questions about turbos

[98-integra]

ok i trying to understand how turbos work can someone please tell if this is right or even close

there are two turbine wheels in beteen the two is a shaft that joins the two wheels when the exhaust comes out of the engine it turns the one on the exhaust side which turn the one on the inlet side pulling in air which goes into the intercooler and cools the air off to make it dense. so the inlet of the intercooler goes from the air intake side of the turbo into the intercooler then out the intercooler and into the thottlebody then what does the blow off valve do release the extra exhaust that you dont need to get to your max boost and what is a down pipe i been reading about them to but i dont really know what there are for or what they do also i was reading more sport compact car mag in feb there a type r that has a turbo and has a "divorced wastegate" that comes out the side of the car if anyone has the mag the pic on page 76-77 is that just so hes not releasing the hot exhaust air in the engine bay? also turbos dont run all the time like a superchager right? so do they work something like the vtec it starts a what ever rpm you want it to and if so is there a why to turn it off so you can save you engine sorry so long but i really want to understand how it works before i spend 4k to get one if this wrong please help me understand and if i have left something out please fill me in thanks

[PWMAN]

You were OK until you started talking about the blow off valve. A BOV goes before the throttle body because when you let off the gas, the TB closes and the turbo is still pumping air. So that excess air needs to go somewhere, hence the BOV.
A wastegate is in the turbo. There are 2 kinds of wastegates, external and internal. But I will just tell you what a wastegate does. A wastegate is a bypass for exhaust to go. There is a mechanism (usually vacuum controlled) that moniters boost and once it reaches a certain point the wastegate opens to bypass some exhaust so you don't overboost.
To the part about a supercharger working all the time and turbo not:
What you might have heard is a turbo doesn't boost all the time, a SC does. Just driving down the road at a certain RPM you will be in vacuum, not boost. But a SC boosts all the time (exept at idle) givin that it runs off the engine by a belt drive-so no matter how much you are hitting the gas pedal at a certain RPM you are going to be boosting so much. But a turbo doesn't give boost until you get on the throttle more because that gives more exhaust to run the turbo. So a turbo boosts according to how much pedal you give, and a SC goes by engine RPM.

[T!mmy]

THANK YOU! I have been wondering what the difference between a supercharger and turbocharger for awhile now. So the supercharger will make your car seem faster all the time while the turbo will make it seem faster at a certain time (like NoS)

[killah_xft]

no... not like nos, not by a longshot. Turbos, add more air to the combustion chamber along with more fuel (if you have upgraded your fuel system as well as turbo controller). this forces more air and fuel into the chamber for a more efficient burn so that your get more HP, and the vaccum of the air flowing through the engine also adds more power, turbos do have a lag period where the turbo is spooling up to full speed, somewhere around 10,000 rpm from the exhaust gases. and during this time an N/A engine would be ahead, but once your turbo is at speed, you will have more power to the floor than the N/A doppleganger will have. Superchargers while they do supply a little power through the entire powerband are limited by how much power they can produce as the blower in a SC is driven by the engine itself it takes power to make power, so whatever power a SC says it will make it's going to loose about 1/4-1/3 of it in the shaft/belts and gearing. each has it's drawbacks, but I would have to say turbos have less problems than superchargers.

[Import_fantasy]

Originally Posted by 98-integra

what is a down pipe i been reading about them to but i dont really know what there are for or what they do also i was reading more sport compact car mag in feb there a type r that has a turbo and has a "divorced wastegate" that comes out the side of the car if anyone has the mag the pic on

yeah i saw that ITR that was in SCC and was also wondering about this "divorced wastegate"

[98-integra]

oh ok thanks so can you turn a turbo off if you wanted to like if i wanted to use it as a daily driver it would just be mine engine and not the turbo but if i was at a stop light and someone pulled up next to me i can just turn it back on ???

[killah_xft]

no, you cannot turn a turbo off, nor why would you want to? you have to remove the turbo completely. the turbo is integrated into your exhaust/intake systems. there's no way to just "unplug" a turbo. it's just there...

[boosted331]

Originally Posted by 98-integra

oh ok thanks so can you turn a turbo off if you wanted to like if i wanted to use it as a daily driver it would just be mine engine and not the turbo but if i was at a stop light and someone pulled up next to me i can just turn it back on ???

Go with your dad (since i'm assuming you're 15, 16-ish) down to a subaru dealer and go take a WRX for a test drive. You can drive the car around all day long and never give it throttle and never spool the turbo. Mash the gas, watch the boost gauge peg, and hear the turbo whistle. Turbos are always hooked up, you can turn the boost down, but not off unless you tie open your wastegate with a zip tie or something, and have your BOV bleed of all boost.

[Irish317]

How reliable is an aftermarket turbo system, if you warm up/ cool off the turbo, and do routine maintenance on your vehicle. I am thinking about putting an aftermarket turbo on my 2003 civic LX. I am concerned as I drive about 35,000 miles a year, and would like a reliable set up!

