I guess this is Performance Related too but I'll put it here.
I finally got round to doing something I always wanted to do, sort out a rear diffuser. I made it so it would fit if I go back to the standard or quad style exhausts.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/35932396_10160482523410084_95413785107365888_o.jpg?_nc_cat=0&_nc_eui2=AeGDLqFkDyu8Nyw7h_g2v00dvRFmjv3y9a11pX0P_LY2CfHiOmDYYtwuuEAK6QzN68d6A3ktROip5Z_KiT49cF8QZlxgTJxHSVTGLy23gAOniA&oh=c7ed97bd748a5d6acf121c2639d36a19&oe=5BE60817)
The original design was supposed to be fully 3d printed. It fits using the existing holes where the under tray goes and then to the bottom of the bumper. The base part sits level with the under tray and channel walls come down about an 1inch (at the front).
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/35156892_10160482523455084_7813877294883143680_n.jpg?_nc_cat=0&_nc_eui2=AeEzrOpUR3CiLjaQ8M8Gz6BDZRxFPFMm-iNkU2zcJmqIuQz2vE3-IDwuReEhAfOOnMja55re_EydclcEgMon0wARNTBMiacxHzMN5anYJCrqlg&oh=0234ee0b4dacfef9484a583afd9f98df&oe=5BAE18F8)
The I decided (at least atm) to make a mould and make the base part out of fibreglass (woven not matted). Printing this part would be cheaper but take a good day or 2. Fibreglass is quick to do, much more expensive but messy as hell. The channels are still printed.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36027117_10160482523565084_2858980023220568064_n.jpg?_nc_cat=0&_nc_eui2=AeHa026EJB4xfx3SizyK46a5C1geO2mHJ0dtcJStux5x6Z-FrP-y3PhubMbpHowCYofPukmwUaSVG1yC2WNM8d-BKB49kPxeDZ0Yu_y9W8jZjg&oh=af73cbf9978159a7f281701c22e14c6f&oe=5BA0F1F6)
I need to do something to straighten out the exit if the diffuser a little as the fibre has some flex to it (not a lot but it's bolted down).
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36136980_10160482523490084_3420991779690774528_n.jpg?_nc_cat=0&_nc_eui2=AeEQSqFq7LkQ38Zuad2CB1rdElxLReMWZfjerQos44WIjIE1CNlw4U-PRIgP02jq1ZJ7IQbz7LLP9UxIEnf8lxSFt9bVR3eg6e0ieLACpdubug&oh=cba3120b2ea0cd3576432bf4f6534507&oe=5BAB45B5)
The channels did come down another inch or so but I was really doubtful they would make a speed bump. They are quite strong but the idea of making them as a separate is to be able to easily replace them if they do take a knock.
Now I need to make a part that bolts onto the front of the diffuser, (using the existing holes and slots into slits made in the under tray) with channels to screw onto the under tray. This should then allow a more smooth transition the air onto the diffuser. Then I need to make sections to channel the air from the sides of the wheels and down where the exhaust(s) exit and spats would be.
Always an interesting read.
Looks good.
I like it a lot
Thanks guys. It actually didn't take too long to make once the fibreglass mould was done.
Plus I've been driving around without a nappy and showing my arse for years. Looks loads better now the CAT is covered.
Something like this, so it slits in part way down the engine under cover
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36087980_10160484580430084_2680062904123785216_o.jpg?_nc_cat=0&_nc_eui2=AeFzPxPJAR1qswnAg8bMxYFz4s1qlYoInF5g1x9coUTUt9sXM5-S861pnPkgFFVRtURFCU5yWZ374BFqtqhNXCm1ca84zeDI5Y5uBiwtRbiopg&oh=5aa0780d8628da9edf7c8930a38d318a&oe=5BA2C99F)
I also just took a few measurements. The bottom of the channel sides are 100mm off the floor at the front (this is about where the wheels are) and 140mm at the rear. If i make it 100mm all the way along (I was hoping to keep them straight as it creates a bigger expansion chamber & increasing the effect), I'm sure it's going to knock speed humps as I come down them. ::)
Have you completely removed the undertray?
Quote from: StuC on June 25, 2018, 23:01
Have you completely removed the undertray?
The one that is normally around the CAT, I never had on. The one that's under the engine, this will (at least for the moment) be incorporated onto.
The whole floor plan really should be as flat as possible but it's so much work to do that now I've sold my 3D scanner, I doubt I'll get around to doing it.
