E90Post
 


Extreme Powerhouse
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Tracking, Autocrossing, Dragstrip, Driving Techniques > Non-M Aerodynamics



Reply
 
Thread Tools Search this Thread
      04-20-2021, 10:26 PM   #1
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
Non-M Aerodynamics

I was looking online and found this diagram, which lead me to look for aerodynamic parts for the e92 besides going full race car mode. Does anyone know of aero parts you could put on the e92 non-m to improve the aerodynamics? Also, how much will they improve the cars aerodynamics?
Attached Images
 
Appreciate 0
      04-21-2021, 09:32 AM   #2
tcphoto
Brigadier General
tcphoto's Avatar
United_States
3477
Rep
3,020
Posts

Drives: E92 335i 6MT Coupe
Join Date: Dec 2009
Location: Nashville, TN

iTrader: (1)

It looks like the difference starts around the windshield and gets worse at the shark fin. It doesn't state if the M3 is a slick top but I would guess so and the 335 most likely has a sunroof and no trunk lip. The PO added an Aero lip, rear window and trunk lip on mine. I almost immediately pulled the rear items off and replaced them with a carbon fiber lip on the trunk.
__________________
Appreciate 0
      05-18-2021, 02:13 AM   #3
streetpro
Second Lieutenant
streetpro's Avatar
Czech_Republic
87
Rep
236
Posts

Drives: e92 335iA
Join Date: Nov 2018
Location: Prague

iTrader: (0)

Garage List
You have to define what to improve...
if Cd (coefficient of drag, basically how smoothly the car goes through the air) then take a closer look as basic shape has better Cd then M3 (and it makes perfect sense as M is optimized for performance, not consumption).
If more downforce is asked, it comes with a price tag of higher drag and additional spoilers/wings...
and yes, the basic shape has light front at high speeds (over 180 kmh let say), anyone on autobahn has experienced this phenomena when chasing a P911T I guess :-)
Vented hood improves the matters a bit, at least for me it has worked fine (the vents/louvers must be in the front section of the hood, where the low pressure area is, not at the rear where is the M3 intake opening and people have feelings that it ventilates the engine - in reality it does the opposite).
__________________
"If everything seems under control, you're not going fast enough.” Mario Andretti
Appreciate 0
      09-01-2021, 01:18 PM   #4
Thumbie
Second Lieutenant
Thumbie's Avatar
81
Rep
220
Posts

Drives: 2011 M3/4/6
Join Date: Sep 2021
Location: SF Bay Area

iTrader: (0)

That is a cool comparison.

So from what I am gathering, and assuming you are talking about downforce per streetpro's comment, adding a little downforce to the front would be my first step.

I personally am considering swapping to M3 front bumper or adding a like a lip/dam. Next would be rear spoiler or, and I haven't done research yet, cutting up the rear bumper to relieve pressure buildup (this is common on miatas).

From there you could get into more advanced things like vents in the fender and brake ducting, etc.

Last edited by Thumbie; 09-01-2021 at 01:18 PM.. Reason: spelling
Appreciate 0
      09-01-2021, 06:48 PM   #5
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
Quote:
Originally Posted by streetpro View Post
You have to define what to improve...
if Cd (coefficient of drag, basically how smoothly the car goes through the air) then take a closer look as basic shape has better Cd then M3 (and it makes perfect sense as M is optimized for performance, not consumption).
If more downforce is asked, it comes with a price tag of higher drag and additional spoilers/wings...
and yes, the basic shape has light front at high speeds (over 180 kmh let say), anyone on autobahn has experienced this phenomena when chasing a P911T I guess :-)
Vented hood improves the matters a bit, at least for me it has worked fine (the vents/louvers must be in the front section of the hood, where the low pressure area is, not at the rear where is the M3 intake opening and people have feelings that it ventilates the engine - in reality it does the opposite).
I know with the m3 they have a front vent on the belly pan. Could something like that help or not really?
Appreciate 0
      09-01-2021, 06:51 PM   #6
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
Quote:
Originally Posted by Thumbie View Post
That is a cool comparison.

So from what I am gathering, and assuming you are talking about downforce per streetpro's comment, adding a little downforce to the front would be my first step.

I personally am considering swapping to M3 front bumper or adding a like a lip/dam. Next would be rear spoiler or, and I haven't done research yet, cutting up the rear bumper to relieve pressure buildup (this is common on miatas).

