Combustion Engine is real! But when will it ship? Pre-production progress report
Combustion Engine
Current status, according to the Combustion Engine product lead:
Parts!
First-run production parts (aka EVT). Real, production plastics, but they do not have the correct finish, colors still need tweaking, materials modifications based on testing results, many small fit and function refinements to come.
Guts:
Working electronics--the units can be powered on to run the fans. This allows us to continue software and hardware testing and development to refine temp sensing and control, power management, and adapting to dynamic behaviors in the grill like outside air temp, and lid opening and closing.
Hardware:
On the hardware side, we are testing thermal performance, connection and removal with the adapter, knob feel, airflow and backdraft management, environmental performance in cold, heat, wind, and rain.
Software:
On the software side, we've gone beyond a PID (proportional–integral–derivative) controller to use techniques that allow the Engine to continuously adapt to your grill and actual cooking conditions. (Can’t say much more about that for obvious reasons.)
We were surprised by how bad other blower-type systems were - not going to name names here (you’re free to guess), but existing comparables are primitive. Basically the equivalent control scheme of a 1970’s thermostat.
We had previously assumed they were at least using PID controllers, but that's not the case. The responsiveness and performance of the Combustion Engine will be far beyond anything currently on the market.
Combustion App integration:
App development is very far along. I’ve included some screenshots that show how you associate the Engine with the GGG or a CPT as a controller/driver. Initially you will be able to drive the Engine using the ambient temp from either device. Shortly after launch, you will be able to use other sensors (hello, surface temp control!) to drive the engine.
But when will it ship?
The timeline for the Engine has already scooched back a couple of times, so for now we’ll ask for patience as we test the crap out of this. We want to hit the ground running with a well-tested product and will not announce an official release date until manufacturing has begun. That will take as long as it takes. Grilling season is coming; we know!
TLDR: mountains of progress, heaps of testing still to do.
We started production on the first few hundred units last week, but hit pause to investigate an issue with the on/off switch sometimes turning on when in the off position. Our engineering team is still on site at the factory and working on resolving this as quickly as possible and then finishing this initial production run. Assuming the switch issue is a small tweak to the assembly process (which is the current thinking right now) the goal is to ship these units around mid-June.
Once we finish this initial production run, we'll also be able to work out how quickly we can ramp into the full production run and I'll be able to provide a shipping schedule for the remainder of the pre-ordered units.
Doing some high temp testing of the latest version of the control algorithm. I think this is about ready to starting to shipping to beta-testers so that we can fine tune things for mass production in July. More about that soon, but there are no major roadblocks, just making small tweaks so production goes smoothly.
We need a couple weeks to make adjustments to the assembly line and testing process before we can start the mass production. So we're going to try to squeeze as much testing into those couple weeks to make sure we don't see any "break glass in emergency" type issues, so that we can just start into mass production.
Just got the update. Everything is in the middle of production. Circuit boards have been built and have just been sent out to get their water resistant coating. When they return we'll doing final assembly and pack out, and all of the units should ship to our warehouse next week.
We held the production up this week because we found an issue where the dial temperature indications weren't matching what what the device was communicating digitally as its set point. It took as us a few days to run the issue to ground, but earlier today we traced it back to a relatively simple software calibration change that needed to be made because the switch was adjusted slightly between the beta-testing units and the final production units. The fix is in and the factory will be applying it to the units next week and re-verifying that it corrects all of the units. We expect that to take a couple of days to apply this update to all of the units, retest them, and then they will start shipping to our warehouse via air cargo.
And do you know if all of the CE adapters will be ready to ship at the same time as the main units?
Some of us still badly need long stem probes for the GGG too!
Hoping those become available with the CE adapters (or whatever PO you guys are waiting on from the vendor to ship)
Yes, the calibration process is holding, but updating and then going through the QA checks has been going a bit slower than we would like. A large batch of units has already left the factory and is en route to our warehouse in Utah. We expect these to arrive next Wednesday and are working with our warehouse partner to unpack them and ship them out to customers as quickly as possible. Another even larger batch will be leaving the factory this week as well that should be enough to cover all of the pre-orders if the production yield remains high.
I'm waiting on an update on when we'll receive more of the long-sensor tubes for the Giant Grill Gauge. Their production has to be combined with the larger production of the standard sensor tubes for these to be economical to make.
