Diffuser and splitter build pics

[dave6666]

I want to know what you do in your spare time....other than drink beer and screwin....this stuff looks like work to me and I bow to the professional!

Lazy sunzabeaches need not apply at Dave-O's.

Yeah, it is work. But I quite often find I get exactly what I want when I build exactly what I want!

I couldn't do it without the feedback and zillions of other posts/pics I looked at before starting though, so once again hat's off to all the Viper Owners on Planet Earth!!!

Time to go saw the splitter out...

 

[dave6666]

1-1/2 hours of cutting and finishing, I now have a splitter.

Kinda looks like one of those things that Wesley Snipes was throwing at the bad guys in Blade doesn't it? Super sized version that is...

A technical note... I went ahead and weighed it as it sits below. Still have some more holes to drill and edges to radius with the router, but it weighs 18.4 pounds as is. I predict 18.0 or so when done.

That weight BTW is near exactly my prediction with the 1/2" thick FRP sheet using the CAD mock up I had posted. So if you are contemplating something similar use the square inches I had calculated and figure the weight of your part.

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Nothing fancy about the arsenal it took to make that piece.

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Back on the fascia.

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I wonder if NASA uses templates like these?

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Moving on to how this is going to be anchored/mounted to the fascia.

It is obvious at this point I am integrating this with the Roe duct opening etc. Anything I am doing along that line could be done without have the Roe duct, but I'm a believer in it.

This piece here...

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Which goes up in the front like this...

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Has been reinforced with a 1" wide x 1/8" thick aluminum strip. As the splitter will mount from underneath with flat head screws, I'm using rivet nuts on the inside of the fascia, which also hold the strip to the Roe sheet metal.

The funny shaped pieces on each end of that big piece - seen on the pics above - are where I tied it into the lower frontal opening. Those are not factory Roe.

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On the fascia with a couple screws installed.

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There's going to be a lot more than that holding it together. BRB...

 

[Fatboy 18]

Fantastic thred Dave

 

[Bobpantax]

Looks great Dave. As usual, extraordinary craftmanship. Question. When I used the Roe air duct on my supercharged Gen II, in addition to the cooling effect, it kept the front end down at speeds above 115 MPH. Before that, the front end lifted too much at 115 MPH and above and there was significant oversteer. Since you are puting on a front splitter, which will, I assume, create significant down force, how will the Roe duct affect this? Since you are one of the most thorough people I have ever seen post anywhere, I assume you thought of this and did some figuring. If not, what is your guess?

 

[Sellshomesdrivesviper]

Nice job again Dave, and please don't forget to put D-O-D-G-E on it, you know how we like BIG decals.

 

[dave6666]

Looks great Dave. As usual, extraordinary craftmanship. Question. When I used the Roe air duct on my supercharged Gen II, in addition to the cooling effect, it kept the front end down at speeds above 115 MPH. Before that, the front end lifted too much at 115 MPH and above and there was significant oversteer. Since you are puting on a front splitter, which will, I assume, create significant down force, how will the Roe duct affect this? Since you are one of the most thorough people I have ever seen post anywhere, I assume you thought of this and did some figuring. If not, what is your guess?

RTcubedTed brought up the same point about that Bob. And to answer your question, yes I have thought about it, and yes it is by logic my answer and not so much by research. I would love to have a wind tunnel or some CFD software but... um, I do not.

To start with, I cannot explain the design criteria/phenomena of the unmodified fascia that causes the lift. Sean Roe researched it using techniques and methods that I will not question. I did have him personally via a phone conversation give me the whole story on that for what it is worth.

So the air that builds up under the front of the car now has a place to go with the Roe duct mod, like out the hood vents or maybe it twirls and tumbles it's way around the engine and driveline tunnel until it exits the car underneath somehow somewhere. If that in effect moved the lift elsewhere on the chassis it appeared to be the lesser evil.

A splitter in simple design terms will increase the pressure both above and below it. Above it = downforce. Below it = lift. Now if you take a car that has been designed to generate negative pressure underneath on the front - that vacuum if you will - then adding pressure to that simply lowers the vacuum. Which of course less downforce could also be called lift.

