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Waste Gate Choice for 500whp +

Posted: Tue Aug 13, 2013 10:12 pm
by S14wayz
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"

Re: Waste Gate Choice for 500whp +

Posted: Fri Aug 16, 2013 12:02 am
by denty95
im using a 38mm and im shooting for over 500

Re: Waste Gate Choice for 500whp +

Posted: Fri Aug 16, 2013 7:32 am
by wannabethestig
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.

Re: Waste Gate Choice for 500whp +

Posted: Mon Dec 14, 2015 8:09 am
by rn240sx
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…

Re: Waste Gate Choice for 500whp +

Posted: Mon Dec 14, 2015 6:49 pm
by ViperGT
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.

Re: Waste Gate Choice for 500whp +

Posted: Mon Dec 21, 2015 7:19 am
by beercandrifter
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