Aero improvements

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HampusSoder
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Aero improvements

Post by HampusSoder » Thu Sep 24, 2015 6:51 pm

Hello!

I've started to become more interested in improving the aeoro of my puma! I already have a front splitter that will hopefully be fitted next week! :)

I know the basics of a splitter, it creates a low pressure which forces the air under the car and forcing the front down.

Thanks to Sjoerds aero thread I've seen that the Puma creates some drag in the rear. I'm no expert but I think that's happening because of the air travelling in too slow speed behind the car which generates the drag. My thought is now that fitting holes in the bumper (and working with the splitter) would solve this to an extent.

Theory: Splitter forces front down and sends air under the car, the air under the car finds its way through the holes in the bumper and put some speed in the slow air on the rear and reduces the drag.

I could be talking shit atm. I'm not educated in this.

am I just totally talking bullshit or do I have a point?

Any help on this is helpful! :-)
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adrianm
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Re: Aero improvements

Post by adrianm » Sat Sep 26, 2015 8:55 am

Personally I think all the splitters, holes and spoilers make a tiny if any difference and in some cases could actually slow the car down.

They just don't go fast enough to need all the fancy aero bits.

If you've got the best suspension, best tyres etc then it might be worth the effort but IMHO the money (and weight) is best spent elsewhere.
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HampusSoder
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Re: Aero improvements

Post by HampusSoder » Sat Sep 26, 2015 9:07 am

adrianm wrote:Personally I think all the splitters, holes and spoilers make a tiny if any difference and in some cases could actually slow the car down.

They just don't go fast enough to need all the fancy aero bits.

If you've got the best suspension, best tyres etc then it might be worth the effort but IMHO the money (and weight) is best spent elsewhere.
I'm fairly sure you're correct on the big spoilers, I think the Evo wing may be a bit too much and let's say on a race track would higher the overall lap time (atleast with stock power). Altho I would personally think that splitter works quite good and doesn't really weigh that much.
Image
(cred to Sjoerd for the pic)

The holes in the bumper is a big questionmark for me. Not sure if it will just upset the rear or effectively reduce the drag.

I know these aero improvements is only noticed at high speed and only marginable, I sill think it's fun to try to improve (even if it's marginable).
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trublustu
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Re: Aero improvements

Post by trublustu » Sat Sep 26, 2015 1:01 pm

Aero mods are often more show than go.
I have seen some huge diffusers, canards in the wrong place and `evo` style spoilers which would just sap power on any straight.

Not that there are not improvements to be made.
I have a track car which gets regular outings with different mods.

A splitter is a great addition.
Not only does it help to eliminate understeer (front downforce) it also keeps the rest of the car more settled through fast corners (vacuum effect)
I have had a `Richard Mansfield 2` fiberglass version which looked brilliant and worked well (I shattered it coming off track at Rockingham)

4894

I have since replaced it with a plywood clone which does the job perfectly

5349

as for the back end.
The Puma handles great out of the box and the bootlid does the job of keeping things under control.
Most wings and spoilers are just styling extras. giving more drag than anything else
In order to help out with aero I have fitted a subtle lip spoiler

5128

As for the holes in the back bumper.
If you remove the spare wheel you are left with a huge `air dam` under the back end.

5438

the holes just relieve the high pressure air. another (tidier) option is to keep the spare wheel! or just box off the void it leaves with lightweight alloy sheet.


I am no Aero expert but have tried a few things and this is what I`ve learnt.
I will be experimenting with more aero, but keeping it subtle as our cars are not exactly overpowered and increasing drag is a bad idea.
I hope this is helpful and gives you some inspiration.

There is more info in my build thread
https://www.projectpuma.com/viewtopic.php?f=64&t=26160" onclick="window.open(this.href);return false;
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HampusSoder
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Re: Aero improvements

Post by HampusSoder » Sun Sep 27, 2015 10:02 am

trublustu wrote:Aero mods are often more show than go.
I have seen some huge diffusers, canards in the wrong place and `evo` style spoilers which would just sap power on any straight.

Not that there are not improvements to be made.
I have a track car which gets regular outings with different mods.

A splitter is a great addition.
Not only does it help to eliminate understeer (front downforce) it also keeps the rest of the car more settled through fast corners (vacuum effect)
I have had a `Richard Mansfield 2` fiberglass version which looked brilliant and worked well (I shattered it coming off track at Rockingham)

4894

I have since replaced it with a plywood clone which does the job perfectly

5349

as for the back end.
The Puma handles great out of the box and the bootlid does the job of keeping things under control.
Most wings and spoilers are just styling extras. giving more drag than anything else
In order to help out with aero I have fitted a subtle lip spoiler

5128

As for the holes in the back bumper.
If you remove the spare wheel you are left with a huge `air dam` under the back end.

5438

the holes just relieve the high pressure air. another (tidier) option is to keep the spare wheel! or just box off the void it leaves with lightweight alloy sheet.


I am no Aero expert but have tried a few things and this is what I`ve learnt.
I will be experimenting with more aero, but keeping it subtle as our cars are not exactly overpowered and increasing drag is a bad idea.
I hope this is helpful and gives you some inspiration.

There is more info in my build thread
https://www.projectpuma.com/viewtopic.php?f=64&t=26160" onclick="window.open(this.href);return false;
Thanks for the answer, I actually got my splitter from Richard Mansfield aswell!

I've actually been thinking about getting a gurney flap aswell as I agree with you on the big wings. Not sure the flap really makes a difference, but it's cheap and looks are ok, so not a reason for not adding it! :) Where did you get your from?

Also, do you mean the holes in the bumper are made for realising the high pressure ahead of the rear bumper (where the spare wheel go)? That makes sence, I thought they were to reduce the drag behind the car.
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Flatoutfarr
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Re: Aero improvements

Post by Flatoutfarr » Sun Oct 11, 2015 4:25 pm

Having raced various cars from single seaters to saloons for nearly 40 years, aero works on some and not the others. It's easy to get single seaters benefiting from aero devices. Saloons are an other matter. If you don't have a flat bottom and have the car running really low, don't waste your time and money. Fancy big wings on the boot will slow you down.

You will go faster if you have decent brakes and suspension and go to race school or get private lessons from someone like Rob Wilson. I did race school at Brands in 1975. Well worth the money.
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