PDA

View Full Version : Any reason I HAVE to run a center hood latch?



Steve1968LS2
01-14-2006, 06:23 PM
I am running these hood pins:

http://www.aerocatch.com/automotive-home.html

I now have them and the design is VERY stong.. so much so that I am thinking of ditching the factory hood latch.

I will keep the braceing but cut away the mechanism part. I will also not have the latch parts on the hood (fill the holes)

I ordered the new DSE Closeout and I am thinking of welding up the center area. This will force even more air through the radiator. It will also have a very clean look.

Anyone see any flaws in this plan. The two hood pins should be strong enough or am I missing something?

Thoughts.

protour_chevelle
01-14-2006, 06:56 PM
Make sure that air can get out from under the hood.

-Matt

Steve1968LS2
01-14-2006, 07:26 PM
Make sure that air can get out from under the hood.

-Matt

Cowl induction hood makes a good escape route.. I would love to have extractors like the Mule but that's a bit out of my price range.

protour_chevelle
01-14-2006, 08:57 PM
Cowl induction hood makes a good escape route.. I would love to have extractors like the Mule but that's a bit out of my price range.

Wasn't sure if it was cowl or not. My buddies 55 Chevy was having problems with an open grill at 162mph in the 1/4. The front was trying to lift because the air had no where to go. They had to cover up the grill and the problems were solved.

Do something fancy with your fenders lol. Kinda like the GrandNational gang.

-Matt

Jim Nilsen
01-15-2006, 11:31 AM
Hi Steve, I have mine in the pile of parts that won't be going back on the car. I have my hood going the other way now but it is something that I believe you could live without. If in doubt you could leave the safety latch on since it doesn't weigh that much and is what makes sure the hood stays down if the main latch fails. I too have had a hood fly up on me once and that is why I turned mine around.

I am also a firm believer that air has to get in to get out and restricting the air inlet size down to what is needed to cool the engine is all that you want. Nascar uses tape and only removes as much as needed which can vary from day to day and sometimes minutes as things warm up during the day. The aerodynamics are effected by flow through the car and if you create a wall of air that has to go around your front end the better you are at higher speed. I have often thought about a louvered or slotted grill that can open and close the amount of air flow contolle by a manual cable or by a temp contoller that activated step motor or vacuum cylinder to open and close it from a bellcrank. It not only would be funtional but if done right would look really cool too. I keep thinking about how to use the DCC contoller to do this. Maybe with a little help they can come up with a kit?

Jim Nilsen

Kenova
01-15-2006, 06:29 PM
..........I have often thought about a louvered or slotted grill that can open and close the amount of air flow contolle by a manual cable or by a temp contoller that activated step motor or vacuum cylinder to open and close it from a bellcrank. It not only would be funtional but if done right would look really cool too. I keep thinking about how to use the DCC contoller to do this. Maybe with a little help they can come up with a kit?

Jim Nilsen
Check out some of the big diesel trucks. It's quite common for them to have louvered grills that open and close (needed mostly for colder climates). I'm sure you could find a few ideas there.
Ken

Damn True
01-16-2006, 11:13 AM
Jim,
Have you ommited the assembly that supports the front valance, header panel and the hood release mechanism as well?

If so, what if anything is supporting your valance and header?



Hi Steve, I have mine in the pile of parts that won't be going back on the car. I have my hood going the other way now but it is something that I believe you could live without. If in doubt you could leave the safety latch on since it doesn't weigh that much and is what makes sure the hood stays down if the main latch fails. I too have had a hood fly up on me once and that is why I turned mine around.

I am also a firm believer that air has to get in to get out and restricting the air inlet size down to what is needed to cool the engine is all that you want. Nascar uses tape and only removes as much as needed which can vary from day to day and sometimes minutes as things warm up during the day. The aerodynamics are effected by flow through the car and if you create a wall of air that has to go around your front end the better you are at higher speed. I have often thought about a louvered or slotted grill that can open and close the amount of air flow contolle by a manual cable or by a temp contoller that activated step motor or vacuum cylinder to open and close it from a bellcrank. It not only would be funtional but if done right would look really cool too. I keep thinking about how to use the DCC contoller to do this. Maybe with a little help they can come up with a kit?

