What makes a TURBO STRONG? - BOOST SCHOOL #9

so here we have two turbochargers now looking at them from the outside would be hard pressed to find significant differences between these two turbos other than the lettering and the compressor wheel housing the compressor wheel itself and this little fitting right here they're pretty much identical from the outside and it's no wonder because they're the same turbo with nearly identical specs on everything but what's interesting is that you could buy almost four of these for the price of one of these so why does this one cost almost four times as much well that's because this one is a lot stronger than this one and today we're going to use these two turbochargers as an example we're going to analyze each of their individual parts to learn what makes a turbo strong and better capable of handling high boost a lot of abuse and more extreme applications the first thing we're looking at are the turbine housings and as you can see they look very similar however they are pretty different because they're made from very different materials the turbine housing on our low-cost turbo is made from nudge or iron while the turbine housing on our more expensive turbo is made from stainless steel now stainless steel is definitely a superior choice when it comes to turbine housing materials because it has a much higher temperature resistance and a better resistance to oxidation the turbine housing and the turbine wheel make up the hot side of the turbo and are the part of the turbo that is exposed to highest temperatures due to its direct contact with exhaust gases stainless steel has a much higher temperature resistance than nodular iron and because of this it's more stable under high temperatures which means that it's less likely to crack or distort when exposed to high heat and it will also better cope with the numerous heat cycles a turbo has to go through gasoline engines on average have much higher exhaust temperatures than diesels and this is why you will see stainless steel turbine housings on many modern oem gasoline applications while niger iron is usually found on low speed diesel engines while most oem automotive high speed diesel engines are also equipped with stainless steel turbine housings max beating rods claim that the turbine housing on the low-cost turbo resists up to 700 degrees celsius while their stainless steel turbo resists up to 900 degrees celsius the more expensive turbo is also marketed as a racing turbo and this higher resistance to temperature is definitely beneficial in racing where the engine is constantly exposed to maximum loads which leads to prolonged exposure to very high exhaust gas temperatures and temperatures of 900 degrees celsius definitely aren't unheard of temperatures can be especially high in sports like drifting for example where the engine is under massive holes all the time but much of that hold is used to get and keep the vehicle sideways as opposed to getting it to move as fast as possible in a straight line or through a curve which means that the average speeds over a drifting track are lower than in most other motorsports while the loads are still very very high the high holds mean high temperatures but the hole speeds mean reduced cooling effects and reduced heat dissipation from under the hood this means that the nitro iron turbine housing isn't really well suited to a racing application if you raise the iron housing and then went a step further by adding a turbo blanket to keep all the heat inside i am certain that its life span would be very much reduced this iron housing is thus much better suited to street applications where roads are constantly varied and temperatures are on average much lower also the turbine housing is usually the single largest and most expensive part of any turbocharger so nudge or iron which is one of the most affordable materials there is is one of the key reasons behind the difference in price between these two turbos now we're moving on to the compressor housing and both of our turbos have the compressor housing made from the same material and this is because the cold side of the turbo which is comprised of the compressor housing and the compressor wheel doesn't really see temperatures that are nearly as high as those on the hot side and this is why thermal resistance and the material employed isn't really as important on the cold side as on the hot side now both of our compressor housings are made from the zl104 aluminum alloy now this is actually the name according to the chinese gbt standard but the iso international standard is aluminum silicon 10 magnesium now this is globally a very popular aluminum alloy and it's traditionally used for casting especially of parts that have thin walls and or complex geometries of which a compressor housing is a clear example now as aluminum always go it's pretty tough with a good hardness and good strength on top of this it's not terribly dense so parts made from it aren't terribly heavy and it also has good thermal properties and on top of this it can be shot pinned welded machined polished coated whatever whatever you want to do with it this alloy is going to take it pretty well it's actually so user friendly and such a good all-rounder that it's also being increasingly used in additive manufacturing or 3d printing because it's not terribly dense and the final the finished parts made from it are actually pretty strong now the zl104 and its various international equivalents are used extensively by oem aftermarket and other manufacturers all around the world it you could almost call it a default choice for compressor housings you will find inferior alloys such as the zl101 or the zl102 employed by some weird obscure no-name brands honestly today in the market it's you would struggle to find stuff like this of course if you do find it i suggest that you avoid it in general when it comes to compressor housing materials there really isn't that much to worry about unless the