Coweling and engine bay aero
- Thread starter The Convert
- Start date
Honestly the issue is that the M3 cowl doesn't seal with our hoods. Need to look into if it'll seal with a powerdomed E82 hood. Probably not since it's made to fit the E9x dimensions.
Hence why I'm still without a cowl. No point until I figure out the seal IMO.
Just an observation about comparing OE stuff to race team stuff. Do keep in mind that an OE budget and man hours put in are probably well above that of any race team. So when you post a race car picture, 'see this works' may only apply to a single season or even a single event. The race team may have collected data and found it to not work and changed. Or they may have changed to what is pictured. We have no way to know without first hand info.
Everyones foot won't fit the same shoe. It's best you take your own course and collect your own data. Simple free removal or parts, test and addition of parts, test is quite simple.
I'd also like to point out that we have a temp probe built into the cars we can put wherever to log changes in that regard. Just move your Ambient Temp Sensor where you wish and log it.
Everyones foot won't fit the same shoe. It's best you take your own course and collect your own data. Simple free removal or parts, test and addition of parts, test is quite simple.
I'd also like to point out that we have a temp probe built into the cars we can put wherever to log changes in that regard. Just move your Ambient Temp Sensor where you wish and log it.
According to BMW the tray only serves the purposes of sealing the engine bay to provide fresh air to
the cabin,, keeping water, debris away from the engine bay.
Removing this tray allows fresh air to the engine bay thus turning the bonnet into a hood scoop and
allowing the engine bay to be pressurised at speed which has its pros and cons, its up to the individual race
team to work out the benefits and shortfalls of each modification.
There is no shortfall modifying the cowl properly on the street but removing it can have some major issues.
The cowl was designed for stock power along side the rest of the car, the cowl impedes air flow and only
causes issues when running 2 to 3x the factory hp output sub 150mph.
Lets be brutally truthful our cars aren't supercars and aerodynamics was second on the agenda, you want
aero buy a lambo, ferrari or what ever supercar you fancy.
When was the last time you saw a supercar that that hasn't got a mid mounted engine in the last 20 years.
the cabin,, keeping water, debris away from the engine bay.
Removing this tray allows fresh air to the engine bay thus turning the bonnet into a hood scoop and
allowing the engine bay to be pressurised at speed which has its pros and cons, its up to the individual race
team to work out the benefits and shortfalls of each modification.
There is no shortfall modifying the cowl properly on the street but removing it can have some major issues.
The cowl was designed for stock power along side the rest of the car, the cowl impedes air flow and only
causes issues when running 2 to 3x the factory hp output sub 150mph.
Lets be brutally truthful our cars aren't supercars and aerodynamics was second on the agenda, you want
aero buy a lambo, ferrari or what ever supercar you fancy.
When was the last time you saw a supercar that that hasn't got a mid mounted engine in the last 20 years.
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I agree. Few of the cars that was posted with no windshield cowl/sealing, i would guess the reasons are(but not limit to) 1: have huge hood vents which most likely are more than enough to vent out the under hood pressure/heat
2: car is purpose build for a more low speed track that aero is not where they want to invest/focus into, especially you can see few of cars are more focused on body/suspensions reinforcement which would cause clearance issue for reusing stock cowl.
3: maybe those cars are the losing teams?
just because it a race car, doesnt mean it was build perfect.Also, the Berk technologies time attack car, it has a sealing lip that is installed on the hood side.
And like i said b4. I personally tested out sealed or non sealed at base of windshield for extracting heat not aero purpose. It for sure help with letting heat out at lower speed with no seal. But at the end, after a lot of research. i feel sealing it up have more pros than cons rather the pros are performance benefits or not. I also end up adding hood vents to help heat extraction which helped a ton.
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Just found this. Right from an aerodynamic engineer. This should end the argument of sealing the hood will affect aero or not.
