Aero modifications to low/modest powered cars - ?
Discussion
I'm just pondering if adding things like canards,splitters,diffusers etc are a waste of money or worth investing into for cars that don't have much power.
Lets say that the car already has excellent tyres, suspension and brakes.
I was talking a to a friend who races, and he thinks that on a low/modest powered car it wouldn't be worth it because the car is having to work harder against the air, so it will just go slower.
Surely people on here have experimented and will be able to say if it was worth it or not?
Cheers for any advice !
Lets say that the car already has excellent tyres, suspension and brakes.
I was talking a to a friend who races, and he thinks that on a low/modest powered car it wouldn't be worth it because the car is having to work harder against the air, so it will just go slower.
Surely people on here have experimented and will be able to say if it was worth it or not?
Cheers for any advice !
It can be worthwhile, because many aerodynamic modifications can reduce the aerodynamic drag on a vehicle. Areodynamics and CFD is an area I've worked in in the past, albeit for a short tyme before moving on.
If you're doing it from home, I'd avoid trying to fabricate a wing or aerofoil. These rely heavily on knowledge of the direction the air is moving in as it strikes the aerodynamic surfaces, and this can be very hard to determine without a lot of computing power and a good CAD model of the vehicle, or a lot of testing. Wings of a reasonable size usually add drag too.
The simplest things are an airdam/spliter and a NASCAR or Lancia Integrale style spoiler. The airdam/splitter if extended under the car to a mild diffuser style rise at the back can give massive gains in both downforce and drag reduction. My 3 series has a sheet of plywood extending from 6 inches in front of the bumper to the back of the gearbox. Coated in fibregalss for added stiffness, the first time it was used in anger it dragged the front bumper half off at speeds over 80mph. A spoiler will aid the splitter in forcing air under the car at high speeds. This will cause the dynamic pressure of the air under the car to drop and downforce will increase.
The good thing about the splitter/airdam is that it's practically impossible to get it wrong. For £30 worth of Ply/Glassfibre you can run a useful experiment.
If you're doing it from home, I'd avoid trying to fabricate a wing or aerofoil. These rely heavily on knowledge of the direction the air is moving in as it strikes the aerodynamic surfaces, and this can be very hard to determine without a lot of computing power and a good CAD model of the vehicle, or a lot of testing. Wings of a reasonable size usually add drag too.
The simplest things are an airdam/spliter and a NASCAR or Lancia Integrale style spoiler. The airdam/splitter if extended under the car to a mild diffuser style rise at the back can give massive gains in both downforce and drag reduction. My 3 series has a sheet of plywood extending from 6 inches in front of the bumper to the back of the gearbox. Coated in fibregalss for added stiffness, the first time it was used in anger it dragged the front bumper half off at speeds over 80mph. A spoiler will aid the splitter in forcing air under the car at high speeds. This will cause the dynamic pressure of the air under the car to drop and downforce will increase.
The good thing about the splitter/airdam is that it's practically impossible to get it wrong. For £30 worth of Ply/Glassfibre you can run a useful experiment.
Hi !
Well it certainly sounds like you've been experimenting
The car in question (for me personally) is an MR2 N/A (mk2), so it doesn't have a lot of ooomph but does handle and grip well.
I'm not in a position at the moment to go and buy a load of bits n bobs but I just wanted to do a bit of homework
Well it certainly sounds like you've been experimenting
The car in question (for me personally) is an MR2 N/A (mk2), so it doesn't have a lot of ooomph but does handle and grip well.
I'm not in a position at the moment to go and buy a load of bits n bobs but I just wanted to do a bit of homework
In a nutshell unless you are an awesome driver and have a track car set-up perfectly enough for you to notice tiny differences then don't bother.
You'll be better off getting your suspension set-up perfect.
Except........ As above a flat floor extending from your splitter under the engine gear box is cheap easy and does make a little difference. Just get a sheet of balsa wood from B&Q cut the shape out and screw it on.... You'll be surprised how many proper race cars have this. (oh and make a copy before you bolt it on so when you lose it on a kurb you won't havr to do it all again)
You'll be better off getting your suspension set-up perfect.
