Diffuser and splitter build pics

[mike & juli]

As others have said, and what I actually CALL you, Dave (SMART-ASP DAVE...heeheeeeee!)...you are ONE talented fella~! NICE work and illustrations/photos/explanations as always! ~jules
(OHHHH, tidying for a Leslicious visitor????? )

 

[ViperTony]

Not impressed...Dave should've been done by now....
































Just joking...As always, great work!

 

[Bugeater]

Materials....
I use Alumicore or Alumilite (I think are the brand names) and make front splitters with this material. Its honeycombed Aluminum. Comes in either 8 or 10mm. I have used both but prefer the 8mm. I was gonna make a rear diffuser outta the stuff and will be looking at your findings there! I buy the sheets at Harbor Freight on-line. Stuff is strong.

This is on my racecar - not sure if it has the asthetics for a street car, depends on how you cut the leading edge I suppose...

 

[dave6666]

Materials....
I use Alumicore or Alumilite (I think are the brand names) and make front splitters with this material. Its honeycombed Aluminum. Comes in either 8 or 10mm. I have used both but prefer the 8mm. I was gonna make a rear diffuser outta the stuff and will be looking at your findings there! I buy the sheets at Harbor Freight on-line. Stuff is strong.

This is on my racecar - not sure if it has the asthetics for a street car, depends on how you cut the leading edge I suppose...

How about a link for that stuff? Not Google friendly at this point.

 

[dave6666]

Did some material shopping today for the front splitter and so far have this:

-> 2ft x 6ft x 3/8" thick 6061 aluminum $400

-> 3ft x 6ft x 3/8" thick GPO3 fiberglass $200

-> 4ft x 8ft x 1/2" thick Extren 500 NOS $300

-> 4ft x 8ft x 3/8" thick Extren 500 $600

The 1/2" thick NOS sheet is a bargain from a supplier that would love to get rid of it, and it's the resin I would prefer to use if doing FRP structural sheet. However, I would also prefer 3/8" thick which is what the GPO3 is. Non preferred resin though.

Still shopping for the front splitter...

The rear diffuser has been trimmed and drilled so it will stay on it's own.

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You can see the gap between the diffuser and the bumper cover, leaving the rear exhaust hole still visible. No bueno.

In the second pic with my knee wedged under there pushing up, no more gap. A bracket will be built to accomplish that as previously pointed out.

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[RTTTTed]

When I planned on building the rear difuser Dave, my plan was to instal it against the trunk floor so that big air scoop behind the diff (your 2nd pic) would be an active air suction space.

I changed my mind because most of the effectiveness would be obstructed by the rear tailpipes. You went to side pipes and I though it was so you could cut that exhaust hole out of the rear bumper cover and build a more effective diffuser. Frame rail to frame rail and plate attached to trunk floor. Bigger rear hole = better aerodynamics. dunno?

Ted

 

[Indiana]

Nice work!

 

[jasontiff]

At first glance the rear bumper of a Gen. I and Gen. II are the same, but I haven't looked under the surface. I'm sure if they weren't you could fab something up to make it work!

That said, have you thought about snagging a good rear bumper off a salvage Gen. I car and starting the rear diffuser process without having to worry about covering the hole?

 

[dave6666]

When I planned on building the rear difuser Dave, my plan was to instal it against the trunk floor so that big air scoop behind the diff (your 2nd pic) would be an active air suction space.

I changed my mind because most of the effectiveness would be obstructed by the rear tailpipes. You went to side pipes and I though it was so you could cut that exhaust hole out of the rear bumper cover and build a more effective diffuser. Frame rail to frame rail and plate attached to trunk floor. Bigger rear hole = better aerodynamics. dunno?

Ted

I try to keep the "rewind" button in mind for all of this stuff. In other words, if someone wanted to return to rear exhaust, an original car if you will, there are only simple bolt-on parts to change, no un-fabricating or re-fabricating or...

Anyway, that's a lot more work than you think to do what you're saying. There's not much back there supporting the rear bumper cover, and a framework would have to be built to do what you're saying.