Agreed you need a fully flat floor for maximum benefit. Ikrana had the closest thing I'd seen to a full installation.
Having the forward one, will deffo help. If you'd removed both I was gonna post about the futility of it. Lol.
Also... seems ages since I have seen any pics of your car!!
I'm hugely interested in aero. If you look up a a youtube channel called Kyle.engineering then you can see his stuff on aero. In his explanations a flat floor is THE best thing you can do at low level aero.
I've been speaking to streetwerks and they're working on this.
But...I have an angle grinder. A four post lift. A lot of cardboard. And threaded bar.
I reckon I can replicate a better version...if a little rough around the edges.
I'm currently snowed under....but progress will be revealed in due course. I
I've been about but only really fitted a UD sub in the past year. Not done much else to it since... I did make these tho:
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/17498945_10158427824385084_2586034427666831572_n.jpg?_nc_cat=0&_nc_eui2=AeFfK6t99_PYBNfANM3KvmJ-pcUpAvS6c268DRvsQWNXqwbzoqHluaR_vwnBQRuShc6zBFLmfSuT1OZj92OyI5GqLOAu7hb6TQQr8pMgcQKSAw&oh=db6357dde43e87e1aac76b4046f83b1d&oe=5BE93151)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/17499121_10158478797350084_6624698999974685687_n.jpg?_nc_cat=0&_nc_eui2=AeEQ5ypwL_AYM9d741GtohmP0YmDMs5Avz7bgVz-KX-o7eseZ6-UhytB9cm_7h0CX9ItwAH9HJWcL1ancK6Aqxr4sQGSPbRY2lUVj6a1RQT6WA&oh=300dbca708761735754baffec57a8913&oe=5BA3403A)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/17626223_10158442848295084_8326108126765799124_n.jpg?_nc_cat=0&_nc_eui2=AeEzn5G7ybunsETMyvpgBZtiJkH7c2S0mcRviVHViYBQb6-EGnfHe2SRc0j1E-tfYc1-mV220ZVzMYcDuJgl_RJbJtKbnmp7CL_U-mWDBtEnSw&oh=225d8f052c7455b3cd4d364dda551a1d&oe=5BAE0EA8)
and my second version:
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/18056941_10158567563975084_8002094412399723799_n.jpg?_nc_cat=0&_nc_eui2=AeGSdcX34nHBnbcetMps7avORHrfpYJpbpgcNmPkY1MhLR331anRzXrhSAHjcuFPEA56QWYd4sG5u3Q-dTrvHkRWqYzeZKPUZq3QaswdCgXN9g&oh=9b86f3a398e47ed0dbe6a09e8838b761&oe=5BAEDCE5)
The main thing, apart from getting the design done, is trying not to have bolts sticking out (you really are pissing into the wind doing that!;) ) and being able to get the thing on and off.
Driving about without covers really is like having a parachute open so I think that just the back part will have quite a considerable benefit. Ideal would be at least middle of the car back as it will give the air a lot of chance to settle and get back to the same speed as the air going over the top of the car.
I downloaded software that runs airflow and pressure simulations as I want to see how it's effected it but don't have a CAD file (or SLI) of the car.... yet
Made some new channel walls.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36754180_10160534667040084_1977738087966441472_n.jpg?_nc_cat=0&oh=75124d4a802b0fd625d84ffdc67ae5b9&oe=5BE1B76E)
These are a lot longer than the old ones so now they're 100mm from the deck. I've been over speed bumps ok (tho it must be close). They're stronger with 2 sidewalls and print in half the time thanks to some new printer settings (about 3 hours each rather than 6)!
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36809902_10160534666915084_7249029472723140608_n.jpg?_nc_cat=0&oh=f17472abbf2a7df9d44bd4dcb30d9507&oe=5BDD5BF1)
Ready to start printing the bits that go from the undertray and channels from the side of the wheels.
Think I'm about there with the drawing
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36905710_10160542993930084_6088085106646319104_o.jpg?_nc_cat=0&oh=41c360e36aee090aeb294c9b53c80a16&oe=5BE35A24)
I can make the side two run out as they should because the CAT isn't in the way.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36897134_10160542993920084_6324833689800802304_o.jpg?_nc_cat=0&oh=0ec678437707211c49a887c7e79f690d&oe=5BDE704D)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/36929701_10160543272085084_8623069302615965696_o.jpg?_nc_cat=0&oh=c12df7a0fe8ebcecf13f5664b722152c&oe=5BA54E91)
From what I've read, this will create more vacuum and again, less drag.