Except........ As above a flat floor extending from your splitter under the engine gear box is cheap easy and does make a little difference. Just get a sheet of balsa wood from B&Q cut the shape out and screw it on.... You'll be surprised how many proper race cars have this. (oh and make a copy before you bolt it on so when you lose it on a kurb you won't havr to do it all again)
flat floors will affect...
temps (particularly in mid-engine, also gbox, exhaust)
access (you can't get to anything easily)
damage - if you knock it off (particularly if it gets under the wheels at 80mph+ and you're near a barrier!
)
also don't work very well if over 27mm above the deck. certainly no groand effect.
Thats why we don't bother anymore anyway.
temps (particularly in mid-engine, also gbox, exhaust)
access (you can't get to anything easily)
damage - if you knock it off (particularly if it gets under the wheels at 80mph+ and you're near a barrier!
)also don't work very well if over 27mm above the deck. certainly no groand effect.
Thats why we don't bother anymore anyway.
groomi said:
Agree with the low drag comment. This is the direction I'd like to go with my Westie - with a CD of around 0.7 (I believe) there is a huuuuuuge room for improvement.
I'm told with a Sylva Striker (a 'Seven clone) and the Stylus (basically the same car with a full body) there's about a 20mph top speed difference spec-for-spec.So there is a huge room for improvement, but that's a very fundamental 'wheels in Vs wheels out' change, not a stuck on lip spoiler.
I think there are benefits to even quite minor lift reduction though. My MX5 went distinctly light on the front above motorway speeds and other people said they'd experienced the same thing, cured by a different splitter design.
Certainly professional drivers in purpose built competition cars claim to notice aero changes down to 30mph or less, so you don't have to be doing F1 speeds for it to work...
Chris71 said:
groomi said:
Agree with the low drag comment. This is the direction I'd like to go with my Westie - with a CD of around 0.7 (I believe) there is a huuuuuuge room for improvement.
I'm told with a Sylva Striker (a 'Seven clone) and the Stylus (basically the same car with a full body) there's about a 20mph top speed difference spec-for-spec.So there is a huge room for improvement, but that's a very fundamental 'wheels in Vs wheels out' change, not a stuck on lip spoiler.
I think there are benefits to even quite minor lift reduction though. My MX5 went distinctly light on the front above motorway speeds and other people said they'd experienced the same thing, cured by a different splitter design.
Certainly professional drivers in purpose built competition cars claim to notice aero changes down to 30mph or less, so you don't have to be doing F1 speeds for it to work...
1) Air deflector infront of windscreen, with modified windscreen mount so it can be removed when I arrive at the circuit.
2) Swap swept wings for cycle wings - maybe even some custom design jobbies to reduce drag further.
3) Rear wheel spats.
4) Custom made half doors to provide a bit of elbow room but still to clean up the airflow - possibly with something to help direct air around the rear arches.
5) Considering playing with the square rear end to smooth out airflow - maybe a simple boat-tail type arrangement enclosing the spare wheel and elongating the tail.
6) Adding a teardrop profile to the roll bar.
7) Flat floor with venturi - not for downforce but to smooth out airflow at the back.
Whether I'll get round to doing any of the above remains to be seen, as does whether it can be done without adding any weight overall...
I don't really know enough about aerodynamics to comment, but there are certainly some very heavily modified Westfields on the hillclimb and sprint circuit, bristling with wings and venturis.
It's also worth mentioned that, when it comes to drag reduction, the effects can sometimes be counter intuitive. For example, the little flick up spoilers you see on the back of some cars aren't there to produce downforce, but to tumble air down into the otherwise vacuous wake behind the car, reducing drag.
I'm a big fan of 'Sevens, but if you really want to improve the aerodynamics I'd consider swapping to something similar with a full body. That way you'll get a huge improvement 'out the box'.
It's also worth mentioned that, when it comes to drag reduction, the effects can sometimes be counter intuitive. For example, the little flick up spoilers you see on the back of some cars aren't there to produce downforce, but to tumble air down into the otherwise vacuous wake behind the car, reducing drag.
I'm a big fan of 'Sevens, but if you really want to improve the aerodynamics I'd consider swapping to something similar with a full body. That way you'll get a huge improvement 'out the box'.
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