So for what's first a poser mod, and an effective aero mod second, I'm more than pleased with the effort versus looks so far.

 

[treesnake]

Looks Good...

 

[Fatboy 18]

Got to hand it to you Dave, Your not hanging about with this, Its all looking great.


Sunny but cold today

 

[Bob Woodhouse]

Beautiful and meticulous work. Do we have an overall plan here, IE what download numbers do you want to achieve, any testing or data available?

 

[dave6666]

Beautiful and meticulous work. Do we have an overall plan here, IE what download numbers do you want to achieve, any testing or data available?

A very good question, from what I will say is one of the alternate viewpoints. Yours being aero function - or the technical aspect of what I am doing - and yet another viewpoint might be quit trashing your car with bolt-ons!

Back to our viewpoints, as I pay no attention to the purists...

In short, my interest is as poser mods. The process started with wanting to cover the rear exhaust hole with a diffuser. Something that could be bolted on, and then removed later if wanted, with nothing remaining behind of the install. I did however, want to ensure I did nothing "aero stupid."

So I gave myself a class in race car aerodynamics via a very comprehensive book on the subject. What I got out of that schooling was not a bunch of numbers on downforce etc, although they tell you how to do all of that if you want, but alternatively I was warm and fuzzy that if I did not get carried away with these new parts, I would not cause upset to the car. For instance, a front splitter with a 3" extension (may even go less) is actually quite small compared to what you see on full out race cars. And my side splitters barely extend past the existing body features.

To close on the subject of aero enhancement, I would speculate there is some, although I will never measure and quantify it.

 

[mike & juli]

Dave---I am speechless! Can you believe THAT? WONDERFUL job...I LIKE how your rear looks now (lol). As always, attention-to-detail, and meticulous planning! ~jules

 

[treesnake]

A very good question, from what I will say is one of the alternate viewpoints. Yours being aero function - or the technical aspect of what I am doing - and yet another viewpoint might be quit trashing your car with bolt-ons!

Looks like your aero package is well thought out amd constructed with quality materials. I know you are, as most of us are, mostly street and occasional track drivers. Average speeds of 10-70 mph... or so. From what I have read, splitters, diffusers don't really start to work until you reach speeds of 90+mph... (That's illegal on the street...)

That being said, at the speeds we drive the most, your aero package achieves your intended purpose. A quality, "looks" enhancing, with some functional capabilities, body modification IMO

 

[Bugeater]

Dave,

Harbor Sales

http://www.harborsales.net/documents/MSDS- Omegalite, Alumalite, Econolite, D-lite.pdf

Here is a link to Alumalite. Google "Harbor Sales Alumalite" and you get other links like product specs, PDF's etc. They have other materials of interest. I ordered a 4' x 10' sheet for 185.00

My usage and priority was on the other spectrum (function over poser) so it may not do it for you looks-wise unless you devise a way of making the outer leading edge of the front splitter not look like it was "cut", since when you cut it you will see the corrugated (honeycombed) material that is used to sandwich the 2 outter aluminum sheets.

Good luck - wish I was as meticulous as you!

PS,
Hi Bob - nice to see you still post here - met you at VIR and then at VOI 10... I'm the guy from Papillion if that rings a bell

 

[Bugeater]

Here is what I used the 3/8" Black Alumalite for:

 

[dave6666]

To respond in some detail to the issue of honeycomb or laminated material versus solid materials, here are my comments:

-> Honeycomb materials are very good at being light, and maintaining rigidity as a flat plane. Those properties are good, but not the only thing I'm considering.

-> The cut edge of honeycomb can be "capped" to make it attractive, but honeycomb material will not be resistant to edge impact - it will crush. Like from hitting a parking curb or road debris.

-> The skin on these materials is very thin and therefore not puncture resistant. It can also be difficult to cut leaving an attractive flat non-jagged edge, without using a laser or waterjet to cut it. I use a jigsaw.

-> Fastening must be done more carefully as honeycombs can crush when bolted through. Fender washers, sleeves etc. must be employed.

