The vent outline I have so far runs all the way across the centre depression on our hoods. A ridge just looked 'tacked on' no matter how I did it.

And let's not forget - air doesn't just flow up and over the sloped hoods of our cars. Air strikes the header panel and is kicked up and over the hood, sort of like a bug deflector on a pickup truck, and the airstream isn't pushed down again until just before the windshield. This results in a pocket of negative pressure along the latter half of the hood that actually pushes up and forward. Just watch the trailing edge of your hood sometime - you'll notice it tries to lift at speed. On second thought don't - keep your eyes on the road

It is this exact negative pressure that I'm exploiting to draw air up and out of the engine bay, venting rad heat to the atmosphere instead of trapping it in with the engine.

Adding a ridge right before the vent would have little to no aerodynamic effect on air flowing over the vents, since it does not do so. Those ridges are added on other cars to kick up the air and create the kind of negative pressure our cars inherently have.

 

How about a Photoshop pic or sketch scan...

It seems that no one knows EXACTLY what your suggesting.

Am I wrong?

 

yeh, I would like to see some sketches

 

here's a quick photoshop of the A type (in bodycolour, not CF)

 

I like it. Looks real clean and subtle.

 

Cool pic - thanks! I really like the concept. The hood is very classy, yet aggressive - without looking ricer.

The only suggestions I would make (not that you're asking)... You might see what it looks like with the edges of the vent a little more curved at the edges - blending into the inner lines of the hood. It would create a little softer, sexier look vs. the Transformer look. It might also work well with some of the other rounded edges on the 1st gen... What does it look like if you bring up and round the center of the vent to meet the center line, essentially creating a dual vent...

Also, at first glance, it seems the vent should be further down the nose...

Just observations...

Thanks again for making the pic, I hope you can actually produce a hood to sell. The more aftermarket parts, the merrier ...

 

Looks good! the vent has to be that far back, cause the radiator sits back far

 

Or can the vent be made less shallow... ?

 

Yeah, the vent should start closer to the front.

 

then this functional VENT becomes decoration, a place for leaves to collect. a wrench holder.......

look at an open hood and where stuff is

 

That's right. I keep thinking the radiator was closer to the front.

 

also shallow is a good thing, as there might be clearance issues.



My Mazdatrix bars sits 2" further to the front than the Cusco pictured here........ hmm.....

 

The vent must be that far back - or it's not a vent. The idea is to pull hot air from behind the rad, not cold air from in front of it.

The vent is made shallow because there's not a lot of open space for the vent to dip into. No point making a hood you can't close!

 

Maybe a tilt forward kit for the radiator like the 2nd gen style...... plenty of room for a vent then.

 

I guess therein lies the rub...

Personally, I could care less about functional - in fact, the hood could have a ridge vs. an actual vent - and with a pleasing design, be just fine by me.

But... maybe the answer is somewhere in between.

Smaller opening, further down the hood. With the curvature of the hood, a vent wouldn't have to be that open to be effective...

 

I'm not sure how you'd pull cold air from the front of the radiator, it's capped off.

But that's not really the point. Speaking as a consumer only three things matter to me: Cost, looks, function - and not necessarily in that order.

Since the looks are being dictated by function: What do I really gain by losing the hot air from behind the radiator? It's done cooling the water, and the engine is certainly hotter than the air. Assuming a have a cold air intake, then what have I lost. And dumb me, I figure most of the hot air is going out the bottom anyway.

Which brings me back to looks...

Mind you, these are just Devil's advocate opinions...

 

"Or can the vent be made less shallow... ?"

RXTbone

I kind of agree, only a little bit more. Why mess with the classic lines on the front of a 7?

http://www.pixfiles.net/images/1379035031.jpg

http://images.cardomain.com/member_i.../479957_15.jpg

Ray

 

is anyone elts having trouble seeing mantis's photoshop pic?

 

never mind, it was me

 

making a vent deeper (less shallow) would change the lines even more, so I'm not sure what your point is.

Guys, at the risk of getting snappy this is starting to get frustrating.

I can't make several different designs to please everyone - each shape costs thousands in design, fabrication, mold construction, labour, and materials.

I can't make the vents deeper or you'd have to modify your engine bay just to make the hood fit.

I can't move the vents farther forward or there's nothing to vent.

The point of vents are not to cool the air even more after the radiator but to prevent the hot air from swirling around the engine by extracting it out the top, making room for cool air to come in through the bottom.

 

manntis, while I will probably never even see that hood in the real world (hey I'm honest) I for one appreciate the hard work and effort you put into every one of these peices for our little pieces of history (in a good way) these classics are made all the beter by enthusiasts like you keep up the good work

 

A

 

Guys, understand this : he's designed it for a 1st gen rx7. not a 2ed or 3rd gen, or a tercel even. not to confuse looks with function. not everything that functions, looks good. the vents HAVE to be a certain place on (in) the hood to function it's not going to move.
and from what i gather he is considering different strut bar mfg's for clearance. the vents, themselves are small
but large enough to function. it's all about the hood. in the following flavors,,,CF, FG, the vents are thrown in,
because,,why not ?. Remember the question ?? A, B, or C, I would warn you manntis to not tie up major funds, unless you know of a market where the product(s) move themselves,,,,you know ?

 

meh, if I make my money back and you guys get slick vented hoods, you'll brag aboot them at rotary gatherings and more people will stop by rotorhead.ca

I want one for myself, for sure.

 

Hey, my bad. I'm not trying to instigate trouble, I just thought the design was open for discussion, and frankly, it's not exactly what I would do. Just like anything, there will be several differing opinions on what looks good, what works well, or both - and I haven't went through the hard work, nor do I have the know-how to build a custom hood. I just have an opinion (which is worth my original 2 cents )

Though potential customers have many needs and opinions, ultimately the fabricator has to make the decision as to what suits his market's needs the best.

Manntis, just take it as constructive criticism. It's a good thing. There's no right or wrong - just opinions. As I stated earlier, I think it's great when anyone goes to the trouble to make a hood, strut tower brace, gauge pod, whatever.... There needs to be items out there for the rest of us to aspire to purchase...

And by the number of comments - at the very least, there seems to be a healthy appetite for a new custom hood! And I sincerely wish you luck with it...