When Subaru Put a “Jet Engine” In Their Exhaust | Rocket Anti-Lag Explained!
Anti-lag systems help a turbocharger to continue producing boost when a driver is out of the throttle, but did you know that the Subaru rally team had one that could fully spool a turbo at idle? The Subaru Impreza WRX STi S11 and S12 WRC generations featured a unique system dubbed Rocket Anti-Lag. Using patented technology from Prodrive and similar principles to a jet engine combustor, the cars were fitted with a separate combustion chamber in the exhaust.
The system that drivers like Petter Solberg and Mads Ostberg got to enjoy has puzzled people for some time, so I decided to read through the patent documentation and try to understand how it works. So let’s learn how anti-lag works, then go over all of the awesome engineering behind the rocket system! This is Subaru’s Rocket Anti-Lag explained!
Timestamps:
00:00 Intro
00:45 How a Turbo Works
01:06 What is Turbo Lag?
01:45 What is Anti-Lag?
02:19 "Throttle Bypass" Anti-Lag
03:40 "Air Injection" Anti-Lag
04:21 How "Rocket Anti-Lag Works!
09:04 Busting Myths About Rocket Anti-Lag
Credits and References:
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Music List:
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Copyright Disclaimer: Under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. This video intends to follow and obey the guidelines set forth pertaining to fair use by using the original content in a transformative way to tell a new story. If you are the original copyright owner of material used in this video and disapprove of its use, please email the business email listed in the channel description and I will be more than glad to resolve any issue.
I just stumbled across this video, and was extremely pleased to see you cover a system I worked on during my SWRT days. I was the designer on this system, that was invented, developed brought to competition by Roland Broadbent. All the drawings from the patent you used were done by me. Some additional points: 1. No ignition system was used because the rules didn’t allow for a secondary ignition source after the engine spark plugs. 2. The idea came from a diesel French tank in the 1960’s that had what’s called a hyper charger, but that had its own ignition system. 3. Combustion in the chamber was initiated by the plate on the end of probe in the centre of the chamber, that flowed cherry red due to the hot exhaust gases coming from the engine. This plate restricted flow and reduced the top power of the engine. This later evolved to annular ring that was less restrictive to the flow through the chamber. 4. The boost tank used by Ford was illegal, but passed scrutineering when discovered. SWRT went the next rally with a bear barrel doing the same job. After that boost chambers on all cars were outlawed. 5. Different ALS systems were used on customer WRC cars. 6. A road car version was developed for STi by Prodrive, but never went to production due to cost and long term durability.
First off, what an amazing piece of engineering developed by you and your team! I'm absolutely honored that you would take the time to comment here and I hope I've done the system some justice! All of those additional points are much appreciated. I did my best to reason through the system's operation using the text in the patent, but I figured there would be some finer details that I may not have gotten 100% correct. A couple of questions for you: 1. Would you mind if I "pin" this comment to the top of the comments section so that others can easily find it? 2. Is there a good place I may be able to get in contact with you? Completely ok if not, but I thoroughly enjoy learning about motorsport engineering and would love to speak with you further on these kinds of subjects. If you don't want to share that info in a comment, my email is themotorsportstory@gmail.com Again, thank you so much for the comment!
@@themotorsportstory you did a great job of explaining a complex system. Happy for you to pin my comment. I’ll email you later. Cheers Darren
This is the best of what can come the comment sections.
Did it draw inspiration from a pulse jet?
Very curious what this hyper charger system you mentioned was like. Looking it up just kept giving me fast chargers for electronics or what is basically a ram air intake for motorcycles, no mention of cold war french tanks.
It's dissapointong how many of theese cool racecar features get forgotten in time while people make up stuff about what's that thing they're seeing rather than investigating it. Thanks for bringing us such great and interesting content!
Appreciate you watching! It can be hard to dig up information on systems like this, but I do my best to find what I can and hopefully make some sense out of it.
And that is why we have extremely underrated channels like this one😭
I have even heard some of these cars having water cooled brake calipers😮!
yea
@@crankybear1236 i think that the idea came from trucks or something like that, not sure though
It's literally the combustion section of a jet engine. People build jet engines using junkyard turbos and this is very similar to the combustion section of those engines. Awesome concept.
yep..that is right!