Hopefully I will have time to get it done before I go to sweden in 2 weeks :D
These are a thing of beauty!! Love it.
The design is quite nice and its going to work the way its setup. Just an idea, cant we cut the bumper up and make the curve of the diffuser start a bit earlier. That way the gap between the ground and the ending of the diffuser will be bigger and bonus the fins can be shorter and not getting broke when coming down from a speed bump. It will also work better with bigger gap.
Quote from: Nvy on July 10, 2018, 08:14
The design is quite nice and its going to work the way its setup. Just an idea, cant we cut the bumper up and make the curve of the diffuser start a bit earlier. That way the gap between the ground and the ending of the diffuser will be bigger and bonus the fins can be shorter and not getting broke when coming down from a speed bump. It will also work better with bigger gap.
Thanks for the input guys.
I wanted to start it where it bolts onto the 2 rear under-tray bolts (on the sub-frame) so I could take it on and off easily and fit these with as little modification to the original as possible without gimping what I'm trying to do. From what I read if the exit angle is too great you're going to increase drag and then we're looking at about 70 odd deg over a fair few inches.
https://ac.els-cdn.com/S1875389211006924/1-s2.0-S1875389211006924-main.pdf?_tid=7914888a-b906-435b-9ba6-ce36bd368c04&acdnat=1531213775_10cf6186b46c3cc2a20dc877035997cc (https://ac.els-cdn.com/S1875389211006924/1-s2.0-S1875389211006924-main.pdf?_tid=7914888a-b906-435b-9ba6-ce36bd368c04&acdnat=1531213775_10cf6186b46c3cc2a20dc877035997cc)
I know the case will be different as the Mr2 has a different aerodynamic profile. I really need to look at the simulation programme I downloaded!
So doing this could defeat the object. I'd have liked to have a rake on the centre section but that would mean the original CAT wouldn't fit. I wanted to keep it so it could fit with the standard exhaust setup.
I'm no expert with designing these things, I'm just going on what I've read. That's was what I had before. At the start, 100mm from the floor and at the exit 140mm. Again, in an ideal world the air needs to be kept as uniform as possible reducing as much turbulence as possible. Having it leave the diffuser half way down it (because the angle is raked) could mean it creates turbulence. Again, I would need to run some simulations to test.. It's now 100mm and 100mm. I've been over quite a few speed bumps over the past few days, all good so far! :)
The YouTuber Kyle.engineer said a good generic roadcar aero setup was to have a flat floor with 25mm rake from front to back wheels and then to have a diffuser angled up at about 10 degrees.
If you don't know him he has now closed his YouTube channel because he got an aerodynamicist job at the AMG Mercedes F1 team so I think he knows what he's talking about!
Quote from: lamcote on July 10, 2018, 14:12
The YouTuber Kyle.engineer said a good generic roadcar aero setup was to have a flat floor with 25mm rake from front to back wheels and then to have a diffuser angled up at about 10 degrees.
If you don't know him he has now closed his YouTube channel because he got an aerodynamicist job at the AMG Mercedes F1 team so I think he knows what he's talking about!
I watch his stuff.
Realistically I think a flat floor will give the biggest benefit to our cars due to speeds etc. And a splitter or air dam at least.
Someone is making these on the FB page but I cannot remember who. Believe it may be Meguillian motorsport?
Quote from: dan944 on July 10, 2018, 15:17
Quote from: lamcote on July 10, 2018, 14:12
The YouTuber Kyle.engineer said a good generic roadcar aero setup was to have a flat floor with 25mm rake from front to back wheels and then to have a diffuser angled up at about 10 degrees.
If you don't know him he has now closed his YouTube channel because he got an aerodynamicist job at the AMG Mercedes F1 team so I think he knows what he's talking about!
I watch his stuff.
Realistically I think a flat floor will give the biggest benefit to our cars due to speeds etc. And a splitter or air dam at least.
Someone is making these on the FB page but I cannot remember who. Believe it may be Meguillian motorsport?
Id love to have flat floor and lowered to the ground car but lifting kits are rly expensive so i wont be able to go on speed bumps :( Other than that, i would like to get in the line for a diffuser:)
I went bump hunting again on thurs, no issues still. I wouldn't want to go over the smaller type (that are in pairs) but I had to drive in-between them already anyway so no biggy!
