Starting a FAQ for this section, will try to keep it updated, PM me if you want anything added or sugestions.
Some good reading for the basics about turbochargers and understanding compressor maps
thanks to Jose (JZ 97 SS 1500) for this
http://www.forcedinductions.com/help.htm What other things do i need when i boost my beast You need the proper balance of fuel, air and ignition
the more air you put into your engine the more fuel you will need
so bigger injectors and bigger pump are a must., after ALOT of power increase you will have to upgrade your fuel lines and fuel rails.
Tuning, you need to have it tunned properly
the only HP limit the lsx engine see is tunning, no one tha i know of have split their block because they made to much power, but i have seen alot of times where they put a hole through their block because of poor tunning.
Drivetrain: you need to have stronger componets to handle all that extra power your now running. You need a stronger clutch, built tranny, stonger driveshaft and rear end.
Suspension: you have to put the power to the ground if you want to make use of it, so get your suspension worked out. Get a strong torque arm too, so it doesnt end up braking.
How much boost can i run
0-infinate Psi
basically you are limited to octane and timing, the more boost you use the more easily the mixture can pre-ignite (which causes knock), so you have to use a fuel that ignites on a higher temperature (aka higher octane fuel) or pull enough timing.
to give a ruff estimate most people use about 7psi on a stock compression ratio engine (10.1-10.5:1)
if you lower the compression ratio in your engine by larger combustion chamber heads, thicker gaskets or dished pistions, this will also allow you to run more boost on the given octane.
What size turbo should i use http://www.forcedinductions.com/help.htm has alot of good information on selecting a turbo that will suite your needs.
Basically you need to start by knowing your power goals. Select a turbo that will support that power level.
next where in the RPM range it makes its power is also important. This can tuned by selecting the A/R of the exhaust housing. the smaller the AR the faster the turbo will spool and make more power, lower in the RPM range, but will choke off power in the upper RPM range. A larger AR will spool later in the RPM range, but will make more power in the Upper RPM range.
why isnt anyone running 30psi or more on an LSx engine like the imports do
psi or boost is resistance to flow
psi is irrelevlant, how much air goes through your engine is important. ALot of people give an example of two straws one really thin, one large. If you blow into the small staw it is harder as the velocity of the air increases, but not a whole lot of air is moving. Switch to the larger staw, it is easier velocity is low but your pushing alot of air through it.
these 346 cubed or larger engines flow very well. so 15psi can make around 700rwhp.
UPDATE: casper from W2W has ran a 6.866@205 with around 30-40lbs of boost. First production LS-style block in the 6's! so hows that for comparing it to import boost level.
how much power will i make if im running Xpsi or increase it xpsi?
there are alot of varibles and some other thing in contribution, but if you start out with what your engine makes NA
(0psi) you double the power at 1 atmosphere (14.7psi or 1 bar) so we can come up with a rough formula of
new power = [ ( NA power / 14.7 ) * amount of boost ] + NA power
Can i run a turbo on my high CR engine and low lsa cam
Not really, well yes but it wont do as well. WIth a higher CR then stock your going to have problems not running high enough octane, you will be fighting knock so you wont be able to use enough boost to make it worth your while.
The low lsa cam also isnt best for your turbo, it will bleed off boost and not give enough gas flow velocity till the upper part of the RPM range.
what cam should i use with my turbo set up?
There is alot of debate here but first off the stock cam does pretty well. a higher lsa seems to be more desirable 114-117. this will bring the exhasut gas velocity up faster and spool the turbo more in the rpm range and not tend to bleed off boost. It needs to be matched to your setup also when you want the power to come on, and how high you plan on spinning your motor.
for the duration it needs to be matched to your engine size, intake and exhaust manafolds. The larger the engine the higher overall the duration should be. It was explained once to me that you want the intake duration larger then the exhaust that way you have a higher exhaust velocity which helps spin the turbo better.
Other theories have said that it depends on your headers, if you have a good flowing header that the exhaust duration should be greater then the
intake, if you have an inefficiant header that the exhaust duration should be lower then the intake duration. If you have a good intake and header set up they should be equal.
Id like to see specific testing so there could be definate answers.
should i go witha twin or single
either or i dont beleive in performance that it matters. As long as the exhaust to and from the turbo chager(s) are of equal effiency both will spool the same (depending on the selection of the turbos) and make similair power if the right turbos are choosen.
if buyng a kit, choose the one that will fits your needs.
if building your own, the things that should be the desiding factor should be packaging, ease of being albe to work on it, cost, availabilty, weight.
Note alot of race classes twins are outlawed. And most of the realy heavy hitters are using a BIG single.
Most turbo companies say a twin is better for the street for good spool up, but the singles are more efficient on the top end with regards to racing.
some more reading, also talks about compond charging
http://www.hotrod.com/techarticles/e...bo/index2.html What intercooler should i go with
you have two choices in IC's Air to water or air to air
which one is right for you.
generally people use aire to air for the street and air to water for the track.
with the A2W IC you can put ice in the water box you can get the IAT down below ambiant temperature. Member testing shows that A2W ic's with just water works well on the street.
A2A is a very simple design. With a properly sized core it will work well and generally be less expensive then a A2W. It will also do a good job on the street or track if properly sized
Turbo FAQ 
