BUILD-OFF CHALLENGE: Tygaboy's '75 LS3, It seemed a good idea at the time... Options

[tygaboy]

Clearly I am out of my depth. I look at the strings and see the car is moving and they are just blowing with the wind hitting them. How does that show air being drawn from the radiator out of the vents? If you tied string to the same location on the driver's side, would the string not blow around too?

How about a fogger machine you sit in front of the car and turn on to see if the smoke comes out the vents?

OK, never mind, my mom always told me, "Better to remain silent and be thought a fool than to open your mouth and remove all doubt". I never learn. (IMG:style_emoticons/default/beerchug.gif)

@Cairo94507 Michael - At some point, I don't really care WHAT'S happening, so long as the cooling system functions well. The litmus test for me is that the car doesn't overheat - and so far, it doesn't. And, any air that's coming through the openings in the nose has nowhere else to go but out these vents.
If there were insufficient airflow while driving, the fans would come on. They don't - until the car sits for a bit. Even then, as demo'd in the earlier video, they cycle off pretty quickly.

These vents were always a styling "form over function" effort and an attempt to avoid cutting the inner fenders. Worst case, if they didn't "work", I could always open up the inner fenders a little at a time until, in combo, things did work. At this point, these sure look like a success.

[914forme]

Yes you are seeing the flow, the one real way to know is with smoke generator in front of the RAD and drive, and see where it leaks out. My guess is it will come out the vents, it almost has too, some might seep out around your seals, and if your separation seal is bad or not in, might come into your cowl area and seep out into the interior.

Other way would be with infrared video look at the temp difference in the airflow, or temp sensors placed all over the car.

A set of vortex generators would work also. Pull the airflow down over the vents.

You are fine if it is working. And if you run into issues, well you can always add ducting to help the airflow go where you need it.

[914forme]

If it becomes and issue you add ducting.

If it really becomes and issue, add a small snowmobile engine and a cooling fan off an M1 Abrams tank, its magnesium so it weights nothing. You will be cleaning the street as you drive. And you will see the trash fly up in front of you so you know it is working as it should.

[andys]

Chris,
What are the specs on your radiator fans (Dia. CFM, amps)? Apologies in advance if you posted them before.
Thanks,
Andys

[Rand]

I have to say, this is a pretty momentous occasion for me. Tony @RetroRacer

Yeah, reverend troublewho is absent? (IMG:style_emoticons/default/poke.gif)

[tygaboy]

Chris,
What are the specs on your radiator fans (Dia. CFM, amps)? Apologies in advance if you posted them before.
Thanks,
Andys

@andys - I don't know off the top of my head. I have the Renegade set up that I got from them like three/four years back. I think they're like 14". Here's a pic - it's from before everything was done but this it the set up. And no, that's not the shroud top I have on the car now. I made one with no cut outs for "get it running/driving".

[Retroracer]

I have to say, this is a pretty momentous occasion for me. Tony @RetroRacer drew up what I think is the best looking H2O cooled 914 vent set up I've ever seen and today, I drove my car with real live versions of his design in place and functioning.
I say "his design" and by that I mean, the closest I could get with my current skill set. I hope I did you proud, my friend.

Tony,
THANK YOU so much for taking time to do that drawing as well as all that time you spent talking with me about all the details. You have added what I think is the key design element in my build.
I owe you BIG TIME.
Thanks again!

Man, I LOVE this forum.

Chris - you're very welcome and am just a bit amazed that you followed that scribbled idea all the way down the rabbit hole! As others have stated, this is kind of a confilicted thread: I want to see it continuing with regular and more exciting installments, with photos and monster TIG work, metal shaped, etc; but at the same time I want you to finish the build so I can grab a ride in it!

- Tony

PS. Rear trunk / engine lid design next..... (IMG:style_emoticons/default/evilgrin.gif)

[Cracker]

I liked your idea a few months ago of altering the water pump speed based upon the coolant temperature...scaling as needed in either direction. That had some real teeth but of course, you could not see that - it likely would have just worked.

Not feeling this design but if you are happy with it then that is all that matters. From a functional viewpoint, I don't see anyway that is an improvement for several reasons, over many tried and true venting designs. If you just want to vent your hood differently, so be it. Would it be better on a racetrack at the limit? I think not but also could certainly be wrong...

BTW: Your car sounds great during the front mounted test - great job!