The first set of sides are printed and test fit ok! I took some pics before I paint them so you can see the curve a bit better. The outer ones are coming out now. I've made these in black as I assume they're going to see some grit from the wheels. That way I don't need to keep re-painting them :)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37098448_10160561532530084_816794499278700544_n.jpg?_nc_cat=0&oh=e75845ea2518ee9facea548c3dadde56&oe=5BA200C2)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37179895_10160561532355084_4747303265815756800_n.jpg?_nc_cat=0&oh=4726e0bc8680faec4466966cac47aa69&oe=5BDCC47A)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37177572_10160561532435084_9221157135105130496_n.jpg?_nc_cat=0&oh=94cd2348cf3608315cd1fb643eba1b51&oe=5BE4A97B)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37107536_10160561534005084_594248260575559680_o.jpg?_nc_cat=0&oh=abcce8f4a23349b83d79ac498491d71f&oe=5BD2ED88)
I actually went into a plastics place where I brought sheets for my 3d printer and asked if they had any ABS. They had a sheet of 2mm. It was expensive (weight for weight) compared to what I print with but it saves massive amounts of time doing flat surfaces. I wish I'd have gone in there before I started because I'd have done the main body in this rather than messing about with fibreglass!
I might actually have enough left from this sheet to make a duplicate diffuser so I'm going to give it a try in this too rather than the fibreglass.
So all was fitted and looking good (car jacked up in the pic)...
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37338458_10160576473250084_4940082619493646336_n.jpg?_nc_cat=0&oh=c13cf17b8225a1f7e5d8a0e635ece167&oe=5BCEC56B)
But I had a problem...
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37145283_10160576473375084_608899326030118912_n.jpg?_nc_cat=0&oh=481033f0457179bd11b3002cb783693b&oe=5BD6AC95)
once it's jacked up the diffuser clashes with suspension components (:< >:)
I removed the outer section and made the brackets to hold up the front.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37286631_10160576473495084_3611325364241956864_n.jpg?_nc_cat=0&oh=c35c3bf969d0b2c1102dece4155e72ea&oe=5BD26C0E)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37290301_10160576473595084_2762774997763096576_n.jpg?_nc_cat=0&oh=3574a2ab9d546ac8af81dc9cd1390e51&oe=5BD00932)
I've kept the outer channels and the plan now is to either start to font of the outer channels later or slot the diffuser so the suspension components can down down when the car is jacked up.
I don't think I'll be able to get this done before I go on holiday now.... I had a big box delivered today with my new side-skirts in :-* I don't really want them hogging up all the space in the shed while I'm away when they should be on the car.
*edit looking at the pictures I think the car actually looks better without the outer channels.
Agreed looks better.
Good work.
Same. If you get some rear seats on there it would blend in lovely but I think would be counterproductive to the aero.
Quote from: dan944 on July 18, 2018, 13:21
Same. If you get some rear seats on there it would blend in lovely but I think would be counterproductive to the aero.
Assuming you mean "spats" I was thinking the same, diffuser looks lovely but just missing that finishing edge like spats.
Sent from my iPhone using Tapatalk
Quote from: Call the midlife! on July 18, 2018, 14:38
Quote from: dan944 on July 18, 2018, 13:21
Same. If you get some rear seats on there it would blend in lovely but I think would be counterproductive to the aero.
Assuming you mean "spats" I was thinking the same, diffuser looks lovely but just missing that finishing edge like spats.
Sent from my iPhone using Tapatalk
Yes...yes I did haha
Quote from: dan944 on July 18, 2018, 14:38
Quote from: Call the midlife! on July 18, 2018, 14:38
Quote from: dan944 on July 18, 2018, 13:21
Same. If you get some rear seats on there it would blend in lovely but I think would be counterproductive to the aero.
Assuming you mean "spats" I was thinking the same, diffuser looks lovely but just missing that finishing edge like spats.
Sent from my iPhone using Tapatalk
Yes...yes I did haha
Although you're right, some seats on there would really mess with the aero.[emoji23]
Sent from my iPhone using Tapatalk
Rear seats would go some way to quashing all those criticisms that the 2 isnt practical.
Otherwise, rear spats would look damn good...
haha rear seats would be good but he reason we have an mr2 is because the engine is in the correct place! ;)
I thought about putting in some spats (or something similar) but that's really counter productive. Function over fashion ;)
I've still not looked at this software yet... I would also need a CAD model of the mk3 (or draw it up myself). Looking at simulations from other cars, it seems being half closed half open is probably the middle of the pack. As an open cylinder (like an F1 car) creates turbulence behind the tyre.
