Very cool! I love the Volvo 940- it stands out as one of the best quality, and best designed cars ever made. It's an incredibly mature design evolved slowly from the Volvo 140 in the 1960s through the 240 in the 70s and the 740 in the 80s, and by the 940 they worked out almost any possible issue. I only wish one could have gotten them with AWD and a fuel efficient diesel (they had the latter but it was not sold here in the USA).<p>The author seems to have a lot of electrical hacking knowledge, but didn't know some car stuff that could have made getting these controls installed much easier:<p>1) They could have just swapped in a newer BOSCH ABS pump, which can activate the brakes electrically without involving the brake booster. European cars started getting these when they got traction control in the late 90s, but I believe some would be virtually (or maybe even exactly) a direct swap into this vehicle. I was able to do this in a VW with about 10 minutes of work, which uses the same basic ABS systems as Volvo. This is assuming the car already had factory ABS which I think most (but possibly not all) 940s did.<p>2) They could fix the steering problem by swapping in an entire electric steering rack- they're fairly standard dimension wise, installing a fully manual rack from a Volvo 240, or adding an A/C compressor clutch to the hydraulic power steering pump to disable it above parking speeds (the only time torque would be high anyways). Moreover, these racks are strong enough to simply work with the hydraulic assist removed, because people in the Volvo racing/performance community do it all the time.<p>3) This car does not have a carburetor- it is electrically fuel injected. You can see the fuel injectors and rail above the throttle body. This could be just a mistranslation if the author is not a native english speaker. However, more importantly there was a factory system on this car to electrically control the throttle for the cruise control. They are missing those parts, but they are cheap and common, and would have just dropped in to a bracket and cam already on his engine. They consist of a vacuum servo on the throttle itself connected to a box that can actuate this with an electrical signal.
>This is the only major actuator that I couldn’t easily find a suitable modern automotive solution for. This is mainly because newer cars don’t have carburators anymore, but rather use direct injection and advanced engine control units.<p>Actually injection system is largely independent from throttle control. Required amount of fuel is calculated based on manifold air pressure sensor, so there were cars with fuel injection and cable operated throttle plate. I suppose the problem was with plumbing in modern throttle body as carburetor needs to be upstream of throttle plate.
Amazing story! I have been involved in openpilot development for the past 5 years, and I am always interested in the user stories of this project.<p>I drove my car 2500 miles on Openpilot this holiday and it was wonderful. I took over maybe 10% of the trip and let automation handle the rest. That said, there are many many many areas of improvement and I have devoted this year to creating an openpilot fork to bring it's ADAS functionality closer to modern vehicles (read: tesla).<p>I will Show HN the first release!
Very cool. But is this allowed to drive on public roads in Sweden? I would have assumed that swedish laws are very restrictive to these kinds of DIY modifications. Amazing if it is allowed!
> Luckily [the accelerator servo] is also the only actuator that doesn’t come with major safety implications<p>This is giving me chills, what if that RC servo gets "stuck" at full throttle? I suppose the assumption is you could hit the clutch, but depending on the specific situation there might not be a lot of time for realizing what's happening and reacting accordingly.
I assume part 2 will cover gear changes. Whilst not addressed directly, there are hints that it's a manual transmission (which would square very well for a 1993 Volvo bought in Europe), such as the clutch also being operated with hydraulics. I doubt a retrofit of a new transmission is in store, perhaps a clunky automatic clutch instead?
This is fantastic. I've been wanting an RC car for years, but I've never bothered to buy a car for this. This post has inspired me to try it myself in 2025, though mine will probably not be self-driving.<p>I really enjoyed this post, well done.
Nice project. Wow.<p>Sidenote: Since 2018 all my cars are carbadge. Restored fully a CLK 200 Kompressor and Jaguar X308. I cannot stand the current cars. Neither designwise nor tech.
There is a lost art of honest design, aesthetic and pure functionality in today's automotive logic.<p>All the infotainment needs you have is live in your phone/tablet. You can use it with every carbadge car you can imagine.<p>I enjoy my cars. They are stylish and reliable. Something that I would not say about my 2016 BMW 6.
Next stop Toyota Land Cruiser from 1995.
I must say, the elegance of a vacuum brake booster stands out in contrast to the electrical variant. Barely 5 parts, stamped steel probably.<p>Then, in contrast, the electric power steering assist seems so much easier compared to hydraulic, just because of the fuss that hydraulics introduce. I may be a bit biased from dealing with rotted 90s hydraulic power steering systems.
Comma is actually hosting a hack in February, if anyone is feeling up to trying something like this on another "vintage" car<p><a href="https://blog.comma.ai/comma-hack-5/" rel="nofollow">https://blog.comma.ai/comma-hack-5/</a>
Very interesting build. Safety-wise it seems fine with the blatant exception of welding the steering column. A steering column could see very high torque, especially if e.g. power steering fails. The author even alludes to this twice but does not address it directly.
I must be getting old because this blog post scares me to death. Knowing this will be sharing roads with me, scares me. And it's not the DIY:ness, I don't care if this blogger is 10x more competent than all the engineers at Tesla, I don't trust a machine with my life or my family's life.<p>Obviously it's illegal so I don't expect them to use this while in Sweden.
> we also fitted a Tesla Continental radar sensor behind the front grille<p>Aha! So the obvious radar plate most manufacturers mount in an aesthetically horrible way directly in the middle of the grille is in fact complete lazy bullshit and it could easily be hidden without performance loss. The more you know...