Has anyone out there dabbled with under car aerodynamics
Discussion
As the title says I am thinking of trying a simple front splitter, undertray, and rear diffuser set up for experimental reasons.
I have an e36 328 track car & like to try different things every now & then.
I know the front splitter needs to be flat and level, protrude around 3 - 5 inches (I will probably try 3 to see if there is any difference rather than go too radical) to the front & beyond the tyres to the side. Ideally with canards at each end to prevent the airflow from going back under. I may also go for a couple of DTM style mini front wings.
With respect to the undertray, I also don't want to go too extreme, I just thought of starting at the splitter & ending at the diffuser with some ally sheet over the underside of the engine/exhaust/driveshaft/diff carrier to make the air flow a bit smoother to the rear diffuser.
As with the others, I don't want to go too far, but was thinking of constructing a simple venturi effect diffuser from the undertray to just past the rear bumper.
Has anyone tried this on their track car?
Is it liable to be worth it as a project?
I have an e36 328 track car & like to try different things every now & then.
I know the front splitter needs to be flat and level, protrude around 3 - 5 inches (I will probably try 3 to see if there is any difference rather than go too radical) to the front & beyond the tyres to the side. Ideally with canards at each end to prevent the airflow from going back under. I may also go for a couple of DTM style mini front wings.
With respect to the undertray, I also don't want to go too extreme, I just thought of starting at the splitter & ending at the diffuser with some ally sheet over the underside of the engine/exhaust/driveshaft/diff carrier to make the air flow a bit smoother to the rear diffuser.
As with the others, I don't want to go too far, but was thinking of constructing a simple venturi effect diffuser from the undertray to just past the rear bumper.
Has anyone tried this on their track car?
Is it liable to be worth it as a project?
spyderman8 said:
Filled mine with gravel twice - does that count?
Think you've got to be pretty careful with low-down stuff like that in case it gets ripped off and left on track. It needs to be so low to be effective that its *likely* to contact things.
Tee Hee! Dual purpose modification, I call that. 100 pounds of gravel, 100 pounds of down-force & the car is lower too!!!Think you've got to be pretty careful with low-down stuff like that in case it gets ripped off and left on track. It needs to be so low to be effective that its *likely* to contact things.
I know what you mean, I can't go too radical though as I need to clear speed bumps too!
I will be aiming for a little over 100mm as that is the regulatory speed bump height.
I will also be aiming to keep any protrusions below that (ie. fixings) both as minimal as possible, and of a type such that if they do come off, will not be of a type such that could cause a puncture.
The undertray I am planning to fit with Dzus fasteners & the splitter & diffuser will be bolted, not screwed on.
andyiley said:
As the title says I am thinking of trying a simple front splitter, undertray, and rear diffuser set up for experimental reasons.
Has anyone tried this on their track car?
Is it liable to be worth it as a project?
Yes and Yes. Has anyone tried this on their track car?
Is it liable to be worth it as a project?
I have LOADS of photos detailing my setup;). Here are a few. This has been an ongoing development. Initially it was all Aluminium with plywood splitter I`m part way through changing all that to Fibreglass at the minute, front splitter and Airdam is a one-piece fibreglass item and the floor / diffuser is under construction but that won`t be on the car for another month.
This started way back in 2011....
The flat floor was created from some 2mm aluminium sheet. The sheet was bent to add a `U` along the centre, this helped with exhaust clearance and also added rigidity to the aluminium .
Initial.
Secured numerous 6mm studs from the underside of the floorpan, made holes in the sheet to match up with them and secured the sheet to the underside of the floor.
On full lock, the wheels touched the sheet, so I had to reduce the width at the front of the car.
The exhaust was repositioned slightly and exits between the edge and first `vane`. I`ve added a `cover` to the top so it looks much neater.
Sprayed black and fitted, it looked OK, big but ok.
Looking under the car from the rear to the front, you can see the mounts protruding through the aluminium. These were trimmed.
Side on, the flat floor can be seen
A friend following me at the nurburgring saw Sparks and smoke from the rubber when the car grounded out.
Had a look under the car to check everything was OK. You can clearly see the water had been flowing nice and smoothly under the car, tapering back towards the centre of the diffuser.
Added to more vanes on the diffuser to try and keep the air linear
A more recent photo with reduced protrusions into the airflow.
Secured some rubber strips to the flat floor to try and keep the low pressure air under the car separated from the high pressure alongside.