Putting on a spat is like having on a parachute.
Looks like ideally the bodywork should be flush with the outer face of the wheel with a in and out diffuser channel directly behind the wheel from the inside to out. This would normally vent the rear breaks too I would imagine.
I've never even been on the track in my car so it's not as if my ideal goal is to be able to go around hammerhead at 90 ;)
Quote from: Mr X on July 18, 2018, 16:40
haha rear seats would be good but he reason we have an mr2 is because the engine is in the correct place! ;)
I thought about putting in some spats (or something similar) but that's really counter productive. Function over fashion ;)
I've still not looked at this software yet... I would also need a CAD model of the mk3 (or draw it up myself). Looking at simulations from other cars, it seems being half closed half open is probably the middle of the pack. As an open cylinder (like an F1 car) creates turbulence behind the tyre.
Putting on a spat is like having on a parachute.
Looks like ideally the bodywork should be flush with the outer face of the wheel with a in and out diffuser channel directly behind the wheel from the inside to out. This would normally vent the rear breaks too I would imagine.
I've never even been on the track in my car so it's not as if my ideal goal is to be able to go around hammerhead at 90 ;)
Haha. I get what ya mean though. Again looking at Kyle.engineers work on the tube it can be seen that when he studies it wheel cut outs provide good aero.
I forgot I had a pointcloud..
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/37348117_10160579882180084_7917171949841678336_o.jpg?_nc_cat=0&oh=f5f03137be7aa66bfa95674db1b1c556&oe=5BD0007E)
Talking about spats reminded me I took a scan of the rear corner back when I had a scanner. Just in case I ever wanted to do something with it.
I'm sure something will be on the cards once I'm back from holiday :)
I just thought. I could just not jack the car up with the edge parts of the diffuser on?? :-\
I'll see if I can find some pictures of my racecar aero set-up.
That had a full flat floor with a splitter and diffuser incorporated.
Quote from: twiglett on July 25, 2018, 09:12
I'll see if I can find some pictures of my racecar aero set-up.
That had a full flat floor with a splitter and diffuser incorporated.
This is what I want!!
From what I gather it's the flat floor that will give biggest gains on a road car.
This is a good read... You guys do know that Laurence does the aerodynamics modelling for Williams? Lgriffiths I think- you should ask him for his input as I reckon he's rather qualified...
Sent from my Moto G (5) using Tapatalk
Nice to see some DIY aerodynamics, kudos for finding the motivation to make some physical parts! All I can advise is find a way of viewing the probablem so you can see if you've fixed it. What simulation software you using?
You've managed to fit in a lot of fences. If you simulate it experiment as well with taking a couple out. it's worth examining the area evolution through the diffuser, flow won't take kindly to rapid area expansions, if there are any. At a guess I would imagine the flow in that central section around the cat will want some support though, likely to separate without it.
Try some DIY aero tests... if you can find the time. Could mount a camera looking at the diffuser, stick some wool Tufts all over it and do a video. Or mix up some flowviz paint, just don't do it near your house, that stuff is messy.
Sent from my Moto G (5) using Tapatalk
Thanks for the input. I'm actually on holiday at the moment. I took the car out for a good drive on Monday (I left on Tues) and it felt a lot more planted, especially on roundabouts. What I need to look into now is the angle of the exit around the CAT, as you say. This however does become a problem because from what I understand (I didn't take a course on this stuff or goto collage etc lol) the angle that flow separation occurs depends on the speed of the airflow as well as the height of the car, air temp etc. So really it has forever moving goalposts on a road car.
It's easy to overthink it. Best practice will sort most of it.
With any aero you need to decide if your going for low drag or high downforce.
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ok, my re-design is done to comply with the 7-11deg suits most cases angle.
The CAT can be seen in this one and red part is the bottom of the original bumper.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/38997006_10160675020025084_9146462753270005760_o.jpg?_nc_cat=0&oh=7872e02c52c5c8ee487ccdeda43e2bee&oe=5BC88F7C)
Unfortunately it means I need to re-make the whole thing as none of the first version is re-usable.
got quite a length out of it without getting any closer to the CAT. I extended the diffuser out in the middle by 40mm to give it a bit of extra height. I left the dropped section open to draw heat out of the engine compartment.... If i block this section off I presume it would create extra drag.
