Turbo Your Car - Choosing a Turbo

So you want to

turbo

your

classic car, you want to make a lot of cool noises, you want to make some power, you want a bunch of guys to think you're cool and you want to be a booster, but there's a lot to do. It can be so overwhelming. How do you choose a

turbo

? How do you know that everything will work? How do you prevent the engine from exploding? How do you keep things fresh? And, most importantly, how do you choose the right turbo? That's what we do. What we are doing today honey, it is the third part of the six part turbo saga, today we are talking about turbos, a great vacation thanks to ridge wallets for sponsoring this episode, does anyone else feel that wallets are becoming more and more like suitcases today, oh, my back, oh, for sponsoring this. episode anyone else feels damned on my gift receipts future jokes no one is 20 20. no one needs gifts for seats and if you try to put that in

your

back pocket you'll break your back and you won't even make it home for christmas let alone listen santa's sleigh santa slate people really liked that episode of up to speed yeah they did there's no reason to check it now why don't you grab this?

The Ridge wallet doesn't bend or bulge strangely in your pockets it's about carrying less and always having exactly what you need this is great it's a pain people have to wait until the future to get one oh contrera nolan the future is here everything what you have to do is go to ridge.com donut and use the code donut to save ten percent but you have to hurry because time is of the essence wow future job you have really saved us from many painful scenarios you deserve a break maybe do it nolan maybe do it thanks ridge wallet okay so this is the kit we have the cx racing kit last week we installed the turbo manifold and talked about downpipes which means this week we are ready for the damn turbo itself, which is super exciting but also a little daunting because there's a lot that goes into this and a lot of things to talk about, what are all these different numbers and sizes and measurements?

Well, buckle up, babies, because we're going to talk about it today, at the end of this episode, we'll have a bolt-on turbo. the miata so get ready I'm excited here it's the turbo we've all been waiting for so let's get into it but first let's talk briefly about how a turbo works. The two sides of the turbo, the hot side and the cold side, the hot side is the side that deals with the exhaust and the cold side is the side that deals with the fresh air that is sucked in from the atmosphere and then accumulates in the motor.

The exhaust gases pass through the turbine inlet. Here they spin your little one. The fan goes in there and then the exhaust comes out here and the rest of the exhaust goes down the tailpipe, because these fan blades, these wheels are mounted on a common shaft, when the exhaust spins the hot side, the cold side It also rotates and that sucks in air. from the atmosphere it pressurizes it and forces it into your engine, so in summary, this is how a turbo works: it uses its exhaust to spin some fans to suck in and pressurize air and force it into your engine, then here we have our discharge valve.

So the wastegate is basically the system that we use in a turbo to control boost and this one is designed to run at eight psi. So basically what happens is we're going to engage our wastegate at vacuum pressures and then when we hit eight psi of boost pressure, the spring. on this wastegate will overtake, it will force this arm to act and open and it opens a little flap here that allows the exhaust gases to bypass the turbo, effectively reducing the boost pressure or controlling the boost pressure, now that We understand how a wastegate works and what it's doing, let's go ahead and remove the turbine and compressor housings so we can get a better look at the fan blades and what the heck is going on there, okay, when we're talking about turbo wheels like this and This is our compressor wheel there are basically two sides, there is the inductor and the exductor, the inductor will always be where the air enters and the exductor will be where the air exits.

This CX Racing turbo might be ok but the fact is it doesn't have as much information, that's one of the big problems with cheaper quality parts, you don't necessarily get all the information that you get with a high quality part, so let's go ahead and measure our fan blades here. We are going to measure the inductor and the exductor, we have approximately millimeters and a half. Now let's measure the exductor side of the compressor wheel and that's where the air comes out. We have about 70 millimeters, so now let's remove the turbine casing. and take some measurements of that wheel and there's our turbine wheel and our turbine casing, so on the turbine wheel the inductor and exductor are actually opposite the compressor wheel again, it's all about where enters and where the air or exhaust gases exit. and on the turbine side it comes in through the large part of the blade and comes out through the small part of the blade, so let's measure our inductor and exductor, okay, about 65, what do you think?