This was during a day at Donington in 2012 where I`d raised the rear of the flat floor and the diffuser to increase the rake angle of the flat floor. Exhaust exiting under the diffuser roof rather than above it..
As the car was in March 2013.
Does it make a difference ? I honestly believe so. If it didn`t, I`d have removed it a long time ago.
When I just had the V1 splitter and no underbody or rear Aero, the front end was much improved, but the rear was very mobile. The floor and diffuser helps keep the original front > rear balance.
Edited by Wh00sher on Monday 20th May 08:34
Wh00sher said:
andyiley said:
As the title says I am thinking of trying a simple front splitter, undertray, and rear diffuser set up for experimental reasons.
Has anyone tried this on their track car?
Is it liable to be worth it as a project?
Yes and Yes. Has anyone tried this on their track car?
Is it liable to be worth it as a project?
I have LOADS of photos detailing my setup;). Here are a few. This has been an ongoing development. Initially it was all Aluminium with plywood splitter I`m part way through changing all that to Fibreglass at the minute, front splitter and Airdam is a one-piece fibreglass item and the floor / diffuser is under construction but that won`t be on the car for another month.
A friend following me at the nurburgring saw Sparks and smoke from the rubber when the car grounded out.
Does it make a difference ? I honestly believe so. If it didn`t, I`d have removed it a long time ago.
When I just had the V1 splitter and no underbody or rear Aero, the front end was much improved, but the rear was very mobile. The floor and diffuser helps keep the original front > rear balance.
Edited by Wh00sher on Monday 20th May 08:34
If you were bottoming out on a slight dip at the 'ring, I dread to think what happened at "the Carousel"?
I think I will not be going quite so extreme, and Whilst I realise that means I may lose some of the benefit, I have to be a LITTLE bit practical.
I was planning to smooth the underbody airflow out as much as is practical and source some rubber extrusion for the sides of the undertray to help keep the low pressure airflow in place, but that these be easily removeable, also a bit less radical (in the ground clearance department) front & rear.
Hopefully, I will get what I think I need together in the next month & get it on the way in July.
Watch this space.
andyiley said:
WOW!!! I take it the car is not road legal then, as I would think the MOT man would have something to say about it!
If you were bottoming out on a slight dip at the 'ring, I dread to think what happened at "the Carousel"?
Yeah, it was road legal. MOT man liked it If you were bottoming out on a slight dip at the 'ring, I dread to think what happened at "the Carousel"?
Carousel was grounding out, but not that bad. The loads in the Foxhole are quite high, it doesn`t bottom out often. UK circuits are fine.
Agree on that. I saw Whoosher and his golf at Bedford last summer. Great fun car and competitively fast too.
Top job on aero package!
My Noble has a flat floor but I filled the front area before the wheels, as have many other owners, to stop air build up in the front arches that creates lift. Much improved front traction as a result.
Some owners have added vanes to the standard rear diffuser style of Noble and no idea if it works but looks cool so I will follow suit at some point.
Case in point, Whoosher's golf. Looks cool from the rear with those vanes!
Top job on aero package!
My Noble has a flat floor but I filled the front area before the wheels, as have many other owners, to stop air build up in the front arches that creates lift. Much improved front traction as a result.
Some owners have added vanes to the standard rear diffuser style of Noble and no idea if it works but looks cool so I will follow suit at some point.
Case in point, Whoosher's golf. Looks cool from the rear with those vanes!
All TVR Chinaeras left the factory with a forward facing splitter under the car, about 15 inches back from the front. 99% get wiped off.
I put one back on my car. Sheet of stainless, 900mm long, 75mm wide, 45degree angle crease all the way along it, so splitter pointing down and forwards.
Sucked more air through the radiator, sucked the bonnet down, helped with steering grip.
I put one back on my car. Sheet of stainless, 900mm long, 75mm wide, 45degree angle crease all the way along it, so splitter pointing down and forwards.
Sucked more air through the radiator, sucked the bonnet down, helped with steering grip.
Scooby P1 said:
My Noble has a flat floor but I filled the front area before the wheels, as have many other owners, to stop air build up in the front arches that creates lift. Much improved front traction as a result.
I`ve recently made some fibreglass wings where I`ve increased the area ahead of the the front wheel 
and added vents to the rear of the wing to help vent the high pressure air from the wheel well. Usually, some of the air spills under the car, but with the flat floor, less air escaped that way, hence the requirement for the wing modifications.
Liking the rear bumper vents on the noble to help air escape from the rear wheelarches.
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