boostedsohchatch

I know i am a nOOb and everyone is gonna tell me to search, but i did and still got a question. I was wondering the difference between turbos if they both are pushing 5psi. Does it make a difference the size and trim of the turbo? My friend says 5psi is 5psi no matter what and i know there is a difference. Basically the difference between greddy and drag turbo kits. The difference between the tdh-05 and the t3/t04 turbo. If the boost isnt high, will hp numbers really be different. Thanks for the help!

stierhund

yes it can make a difference, turbo a/r ratios determine how well they can flow in cfm's

if they both are pushing 5psi at the same rpms then they should be pretty well equal in size, however if they are different size turbos it will take more/less exhaust to produce enough airflow to pressurize the intake air

there are so many factors to that... manifold, charge pipe size, etc

USDM 4G VTEC

CFM

the volume of the air

u can blow 5 psi air thru a straw and 5 psi thru a 3 in pipe... it takes a lot more volume to do same work on both

now they might both be pushing ssame psi, but at differents speeds.... wich might be a factor on when , and what rpm they can hold of pike the boost

boostedsohchatch

are you saying that on one turbo the motor is more stressed by pushind more exhaust in order to keep it at 5 punds... also the diference in turbos really wouldnbt be that much would it?

superstud

it's not stress on the motor at all. the biggest difference is the size of the compressor wheel (trim). generally (ie. not always the case), a bigger compressor will flow more air at a given pressure (psi). basically that means that with a bigger turbo you can make more power at a given psi than with a smaller turbo.
make sense?

boostedsohchatch

When looking for the a turbo, i get confused with all of the numbers like the a/r. Could someone give a break down of all the numbers and what they mean. Please!?!

Ri5e

A/R is just the cross sectional area of the compressor outlet divided by it's corresponding radius (the distance from the center of the turbine to center of where you measured the cross sectional area )

sharkcohen

Awesome, I didn't know that, always wondered.

Cramerox

Basically yes both turbos can supply 5 psi. But the larger turbo will put more air in the engine at 5psi. so more air more power. Numbers are not accurate im just making it up....
so lets say the small turbo blows 100 cfm at 5psi, a larger turbo will blow 150cfm at 5psi.

igotyofire

but does A/R stand for a word or anything and is it used as an abbreviation?

JalopySiR

There are differences in turbos, and then there are differenced in turbo Kits. Let's start with turbos first. You'll find that most people on this site, and possibly the world are using T3/T4s, they are upgradeable, and have alot of parts made to be used with them i.e. downpipes, manifolds, v-band adapters, etc...

Now among different turbo families, there are different "sized" turbos. There are many things that determine size. The compressor housing a/r, the turbine housing a/r, and the trim of the compressor and turbine wheels. Lets' start with the turbine housing a/r. This is pretty much what determines your spool vs. top end power. Usually the larger the a/r the laggier the spool, with more top end power. Smaller numbers spool faster, but tend to fall off in the upper RPMs, esp. on high flowing turbo Honda engines.

The trick is figuring out what you want, then going from there. All out drag? response? Balance? Balance being the trickiest. This is why it is so important to pick the right turbo for your car.

As for compressors and wheels, usually I have found you'll want the biggest one you can use that fit's what you want the turbo to do. This is what compressor maps are for. Also, with hondas, you have to worry about room in front of the engine bay for the actual compressor housing. Larger turbos at 5psi usually make more power than smaller turbos at 5psi. They are both pushing 5psi, but which one is doing so more efficiently, creating less heat. Which turbine housing is flowing more exhaust?

Then there are the auxillaries, the downpipe, the exhaust, the management. There will all affect how much HP that 5PSI is making.

This is where turbo kits come into play. They generally have what they think you need to slap a turbo on a car. There are big differences between kits. My brother had the Greddy kit, and I built my own with a T28. Having done the 2 options other than T3/T4, take my advice. Go T3/T4.

It's much easier to upgrade when you want more power later. There is just plain More More More. The Greddy kit is GREAT if you'll be happy with it. It does what it does very reliably, but that's it. It a BITCH to upgrade the Greddy kit, trust me. I think I trailed opff there a bit, sorry. HTH.

Cliffs: 5psi is 5psi, but 5psi on one turbo(or kit) does not equal the HP another turbo(or kit) at 5psi will make.

boostn420

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by igotyofire &raquo;</TD></TR><TR><TD CLASS="quote">but does A/R stand for a word or anything and is it used as an abbreviation?</TD></TR></TABLE>

Air/Ratio

JalopySiR

Close. I beleive it's area ratio. Having to do with the "area" inside the housings.

igotyofire

i see where that pic came from, http://www.hotrod.com/techarti...turbo/
good article

JonnyCoupe

That diagram shows Area and Radius...

surely its not to hard to realise A/R is Area/Radius and A/R is infact a ratio in its own sense.

kpt4321

https://honda-tech.com/zerothread?id=710270

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stierhund &raquo;</TD></TR><TR><TD CLASS="quote">yes it can make a difference, turbo a/r ratios determine how well they can flow in cfm's
</TD></TR></TABLE>

Wrong. While a larger A/R will generally mean that a turbo has the capacity to flow more, it's not nearly that simple. A smaller A/R turbo could outflow a larger A/R turbo, depending on the circumstances.