I am new to this turbo stuff, but I have been reading through the articles at a GN website to try to learn more.
I have a 350 ci. 4 bolt, steel crank, hyperuetic pistons, 76 cc poorly smallish port heads(pretty much junk but fresh, a 214/214 duration .454 lift cam. The compression is about 9.2:1. I could care less about blowing this engine up and I want to learn about turbos by actually putting one on it. I was going to weld-up/modify some regular mild steel headers. I only plan to get maybe 4 months of use out of them.
I was thinking of using just a couple of used T3 turbos. I have looked quite a bit, but I can't figure out what "A/R" stands for. What is it? Also, what are the odds that the headers crack in 4 months of use. It is not a daily driver, just a project learning car. How much boost do you think the engine could handle? I am going to run it on with a 1986 TPI setup and a a '749 (turbo) ECM. I know how to reprogram PROM so timing and fuel issues are not a problem (well, if I don't blow it up by accident.
Anything you have say is appreciate...I am expecting a few flames on this one anyway.

Thanks,
J

 

Why are you expecting flames? Anyway A/R simply stands for Area/Radius of the housing. If I understand everything, varying the A/R will change spool up. A larger A/R will have a slower spool up than a smaller, but the larger will not choke as much on the top end.
The headers most likely won't crack. People have done setups like this that have lasted for four YEARS, so they should last for a couple of months.
Boost depends on lots of things. Intercooling, heat, fuel, etc. It's something you're just going to have to experiment with.

 

Thanks for the resonse. I was expecting some flames due to the junk turbos, mild steel headers, baby cam, dinky heads. I'm just looking to learn a bit, not looking for '12's or '11's.
That makes sense with the A/R definition. I friend offered me a single turbo of an 8-71 detroit engine(diesel). I don't think this engine would have a chance trying to spin it. I can't find a map for it either. I figured the small twins would be better. It is a little more work but I don't care about that cause it definitely isn't going to be pretty. No, I am not degrading a 3rd gen. I am throwing it in a pick-up. Plenty of room in the engine bay.
I understand what you say about the boost and heat and all that stuff. I would say no intercooler here. I can get my hands on either oil cooled units, or oil and water cooled units. I am guessing the water cooled would be better? Right? More work though, maybe I'll just go with the oil cooled ones. I'll have to do some more math there.
I was planning on using wastegates that are controlled by the ECM. Has anyone been using this sort of setup? I could ramble forever. Alright, back to the GN site. Thanks again.
J

 

You're doing this to your pickup? Sweet! For some reason I have an urge to turbo the 305 in my 74 pickup. Oh well. Anyway......
If you're doing a junkyard setup and you use T3's like off a T-bird you dont even need to hook up the water lines. A lot of guys that have done this have just left the water lines off and the turbos have worked fine. Just keep the oil changes frequent and they'll be okay.
Without an intercooler and with around 9.2 compression you should be able to get at least 6psi before detonation, just depends on the gas you can get and a lot of other variables.

 

don't worry about taking the junkyard approach, whatever works.

WRT the T3's, if you can control detonation they are enough to put you into the low 10's in an F-body, so don't laugh at them (BTW, that's what I'm putting on my 350)

If you don't know what the turbo is off the Detroit diesel try to find the displacement and RPM. Typically diesel's spin at about half the RPM that a gas engine does, so you're looking for a turbo that is on an engine about 2x the size of the gas engine that you want to turbocharge. If you’re willing to ‘suffer’ with a turbo that’s a bit small for a 350, but that will feed about 500 hp, look into the turbos used on the ford powerstroke/Navistar engines, they run under $200 on ebay.

 

I just found out that the twin setups I can get are the .42 / .48 T3's. According to the equations on the GN site they would not work on a 350 ci. at 5600 rpm. I wonder what the max boost would be using them? HP?
Anyway, I'll take a look at the diesel unit again. It still had the tags on it, but there was no visible part number. I'll look harder tomorrow. I would really like to go with a twin setup though. I found some maps for a T3 "40" and T3 "45". I was using the T3 "40" map for the A/R .42-I, .48-E turbo calculations. Was that the right thing to do? If at high RPM I ran them at the far left edge (less efficient) part of the curve it would just stop making boost, right?
Thank you for the help. The info. on the diesel makes sense in terms of ci. and rpm.
J

 

I think that you’ve got something confused, the .48AR turbine is fairly common, but there is no 42 compressor that I know of, there is a 40, 45, 50, 60, and super 60. As far as I know the common compressors that can be found with the .48AR turbine are the 50 and 60. The 60 (automatic turbo coups and some other ford 2.3’s as well as I believe some saabs and Volvos) would be fine, if a little small (I know someone running 2 of them on a 440 Chrysler that revs to over 5K). The 50 (Chrysler turbo motors, saabs and volvo’s) wouldn’t be worth while unless you’re building a truck motor that is all low and midrange.

 

BTW, I think that you've got your compressor maps confused. If a turbo is small you'd be running it off the far right edge, if the turbo is too large you'll run across the surge line which could feel like lugging a manual tranny car and could damage the turbo bearings.

Running it off the right edge, well, as long as you're somewhat close all that happens is that you loose adibiotic (sp?) efficientcy, in other words, you create more heat to produce the boost.

