I'm uploading a video of my little Civic at Spa Francorchamps next week. You will be able to see I can take corners at 180kmh with a shocking ease ! And I believe its due to my full under panel and proper diffuser. I can't see how my car can feel this safe at those speeds otherwise. I also have a near 0° angle spoiler to help the diffuser. You can see it at the end of my last Short, I'm in Eau Rouge at 180kmh not lifting pedal to the metal :| So yes, the first aero mod I've made was UNDER the car !
How did you go about designing the underbody trays? Do you have access to any high end equipment (3d scanners, printers, etc.) or did you go a different route?
Equipment? For development, all you need is cardboard, tape and a way of measuring aero pressures - cheap and easy. Covered in my book - www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
@@JulianEdgar I'm aware that simple materials will suffice for the design process. I was just curious as to how the initial poster of the comment went about his design process and some of his thoughts. Your book looks quite thorough otherwise.
Imagine one project of Alfa Romeo and Mazda. Italian beauty and Mazda mechanics... ohhhh what, that actually happened... but Italian engine and Mazda rust... I mean, Mazda body. That was a very bad relationship 😅
I have a much better idea: imagine when a car is designed without cost being an obstruction. Many good inventions are killed because mainstream buyers won't give a f about how a car drives as long as it drives and is the right shape&colour for them.
That last point is something a lot of people overlook. When you add downforce to one end of the car, it causes lift on the other end. So for example, a front splitter and rear spoiler need to be properly balanced, or you get weird handling effects at speed.
I agree about the effect of downforce vs lift on handling. My direct experience is with motorcycles, where fairing and windscreen choice together can make the difference between a settled and unsettled suspension dynamic, most notably cresting a rise with a headwind.
I think I would appreciate more discussion of sidewind aerodynamics with regard to suspension and handling. I may have missed that discussion so far. Anyway I know it’s difficult to discuss, but there are historical streamlined designed that had poor crosswind handling so it must still be worth raising if a modification could actually effect sidewind sensitivity.
Side wind stability is covered in detail in my book: www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
Thank you - but to be honest, it's just a very superficial overview suitable for an 8 minute YT video. The proper information isn't free - but it's vastly better than the video, too. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
I do think there’s one other sort of exception to your remarks about efficiency effects on mileage, like trucks, in that electric vehicles have far fewer efficiency losses over their RPM curve or load demand, so changes in drag have a much more direct effect on mileage. (Yes the other factors are rolling resistance and parasitic/constant loads).
Hey Julian. I am about to purchase your aero and suspension books. I have always been dreaming about a flat underbody modification you suggested in your older videos. The biggest thing that has been holding me back is that flipping le mans Mercedes and that GTR at Nurbugring accident. They both have flat underbody. I am scared that it will happen to me when I go at 250kmh++
Time for me to get smarter, so I've just ordered "Vehicle Ride and Handling" + "Vehicle Aerodynamics". Seems like my E46 will become a big playground :D
@@JulianEdgar Oh, certainly! I'm hungry for knowledge and want to improve my rusty mechanical skills. I'm sure I'll read them twice and start fiddling with the car on my own. I have a plan to try, test and implement as many modifications as possible. Already thinking about somewhat scientific and deterministic methodology for validating the pros and cons of each modification. Writing a checklist to follow before starting any experiment, as collecting reliable data will be a heap of work. Aiming for the same conditions as temperature, location, wind, tire degradation, same surface, fuel level, quality logging tools, making sure A/C, lights, car audio is always off and many more. Baseline aka car must be in top condition and that's what I'm working on currently. I'll most likely invest in: - 2 new sets of wheels and tires (performance and eco oriented) that will be mounted only for testing, - calibrated manometers, - action cameras, - laser distance logger, - SPL meter, - Racelogic VBOX Touch v3 for lateral acceleration, 100-200, braking performance etc. - Scales for weighing cars, modifications, corner balancing. - Workshop improvements and new tools. - Etc. And then research all the way! I'm really motivated to check the individual and collective modifications results! I'm hoping the Dunning-Kruger effect won't hit me too hard either. Once I obtain enough skills and know-how, I'll start with my own track build.
