BOOST Taper QUESTION.
Dec 21, 2011, 09:26 AM
#1
BOOST Taper QUESTION.
Hey guys gotta question maybe someone can help me in answering it.
im drivin a ix se trim with some basic bolt ons on stock turbo.. mods are
perrin complete turbo intake and filter,
o2 housing
test pipe
short rt uicp
and lp2 licp.
forge 25lb wastegate actuator.
forge rs recirc bov.
and some other mods to support some more boost and tuning so pretty decently unrestricted as far as flow.
HERES MY QUESTION.. i kno this is in the design of the turbine housing we all kno and experience the boost taper effect. Im trying to get my setup and tune to hold 25psi without the taper. .. is this possible with the stock turbo design? ... im not trying to run 30lbs boost and im not interested in spiking that much either because i kno 25 is pretty close to max efficiency. but i want to run 25 and hold 25 to redline if possible. jw what the max anyone has held with stock turbo and similar mods.
any info would help thanks all..
im drivin a ix se trim with some basic bolt ons on stock turbo.. mods are
perrin complete turbo intake and filter,
o2 housing
test pipe
short rt uicp
and lp2 licp.
forge 25lb wastegate actuator.
forge rs recirc bov.
and some other mods to support some more boost and tuning so pretty decently unrestricted as far as flow.
HERES MY QUESTION.. i kno this is in the design of the turbine housing we all kno and experience the boost taper effect. Im trying to get my setup and tune to hold 25psi without the taper. .. is this possible with the stock turbo design? ... im not trying to run 30lbs boost and im not interested in spiking that much either because i kno 25 is pretty close to max efficiency. but i want to run 25 and hold 25 to redline if possible. jw what the max anyone has held with stock turbo and similar mods.
any info would help thanks all..
Dec 21, 2011, 09:56 AM
#3
haha thats probably my fault< i kno its just a shotty needle type local parts type mbc that my friend gave me to turn up the boost a couple pounds which i havent really done yet. its holdin 18.
def been needing to get a hallman or some better performing controler been looking at them just havent gotten around to it.
that sounds a little too easy though. iv heard the taper is caused by something to do with the design of the housing or wastgate? idk whats true or not. just trying to figure out facts ya kno and thanks for the input keep em coming.
Dec 21, 2011, 01:11 PM
#6
Dec 21, 2011, 01:15 PM
#7
It would be nice to get my setup to run 25 and hold that till redline.
Thanks for the headsup
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Dec 21, 2011, 01:20 PM
#8
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Lol my mod list up top says I have a forge piston type waste gate actuator I have a spring kit and right now it has a 25lb spring in it. And i kno a lot about the fp green and that's my turbo of choice just as soon as I can afford the 1700 price tag. But for right now I am able to get some more power off my stock snail for a lot cheaper so that's what I'm looking to do and thanks for the reply
Dec 21, 2011, 02:46 PM
#11
go back to the stock exhaust and you should have more than 26 no problem.
The less restriction you have the less boost your going to hold up top, boost is air pressure built up from air NOT going into the engine, so if the engine breathes better it will consume more air...and as such you'll make less boost. Obviously this can be overcome to a point by adjusting the boost controller etc but once its fully closed and the turbo cannot physically produce more boost,....your done.
I can hold 23.5 psi at 7000rpm with my mods, thats after peaking at 26. When I install cams I'm sure I will taper even more, but I'll be making more power so I don't care.
The less restriction you have the less boost your going to hold up top, boost is air pressure built up from air NOT going into the engine, so if the engine breathes better it will consume more air...and as such you'll make less boost. Obviously this can be overcome to a point by adjusting the boost controller etc but once its fully closed and the turbo cannot physically produce more boost,....your done.
I can hold 23.5 psi at 7000rpm with my mods, thats after peaking at 26. When I install cams I'm sure I will taper even more, but I'll be making more power so I don't care.
Last edited by akeric; Dec 21, 2011 at 02:50 PM.
Dec 21, 2011, 02:53 PM
#12
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my tuner? idk 3rd and 4th hold all the way. spikes at 27 then sits at 26 the whole way. 5th has a little bit of a boost taper. oh and a buschur inline mbc good stuff
Dec 21, 2011, 07:05 PM
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go back to the stock exhaust and you should have more than 26....The less restriction you have the less boost your going to hold up top, boost is air pressure built up from air NOT going into the engine.... if the engine breathes better it will consume more air...and as such you'll make less boost. Obviously this can be overcome to a point by adjusting the boost controller etc but once its fully closed and the turbo cannot physically produce more boost,....your done......
Last edited by sparky; Dec 21, 2011 at 07:10 PM.
Dec 21, 2011, 07:14 PM
#15
Is there any specific reason you want to hold 25 all the way to redline? 25 psi at peak torque is one thing, but 25 at 6k+ rpm is out of the turbo efficiency range, you'd likely make more (consistent!) power by allowing the boost to tapper and running more timing instead.