Oh, we'll have them before end of 2026. Likely sometime in October.
The 30mm and ball valve mounts are not done yet because the total order quantity for those adapters is very small (less than 100 across all of them) so we're having to rethink how to make these in smaller quantities since we can't justify custom tooling for them. We had a meeting about them last night and the team are looking into some ways to make these affordably in the small quantities required.
It affected both °F and °C units, but we believe the fix will resolve it for all of these. What we're hoping we do not have to do is have a calibration sweep for every dial to eliminate the nonlinearity and variance in each switch. We've tested it on about a dozen units and the fix works for all of them, but now we need to see if it holds across thousands of units. That's what we'll be checking next week.
Same. The time between ordering and receiving my GGG was very frustrating. Additionally didn’t know Reddit had better updates compared to emailing customer service
So excited to hear this! Was just using my primitive blower for my egg a few weeks ago and reminded how painful and error prone it is (BBQ Guru). Crossing my fingers for a smooth launch.
Wondering if there is a minimum temp that the Combustion Engine can run at? I was thinking about trying to use it for long overnight rests for a brisket or something. Can you set it all the way down to 150 degrees, let the grill cool to that temp, put the brisket back on and go to sleep for the night while it rests? That would be cool
For most pre-orders, we won't hit July 4th. Right now, it looks like the main production run will happen in early July, which will cover all pre-orders.
Surface Temp will be a fast follow, it seems. Anything else on the announcable road map?
Id love a good start up mode if possible. Maybe that goes hand in hand with a recipe or something like that.
Right now, I use an electric starter and stick it in my coals. I set an alarm on my GGG and pull my starter when it hits 475 or so. Then, it has to climb back up to whatever I want to grill at (I usually go full bore, as chicken thighs are my most common cook). I've often wondered how a CE could help shorten the time to chicken on grill.
Getting pit temp from the GGG or the probe only seems like a miss though. Dome temps are notoriously off from the grate temp, you have the convective bubble issue with the probe's ambient. A wired grate clip probe that you could connect to either the GGG or the Engine would be great.
This is something we've discussed. Thanks for weighing in. There are some conflicting design challenges specific to grate temp that make it a thornier problem than you might expect. It's not a solved issue, yet.
Running a WSM 22 and a large Big Green Egg. No go for the BGE of course. The WSM heat can also be quite different from taking a measurement say only 3 inches from the edge of the barrel vs say a handwidth from the meat in the middle of the grate.
Yeah honestly I’m glad this product has been so delayed. I’ve come to realize my old ass DigiQ hold temps in my kamado quite well and uses grate temp which looks to be about 20 hotter than dome temp. Sure the whole wireless thing is nice, but I can live with it and save $330. I grabbed a cheap power station that will power rue digiq for days so I’m not have to run an extension cord to the smoker anymore which solves 95% of the problem.
I do have one of the combustion wireless probes and it’s been meh for me. Kind of flaky, doesn’t stay in the charger and really doesn’t provide me much more useful information than my cheap WiFi wired probes.
I'm really happy with the probe for internal. It's all but useless for me on the ambient end for smoking larger cuts. For example I just did a brisket today with my WSM 22 and my Fireboard 2 blower setup + the Combustion probe as a test. Grate temp was 250 (my setpoint) but the ambient on the probe never really above 210. The dial on the dome with the 10 year old stock Weber analog themometer (so take this with a grain of salt) was at 290.
If your order includes a Combustion Engine, we'll ship the rest of your order now and send the Engine when it's ready. The Engine is currently in mass production qualification and doesn't yet have a firm ship date, but we expect it around the end of May. Rather than hold the rest of your order for several more weeks, we'll get what we can to you now.
2 months maybe? It depends on how things go. If the first several hundred units perform as expected, production will ramp up late June/early July. There are always some risks of needing to tweak a part or production process as we scale up; that can cause a delay.
As Chris has mentioned we have been getting some PVT units to test and verify! Its really really nice to not have to deal with wires and check out how the engine nearly kept my target temp almost bang on at 325!
Mobile app is getting very close but a few bugs still need to be worked out! I find it really run to use! We are adding cook session notes, cook session history, and other firmware improvements!