What if the car already had no frontal vacuum underneath as Sean researched it to be? And what if a splitter raises the pressure even more?

Hmm...

I'd say the hole underneath there is a good idea then.

The research that I have done on this topic also gets into the decrease in cooling air that front engine cars might experience with the addition of a splitter. Seems to me that we've got a basic reduction at that point of air going through the car. That is a very complicated topic and just like the rest of this, there will be no quantifying before and after with measurements, at least by me.

Another aspect of the splitter design I am using - the ACR copycat model - is that in the front of the car where the air must decide to go up or down or whatever, there really isn't much of a splitter there. Just an inch. Move aside of the front and we have 3" of splitter. So how will that design affect air at the front of the car? My guess is minimal.

Finally, as I have mentioned this book before and just now am stating this "research" I have done, I read this book cover to cover. From Amazon for like $25 or so. Very technical it was.

So I'm a full click above dummy. Kinda like staying at a Holiday Inn Express I guess.

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[doctorbob]

See.....I was right. This is work. I bought an ACR and said to heck with it. I am going to keep it stock though, no white hood vents for me

 

[Tom F&L GoR]

Dave, as you know I am a tried and true dirty fingernail type. I have a suggestion to evaluate the airflow through the Roe duct, which you can ignore or improve as you see fit.

Get some of your sheep friends to donate some wool. Spin a few threads about a foot long and tape one end to the leading edge of your splitter. Let the other end dangle on the ground. Go out and drive the car 100 MPH and return. If the threads are still hanging down on the ground, then maybe there isn't much air flowing up into the Roe holes. If the threads are through the hole and stuck on the radiator, then there is. I'm sure you see the principles involved and will fine tune this...

Please report baa-ack.

 

[All Blue ACR]

Hey, a new place to set your beer(s) while oyou work on your car!!

 

[dave6666]

Dave, as you know I am a tried and true dirty fingernail type. I have a suggestion to evaluate the airflow through the Roe duct, which you can ignore or improve as you see fit.

Get some of your sheep friends to donate some wool. Spin a few threads about a foot long and tape one end to the leading edge of your splitter. Let the other end dangle on the ground. Go out and drive the car 100 MPH and return. If the threads are still hanging down on the ground, then maybe there isn't much air flowing up into the Roe holes. If the threads are through the hole and stuck on the radiator, then there is. I'm sure you see the principles involved and will fine tune this...

Please report baa-ack.

I'm already planning the outing now. I'll borrow a line from the Blue's Brothers movie:

I'm on a mission from Tom officer...

And yeah, my front plate musta got sucked up in there where that string goes.

 

[Bobpantax]

RTcubedTed brought up the same point about that Bob. And to answer your question, yes I have thought about it, and yes it is by logic my answer and not so much by research. I would love to have a wind tunnel or some CFD software but... um, I do not.

To start with, I cannot explain the design criteria/phenomena of the unmodified fascia that causes the lift. Sean Roe researched it using techniques and methods that I will not question. I did have him personally via a phone conversation give me the whole story on that for what it is worth.

So the air that builds up under the front of the car now has a place to go with the Roe duct mod, like out the hood vents or maybe it twirls and tumbles it's way around the engine and driveline tunnel until it exits the car underneath somehow somewhere. If that in effect moved the lift elsewhere on the chassis it appeared to be the lesser evil.

A splitter in simple design terms will increase the pressure both above and below it. Above it = downforce. Below it = lift. Now if you take a car that has been designed to generate negative pressure underneath on the front - that vacuum if you will - then adding pressure to that simply lowers the vacuum. Which of course less downforce could also be called lift.

What if the car already had no frontal vacuum underneath as Sean researched it to be? And what if a splitter raises the pressure even more?

Hmm...

I'd say the hole underneath there is a good idea then.

The research that I have done on this topic also gets into the decrease in cooling air that front engine cars might experience with the addition of a splitter. Seems to me that we've got a basic reduction at that point of air going through the car. That is a very complicated topic and just like the rest of this, there will be no quantifying before and after with measurements, at least by me.

