[misc_work] Project 205 Diffuser

[Cameron 16]

I mean have it a little something like this:

 

 

Ignore the diagonal pink lines though, I was just trying to make it look 3D.

[wardy18 33 1 Cars]

That might work, maybe not quite as deep section for the exhaust, i need to box in the exhaust all the way down the centre undertray too, only a 4 - 5cm deep so to give the exhaust enough room to get through the tunnel, so i can carry this on through the diffuser until past the beam then get my 7deg lift started up to the back.

 

I have the ideas and pictures in my mind but getting it down on paper without a 3d drawing program is impossible

[Cameron 16]

I know, and it's even more difficult to try and explain that vision to somebody just in writing.

[BusEngineer 7]

If i remember correctly there wont be the room to get over the beam with the exhaust without cutting into the floor, and that in itself will be tricky due to the strengthening beam across that part of the boot floor/rear seat area.

 

Edit....

Only pics i could find of mine....

 

Apologies for the quality, phone pics.

Edited January 7, 2011 by BusEngineer

[wardy18 33 1 Cars]

Here's a sketch of what the diffuser looks like in my head, this is top view so if you dropped it from the car and sat it on the ground this is how you would see it

 

Diffuser sketch

[wardy18 33 1 Cars]

New pics of all the bracketing for the main upsweep part of the diffuser is now done, see the following link:

 

Brackets

 

Now to start cutting the sheet out and bending

Edited January 12, 2011 by wardy18

[wardy18 33 1 Cars]

The main panel of the diffuser is now measured and cut out, see link:

 

Main diffuser panel

 

As you can see the fins or strakes will come from the widest part of the car and narrow in between the suspension damper mounts so this will allow lots of air to be dragged from the full width of the car into the narrower channel thus speeding up the air, you can see the small bend at the wide end, this is the 7.2 degree angle lift, as you can the diffuser upsweep is very long ie 1/3rd of the cars length so should be very productive under there.

 

This has taken ALOT of time measuring and getting the most out of the space.

 

Now to fit this up against my brackets and secure in place so the side panels can be made from underneath the suspension damper mounts to cover them over, unfortunately because the upsweep cannot start until after the damper mounting the upsweep of this 13cm wide section either side will be 11.5 degrees but as its only 13cm wide each side this wont be much of an issue compared to the 79cm wide 7.2 degree upsweep in the centre.

 

Watch this space for more pics later on and over the weekend

[wardy18 33 1 Cars]

Main diffuser panel now fitted, just need to make and attach fins then make side sections to close in damper mounts, see my photobucket for new pics from today!

[large 33]

I don't normally follow project threads, but this one have me hooked! Awesome work, interesting topic all in all a fantastic job keep up the good work.

[harryskid 193]

Great work, love all the detail.Well worth all the time and effort!

[wardy18 33 1 Cars]

Thanks, I was almost to the point of ripping it all off and giving up this afternoon, got very overwhelmed thinking of the work left but then stood back had a clean up and got perspective of the job so far and what's left to do and got motivated again. I've spent more time on my back drilling holes in the last few weeks than a cheap hooker does in one weekend!!

 

It will be worth it...

 

Simon

Edited January 15, 2011 by wardy18

[qwerty 9]

Really enjoying the project thread mate good work, don't give up

 

cant wait to see finished product.

[wardy18 33 1 Cars]

Main fins to the diffuser now made and taped in place, see pics at:

 

Diffuser with fins

 

Now onto the side sections, trying to make these as simple as possible to get over the damper mounts and cover over all open areas but not as easy as it sounds at all.

 

Have also contacted a guy to tig weld all the parts together and get a professional clean job rather than the many lengths of angled ally to join the panels and hundreds of rivets. I thinks its worth getting it put together properly after all this time and effort.

 

Back to it wednesday night!!

[wardy18 33 1 Cars]

A morning of tig welding here we come!

 

Should have some good finished pics later today

[wardy18 33 1 Cars]

Pics in my photobucket account of the diffuser all built up and put together, all that's left is to trim then end down but am undecided whether to do a straight cut or curve it slightly to match the back contours of the car!!

