n00b question - turbo related

[DjLiquid]

Before I get flamed, I just wanna say IM NEW :P.

Ive owned 2 CA18DE's but I got a CA18DET from Rafic in March. I rebuild most of it and was wondering if anyone can hook me up with a website that will explain the more into depth topics of how a turbo works. I understand exhaust forces the turbine and then in turn, the other side of the turbo compresses the air and forces it into the intake but with all the other talk about internal wastegates (i know what an external is), bar's (ex: "my turbo can handle 1.7 bar") and 255 cams, and whatnot, I was wondering if anyone can point me in the right direction so I won't be asking hundreds of questions and taking up your guys` time. Thanks =D
Modified by DjLiquid at 11:53 AM 4/20/2005

[teddy]

heres a nice write up on turbo's and components. hope it helps somehttp://www.turbo-kits.com/how_turbos_work2.html

[c-rad]

http://auto.howstuffworks.com/turbo.htm

[DjLiquid]

http://auto.howstuffworks.com/turbo.htm

Yeah. I read that one a while back and it was ok but they didnt go really in depth to the point that I needed it to.

[outcastcat]

check to see if SCC has written a SUCK BANG SQUISH BLOW on it yet. Theyve covered both types of supers, so maybe they got turbos done too. should be on their sitw http://www.sportcompactcarweb.com

[nocwage]

with all the other talk about internal wastegates (i know what an external is), bar's (ex: "my turbo can handle 1.7 bar") and 255 cams,

Wastegates are used to control how much boost a turbo makes. When the wastegate opens exhaust gas can flow around the turbo instead of through the turbine. This is how they control how much boost you make. Without a wastegate the turbo wouldn't stop trying to spool and would very quickly destroy itself.An internal wastegate is jsut that, it's built INTO the turbo, the stock T25/T28 etc all have internal wastegates, it's that little "flap" you see next to the turbine on the exhaust side of the turbo. An external one is built into the manifold and again it allows exhaust gases to bypass the turbo.

"Bar" is just a measurement of pressure.1 Bar = 14.5~ psi. bar is the "metric" measurement for pressure.Also on a boost gauge that has psi you'll see "in. Hg" Hg is the elemental sign for mercury, like temperature mercury could be used to measure vacuum, I don't know the sizes of the tubes etc but if you have 30 in. Hg vacuum then that vacuum would have made X amount of mercury in a barometer's tube expand up to the 30 inch mark.

"255 cams" referes to the duration.If you've seen a cam you'll notice it has lobes that stick out. These open the valves so air/gas can get in and exhaust can get out. THe number represents how many degrees of rotation the valve will be open by the cam.So a "255" cam would have the valve "open" for 255 degrees of rotation. (out of the obvious 360 degrees).THis is all jim dandy, however the other important part of the cam is "lift" which is how far it actually OPENS the valve.Longer duration and higher lift will give you more power up top but you'll lose out down low in the rpms, you also won't idle as smoothly etc and you're fuel economy and emissions will suffer.

I hate to bring up hondas but that's what's neat about vtec. they have two lobes of different lift and duration, when you're "on vtec" the rocker arm follows the aggressive cam and opens the valves further and for longer, increasing upper rpm power. When you're not on vtec it uses the more fuel economy/emissions friendly lobe.

[nocwage]

Also if you don't know you can do neat quick calculations with google. Go to google and put in "7psi in bar"

[float_6969]

Flame away, but it's a pretty neat idea and it works. Well. Take that head design and throw it on a Nissan cast iron block, and I'd be all over it! (I'm not much for aluminum, open deck blocks)

[nocwage]

Flame away, but it's a pretty neat idea and it works. Well. Take that head design and throw it on a Nissan cast iron block, and I'd be all over it! (I'm not much for aluminum, open deck blocks)

Well... the SR20(16)VE(T) has a system that is more like the "new" i-vtec.It's still aluminum block, but it's not opendeck, and it's nissan, and it's been around longer NEO-VVL

Check this site outhttp://www.autozine.org/techni...1.htm

It's pretty neat, goes over the different variable valve timing AND lift of the various manufacturers!It's a good find, check it out if you're a tech geek.

[outcastcat]

yep a SR20VE has been sold stateside in a transverse format. it makes almst 40 more horsepower (175/180 vs. the old SE-rs 140)