Jim Nilsen

Steve1968LS2
01-16-2006, 05:05 PM
Jim,
Have you ommited the assembly that supports the front valance, header panel and the hood release mechanism as well?

If so, what if anything is supporting your valance and header?

Omitting the supports would be bad.. the upper valance needs some sort of support.

I will just remove the latch mechanism, not the plate itself or the downward support. You can carry weight reduction a bit too far :)

Damn True
01-16-2006, 05:15 PM
Well it would'nt be tough to fab up some tube struts to take the place of the header and valance support.

Kinda sounds like Jim ditched the whole shebang. Wondering how he addressed support.

Jim Nilsen
01-17-2006, 12:33 AM
I have ditched the original support but not the need for a support. You are all correct that you need support. I don't have the original radiator support anymore. I will have a sheet that goes from the new radiator support to the header panel that is similar to what Steevo has on his car and what you see on many other cars that are blocking the air from getting past and going to the engine bay. The other new new support will attach to the same points that are on the lower valance and to the mounting point on the upper header and back to the radiator support. I have created something that I believe has as much strucural support for the whole assembly as the original and will have the support to carry the weight of the hood also.. I have kept what I am doing somewhat out of the limelight because I want to be the first to have it. The simplicity of it all and the weight savings of the whole system took me over 500 hrs or twice that of engineering. Take 14 years to build your car and you have that going for you. I never dreamed that someone would pay $800 to over $1000 for a hood hinge setup but Electrolite and the new billet hood hinges have proved that I was wrong about that. If I had known then what I know now I would have started selling them, but maybe now is the time to start. I am getting closer to putting the front clip on and when I do you will all see what I have come up with. You can all get a big tease by going to my website but the details are not really shown well. For those of you that can see what it is I am doing you will understand and for those that can't, you will just have to wait. I enjoy sharing all of the info I can here but since it is taking me soooo long to do my car because of finances like a lot of others here I have held back. I hope you all understand my desire to have the first setup like I am going to have and if you can figure it out before I get it done I will be impressed.

I am not saying that Steve should ditch the whole support brace only part of it. Mainly the pin, the spring , release and the lever which doesn't weigh much but it is what he was inquiring about being needed or not. The plate from the header to the radiator support is all that is needed to tie it all together and could be replaced with an aluminum piece if he wants to fab it up.

Jim Nilsen

Steve1968LS2
01-17-2006, 06:31 AM
Well it would'nt be tough to fab up some tube struts to take the place of the header and valance support.
.

Quit making my project more complicated! lol

Steve1968LS2
01-17-2006, 08:05 AM
I am not saying that Steve should ditch the whole support brace only part of it. Mainly the pin, the spring , release and the lever which doesn't weigh much but it is what he was inquiring about being needed or not. The plate from the header to the radiator support is all that is needed to tie it all together and could be replaced with an aluminum piece if he wants to fab it up.

Jim Nilsen

What about the long down brace that goes from the upper latch assembly to the lower part of the core support and the center of the lower valance. How important is that?

I only have a bit over a month to finish my car so I have to pick my battles in regards to fabbing stuff up..

69Nova
01-17-2006, 09:19 AM
I only have a bit over a month to finish my car so I have to pick my battles in regards to fabbing stuff up..

Why do you have a deadline?

Damn True
01-17-2006, 11:34 AM
Quit making my project more complicated! lol



Trying to get you to do my R&D for me.

Travis B
01-17-2006, 12:04 PM
Why do you have a deadline?


hes a magizine guy he likes the drama :poke:

Jim Nilsen
01-17-2006, 09:30 PM
Sorry I didn't make it more clear. The other new support I was talking about is the one you are talking about. You definately have to have something to tie the 3 parts together or you will more than likely have trouble with the grille possibly cracking somewhere from flopping and vibrating around. The original steel support brace really isn't that heavy. I will be fabing a new one out of aluminum that ties into the aluminum sheet that goes from the new radiator support to the header panel and down to the lower valance. I wish I had a cad drawing program to be able to show you or could sketch it but it really isn't to hard to figure out and can be done with posterboard to make templates and then transfer onto sheet aluminum and cut out with a sabre saw and bandsaw if you choose to change it all. It is much easier to do with something other than the stock radiator support so I can understand your extra difficulty. Always remember that most factory braces and brackets are usually made as light as you can make them to begin with and are usually formed to be stronger than flat stock.

