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Thu Feb 19, 2015 6:47 am

Does anyone know if the engine fan could draw enough air to cool the engine if there were only one set of intake louvers?

This would leave engine cooling louvers on one side of the car only and removing both the louvers and ducting on the other side.

Thanks

Thu Feb 19, 2015 7:26 am

No, I wouldn't chance burning up my engine for style.

Thu Feb 19, 2015 7:34 am

If you plan to try it, do your testing on a really cheap motor you don't care about.

I would highly doubt that the early "shark gill-style" louvers would flow enough. With my 2056cc, I would notice a spike in head temps at around 60mph. As soon as I added the NACA ducts on either side and ducted them to the cooling air inlet, my temp spike not only went away, but the faster I go, my head temps now drop a bit (approx 50-75 degrees).

Through my anecdotal testing, I have come to the conclusion that the gill-style vents, while IMHO are definitely better looking, they appear to be effective to around 50-55mph and then begin to stop flowing air effectively.

I have never tried the late style vents on my car even though I have a set of fenders to cut them out of. I just don't think they look as good. But I can see the advantage of having the vents reversed in the air flow to pull air in. VW obviously thought it was a good idea and changed it in '70 on all SB & FB cars and apparently offered a retro modification kit offered at dealers (?) for earlier cars. . .

FWIW. . . 8)

Thu Feb 19, 2015 8:35 am

Mike Fisher wrote: No, I wouldn't chance burning up my engine for style.

I have to agree with Mike on this one. I only say that, as pulling air from only 1 side limits how much air the engine can draw (why it has louvers on BOTH sides).

Now, IF you were building a "trailer queen" that won't be driven (except on and off the trailer), then go a head and do it. In this case, you could fill both sides, and remove the boot, as the engine won't be running very long anyway. :roll:

Thu Feb 19, 2015 11:09 am

Why?
Just wondering what you're attempting, since it can't be a "style" thing.

Fri Feb 20, 2015 6:12 am

You are correct, its not the style thing. I am considering several major modifications some of which would require significant air for cooling, separate from the air needed to cool the engine.

Trying to modify the car in a respectful manner, with a neat install; makes the customary approach of adding a heat sink components in the spare tire well, running plumbing under the floor pan and cutting big holes in the valance under the front bumper not ideal for me.

I had hoped that the large volume of space in the interior of the ducting would make an ideal, neat, installation location. Also, that the original louvers and ducting solved the problem of a supplemental air supply without scoops and things hanging off the car in strange places. Unfortunately I have been speaking with some engineers on this approach and, while cooling the engine may be possible with one duct, the manner in which our fans are driven complicates this, and the horse power draw imposed by the increased load on the fans ultimately makes this approach impractical.

Thanks to everyone for their replies.

Sat Feb 21, 2015 3:17 am

any thoughts on notchback style vents? they are just open slots with very thin "webbing" in between them, unlike the louver style of the fasty and square.

I have tried full revs and putting paper over the corner opening at the end of the boot lid corners when the boot is open to see if that extra vent when open want to suck air, basically gauging if the normal vents are a restriction.

doesn't seem to be at all. but at high speed Im not sure as I haven't tested that.

Sat Feb 21, 2015 7:24 am

vlad01 wrote: any thoughts on notchback style vents? they are just open slots with very thin "webbing" in between them, unlike the louver style of the fasty and square.

I have tried full revs and putting paper over the corner opening at the end of the boot lid corners when the boot is open to see if that extra vent when open want to suck air, basically gauging if the normal vents are a restriction.

doesn't seem to be at all. but at high speed Im not sure as I haven't tested that.

I have not tested the Notch vents either, but I do hope to in the future on my '65S, but not for engine cooling air flow. . . It's all speculation at this point, but I doubt that the Notch vents have any of the issues of the early/late engine vents in the SB/FB cars due to their proximity to air flow and how they are positioned in relation to that flow. Much better positioning on those vents similar to the fresh air vents in the front of the windshield only a lot bigger with air flowing 90 degrees to the surface (more of a ram effect). Conversely the FB/SB vents lay parallel to the air flow with the shape of the vent openings being critical in how much air is pulled/drawn in. That is one reason these type have to be much bigger (like the old split bus vents).

Again, all that is speculation on my part based solely on logic and anecdotal experience. I failed math in HS and my physics knowledge is limited to "I know that stuff hits the ground when dropped". :wink: :lol:

Sat Feb 21, 2015 10:06 am

vlad01 wrote: any thoughts on notchback style vents? they are just open slots with very thin "webbing" in between them, unlike the louver style of the fasty and square.

I have tried full revs and putting paper over the corner opening at the end of the boot lid corners when the boot is open to see if that extra vent when open want to suck air, basically gauging if the normal vents are a restriction.

doesn't seem to be at all. but at high speed Im not sure as I haven't tested that.

Having had two Notchbacks (both early and late), I can tell you that the ducting is very long on both sides. While you see the louver openings on both sides under the rear window, there's a bridge of ductwork under that entire area. It's also not very "deep", as you don't want to loose any trunk space. Add in that, that area is a "low pressure" air area. Also, the side ducting is kept semi thin (compared to a Square or Fastback), so this can cause air to "pack" into the duct. And when you add in that the later Notchbacks didn't get the "direction divider" in front of the cooling bellows, can cause both sides to to be inbalanced from the air "packing" the ductwork. Look at a Square or Fastback (Monte's or Clatter's), and you'll see how short the run actually is. The Notch draws it's air in from below/behind the rear window, then travels alongside the engine bay, then dumps in to the rear apron, before finally entering the engine. Lots of 90 degree bends. :shock: That's a long way for the air to travel. :wink:

Whether this can cause a problem for a large engine, possibly. The ducting and openings were designed for a 1500cc engine afterall.

Just my take on it, and I'm in no way an aero engineer. :lol:

Sat Feb 21, 2015 9:05 pm

Thats interesting with late notch and the divider not being there. They must of done that for a reason. Possibly because the notch intake plenum is already balanced at the bridge under the screen.