Ok Im looking for answers that I cant find. Basically I want you guys to describe turbos to me... compressor A/R's, exhaust A/R's, what are they? what does everything mean and how do they coincide with each other?

for my purposes my theory is to run about ~10psi max and to build boost relatively low. Im just trying to get a good understanding of turbos.

Also a supercharger basically compresses air straight to the cylinders (compressing) where turbo is basically sucking the exhaust out quickly right? (vacuuming).

Im a roast, baste me. Excuse my ignorance

 

your exhaust pushes air through the turbo making it spool up then the turbo pushes air into your intake compressing air into your cylinders.

A/R is the rated volumetric efficiency of a turbos 2 sections, so to speak. Imagine if you have a garden hose spraying water out at a pinwheel
with the hose open ended, the pinwheel spins okay. Put a nozzle on it an the pinwheel will spin like mad.

There are issues with the nozzle on the end, you lose volume but gain pressure. With the nozzle off you gain volume, but lose pressure and you can't turn the pinwheel as much.

Simply put, on small displacement engines a smaller A/R is better, on large displacement engine a larger A/R is better due to exhaust volume.

A larger A/R will spool later and provide a higher power band, if your engine is capable of reaching the RPMS it should be used in.

 

ok, great example, thank you. Now lets put this even more in perspective... um... say for a 5.3 to build pressure relatively early I should look for something like .68 A/R? also should the exhaust and intake A/Rs be similar or should the intake be smaller than the exhaust or visa verse? Im trying to understand this so if I sound stupid please let me know. Also does the inlet and outlet affect the A/R, are they relative or is it really non essential?

 

I have a .60ar compressor adn a .96 turbine housing and mine raches full boost at around 3200-3500 with a 60-1 turbo mine is currently an sts so its gonna spool a little slower than a front mount but a .68 turbine housing will spool much quicker I will probably lose alittle top end because it will restrict my exhaust. But I wouldn't mind that because I don't like to spin my engine to the moon.

 

Sorry, as far as a/rs one the compressor and turbine the only one that REALLY affects you is the turbine housing. The compressor housing is generally larger for low boost applications and smaller for high boost applications.

 

http://www.turbobygarrett.com/turbob...o_tech101.html

http://www.forcedinductions.com/help.htm

Also look for Corky Bell's book on turbocharger. You'll learn a ton.

When it's all said and done, get a reputable turbo kit builder and follow his advice. There are so many variables and everytime you change a housing or try another turbo, the money you saved doing it yourself just got burned. I went with a Synergy Motorsports kit, bolted it on 2 years ago and haven't looked back. You get what you pay for.

Rick

 

very good read btw

 

got ya, so basically all I need to worry about is turbine housing in .XX measurement and A/R, small for high boost and large for low boost (~10psi and under)?

Thanks man, I really appreciate it

 

I understand that after my engine/tranny swap because the first motor I found was hosed and the trans I found had a bad clutch.

In all honesty though I am not trying to set records or anything which is why the only thing I really am worried about is the turbo. Hell I plan on using exhaust pipe for the intake and intercooler sections, its basically the same thing that comes in the kit anyway. As long as I get my turbo right (which is where the money is gonna get spent) everything else can be on the cheaper side IMO. I could be wrong but theres a few guys running garage kits that are doing just fine.

Thanks for the information and advice everyone, I really appreciate it