 

Was very difficult to tig weld as the ally is so thin at 1.2mm so it didn't turn as good as I hoped but after a little seam sealer down the edges it soon tidied it up nicely.

 

Oh and it's only weighs in at 7.5kg, I'm happy with that!

[Cameron 16]

Looks good! I'm a bit unsure about the angled parts in front of the shocks though. There's a very abrupt edge where they join the large strakes that looks like it'll cause a lot of turbulence and could spoil the efficiency of the diffuser. It's a bit late to say now but I would have probably just ignored the shocks and left them exposed, then continue the main strakes forwards rather than angled them off to the side. Either than or have quite a large radius curve between the angled parts and the main strakes.

[wardy18 33 1 Cars]

I had wondered about curving these bit that would have made things alot more difficult when building, I can always trim the angled piece down level with the diffuser and just add in next extension to the main strakr to the front at a lot less Of an angle or even curve them in to meet it and just rivet these pieces in rather than tig welding them, would rather do it now than after.

 

I'll draw a sketch later to see if I'm on the same page as you

[Cameron 16]

Yeah I think we're thinking the same thing, extending the main strake to the front would be a lot less hassle than making a curved piece.

[wardy18 33 1 Cars]

My thinking as it is was bringing the air in from out wide and narrowing the channel and so speeding the air up through the main part of the diffuser, maybe I took it a little too far though, I was just going on previous advice in the thread.

 

Should the start of the strakes be wider than the main part of the diffuser at all or should the strakes be completely straight front to back? But then how does the get sped up?

 

Cheers

 

Simon

[Cameron 16]

The air is sped up under the car, between the floor and the ground, the diffuser just allows the air to exit cleanly. I hate using Wikipedia as a source of facts but this seems to be pretty accurate:

 

A diffuser, in an automotive context, is a shaped section of the car underbody which improves the car's aerodynamic properties by enhancing the transition between the high-velocity airflow underneath the car and the much slower freestream airflow of the ambient atmosphere. It works by providing a space for the underbody airflow to decelerate and expand so that it does not cause excessive flow separation and drag, by providing a degree of "wake infill". The diffuser itself accelerates the flow in front of it, which helps generate downforce.

Edited January 23, 2011 by Cameron

[wardy18 33 1 Cars]

So just to make sure im on the same drift here, see the following link, remove the red strake and add in the green strake yeh?! Im happy with this because then the air will also have free flow up into the side sections and wont have that angled strake in the way.

 

Diffuser Adjustments

 

I am currently applying the finishin touches to the main body undertay ie add in rubber strips to reduce resonating and exchange temorary bolts for domed allen bolts. Then add spacers to front undertray to flatten out any bulges at fitment points and add another couple of faster brackets to attach it to the front splitter then add the rear diffuser and a couple of side brackets which i havent done yet then its all done.

 

Next mission is work on adding the small dimma spoiler and look at the front splitter ends, the splitter gap is open at the ends infront of the front wheels so air is pushed through the splitter and then spoiled when it hits the tyre so i may add a piece in to stream the air out and around the wheels. Pic doesnt show very well but this patch would be curved to stream air.

 

Splitter adjustments

[wardy18 33 1 Cars]

I have decided to leave the diffuser as is for the time being, at some point i will drop it down and adjust the strakes, just at the moment it'll take a bit more work than i have time for, ie cut down the old strake, add in the new strake but then this will create a large step on either side of the diffuser so will need to be covered over to avoid turbulant air.

[wardy18 33 1 Cars]

Diffuser is now complete, just need to close off the gap between diffuser and bumper, going to either mesh this or a plate of ally with holes cut. We are now completely flat front to back as planned. Am starting to work on the exhaust now as this affects the diffuser and undertray. The exhaust tunnel needs to be cut into the undertray as there isnt enough room for the exhaust at the moment but this section of the undertray will be fitted back an inch lower but all depends how low the manifold swoops down so cant be done until the engine is fitted.

 

More new pics here:

 

Diffuser pics

 

[Cameron 16]

Looks really good.

 

How high is the back part?

[wardy18 33 1 Cars]

The back end of the centre strakes are 19cm high and will sit approx 10cm off the ground

 

I now really have to take care where i drive the car when on the roads, one supprise speed bump or pavement mount and its all over