None of these considerations apply to solid materials, but you sacrifice some weight. At this point, I'm willing to add the weight to get the part I want. I think the front splitter will be in the 15 pound or so range in solid 3/8" thick FRP. I am comfortable with that material and figure.

 

[RTTTTed]

Yah, Dave, with the parameters of "restoring the body" you're doing well.

I had planned to use 3/16" material and bolt it to the frame rails. Pretty simple, but cutting rear bumper cover and exhaust removal were required. After finding out that the exhuast sound can't be reproduced with side exit exhaust I cancelled my diffuser plans.

Way to go. ... White paint for all these parts? you know, to match your hood vents.

Ted

 

[dave6666]

Completion of the side splitters at the powder coaters delayed until mañana, so bust'a move on the rear diffuser again.

First step was to trim the plate to fit the contour of the rear bumper. I wanted about 1/2" extra, and marked it as such.

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Another test fit (you just cannot do that too much!) and the first pic shows it without being sucked up against the bottom like I want it. I took that pic just to show how it would look if you had rear exhaust and were only using the body bolts to mount the plate. Of course you would have to cut out for the exhaust hole.

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Pushed up with the floor jack.

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Next was to build the brackets that keep it up against the bumper but w/o the floor jack.

I had some 16ga 12" mild steel and made this piece that will mount to the rear exhaust hanger bar.

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Next was to make a bracket piece that would attach to the diffuser plate. The 2 brackets (one here, and the other one is the one on the exhaust hanger bar already installed) would be match drilled together in place. This bracket was of course fit and marked to the plate with the plate tucked up under the car. Then the plate was removed to drill the holes.

Fit, fit more, and fit again right?

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After fitting the plate/bracket assembly ONE MORE TIME, the 2 brackets were match drilled and the 1/4" rivet nuts installed in the upper bracket for bolting convenience.

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[RTTTTed]

Countersunk rivets or even dome head bolts would look nicer on the bracket Dave. Or, I' weld an aluminium bracket to your diffuser plate for smoothness.

I think you're just having too much fun and wish I was there instead of just adding my two cents. LOL

Ted

 

[dave6666]

Countersunk rivets or even dome head bolts would look nicer on the bracket Dave. Or, I' weld an aluminium bracket to your diffuser plate for smoothness.

I think you're just having too much fun and wish I was there instead of just adding my two cents. LOL

Ted

I will be using flat head (countersunk) socket head screws for the bracket.

Just like the saw cut edges aren't finished yet either, we ain't done yet!

And yeah, you're alway welcome to join me in this balmy Texas weather. 70 and sunny again tomorrow maybe? Again...?

 

[Fatboy 18]

I thought you would have had that done by now Its been almost 24hrs


Going down the pub

 

[Dave's Big Brakes]

Hey Dave,

You'd better get done quick as Big Brake Dave's sleigh is enroute with xmas goodies

Big Brake Dave
www.davesbigbrakes.com

 

[BOTTLEFED]

Great work Dave

when I was designing mine I wanted it wider so I could fit 4 blades across
I think mine went out about 2-3" more on each side

I think it will help to see how yours turns out so I can take some pointers from your project

 

[dave6666]

Great work Dave

when I was designing mine I wanted it wider so I could fit 4 blades across
I think mine went out about 2-3" more on each side

I think it will help to see how yours turns out so I can take some pointers from your project

Don't worry... It's getting 4 blades.

3 more...

 

[dave6666]

Side splitters are back from the powder coaters. 40 pesos more to their tab, making total cost of that part of this project about $150.

So I got out in the beautiful Texas weather and snapped some shots yesterday. I left the rear diffuser plate on as I wanted a good side shot of it on the car to pchop some blade profiles on there. That will follow later.

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[Bobpantax]

Well done Dave.

 

[GeneralLee]

Nice! Ill take a set.... Paypal?

 

[BOTTLEFED]

I think I have posted this before, but I just want you guys to be able to compare Dave's to some from a manufacturer (sorry my car was very dirty when I took this). Notice how different the angles are. It almost looks like mine are on backward, but the cutout for the exhaust means it can only go on one way. I like Dave's idea better.

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