Hey, anyone here can tell we can replace the conventional anti-lag system with jet engine on a car or this idea is not practical?? ... Since the Subaru's rocket anti lag system is basically based on jet engine principle which supplies smooth and continuous turbulence for the spooling process.
This is nuts, the designers used what's called a can style combustion chamber on jet engines (albeit slightly changed) and fused the design with a resonator, and made an anti-lag system. Genius!
can you elaborate on that last bit? what exactly is the resonator resonating, and resonating with? my best guess is the combustion rings.
For anyone who worked in any capacity with turbine engines the rocket closely resembles a combustion chamber, with the most notable difference being the lack of fuel injector and instead an intake of fuel rich exhaust, which serves pretty much the same purpose of delivering fuel for combustion. The inner and outer tube design with holes are almost identical to what a turbine engine combustion chamber would have, except for the tube which is routed to the middle. It's very cool to see they pretty much made a jet engine in the exhaust.
What I kinda wonder is why they didn't go all the way and put a fuel injector into the can? That should (in theory) allow keeping the turbo at full boost at any engine speed all the way down to zero. You might even be able to (once you get the turbo running) get enough boots to air start the engine! My guess is that either the rule book already bans that (boring) or that there is some non-obvious reason it don't work well (interesting).
@@benjaminshropshire2900someone involved in making the device or at least the patent for it did confirm that the rules stopped them from doing that. (They're not allowed to have fuel injectors outside of the combustion chamber)
@@ergoproxy-gx2cq well that's a boring reason :-(
Great video, as ALS control engineer and without breaching any NDA you are bang on track when describing the solenoid control. I had heard of the no ignition source pulse jet type system being used previously , fascinated by the pro drive rocket and Darren James further comments, Maybe electric turbos could be a subject for the future. Keep up the great content.
Thank you! I've been impressed with how many people from the industry have been coming across this video and love that you have all been so kind and encouraging. Electric turbos are a great suggestion for a future video! I'll need to educate myself a bit more about them first :)
@@Republican_Extremest electric motors on turbos are not really a new concept, they have been in use ever since the new V6 hybrid systems were introduced in F1. A motor/generator is placed on the turbo that can help spool it up and can also help recapture energy when fully spooled-up. Fully electric turbos on the other hand has not seen the light of day on professional race cars.
Yes, I was thinking the same about the pulsejet not requiring an ignition source.
I absolutely love the engineering that goes into sports cars, but I absolutely sit in awe and wonder when I realize how much further engineers have to push when it comes to race cars. That pursuit of performance is just something that I can't get enough of because the solutions they come up with are pure genius. This video is informative perfection. Definitely subbing
Fascinating isn't it! Thanks for the sub!
@@themotorsportstory Most definitely fascinating 🔥🔥. It truly is my pleasure. Keep up the good work! 👍👍
Just have to say it, every race team cheats, and all of it is in the name of engineering.
They both push, just with different goals and constraints. You couldn't use this in a road car because the turbine doesn't last very long. Alternative systems exist like for example Porsche's which runs the engine at WOT but with no fuel under decceleration to keep air flowing through the turbine. Road cars have a lot more R&D spent on things like safety, efficiency, comfort equipment and of course cost optimization. In fact there's probably more R&D overall put into a Ford Focus than was every put into a Group B rally car.
just a modified gas turbine combustion camber
Very interesting stuff, initially I thought it would be mounted after the turbo because of the temperatures, but it all seems very well thought out! Thanks for the content!
Definitely a well-engineered system! Appreciate you watching!
Man Synchronicity is weird I've been studying this exact system for the last week. There was also one on a pretty "famous" S2000 based off the Pro-Drive design. You did a great job explaining.
Thank you! I came across that during my research, super impressive! Just found the link for anyone interested: kzhead.info/sun/pNSDibVxfauapqc/bejne.html
@@themotorsportstory Im going to utilize something very similar to the Air-box they used on the pro dive setup on my WRX Wagon build..
@@PrayItForwardAGAPE Awesome!
does based off mean based on now?
@GangBalls69_Estonia kzhead.info/sun/pNSDibVxfauapqc/bejne.html&ab_channel=RobertThorne The builder explains all. Other videos of his show it in operation.
