Is there any kind of consensus as to how far I should be mounting this in the hood? I can only go 13" back from the front of the hood, as shown here. Any further back hits the valve cover. Is this far enough back to help with heat extraction?

 

If you ever plan on 1.8 swapping, put it far enough forward for that. Otherwise, as far back as you can go. There's a picture floating around of pressure on the hood at speed - pick the spots that have the lowest pressure - IIRC this is basically as far back as you can go with a 1.8 valve cover.

 

Done, I'll put it almost as far back as possible, as a 1.8 swap in the future isn't out of the question.

 

Do a search, noob!

Actually this was covered a while back. I don't have time to find the thread, but the consensus was that you can't go any further back than the hood bulge without a lot of farting around to get it to sit flush.

Since I got mine that same time you got yours, I was wondering who would be first to take the plunge. Personally, I plan on moving it forward from where you have it by about 1.5-2 inches. Just so the back edge is at the front of the hood bulge.

 

That's a good point, although I'd rather have function over form. Once I find my jig saw it's on.

So you bought the dudes other scoop?

 

Yeah, I got it. I haven't found the thread, but I will, and post a link.

I think you get lower pressure in the front, so it works either way. Quite frankly, I'm not looking for absolute perfection as far as efficiency, and making it fit well is important so it doesn't look cobbled. Mine has some tabs broken off, so I'm not quite sure how to fasten it down.

 

I'm not sure I trust the tabs at speed, I may end up bolting it on. I haven't looked too long at the bottom.

 

what scoop is that? looks like a mini's scoop

 

hence the thread title.

 

you changed it to make me look dumb. I don't miss anything. Leave me alone.

 

thread title has not changed.

 

Further forward will extract better. Lowest pressure area on the exterior of the hood is near the leading edge. at some point though I think when you get too far forward it wont make the corner well as it exits the back side of the radiator but it has to get pretty extreme for that to be the case like with the opening forward of the radiator. In reality you can sort of think of the under hood air flow to behave more like a pressurized box than having much aerodynamic flow characteristics to it. Put the exit where the pressure is lowest on the outside of it and it will flow more out. The opening placed just an inch or two behind the fans is good.

Bob

 

Can't say that again. I helped poor Pusha out a bit.

Ok, that's perfect, as it'll let me avoid the hood hump. I believe having the forward edge 13" from the front of the hood is roughly 3-4" behind the stock fan shrouds, I'll probably mount it towards the short side of that variable.

 

Where you have it taped on is pretty much exactly where I molded mine in. It is about 1/2" from the valve cover when closed on a 1.8L engine.

 

These diagrams I had previously saved might help you out with placement. IIRC V8Roadsters did the pressure testing. That pressure diagram, I don't recall where I found that originally so unfortunately cannot provide appropriate credt to the source.

 

In that last image, cooler colors are high pressure and warmer are low? Just want to make sure I'm reading that correctly.

 

red is low pressure, blue is high. iirc

 

...and it moves a ton of air in that location. I can't really use the blower on cool days because the air is so hot coming out of the hood, but when I tape it up its cool again.

Do yourself a favor and rather than fab-up that Mini scoop, riven on a carbontrix vent.

 

Looks like a plot of total pressure to me. So it is a bit more confusing to look at. Total pressure is a combined is a combination of static pressure and velocity, ½ rho V^2. Like you would measure in a free stream with a petot tube facing the flow direction. In the picture Red is a combination of high velocity and low static pressure and blue is low velocity high pressure. It is deceiving because behind the wind shield is not really high static pressure but it is much lower velocity yielding the blue color.

The darker red area on the hood is where you want the vent it is both high velocity and low pressure. It will suck air out of the engine compartment and reduce front end lift on the car.

Bob

 

Cut and placed, still need to bolt it in. God I hate aluminum dust.

During cutting:


Shitty outside photos trying to capture location:



Shitty inside photos trying to capture location:


Say hi to Jack


Underside shot showing a lot of the layers if you look closely that I had to cut through, it was a major pain to get it as clean as I did. Luckily all mistakes are hidden by the scoop itself.



I have about 6.5" from the leading lower edge of the scoop to the back of the radiator. With a small trim of the back edge I could get another .5". Don't know if I care that much. Just need to trim the front bracket off the scoop which I was using to hold it in place in the pictures, and I can drill some holes for bolts. Woot me.