Another aspect of the splitter design I am using - the ACR copycat model - is that in the front of the car where the air must decide to go up or down or whatever, there really isn't much of a splitter there. Just an inch. Move aside of the front and we have 3" of splitter. So how will that design affect air at the front of the car? My guess is minimal.

Finally, as I have mentioned this book before and just now am stating this "research" I have done, I read this book cover to cover. From Amazon for like $25 or so. Very technical it was.

So I'm a full click above dummy. Kinda like staying at a Holiday Inn Express I guess.

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As always - interesting and informative with a touch of humor. Thanks. In case it was not clear from my initial post, I thought the Roe duct did a great job. It was an inexpensive and very effective mod for my former Gen II. In my case, it, along with the supercharger, were installed at Sean's by Sean, Dave and the Seanettes. But that was many moons ago.

 

[dave6666]

Just when I thought that aluminum piece up in front of the fascia was all done and time to move on, a couple of my project design specs sent me back to working on it. Those specs are...

-> The fascia and splitter will be independent structures. Easy to say on the splitter itself, but when it is removed from the car I want all of that aluminum inside the fascia to stay put even at speed.

-> I want all of the layers (splitter-fascia-aluminum) to be snug against each other. No rivet heads etc being smashed by a mating surface.

I am using all of the original pop rivet holes for the new splitter mounting screws, so I decided to drill some more holes in-between the old holes. I'll re-rivet the aluminum duct to the fascia with these new holes, but what about them rivet heads?

I drilled through the splitter even though the rivets don't go through it. On the inside of that hole I used a big countersink to clearance for the rivet head. I could Bondo up the small holes you see but I won't. Only 4" tall midgets will see them.

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There's that perfectly aligned rivet...

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I also needed a new way to mount the welded wire trash screen that was sandwiched between the fascia and sheet metal in the previous version of all this. Hence the 4 bent tabs along the bottom for rivets later. There are also little corner braces on each end as the Roe duct side pieces seemed a little flimsy otherwise. Another Roe-Dave modification.

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It's back in for good this time.

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I drilled out the old rivet holes to allow for the rivet nut heads to fit in to and not on top of the fascia.

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Bingo. The parts pull up perfectly flat.

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Another piece that Roe provides with the duct kit is this strip that reinforces the chin spoiler. You know, that sacrificial lip under the front that you grind off over time on driveways etc. Now that I had recently powdercoated it red to match the car it is going bye-bye. No longer needed. Perfect timing.

The rivet holes from underneath will be reused. The ones seen from the front will have red rivets put back in until I get a fascia repaint and have them filled.

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Bye-bye...

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Next I cut out the pieces that will tie the majority of the fascia and splitter to the radiator support structure. Kind of some key important pieces.

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So why such a useless smartass pic then Dave?

 

[Tom F&L GoR]

Dave, no end caps for the opening? You have the pieces just underneath the fascia opening, but air don't always know it's supposed to go through the radiator and may escape by heading left or right towards the fog lights. Or maybe you're going to show a piece that blocks off the ends in the next post...

 

[dave6666]

Dave, no end caps for the opening? You have the pieces just underneath the fascia opening, but air don't always know it's supposed to go through the radiator and may escape by heading left or right towards the fog lights. Or maybe you're going to show a piece that blocks off the ends in the next post...

Those end caps will go on last. I do like to boss the air around with parts.

 

[Ratical2]

Dave, The quality of work that you are doing here is phenomenal and even more so because you are doing it all with hand tools. I have seen CNC work that did not look this good!

 

[dave6666]

Dave, The quality of work that you are doing here is phenomenal and even more so because you are doing it all with hand tools. I have seen CNC work that did not look this good!

So it's not the size of your machine, but how you use it?

 

[dave6666]

OK. Some useful pics of the parts that tie the splitter in to the radiator support structure. Pretty self explanatory, but a few comments and details.

-> I used 0.080 aluminum left over from what I made the diffuser blades from. That piece was 2ft x 3ft and I needed 1ft x 4ft. So I split the part in half. No harm no foul.

