BMW Werkz banner

1 - 10 of 10 Posts

·
General Chaos
Joined
·
13,803 Posts
Discussion Starter #1
Ok im no expert but i think alot of us with the e36 non-m's or even m's feel like we have not enough power. So basically im trying to start this thread so that we can cover the basics and requirements, to maybe even the professional DIY of install and testing turbos.
Please add to this as needed for I am still learning.

First off, What is a TurboCharger?

(Howstuffworks.com) - Turbochargers are a type of forced induction system. They compress the air flowing into the engine. The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine.
In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump.

What is Boost?

Turbochargers allow an engine to burn more fuel and air by packing more into the existing cylinders. The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50 percent more air into the engine. Therefore, you would expect to get 50 percent more power. It's not perfectly efficient, so you might get a 30- to 40-percent improvement instead.
One cause of the inefficiency comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. This subtracts a little bit of power from the cylinders that are firing at the same time.

How It works

The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons.

The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin.

On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.

In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts, and it allows the shaft to spin without much friction.

Possible Downsides of Turbo
Too Much Boost
With air being pumped into the cylinders under pressure by the turbocharger, and then being further compressed by the piston (see How Car Engines Work for a demonstration), there is more danger of knock. Knocking happens because as you compress air, the temperature of the air increases. The temperature may increase enough to ignite the fuel before the spark plug fires. Cars with turbochargers often need to run on higher octane fuel to avoid knock. If the boost pressure is really high, the compression ratio of the engine may have to be reduced to avoid knocking.

Turbo Lag
One of the main problems with turbochargers is that they do not provide an immediate power boost when you step on the gas. It takes a second for the turbine to get up to speed before boost is produced. This results in a feeling of lag when you step on the gas, and then the car lunges ahead when the turbo gets moving.

One way to decrease turbo lag is to reduce the inertia of the rotating parts, mainly by reducing their weight. This allows the turbine and compressor to accelerate quickly, and start providing boost earlier.

Small vs. Large Turbocharger
One sure way to reduce the inertia of the turbine and compressor is to make the turbocharger smaller. A small turbocharger will provide boost more quickly and at lower engine speeds, but may not be able to provide much boost at higher engine speeds when a really large volume of air is going into the engine. It is also in danger of spinning too quickly at higher engine speeds, when lots of exhaust is passing through the turbine.

A large turbocharger can provide lots of boost at high engine speeds, but may have bad turbo lag because of how long it takes to accelerate its heavier turbine and compressor.

Intercooler and its importance

When air is compressed, it heats up; and when air heats up, it expands. So some of the pressure increase from a turbocharger is the result of heating the air before it goes into the engine. In order to increase the power of the engine, the goal is to get more air molecules into the cylinder, not necessarily more air pressure.

An intercooler or charge air cooler is an additional component that looks something like a radiator, except air passes through the inside as well as the outside of the intercooler. The intake air passes through sealed passageways inside the cooler, while cooler air from outside is blown across fins by the engine cooling fan.

The intercooler further increases the power of the engine by cooling the pressurized air coming out of the compressor before it goes into the engine. This means that if the turbocharger is operating at a boost of 7 psi, the intercooled system will put in 7 psi of cooler air, which is denser and contains more air molecules than warmer air.



The Good Stuff:
What Components Do I need to Turbo my Car?

A Turbo
Turbo Manifold
Intercooler
Bigger Injectors
Downpipe
Wastegate
Blow Off Vavle
Piping and Hoses
Custom Software

How much will it cost?
Price will always vary depending on what kind of parts you want and what kind of power your looking to gain. I've seen kits go for $3500+

Turbo/Supercharge Vendors for BMW E36
http://www.turbokits.com
http://www.activeautowerke.com
http://www.dinancars.com

like i said before, i dont know everything, any more add-ons or info would be much appreciated...
 

·
Registered
Joined
·
9,482 Posts
And your car has to have V-TEC+stickers. dont forget.

Honestly this is all common knowledge material so far, if we get some more input that soem of us might take time to post (not me) then maybe this thread can be stickied.

Prefferably not cause I dont like you speed. You and your LA smog. you die.
 

·
General Chaos
Joined
·
13,803 Posts
Discussion Starter #4 (Edited)
///M Power said:
And your car has to have V-TEC+stickers. dont forget.

Honestly this is all common knowledge material so far, if we get some more input that soem of us might take time to post (not me) then maybe this thread can be stickied.
i know this, but it seems alot of people, including me, didnt even know all this stuff, at least now if you start posting more advance stuff there is no room for, "so wat does a turbo really do? or do i really need a intercooler?"....
and post something useful eric or ill smack u...damn indians...
and yes jester i just come to umrica and know the www.com internet :p
and again, add useful stuff not ur pansy comments :)
 

·
Registered
Joined
·
3,109 Posts
Well, at least I can see the value of this post with regards to the "h0w mUCH izza TuRb0! Its teh r0x0r!!!1!1! lolomfg" questions. Of course with a knowledgeable audience, it would also be fair to include a supercharging thread so that people can compare.
After all, I (and I'm sure other m3 owners - I can't be the only one) would prefer to supercharge rather than turbo and mess up my power curves.
 

·
Registered
Joined
·
267 Posts
Yeah, I wasn't harassing you with my comment. Whatch your responses to other peoples' posts, lest the become offended.

As for what 4evrwyntr posted, I agree. Looking into twin-screw for mine eventually. Just need to get more boost and way more HP
 
1 - 10 of 10 Posts
Top