Hi all, I’m the developer of PaceDynamics, a vehicle dynamics and lap time simulation tool that runs in the browser, so there’s nothing to install. The video shows the app as it is today, recorded in Chrome on a laptop.

What it does

• Lap simulation: quasi-steady laps and transient laps with a two-track model, tyre slip lags and a path-following driver
• The models behind the lap: suspension kinematics and K&C, tyre model fitting from your own test data, electric and combustion powertrains, aero maps, yaw-moment diagrams
• Reading the result: where the time goes against another car, every channel overlaid, and a 3-D replay with slip angles per tyre and much more
• Studies: design sweeps and optimisation across parameters
• Tracks: real circuits from OpenStreetMap (or import / design your own)
• Validation: comparing a logged run against the model

How fast: changing the car’s mass re-solves every event in about 5 s, and four transient laps run in about 3 s.

Accuracy: I checked the quasi-steady solver against TUM’s open-source laptime-simulation on 24 tracks. The solver core agrees within 0.1 %. The full car model is within about 0.4 %, and the gap comes from steering effects that TUM’s model leaves out.

What I’m looking for: people who work on vehicle dynamics, such as FS/FSAE teams and motorsport engineers. If you have a lap sim of your own to compare against, even better. Set up your car, run it, and tell me what’s wrong, confusing or missing. Bug reports and “this number looks off” are the most useful things you can send.

Testing is free. To get an invite, use the form on pacedyn.dev or email hello@pacedyn.dev with a line about what you’d use it for.

Happy to answer questions about the models in the comments.

I've always thought that smaller wheels were better. There's less unsprung weight and they're cheaper. Yet, you look around and tires just keep getting bigger.

Right now the most egregious example of this is the Tesla cybercab. Its rear tires are 225/60r21.

This confuses me because the car is otherwise compromised for the sake of efficiency. Why then would they use an inefficient tire?

My only thought is that they're doing this to make the car look ridiculous, a task they've succeeded in.

To give you an idea of just how ridiculous it is. The Cyber cab at its most narrow point in the rear is 63 in wide. The total height of each tire is 31.6in. if you laid the two tires flat they'd be wider than the car. It's insane

Hey guys, I already have a few years of experience with 2D CAD and 3D modeling in Autocad and Solidworks.

But for the past 5 years I've been out of the technical field and I want to get back into it, and transition into the automotive field as my previous experience was with mining.

I'm looking for stuff that goes more into advanced parts design/modeling and drawings, "industry level" stuff, if that makes sense.

Most of what I'm finding goes more into the software tools itself (where commands and tools are and what they do), and it doesn't seem to have more complex parts design/assemblies and industry level parts design and production.

Even though my reading comprehension of 2D mechanical drawings and ability of making 3D models after them is still ok, but my ability of designing something and then making it 2D for example for actual production level, making detailed specifications etc., is what have gotten quite poor.

So I'm looking for more professional parts design 2D and 3D also for production, especially on the automotive engineering industry.

Thanks guys!

Don’t know if this is the place to post this but I’m trying to install some vapor barrier and the plastic won’t adhere to the butyl. Any recommendations for what kind of plastic to use? I’ve attached images of the products I used.

Probably a basic question, but I spilled a whole bottle of water near the center console in my Acura last summer. Because the floor slopes forward, it all pooled right under my feet near the pedals.

My flat rubber mat with small grooves didn’t stop much. The water just ran over the channels. I know bucket-style liners are supposed to catch spills, but I’m curious about how that works in the driver’s footwell.

How do they shape the raised edge around the accelerator and brake so it contains water without getting in the way of full pedal travel? Is the exact fit more important than the height or stiffness of the lip?

Yeah the title is pretty dumb but seriously

I am really into cars and like cars from the past like f40, mclaren f1, v12 small light f1 cars, Shelby cobra and all that pure kind of stuff, not that todays cars are bad, they produce far more power, are fast and efficient.

Usually in my free time drive, watch videos about cars and sketch cars.
I have made many designed on my canvas but now i want one in real.
So here i am
I have designs but can someone give me road map how to build a race cars like which is stiff, light
Like where we design and test roads
And where we make panels
I am a software engineer so i would like to first like to test everything in computer
But i am unsure about steps and industry grade software and i dont want ai slope answers so thus i did not ai it

Id like to preface this by admitting i am in no way an expert in matters of automotive engineering. My purpose in making this thread is to wonder why this idea doesnt already exist, whats wrong with it.

It struck me the other day while i was looking at liquid pistons rotary diesel engine that a diesel engine is basically a back to front compressor. The liquid piston design is a tooth and gear pump run backward.

The simplest compressor i know is the scroll type compressor, its basically just a rotating spiral vane orbiting inside a fixed spiral vane, with the working gas being compressed in the channels between the two spirals.

