I building a ls/v turbo and now i'm interested in know what will the difference be if i went with a 38mm wastegate compared to a 44mm? the turbo is a gt35r on a top mount mani fully built 2.0 ls/v would going with the 38 hurt me or be fine? will the 44 be better?

 

44 would be better.

 

the 38 is gonna have some boost spike. one of my customers had a PT70 turbo on a 38mm gate w/ a 9 lb spring. the car was seeing 15-17 psi. we put a 44mm manifold and gate and also a 12lb spring and now the car was only spiking to 15 psi

on my 1.8LS/VTEC with a 44mm gate and 9lb spring, 44mm gate, im seeing 10 psi.... and occasionally 11 psi

 

What type of manifold are you running?

How much boost are you planning on running?

 

Run a 44mm, you will have creep issues with a 38mm on that setup.

 

I am almost in the postion but i have already bought the 38mm and i already bought the topmount with a 38mm flange, i am running a gt35r also on a fully built gsr bottom end, I if i just run 12 psi with a boost controller will this work or what will most likely happen?

 

I am running the 38mm on a ramhorn with a sc61 which is similar with no spikes?I am also running 12 and 18 pounds of boost.I am also running a stroked b16 which id a little under 2.0.

 

You DEFINETELY want to run the 44mm if you are running a gt35r. You'll have one hell of a time controlling low boost using a 38mm wg.

 

lol wat is considered to be low boost with that turbo???

 

yeah I think im starting to realize that as well. My 35-38mm gate has a 7.8 spring in it and im floating all over 10-11psi. You have to controll it with pedal pressure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ProjectBoosted &raquo;</TD></TR><TR><TD CLASS="quote">I am almost in the postion but i have already bought the 38mm and i already bought the topmount with a 38mm flange, i am running a gt35r also on a fully built gsr bottom end, I if i just run 12 psi with a boost controller will this work or what will most likely happen?</TD></TR></TABLE>


if u wanna run 12 psi daily, then u should get like a 7-8 lb spring in the gate

 

Its all relevant to the manifold, wastegate placement and turbine housing. If everything is really effiecent you will be able to run the 38mm without a problem, if the turbo setup is not efficent then you might need to go to a 44mm as a "band aid".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by miller &raquo;</TD></TR><TR><TD CLASS="quote">Its all relevant to the manifold, wastegate placement and turbine housing. If everything is really effiecent you will be able to run the 38mm without a problem, if the turbo setup is not efficent then you might need to go to a 44mm as a "band aid".

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Very true... I worked with one set-up that ran the full-race ramhorn style manifold with the tial 44mm wastegate. We even had an issue with that set-up making 3-4psi more than the actual rating of the spring. And as you guys know... full-race is one of the 'better' designed manifolds. It was pre-tear drop design.

 

if hes not going to have a low boost setting than the 38 will be fine.

With a properly designed mani, i would say it will be able to hold 12-14PSI fine.

If ur not going to a have more than 1 stage to ur boost settings, and ur aiming for higher power(built motor) than the 38 will be good, just dont try to have a small PSI and be pissed when it doesnt hold.

 

Your wastegate sizes should be determined by your turbo size and amount boost you are going to run.

In order to maintain a constant boost level the wastegate has to be able to divert enough exhaust away from the turbin to keep the wheel speed down.

I think with the 35R and staying above 12PSI the 38mm will be fine. I would say 15psi to really be safe.

 

well its going to be a peakboost topmount manifold.... and the motor will be sleeved,forged pistons,forged rods,etc. I plan on running at least 20 lbs this car isnt a daily and will on see really nice weekends and some track days

 

well if its not going to see small boost then the smaller gate is fine.

Its when u have traction issues, and u want to turn it down from 550HP to get going before 4th gear thats going to be a probleme.

 

Thanks for the relpys...