[drunkinmonkey]

darkpuppet,Oct 30 2009, 01:16 PM Wrote:

ZX3_2NV,Oct 30 2009, 10:00 AM Wrote:GO BIG OR GO HOME  ;) With the money your spending on the motor build it would be a waste to put in a smaller turbo.  Well if you don't belive me about spool ohh well increased airflow into the motor increses exit airflow incresing SPOOL.
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The problem with spool, is that until the turbo is spooled up, you don't get increased air inflow, you actually get decreased in-flow due to the backpressure introduced by the larger wheel.

Of course, spool also makes the STi daily driver friendly under 3,000 RPM, and a monster over 3k.

As for the size of the throttle body, throttle body sizes don't matter as much in forced induction... or turbos.

In the end, boost is a measure of the wasted air in your intake -- it's not a measure of power. Decrease backpressure, take in more air, increase HP, lower boost pressure.

due to the fact that exhaust gases exert more pressure on the turbo, you'll get more efficiency in decreasing the backpressure after the turbo than you would by putting a larger throttle body on.

In my opinion (and it's just that -- my opinion), a larger throttle body would be necessary if you found that your boost was rising and plateauing early at WOT, but not limited by the boost controller. This would mean 1 of two things -- you have excessive backpressure aft of the turbo, or a restriction in your intake -- and once you eliminate the backpressure issues after the turbo, and you're still having boost plateauing issues, then you need a bigger throttle body.

If you were going N/A .. you're engine isn't being force-fed air and needs to sip it through the straw... in which case you want a larger TB.

As for mechanical vs electric gauges -- Electronic gauges offer two distinct advantages -- you can often datalog off them easier, and if there's a leak, they don't leak into your cabin.

mechanical gauges are cheaper, but you can't datalog them like e-gauges, and if they get a leak, then you get that leak into your cabin -- which might be a safety concern when hot oil starts spraying into your interior.

But for basic functionality, they're both about equal.

Good luck with your project.. you're off to a good start.
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thanks for clearing this all up puppet..im getting my shop to do the acually swap and hooking all the lines up for the turbo and such they gave me a super good price to do the swap and run lines and such the acuall swap wont happen till aprilish as the car is gonna be in storage so this thread is gonna be pretty dry for a few month :( ill give you guys a heads up when it happens...im gonna try and stretch it out as much a s i can so the thread doesnt go to dry.....STAY TUNED