Now that we have taken the measurements of our compressor and turbine wheels on the inducer and exducer side, that means we have four measurements total on both blades, but we can reduce those four measurements to two and those two measurements will characterize each of our wheels and That's what's called adjustment. You may have heard of turbo tuning before and it basically describes one of its wheels, so we'll say that our compressor wheel here describes the relationship between the inductor and the exductor, so generally speaking, the higher the setting number. more air will flow through a wheel, so now that we understand a little about our compressor and turbine wheels, how to measure them, what fitment is and what wheel size means, let's talk about the housings they sit in because they are pretty . important these are our casings this is our compressor casing and this is our turbine casing and the way they are measured is another measurement that you may have heard of when you talk about turbo stuff ar what does area over radius mean now the ar rating of a casing will basically be related to its ability to flow, we don't really pay too much attention to our compressor casings, but a turbine casing is absolutely critical to sizing the correct turbo for your engine, basically the casing measurement.

Turbine relates to how much exhaust gases can flow through it, which is very important in terms of generating power the way you want to generate power. We don't really need to know what the measurement is. What we need to know is that the higher the ar number for a casing, the more it can flow in terms of exhaust on the turbine side or to some extent in the compressor casing, but if you use a large turbine casing which will also create delay, it takes time to wind it. A smaller turbine housing will create a faster, more responsive reel. turbo, but since it can't flow as much exhaust, it can choke the engine at high revs when large amounts of exhaust try to flow through this housing, so that's kind of a trade-off, but getting it right will ensure that you have a turbo that does exactly what you want, whether it's huge peak power and you're okay with a little lag or whether it's a really responsive turbo at the cost of peak power.

Now, my preference generally speaking, especially for a street car like the old Miata, is to have a responsive turbo that's fun to drive that has good low end that doesn't necessarily make maximum top end power because that's not really where I spend the most time. part of my time on the streets, you know what I mean, okay let's talk briefly about compressor maps, it's one of the best tools to use to size a turbo for your engine, it basically gives you a clear view of how much air can a turbo flow and we need to talk about some basics real quick before looking at a compressor map.

It's all about airflow horsepower. It's all about airflow, the more air can flow through an engine the more horsepower it can make and obviously that's what turbos are for, they help us increase airflow but turbos come in all types of different sizes and come in different airflow as such, but since horsepower is all about airflow, this is how turbos can be rated in horsepower, so when purchasing a turbo, you should Make sure the manufacturer's listed displacement for the engine and the horsepower range for that turbo match your goals. here's our compressor map, so let's talk about what we're looking at here first outside of the x-axis corrected airflow in pounds per minute.

Now, generally speaking, one pound of airflow per minute can translate to about 10 crank horsepower, so here where you see 20 pounds of airflow per minute, we can think of that as about 200 horsepower. power, if you want to make 500 horsepower then you need to find a turbo that can comfortably flow 50 pounds per minute now in the miata my power goals are around 225 wheels. horsepower, that means I need to make around 270 at the crank, which means I'm looking for a turbo that can efficiently flow around 27 to 30 pounds of air per minute to meet my horsepower goals. Now the y axis is our pressure ratio.

This is kind of boost, but it's a little bit different because it's a pressure ratio, it's just the ratio of the pressure in front of the compressor, like in the atmosphere, versus on the other side of the compressor, the boost side, which is putting in air. your engine now to understand that, we have to understand that the atmosphere we're in all the time is about 14.7 psi, so in the case of the miata and the turbo that I'm going to use, we're going to start with eight pounds of boost , so that is wasted internally and we will increase it in the future, but for now we are going with eight pounds of boost, basically what we are going to do is add the boost that we are going to generate with our turbo. to atmospheric air and then the ratio is that number versus our atmospheric pressure, so that's where we're going to land on our pressure ratio, we're running a pressure ratio of 1 to 1.55 and then we can determine whether or not that puts our turbo in an efficient area, okay, so let's see where it lands with about 27 pounds of airflow per minute at about 1.55 in our pressure ratio, which leaves us right here, so basically what we're looking at here on the graph is this whole series of ovals.

