Turbo Selection

[Chezedik]

I have spent the last three days looking at flow maps, after deciding that supercharging may be the dream of someone with a ton of money to throw at the problem. I have come to the conclusion that I would like to use a MHI turbo for a few reasons, mainly cost efficiency, availability, internal wastegate, and the readily accessible maps (probably not worth buying a turbo, if you can't find a map). Anyway, I have a KA24DE with little going on internally other than 2 248 cams and a slight bump in compression from having to shave the head to surface it (.009"), also the head has been port matched to the intake/header. I have decided between a few turbos, but cannot find anyone using some of them with any reasonable experience. So I would like to know, what kind of turbos are you using and at what boost level, what is your setup? Please help me figure out what I will be able to do safely. I am thinking I will try to run at about 6-8lbs using a 12:1 FMU, and backing off timing 5 degrees or so. I would like to do this with an TD05-16G-7m (8lbs) or the TD06-17c from the GMC Syclone (6lbs). I will have a full exhaust and test pipe, Jacob's ICE Pak, Bored TB, no SCV, etc. I also have a fuel press reg, can I run it with the FMU? I have also done the math on what unrestricted capacity of the motor would be, and I think either of these will be good options. I would appreciate anything you guys can help me with.

[WDRacing]

Read this and check out the members web pages, there is alot of good info here. Any other questions can be readily answered by a simple search through the forum.

zerothread?id=99647

[Chezedik]

Do you know if and MAF equation exists in any of your material

[WDRacing]

I don't know of any equation...I think your making this WAY harder then it needs to be.

Answer yourself these few questions.1. What am I using the car for?2. If you do race is it more drag or road course?3. Whats your budget look like?4. How much power are you looking for as a max?

Those questions alone will tell you exactly what turbo to buy. Or atleast help us to explain why you should buy a certian turbo.

WD

[Chezedik]

1. Street and road course2.road course, very little drag3. junkyard turbo budget, say 1K4. max 250 hp, want something in the 230-240hp range after my bolt ons

[chad_KAT]

well for about 2500 you could get the BD's stage 1 with a 12:1 FMU, boost gauge and a ffew other little componets..but if you want to use weird turbos or off the wall equipment then i hope it all works well...

[hannibal]

Check out the threads about using a T25 from an SR20 (mustangs_suck just dynoed his). Also consider the T3 turbo from a Z31 (84-88 300ZX).

Those turbos should help you reach your goal.

[hysteria]

a tiny straight t3 like mine will give you some great response, but i don't expect this turbo to last me very long. it is always spinning like crazy... like you have to accelerate very slowly in order to not get any response from the turbo... as a consequence of the turbo spinning all the time i get TERRIBLE gas mileage, so make sure you keep that in mind while making these upgrades... a turbo that takes just a little more than mine to spool would probably be perfect for you (would be perfect for me for sure, but for the time being i can deal with this...) because you do pretty much the same stuff as me.

[Chezedik]

Well, I can't find any turbine efficiency data for the MHI turbos, just the Compressor data. But, when you do the math and factor in for low boost, you spend a lot more time in the map on the TD05-16G (either big or small), than you do in the T3 super 60, like I was told was the common choice. A few things, just because Garrett does not make it does not mean that the TD05-16G is a wierdo turbo, check and see who's turbos Greddy uses. Here is a hint: M-H-Freaking I! It may be off the shelf, but it is not wierd. So, as near as I can find it is a 7cm2, which from what I can find is about like .50 A/R. So, imagine your t3 with off idle boost, or you could swap to the 9cm2 get some better top end. I want a setup that will work until about 6K and pretty quick boost response, I would say for my purposes this is better than a T3. I am sorry for that outburst, but I did that to point out that I was asking for advice not insults. So, I would be happy to take any info. Thank you.

[WDRacing]

Wanna tell me who insulted you?

If your budget is $1000, then how do you plan to build anything when a new turbo is atleast $500.

Wanna buy a TD series turbo, go ahead, wanna buy a IHI or MHI go ahead.

