Waste Gate Choice for 500whp +

Basic tech questions such as future setups, different turbo kits, car diagnosis, etc
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S14wayz
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Waste Gate Choice for 500whp +

Post by S14wayz » Tue Aug 13, 2013 10:12 pm

So may seem like a stupid question but I'm in the middle of ordering parts mani/turbo/w/g and blow-off and need some help on wastegate size (I searched but no solid info). I'm probably going with a t3 6262 Precision turbo .82 A/R Vband and DOC manifold which offer 38mm flange, MVS and MVR.
So based on that I got to pick between 38 & 44mm and I assume 44mm wastegate should be used for my application but not sure.

Found one post on another forum but not sure how accurate it is.

"Wastegate size for power level...
32mm up to 400hp
38mm up to 500hp
42mm up to 900hp
51mm up to 1400hp"
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denty95
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Re: Waste Gate Choice for 500whp +

Post by denty95 » Fri Aug 16, 2013 12:02 am

im using a 38mm and im shooting for over 500
96 s14
arias 8.8 pistons, brian crower rods, acl bearings, brian crower stage 2 cams, cx racing front mount turbo manifold, gt35r, 850cc injectors, apexi dual n1, greddy profec-II, xcessive intake, AEM EMS, cometic hg.

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Re: Waste Gate Choice for 500whp +

Post by wannabethestig » Fri Aug 16, 2013 7:32 am

I would think the size of the turbo and housing, amount of boost, manifold design, exhaust size and even the boost controller and solenoid would also contribute to the selection.
My wife "haven't you spent enough time and money on that car yet?" my answer "no"

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rn240sx
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Re: Waste Gate Choice for 500whp +

Post by rn240sx » Mon Dec 14, 2015 8:09 am

S14wayz wrote:"Wastegate size for power level...
32mm up to 400hp
38mm up to 500hp
42mm up to 900hp
51mm up to 1400hp"
Its actually the opposite… The Lower the boost/hp level the larger the wastegate needed … The higher boost/hp level the smaller wastegate needed.. Here is how it works…
When your pushing high boost/ hi hp MOST of that exhaust is being driven thru the turbo and down pipe (hence the hp boost & hi hp) and minimal thru the wastegate so a small wastegate is ok for high hp boost/hp setups… Think about it… high boost/high hp means the turbo is getting MORE of the exhaust gas...
On low boost/ low hp setups, MOST of the exhaust gas will route thru the wastegate and the left over will go to the turbo (hence the low boost/ low hp) … This is when you need a large wastegate to allow the majority of the ex gas to flow thru it smoothly without any restriction…

I can tell you that i have a Tial 35mm wastegate and i have pushed 25 lbs and as little as 7 lbs and it works fine… it may be the smaller of the wastegates that they offer but it was large enough to flow that much ex gas and keep the motor solid at 7 lbs…!!!

And to prove my theory from the above explanation… When i pushed 25 lbs of boost… I NEVER heard that wastegate open up….. !!!!
When i pushed only 7 lbs… that wastegate would open and SCREAM bloody murder… YET hold 7 lbs solid…!!!


Don't let any sales idiot or some wannabe tech on a forum tell you that you need a LARGE wastegate for high boost high hp setups… if they do, they don't know what they are talking about…

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Re: Waste Gate Choice for 500whp +

Post by ViperGT » Mon Dec 14, 2015 6:49 pm

ive got an mv-r on a custom log mani, had a t25 on it and an hx35 now (maxed out because of manifold flow at about 17psi) with the mv-r ive been able to run 4psi of boost on a small spring. most people run more than this but when i was first tuning i was iffy but iit did the job.
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
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beercandrifter
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Re: Waste Gate Choice for 500whp +

Post by beercandrifter » Mon Dec 21, 2015 7:19 am

S14wayz wrote:So may seem like a stupid question but I'm in the middle of ordering parts mani/turbo/w/g and blow-off and need some help on wastegate size (I searched but no solid info). I'm probably going with a t3 6262 Precision turbo .82 A/R Vband and DOC manifold which offer 38mm flange, MVS and MVR.
So based on that I got to pick between 38 & 44mm and I assume 44mm wastegate should be used for my application but not sure.

Found one post on another forum but not sure how accurate it is.

"Wastegate size for power level...
32mm up to 400hp
38mm up to 500hp
42mm up to 900hp
51mm up to 1400hp"
Most people that run the 500+ range I have seen run the 42mm size
91 240sx Hatch: HomeBrwd
25psi hx35/8.8:1/264^2 cams/95lb injectors/Megasquirt 2/ka24de build **RIP**
T56/4.8 LSx/LS9 Cam/60lb injectors/comp 918 springs/Megasquirt 3/all custom wiring

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