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2000 impeza 25Rs
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572 Posts
Discussion Starter · #1 ·
Im going to be buying a turbo legacy soon and need some help on parts and performance before I do any work on it. Like what are IHI turbos and what dose rotating a turbo do. What's dose the waste gate on a turbo do and why should do people put bigger ones on. Where is the best place to put a bov. What's the difference between recirculeting and non recirculeting bov. What do boost solinods do and can you put bigger ones on or swap them from another vehical. What are some on the saporting mods you need before upgrading the turbo. What is boost creep or boost spike. Sorry if im asking a lot but its my first turbo car and I wanna build it right.
 

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BRP ver5 RSTi, Beater Leggy
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HowStuffWorks.com

Seriously, lots of information about what you're asking is there. But if you have to ask basic of the basic stuff like that, I dunno if you're really ready to mod a turbo car yet.
 

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2015 STI Crystal White Pearl
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1,931 Posts
Im going to be buying a turbo legacy soon and need some help on parts and performance before I do any work on it. Like what are IHI turbos and what dose rotating a turbo do. What's dose the waste gate on a turbo do and why should do people put bigger ones on. Where is the best place to put a bov. What's the difference between recirculeting and non recirculeting bov. What do boost solinods do and can you put bigger ones on or swap them from another vehical. What are some on the saporting mods you need before upgrading the turbo. What is boost creep or boost spike. Sorry if im asking a lot but its my first turbo car and I wanna build it right.

that's alot of info to answer. here's a garrett turbo site for turbo 101, which explains the entire turbo system:

http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

IHI (Ishikawajima Harima Heavy Industries, Ltd.) turbos are japanese turbos found in various japanese cars, subaru for one. here are a bunch of IHI turbos found in past and current subarus:

http://www.rs25.com/forums/showthread.php?t=60874&highlight=vf+series+turbos

hope this helps.
 

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1998 Subaru Impreza RS - RBP
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1,762 Posts
The wastegate regulates what the turbo's pressure is set at.

If you have a top-mount intercooler the bov most likely attaches to it. If you have a front-mount, then it will go somewhere on the cold side of the intercooler piping.
A bov that recirculates is called a bypass valve and it puts the "blown off" air back into the intake. A non-recirculating one is called a blow-off valve and it releases the air instead of putting it back into the intake system. You can also buy a diverter valve which you can use to get the sounds of a bov and the functionality of a bpv.

(I'm not much on boost solenoids, so I'll let someone else cover that area.)

When upgrading a turbo, you should make sure you are going to have enough fuel getting to your engine. You may have to put in larger injectors, fuel pump, and/or a fuel pressure regulator. If you are going to upgrade a LOT of power, you will need to put in new internals: pistons/rods/bearings.

Boost creep is where your turbo pressure spikes up for a little bit and can cause damage to your motor...

Hope this helps in some way. There is a lot of information on this site, use the search link to find it. ;)

-Nick
 

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'00 RS w/ 05 STi swap
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Boost creep is where your turbo pressure spikes up for a little bit and can cause damage to your motor...
its actually the opposite - boost creep is when the wastegate opens too early and your boost will "taper off" towards the upper range of rpm. you will want an external wastegate to minimize boost creep. boost spike is what zeropunk is reffering to and boost spikes can destroy engines from overboosting (causes lean conditions or other stresses)
 

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2015 STI Crystal White Pearl
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its actually the opposite - boost creep is when the wastegate opens too early and your boost will "taper off" towards the upper range of rpm. you will want an external wastegate to minimize boost creep. boost spike is what zeropunk is reffering to and boost spikes can destroy engines from overboosting (causes lean conditions or other stresses)
boost creep is rising boost due to not enough exhaust bypassing the wastegate. for example, you're set for 13 psi, and when you floor it, you get a quick rise to 13 or 14 psi. but then as rpm's climb, the boost creeps higher and higher: 14, 15, 16, 17, etc. enlargening the wastegate hole or upgrading to a larger wastegate is the cure for boost creep. but too big of a wastegate can lead to spiking....

spiking is when your wastegate hole is large enough, but your actuator can is taking too long to fill with compressed air, so you *temporarily* overshoot your boost level. for example, you're set for 13 psi, and when you floor it it quickly rises to 16 psi, but then gradually drops downward towards 13 psi again.
 

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2000 impeza 25Rs
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572 Posts
Discussion Starter · #7 ·
Wow. Thanks guys for the info. Like I said this is my frist turbo car im building on my own. Do to a rescent move. I built some na motors up but not a whole lot a turbo engines. Ill keep searching the site for more info.

MOE
 

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1998 Subaru Impreza RS - RBP
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its actually the opposite - boost creep is when the wastegate opens too early and your boost will "taper off" towards the upper range of rpm. you will want an external wastegate to minimize boost creep. boost spike is what zeropunk is reffering to and boost spikes can destroy engines from overboosting (causes lean conditions or other stresses)
Thanks for the correction... meant boost spike :)
 
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