Thanks for making a video on this. A very unique piece of motorsport engineering history
Thank you for watching it! It's really interesting, Prodrive's patent cites some older patents from the 1950s that also related to combustion chambers for turbochargers. But as far as I can tell Prodrive and Subaru were some of the first to use the technology in a major motorsport.
@@themotorsportstory WW2 and post war engineering was next level. So much innovations from that period.
For sure! Crazy what people could think of before computers even existed to help with design.
Strikes me as a design spinoff of the old, tried-and-true pulsejet engine. This is a rather interesting implementation of it, I must say. Well-presented, also, sir. Straightforward, no-nonsense approach; no "hollywood" nonsense or obnoxious music, etc.. Very well done. Thank you!
Glad you enjoyed, thank you!
Well it's funny, because I remember watching a youtuber make a pulsejet out of a car turbo, lol. That's why I see this as a jet engine and why they call it that, because it technically is.
I was about to say it reminded me of a Ram Jet.
was thinking the exact same
Cut out the piston engine and this is just a normal jet engine.
This is so cool. Thank you for taking the time to put this together and laying it all out so plainly so that it is easily understood, appreciate the effort my guy, awesome video!
Thanks so much!
SUBSCRIBED! Remarkable video dumbed down just enough but yet still providing PLENTY of details. Everything was damn near perfect In my opinion. Nothing annoyed me or felt like a waste of time. And I especially like how you didn't spend an excessive amount of time talking about the basics. Why on earth would anybody try so hard to explain something so basic then proceed to explain a really really really complicated subject. Thank you for the content! It's greatly appreciated :)
Thanks so much! I was having trouble deciding on how long to make the video and how much of the basics to cover, so I'm happy to hear that it sounds like I struck the proper balance.
Man! This was just sooooo well made and narrated! For a mechanic nerd like me this was amazing! Thanks man! Hope you'll grow your channel strong and continue making excellent content like this!
Thanks so much, glad you enjoyed it!
I dearly appreciate how clear you make complex issues for people who are totally ignorant(me) and the effort you put into busting myths. Very great
thanks for breaking down this system and putting it in (relative) layman's terms. this era of rallying was when i really gained an appreciation for the sport beyond the simple thought process of "woah, cool car go fast!" and your video has brought things full circle. subscribing after watching this video was a no brainer !
Thank you, and welcome!
Awesome video dude. Really glad I came across your video. The way you've described everything is easy to understand. Love things like that system, true engineering.
Glad you enjoyed it! I love learning and talking about systems like these!
Great video!! I've done a lot of research on the rocket myself and seen all of those technical drawings and patents you showed. Excellent work!!
Thank you!
Very entertaining and informative! I do have some basic knowledge of how turbo and superchargers work but didn’t know how anti lag works for the Subaru rally car. Very cool!
Subbed. This is the best description of this system I’ve seen in video or any form. I’ve tried to explain this to people but I know it’s typically lost in translation. But you’ve done a great job
I appreciate that a lot, thank you!
you deserve way more subs, really informative and well made video. Interesting topic as well, I had never heard of the rocket anti lag system before this
Thanks so much! Glad you enjoyed the video!
This is a really technical and genius solution. Race engineers never cease to amaze
Agreed!
Thanks for the content! I’ve been looking at antilag options for my 2017 Subaru STI and found the rocket! You explained it beautifully ..nicely done Brother!🤙🏾🤙🏾
Finally someone who made a proper video about such a cool piece of technology ! I knew it existed and how it worked, but in your video, I´ve learned couple of new things. Great job
Glad you enjoyed it!
Super interesting fact is a lot of race teams install an intake to exhaust bypass valve and then plumb in an injector or if it’s a DI engine they use a fuel delivery during the exhaust stroke. It basically works as an afterburner.
For anyone curious about the cooling system at the end of the video, here's a great article that explains pressurized cooling systems used in racing which is probably what these cars have: appliedspeed.com/blogs/tech/purpose-built-race-car-pressurized-water-systems I'm still learning about them myself, but the reason offered for adding pressure to the system is to check for trapped air in the system. From the article: "The tank comes with a Pressure Relief Valve (PRV). The PRV is adjustable, so it eliminates the pressurized radiator cap. The accumulator is also accompanied by a quick disconnect fitting for the operator to add some pressure to check for any air trapped in the heads." So minor correction on my part if that is what he was doing instead. Thanks for watching!
within the team , it was actually nicknamed rolands rocket, as it was designed by prodrive engineer roland broadbent
@@farmerbailey2542 True :)
@@farmerbailey2542 Interesting, thanks for the comment!
