Does a Diffuser Need a Flat Floor to Work?

Today we continue the work on the diffuser vs cut bumper scenario, this time looking at if a diffuser works with a realistic (and quite terrible) floor geometry.
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[@slep5039]

Moral of the story is to do a muffler delete. Muffler seems to screw everything up

[@turdferguson9190]

Absolutely, would be really intresting to see an analysis without the muffler

[@0xXKARLOSXx0]

Turd Ferguson absolutely, thatd be awesome

[@extec101]

side pipe would be nice if it helps with achiving better downforce.

[@420atjh]

What's the best way to go if you're looking for the least amount of drag, like in a 1/2 mile race? I have an awd car and am interested in seeing the differences and best way to go as far as the combo of diffuser and flat-floors

[@JerseyMikeP]

Supercars... either run side pipes if front engine or central exhaust with mid engine.

[@MyLonewolf25]

Please do this 1 without the muffler 2 with side pipes 3 bumper exit or behind the front wheel exit PLEASE!

[@mm6705]

Nobody in their right mind does all the work putting a flat floor and/or diffuser and leaves the exhaust completely in the airflow.

[@palmermonsen9098]

in fairness it is usual because of regulations

[@WarriorOfEden3033]

For road cars yes you do. My long tube headers hang lower than my mufflers so I would say that’s going to be my biggest problem

[@atc576]

if your gonna do a flat bottom and a diffuser I don't think you're gonna keep the muffler. lol. Can you do the simulation without the muffler?

[@enzoracer5323]

up

[@johnnyvanformerwe882]

Hi Mr. Tell me how do you work? I have a single seater car that I am rebuilding and I really want it to be special. Can you offer any constructive criticism? Kind regards Johnny from South Africa 🇿🇦

[@davidaugustofc2574]

@@johnnyvanformerwe882 care to explain the project a little further?

[@KYLEENGINEERS]

15000 Subs, thanks for your support everyone! Enjoy the video!

[@miatamang]

Dude, thank you.

[@0ExG0]

Would be good if you do a table with he number and math just for better clarity.

[@DOO00K]

Ha! Over 105K now, including me. Great work and great that you're back!

[@soulshinobi]

Kyle, a personal mic like the Sony ECMCS3 ($15) might help a ton to minimize your awful room acoustics. Also get a carpet if you have a hard floor.

[@vanitatoftby]

+1

[@smvuy]

could you do a video on why some blocky cars are more aerodynamic than let's say, streamline era cars?

[@extec101]

thinking volvo 740?

[@YOURSCAPULA]

Great timing! I just got around to finishing the first video a few minutes ago, then I refreshed to find this lol

[@WarriorOfEden3033]

Need to see its effectiveness on a long vs. short wheel base

[@user-no6tp1ys3h]

Hi, first of all, thank you for the content, and thank you for truing to understand my english. Im understand that it is a technical or some sort of popular sincsific chanell, but your videos are so much better with phonk mix on a back ground:D

[@lur3950]

Kyle your videos are awesome. No doubt

[@djremotion]

Just found your channel and it is good stuff. I have already read quite a bit of underbody aerodynamics and diffusers, but I am not sure if I can get more from building diffuser than just cutting the bumper without it. I hope the cutted rear bumper is going to be featured more in flat floor video that I am wantching next. And I hope I regain better understanding of how much my floor can be cluttered to still be working like flat.

[@boblast5582]

I'm seeing more modern (last 15 years or so) cars have their rear muffler sideways so they can do a dual exhaust outlet from a single pipe. The muffler being sideways makes it more rounded to the airflow vs the hard 90* edges of a muffler like you have modeled. the Miata you use as your example actually has a sideways muffler like that. can you do a model with a muffler like that? comparing all 4 scenarios you compared in this video?

[@evillancer4580]

Great work, how would you work out the gain from a blown diffuser?

[@heyhayhay247]

I would like to see the diffuser and flat floor with out the exhaust in the way. My exhaust pipe routes above my diffuser

[@colaflaskan]

Do a video about rake with flat floor!

[@nickamarit]

Baseline, Baseline+Rake, Flat-floor, Flat-floor+Rake... 2 of them can be reused from the previous CFD analysis (Baseline and Flat-floor).

[@XxbenjabobxX]

Hey Kyle! What aerodynamic simulation software do you use?

