Handling and aerodynamics

Don't think aerodynamics has got much to do with road car handling except at very high speeds? You're wrong! (And if you run any kind of car on the track, and you're not using good aero, you're crazy!) Buy the book now at www.amazon.com/dp/B0D7327WSB or Amazon in your country.

[@johhnnn]

just drove across the state last weekend. straightline stability was absolutely brutal on some of those long straights with crosswinds. glad this video showed up, i was thinking it was all alignment related.

[@skippy2987]

Also on aerodynamics, I've used principles I learned from you take a couple of cars from "overheating mess that wouldn't even cool decently in a 50km/h cruise" to "sometimes the fan comes on at the lights, and it cools down fast with pretty much any constant forward motion". Using a Dwyer Magnehelic Differential Pressure Gauge and about $10 in materials. I have a digital manometer now, so my DMDPG (ha! Callback acronym) sits in my Glass Cabinet of Cool Stuff.

[@TheJcman72]

I think that the best way to convince people about aerodynamics is to put them on a bike behind a truck and then deviate outside of its aerodynamic "shadow". I managed to go up in a road just being sucked by the truck. And the fun thing is that we can manage to find that sweet spot where you feel that suction. That's nice to go up a hill at around 60 km/h without even using the pedals!

[@JustinBone]

Your videos are pretty informative; I’m not a big “book person,” but I definitely plan to buy them. I’m modifying a 2012 Audi TT (RS,) and it came with the factory adaptive spoiler. I have to say for all the flack the original, prior generation TT received, the second generation feels quite stable even at higher speeds. I viewed some videos from Audi regarding the airflow of the vehicle and it seems that their adaptive spoiler works well at increasing pressure at the back for higher speed stability. I plan to put a mild widebody on the car that is basically just 30mm wider up front, 35mm wider in the rear. The fronts have a slit behind the wheel as air/pressure release. After watching your tufting video as well, I plan to do a before and after to see how the airflow changes. I’m expecting more turbulent airflow from the wheels as the lower half of the tire will be slightly more exposed. Hoping some good underbody work will help keep it glued to the ground.

[@DBatty]

I remember reading your tech articles in car magazines in the 90s. Autospeed? Zoom? Will definitely buy a copy of this as I have a track MX5 to tinker with.

[@JulianEdgar]

I've written a lot since then! www.amazon.com.au/stores/Julian-Edgar/author/B00C3MRYN4/allbooks?ref=ap_rdr&isDramIntegrated=true&shoppingPortalEnabled=true

[@Remenschneider]

Great video! It's important to think about the relation of lateral center of pressure to center of mass, too. Edit: Just noticed you already covered that in the "Aerodynamic downforce balance" video Seeing the rear quarters of your Insight: Do those separation edges work on my car as well (Gen 8 Civic Hatchback), or do they only work on coupe shapes? Is there a good rule of thumb up to which z-height they reduce drag, or is it always good to extend them up until the rear end of the roofline, to form something resembling a "rectangle of separation edges"?

[@JulianEdgar]

Yes, rectangle of separation edges.

[@MichaelFitzpatrickk]

Does your new book cover fender louvers? By happenstance I have upper rear fender louvers on an e30 that came with the car when I bought it (PO must have tried to emulate the z3 fenders). They are legitimate and not fake but I wasn't sure if that was helping or hindering the aerodynamics of the car.

[@JulianEdgar]

No, it shows how *you* can measure and assess the effectiveness of any aero modifications - including fender louvres. Much better than rules of thumb or guesswork, that are usually wrong.

[@MichaelFitzpatrickk]

@@JulianEdgar Thank you. I'm looking forward to reading it.

[@JulianEdgar]

Actually, that's in the book that's already published - www.amazon.com/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8 or Amazon in your country. The suspension book has only a brief coverage of aero.

[@cdw3423]

My 94 Ford Ranger would normally under steer, but if I was accelerating hard from a stop or slow speed through a corner it would sometimes over steer. I'm guessing that is just a matter of loosing traction because of the hard acceleration. The odd part was at high speeds (60+mph) I could get 4 wheel drift. Is it possible I was getting enough aerodynamic lift on the front wheels to cause that?

[@JulianEdgar]

Could be lots of reasons eg aero, or simply the fact that the torque at the tires is a lot less at 60 mph than at 20 mph.

[@tim0339]

What would be your top 3 things to do to a truck to increase its aerodynamics

[@JulianEdgar]

kzbin.info/www/bejne/p6e0koaapdp6ebM

[@tim0339]

@@JulianEdgar oh wow you already have a video on this that’s great thank you.

[@ohitstarik]

How did you measure live downforce on the insight?

[@JulianEdgar]

Suspension height sensors.

[@RwP223]

Anyone seen string potentiometers used to measure suspension travel / ride height at the corners? As an alternative to linear transducers...

[@JulianEdgar]

Production car suspension height sensors are easiest and cheapest.

[@frederickcook87]

👌🏾❤️👌🏾

[@chooky5684]

Which book covers 4wd vehicles mate ?

[@JulianEdgar]

Off road 4WD? I don’t cover that specifically, except for some special systems like active swaybars. However, exactly the same ideas apply so the book shown in this video will be very helpful.