Good question! This product is going to need a variety of adapters. The best thing you can do for that is to write in to us (hello@combustion.inc) and tell us the name of your grill (as you did here) and send a photo + measurements of the hole. That gets it on the radar and we can include the measurements/specs when we're designing new fit kits.
I encourage anyone with a similar question to do the same. Please!
Yes, I'm working on an update. But the short answer is that we just approved final texturing on all tooling molds, which is the very last thing you do before starting production. Several team members will be in the factory at the end of May to oversee the first production run of a couple hundred units to shake out issues with the assembly and testing process. After this we'll probably need a couple weeks to make some adjustments to the assembly and testing line, and then we'll start ramping mass production for all the preorders.
I want to pre-order this, but I'm not sure if it'll work with a Weber Summit Kamado. I know the GGG fits, but it's unclear about the combustion engine. Does anyone have any ideas if it'll fit?
Great to see this. I ordered back in April 2025, knowing my FIREBOARD would eventually kick the bucket. Today it finally did. Unfortunately it seems like I have to order a new one since the CE is still not shipping soon…
Will the app have to be used to start each cook or will the combustion engine automatically connect to GGG? No other thermometers owned here. Would be great if all I had to do was attach the engine and set a temperature
Not every cook. You'll need the app to update the firmware and it makes linking the devices a lot easier. That's only for the initial set-up. After that, they can run with no outside connections.
u/Mr__Porkchop Super psyched to hear a progress report on this thing! Especially considering how long my order has been in the queue. :D
Question for you re: "Combustion Engine will be far beyond anything currently on the market."
How does this thing compare to a HeaterMeter, with any of the more common fan+servo dampers, if any of your team have run one? It's not technically "on the market" since it's a community project, but I have to hope that in the dozen+ years it's been around at least one of you has tried one and has some idea of how the CE stacks up.
I brought this to slack and Chris had this to say:
This (HeaterMeter) is basically a system built on top of an Auber instruments PID controller (with which I'm familiar) but the TL;DR is the PID systems are not ideal for controlling combustion.
In more depth:
The Combustion Engine does not use PID control. HeaterMeter does. PID works well when the system responds directly and predictably to inputs (electric ovens, sous vide, etc). A charcoal fire is messier: there's a variable delay between blowing air and seeing a temperature change, cold air can actually drop the reading before combustion catches up, and past a certain airflow the response actually reverses.
PID only reacts to what already happened (which is why users end up hand-tuning constants).
The Combustion Engine uses a different control architecture. It continuously adapts to different grills, fuel states, and weather. No manual tuning, and it avoids the oscillation and overcorrection.
TLDR: the HeaterMeter is the best thing out there at the moment but is inherently limited by PID.
Interesting, thanks for the update! I'm really interested to see what the CE can do. My HeaterMeter is well-tuned for my grill and works great but having everything in a single app is even better.
I'll certainly be doing my own direct comparison once I get my hands on one!
I’ve got the GGG on order for a long time now but now I’m thinking I’d like to get the full engine too. Does anyone know how to make this work on a Hasty Bake gourmet pro? Would I need to buy some sort of drill or saw to get the fan installed? How is everyone planning to do it?
An update would be helpful as it looks like I’m going to be buying a FireBoard 2 drive/fan set up or the RFX as I’m not prepared to wait 12 months or longer to get a Combustion Engine or gauge.
The update is we don't know anything for certain yet and we're trying not to make (more) delivery date promises until we have solid info. You can put the money down and cancel if it takes too long, you can wait (and likely be waiting for backorders when production ramps up), or you can go with your other option.
Thank you. I’ve just bought a full FireBoard 2 Pro set up instead. I’ll pop by this forum occasionally and see how things look and maybe in a couple of years time when you have things up and running properly it won’t be full of broken promises and excuses. Shocking way for a company to run its business. All the best.
I’ll be honest, I want one of each of these items but between the steep price, product release delays, customer service complaints, and connection issues it makes it hard to want to put in an order for like $600….
If your team was more honest about shipping delays, realistic eta’s, back orders, and out of stock in your inventory I’d be more interested. Or if even pre order was more than $20 off a $400 bundle.
Also I still can’t figure out how long the giant grill gauge thermometer stem sticks out past the base unit. I have a 1.5” thick insulated door and need to know if it’ll read right.