The main reason isn’t to bleed the system but to increase the pressure and prevent boiling of the coolant! In particular the most at risk area’s such as the coolant galleries in the heads above the chambers and exhaust ports as increased pressure raises the boiling point of the coolant and bleeding is a secondary benefit! Also just about every cooling system is pressurised but this is roughly twice a normal car’s pressure and with an additional accumulator it’s a practical and well thought out system! Edit should have watched before comments! You got the accumulation covered lol
@@needmoreboost6369 Interesting, so I was on the right track I guess! Thanks for the comment and for watching!
This is really great. Just keep up the great work man. Reading the patent, thats amazing
That was an insanely detailed and thought out analysis. Thank you!!
Great rocket explanation! I was fortunate enough to have an inside look at this during the first few years it was used on the S10. It was inspired by a design in a trash truck that was used to keep the DPF working with frequent start/stop, as well as Nick Mann's hillclimb car which used an actual turbine to keep the turbo exhaust pressure separate from the piston engine.
Thank you! I've heard about the Nick Mann car and would love to learn more about that! Any good links or videos you'd recommend?
@@themotorsportstory just search Nick Mann hillclimb and it should bring up some great videos. It's really a crazy car.
They might call it the Rocket because the idea is very similar to how a a part of a liquid fuel rocket engine works. A gas generator burns some fuel and oxidizer to power a turbopump, which is extremely similar to an automotive turbocharger. There are even engine cycles that run fuel-rich, then tap off some of the exhaust into the gas generator.
Good theory!
I thoroughly enjoyed this video. Thank you for taking the time to so thoroughly compile the info and organise it into a digestible summary for the viewer.
Wow thank you very much! Your video really cleared things up for me! My vague understanding of subaru's anti lag system was eye opening. Actually seeing the patent and having it explained was awesome! Thanks!
Glad you enjoyed!
Sounds awesome, too. I'm not sure if other WRC teams 'copied' this design, but many cars get the 'squirrel' type antilag sound which I assume comes, or is helped along to make that sound by this system.
Yeah I'm not too sure. I've heard that some British Touring Cars have used a system like this but I can't seem to find any info on it anywhere. Thanks for the comment!
Awesome video. Because of hybrid systems I doubt we're gonna see any more cool innovative anti-lag systems, bc the electric motors can compensate for the turbo lag without the wear on the engine.
Thank you! I think you're right. Unfortunately sometimes the innovations become less interesting as technology shifts and we can find simpler ways to do the same thing.
@@themotorsportstory correction: there's alot of underated innovation and cool tech happening in the EV space. Batteries, wiring, magnets etc. It's just a different field of physics that alot of car guys aren't used to
Battery weight kills this idea though. Until that’s solved liquid fuels have such a higher mass energy density that it’s not always the best way tho go. This is why the big boy drones all have liquid fuel powered electric generators (auxiliary power units) that then output the electrical currents to drive the prop motors. And it still comes out much lighter and more effective than having a battery pack.
I remember coming across the patent for this when researching mods for my own car, really great breakdown of the history of it :)
Thank you for going through all the information to cut it into smaller more understandable informative video🙌🏾✨️ definitely learned something new tonight😌🤝🏾
This system seems like it would be better suited for diesel applications. A less volatile fuel with more energy. Some diesel SCR systems run at these temperatures already.
That's an interesting point. I wonder if any diesel vehicles use something similar? I don't know much about diesel technology so I wouldn't know. Although I suppose reducing turbo lag isn't as much of a concern for heavy machinery.
@@themotorsportstory search hyberbar system at leclerc tank
Diesel works by compression though not heat or spark, I'm not sure it would work properly.
@@themotorsportstory it is a concern but it's mostly solved with vgts. Though this does sound like a good method for regen cycles
Diesel has a flashpoint of 100*c and a auto ignition temperature around 210*c so it will burn without compression. VGTs aren’t the most reliable and won’t give you full boost at idle just partial. They will limit the pressure range of the turbo as well.
