Hahaha that is awesome!!! I want to have to make one for school!!! haha

 

It appears on the one I posted that the exhaust is "somewhat" exposed to the air stream...at least from the trans to the rear of the car.

One of the other things you can do is install a heat shield in the tunnel. I found a source for gold heat shield foil a while back...a few sheets would be all you would need. Line the tunnel...and it would reflect the heat away.

I plan to use aluminum sheets on the bottom...I will probably get someone to stamp some louvers under the cats to extract heat away when moving. I won't have to worry about the fiberglass/injection molded plastic floor/tunnel on mine because it will be metal....required for racing.

 

I'm not sure how far you are into this project but if you have the chance which you might not I would really spend a lot of time on the cardboard skeleton. I would go out and really look for some triple or quad ply cardboard (THE THICK STUFF). It's a PITA to cut but your diffuser will last a lot longer. The only other option to add strength would be add a lot more fiberglass and that stuff is by no means cheap. The more time put in before laying the fiberglass the better, more durable, and better looking project in the end.

But keep us posted. Very cool stuff here.

 

Yeah, I'm still not completely done with the all of the glassing and resin, and I've gone through over $30 dollars worth of fiberglass and resin. And I'm still nowhere near being done with it!

And I've bought high-temperature paint for the diffuser. Do you guys think that will reduce a chance of this thing catching on fire from the exhaust? I have a fire extinguisher I keep in the car already, but I won't be too happy if this diffuser turns out to be Italian.

 

Okay, got some more progress done. The first layer of fiberglass on the underside of the diffuser somehow dried in such a way that it bent entire diffuser. So in order to fix that, we laid down a layer on the top of the diffuser and sewed some thread in with some of the excess glass and tied the other end to a paint can which pulled the fiberglass down while the top dried. It worked Now we can focus on finishing the glass on the fins this week. So I'm really hoping we'll be done with all of the glass laying by next weekend.

Here's the top of the diffuser with the glass on top of it:


Here's the string-and-paint-can method of straightening:


It's coming together slower than I would have hoped, but we're still ahead of schedule.

 

How stiff is it with just the top done?

 

It's quite stiff now! Though I wouldn't trust it under the car at the current state, but it's stiff enough to the point where it takes a considerable amount of pressure to get it to flex. Going to keep working throughout the week. I'll keep this thread updated as I go.

 

 

Wow, 16 days since I first posted this and already have over 1,000 views!

Anyways, apologies for the occasional updates of work being done. It's snowed every weekend for the past 3 weeks here, and it's almost too cold to work out in the garage. Though it was warm enough to be driving around with the targa top off last Tuesday..

I've got some work done since the last update, yet I haven't posted about it on this thread. I keep telling myself that I'm going to do it, yet keep pushing it off. But anyways, we straightened out the inner right fin, and it's standing straight up now. In the picture you'll see it how it looks right now. The left innermost fin is still crooked and I've yet to fix it. I have the fiberglass cut and ready to start on the left and right outer fins, and they should be done tomorrow.



EDIT: I'm going to be taking out the Dremel soon and making the diffuser look all nice an' purdy in the next few days. It'll look a whole lot better


-Jay

 

Oh, if you haven't noticed, the pictures are going to get a lot better now because my old Android phone broke. So I just upgraded to a Blackberry with a nice camera.

I will get the fins done soon, but I think I'm going to have to buy some more fiberglass to finish the other fins.

 

Been extremely busy working on school, other projects, etc. and I haven't had any time for working on this. I AM going to get more work done very soon and hopefully have all the fiberglass on by the end of the week. Then on to sanding and painting! The testing should come in somewhere towards the end of the month or sometime next month.

 

I just about fell out of my chair reading this.

 

By the way, fiberglass will NOT stick to packing tape (at least the brown shiny stuff). I learned this from a friend who used to build yachts, they would use the tape to wrap small parts used as "plugs". The fiberglass releases nice and easy and the surface would be really smooth.

 

Do not underestimate the amount of heat that an engine/exhaust will put off in race track application. If you have any sort of pocket around the converters it is going to be a massive amount of heat buildup... more than louvers will likely dissipate. Much of that is no doubt going to be transmitted right inside the car, even with heat shielding. The shielding will eventually reach a saturation temperature and will be ineffective. I had heat shielding all over the '96 and still saw interior temperatures as much as 40-50 degrees higher than most other cars that I checked... which was a big part of it being so brutal to drive. Putting a flat bottom on the car and preventing it from going out the bottom is going to make that infinitely worse unless you find a way to effectively vent it.

On the same note, don't discount the rear end. It NEEDS a lot of air to stay cool. If you build a flat bottom restricting that flow, you are going to need to add a substantial diff cooler.

Street temperatures are 1 thing... the temperatures that will be seen after even a short time on a race track are something entirely different. C4s put off a LOT of heat from a lot of different places. If you are not VERY careful when closing off airflow you are taking a huge risk of burning it to the ground or on a lesser scale, raising the cabin temps to insane levels.

 

I've been carefully mapping out what I plan to do, using Tommy Morrison's Snake Skinner and the Callaway SledgeHammer as a model...

I anticipate there will be some tweaking of concept though

When I spoke to Morrison while the R&D was going on...he said they eventually routed air from the front of the car into the tunnel to cool the interior. How that was done is anyone's guess...no pictures have been seen of the end result. A scoop extended down a bit to catch the air stream flowing under the car, or ductwork routing it there? Who knows...

What I CAN say is the belly pan gained him 15 MPH in top end...a significant change with no engine mods...just aero under the car.

As for rear differential...I'm thinking I'll model it on a Callaway Aerobody rear bumper.



Callaway used that for the SledgeHammer and had diff coolers mounted just behind both rear wheels...seemed to do the trick, but until it is actually installed & working it's just a guess that it'll solve it.

He also used it on the C4 LM Coupes...



A pretty significant diffuser under the back of that LM C4

If Callaway didn't want a bloody fortune for the aerobody kit I'd just go with that...but $9k for a "body kit" is pretty steep in anyone's book.

I've been keeping my eyes open for someone selling theirs off...maybe I'll find one or win the lotto.

 

Are you removing the spare tire?
What Mounting locations are you using?

 

[QUOTE
If Callaway didn't want a bloody fortune for the aerobody kit I'd just go with that...but $9k for a "body kit" is pretty steep in anyone's book.

I've been keeping my eyes open for someone selling theirs off...maybe I'll find one or win the lotto.[/QUOTE]

I heard that at one time there was someone in LA making the Callaway kits. Probably not for long though.

 

Yeah...hard to not draw attention to yourself...

After all, the lights are all different and Callaway is the only place to get them. I can see it now..."Hmmm, I wonder why this guy keeps ordering lights for a kit but not any bumper covers? He must be really lucky to keep breaking the lights and not anything else!"

 

I am going to keep the spare tire functional... Still have to design something to make that work tho

 

Here's one for you...



The 2014 Lamborghini Veneno...oh my.

They would be CRAZY not to use that as Batman's new "Bruce Wayne" drive!