Turbo Education Thread

[v8s_are_slow]

Back in the old days (around 1997), I didn't hear much talking about things like "x" a/r, garret, hybrid, mitsu, ball bearings, etc. It use to be people just upgarding to 14b's, 16g's, 20g's, etc. Now there so much talk about this and that that I've had a hard time following. Mainly because I've only had one type of turbo for so long. And lately, I've just searched threads to see what people go with as far as a turbo for "x" setup and try to see what works best for them (as I'm sure many others do). But screw all that. I wanna be educated and know for myself.

Can you guys with the turbo knowledge please break down some of the terms and help me (and others) decipher some of what I need to know?

Things such as the difference between a mitsu, garret, etc.
Meanings of .63, . 70 a/r, etc.
Reason you'd want or NOT want to port the turbine inlet or outlet? Or both?
Can someone tell me what a 67 mm inducer is? Or any other size?
What's the difference between a 50, 60 trim, etc.?
What's a 360 degree center thrust bearing?
And so much more I'm not even listing.

When looking at a website such as Slowboy, some of the turbo's have different options and I have no clue why I'd wanna get this or that, and maybe not something else.

There's so much out there I don't know where to begin? And when discussing turbo's, I see so many people bickering that it makes it hard for me to be able to decide for myself. Hoping many of you turbo wisemen can help out and post your knowledge. Thank you!

Scott

[leet]

Not a bad idea.

I'm going to sticky this in hopes of getting some useful information in here.

[v8s_are_slow]

Hoping maybe some or at least one vendor would chime in as well. Heck, they know about their turbo's that they're selling. Would think they'd be the best one's to ask. Also would help if they didn't have to explain to every customer who calls (which takes time out of doing other things at work that probably needs to get done) if people could just educate themselves and just have to place an order.

[ISUJakey]

If anyone can get access to the Talon Digest, there is a great, multi-page, explanation of turbos that I printed off a couple of years ago. Unfortunately, I can not seem to find access to the Talon Digest anymore to provide a link to the information.

[Defiant]

Originally Posted by ISUJakey

If anyone can get access to the Talon Digest,

Anyone can.
http://www.me.mtu.edu/~edan/talon/

[v8s_are_slow]

Come on people, step up to the plate here. I'm always seeing people trying to argue their knowledge and all. Yet no one's trying to help out in this thread for everyone else's sake in tuner land? Just answer whatcha know if nothing else. Don't have to answer every single question.

Defiant, by chance know which one of those in there is about the turbo's? That's a heck of a lotta links to go reading thru to have to find.

Appreciate anyone who will take the time to help out in this thread.

[sleestack]

I'll step up to the plate, but this is going to take a couple of days to write in order to cover this proper. Might take two or three pages and several illustrations, problem is most people have a 3-5 line attention span on message boards. In addition, 2 or 3 of those questions have been covered in depth in various places on the internet.

[v8s_are_slow]

Originally Posted by sleestack

I'll step up to the plate, but this is going to take a couple of days to write in order to cover this proper. Might take two or three pages and several illustrations, problem is most people have a 3-5 line attention span on message boards. In addition, 2 or 3 of those questions have been covered in depth in various places on the internet.

For those willing to learn, the attention span would endure 2-3 pages. And for those not all that interested, still better to have the info posted than not. I know I've searched for some info but always find the threads where people start griping that they're right. Back and forth. Or just the threads saying, this turbo is better...this wheel is great on it. And then return reply, that turbo is ancient technology. That's pretty much what I see when searching. Any info I see is hard to tell if it's fact or opinion. Any of the various places you're speaking of, I'm not aware of but I'd appreciate ya pointing me in the right direction Thanks!

Guess i'll add more questions that I'm wondering about...

What's the difference between a T3 and a T4 or a T3/T4?
What's a 270 and a 360 standard thrust?

Um, that's all I've got for now.

[Mark90gst]

Hey guys hows it going. I'm going to step up to the plate. My spelling is not the best but here goes.


