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03OrangeSVT 12-25-2008 12:43 PM

Turbo AR's Q&A.....
I've been noticing when people ask about what size turbo's they need they alway ask "do I need a .50 ar or 64ar" and so on....

The AR is nothing more than the size of the exhaust houing.... not the power capabilities of the turbo itself.

When looking at how much power you want to make you need to look at PPM (air in pounds per minute of flow)... a really neat trick I've picked up on is 1 ppm is good for around 10hp (rating wise)

Example a a turbo that flows 35 PPM is capable of 350hp ... according to how they rate turbos.

After you figure out how much FLOW you need then you need to look at AR... a smaller ar (example a .50ar) will spool faster than say a larger (.86ar) BUT usually the smaller ar will peak then start to fall off powerwise, the larger ar may take a little longer to spool but it will make more top end power. Also you need to remember that the ar is also a restriction... all of your exhaust has to flow through it.

[:)][:)][:)][:)][:)][:)]* This is just some basic info you need to think about when looking for a turbo... there are also many other factors that come into play like the ratio between the hot side wheel and the cold side wheel.[:)][:)][:)][:)][:)][:)]*

Any questions I can help you guys with???

cwatson411 12-25-2008 12:54 PM

so what turbos would flow about 25-30PPM?

also, do you think that a turbo with those^ flow #s would spool relativaly early and not fall off at top end to much with an ar of about .50?

03OrangeSVT 12-25-2008 12:59 PM

I would look at turbos like the T3 super 60 or GT28r (depending on your choice of brands)

Personally I would go with a .64ar or maybe bigger... I've seen many dynos of the smaller ar and they all do the same.... they hit peak tq then immediatly start to fall off.

With a bigger ar you can hold the peak longer and when it does fall off it tends to do so at a slower rate.

cwatson411 12-25-2008 03:50 PM

cool, im just looking for a wider powerband

and it looks like thats the way to go

jerbear 07-28-2009 08:23 PM

What comes in Tom's DIY kit?

1turbofocus 07-28-2009 09:27 PM

John your opening a whole can or worms you dont really want to open

There is a reason that I dont give out many specs and help people choose turbos , It took me a long time to stop doing it , you really done want to go there


sporadic 07-29-2009 05:28 AM


Originally Posted by 1turbofocus (Post 2860639)
John your opening a whole can or worms you dont really want to open

There is a reason that I dont give out many specs and help people choose turbos , It took me a long time to stop doing it , you really done want to go there


That's what this forum is for is it not?

1turbofocus 07-29-2009 06:56 AM



kamilk 07-29-2009 07:36 AM


Originally Posted by 1turbofocus (Post 2861149)


WTF are you serious. tom i respect you but god damn whats the point of a forum if not to share information, help each other, and educate one another. thats how you build a community.

yea your going to get some annoying people that dont know what even a wastegate does but for the majority of people that want to learn the information should be accessable. teaching the focus community to inspire creativity and new ways of doing things.

damn your a tyrant.

1turbofocus 07-29-2009 09:17 AM

Thats all well and good , To say a t3 s60 stg3 turbo is what your need for your Focus isnt something that can come from reading a forum , The Zetec isnt like most engines in how it responds to boost

Teaching people what the diff numbers are and PPM is all well and good , but what if those # dont apply to the Focus they way they do other 4 cyl engines , so you learn a lot of this stuff , buy a turbo to find out it wont make the power you wanted , many will come back here and , well you guys said if this and this was here that this turbo would make the power I wanted

There may be 5 people on here that can read a turbo graph and maybe 2-3 that actually understand what there reading

Then you get into custom turbos that with the Zetec throw a lot of sence out the window , picking a turbo isnt something your going to learn from a forum it is like tuning and something that takes years of building boosted engines on a dyno to learn what the numbers mean and do

Then you get into HP ratings and those are commercial HP ratings # and have little to do with the actual HP the turbo will make from one build to another let alone one engine to another


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