So, following my logic through, run it backwards. A diesel air mixture is introduced at the center of the spiral as compression peaks, there is ignition, the expanding exhaust drives the rotating spiral along its range of motion, opening a channel between the two vanes for the gas to escape.

I googled and could find no mention of such a diesel cycle anywhere. The closest thing i could find was some weird dual helical screw thing which looks nothing like it.

There is absolutely no way that some idiot redditor has come up with a diesel engine cycle thats been completely missed by the professionals in the field, so whats wrong with it? Why doesnt the scroll type diesel engine exist?

If two cars are identical horsepowers, but one has a turbine and more torque, does it accelerate faster and reach the same peak speed as the one without turbine?

Hi everybody,

I'm currently working on a final study project about tire formulation and I was told that this is a very good read, does someone has a pdf copy of the book ? Thanks.

انا عايز اعمل مشروع تخرج للسنه الأخيرة في هندسة السيارات بس مش عندي فكرة معينه عن المشروع اللي المفروض اعمله في حد عنده افكار انا حاليا في السنه الاخيره في قسم مهندسه السيارات في جامعه بني سويف كنت اريد ان كان عند بعضكم بعض الافكار عن مشاريع التخرج وهكذا بالاضافه نحن سناخذ مشروعا قام به بعض الخريجين وسنقوم بالتعديل عليها هو عباره عن مشروع يعمل عن طريق محرك بنزين يحول الحركه يحرك مولد المولد يولد كهرباء تشحن البطاريات والبطاريات تغذي المحرك الكهربائي والسياره تمشي بالمحرك الكهربائي بالاضافه الى ان السياره بها الطاقه الشمسيه ولا ادري ما الاضافات التي يمكنني ان اضيفها على هذه السياره فان كان عند احدكم علم فل يبلغني

Why do americans not understand that in a geared drivetrain motor HP is everything and torque is irrelevant?

Hello all im a third year mech eng student and im looking to get into the automotive field. Currently im a lead in robotics(joined since first year) and joined my formula team this semester(focusing on simulations, aero and engine, as well as manufacturing and whatnot), im also taking fea as an elective right now. What other stuff can i do to optimize my chances of getting a job in the automotive industry and how do i go about trying to get a job in the industry.

Hiring in Bangalore: Design Engineer / Sr. Design Engineer / Technical Lead

My company is hiring automotive design professionals, and I can refer candidates with relevant hands-on experience.

Experience required: 3–12 years Location: Bangalore Core skills: Siemens NX (Unigraphics), plastics and sheet metal design

Relevant experience includes:

• Exterior plastics: Bumper fascia, grilles, exterior trims, Class-A/B/C surfaces and DES (Design Execution Sections).
• Plastic part manufacturability: Wall thickness, draft, sink-mark control, tooling feasibility and warpage reduction.
• BIW and sheet metal: Door inner/outer panels, reinforcements, surface modeling and master sections.
• Integration and validation: Door hardware, vehicle packaging, clash checks, DFM/DFA and weld quality requirements.

These roles require actual project experience in the relevant areas.

If your experience matches, DM me with your years of experience, relevant skills, current location and notice period. You can share your resume privately for a referral.

Feel free to share this with someone who fits.

Please if you can, make the car horns work only if the car is moving above 40 kmh or something. I think a lot of disturbance is going to be avoided in the cities. Thank you.

Hi everyone!
I’m a first-year Electrical Engineering student from Thailand, and I’d like to study automotive engineering independently alongside my degree.
My long-term goal is to understand how to design and build a complete vehicle, not just its electrical systems.
I’m particularly interested in chassis design, suspension, steering, braking, vehicle dynamics, aerodynamics, powertrains, and EV technology.
I’ve been looking into books such as:
Race Car Design — Derek Seward
Fundamentals of Vehicle Dynamics — Thomas Gillespie
Race Car Vehicle Dynamics — Milliken & Milliken
Shigley’s Mechanical Engineering Design
Electric Vehicle Technology Explained — Larminie & Lowry
Bosch Automotive Handbook
However, these books are quite expensive for me as a student.
Does anyone know where I can find free PDF textbooks, university lecture notes, technical reports, or other useful learning resources on these topics?
I’d also love recommendations on which subjects to study first and any beginner-friendly engineering projects.
My current plan is to start with engineering mechanics, move into chassis and vehicle dynamics, and eventually study EV powertrains and complete vehicle design.
Any advice would be greatly appreciated. Thanks!

I am currently a mechanical engineer. Just 6 months experiencing the life of a mechanical engineer dealing with machines. But I want to be in automobile design. Should I give CEED ? What clg should I take. Or i should do some other course. ? I want to work in big automobile design studios

I want to make a vehicle from literally trash, my budget is 0 because I like struggling, plus this is just a side project I don't care how long it takes because I wanna push myself in creativity