 

Yeah, you are right about the left edge and right edges of the maps. I was thinking right, but wrote left instead. I think what happened was that I was thinking about big diesel turbo having the surge problem on my engine.
You are right about me being confused about the A/R figures. Both the intake and exhaust have an A/R figure, right? I think the twin setup I can get is a set of Saab units. So they would probably be the .48 exhaust type. How can I tell if I can use the T3 "45" or T3 "50" maps for them? I am going to head down to the garage and see what info I can get on the detroit diesel turbo. Anyone know how much and how complicated doing a rebuild on one of these is? Just regular hand tools, torches, welder, stuff?
Thanks for the help.
J

 

as far as I know, the 'trim' (for a T3) is the compressor AR, so a 60 trim is a .60... Even if it really isn't it doesn't make a difference since you know that you can get a map of what the compressor will do.

Saab T3's could be 40's, 45's and 50's depending on the year and model (I don't think that any of them ran a 60, and I don't know of anything that ran a super 60 stock)

The compressor trim is usually cast into the housing.

If you're lucky, the DD turbo is a T-04, then you have some chance of finding a map, otherwise you're stuck using the 'rule of thumb' about displacement and rpm that I stated before (and usually diesel hp is about half of what it will make on a gas engine), and inducer and wheel sizes to guess if it will work.

Rebuilding them is usually fairly easy if you can get the bolts out. I believe that the only really special tool that you might need is snap ring pliers for some (not sure that qualifies as a special tool), and there are all sorts of picky ways to tighten the compressor nut, but generally if you do it carefully with an inch/lb torque wrench you'll be fine.

 

Thanks. I looked at the diesel turbo again. It is marked .75 Garrett. I'm try looking for a map. It sounds pretty big.....looks it too.
J

 

Would a T76 have an A/R of .76? If it does, then this turbo looks like it would work. I have to do the equations out for low rpm to see if it makes the surge limit, right?
Thanks,
J

 

Did you get any part #'s off of it or measure the inducer?

Sounds like a T-04, but I'm not sure what it is. Very few of the part #'s have been translated to the trims as turbonetics sells them, so it's hard to figure out what you've got unless you've got one of those part #'s or if you measure the inducer and wheel sizes and compare them to turbonetics published sizes.

Be aware though, that you won't see something like a T76 as a factory part on anything, this is just a designation that turbonetics assigned to them.

 

BTW, knowing that it's a .75 AR turbine barely helps you at all, all that tells you is how fast the turbo will spin up relative to another similar one with a different AR.

The compressor side totally decides how much air the thing will pump.

 

I looked for a part number but the only thing on it is a rebuild tag with some numbers. I'll post them tomorrow. I tried searching the web for them before but I didn't come up with anything.
The .75 A/R was on the intake pump housing. I couldn't find anything on the exhaust except for the rebuild tag. I will measure the intake (inducer?) hole tomorrow. Actually, I'll measure all of the inlet and outlet holes tomorrow. I got sidetracked tonight messing with this LT1 intake thing.
I guess if I measure everything I can kind of match it up with something that is published.
Thanks for helping me with this.
J

 

yea, your best bet at that point would be to spend some time on turbonetics, and maybe gntype or similar sites and try to match up any dimentions that you can get for the compressor.

Unfortunatly I doubt that I'll be any help there...

good luck

 

Years later I come across this thread while doing a search. I did find out what that unit was a while ago. It is a Garrett TV series T6 unit.

 

Heh, talk about drudging up old posts…

TV’s aren’t T6’s, but judging from what I know now sounds like one of the TV series turbos… not a bad turbo but you need a serious engine to spool most of them.

 

What is the TV series classified as in terms of the T# label? I thought all the TV7x and TV8x series had turbines called T6. I don't know if Garrett came up with the T# label or it is a Turbonetics confusion thing. I know the TV75 and TV81 have turbine inlets that are huge compared to the HX55 turbine inlets. Well, from what I have seen.

 

That’s a loaded question… The TV’s are the replacements for the bigger T0x turbos and the GT’s are the replacements for the smaller ones. They don’t really have anything to do with each other.

The reason that that becomes a loaded question is that the larger T04’s got designated things like T60, T70, T72, T88… and have nothing to do with the original garret designation. They’re basically a T04 frame with some other, larger compressor on it. As best as I can tell there isn’t even really any standardization there. I know one of the T88’s uses a Hitachi cold side, and the master power Txx turbos are completely different then the precision ones… so to give you a technically correct answer, someone might be using a TV compressor on a T04 style Txx, but I don’t know what that is. To make this even more confusing, there are now Txx turbos using GT series cold sides, and even worse, in some cases you can get the same one on a T04 or T06 frame…

 

If its off an 8v71 its prolly 1985ish or older I dont remember when they quit the 71 series, I think they made the 92 series till 87 or 88, if that helps. That thing should move some air off of one of those, 568cid, two stroke, around 350 - 450hp @2100-2300rpm depending on year. I have an old non electronic 8v71 but its a non turbo 318hp @2100rpm.

We rebuild alot of 8v92's at werk, mechanical and electronic ones, if I get a chance I'll see what I can come up with on those

 

It is a TV7512 off of a detroit.

All of the T-series maps floating on the web never state the trim size for the map. I think majestic is the only site that gives the wheel specs also.