The whole garret turbo explanations. First the different in the bearings as you stated was, what is a 270 or 360 race bearing or ball bearings?


Well inside of the center section of a turbo there are bronze bushings that the turbo shaft spins extremely fast with oil. In older and more common the bearings are 270 degrees they are not a full round bearing which can make shaft play more commom in turbos. In some of the newer turbos like say the precision 60-1 you can get a with 260 bearing which are completely a full circle allowing for longer lasting and faster spooling turbos. Next we have dual ball bearings which are found in turbos like the gt35r and gt30r as examples. Theses turbos have real ball bearing where the tolerances and perfect and deliever great spool time. I mean good. So there is the major differences in the turbo center section bearing types.


next question is what is a trim as many guys talk about around here.

Many garret turbos are sized in trim. Trim is nothing special expect a big math calculation of the inducer/exducer times and divided by more numbers that the average person will not have to worry about in there life time. As you read about these turbos usually a 60 trim is bigger than a 50 trim. A 50 trim TO4B will get you to that 400 hp mark or can you handle the 60 trim which pushes enough air to support the big number on the dyno. But can you handle or do you want bigger?

Next you ask why to port a turbo inlet out let both?

well here goes a shot at what I think. well on the exhaust housing of a turbo you need a certain amount of exhaust gas pressure to make your turbo spin fast enough to create boost which we all love so much. So us power driven peopletake our turbos apart and start to port them to get more exhaust gas in the inlet of that turbo to make it spin sooner because you are putting more gas in that area of that turbo. Then people port the outlet of the turbo to get that extra gas back out and into your big 3.0 inch exhaust I HOPE U Have. well next many people port the wastgate outlet to get the bypassed air out to your exhaust and not to spin that exhaust wheel any faster at high rpms and that right there explains the 16g boost creep, but why would you put a big bolt on, on or a garret on with out a nice shiny tail 38 or 44? now that makes sense in my would and I now money is the problem with many people. I now we dont have any.

Next you state what is a T3 turbo or t3/t4 or a straight monster t4?

Well a t3 garret turbo has been around for many many years. it can be found on a 84-86 Nissan 300zx with a .63a/r or even older saab turbos. A t/3 means the compressor size of the turbo.Most I say most t3 are too small for our cars. That is why you see many people running t3/t4 hybrids which combine a t3 exhaust housing which a big t4 compressor housing to flow some serious air to feed our monster motors we are trying build. a straight t4 usually a monster exhaust housing in lam-mans terms which are used on Supras and some DSM but they require more exhaust gas pressure to spin and 90 percent of us dont have this much gas to blow out on these things.

Next maybe one of the most important things is choosing a turbo which I'm only going to touch briefly on because my hands are getting very tried by now and no I'm not the best typer in the world, and I sit here looking at my DSM in the drive way and want to go get on that 60-1 that lurks under the hood of that beast.

This is where the whole A/R comes in to play and the amount of air a turbo can make, the surge limit of the turbo, make boost, flow charts and all of the other good things that us DSM fans need to now about. So hear goes my best shot at this and I wont get to complicated. Where first we look at the 14b stock for most an upgrade for other. Yes it does 20pounds of amazing boost, and the exhaust housing cracks due to the heat that is trapped due to the internal waste gate design. It has a 06 exhaust housing which means the exhaust size, while the more common upgrade is the 16g which flows alot more air will push over 20psi of oh so loving boost. But you have to remember that the for the most apart that the exhaust housing and the intake side of the turbo are in haromy. By which I mean is the the turbo pushes a certain amount of air into the motor and the exhaust housing is the right size to flow the exhaust gas back out. That is way a b16g have a 7cm exhaust housing, just porting a 6cm exhausting wont flow as much as a 6cm. Think of it as funnel. put more and more water in it but you only get so much out. Increase that bottom hole size and now the funnel breathes which means your motor can breath now.
Part 1 is over I need to go get food I will continue with this in a minute or so.
so just be patient it coming

[Mark90gst]

class is back in session and I grabbed a soda and downed a few tacos, looked under the hood my car and checked out that precision turbo down under that tubular manifold. Back on the topic now.