application is truly extreme in all other cases you will find that pretty much all the turbos on the market today are using a decent aluminum or aluminium hour if you will and there really isn't that much to worry about it actually might be better in many cases to focus on the actual fit and finish of the compressor housing and that is to say to look out for obvious imperfections in terms of casting and machining as you can see the housings are off and next we're taking a look at the compressor wheels themselves and here we have our first striking difference between the more expensive and the less expensive turbo and as you can see the compressor wheel on the more expensive turbo is made from gold this is why it's more expensive and it also means that every time it spools it makes rain [Music] actually no according to max speeding rods the gold color on the compressor wheel is actually a titanium coating now titanium coatings definitely do have benefits in some other applications but when it comes to compressor wheels coating a compressor wheel in titanium really offers no significant noticeable benefit i'm pretty sure this was done to visually separate the more expensive turbo from the less expensive turbo and maybe to help the more expensive turbos stand out in the market more or something else but really the gold color isn't that relevant and we don't really care about it as you can see the the blade design is different but that's content for for a future video and just like with the compressor housing when it comes to compressor wheel the material really isn't that relevant so we don't care about the color or what it's made from or or whatever else what we actually care about when it comes to comes to a compressor wheel is how it's made as we said both of these compressor wheels are aluminum but this one is cast and this one is mfs or machined from solid in other words this is a billet compressor wheel so why is this one better well it's better because of the same reason anything billet or forged is better than anything cast when it comes to automotive applications and it all comes down to the internal grain structure of the part the grain structure refers to the size and orientation of the little microscopic individual grains that make up a chunk of something the size and orientation of these grains depends on the type of the material but also on the way apart from that material is made and a parts grain structure ultimately plays a key part in its strength the more uniform it is the better auto casting has come a long way it is still impossible to prevent a realty random grain structure with cast parts and it's also difficult to guarantee that there will be no internal porosity especially when using low tech casting methods on the other hand the billet process is completely different it starts out with a solid chunk of metal that has been previously forged or extruded giving it a good grain structure the next step is to simply machine away whatever you don't need from that chunk until you're left with the desired final shape of the part all while preserving the original grain structure of the bullet the ultimate result is a stronger part that can withstand more abuse and higher boost although it may seem that a compressor wheel is only pushing air high boost pressure rapid pressure fluctuations and massive surge can actually blow a compressor wheel apart and this means that mechanical strength becomes an extremely desirable property in racing applications in addition to making them stronger there's another benefit when machining things from solid and that's that you can also make them lighter to make up for the lack of strength cast parts must have thicker walls whereas billet parts can be much thinner you can easily observe this on our two compressor wheels if you look at the part through which the shaft goes it's much thicker on our cast wheel less material means less weight and less weight means that it's easier to spin the wheel up to speed resulting in faster spill times our next stop is the turbine wheel and of all the parts in the turbo the turbine wheel has to survive by far the highest temperatures which means that again material choice is very important for turbine wheels max beading rod says that these turbos use special k418 and k419 alloys respectively now what the k418 and 419 is is again the chinese gpt standard and an equivalent alloy is something pretty famous and it's actually incannel to be more precise it's incandel 713c which has been the default choice for turbine wheels for probably decades now in canal is essentially a nickel and chromium-based super alloy that has some very attractive properties when used in high temperature and high pressure environments when exposed to very high temperatures incanno forms a very thick and stable oxide layer which protects the part from further adverse effects of heat thanks to this oxide layer inkano remains completely stable at temperatures usually up to about 900 degrees celsius and also thanks to this layer inkano is very well protected from further rust which means that it can happily survive one of the harshest environments imaginable for years now incandel and its international equivalents are pretty much the default choice for turbine wheels about i don't know 90 of turbine wheels out there are going to be made from inconel 713c or the chinese standard or whatever other international standard equivalent of this hour with the same contents now some more advanced turbos aimed at more extreme applications can have different more advanced more high-end income alloys while at some of the really top stuff you can find titanium aluminide or gamma ti which you can find for example in the borg warner efr turbos but this is this isn't really making the turbine wheel dramatically stronger or more resistant to heat it's actually making it more suitable for motorsport use by having the same or very near uh the heat resistance and and strength of inkanel while also being