[Krieger]

I love the yarn test! It is such a very helpful tool for us home builders. Idk if it was just the stiffness of the "yarn" or that there was not a lot of them in the front of the vent, but the airflow didn't seem to be as robust in front. This may be totally irrelevant if your car stays cool. Yesterday's ambient temperature was 60°

[cassmcentee]

Love the Youtube "build update" snippets Chris
Once warmed up, your engine sounds like a MONSTER
Cheers

[BuddyV]

Yarn or no Yarn.... Chris's car can eat your car.

(IMG:style_emoticons/default/beerchug.gif)

[Andyrew]

Great test!!!!

Here is what I see. The fans come on and show that at 100% airflow through the radiator X amount of movement is shown in the strings. This is at sufficient air speed relative to the radiator to cool it in traffic according to Renegade.

Then, at speeds of what appear to be ~50mph that flow is drastically improved.



Chris here is what I suggest for the next test.

1. Buy an airflow meter.
https://www.amazon.com/Qotone-Anemometer-Wi...0NsaWNrPXRydWU=

2. Test the system with the radiator fans on.

3. Test the system at 50mph in free air flow

4. Test the system at 50mph against the vent. (Gopro and duct tape (IMG:style_emoticons/default/smile.gif) )


Compare data and draw analysis (IMG:style_emoticons/default/smile.gif)

I say air going through one vent at 25% free air flow would be significant enough to not require any additional venting.


I would be curious how speed reflects the vent efficiency/ your total airflow efficiency.

Also curious how the vent being open vs having louvers affects airflow.

One could reposition the meter and adjust all the vanes of the louver for optimum efficiency at a specific speed (IMG:style_emoticons/default/smile.gif)

[tygaboy]

First attempt at screens only with no walls, just to see what it might look. It's a no-go IMO because, as expected, the corners where the mesh has to meet up at the different angles will never look right. And I'm not a fan of how it looks where the screen meets the hood skin.

So it's back to fabbing some AL walls. In playing around with how to attach the walls, I realized I have to make a couple revisions to the design. It's always something.

[tygaboy]

If you squint really hard, and imagine it with the lights installed, painted, with the vents finished and everything else in place, all tuned and running well... (IMG:style_emoticons/default/happy11.gif)

Hey, it's what keeps me going.

[Cairo94507]

I think you are just about there. Happy Thanksgiving Chris. (IMG:style_emoticons/default/beerchug.gif)

[andys]

Clearly I am out of my depth. I look at the strings and see the car is moving and they are just blowing with the wind hitting them. How does that show air being drawn from the radiator out of the vents? If you tied string to the same location on the driver's side, would the string not blow around too?

How about a fogger machine you sit in front of the car and turn on to see if the smoke comes out the vents?

OK, never mind, my mom always told me, "Better to remain silent and be thought a fool than to open your mouth and remove all doubt". I never learn. (IMG:style_emoticons/default/beerchug.gif)

@Cairo94507 Michael - At some point, I don't really care WHAT'S happening, so long as the cooling system functions well. The litmus test for me is that the car doesn't overheat - and so far, it doesn't. And, any air that's coming through the openings in the nose has nowhere else to go but out these vents.
If there were insufficient airflow while driving, the fans would come on. They don't - until the car sits for a bit. Even then, as demo'd in the earlier video, they cycle off pretty quickly.

These vents were always a styling "form over function" effort and an attempt to avoid cutting the inner fenders. Worst case, if they didn't "work", I could always open up the inner fenders a little at a time until, in combo, things did work. At this point, these sure look like a success.

Chris,

Well said. Bottom line; Does it work, and do you like it?

It's times like these that I miss my former stylist/designer neighbor, Mike Williams, who could rattle-off the appropriate aerodynamics and make it look great as well. He designed bodywork for the Can Am Championship winning Shakee Can Am racer, various Indy and exotic car projects, worked at Pontiac and Jeep, and his own design studio. He truly had a gift. I was fortunate enough to work on a few projects with him.

Andys

[tygaboy]

Earlier I'd mentioned I wanted to try a "straight across" version. Here's the first attempt at the design. I need to update a couple minor things but my first impression is that I kinda like it.

What's nice about this design is that, compared to the previous version, it doesn't require dissection of near as much of the support structure - so much simpler mods to the hood.

And I think I can get away with adding a single strake to better stabilize the vents.

[tygaboy]

couple more

[Rand]

I almost commented earlier but didn't figure my input mattered. However, since you brought it up....

Notice the curve of the front. And the curve at the top. (of the hood)
I think the curve in the middle should be a variance on that curve. The hood has curves at top and bottom, so I think you should average in between. The design is already there for you to work with!

[Rand]

Visualize the curves and match.
Doesn't have to be a curve as short as they are, but match the angle.