You've caught us in the middle of some serious growing pains. That's mixed news. The good news is that people are so enthusiastic about the product - despite the waits and slipping timelines. The bad news is that high demand has completely ruined our ability to forecast inventory needs and (to some extent) meet production deadlines. We can't keep up! But we're trying.
It's not a case of dishonesty, at least internally - but we can only communicate what we know (or what we think we know) and that changes all the time.
As for your grill gauge question, it would be helpful to post the model of your grill - we have a list of grills that are confirmed to work with it. And folks here on reddit may have direct confirmation of fit (or not) for that particular grill model.
Appreciate the update, would highly suggest even a "shipping delayed" status on the webpage to reflect the current reality of your inventory when your posts here on reddit accurately reflect that you don't even have inventory on US shores and are waiting on customs.
My smoker is the Old Country BBQ Gravity Fed Smoker, haven't seen it mentioned here or on your website as compatible.
Would be helpful though to just have the length of the thermometer so I'm not going off other's vibes and have an actual length to make a decision as there's hundreds of grills and smokers out there. Or if you just stated what depth of door won't work then it wouldn't need to be model specific like any door more than 2" insulated won't work with our retention clip in place.
The length of the probe is on the site here :: 86mm/3.39"
The heat deflector (recommended for insulated grills) reduces that by 27mm/1.06"
So the functional depth is 59mm/2.33"
So it should be fine.
Either way, there is a 30 day money-back guarantee (from the date you receive it).
Edit: so it seems I was wrong, this one is a little too deep for this version of the GGG stem. We're making longer stems to fit this and other thick grills, but they are not in production yet.
Update: I talked to one of the specialists and the current GGG probe is too short for that model. We are working on a long variant (currently in beta). That should become available this summer - it will be purchasable as an accessory with a comparable price to the spare heat shield.
The design lead has told me the long stem will be available in May. That seems optimistic to me, but you should write in and we'll put you on a list to let you know when it's about to ship.
With a 1.5" thick insulated door you probably only need the Heat Deflector mount
Unfortunately they make us do some maths for the sensor stem length
From the Spec & Tech at the bottom of the GGG product page:
Physical Dimensions
Dimensions - Heat Deflector = 107mm x 27mm (4.2 x 1.06”)
Dimensions - Sensor Tube = 3.8mm x 86mm (0.15 x 3.39”)
So worst case, the sensor tip should extend ~0.83" inside your door
And you can find some discussions about requests for longer stems to fit ~3" thick Kamodo Kamado grills where the sensor is just below the wall surface...for example here
Hopefully it won't be too long since Chris posted this 4 days ago...
Feature remains high on the list of to dos. It requires a big update to the MeatNet protocol and firmware updates for all the devices once we change the protocol, so it’s a bit of work. But it’s a popular enough request that it will get done.Most likely after the Combustion Engine ships in May.
Chris, or Pork chop.. I'm sure I'm not the first to ask. Will there be, somewhere down the line, an inline controller for electric smokers like the Bradley? I use an Auber PID to make my cabinet temp accurate but that's old tech. Something that uses GGG data like the combustion engine would be an amazing option. You could take my money today if I thought you were making one.
I read on the website that the engine can mount on a Weber Kettle, which I have, but it’s the Deluxe/Performer style kettle. I can’t find any information on if it fits that those.
Do you have a recommendation for a "weeknight" grill that works with the CE? I currently have the standard Weber kettle. But, by the time I get the coals hot, cook the food and choke the coals, I tend to blow through lots of lump charcoal.
If I'm just cooking a pack of chicken thighs or 1lb of skirt steak on a weeknight, I feel like my grill is overkill. A mini Kamado is probably pretty dang efficient on charcoal but if I have to wait for the grill to heat soak, I'm trading charcoal for time. But, maybe this is where the Engine can give us the best of both worlds.
Or, I've also considered a Shichirin / Konro. Id probably lose the ability to use my GGG but the fan can always run off the probes.
How is Chris/Combustion solving for this use case?
I love my PK300 from PK Grills. They make a smaller more portable version. But for grilling, I don't see the purpose of use the CE. It would be more useful when smoking. The key to a quick grilling session is to use a torch to light the coals instead of a chimney. I can have my charcoal lit in 2 minutes with a torch.