where we yes I had something to say, hey V8's are slow man, not all v8's are slow just remember that. My buddy has a TT chelleve that both of us build. it a v8 and it scares the pants off me. When the car hooks shut up and hold on. But anyways that has turbos that we love so back to the 16g and The garret turbo discussion that we want to read about. Now that we made 300 whp on a 16g with a few mods, some people make more dont get me wrong, some people try the 20g, bigger badder TD06 compressor housing bigger exhaust housing flows some serious air pretty close to the common bolt on 50trim. with that 20g some good and bad power can be made. But people like to say why? why by a 20g why buy a 50 trim. People say why. Well I have been through these turbos and watch them all dyno numbers of times and I can tell you what they make for power. If your at the 20g mark and want to upgrade You might want to start to consider a new


Turbo 20g plus
External waste gate setup 38 or bigger
2g manifold ported is nice
nice o2 housing
and a intake we problay a 3 inch inlet
and new feed and return lines, stainless

now not all the parts above are needed but I suggest them and you ask why. I say this because I have been there done that and it broke so I spent the money and did it right the second time, not the first like I want everyone to read this to due. Do it right the first time and have fun with your new turbo and not have to fix it every day. Now that the Mitshu turbo is out of your mind and you want a big bolt of series turbo you see .63 a/r or .83 a/r Dont get scared. never be scared this is just another way of sizing the exhaust housing in garret term think for a second


Mitshi Terms
Small B I G
6cm 13cm

Garret terms
small BIG
.43a/r 1.15 a/r (What the TT chevelle has) Ha Ha

now for the most of us we fall in the middle or this category
like the .63 a/r class. For example my precison has a .63 a/r and it is a 60trim. It has alright spool time and the turbo huffs some good air. Now you think I want to flow alot of air, but wait you also want a good spool up time. you always need to give a little to get a little in life we cant have the best of all the worlds. But wait they invented dual ball bearing garret turbos. Yes there big, yes they flow alot and the spool is good. That is why you can take a GT35R with a .83 a/r exhaust housing and have it spool pretty good even the the a/r is so high. But most of us dont have the money for a 35r, at least I dont so I deal with the lag. It is okay.
there is so much more I want to write about like clipping the turbo wheels and ceramic blades and how the turbos work in newer FORD yes I said FORD turcks. Didn't you hear hear. The ford truck turbos are amazing Oh u dont know. Well on your way to work do me a favor one favor I ask of all you people of read this article that took me hours to write and I promise there is more to come.

Just do this when you see a new FORD diesel truck roll down your window and listen, then due the same to a Cummins diesel and listen. And write back to me. and tell me what you hear.
Thanks for reading, and if people want more write in and say you want to hear from me.

Mark

[v8s_are_slow]

Sure everyone appreciates the info. But now for another question....

Let's take a turbo from here. I'll just pick one. Take a look at this one.

http://www.extremepsi.com/store/cust...cat=508&page=1

Okay now how would you go about selecting the right compressor housing, exhaust housing, and the trim you want to use to get a balanced setup? Is this an educated guess, flip a coin, or maybe just ask them for the flow rates that maybe they've already tried out with different setups applied? I know people have different goals and different engines. Many things can make the spool time and power vary. Things such as the engine you have (2.0, 2.1 destroked, 2.3 stroker, 2.4 stroker, etc.), the compression ratio, whether you have an aftermarket sheetmetal intake, the cams you have, size of the i/c pipes, size of the intercooler, etc. etc. etc.

But how would one go about trying to get the perfect match for a "x" setup? And in means other than just asking for opinions here on the forums being that everyone seems to have a different opinion as to which turbo is best. Myself for example, I'm having to read TONS of threads on lots of different turbos, ask spool times, what people are making for power, 1/4 mile times, etc. and trying to make the best decision off that. Not sure if it's the best way but that's where I'm at at the moment as far as how I'm making my decision for what I want...at the moment anyway. Can't speak for others.