Thank you - I am sure you would enjoy the book. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
I’m currently creating a rally/safari inspired modified car (Ford Fiesta). As a rally car it will be slightly raised to deal with gravel and bumps etc but this will also create more lift correct? I’ve got front and rear undertrays for protection and aerodynamics, including a rear diffuser. My question is about suspension set up, if the rear is slightly higher than the front, will this decrease lift or is it better to keep both ends at the same level? Thanks for all your videos, they’ve been very informative:)
Without aero pressure testing it's all guesswork. I don't like guesswork when proper development is so easy. If you're trying to do it from my videos you're almost certain doomed to sub-optimal results - the videos are deliberately quite superficial. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
The one thing i dont understand about downforce is people will say they get about 75 lbs of downforce from aero mods and thats considered quite good. But in a 3000 lb car how does that make any noticable difference? And why not just put 100 lbs of weight in the back of the car to get that all the time?
Covered in detail in my book, but basically two points - downforce has no inertia, and downforce has a disproportionate effect on vehicle handling, probably through interactions with the natural frequency of the suspension. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
@@JulianEdgar I figured the inertia was the main point. Downforce is basically free grip, whereas adding weights costs acceleration, both linear and centripetal.
I'm uploading a video of my little Civic at Spa Francorchamps next week. You will be able to see I can take corners at 180kmh with a shocking ease ! And I believe its due to my full under panel and proper diffuser. I can't see how my car can feel this safe at those speeds otherwise. I also have a near 0° angle spoiler to help the diffuser. You can see it at the end of my last Short, I'm in Eau Rouge at 180kmh not lifting pedal to the metal :| So yes, the first aero mod I've made was UNDER the car !
Sounds great!
How did you go about designing the underbody trays? Do you have access to any high end equipment (3d scanners, printers, etc.) or did you go a different route?
Equipment? For development, all you need is cardboard, tape and a way of measuring aero pressures - cheap and easy. Covered in my book - www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
@@chaseharrison2064 none of that, only stuff you can find in your DIY store
@@JulianEdgar I'm aware that simple materials will suffice for the design process. I was just curious as to how the initial poster of the comment went about his design process and some of his thoughts.
Your book looks quite thorough otherwise.
Imagine what could’ve been achieved in Citroën, SAAB, and Lancia had merged together in the 70’s and compiled their ideas and innovations together.
Instead of three unique brands we’d have lost at least two as early as the 70s.
Imagine one project of Alfa Romeo and Mazda. Italian beauty and Mazda mechanics... ohhhh what, that actually happened... but Italian engine and Mazda rust... I mean, Mazda body.
That was a very bad relationship 😅
I have a much better idea: imagine when a car is designed without cost being an obstruction.
Many good inventions are killed because mainstream buyers won't give a f about how a car drives as long as it drives and is the right shape&colour for them.
Most unreliable car ever built any% speedrun
That last point is something a lot of people overlook. When you add downforce to one end of the car, it causes lift on the other end. So for example, a front splitter and rear spoiler need to be properly balanced, or you get weird handling effects at speed.
Can highly recommend this book, full of fantastic info and very well presented. Great work Julian as always
Thank you. Don't forget to leave a detailed Amazon review - it's one of the few ways a self-published author can promote their work.
I agree about the effect of downforce vs lift on handling. My direct experience is with motorcycles, where fairing and windscreen choice together can make the difference between a settled and unsettled suspension dynamic, most notably cresting a rise with a headwind.
I think I would appreciate more discussion of sidewind aerodynamics with regard to suspension and handling. I may have missed that discussion so far. Anyway I know it’s difficult to discuss, but there are historical streamlined designed that had poor crosswind handling so it must still be worth raising if a modification could actually effect sidewind sensitivity.
Side wind stability is covered in detail in my book: www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
Well, I guess that's perfect since I have a copy on hand! I'll work on that now.
Could you make a vidéo about hood vents, how it reduce drag, lift and engine bay temp
How is such knowledge free on the internet
Thank you - but to be honest, it's just a very superficial overview suitable for an 8 minute YT video. The proper information isn't free - but it's vastly better than the video, too. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
Hi Julian, this book is currently listed as unavailable on Amazon in the United States. Any idea what's going on? Thanks!