Thanks,
Irish

[98-integra]

oh ok thanks to the people who help me out and to the jacka$$ that assume i must be "15 or 16-ish" becuase i dont know everthing about turbos sorry i'm not like you and wasn't born knowing everything there is to know please find it in your heart to forgive me please i beg of you please

[killah_xft]

well if you do regular maintenance on the engine, and makes sure the turbo has oil going to the center shaft bearings at a constant rate then it should be fine. just be sure to replace engine oil, and turbo bearings when necessary, make sure turbo timers are all set and your ECU/piggybacks are able to handle the fuel needs (may need larger injectors/fuel rail/high flow fuel pump) that your turbo requires. and don't forget to strengthen your bottom end (low compression pistons/rods) if you are planning to run any higher boost levels than 6psi. and use an intercooler above 7-8psi. depending on the engine wall thickness/strength, and piston compression and so forth you can boost a pump gas engine up to 14psi or so and still be running well. many people when they are just driving the street say they leave it at 6-8 psi with no problems. you can always adjust your boost at the track. but be carefull how far you boost, you can walk (deform) your sleeves, and destroy the engine.

[Polygon]

Hmm, time for a long post. Most everyone in here has said what need to be said but I'm bored and I'll sum it up in one post.

A turbo works by passing exhaust gasses past a turbine wheel. This turns the compressor wheel connected to it by a shaft. The compressor wheel then sucks in air and compresses it into the cylinders. The faster the exhaust passes the turbine the faster the compressor will spin and more air will be compressed into the cylinders. That amount of air has a cutoff controlled by the wastegate. This keeps you from over boosting and helps prevent boost creep and spikes. Turbos also do not like back pressure so a 3" exhaust or bigger all the way from the turbo back is ideal. Removing the cat and the muffler will improve response considerably since there is very little backpressure pushing back slowing the exhaust down. Also backpressure occurs when you let off the throttle this can cause compressor wheels to fail, and cause all sorts of problems. Ball bearing turbos are less prone to this. Still that is why we have Blow Off Valves and Diverter Valves. Blow Off Valves vent the excess pressure into the atmosphere while the Diverter Valve diverts the air back though the intake.

You can't turn a turbo off. A turbo has what is called lag since it takes time to build exhaust pressure to turn the turbine. This is determined by the side of the compressor housing and the compressor wheel. The bigger they are the longer it will take for the boost pressure to rise. Roots type superchargers are different, they run off a belt and the boost is always there when you are pushing the gas. There is also a centrifugal type superchager that works like a turbo. I prefer the turbo since it has more pros than cons and the spuercharger has more cons than pros.

As for how to maintain a turbo car. The best steps are these:

1. Always let the car warm up before going hard on it. This applies to any car. It needs time to get to normal operating temp before you can do any WOT runs. This is a quick killer for any engine.

2. Always let the turbo cool down before shutting off the car. Let it cool for about 30 seconds. If you have been driving it hard drive around calmly for about five minuets then park it and let it cool for about 30 seconds before you shut it off. Not doing this will cause your turbo to die in 75,000 miles or less.

3. Use only 91 or higher octane. If you don't it will cause detonation and you will blow holes through your pistons, forged or cast. Some newer cars have systems to retard the timing or run very rich to prevent this but it destroys your performance and gas mileage. You are better off paying for the 91 octane or higher. Also high boost will require 110 octane or more.

4. Use synthetic. You don't have to but turbos love synthetic. It lubricates much better.

If I think of anymore I will post them.

[Irish317]

I don't mean to steal your post 98 Integra.
Hopefully someone can put me at ease. I want to Turbo my 2003 Civic LX. I am worried about reliability issues. I will try to explain myself: I also own a 2001 Dodge Cummins Diesel, It has a turbo. That motor was built and designed with a turbo in mind. That truck can run with proper maintenance for around 350 to 400,000 miles. My stock Civic with regular maintenace should run 200,000 miles!!! Now if I put a turbo on it and say run boost around 5 psi, can I still excpect the same long life Hondas are known for, or will the turbo shorten its life span?

Thanks to all

Irish

[PWMAN]

Originally Posted by Irish317

I don't mean to steal your post 98 Integra.
Hopefully someone can put me at ease. I want to Turbo my 2003 Civic LX. I am worried about reliability issues. I will try to explain myself: I also own a 2001 Dodge Cummins Diesel, It has a turbo. That motor was built and designed with a turbo in mind. That truck can run with proper maintenance for around 350 to 400,000 miles. My stock Civic with regular maintenace should run 200,000 miles!!! Now if I put a turbo on it and say run boost around 5 psi, can I still excpect the same long life Hondas are known for, or will the turbo shorten its life span?

Thanks to all

Irish

With only 5 PSI you should be fine. It's not a big change to the engine. It also depends on how you drive it too. If you beat the crap out of it of course it's not going to last very long no matter what you do.
BTW, my brother has an 02' ram cummins diesel. He has a 4'' turbo back exhaust and some chip that gives it 320 HP and 690 ft/lbs of torque. His is also a 6 speed. It's really fast for a diesel.