Wonder if one could incorporate the simple 2step with an air injection valve to lower egts. Wouldn't be as good as this but might be a simple solution with more conventional systems
Absolutely possible, I actually have had this completed within the last week. The EGT can be seen lowering substantially via installed gauge.
@@SethPowers-mt2vz details please
Even after a decade or so, Subaru is something special to talk about! Amazing !
great video and really clear explanations, thank u for teaching us about it, bc I didnt know this was a thing. keep up the good work :) definitely subscribing
Skip to 4:20 for the "rocket part"
Unless you already know how turbos and anti-lag work, don't skip! :) Figured I needed to include a summary of turbos and anti-lag because I know some people don't understand it and without the background knowledge, you can't appreciate the rocket. Thanks for watching!
I've seen a lot of turbo system explainer videos. This is the first one I've seen where everything makes sense. I can't believe how many people get basic stuff very wrong in videos like this. Nice work and great job keeping it simple enough for the average person to understand.
Thank you! I put a lot of time in to the diagrams and explanations, so I'm glad to hear it paid off.
@@themotorsportstory good video
I hope this video reaches 1 million views and beyond! Because this is fascinating stuff that I absolutely love (though I understand little of it), and as a long time WRC fan, and race car fan in general, I am so glad I get to learn all this on KZhead!
Thanks so much!
Amazing video! Did get it endlessly recommended by youtube and i wasn't too interested, but i finally caved in and i'm glad i did, as i never had seen this explained so well. Congrats! You get a new sub!
Thanks and welcome!
Great video! I loved the technical analysis and going over these systems. Please more!
Glad you enjoyed it!
All of this made me happy! That was well explained and illustrated, nice work sir!
Thank you!
Bro you hit gold with this video. More just like this! Fascinating engineering
Appreciate that, thank you! I'm always looking for fascinating stuff like this, but it can be hard to find systems that are as thoroughly documented as this one. But believe me that once I do, there will be more 🙂
30k subs yet so good quality and informative content, hope the chanell grows fast!
Wow I understood most of that, brilliant explanation. Thanks 👍🏻
Oh, this video definitely earned my subscription! Absolutely phenomenal content right here. This is actually the second video I've seen from the channel, which is funny because the first video was the mentioned Ford Boost Tank video. I probably would've subscribed then, but if memory serves I watched it on a lunch break and lost was this channel to the infinite algorithm of KZhead. Not to worry, as 80% of my views go to car channels I was sure to find you again.
Haha, thanks so much and welcome back!
honestly one of the coolest videos i've ever watched
I lived behind the shop when they were in Colchester, VT, and the sounds coming from the garage was insane!!! (In a very good way). Even just visiting that small shop back in the early 2000's was so much fun. What a great era of rally.
That's an amazing piece of research you've done there, and very well explained.
I appreciate that, thank you! Not trying to claim that it's 100% correct, but I took my time to ensure that it's as correct as I could get it with the info I could find.
@@themotorsportstory As a patent attorney who works in the gas turbine engine field, I couldn't spot any errors at all. Really very impressive.
@@jackroutledge352 Haha, what're the odds?! I'll take it though, thank you! I'm just a car and engineering enthusiast that likes to share the passion with others.
This is the best comment section I've ever seen! Lots of insights and productive discussions, even from people that actually worked on the thing!? MAN this is pure gold! Amazing!
Agreed! People have been very civil for the most part, which is great.
As a racing fan I found this to be very informative. The commentary is nothing without a good presentation... and you sir, you nailed the whole packaged. Ill sub ya.
Thanks! Very much appreciated!
youre the real deal man. this took me back to my thermodynamics courses. I wish i had a prof like you!
Appreciate that! Makes those subjects much more interesting when there's cool stuff like this to apply them to!
Thank you for making this detailed video. It was a very interesting video and learned something new.
Wow this is the first video I’ve seen from this channel but it was very informative and in a way almost anyone could understand I’m about to binge
Glad you enjoyed it and welcome!
I actually kept up with that after working on my Imp over the last couple years. Thank you for the video.
Awesome, thanks for watching!
Subcribed just for taking the time to explain this! I love how race series make engineers find such solutions.
Thank you, and welcome!