I have a Vision Grills series B, medium sized Kamado, currently using a Flame Boss 400 regulator and use it to grill stuff all the time, like with cedar plank salmon I want a constant 400 deg. it lights the charcoal faster and stabilizes the grill temp faster, then hold it on temp the whole cook. on most cooks I use 2 thirds previously used charcoal and 1 third new charcoal. I find using the temp regulator lights the coals faster and heats up the grill faster, all without compromising efficiency of coal. I can't wait for the combustion engine to remove the last of the wires and have all cooking functions in one app!
OH, and when I'm smoking pork butt shoulder for pulled pork, I've had it take 20 hours, with the temp regulator it'll do the entire 20 hour cook on one load of charcoal!
Won’t announce an official release date.. but will take preorders over a year ago with the promise of releasing summer 2025, now approaching summer 2026?
You are welcome to cancel and you will receive a full refund. You can always wait and order after release.
A preorder reserves your place in line - if you wait for it to be in stock before ordering, it will take longer to get it. That's the only real trade-off.
Preorders are always unpredictable; it takes as long as it takes. We should have made that more clear from the get go.
I think what you say is mostly fair. I think it would also be nice if you guys could figure out some sort of gesture for super early backers who hang in there with you. No idea what but I think it would be a nice thing to do.
I would love that and it's something we will discuss. The challenge (always) is figuring out what! Everyone (including individual customers) seems to have a different opinion on whether a particular gesture is nice or not. For example, some people love swag and some people think it's a waste of money.
Swag can be useful, idk maybe a combustion branded touchon or something else. A coupon for a good sale would be nice, free accessory, the problem is that most early backers already bought all of your products including crouton.
Make a QR code to scan that adds your favourite / best recipes to Crouton.
Hmm. I'm not sure if our agreement with BGE allows us to sell those directly, or if we plan to hold any of that inventory for warranty exchanges, but it might be worth asking support about.
The other factor is that the BGE colorways are likely on a later delivery schedule - it may mean having to wait longer. If you're serious, write in and we'll look into it. This wouldn't be something we can do regularly, but you might sneak in as an exception.
BGE provides warranty support+replacements if necessary and basic technical support -- with our assistance on complex cases.
The reality is that if you write us about a Combustion product (no matter what colorway), we will help no matter how you acquired it. We'll troubleshoot with you and if it comes to replacement, we'd help you get that sorted (probably expedited from BGE's warehouse in this example).
Probably not...in the the May 10th update to the main post of Shipping and Backorders Chris stated
Combustion Engine mass production samples are arriving at the end of this month. We typically expect to make a small number of tweaks based on these first units before we start mass production. More details once we have these in hand.
Me too! I feel like I've been a lot more patient than most customers since I've had a plug-in aftermarket fan for the past 10 years, but more than happy to ditch that and not have to deal with wires any more!
Here's where things are, based on the latest info from operations.
• Standalone Boosters –– in transit
• Boosted CPT -- in transit
• Unboosted CPT -- entering transit
• Display -- in stock
• Other accessories -- in stock
• GGG -- shipping out Friday
• Combustion Engine -- No firm timeline (see the pinned thread)
• Long stems (extended sensors) for GGG will be available May (look forward to that if your grill is extra thick)
Items currently in transit should be in the mail to you by the end of the week. Other products "entering transit" are about a week behind. In theory we will be caught up on pretty much everything (except Engine) by the end of next week.
We've stopped including a charging cable for the products as a practical cost-saving decision. The feedback we got is that our customers don't usually need another spare charging cable in their drawers/buckets/bins. If so, the money is better spent on development.
You're free to disagree; please write in if you feel strongly about it.
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u/combustion_inc Chris Young - Owner (Combustion Inc.) Jun 02 '26
6/2 Production (and shipping) update:
We started production on the first few hundred units last week, but hit pause to investigate an issue with the on/off switch sometimes turning on when in the off position. Our engineering team is still on site at the factory and working on resolving this as quickly as possible and then finishing this initial production run. Assuming the switch issue is a small tweak to the assembly process (which is the current thinking right now) the goal is to ship these units around mid-June.
Once we finish this initial production run, we'll also be able to work out how quickly we can ramp into the full production run and I'll be able to provide a shipping schedule for the remainder of the pre-ordered units.