If you really have a deadline to worry about I would just put it together like stock and not worry about it. you will only save about 2lbs max anyway. Leaving the pin and the spring off will save the most weight anyway and acheive somewhat the goal you are trying to go toward.

Keep it simple for now or you will be like me and have it apart longer than it is together ,LOL

Jim Nilsen

Damn True
01-18-2006, 09:40 AM
Jim, I've been pouring over your photos and can't for the life of me figure out what you are doing. I have some ideas in mind for my project, I'd like to bounce a few things off of you. It sounds like we are going down similar roads.

Jim Nilsen
01-18-2006, 09:57 AM
True you have a PM.

OHCbird
01-18-2006, 08:42 PM
Steve- maybe I'm reading this wrong... but are you inferring that the cowl area, or the cowl induction hood makes a good extractor or area for extraction? That counters the original design of the cowl hood-which was to pull high pressure air from the cowl area. You'll find that you get flow into the engine compartment around the cowl area (vice pulling it out).

As an example- look at the typical NASCAR air cleaner housing that is fed from the cowl area. Your best bet is to try to find a negaitive pressure area along the side if it becomes a big concern (which I don't think it will). I would also never want hot engine compartment air (and possible steam / oil) routed over the windshield.

Just a thought...
PS- Sweet ride!

MrQuick
01-18-2006, 10:53 PM
That counters the original design of the cowl hood-which was to pull high pressure air from the cowl area. You'll find that you get flow into the engine compartment around the cowl area (vice pulling it out I agree, you would remove more air from further down the hood. Say L88 style hood. You can do a search Steve, there are bolt on fiberglass louver plates that you can use around the hinge area. Look ok too. Mid 90's jeep used them too.

Steve1968LS2
01-19-2006, 07:23 AM
Steve- maybe I'm reading this wrong... but are you inferring that the cowl area, or the cowl induction hood makes a good extractor or area for extraction? That counters the original design of the cowl hood-which was to pull high pressure air from the cowl area. You'll find that you get flow into the engine compartment around the cowl area (vice pulling it out).

As an example- look at the typical NASCAR air cleaner housing that is fed from the cowl area. Your best bet is to try to find a negaitive pressure area along the side if it becomes a big concern (which I don't think it will). I would also never want hot engine compartment air (and possible steam / oil) routed over the windshield.

Just a thought...
PS- Sweet ride!

That makes sense since that's the air feed for a cowl INDUCTION air system... maybe I was low on coffee that day.. lol

I would love to have something like the Mule has but not sure if I have the coin yet to do it. If it was just a matter of punchin louvers then no problem, but I think there is quite a bit of underhood modification that needs to be done.

Back by the hinges would be better than up near the front (El Mule).. right? I know the ones on the Mule are there as heat extractors for the turbos.

I will check out the hood tomorrow and see what can be done..

I got you on the vent to the windshield, the hot air would help defog the glass.. lol.. the hot oil and "stuff" would be bad though (on many levels)..

Not like I will trying for the 200mph club, but I like working through stuff like this, it's edumakational ;)

Damn True
01-19-2006, 09:14 AM
If you get back by the hinges you will run into the same problem. It's a high pressure area.

What you want, (and I am mulling over different was to do this as well) is to take advantage of a location where the airflow is accelerated, and therefore is at a lower pressure (Bernoullis Principle) than the airflow nearby or adjacent.

Two ways to do this:

a) find a location on the hood where the pressure is lower at speed than beneath the hood and simply provide an exit path. Air will flow from an area of high pressure to low by itself (just like a santa ana wind). As the air flows over the front of the car and across the curvature of the front of the hood it is accelerated relative to the relative airspeed of the car. Therefore the pressure there would be lower than the undehood air pressure. Thus, the extractors on the hood of the mule, the viper or on the C5 or C6 GT1 cars.