I am chasing it up with Amazon. No reason from my end.
It's available again.
I do think there’s one other sort of exception to your remarks about efficiency effects on mileage, like trucks, in that electric vehicles have far fewer efficiency losses over their RPM curve or load demand, so changes in drag have a much more direct effect on mileage. (Yes the other factors are rolling resistance and parasitic/constant loads).
Hey Julian. I am about to purchase your aero and suspension books. I have always been dreaming about a flat underbody modification you suggested in your older videos. The biggest thing that has been holding me back is that flipping le mans Mercedes and that GTR at Nurbugring accident. They both have flat underbody. I am scared that it will happen to me when I go at 250kmh++
There is no likelihood of a car flying if you measure what you are doing as you make aero modifications.
@@JulianEdgar If I strictly study your book, I should be fine, right?
And do the described testing, yes.
Time for me to get smarter, so I've just ordered "Vehicle Ride and Handling" + "Vehicle Aerodynamics".
Seems like my E46 will become a big playground :D
Lots of reading there!
@@JulianEdgar
Oh, certainly! I'm hungry for knowledge and want to improve my rusty mechanical skills. I'm sure I'll read them twice and start fiddling with the car on my own.
I have a plan to try, test and implement as many modifications as possible. Already thinking about somewhat scientific and deterministic methodology for validating the pros and cons of each modification. Writing a checklist to follow before starting any experiment, as collecting reliable data will be a heap of work. Aiming for the same conditions as temperature, location, wind, tire degradation, same surface, fuel level, quality logging tools, making sure A/C, lights, car audio is always off and many more. Baseline aka car must be in top condition and that's what I'm working on currently.
I'll most likely invest in:
- 2 new sets of wheels and tires (performance and eco oriented) that will be mounted only for testing,
- calibrated manometers,
- action cameras,
- laser distance logger,
- SPL meter,
- Racelogic VBOX Touch v3 for lateral acceleration, 100-200, braking performance etc.
- Scales for weighing cars, modifications, corner balancing.
- Workshop improvements and new tools.
- Etc.
And then research all the way! I'm really motivated to check the individual and collective modifications results! I'm hoping the Dunning-Kruger effect won't hit me too hard either. Once I obtain enough skills and know-how, I'll start with my own track build.
Sounds good. Plenty of testing methodologies in the books.
Hands down the best video i've seen on this topic. Well done sir.
Thank you - I am sure you would enjoy the book. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
I’m currently creating a rally/safari inspired modified car (Ford Fiesta). As a rally car it will be slightly raised to deal with gravel and bumps etc but this will also create more lift correct? I’ve got front and rear undertrays for protection and aerodynamics, including a rear diffuser. My question is about suspension set up, if the rear is slightly higher than the front, will this decrease lift or is it better to keep both ends at the same level? Thanks for all your videos, they’ve been very informative:)
Without aero pressure testing it's all guesswork. I don't like guesswork when proper development is so easy. If you're trying to do it from my videos you're almost certain doomed to sub-optimal results - the videos are deliberately quite superficial. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
Re #5: will an extremely rough road reduce or disrupt the effectiveness of underbody downforce?
Not is the suspension is working properly.
@@JulianEdgar Good to know, thanks
I like aero for basically everything it can possibly do and to look cool and if all it does is look cool what's wrong with that
are you more interested in winning a fashion show or a race?
I like aero mods when they can't be seen, and that's often those who work the best !
Here's a crazy thought: Por que no los dos?
Aero isn't about looking good though, you are referring to styling and exterior design, not aero
@@mathewross3398 both
The one thing i dont understand about downforce is people will say they get about 75 lbs of downforce from aero mods and thats considered quite good. But in a 3000 lb car how does that make any noticable difference? And why not just put 100 lbs of weight in the back of the car to get that all the time?
Covered in detail in my book, but basically two points - downforce has no inertia, and downforce has a disproportionate effect on vehicle handling, probably through interactions with the natural frequency of the suspension. www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country.
@@JulianEdgar ok thank you!!!
@@JulianEdgar I figured the inertia was the main point. Downforce is basically free grip, whereas adding weights costs acceleration, both linear and centripetal.