I was wondering what turbo comes stock on the 1980 Firebird Formula turbo.

 

T3, 60 trim cold side, .82a/r hot side

 

I am thinking about running one of these on a 302, how much boost is one of the capable of?

 

On that engine, not much. Two of them would work great though.

 

I was figuring it came off a 301 so it sould run a 302 fine. I am only looking to run about 5psi. I just want to know if it can do this and how much boost is this turbo capable of on an engine like mine. Also just for curiousity how much boost is the stock turbo pushing on a 1980 firebird turbo?

 

They made 210hp at 9 psi.
You want to worry about airflow capacity before worrying about boost level. They can't flow all that much air.
Read through this (then turbo tech 103, or start with 101 and read all three if you need to)...
http://www.turbobygarrett.com/turbob...o_tech102.html

FYI, my Talon stock made 210hp at 11 psi, with an itty bitty T25 on a 2.0 liter.

 

My car is making 200hp n/a but that is besides the point. I read through the info, very good by the way, but it did not answer all of my questions. What is the difference between airflow capacity and boost, its seems like they should be the same thing to me. The more air you flow the more boost you will have. Is there info about the differnces between turbo numbers, for example what is the differnces between T3, T4, T25, T70, etc. Thanks

 

Logicly speaking assuming a certain air flow for a certain boost level is like assuming that you'll make the same HP just because the engine has the same displacement. The 301 you're getting the turbo off of makes ~150hp in N/A form, compared to your 200 hp N/A engine with only one more cubic inch.

While there are plenty of guides out there on how to turbocharge, I'll give a short explanation.


This is a turbocharger compressor map. If you look there are concentric areas on this map, these denote a certain efficiency of this turbocharger. To the left side is the pressure ratio, this is how much "boost" you're running. Most of these are in atmospheres, so if it's 2.0 that means 2.0X14.7 or 29.4 PSI absolute pressure, or 29.4-14.7=14.7 PSI of pressure above atmosphereic pressure. The bottom is in cubic meters per second, most maps I've seen are in CFM or lbs/minute of air. You can interchange between these units, you just have to get the conversion factor from the internet. If I was you I'd get some books and start reading, you've got a long way to go.

 

I dont currently have access to a library, do you have any recommendayions for online reading? Well my friend I going to junk his 301 and he said I could have the turbo and piping for $20, but if this will not work on my car I will go and spend the money to get something else. For the time being I want to keep the boost low because I am running stock internals. I think I am starting to understand. Tell me if I am wrong here, the pressure ratio is the amount of boost the trubo is "capable" of making, while the flow is how much air it can push and and the map shows how the combo of the two match up.

 

that 301 stock flowed about as much as the 3.4l from a 93-95 camaro, hence the 60 trim t3. your engine(i sure hope) will be flowing a lot more than that, so you will need a bigger turbo.

flow is how much air the turbo can pump out. pressure ratio is the resistance the turbo compressor has to work against to push out more air. not only do different sized turbos push out different amounts of air, but they are also tuned to push out that much air against a certain resistance. so a huge turbo can put out the same amount of air as a small one, but if you put it on a lower breathing engine it would underperform becaue the pressure ratio would be off the chart. a lot of people dont realize how complicated turbo sizing can be.

that turbo on the stock 301 pushes ~330 cfm of air at 9 psi(note: stock 3.4's flow ~250 cfm at 0 psi, and ~400+ cfm at 9 psi, with almost 100 less cubes!). if you opened up the heads/intake/exhaust of that 301, the turbo flowing the same amout of air would be making less boost. Boost is just the leftover air that has nowhere to go. a better flowing(higher volumetric efficiency) naturally aspirated engine will make more power at lower boost than a worse flowing one.

never pick a turbo based on what different engines are running, especially factory engines. turbo sizing is crucial and as i said before, somewhat complicated to the untrained/unaware. i suggest picking up a book. Maximum Boost by Corky Bell is good, as is Forced Induction Performance Tuning by A. Graham Bell. There is a wealth of information on the internet, but as is typical with the internet a lot of it is misinformed and/or incomplete.

 

So baically more efficient engine, bigger turbo. But how do you figure out what size turbo you need and how much cfm your engine can flow? Is there anywhere that lists what the different turbo differences are between models?

 

Okay first, it wasn't beside the point, I was making a point about how small that turbo is by comparing it to others.

That link I gave you correctly and throroughly explains compressor maps if you read all three of the sections, If you don't understand what it says, then ask more questions about them. To grasp that though, first read my explaination on boost vs. airflow:

Think of it this way. Go get a fat straw (drink straw) and a skinny straw (coffee stirrer). Put the fat straw in your mouth and blow. Feel the air come out the other end. Now put the skinny straw in your mouth and blow with the same amount of force and feel the air come out the other end.
Notice how the fat straw flows a lot more air than the skinny straw at the same lung pressure? Bingo.

You're fine if you only want to make 200hp at 9 psi through that little straw (301 with tiny intake/exhaust passages), but if you want to make 400hp at 9 psi through that big straw (302 with much bigger intake/exhaust passages) because it will flow more air at the same pressure, you need bigger lungs (bigger turbo, or two) because yours aren't quite up to the task (not insulting, just using examples, heh).

Get it?

Now if you grasp that, go read the articles in full, and what others here have explained.
The charts you want for turbo sizes are the compressor maps. The place I use for most Garrett compressor maps is here...
http://64.225.76.178/catalog/compmaps/fig1.html

Now, that's all only about the compressor side. You also need to match up the turbine side to your engine, and the compressor side. Too small of a turbine housing/wheel will spool fast but choke off top end power and possily overspin the turbo, too large of a turbine housing/wheel will take a long time to build boost which will take away low end power you could have. The trick is to get a combination with the best of both worlds. Get the compressor side stuff first, then go on to worry about which turbine side will match up and what not. I gotta go for now.

Hope this helps.