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

[DSMRevolution]

Ok so let me understand this. I am interested in creating a sort of 'cowl induction' for my engine. This would be done by raising the back of the hood up about .5 - 1.0". When people do this, do they usually raise the part of the hood that bolts to the hinge? Or do they raise the part of the hinge that bolts to the body? Either way I will need longer screws and washers. I think the part of the hinge that bolts to the body is actually studs so that wouldn't work. Has anybody done this on a 1g? I am going to try it then take another log and if it hasn't improved air temps then its going back to stock. I don't want to be a ricer for nothing Thanks and here is the picture that I promised:


Link to Picture...
-Credit goes out to xEM1x for this picture. PM me if you want it removed. Thanks

 

[Defiant]

As long as cars have been built, why do you suppose this isn't done by manufacturers? Just because they want to keep things away from us?
Chevy did it on a few cars, but it was ducted straight to the air cleaner.

Your intake is 'way up front by the grille.

 

[TURFNNSURF]

There is a rubber seal that runs along the top of the firewall, it seals the hood to the firewall in front of the windshield wipers. You can monitor your underhood temps for a day with this stock. Then carefully remove it to allow hot air to escape the back of the hood. I did this "free mod" and lowered under hood temps by about 5-10 degrees on average.

IMHO, building a heat shield around your intake & filter so it only draws air in from behind the headlight is much more effective!! I built a "test" heat shield around my 1g intake out of cardboard. When finished i took a test drive and logged the intake temps. On a 50 degree day my intake temp was 85 with the shield. Same day without the shield, intake temps were 115 to 125 degrees... 30+ degrees is a huge difference to me... Since the "test" shield of cardboard worked so well im using it as a template for a metal one...

 

[jtmcinder]

I have seen suggestions that you can create a "cowl induction" system by raising the rear of the hood before. Because my intake plenum gets very hot (partly due to it being mounted to the head [surprise, surprise] and partly because my IC heat-soaks so quickly), I did some experiments.

The idea is that base of the windshield is usually a high-pressure area, so creating a gap at the rear of the hood would allow in air. The problem seems to be that the rear edge of the hood is actually several inches in front of the windshield. Because of this - at least at the speeds I drive - air seems to come out this gap (when you remove the rubber seal), not go in. This can be seen in two ways: (1) tape a small piece of string to the rear lip of the hood and see if it flies out or gets sucked in, and (2) see if the air being sucked into the outside air supply is suddenly hotter.

Because the string stayed out and the air coming inside the cockpit got hotter, I put the rubber seal back.

But, note, that I only removed the rubber seal; I did not try raising the rear of the hood. YMMV.

- Jtoby

 

[Dieselboy]

Where did you get that sticker for your rear view mirrors??? Im loving that.

 

[DSMRevolution]

Originally posted by Dieselboy
Where did you get that sticker for your rear view mirrors??? Im loving that.

Oh that isn't on my car. Vinzdecals.com will make them though. He lives local to me. He does great work. Had him to decals for my old car and it turned out awesome.

Thanks for the information everybody. That is all very helpful. I am going to take a few logs today and then again tomorrow after raising the hood. I guess we will see what happens. I am very intereested in the heatshield idea too. This would be much more effective I would assume.

 

[Dieselboy]

Thanks alot, I emailed him regarding them. Those stickers are just to funny to pass up.

 

[98TsiAWD]

Thread moved to interior exterior forum.

 

[DSMRevolution]

Originally posted by 98TsiAWD
Thread moved to interior exterior forum.

Thanks, I wasn't sure since its more performance related and interior/exterior forum is appearance only.

Anyways I understand the theory behind it, just nobody answered my question about there you actually raise the hood from. Thanks!

 

[2FastTSiAWD]

I raised the back of my hood with some shims I had in the garage, and removed the rubber seal. I have not done any logging, but I do know that when the car is parked after driving, you can feel the heat with your hand coming out from back. I think it is a worthwhile project. and by the way, concerning manufactures doing a cowl induction setup, does any one remember the 69' camaro z28 and the 70 chevelle? That says something if you ask me.

 

[Streetbeat]

we did this on my friends 95 gst just by puttin washers between the hinge and the hood. this topic was discussed on here before and someone posted about about a honda that had this mod. the final results had extra heat over the intake manifold cause the heat from the exhaust manifold was blowing onto the intake manifold. id like to see some tempatures from before and after. either way its real simple to do.

 

[dsmturboawd]

the raised hood thing ive never understood. for all that its good for, it just doesnt seem worth it. i mean, it honestly looks like a poorly mounted hood.

 

[90DSMTurboFWD]

I always loved raised hoods, it gives the car a certain meanness to it haha. Its like hood pins, you gotta wonder....WHY wont it close?? hahah Nah i just love the way it locks.

 

[IMMORTALSPYDER]

Raising the rear of the hood is a common japanese mod. It's done to help heat escape while driving and works well.