-> You can see 4 rivet nuts & screws on each side that go all the way through. There will be more along the Roe opening by the chin spoiler.

-> You can also see some smaller holes that will be rivets from underneath to make the pieces stay put when the splitter is removed.

-> The bent tab near the side of the opening is to mount the piece that will make Tom complete.

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[Tom F&L GoR]

-> The bent tab near the side of the opening is to mount the piece that will make Tom complete.

I knew you'd do the right thing.

 

[DAMN YANKEE]

David, that is just plain beautiful work. Seriously, seems a shame not to polish it all out and sell tickets.....

 

[Simms]

I like the shape you came up with for the splitter. Awesome work as usual.

 

[dave6666]

I like the shape you came up with for the splitter.

I'm hoping it will improve my sex life.


Really though, I gotta thank all of the members here that have posted pics of their cars and all of the car mags that have done the same, because without them I wouldn't have been able to copy that ACR shape!

 

[treesnake]

FWIW..
Looks really good Dave, IMO.

Your attention to detail and functionality (hope that's a word...) are obvious. You have thought this out and it shows. Not every one could dismantle their car and MAKE parts.

And for the references to "rice" looking etc...
Those people probably have never seen photos of the real GTSR Race cars...

What's next...Super Charger? Turbo??? Trailer hitch???..

All my cousins in Freona have trailer hitches...

 

[Tom F&L GoR]

I have a trailer hitch receiver on mine... probably fit right in the diffuser. Dave?

 

[dave6666]

What's next...Super Charger? Turbo??? Trailer hitch???

Siesta...








Aussi, Leslie et je continue un voyage romantique ensemble.
Nous ne pouvons jamais revenir.
Et si vous chiffrez que ceci dit c'est un mensonge !





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[dave6666]

All the rivets are in holding the big reinforcement panels on the inside and you can now see quite an array of fasteners. Still have to do a few along where the chin spoiler is, but total count of 1/4-20 screws going through the splitter into the support structure in (13) screws.

I don't think it's coming off, and there's probably six more screws to go. I will be putting gussets, if that's the correct term, at the wheel wells.

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This pic was taken before I even started and the reason I did was that it shows how in stock form the nose starts to ramp up a bit as seen on the bottom edge of the Roe duct sides. I needed that to be flat and not only cut that mounting tab off but also cut the bottom edge straight from the front to the back.

This pic also shows how the wire mesh trash screen was sandwiched in-between the sheet metal and the fascia. As has been mentioned, it is being relocated as to not be in a sandwich.

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Trimmed Roe sides in.

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I also put the fascia back on the car just to check and make sure there were not fitment issues from anything I had done so far, and it still fits like a glove.

 

[dave6666]

The trash screen is now riveted in. Fits inside the hole and not on top of it.

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I put some small washers under the rivet-nuts along that back edge so the splitter would bolt up at the correct sandwich thickness.

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With the splitter back on so I can...

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...clamp on a straight edge and draw a line to trim up the sacrificial chin spoiler lip. Cut off about 3/8". Looks much better. We'll see how long it lasts.

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Good view of everything inside the fascia.

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Closer inside.

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Next is to make the pieces that attach at the front of the wheel well opening, as well as a filler strip around the splitter fascia interface.

 

[Malu59RT]

Dave,

Never saw this thread until today, and I just have to say you are doing a kick @$$ job with all this stuff. I'm very impressed

Jason

 

[dave6666]

With the fascia done and back on the car I slapped on the splitter after first an hour or so with the router and sandpaper doing a radius number on the edges.

A couple of quick conclusions...

-> An olive drab splitter is not very becoming on my red Viper.

-> Needs the pieces at the wheel well opening in the looks department.

Clearance at the front edge is about 4-1/2" underneath. Driveway test manana...

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[treesnake]

Siesta... ​

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Aussi, Leslie et je continue un voyage romantique ensemble.
Nous ne pouvons jamais revenir.
Et si vous chiffrez que ceci dit c'est un mensonge !​

​

​

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That's what I thought...

 

[dave6666]

that's What I Thought...

お粗末な人． それを書いた時、私は酔っていて、欲情していました。