You can give this effect a little help as well by creating a bit of a lip on the upstream (toward the front of the car) side of the extractor. This further restricts the flow of air across the hood. Restrict flow > increase flow velocity > decrease relative pressure > increase pressure delta > increase air extraction effect.



https://static1.pt-content.com/images/noimg.gif

https://static1.pt-content.com/images/pt/2006/01/48130hood2-1.jpg

https://static1.pt-content.com/images/noimg.gif

Jim Nilsen
01-19-2006, 10:09 AM
Another way to address the problem of air in the engine bay is to not let it get in at all. With the right amount of sealing at the radiator support and only letting air get through the radiator you could actually create a low pessure area in the egine bay and then the air would come into the engine bay through the cowl or other vents instead of escaping.

The right air dam and splitter at the front of the car can help in creating the low pressure area in the engine bay. There are always 2 ways to look at air flow and the biggest problem we all have is that our cars are not always moving like race cars are so how we have to go about cooling is completely a different animal to tame.

Overheating problems are usually and hopefully solved with a large enough radiator and proper airflow through the radiator as far as everything else you can use the air that flows through a car as a way to create downforce or get lift. We all know that we don't want lift of anything especially the hood and we don't have the luxury of putting venturi's in our cars like an indy car or F1 can to direct it for our advantage.

I always like thinking of it as it has to get in to get out and if you get it to go around the car car instead of through it you will create less drag. Enough to cool the engine and other components is all the air you want to get in from what I have learned over the years which goes right back to the Nascar tape over the grill or the sealed off radiator support to the rest of the engine bay as I described above.

The subject has even the best of experts always debating over what is best and it changes with each application and car.Keeping it simple is usually the best way for our applications.Less is usually more.

Jim Nilsen

Damn True
01-24-2006, 09:38 AM
These aren't a bad looking arrangement for heat extraction. I think I'd prefer to see a bit of raised surface (a small lip) at the leading edge of the extractor though.




https://static1.pt-content.com/images/noimg.gif

Damn True
01-26-2006, 04:14 PM
Im pretty sure you could order a set of these w/o the holes on the perimiter. They'd look terrible bolted on, but you could easilly weld them in flush.

https://static1.pt-content.com/images/noimg.gif

SoCal69
01-26-2006, 06:51 PM
Steve- Another spot that allows air into the engine compartment is around your headlights, if you're using your stock core support. Air conditioned cars have filler panels that block that area from the core support to the inside of the fenders. I have a big block stuffed under the hood and it always overheated when idling. I found that the hot air from the backside of the radiator was circling around and coming back through the radiator because that was the path of least resistance. This superheated air actually melted my side lights. I fabbed my own panels and solved that problem. The A/C cars also had a pan underneath that forced the air past the crossmember before exiting under the car.

zbugger
01-26-2006, 10:48 PM
Im pretty sure you could order a set of these w/o the holes on the perimiter. They'd look terrible bolted on, but you could easilly weld them in flush.

https://static1.pt-content.com/images/noimg.gif
But it would look cool riveted in. :smoke:

Damn True
01-27-2006, 10:36 AM
Perhaps on a flat black hood?

Actually I spoke to the guys at Evolution yesterday about perhaps getting their hood made for an actual 1st gen. (The one in the photo above only fits their custom carbon fiber body) Though in fiberglass, or glass with a cosmetic CF outer layer. We also discussed the possibility of them making just the heat extractor device in CF to be installed in a standard glass or steel OE type hood.

Anyone interested in such a thing?

1Bad68camaro
01-30-2006, 12:06 AM
I would. Where did you find the ones in the pic you put up?

Damn True
01-30-2006, 10:13 AM
Actually, in talking to a buddy who works at boeing...who happens to have a airflow modeling program....(neato!) those stamped steel louvers do not have enough open area to draw an appreciable amount of air from beneath the hood. According to him, there would be flow, but not enough to make any form of noticeable difference.

An arangement similar to that on the Evolution car above would be more effective, especially if combined with a lip at the leading edge.

We are looking at a couple of different configurations using side vents from a Y2k mustang amongst other things.


In regard to the evolution hood or extractors, I'd like to find out how much interest there might be in such a thing. Perhaps I'll start another thread surrounding that subject.