 

[pboglio]

I finally found something that cures my high engine coolant temps, Redline's Water Wetter. I'm running an ADFX FMIC with a Spal 12" fan on the passenger side wired for constant duty. I tried Fluidyne's Radiator upgrade and that didn't help a bit, cruising temps in the 206-209*F after about a 1 hour drive. I pulled the A/C condensor/heat exchanger and that didn't help a bit either, still 206-209*F cruising temps.

Finally I dropped in a bottle of Water Wetter out of desperation, pricey at $10 but what the hell. Take the car out for a 1 hour drive, at the end of that hour my cruise temps were at a very consistent 199*F. The car is able to operate for long extended periods without heat soaking. Just for kicks I decided to see the effects on coolant temps by turning on the heater full blast. Looks like a 7*F temp drop from cranking on the heater full, which dropped my temps to 192*F cruise.

Aside from the observed 7-10*F temp drop (Redline claims 8*F temp drop), the biggest difference is that the coolant temps will drop fast from an idleing temp of 203*F and then after 4-5 seconds of cruising it will drop down to 199*F. Cheers.

 

[BoostinAWD]

Maybe your thermostat is set for those temps.
Did you try putting in a colder one say 180?

 

[pboglio]

Maybe your thermostat is set for those temps.
Did you try putting in a colder one say 180?

Funny thing is, my car runs better with the Stant 180*F thermo than a new stock 2g 180* thermo, even though the Stant thermo is crappy quality. I've done all the combinations of stuff; cutting holes in bumpers, pulling rubber insulation from the back of the hood, fluidyne radiator, removed A/C condensor. Only thing that made a measurable difference was Water Wetter. The stock 180*F thermostat will start to open at 180*F and be fully open at 203*F. So I'm around 199*F now which means the thermostat is still slightly closed at this point, I can live with that. What I didn't like was cruising around at 209*F which is way beyond the 203*F full open thermostat position.

 

[jesepes]

Why is your car running so hot to begin with?

 

[espinelli]

I run with a large front mount intercooler, condensor and expereinced the same issues you described. I did a couple things to fix my problem.

1. Removed the radiator and cleaned it. You wouldn't believe the crap that comes out of it.
2. Washed down the condensor. (Be sure to was Back to Front, same with the Radiator)
2. I used a couple products by prestone as well...Cleaner and Flush.
3. Replaced the thermostat w/ a stant 180
4. Have fun burping the cooling system. It can be a PITA sometimes.

This was last summer when my car was running. I don't recall what my logs read last year, but my water temps did drop and was very pleased with the results.

 

[espinelli]

Also, 180 is the stock thermostat temperature. You might want to consider a cooler thermostat as well. Stant also makes a 170* for our cars.

 

[Mirage2LTurbo]

I run a Fluidyne with a huge FMIC, oil cooler, and trans cooler all in front of the radiator, and I have trouble keeping my car at operating temp. It likes the low 80's, might get to 90 under hard driving. The fan only kicks on at 90. You might want to consider a new temp sensor, or look into other things like blown hg, coolant leaks, etc.

 

[FireyIce01]

something else you might want to try is drilling a small (1/8-1/16") hole in your thermostat, this allows small amounts of water to pass through even when the thermostat is closed without overcooling your motor like running without a thermostat would do.

 

[1stGenRocks]

Put the weather seal on the hood back. Especially the piece at the windsheild. The base of the windsheild is the second highest air pressure area on a car so opening it up doesnt vent the air from the engine bay instead it lets air into the engine bay which decreases the amount going through the radiator. The only time the vent at the windsheild helps is when you aren't moving it helps slightly.

I wish i could find the thread i read all of this in it but i think its gone. Basiclly any air that leaks in to the engine bay without going through the radiator is bad. 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

I will look for the thread about car aerodynamics since it has some good info but for now just let me know if you want me to writeup some more about it. This is the heavily condensed version for now

 

[pboglio]

...My car runs hot because of the FMIC. I like it too much to remove it. Before the FMIC I could run around 192-196*F cruise temps on a stock cooling system setup.

...I have a Stant 170*F thermo sitting in my toolbox, might give it a try.

...1g DSMs run cooler than 2g DSMs. Oil heat exchangers also shift some of the BTU load away from the water radiator, I've heard guys drop water temps by 5*-7*F that way. Thats my next project.

...I like the drilling idea in the Thermostat. I'll give it a try on my spare thermostat.

...I'll try putting the rubber seal back in. I've already used rubber bulb seal material to completely seal the radiator to the frame, the FMIC is sealed to the front bumper, and I have a custom aluminum duct sealing the the FMIC to the radiator with (2x) 2"x9" openings cut into the front bumper cover to feed the radiator directly. Its barely enough to feed the radiator and probably 4 times too small, but I like having my bumper reinforcement too much to ditch it and cut bigger holes.

...Once I get the cash, I'm going full carbon fiber hood with a carbon fiber hood vent.

 

[FWD98GST]

I had the same problem with overheating when I installed my FMIC.. When I went to RRE, I got the answer... Just buy the biggest spal fan they have and have it tapped to be on 24/7 when you have your car on, and I never heated again... just look at my pics on my gallery and you see my fan setup... I did every before from flushing the coolant, change my thermostat, radiator cap, you name it.. I did it, except buying another radiator.. hope this helps..