From there you could get into more advanced things like vents in the fender and brake ducting, etc.
With aero on the car would the aerodynamic kit work from bmw? I can see the front lip doing something but the rear diffuser and the spoiler I am not sure about.
Appreciate 0
      09-07-2021, 12:23 PM   #7
Thumbie
Second Lieutenant
Thumbie's Avatar
81
Rep
220
Posts

Drives: 2011 M3/4/6
Join Date: Sep 2021
Location: SF Bay Area

iTrader: (0)

Quote:
Originally Posted by tylerhart_21 View Post
With aero on the car would the aerodynamic kit work from bmw? I can see the front lip doing something but the rear diffuser and the spoiler I am not sure about.
Depends on if they were designed for "style" or function. I am not familiar with bmw's aero kit. If it is BMW brand I assume there is some function there. For example the M3 rear bumper has built in diffuser. that vent above the exhaust tips does serve some function.

Overall the key is a balanced setup, obviously. Adding a massive spoiler to a non-M will give you too much rear downforce, you would also need front air dam or something to balance it out.

Depends on what the goals are for the car.
__________________
-Thumbie

2011 Jerez E90 M3 6-speed Competition Package
Appreciate 0
      09-13-2021, 09:07 AM   #8
streetpro
Second Lieutenant
streetpro's Avatar
Czech_Republic
87
Rep
236
Posts

Drives: e92 335iA
Join Date: Nov 2018
Location: Prague

iTrader: (0)

Garage List
Again, it depends on the definition of a massive spoiler. Because the rear wing on the trunk lid may reduce lift, it is rarely able to generate significant downforce because it is in the area of the swirled air. That's why DTM/GT cars have wings on high struts to get them into a "clean" airflow.
A splitter on the front will definitely help, both to increase downforce and to reduce drag (under certain conditions).
The lower openings in the front part of the engine cover allows a much higher flow through the radiator (the pressure difference between the part in front of the car, where the air is in positive pressure, while behind the radiator, through which it is slowed down and is further sucked under the car by faster moving air/low pressure zone - Venturi effect).
That's why M cars put transmission coolers etc in there, which would otherwise have to be in front of the water/air cooler.
__________________
"If everything seems under control, you're not going fast enough.” Mario Andretti
Appreciate 0
      09-13-2021, 03:38 PM   #9
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
Quote:
Originally Posted by streetpro View Post
Again, it depends on the definition of a massive spoiler. Because the rear wing on the trunk lid may reduce lift, it is rarely able to generate significant downforce because it is in the area of the swirled air. That's why DTM/GT cars have wings on high struts to get them into a "clean" airflow.
A splitter on the front will definitely help, both to increase downforce and to reduce drag (under certain conditions).
The lower openings in the front part of the engine cover allows a much higher flow through the radiator (the pressure difference between the part in front of the car, where the air is in positive pressure, while behind the radiator, through which it is slowed down and is further sucked under the car by faster moving air/low pressure zone - Venturi effect).
That's why M cars put transmission coolers etc in there, which would otherwise have to be in front of the water/air cooler.
So in short if you get a gt style wing it will be able to generate downforce, while a spoiler may reduce lift. The front splitter would help, when it comes to certain situations. Now with the vent on the engine cover, it helps with air flow thought the radiator etc. Correct me if I am wrong but would that help the radiator become more efficient or make it able to take in more air? So lowering oil temps?
Appreciate 0
      07-12-2023, 05:11 PM   #10
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
After looking at the 918 Cayman gt4 MR, I have seen the underbody aero. Manthey racing and Porsche will sell you the aero parts but it’s 250 dollars. What does the underbody aero do?

According to Manthey:
  1. Guide air out from underneath the car
  2. Avoid to get air in from the side of the car
The first point is probably clear, the second one means that by creating a “air curtain” underneath the side skirt will avoid “dirty” air to get under the car from outside.

The aero could be more complex with getting the angles and the placement as well. However I have made a prototype with paper and duct tape and have someone that is measuring the MR fins to get the length close. I will keep y’all posted, but if y’all have any comments to add or suggestions let me know.

The aero on a gt4 soon below:
Attached Images
   
Appreciate 0
      07-17-2023, 06:45 PM   #11
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
After some testing, the rs aero is not the most practical thing right now. I have made a some prototype based of the gt4 aero. The goals is block off the diviet behind the wheel and push the air to the side skirt. If anyone knows more about this topic let me know. I have attached the prototype and the small divet.
Attached Images
  
Appreciate 1
Thumbie81.00
      10-01-2023, 04:20 PM   #12
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
Does anyone know how much the front air dam from BMW (aerodynamikpaket) reduces the lift in the front? The Alpina b3 front air dam dropped the lift by 30kg. But I'm not sure about the Aerodynamikpaket air dam since it is a different design.
Appreciate 0
      01-18-2024, 06:19 AM   #13
streetpro
Second Lieutenant
streetpro's Avatar
Czech_Republic
87
Rep
236
Posts