These are called efficiency islands, so we want to land on these efficiency islands to make sure the turbo is running in an efficient range, if it's not it's just going to create a lot of heat and not power, so if we want to do the With the increased power, we want to make sure we land our turbo in an efficient area. We can see that we land on these islands of efficiency. I think we're now in this range of 65. This has been a very brief look at the compressor maps if you want. Go much deeper into them and learn much more about compressor maps.

You have to go see my friend Greg Peters on the Car Passion channel. He does a whole video on compressor mapping on a Turbo Miata. It's really great. All that being said, when you're actually shopping for a turbo, what you'll find is that almost every turbo manufacturer uses a totally different naming convention, so the numbers that are attached to the name of a turbo for accuracy from Garrett or Borg Warner, they're all going to be a little different, but they all kind of relate to the measurements we've talked about here today, so all you have to do is go to their spec sheet and find out what they're with.

The numbers are really related, so let's get into it. Let's start getting our hands dirty and actually ride a turbo to this nasty point. Well, it didn't take long for me to have my first setback. The first thing I wanted to do when installing the turbo was to increase the oil pressure. turbo, solve that and honestly, I went in thinking it was no big deal because one of the nice things about the 1994 mazda miata is that on the side of the block, just below the exhaust area, we have a coolant port here and a oil but of course the cx-racing kit doesn't take that port into account so I don't have anything that can connect directly there so I need to go from there to my oil feed line which is this npt thread , so hopefully I can find a pretty quiet little adapter to go from that to that, but I guess I have to do some online shopping, but for now I'm going to reconnect the turbo manifold and then work on the oil return because I know that I can get it to work, and the knocks keep coming, so we had our little problem with the oil pressure connector that I'm going to need to find, so yeahYou're a dad, it's no big deal.

We'll keep running, we'll move on to the oil return that you see with any turbo system, you need to get oil to the turbo and then you need to return it to the oil pan, so in a situation like this where we don't do that. We no longer have an oil return for a turbo. Our turbo kit, the CX racing kit, came with this little accessory. Basically the idea is to drill a hole in the side of our oil pan, then this goes in and then these two washers help it out. No leaks squeeze that from the inside and then you have to return the hose it can go from your turbo straight to this and then this just sticks to the side of the oil pan so I figured no big deal just pull the pan off of oil.

I turned it off and put this on. What I wasn't thinking about is that to remove the oil pan from a miata you have to raise the engine and lower the subframe, so I have a little more work ahead of me than I anticipated. I'm going to have to remove the oil pan to install this and there are no two ways to do it. I'm going to have to do it. I'll see you tomorrow Hello friend, I know where you are, you forgot to go. a gift for the donut fan in your life and it's also late for anything to ship, well you're in luck because Donut Media gift cards exist and you can get them in phenomenal increments.

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Now this location for the oil return will work in terms of where everything is here and my route from the turbo to the oil pan. I guess I hope that was the plan, that's why I put it in. here, but the big question is and one of the problems in my opinion with this style of return that has a nut on the inside instead of a threaded style is that now there is this big nut on the inside, so I'm going to put the oil pan. Start without any sealant and crank the engine by hand just to make sure this doesn't hit the crankshaft or the bottom of the connecting rods or anything because if it does it's a pretty big problem and I'll have to move this somewhere else.

I didn't really think about that before doing this, but hey, here we are now. The good news is that I have a backup oil pan. If I need one, everything will be fine. We just finished checking our oil return clearance and the good news is we're good uh everything will be okay. I need to make a small hole in the wind tray that drops here so it doesn't interfere with that, but it looks like this return point will. exquisite work well that means we're pretty much ready to put some sealant on this oil pan and put it back on and put the subframe on and get back to the turbo.