There isn't much info to be had for turbine efficiency as far as maps go.

Best of luck with the kit. $1000 is gonna go quick...

[DRIFTEADOR]

its not a common turbo to use (hence the weird comment) so there isnt as much information about it like there is for garret turbos. go try it out and post the results so the next guy that comes around asking the same question can have some feedback. that said, i think a 16g is way too small for a 2.4l. if i'm not mistaken thats the turbo greddy uses for their civic single cam kits (1.6l) which is already, imo, undersized.

[Chezedik]

Well, and that is why I am here asking, because I took the time to graph out what engine demands would be at 4,6,7,8 lbs of boost and found that at 7 and 8 lbs it was right in the sweet spot of efficiency when I plotted it on the map, but I am wondering if I did that right. I mean you guys have the experience with this stuff, so a jedi in training am I, and you guys are a bunch of Yodas. Of course, I also made the assumption of 80% VE, because I figured it would be better to be short than over, because I could still turn up the boost. If anyone has any better info, than I will remap it. But when I placed the same data on the map for the t3 "super 60", I found that I was in choke at 6 or 7K RPM, which I know is a bit high, but I want to be able to roll to red. Of course, I also know that the T3 is supposed to be quite a bit less restrictive, so that is something to think about too. Like I say, that is why I am here. If anyone knows of a good photo hosting site (for free) I will post my results.

[DRIFTEADOR]

i use photobucket.com

frankly I dont decide what turbo to use based on formulas. call me lazy but i dont think i need to reinvent the wheel when the info is already out there. i'm going for ~350/350 so i'll use the proven 50 trim t3/t4. btw, i think you're going about this the wrong way. instead of deciding on a turbo based on what psi you're going to run it at, you should base it on power goals

[WDRacing]

NICO has free image hosting...just check out the sticky....

[Chezedik]

Drift, normally I would say you would be correct, but my reasoning for deciding based on boost is that I have heard horror stories of the KA24DE breaking it's pistons apart due to detonation, so as I understand it, without a tear-down and expensive rebuild it is not a good idea to break the 7psi barrier, and that is pushing it. So, that is why I have picked that . I have just rebuilt mine for a re-ring, and I do not want to have to get inside it again until after college. For this, I am willing to accept a lower horsepower output in exhange for quick spool and not having to worry about rebuilding or detonation. Keep in mind, with my recent headwork, the head just got .009" shorter. Now, I know on some professional kits they run t3/t4s with higher boost, but my thinking is for my goals it is just too big and by the time I spooled up to my nominal amount of boost to achieve the proper mass, I would be shifting again. So I will take 220 at the crank to have boost consistantly. Maybe later I will switch to a better kit if I feel the need, but I am trying to do it junkyard style for the fact that I may well blow up my motor anyway. We will have to see.

[WDRacing]

Your last post was all incorrect information...

[Chezedik]

Well then, correct me. What did I say that was wrong, that is why I am asking.

[WDRacing]

I don't mean to be a d!ck, but your entire understanding of the KA on boost, any motor on boost is incorrect. Detonation will kill any motor, forged or not. You really need to read around a bit.

Your theory on boost building to slowly and as your reaching your "proper mass" you'll need to shift again...I don't even know where you got that one.

The stock pistons fail at 400WHP without detonation.

The Rods fail at 500whp or so, without over revving them.

The turbo has alot less to do with detonation then does fuel and timing.

Just ask yourself how much HP you want. Then get a turbo that will support that much. Thats it...pretty easy...

Read up on fuel management and timing control before you add any boost to your motor.

[Chezedik]

I understand the detonation will kill any motor, but I was just suggesting that I have heard horror stories about the KA and Nissan engines in particular breaking apart at the ringlands because of the pressure die casting process. I agree that it will have a lot to do with timing and fuel, but what would you suggest is the effective limit of the KA in terms of boost (reliable). I get back to this part because if I am going to have to make some serious boost to make my power, then I need to factor that into my plan. So, let me put this another way, what kind of outputs have others seen when they stuck to the stock block, and assuming other mods. Also, as far as engine management, I was thinking of getting my chip burned for larger injectors but not doing anything with the timing, or using an FMU. But if more is needed than I am here to learn. If it comes down to it, then I will just give up on the temp boost idea, and just go balls out, buy a spare motor and build it. I was just hoping to get a little boost. I would assume a lot of you guys have done this though on stock internals and relatively unsophisticated management. So, let me hear you stories. How do you do it.