Hope this thread keeps going and more useful info coming

[sleestack]

Yikes! It's hard to answer these questions when answers take so long to write all the while more questions are getting shot out so fast and so general. So please be patient with the questions while I hammer these out, I will try to answer one per night for the next week.

[sleestack]

Simply put, Mitsu is to Garrett as Ford is to Chevy, at least in the DSM market anyway. Mitsubishi is an extremely diverse company that manufactures everything from commercial power plants to televisions. In order to simplify supply concerns and control costs they make several of the components that make up the products they sell. So they manufacture specifically sized turbochargers for their automotive sister company. For example, Mitsubishi Engine manufactures the TDO5 14Bs for the 90-94 Mitsubishi Eclipse.

Garrett, on the other hand, makes a universal line of turbochargers designed for a generic operating range of horsepower. They don’t exclusively make a single turbo for any specific engine on a large scale. If contracted to supply a turbocharger for an OEM, they’re solution is usually a selection from there diverse portfolio of turbos. Garrett offers a greater range of compressor wheel offerings that far surpass the flow capacities of the largest Mitsu compressor wheels.

There are exceptions to this of course , but to keep this primer concentrated and to the point as possible I won’t go into details on every manufactures entire product line. But for a quick example, Greddy (Trust) contracts Mitsubishi to make generic (T78, T88) turbochargers for it’s own line of proprietary turbochargers for the aftermarket.

In the beginning of DSM performance modding, Garrett turbos with their square flanged turbine inlets didn’t easily bolt on to DSM engines with round flanged manifolds without complex adaptor plates or custom-made, expensive, hand-built headers. Efforts in performance gains started in modifying the stock turbos within Mitsu’s offerings.

Mitsubishi makes hundreds of combinations of turbos for hundreds of applications so it has always been possible to interchange individual components in these turbos, between platforms, to increase the performance of a turbocharger. For example, taking the stock 14b compressor out of the stock 1st gen turbo and replacing it with the factory upgrade 20g compressor wheel and housing from a Cyclone/Typhoon turbo, then clipping the turbine wheel and throwing in the larger 7cm turbine housing from a JDM Galant VR-4 makes a Buschur Racing spec 20g (the tried and true “ole school” bench mark in DSM performance). Larger turbine wheels were soon discovered in the Fuso delivery truck power plant program. These larger turbine wheels made it possible to upgrade the compressor past the size of a 20g compressor wheel and actually see benefits. This is where the “hybrid” turbo entered the spotlight.

Mitsu compressor wheels cap in size after the 20g wheel, with the exception of the hard to find and costly 25g. It was necessary to think outside the box for the greater good . That is where Robert Young (then a turbo rebuilder for Turbochargers.com, now owner of Forced Performance) came up with the idea to put the more diverse Garrett line of TO4E compressor wheels in the Mitsu housings with minor modifications. When used in conjunction with the larger TDO6 and 6h turbine wheels found in the FUSO truck apps, these Garrett compressor wheels opened new doors for DSM aftermarket performance. This new line of turbos was deemed the “Frank” series of turbos. Several combinations of turbos where standardized as Frank 1, 2, 3, 4, 5 and later 6. Each Frank turbo combination had it’s pros and cons (some more than others). It was then thought to simplify the series into one smaller more responsive turbo for mostly street use (Green) and one larger street/strip turbo that could really dish out the horsepower (Red). There have since been other variants on the hybrid idea by several different companies. Now some of the more popular ideas on the hybrid idea involve casting a new turbine housing that bolts a complete Garrett CHRA (cartridge) into a housing that bolts right up to the DSM 60mm round flange manifold. For example, the FP30 series of turbos have a custom-cast 304SS racing volute housing that plugs the latest generation of Garrett Ballistics Concepts GT Ball-Bearing turbos that bolt right to a ported EVO or 2nd gen manifold.