Man you do a phenomenal job with these vids. Bravo
that explanation was so easy to understand and so short that is hard to do that was awesome
Excellent job on the explanation. Have watched another video but yours was more informative and understandable.
This channel will blow up! Amazing content!
Thanks so much!
watched the full video , interesting and actually didnt know about the rocket , and learnt something new today.
Thank you for this video, I learned something today! Keep up the good work!
Thanks, glad you enjoyed it!
You found a great balance between introductory material and advanced /new concepts!
Thank you! That was the aim, so I'm glad I delivered.
Excellent video! A complex topic explained simply, thoroughly and with great pace. + I learned something new!
Thank you! Love your videos!
Great video and very detailed! I’ll be looking for more you’ve done!
Thank you! Glad you enjoyed!
This was a good informational vid and needed to be posted! Thanks man
Glad you enjoyed it!
cool stuff, thanks for the entertainment, information and your elaborate work on the video. Amazing job :D 10/10
Appreciate that, thank you!
Really informative and easy to digest video. Awesome content for a small channel keep it up.
Thanks, will do!
Thank you for go through all the pain of reading all the page and explain it for us,,,,i subscribed
Appreciate you subscribing! Really wasn't too painful since I find this kind of thing super interesting 😂
That was really interesting. Some pretty cool engineering well explained. Just subbed 👌
Thanks and welcome!
Good job on the man splaning. Completely understandable. Very clever engineering for those rally cars.
Glad to hear it! Very clever for sure!
Amazing piece of engineering and amazingly informative video! :) Thank you!
Thanks for watching!
Man, thanks for breaking this down perfectly!
Appreciate you watching!
Greatest video about Anti-Lag ever. Thank you so much for making this. I am working on a video about anti-lag systems when I found this, starting from F1 in the '80s all the way to F1 today. But I would have never expected to find such a detailed explanation of the rocket tough. Best source I found was MotoIQ and Robert Thorne's youtube channel. Good thinking to look for a patent.
Glad you enjoyed it! Good luck with your video!
6:47 had me ROFL !! Seriously amazing explanation! subbed!
Great video ! Very well explained!
Awesome! Thanks for this detailed insights
*Best ever* break-down thank you
Rocket Subaru goes brrrr
Wow haha, almost 13 minutes of video precisely summarized in 4 words!
@@themotorsportstory thats how you know you understood what you just watched
great video, great explanation that's easy to understand. earned a sub!!!
Thanks and welcome!
I invented this tech in my mind one day and I'm glad to see someone else has also and actually put it to use
This "jet" is basically a preturbo exhaust venturi system, albeit one very well made. Good job explaining it!
Awesome video, truly awesome the explanations and diagrams, thank you.
Glad you enjoyed it, thank you!
Damn u really went well into detail. Thanks
Very nice video, learned something new, I will have to give that patent a look over.
Definitely do, it's fascinating! The link is in the credits section of the description.
Great content and keep up the good work...A new fan 🙂
Thank you and welcome!
Awesome video, very educational and yet entertaining. This is really some rocket science.
Thank you!
Like, Shared and Subbed! Hope to see this channel grow so much more. I've watched a few of your videos and I'm in love with the editing and the quick but subtle "subscribe plz's" too cute! I haven't stumbled upon any other channel that covers some of the topics you've been sharing with us so some of this is kinda new to me, and any new automotive knowledge is a plus in my books! ❤️
Thanks so much for the kind words, watching the videos, and subscribing. I like to find interesting topics that are less frequently talked about, so I'm glad to hear you're enjoying them!
I subbed because u did all the hard work of reading it for us!
Thanks, and welcome!
Cool video! I clapped for myself at the end too! This tech reminds me of a force fed pulse jet engine.
I actually wasn't familiar with those until I read up on them just now from your comment, so thanks for teaching me something! Glad you liked the video!
This channel is about to blow up
Thank you. I was looking for a video to watch and enjoy and instead I found what I was looking for for weeks. How to explain turbo and anti-lag to less tech knowing friends
Pretty damn crazy systems that work what people came up with👍
totally enjoyed all of this vid , thanks for making it !
Glad to hear it! Appreciate you watching!
@@themotorsportstory kind of you to say and reply
Awesome video thanks you for the break down 👍👍
Excellent explanation and comparison to jet engine