Okay, we have the oil return line. I finally installed it in the oil pan and it's ready to be attached, so now I'm just putting the turbo on the turbo manifold, which is great news, very exciting and then once we have it bolted to the manifold, we will connect our return. Line taking big steps baby, that was the sound of the number four piston coming out the side. The best thing about problems is discovering how to solve them. Well, sometimes putting turbo hardware in place is difficult because it leaves you in difficult places. trying to put hardware on and then trying to put a wrench on that hardware to tighten it, so like on this specific nut there, I can't put a wrench on there, so I'm just tightening it from the bottom and I'm using the screwdriver to keep it from the nut turn so this is my screwdriver wrench a very good wrench okay the turbo is tight which is great news so now that we have it in place we are ready to trim our return line of oil and connect it to the turbo, so to do this basically the most important thing to make sure is that there are no sharp turns, curves or kinks in your return line, which obviously comes into play when you choose where Place it in your oil pan. but it also comes into play when you're routing the hose, so I've got it going down through the lower coolant hose and a couple other things down here and honestly it looks pretty cool, it's a nice straight shot to the nipple going down for the oil. pan, so now I'm just going to trim it so we have a nice straight return line.

Okay, another thing you want to make sure of when you're setting up your turbo and all your lines is the oil feed and especially the oil return. Keep it fairly vertical in terms of its orientation so you can turn the hub that houses the rotating assembly any way you want, but if you turn it too much either way it will be difficult to drain the oil and that's not the case. What you want if your turbo is having a hard time draining oil or the oil is getting clogged it will start to leak out the seals will start to smoke and it just won't be a good time so you want to make sure the oil drain is pretty close to the vertical.

I think they say 15 degrees in either direction is fine, but I just try to keep it straight up and down so the turbo is in place and our oil return line looks good and is connected well, so now I think which is time to see if this Downpipe adjustments, we talked about it last week but now with the turbo in place we can install it so let's see how it goes well that's good news I mean hey now it's in the right ballpark, so these are v-band clamps. They're cool, uh, exhaust joints, I guess you could call them, so we just use this little clamp to get the downpipe roughly in place.

The good news is that it seems to fit pretty well, that's where it belongs, uh, it's pretty. close to some things like our coolant line to the heater core, we have a little air gap now, but that being said, this downpipe is going to be super hot and it really should and eventually I'll put an exhaust wrap on it to try to contain some This heat is the same with the turbo manifold, it's not a bad idea to wrap the exhaust to try to contain the heat, you know, keep it in your turbo instead of the engine bay, but for now I think everything will be fine . ready to go underneath and see if this fits, so this is the mid pipe that goes from the downpipe to our stock exhaust, yeah, pretty close, it's got a little flex pipe here, this is going to be good, very good, this is great.

I just need to put the V-band clamp on here, get some nuts on this end and wow, the hot side is done, the turbo manifold is attached and now we have a downpipe and mid pipe that connect to the exhaust. it's going all the way back it's really taking shape so we put a turbo on this miata and that's awesome but before we go let's talk about something else one of my favorite combinations of words in the English language and in a set. of words that came to mind because I forgot to mention the shaft play above, so depending on whether or not you have a journal bearing turbo or a ball bearing turbo will dictate how the shaft play should feel like this which, first of all, you have I have the up and down axle play or the radial axle play, so you try to move it up and down and it's in its little house there and then there's end play or axial play, like this I try to push the shaft this way instead of this.

So, because this shaft rides on a thin film of oil, there will always be some up and down play in the shaft of a journal bearing turbo. This is new and you can feel a little play now, that's totally normal. when the engine is running there is oil pressure which stiffens that pup, the only problem is you can't really get your hand in there to move it when it's running, if this was a ball bearing turbo and there was both up and running down that would be a problem, a ball bearing turbo all the time should have very little up and down play, now what you really want to pay attention to in a ball bearing turbo and a ball bearing turbo is the end game, so if you can move the axle in and out like this you have a problem, fortunately we can't, so that's what you're looking for when you talk about axle play, there's up and down and there's an end to another one, so now that I've gotten away with saying heck game on YouTube a few times I think that'll really do it for this week and what a week it's been, there's finally a damn turbo in the miata.

I know you guys have been excited for this day and so have I and finally here we have the engine compression tested and leak tested, we did the manifold, we did the turbo and now the downpipe is on too so next week you'll have to check it again because we're going into the cold side. I'm going to be doing all the intercooler piping, the intercooler itself, and the wastegate, so don't forget to follow me on Zac Job and follow Donut Donut Media and I'll see you here next week for some wastegate noises, Which does not. I can't say that because we won't have noise next week either.

What no, that doesn't work, don't use it, no.