It has become more and more popular in recent years to have a custom tubular manifold made that can bolt a straight Garrett turbo to the DSM cylinder head. When properly made with equal-length runners and correct phasing these headers allow an increase in performance with the versatility of being able to use a straight Garrett turbo. The only downfall is the additional costs involved in the custom fabrication of the header and the O2 housing since these have flanges specific to the Garrett T3 and T4 turbine housings.

So in conclusion, the main, most important differences between the Garrett and Mitsu turbos are the turbine inlet and outlet flanges and the greater compressor wheel variety and capacity in the Garrett turbos. Stay tuned...

[BREW]

HOLY ZOMBIE! That's the kind of information that should be required reading for anyone who seeks information about any turbo past, present, or future. I'm surely not the most educated man on turbochargers but I also feel like I have gained enough information over the years to say i'm not a newbie. After reading that post (sleestack) I've come to the realization that I'm not even close to knowing all there is to know regarding the subject. Sometimes it feels good to be stupid . Anxiously awaiting part II. Excellent information.

Thanks again,

Brew

[sleestack]

Here is a big one, I am going to let a big secret (for some) out of the bag here for you guys so bear with me through this.

First of all, know that there are compressor housing A/R’s and turbine housing A/R’s. Since turbine housing A/R is likely the context of your question I will address that here.

A/R ratio is a term we use in the industry to differentiate flow capacities between like housings with similar exterior dimensions with different size volutes. What is a volute? A volute is the spiral shaped cone on the inside diameter of the turbine housing that begins right about the point in the housing where you can no longer see into it, after the inside diameter changes from the shape of the flange opening to the shape of the volute (usually a teardrop shape). The volutes job is to harness the energy (heat, pressure, velocity and sound) from your motor and concentrate it onto the turbine wheel to generate power to turn the compressor wheel. The number designation given is a ratio derived by taking the cross-section area of the beginning of the volute over the distance from the middle of the cross-section to the center of the turbine wheel (axis).



So what does this number tell you about flow? By itself, …nothing. This number is used to compare housings of similar castings with the only difference being the volute. Here is where I am going with this. Say you have a housing whose area is 1.45 in2 over a radius of 1.69 inches, that makes the A/R= .85. Well, say you have another housing whose area is 1.8 in2 over a 2.1 inches radius. Well, the A/R is still .85 so that means they flow the same …right? WRONG! So what does that tell us? You cannot compare turbine housings between families just by the A/R. Reason I go into this is that I have people ask me all the time what the A/R of a FP30 housing is. Why? There is only one FP30 volute, so how is knowing what it’s A/R is relevant? You can however compare the A/R between all T31 housings, or all T4 housing, etc.

The shape of the volute can affect the way the potential energy is harnessed. The closer to the shape of a teardrop the volute takes, the easier energy is transferred around the housing and into the turbine wheel. Most OEM castings like the 7cm Mitsu housings have a compromised volute (teardrop cut in half) for water line clearance to the bearing housing and ease of casting. On the other hand, most aftermarket housings like the FP30 and Garrett T31 housings have a better shaped volute patterned after Garrett Motorsports housings for maximum efficiency.



Here is where A/R comes in to play. Say you are buying a straight Garrett 50 trim with a Stage III turbine wheel. When it comes to the turbine housing you have 3 popular choices. You have a .49, .63, and .82. They all have very similar exterior dimensions and look exactly alike but on the inside they are very different.

NOTE: The following scenarios include hypothetical spool times and performance numbers used to illustrate the difference between turbine housing sizes and may not necessarily reflect the performance characteristics of this specific combination on your car exactly.

The .49 has the smallest volute so it will make our turbo respond fast, with the least amount of lag of the 3 choices. This small volute makes it spool fast but once the turbo is spooled and the wastegate is open, this small volute now becomes a restriction to the flow of exhaust gas speeding out of the manifold looking for freedom to the atmosphere. Backpressure (pressure that builds in the manifold before the turbos turbine) builds to 63psi before the turbine and less and less exhausted air/fuel mixture is allowed to exit the combustion chamber which limits your horsepower. You reach 20psi of boost by 3400rpm but because of your diluted A/F mixture in the cylinders you reach 345 hp by 5700rpm at 20psi. This makes a great autocross turbo because you make plenty of power down low with enough torque at the bottom of third gear in turn 4 to pick up half a second lap time.