Drives: e92 335iA
Join Date: Nov 2018
Location: Prague

iTrader: (0)

Garage List
The airdam and splitter will reduce the pressure under the front of the car the most (the airdam blocks the excess airflow under the car, and the splitter adds a force vector that acts from above - for simplicity we can call it front bumper overpressure). I dont have any exact numbers for BMW e9x aerodynamikpaket but it is not as deep as Alpina and mimics more the splitter, so similar or lower number would be my guess.
Everything I'm describing only results in a reduction of lift in the vast majority of cases, and at speeds above 150 km/h. If we're talking 70-120, where cars normally move around technical parts of the circuit, the gain is virtually minimal.
That GT4 kit was developed on a specific model according to the tunnel flow, moreover lower compared to the production e90, so the idea to implement on our platform is good, but the benefit will not be great.
For it to work, the e9x would have to be lowered, with a smooth floor, some form of side screens/stoppers and a functional rear diffuser (this needs to have a large area, small angle and smooth transition, which is hard to achieve on a production model).
__________________
"If everything seems under control, you're not going fast enough.” Mario Andretti
Appreciate 1
      01-18-2024, 07:20 PM   #14
rismo
Captain
75
Rep
910
Posts

Drives: BMW E92 335
Join Date: Jul 2008
Location: Europe

iTrader: (0)

Felix did some great research:

https://www.1addicts.com/forums/show....php?t=2062194
__________________
BMW 335 E92 09 - Full options - DKG - MHD by Buraq - RB Next Gen - RB Inlets/Outlet - Forge Diverter Valves - AR Catless DP - Afe Intake - Helix IC - FuelIT Stage 2 LPFP - Ar Oil Cooler - PPK Water Cooler - M3 Suspension - JRZ RS1 Shocks - Eibach Pro Springs - Drexler LSD - BMW IS Exhaust - Carbon Endurance Brake Pads - Stainless Steel Brake Lines - M101 Wheels - Michelin PS2 - M-Tech Body - M-Strutbar
BMW M550i G30 2019 - BM3
Appreciate 1
      01-23-2024, 12:35 PM   #15
tylerhart_21
Private First Class
tylerhart_21's Avatar
United_States
33
Rep
181
Posts

Drives: 2008 Bmw 328i Coupe
Join Date: Feb 2020
Location: North Carolina

iTrader: (0)

Garage List
2008 Bmw 328i  [0.00]
After reading the thread, from my understanding it’s not necessary to do all the aero bits on a normal street car. But at higher speeds having more rear downforce will help with stability but too much creates drag. I haven’t looked into the videos or got one of the books, but Newman prefers having a balance (between front and back) and having the lift close to 0 or 0. With all that said having the underbody aero seems to be more helpful with the hope of keeping the look while having less lift and hopefully reducing the possibility of drag. Looking at Porsche it seems that they use some hidden aero bits on the gt cars. I have been looking to see if I could recreate the same diffuser below (from 991.1 gt3). The problem I see is the muffler and placement as noted above, to makes a smooth transition. I thought about using a Tesla model X undertray for the rear diffuser since it’s cheaper than the gt3 one. I added some photos I took of the Garage 42 racecar and it’s aero if anyone is curious.
Attached Images
    
Appreciate 0
      01-23-2024, 06:22 PM   #16
rismo
Captain
75
Rep
910
Posts

Drives: BMW E92 335
Join Date: Jul 2008
Location: Europe

iTrader: (0)

Honest response:

I live near Germany and pushed the car many times beyond 300km/h.
On M-sport suspension with factory alignment and default e92 parts this was pretty stable.
When I made the car stiffer the car started to bounce above 240-250, however adding the JRZ suspension the car is now a stable.

Long story short, for stability etc the suspension on our cars is much more relevant / will have more impact.
On the other hand, I always support science and engineering projects ;-)
__________________
BMW 335 E92 09 - Full options - DKG - MHD by Buraq - RB Next Gen - RB Inlets/Outlet - Forge Diverter Valves - AR Catless DP - Afe Intake - Helix IC - FuelIT Stage 2 LPFP - Ar Oil Cooler - PPK Water Cooler - M3 Suspension - JRZ RS1 Shocks - Eibach Pro Springs - Drexler LSD - BMW IS Exhaust - Carbon Endurance Brake Pads - Stainless Steel Brake Lines - M101 Wheels - Michelin PS2 - M-Tech Body - M-Strutbar
BMW M550i G30 2019 - BM3
Appreciate 1
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 11:00 AM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST