Turbo's 101

Rat Rods Rule

Help Support Rat Rods Rule:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


'Vette brake specialist!
May 16, 2007
Visalia, CA
Ok guys, this is a very very bare bones turbo tech 101. It's for the guy that dosn't even know what to google or look up when he's interested in doing a turbo set-up. I also wrote it after drinking four corona's :D. I would wait until it's a bit more fleshed out but i don't know when i'll get to it. I'll add more to this thread as I get time as well as links and a nice list of cars with good turbo components at the junkyard.

Junkyard turbocharging!

So you want to turbo charge your rat rod? Problem is....turbocharging aint cheap. But it can be done on a budget. There are a couple of things to be taken into consideration.

Rule #1:
This is the end all of every turbo build you will ever do! It is a fact! Listen carefully! Boost is air, you can put as much air into your engine as you want based on two things. The first is that you need to maintain the proper air to fuel ratio; this varies from engine to engine but the bottom line is that increased air requires increased fuel. The second guideline is that you can run as much boost (air) as you want; as long as your rotating assembly can handle the increased pressure. Keep these things in mind as you plan your build and your engine will survive.

Rule #2: Please see Rule #1.

So? What does a turbo do?

Basically- A turbo utilizes exhaust gas to drive a compressor that shoves air into your engine. More air equal’s more power!

Ok, what engine should I use?

90% of stock oem engines can handle 6-10 pounds of boost as long as they get enough fuel. After that it is all relative based on the engine and what you can do to make it internally stronger. So just try it and see what happens. (this may not be true for really old style engines though.....as in flatties...i don’t know)

How do I know if my air/fuel ratio is correct?

Oxygen sensors are your friend! A universal oxygen sensor is available through just about any parts house (or any junkyard-but new is better). They thread into a bung that you weld into your exhaust pipe. Hook it up to an air/fuel gauge and a 12v power source. It will tell you what your ratio is and you can tune from there. There are two kinds; narrow and wide band. Narrow is the cheapest as it only states “LEAN” “STOIC” “RICH”. Wideband costs more but it will tell you exactly where your ratio is. Much better for fine tuning.

Carb or fuel injection?

You can go with a carb on this if you want. Google blow through or draw through turbo systems for more info. Generally though, fuel injection is much better for this. It’s not as complicated as you think and is electronic. This lets you program it the way you want versus having to adjust a carb to handle increased boost levels which is not nearly as reliable. You can keep your costs down by googleing MEGASQUIRT. If done right you can have your engine programmed for less then $500. Pretty cheap when compared to the cost of pre assembled computers and wiring harnesses.

Exhaust manifold or turbo headers?

Going with an engine that came turbo charged from the factory makes this easy as you are already set as far as a turbo exhaust manifold goes. However, most of us would rather turbo charge a big block chevy motor.:D ATP Turbo sells a variety of exhaust flanges and ducting that will suit a variety of needs (learn to weld).

Oil cooled or water cooled?

The turbo impellers run at about 100,000 rpms......might be a good idea to keep em cool. Most oem turbo’s came water cooled from the factory, so 99% of junkyard turbo’s will be water cooled. This increases the life of the turbo when compared to a turbo that is only cooled by oil (most aftermarket performance turbos). However, oil only turbos are easier to install as you only have to worry about the oil return and delivery versus figuring out water supply and return as well.

How do I control my boost level?

Use a wastegate. Without one you will see boost levels of 30 pounds to infinite. However, I can only guarantee one 1/4 mile pass before you send your crank through the oil pan and your turbo through the hood. If you want more then one pass you will need a wastegate. They control boost by venting excess pressure to the atmosphere. They are available in internal and external variations. Internal wastegates are part of the turbo and are limited in boost pressure. If you want to go with more then 20 pounds consider an external wastegate. These are used with a turbo that has no wastegate built in. They are welded into the exhaust manifold pre-turbo. Because they are a seperate component they are available in larger sizes to control higher levels of boost. (almost forgot...use a manual or electronic boost controller to set the boost level a wastegate bleeds off; internal ones have a pre-set pressure but can be controlled with a boost controller as well).

What turbo should I use?

Depends on how much you want to spend. Most junkyard turbos are good for 6-10 pounds of boost. Any more and you should look at aftermarket turbos. The bigger the turbo the more the boost you can get, however, it will take longer to deliver that boost as it has a bigger compressor to spin. Google turbo lag for a detailed explanation.


The turbo is spinning at 100,000 rpm’s and is being fed by hot exhaust gasses. Naturally it will pump out hot air. This is no biggie if you only want about 5 pounds of boost. Use an intercooler to cool the air down for higher levels of boost. It’s basically a radiator for the boost. Mount it in the air stream based on your car’s design and route the air from the turbo to the intercooler, intercooler to the intake. Intercoolers are available on ebay, the junkyard, and any number of performance shops.

Like I said, a quickie overview. Feel free to shoot holes in anything you see incorrect. I'm no engineer and I've never built a system from scratch. I've only played with cars that came boosted from the factory. I'll keep adding info to this thread as i get time. thanks guys!
having a turbo car can be the coolest thing in the world, but seriously it is going to cost you some dough, and it is alot of maintance, and carefull use.
once you go boost you will be addicted, and when it breaks you will want to cry, it's like going from a corvette to a chevette, over a little vacuum leak, and if you don't have it getting cooled enuff or enuff oil it will go out if you don't have it rich enuff your engine will blow, ninety percent of junkyard turbos are good for parts or rebuild only, most are garbage and have cracks in them or will by the time you get em apart, no-name ebay turbos are turds too, theres a ton of good stuff out there though, you just have to really do your homework and be patient in the trial and error part of your project, and rebuilding them yourself is possible and inexpensive, really do the research because there are places around here that rebuild for 700 bucks, and then 2 miles away there's another place that rebuilds em for 300 with same parts same warranty, only it takes the 700 dollar place same day, while cheaper place takes like a week, but don't bother with hotrod shops or tunercar places, try the deisel truck places that specialize in injection and stuff like that they will have tons of parts, most are pretty universal, and they will have crazy intercoolers and stuff that you won't find in most car junkyards.
You make a very viable point.

A HUGE HONKIN torbo from a peterbuilt would fit the theme of my truck well.

wheels are turnin, head is smokin.......
darn tootin those big turbos rock. you're totally right though about junkyard turbos being junk most of the time. if you know what to look for though it can work out. the suckie thing is when you spend an hour in the hot sun pulling a turbo just to get it off and see that there are cracks in the housing and the shaft is loose. :( oh well, that's how it goes. $50 turbo's versus $1000 turbos. :p
im not sayin im against turbos in anyway, i love em, best of luck to all,
im just saying having a turbo vehicle running good is like having a really hot girlfriend, and having a broke turbo vehicle is like having a hot girlfriend thats allergic to your penis

Latest posts