Say you decide to go with the .63 turbine housing. Instead of 63psi of backpressure you only get 33psi. This allows a cleaner charge in the combustion chamber. A lot less backpressure builds in the manifold and as a result you make much more power on top, as much as 360hp by 5700rpm. The penalty is that instead of reaching 20psi of boost by 3400rpm, you don’t see 20psi till 3700. This can be a much better compromise for a car driven on the street that sees occasional duty at the local drag strip.

All out setups that demand every ounce of performance from their turbocharger require the largest A/R they can tolerate within reason. The .82 housing offers the least restriction to flow of the three. You may not see 20psi till 4000, but you’ll be able to hit 380hp on pump at that boost. Backpressure is kept in the high 20’s.

Restriction varies with mod level. Guys with fewer mods that affect VE are less affected by the restriction a smaller housing. So, for a guy with a stock motor with basic upgrades a .49 housing might be nice. By the time you add heavy cams, port the head, install a sheet metal intake many, etc. even a .63 A/R housing might be out of the question. Conversely, a guy with a stock motor might not see any better backpressure readings with a .82 than with a .63, now all he has is a lazy car. For help on where you should start, share your data with friends that have similar setup’s that have backpressure data, or get the advice of an experienced turbo professional.

Most people never know what their back pressure is. I mean how many of us really have a pressure transducer tapped in their manifold? I’ll tell you, I see it without fail. All these guys have that ridiculous EGT gauge tapped religiously in their #1 runner. I honestly think only the Autometer blinky light A/F meter for a narrow band OEM O2 sensor a more worthless piece of shit gauge to occupy gauge space, but I digress. You don’t have to have a gauge permanently mounted in sight for backpressure. Only need to make this measurement after you make a change that affects your engine VE. VE is volumetric efficiency. VE is a measure of your engines ability to move air through it. Head porting, camshafts, intake manifolds, air filters, intercoolers, turbos and exhaust systems all affect your engines VE. Examples of modifications that don’t affect your VE are fuel injectors, piggyback ECU controllers, blow-off valves, fuel pressure regulators, fuel pumps, and MSD ignitions. You also don’t have to have a fancy stand-alone ECU with an expensive 5 bar MAP to take backpressure measurements. Next time you are in AutoZone, take a look in the hillbilly section. Next to the chrome naked girl silhouette mud flaps you’ll find cheap oil pressure gauges. Pull that stupid EGT probe out temporarily and run some copper tubing to the hole with a 1/8 NPT compression fitting. Run enough tubing to protect the gauge from the heat of the exhaust manifold. Then run rubber tubing to a generic fuel filter assembly, then run more tubing to the cockpit to that bitchin oil pressure gauge. The fuel filter acts as a dampener to reduce the pressure oscillations from the exhaust “putts” and allow you to make a cleaner measurement. Get a friend to ride with you to watch the gauge. The gauge may not even flinch till you hit boost, but then should rise quickly with boost and continue climbing with RPM till you reach your engines max VE point then taper off (usually around 5700 with a stock intake manifold).

So now that you have your backpressure reading how much is too much? Generally speaking, you don’t want more than a 1:1.5 ratio of boost to backpressure. So if you’re at 20psi of boost you should not see more than 30-35psi of backpressure. If you do then you should upgrade the turbine side, you’ll make more horsepower for every pound of boost you run.

Turbine wheels and exhaust system diameters can also affect your backpressure reading, but to stay on topic I will address turbine wheels and pipes later on. For the most part, turbine wheels being part of the CHRA, are not easily changed by the average do-it-yourself tuner. For now, just know that if you upgrade your housing and your backpressure reading doesn’t come down where it should, your problem might be your turbine wheel. If this is the case or if larger turbine housings are not available you might consider a complete turbo change.

Stay tuned…

[paingod5150]

Thanks for the information.

This makes a LOT more sence now.