Nice solution to getting around the cat issue, and yes I think leave open too, good for cooling. Would be really interesting to measure massflow through the enginebay with this open and blanked off, I'd expect blanked off to be much worse.
Another option you could try to step around the cat is a double diffuser design. That way you won't expand too aggressively.
Miles better than the nappy!
Would be fun to flow Vis this against the stock nappy.
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Thanks.
Yeah, I'm guessing the effect of the airflow leaving the diffuser would cause a suction effect on the air leaving the engine bay. If i was to blank it off that suction would then cause more low pressure. My exhaust exits to the left right side of the number plate and I read that that will reduce drag as area as I'm effectively pumping air into the low pressure zone.
I've already thought about that too as now I have the exits above. I could channel it from left and right of the engine as there's quite a lot of space there around the suspension components. I'd have to slot the channels as when I jack the car up or go over bumps, the suspension & drive shafts need to be able to move up and down.
I agree, I would love to see what difference its made (I'm presuming quite a bit) but I've been spending time designing and re-printing other stuff for the car rather than looking into openfoam. ::)
You can measure drag using coast down tests , just need a stopwatch and some paper, and a bit of maths. It's important that there's no wind, and take a large sample going in both directions.
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Ok, so the newer version is on and I'm quite a happy bunny!
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39876141_10160710184780084_1228533025168424960_n.jpg?_nc_cat=0&oh=f36b60ab5dde2fc80c3b83cd5a77878d&oe=5BF39AA3)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39786415_10160710185525084_5703904486792101888_n.jpg?_nc_cat=0&oh=8fce8cdbbda053ed073763b6430ebf46&oe=5C01314E)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39918022_10160710184965084_7586646032839081984_n.jpg?_nc_cat=0&oh=32eb89157164110a39f364c6a72d8f46&oe=5BF4C35E)
self tapping screw just a little off to the left here causing the bulge where the undercover meets it on the right!
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39760468_10160710185130084_1702589838600962048_n.jpg?_nc_cat=0&oh=ed27f037df8fea16647f6a337e7b2868&oe=5BF32FC9)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39814269_10160710185290084_7099974269098000384_n.jpg?_nc_cat=0&oh=6fb57166121e0ee4d1c15f47a823cd13&oe=5BF2C233)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/39914722_10160710184630084_7368696495769387008_n.jpg?_nc_cat=0&oh=ecc16f3a9482c93eae60cf3b7300411c&oe=5C0D355F)
The extra 100mm I put on the inside means the centre sections meets up with the undercover very nicely! Although I didn't quite put one of the screws in the right place and it's warped the flushness it a little (i'll have to fix that).
Now I just need to add a longer extension to the outer sections of the diffuser (so it meets with the outside of the undercover), think about how to finish off the outer inside so air cannot get in from the edges and make sure the exhaust doesn't melt it :D.
ok so, another quick update.
The diffuser has had no problems with the heat from the exhaust, the foil has worked very well and I can put my hand on it after a good run.
I made the new version of the side extensions with a sweep up to 11deg and a colour swap:
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/40615451_10160755986355084_9165012751381168128_n.jpg?_nc_cat=0&oh=90bcf75d3f51353481a51325b1636b18&oe=5BEF7B3E)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/40758254_10160755986485084_3339383793294245888_n.jpg?_nc_cat=0&oh=ffccb7e6c0d836a9854434fe80abf367&oe=5C291C25)
As you can see, I extended what will be the flat section so it runs along side where the engine cover is. It reaches all the way to to covers beside the fuel tank and sits under them quite well.
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/40638535_10160758782215084_8540907385697337344_n.jpg?_nc_cat=0&oh=e5f6e508f8739446a4c2501a9cfc5ea3&oe=5C2C426B)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/40645179_10160758782310084_1054094066607718400_n.jpg?_nc_cat=0&oh=f6a2942f4ac3a7a1308fd4e6c854cc70&oe=5C35E566)
(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/40772908_10160758782135084_1195862274099642368_n.jpg?_nc_cat=0&oh=3ae4ca3fecda1a6fb8daf51539290ca0&oe=5C30804C)
The piece you see on the floor is the part that's going to replace the engine under tray. It reaches all the way past the fuel tank and to (what's left) of matt's brace.
This is too far for this section I think. I'm going to make it end at the fuel tank. That gives me some nice points to mount the start of this tray on. Then I can, if i wish, flatten off the fuel tank and matt's brace in 2 separate sections.