Garrett .42/48 for 4.0

4.0 Turbonetics t62 discussion

what do you guys think? too small? just right?

looking for 5-6 psi out of it. should spool up super fast thats for sure, esp with my 10:1 compression ratio. i have a chance to get this turbo for $45. yay? or nay?
No longer going to run the tiny turbo, so discussion will change to this t62 .63/.48 turbo

 

[Bruces expo]

i would buy it if it doesnt have shaft play

 

[Ronin8002]

wow for that price I'd just take a chance and see how well it works

 

[fishy2k8]

Yup it's been recently rebuilt and I bought it. Should spool super quick. Gunna be fun

 

[rocket 5979]

what do you guys think? too small? just right?

looking for 5-6 psi out of it. should spool up super fast thats for sure, esp with my 10:1 compression ratio. i have a chance to get this turbo for $45. yay? or nay?

Anymore information on this turbo you just got? .42/48 doesn't really tell much. What model of Garrett turbo is this? Do you know what vehicle it came off of? Does it have a T25, T3, or T4 flanged turbine housing? Do you know what compressor wheel it has, Etc....? I can tell you what kind of characteristics it will have if I know what turbo it is.

 

[fishy2k8]

It's a garrett a/r t3 flange, not too sure on the compressor wheel, I'll find out.

 

[Jakee]

Yap, I'm thinking you can find out if it's stage 1..2..3...etc...that'll tell you a little more.

Even so, it's small..You'll be maxing out at a lower RPM than the engine can go, i'm pretty sure.

 

[fishy2k8]

not really sure what you mean by maxing out... maxing out what? once it hits 5psi the wastegate will open, what will i be maxing out? im not claiming to know much about turbo sizes and not really sure how to figure out if it's stage 1, 2, or 3

 

[rocket 5979]

Yap, I'm thinking you can find out if it's stage 1..2..3...etc...that'll tell you a little more.

Even so, it's small..You'll be maxing out at a lower RPM than the engine can go, i'm pretty sure.

Stages primarily relate to turbine wheels which is nice to know, but I want to know what compressor wheel he has. Is it a T3 48 trim, a T3 57 trim, a T04E 60 trim or so on. What A/R is the turbine housing and what a/r is the compressor housing? Hey Fishy if you can tell me what vehicle it came off of then that will help out. As of right now there is nowhere near enough information for anyone to have any idea what sort of turbo you have let alone be able to tell you if it is too small for your combo. All I know is that you have a Garrett turbo with a T3 flanged turbine housing that may have a .42 a/r on either the compressor or the turbine, may have a 48 trim wheel or a .48 a/r turbine housing or compressor housing. What does the CHRA (turbo center section) have for a model number on its little metal tag?

 

[fishy2k8]

okay sorry. the turbine is a .42 a/r and the compressor is a .48 a/r. ill try and get the tag numbers from the guy i got it from since he's shipping it.

 

[rocket 5979]

Seen your post in the other thread on RPS. Garrett T3 50 Trim with .42 compressor housing a/r and .48 turbine housing a/r.

What RPM do you plan to rev your engine to, how ported are those heads of yours and what exact amount of boost do you plan to initially run on this turbo. What amount of boost do you plan to possibly run in the future on this turbo? I know you said 5-6 psi but is the the only boost level you ever plan to run with this turbo? I need this information to determine the flow needs of your engine to plot the turbo compressor map for you.

 

[fishy2k8]

plan on revving to around 5300-5500, the heads are stage 3. until the motor gets a stout bottom end this turbo will only be seeing the 5-6 psi. once i have a built shortblock, ill run more boost, but will probably upgrade the turbo as well. so yeah, this turbo will see 5-6 psi, that's all

 

[rocket 5979]

plan on revving to around 5300-5500, the heads are stage 3. until the motor gets a stout bottom end this turbo will only be seeing the 5-6 psi. once i have a built shortblock, ill run more boost, but will probably upgrade the turbo as well. so yeah, this turbo will see 5-6 psi, that's all

Ok, so I spec your total airflow requirements using 4.0 displacement engine @ 85% VE (aka volumetric efficiency), spinning to a max of 5,500RPM's with a pressure ratio of 1.40 (aka 6 psi boost). You total airflow requirements with all that info plugged in is 32.4 lb/min. Here is a quick plot of your map. As you can see the engine requires quite a bit more airflow at that boost level than what the turbo can supply. By the time the turbo is spooled the compressor is already getting less efficient, in this case right at about 70%. I like to size my turbos where my flow falls in the right side of the compressor map as it makes for good boost response in the vehicle but this is a little further right than optimal due to the falling compressor efficiency. But that is no huge deal and you should be ok for what you want.

I posted a plotted map of my Twin Turbocharged Pontiac G8 GT back when it was on the stock 6.0 engine for comparison purposes. As you can see, my plots fall on the right side too, just not as far until I go higher with boost, and my system has essentially zero lag and outstanding boost response. This is the approach I use when specing for a street driven vehicle.

 

[fishy2k8]

for some reason your posts dont fully show up all the way until i refresh.

so you think for what im after this little turbo will be okay? should hold 6 psi through the whole rpm range. i like the idea of the quick spool time

i appreciate your knowledge and help so far

 

[rocket 5979]

for some reason your posts dont fully show up all the way until i refresh.

so you think for what im after this little turbo will be okay? should hold 6 psi through the whole rpm range?

i appreciate your knowledge and help so far

That is not the forums fault it is mine. I have developed a bad habit of posting and then going through adding and editing the hell out of it until I am satisfied that I did not post an inaccuracy or state something in a way that was difficult to understand. Probably a little OCD.

 

[rocket 5979]

so you think for what im after this little turbo will be okay? should hold 6 psi through the whole rpm range?

It may drop some boost on the big end but then again who really cares for a $50 turbo in a street driven truck.

 

[fishy2k8]

^haha it's cool man, i appreciate it a lot. i kept refreshing and was like "woah it's growing" lol

and exactly, it's cheap and it's a daily street driven toy, not a race machine! haha

 

[Jakee]

Sorry about that, I didn't explain myself cuss I knew you were covered with Rocket5979. He is the one that helped me out when I built my set-up so you're in good hands.

What I meant by maxing out, is just what was posted in graph format; that the turbo will start to get out of its efficiency range and heat the air at upper RPM’s. This is because of the air requirement needed for the engine at that RPM. I didn’t map anything, I just knew this from past studies I did playing around with all sorts of turbo maps. (for learning purposes) And once you said it was a T3, I knew that the .43/.48 was the compressor/turbine wheels displayed as a percentage of the T3. That is when I made the post. The stage 1, 2, and 3 actually change the flow characteristics of the turbo. Then, the fine details, you have the inducer/exducer of the turbine and compressor wheels. But this was my thinking and based on the map Rocket posted up, it doesn’t look like this turbo is way out of whack for your motor. I give it a thumbs up.

 

[Jakee]

Whewww...wait a minute. Rocket, at 5500 rpms, it's off the map?

 

[fishy2k8]

sweet guys sounds like my $50 turbo was a pretty good deal then! haha im excited to start putting this all together.

was wondering, im wanting to put together my ic piping from light gauge mild steel tubing so that i can weld it together instead of using a ton of boots and clamps. anyone have a good source to get bends and such for that? and what size piping you guys think i should go with? ill need to ramp it to 3" for about 12" or so for the maf (running blowthrough 05+ mustang slot maf) but other than than, 2.5"? 2.25"?