Under the "downforce: traction from air" section
"Sealing the hood seams can also increase front downforce, as this prevents the pressure in the engine bay from leaking to the topside of the car. (In some cases, however, the leakage of the underhood pressure can be used to reduce the front downforce and help move the balance rearward.)"
Yes this was stated earlier in the thread but that does not take into account the undertray which prevents lift and adds to downforce of the car.
In our case it will add drag and maybe some lift at 150mph + but the cooling effect of the open under hood area will have far greater benefits for a street car
pushing 3x the factory hp.
There is an easy way to test it but not cheap is to put weight sensors between the strut tower and shock or scales under the wheels in a wind tunnel and see how much extra weight gain or loss is achieved using a cowl or not or a modified one.
I don't have access to one but there are so many experts on here maybe they can lend a hand.
pushing 3x the factory hp.
There is an easy way to test it but not cheap is to put weight sensors between the strut tower and shock or scales under the wheels in a wind tunnel and see how much extra weight gain or loss is achieved using a cowl or not or a modified one.
I don't have access to one but there are so many experts on here maybe they can lend a hand.
Someone with access to a wind tunnel would be awesome. Would be interesting to know what the time would cost someone too. If we came up with enough things to test, could be a good crowd funding project...
Just remember the roof wont move if the ambient temperature goes too low, and the cooling system will freak out if too high.
Rather than downforce or drag, I'd be more interested to know if having or removing the cowl affects actual engine bay air flow and mean temps in the bay.
With the cowl removed does the in flowing air (from the front of the windshield) slow engine bay air flow or lead to stagnant hot zones?
Does the cowl installed trap more heat when slow or stationary but lead to a better flow of heat out while moving at medium and high speeds?
i.e.
With the cowl removed does the in flowing air (from the front of the windshield) slow engine bay air flow or lead to stagnant hot zones?
Does the cowl installed trap more heat when slow or stationary but lead to a better flow of heat out while moving at medium and high speeds?
i.e.
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That's amazing. Seriously in need of vents on top of the bonnet behind the radiator.
I'm sure the bonnet was properly latched at the front.
At least the FMIC and radiators will be getting a great flow of air for cooling!
There is no airflow exit path under the front of the car it will flow directly into the trans tunnel on a stock car sucking out the hot air, this is where
an FF manifold will help tremendously and also help keep the manifold runners, plenum, head and block run cooler.
If you have relocated inlets this will greatly increase airflow around the engine and help with cooling even more.
Its easy to extract power out of these engines but cooling was an after thought.
an FF manifold will help tremendously and also help keep the manifold runners, plenum, head and block run cooler.
If you have relocated inlets this will greatly increase airflow around the engine and help with cooling even more.
Its easy to extract power out of these engines but cooling was an after thought.
The air will escape where the exhaust and down pipes meet which is completely unsealed and has low pressure, fast flowing air sucking it out.
There's also gaps in the left wheel well. You can see the road if you look down there.
The 335 has trays but these have gaps any high pressure air will flow out of.
Plus the rear underside of the car looks like a turbulent nightmare.
Air travels a path of least resistance, yes some might escape through there but majority will go through the tunnel cooling the gearbox.
Don't forget our manual boxes don't have active gearbox oil cooling unlike the e92 m3 where the BMW engineers decided it was a good idea.
Having more air going through the tunnel is not such a bad idea.
So many pros to this mod vs 1 possible unproven con and by reading a lot of material if it does it will only be a problem at over 150mph but that's if you only run with no undettray.
The only way to prove this is test it in a wind tunnel which won't happen any time soon.
Don't forget our manual boxes don't have active gearbox oil cooling unlike the e92 m3 where the BMW engineers decided it was a good idea.
Having more air going through the tunnel is not such a bad idea.
So many pros to this mod vs 1 possible unproven con and by reading a lot of material if it does it will only be a problem at over 150mph but that's if you only run with no undettray.
The only way to prove this is test it in a wind tunnel which won't happen any time soon.
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