[Chezedik]

By the way here is the "small"16g when graphed for the KA will be back for the T3 "super 60".http://i6.photobucket.com/albu...a.gif

[:: orion ::]

AAAhhhh....I can see where the confusion is coming from...you're graphing it all wrong.

The graph at a specific boost should be HORIZONTAL.

i.e. is should rise form the bottom left corner up to a point where you hit full boost.

So let's say you're graphing ~14.5psi, or a PR of ~2.

Assuming that full boost is reached at "0.15"...you'd graph from the coordinates"0,0" up to where a 2 PR and 0.15 meet. Then you graph over tot he right, along a horizontal plane, until you reach the airflow point at which the KA will be at redline and 14.5psi.

See what I mean?

- Brian

[:: orion ::]

Or just see this thread:

zerothread?id=59168

[DRIFTEADOR]

yep, that'll do it. full boost should be constant to redline once it's reached (provided the turbo can flow enough air). from your graph it looks as if it raises drops, raises drops again as rpm rise

[silencer.1]

AAAhhhh....I can see where the confusion is coming from...you're graphing it all wrong.

The graph at a specific boost should be HORIZONTAL.

i.e. is should rise form the bottom left corner up to a point where you hit full boost.

So let's say you're graphing ~14.5psi, or a PR of ~2.

Assuming that full boost is reached at "0.15"...you'd graph from the coordinates"0,0" up to where a 2 PR and 0.15 meet. Then you graph over tot he right, along a horizontal plane, until you reach the airflow point at which the KA will be at redline and 14.5psi.

See what I mean?

- Brian

That would be true if he were graphing for a specific psi, but he isn't. That graph is for a full range of boost levels. Each one of those lines represents 1000rpm and how much air it would flow at a specific boost pressure. According to his graph, the turbo he wants to use will boost from 5psi all the way to 19psi. I wouldn't count on it hitting full boost before 3000rpm at anything over 10psi so it should work for what he wants to do.

Here is a good site for referenceing those Mitsubishi turbos:

http://www.stealth316.com/2-3s-compflowmaps.htm

[fiznat]

...but what would you suggest is the effective limit of the KA in terms of boost (reliable). I get back to this part because if I am going to have to make some serious boost to make my power, then I need to factor that into my plan. So, let me put this another way, what kind of outputs have others seen when they stuck to the stock block, and assuming other mods. Also, as far as engine management, I was thinking of getting my chip burned for larger injectors but not doing anything with the timing, or using an FMU.

The stock KA block has been shown to handle more than 1 bar of boost without problems (14.7 psi +), but in all honesty if you want something that will be reliable I would personally stick to 10psi or under. ...And this is assuming all your tuning is there.

You say you are looking to make what? 250 rwhp? You dont need "serious boost" for that kind of power. 10 psi-ish should get you well within that range or more, again assuming your tuning is there.

Why would you get a chip burned and not do anything with timing? I dont understand that, timing is pretty much THE most important part of tuning. Power rises and falls, EGTs go up and down with just a few degrees of timing here and there. To do this right, you HAVE to have correct timing- not only for saftey, but for maximum power. ...At any boost level.

As far as picking out the right turbo for your application, I think you are on the right track. I dont see why you decided to graph out the compressor maps the way you did, but there is some logic to them. Definitely check out the stickied thread with all the other compressor maps people have already completed and posted for you to see. 10 psi is a very common pressure range, you should have no problem finding turbos already graphed out for that range along with pros + cons. Keep in mind though that these compressor maps that we draw are VERY rough approximations of real world conditions. Volumetric efficiency is not static, and it differs not only between engines of the same type, but along the RPM range as well. Dont concern yourself with extreme detail on these things, all you really need is to find a compressor that will give you the fattest general area of efficiency possible-- no need to get into too much detail with it because they are simply not that accurate the way we are calculating things.