dramatically lighter which dramatically improves boost response but this is stuff for pretty serious competition levels and an enthusiast would have a very hard time justifying these materials so for uh i don't know 90 of applications out there inconel and international equivalents are definitely a really good choice and you're never going to have issues with them our final stop for our turbo strength analysis is the core now i won't be disassembling either of these two turbos because although you can make manual markings on the turbo putting everything back together into the very exact same spot is next to impossible turbos are especially dynamically balanced on special machines and once they're balanced nobody touches them which means that by disassembling things you're actually running the risk of distorting the balance of the turbo and although many people do it and put things back together and don't hurt anything it would be a good idea to recheck the balance so i'm not doing that but there really isn't any need to look inside the core because many good people have done this already in posted videos and thanks to them we know that the inside of these turbos is actually pretty good and made some pretty high standards so instead of actually looking inside the core i'm going to show you this pretty picture which actually does a better job of teaching us what's inside the core now both of these turbos are pretty identical inside and are full folding journal bearing turbos now i do plan to make a detailed comparison video between ball bearing triples and journal bearing turbos in the future so for now all i will say is that although many people prefer ball bearings and they do offer faster spool and are ultimately a superior choice in many aspects there are still significant benefits to be had from journal bearings what you already do know thanks to people like jk fab whose max speeding raw turbo teardown video you're seeing right now and there are also links in the description is that these mag speeding rods turbos use pretty wide journal bearings and these bearings are great for minimizing radial shaft play but other than the journal bearings themselves the other part of the strength equation inside the turbo core is the trust bearing which has the task of minimizing axial plate again thanks to jk fab's video we know that the truss bearing inside this turbo is a 270 degree bearing which isn't bad and it's pretty standard in the industry but i was curious what was in the racing turbo so i asked max beating rods directly i was told that a racing turbo also has a 270 degree thrust bearing which is a bit disappointing because a 360 degree thrust bearing would help improve longevity in general a 360 degree thrust bearing provides greater oiling and shaft protection under high thrust holds which are present at high boost a 360 degree bearing is also critical if you decide to run a small turbine wheel combined with a large compressor wheel in the case of both of these turbos the turbine and compressor wheels aren't mismatched which does help but still a 360 bearing would definitely allow for better longevity in racing conditions so to summarize the more boost you want to run the more you want to raise the more extreme your application the more mechanical strength and temperature resistance you're going to need so if you want to tinker around a bit and experience the joys of boost then you can get this ridiculously priced turbo but you can't realistically expect this thing to last in racing conditions or to last many years if you decide to daily drive it also you can't expect it to last much beyond around 15 psi or one bar of boost but it's still absolutely incredible value for money when you realize that you get a pretty well made working turbo charger for what's essentially the price of a relatively fancy launch for two which means that it's an ideal fit for a fun little non-daily driven project car that you want to race maybe only occasionally and i like that max beating rods is realistic with this turbo and they tell you it's gonna give you a 20 to 40 percent increase in power compared to an eco naturally aspirated engine and that's pretty objective and something that you can realistically expect from this turbo but if you want more than that then you can buy this guy going to take more boost more heat it can race and although it looks kind of expensive compared to the ridiculously priced turbo it's still incredible value for money compared to most other options on the market now max beating rods claims that this turbo can survive three bar which is 45 psi of boost now honestly i'm i'm skeptical of that and although you might make it somehow survive 45 psi of boost i'm pretty sure it's not going to survive it for long that being said anything between 15 to 20 psi it's definitely going to be happy there it can survive you know quite a bit of track days so for around 400 you're gonna buy quite a bit of track time at some pretty decent boost levels which again for this price is honestly pretty fair so yeah that's pretty much it when it comes to the basics of turbo strength i hope you liked this video and found it useful i also hope it helps you make better more informed choices the next time you decide to shop for a new turbo as always thanks a lot for watching i'll be seeing you soon with more fun and useful stuff on the d4 channel

Channel: driving 4 answers

Views: 212,017

Keywords: turbo, turbocharger, boost, racing turbo, billet turbo, billet compressor wheel, ball bearing turbo, journal bearing turbo, maxpeedingrods, turbine housing, inconel, compressor housing, turbine wheel, ebay turbo, cheap turbo, chinese turbo, borgwarner efr, garret, gt28, garret gt28, boosted, boost control, boost school, alloy, aluminum alloy, k418, turbo thrust bearing, forged turbo, stainless steel turbine housing, turbo explained, how a turbo works, turbo sound, turbo flutter

Id: py9E6yOuzgI

Length: 16min 56sec (1016 seconds)

Published: Sun Aug 15 2021