[@rageu]

fucking awesome , thanks mate. this has been another informative , clearly explained and enjoyable lesson

[@darkdrakex]

To make a DIY rear diffuser, and possibly flat floor what do you suggest material wise?? I was debating aluminum but it seems like a pain.

[@krener29]

Nice video! Is it possible to use vortex generators on the diffuser to improve it? Wishbone generators are the most efficient ones?

[@0ExG0]

When I buy my Evo9 I will get a full flat floor and maybe a P1 diffuser copy. At least is what im thinking.

[@JerseyMikeP]

Need to run it with the tail pipes cut at the beginning of the diffuser start point...and see what the results would be.

[@pjgmorgan]

Nice one Kyle! Which turbulence model did you use?

[@ehsnils]

All your zooming and perspective changes of the pictures makes it very hard to follow what you try to present.

[@thomasmoura]

What turbulence model do you use in your simulations?

[@SaddMCB]

Hi! I was wondering, how does rake affect underbody flow? Specifically on a flat bottom+diffuser car. Hypothetical example where the wheelbase is 2500mm, front and rear overhangs 500mm each, front ride height 75mm measured behind the wheel and rear 100mm before the wheel. Are those proportions even worth considering? What rake would be considerable enough to go and adjust the underbody panels to keep them level?

[@FlyingHaggisRacing]

In regard to CN type cars ( front+rear diffusers+flat floor )... in years past the straight front splitters were often run very close to the ground, but now they often how a raised mid sections. Any rules of thumb to finding a starting point on how much air flow to have under the car ?

[@MaciekJutrzenka]

the raised mid section is for bumpier and race track with compressions and decompressions... so the car is more stable in terms of general grip.. so there is no situation of bottoming out with splitter cutting the airflow tottally.. and unsettling the car. look for example how new ferrari GT3.. etc cars have front

[@Swiftsuper1600]

If you had a floor which was flat with a diffuser, do you think there would be benefit to having small maybe 2" skirts running along the edge of the floor front to back or would it cause more issues

[@BrokeWrench]

Skirts would help by separating the flow from the sides and below.

[@bucketslash11]

can you do an aerodynamic analysis on the lamborghini special models (veneno, centenario, sesto elemento)

[@xXZ31t6esTXx]

Where does the wind go after passing through the radiator on the Teslas?

[@jacksonbermingham2168]

hasnt the rear wheel wake made a huge difference.. this is 2019 so time have changed?

[@WheezyCyclist]

when adding a flat floor the problem with engine bay venting, is it a bad idea to add a "step" with rearward slot in it to allow hot engine bay air out, I understand that ideally you would vent it out the top

[@BrokeWrench]

It's common to vent it out the bottom. You can actually improve downforce by using it as a jet along the surface

[@monolinkster]

Does a dish or a covered wheel do work for air flow or aerodynamics?

[@288gto7]

haziqrc's yes

[@shivamarora9916]

please name the software that you r using

[@nickamarit]

That revamped diffuser looks really Batmobile. :)

[@RallyRat]

The exhaust just needs to be extended a foot or so to the get the muffler in a lower velocity part of the diffuser...

[@the-real-zpero]

Now do another video without the muffler, maybe straight pipe and feed the exhaust so that it becomes a blown diffuser? lol

[@eliemaltz1221]

Why do you hide the software name?

[@jacklougheed4561]

What I’m hearing from this video is that I should straight pipe my car to improve aero.

[@Thesportynerd16]

cool stuff! what cfd program do you use?

[@skaltura]

I am surprised how tiny the effect is at 180kph ... Driving a low power timeattack car sure has it's drawbacks, can't get enough speed for some aero to make enough difference to justify the added weight and time to make the parts! :O Rules don't allow for full flat floor (can still make partial), but if we are going to see only something like 20kg from a massive diffuser which will by itself weight probably 10kg+ from low cost materials ... Or did you mean 11kg from the small section? full car would be twice at least ... Oh well, the good news is that i can scratch diffuser off the list until i know i will hit consistently above 200kph on most tracks

[@HellTriX]

I thought of this too.. Are these numbers representative of the half cut car or normalized to a full size car. I'd also assume approximately four times more downforce/drag for a doubling of speed as a rough guesstimate.

[@Tekvicious]

Answer is blown diffuser :)

[@karenchurton731]

I cant understand the point of the exercise...what else would you expect from simple aerodynamics

[@Luca-gu7qu]

you really would need an engineering degree/ studying one to understand this channel! My butcher doesn't know about the coanda effect! (nonetheless i love the content)