Youre asing good questions though man. Keep at it, I like seeing people who want to get this involved in their build up.

[DRIFTEADOR]

Drift, normally I would say you would be correct, but my reasoning for deciding based on boost is that I have heard horror stories of the KA24DE breaking it's pistons apart due to detonation, so as I understand it, without a tear-down and expensive rebuild it is not a good idea to break the 7psi barrier, and that is pushing it. So, that is why I have picked that.

[Chezedik]

First, I could have been more accurate, I did not mean no timing modification, just no timing advancement like most companies use. Also, I would love recommendations on who to use for chips. Also, when I graphed those they were at a horizontal for a specific boost level, four to be exact and then I speculated that the line could be followed at the same angle from 0-infinite pressure, assuming no other factors. I agree with a point that C-Kwik more than anything, and again maybe he (and I vicariously) am wrong, but he pointed out that the compressor map points out four things RPM, efficiency, flow at a given pressure. So I guess I do not understand how spool up can be mapped on it, without the turbine efficiency map. But another part of me says that for whatever reason, this may be one of those things you just accept, I am just not good at that so I will take an explaination if anyone has one.Also, I first was concerned with figuring out how to boost with a blower, and there are many aspects that are WAY different. Mainly, that a turbos flow is not fixed like that of a blower. As such, a blower builds boost by causing a backup of air in the manifold and flow is fixed. But what confounds me, and please help me with this, since a turbo can internally compress air, for whatever reason, flow is not necessarily dependant on boost. That is to say, when I look at maps from very large turbos, they can move more flow that another turbo at lower boost. But what I would assume is that on a given motor that the only way to up flow was to force it into the engine, i.e. boost. So what this apparently means is that if you dish out for, say, a t04e versus a t3/t4, you will be capable of more horsepower at 10 psi with the t04e. How can it do that? Like I say, you guys know, I don't, so please help.

[fiznat]

I'm going to attempt to answer some of your questions, although I admit I am certanly not an expert on these details.

You are right, spool cannot be accurately predicted on these maps. Not only is a turbine map essential to those calculations, but there are a ton of other variables that cannot be simplifed to just numbers: the design of your charge pipes, the efficiency of your intercooler, the shape of your intake pelenum, possible boost leaks etc etc etc ad infinitium. This is yet another reason why I said that paying too much attention to these numbers and figures is a waste of your time. Calculations are only so accurate in the real world, and should only be consulted in this case to give you a very general idea of what you can expect, thats it.

Your flow question is an interesting one... probably someone else around here is more capable of answering it in full. I am going to consult Corky Bell and see what I can find out haha, so my "answer" will have to wait for now..

[Chezedik]

I agree that is the purpose of the maps, and that is important to me, which is why all the questions, I do not mind a little spool up for a slightly higher top end power, but I would like to figure out what I can expect it terms of larger turbos and spool, if it is just a little difference for a big gain, then it is a no brainer, but that takes me back to flow vs. boost. So, I maybe need to buy Corky Bell book, since everyone else is really into it.

[madbouncy]

The different flow for different PSI on the turbos is mostly efficiency. When you compress air you add heat to it, there's a set amount that physics makes you add and then you have to add more depending on how well the turbo is doing its job. In corky bell you'll notice in the calculations that you have to run more boost for the same HP without an intercooler. It is all dependent on heat, you compress the air and then the heat makes it expand. So if you cool it down it keeps the compressed air dense. When air is cooled down it moves slower. That allows more air molecules into the same volume at a lower pressure. Sorry if my explaination sucks, too many years of low level physics and retarded teachers to explain stuff well.

PV = nRT Pressure * volume = moles * constant * temp

If you raise the temp then either your volume or your pressure have to go up, since the volume is a constant, your pressure has to go up. However, that keeps the moles (amount of air) the same, so you're still making the same amount of power from burning the same amount of air.