinion is higher than that spilling off the license plate for example, that means a lower velocity differential, lower kinetic energy dissipation, and lower dynamic pressure increase. I agree with you that the cowl area is a high pressure zone, which means higher than atmospheric, but I disagree that its higher than the license plate position on the front bumper.

I'm waiting on my 0-10" H20 gauge, my 0-100" differential gauge won't cut it for resolution. I'm actually curious myself what the numbers will be, its not entirely clear cut. Reason I say that is that I also have a cold air intake, which is probably mucking up the pressure zone underneath the hood.

 

[FireyIce01]

Oh really? Didnt know that

There is a reason why I asked that. Whos to say he didnt accidently have a 200 or similar in there? And yes I realize that. I don't run one period.

That's foolish... there's a reason for a thermostat.... otherwise dealers would have long ago found a way to not waste that bit of money in production... run a cooler temp thermostat... put a small hole in it to keep it flowing slightly even when closed... but you really should have a thermostat.... it helps get the car up the the ideal running tempurature to efficiently burn the fuel.

 

[pianoman]

What about having that deflector go all the way around the bumper, instead of just having it directly underneath the IC? Do you think I would be more effective? Or would you have too much deflection of the air?

 

[pboglio]

What about having that deflector go all the way around the bumper, instead of just having it directly underneath the IC? Do you think I would be more effective? Or would you have too much deflection of the air?

Its funny you mention that, I was just talking to "espinelli" about that yesterday. I'm sure it would produce better results. I grabbed the widest piece of aluminum I had. I think a 60"-72" piece of black thermoplastic, maybe extruded or something would be superior. It would wrap around the bumper curve easily. Being mounted 2-3" behind and below the bumper face and being black it would be nearly invisible, and using the stock lower bumper metal reinforcement bolt positions it could be mounted cleanly and securely. I was looking at the prices for the RMDSM lip, $160 + $35 shipping is a little much for a disposable item like a front lip.

 

[cbellsondsm]

a hood vent is a great way to go IMO it lets all the hot air out of the engine bay and allows the air to come off of the radiator and directly out, rather than try to find a way out of the bottom of the car, when cruising with a hood vent, it creates sort of a vacuum when the air is rushing over it and aids in cooling, thats how we solved the problem on a friends race car

 

[pianoman]

I think a 60"-72" piece of black thermoplastic, maybe extruded or something would be superior. It would wrap around the bumper curve easily. Being mounted 2-3" behind and below the bumper face and being black it would be nearly invisible, and using the stock lower bumper metal reinforcement bolt positions it could be mounted cleanly and securely.

What exactly is thermoplastic? I was thinking just some normal black plastic that is used for lining flowerbeds. Its about 2.25-2.5 inches tall but can be bought in many diffrent lengths, and is flexible enough to be formed to the curves of my front bumper but stiff enough that if secured right it would not flex while driving at high speeds. Even more so since no lip is offered for 1g's, but I wouldn't buy a lip anyhow. For the amout of abuse it would take Id rather make my own. Where is thermoplastic availble? Cost?

 

[thegreatms]

What exactly is thermoplastic? I was thinking just some normal black plastic that is used for lining flowerbeds. Its about 2.25-2.5 inches tall but can be bought in many diffrent lengths, and is flexible enough to be formed to the curves of my front bumper but stiff enough that if secured right it would not flex while driving at high speeds. Even more so since no lip is offered for 1g's, but I wouldn't buy a lip anyhow. For the amout of abuse it would take Id rather make my own. Where is thermoplastic availble? Cost?

In general it is a plastic that will soften when heated. Im pretty sure thermoplastic is simply a major (and one of the most common) types of plastic. If i remember it is based on the moecular structure of the plastic molecules. If you go on Mcmaster and look up thermoplastic you'll find 47 pages of it. here is the list of thing they consider thermoplastic:

Acetate & Polypropylene, Polypropylene & PVC, PVC, CPVC, Polystyrene & Extruded Acrylic, Extruded & Cast Acrylic, ABS, PET (Polyester), PETG & Butyrate, Polycarbonate, Nylon, Delrin, Acetal Copolymer, Polyethylene (LDPE, HDPE, VHMW, UHMW), Virgin PTFE, PFA, CTFE, Rulon, FEP, PVDF, Polyphenylene Oxide, Polysulfone, Polyetherimide, Polyamide-imide, PEEK, Polyimides, Garolite, & Phenolic

on McmasterCarr a 24" by 48" sheet .63 thick of abs is 20$.

but the flower bed stuff might work fine, nothing wrong with more home depot racing!

here is a good page on thermoplastic:
http://www.azom.com/details.asp?ArticleID=83&head=Thermoplastics+-+An+Introduction

I think the front air diffuser is a great idea. It will force more air up into IC and rad. and it will create a stronger low pressure under the car to help pull out air trying to leave the engine compartment. If you can make it flexible then it will bend rather then break when you go into steep entryway or drive up to a curb. If is is only like 20$ then you can replace after it gets too beat up.

 

[Zex4g63]

For those who are lazy or cheap you could rob a lower deflector from a 3rd gen camaro or firebird. They all have them unless it was ripped off.

 

[kazzam]

Living here in FLorida, it gets damn hot and turbo cars don't like it one bit. After my front mount install, my car would overheat like crazy. It would be ok if i take it easy but as soon as i start getting on it, it will heat up.

I first cut my bumper so more air will flow to the radiator. I realize not many people would do this. But, i don't think it was critical in the whole thing. I also removed my AC condensor. These things are HUGE and block the radiator completely. You could try this instead of cutting the bumper up.

I then went ahead and switched my driver's side fan to a spal 12" fan and rewired it using a relay to turn on whenever the driver's fan turned on. All together I had 2 trigger wires for both the speeds on the main fan. I suggest you look at a relay diagram. It is pretty easy to figure out. I believe the fan helped a lot, but the stock one should have done the job. A simple re-wire would be good. Also, i pulled the power wire for the new fan from the battery terminal. This would garantee the most current for when it is needed most.

I then went ahead and removed the rubber liner that is right near the bottom of the windshield. It is about 1/2" thick and makes for big place to dissapate heat from.

When the car warms up, i can put my hands near the ednge of the hood (near the glass where i removed the rubber from) and feel lots of heat coming out. When both fans kick in, there is a lot more heat coming out of there. Also, standing in front of the car with both fans running, i feel suction through the front of the car. BTW, the rubber liner can be put back because it is held by plastic pins.

I took my car out and beat on it pretty hard. My temps didn't pass 205f.

I hope someone finds this beneficial. I been trying to fix this for a while now. This finaly worked. If it didn't work, my next step would be to buy a fluidine radiator.

peter

 

[Syndicate13]

I also live in FL and I would never go as far as to remove my AC. It gets damn hot. Here we can also get by running much more water than in other areas. I suggest getting a new thermostat if yours hasn't been replaced and flushing the coolant system. With those things done and my fans set to run all the time I regularly run around 196-203 w/o AC.

 

[Defiant]

I then went ahead and removed the rubber liner that is right near the bottom of the windshield. It is about 1/2" thick and makes for big place to dissapate heat from.

The base of the windshield is a high-pressure area. Whatever can leak down from there will serve to interfere with air leaving the engine bay, which goes out the bottom as the surface of the road helps to pull it out.
Replacing that seal is recommended, for better cooling.