Turbo guys....38mm or 44mm wastegate on 5.3 build?
07-21-2011, 10:53 PM
#1
TECH Apprentice
Thread Starter
iTrader: (20)
Join Date: Jul 2009
Location: Liberal land
Posts: 390
Likes: 0
Received 0 Likes
on
0 Posts
Turbo guys....38mm or 44mm wastegate on 5.3 build? As the title states, I have a 5.3 build I'm doing in my 3rd gen trans am. The set up is a stock 5.3 bottom end, 317 heads w/ ARP head studs, LS6 cam and springs, and a turbonetics T76 turbo. I'm looking to run 12-14 PSI. I'll be going with all Tial components for wastegate and BOV....just curious if the tial 38mm wastegate will handle the job or if I should upgrade to the 44mm? I know that lower boost requires a bigger wastegate but I would think 12-14 PSI is on the higher side. Just looking for opinions. Thanks.
07-22-2011, 12:36 AM
#4
TECH Apprentice
Thread Starter
iTrader: (20)
Join Date: Jul 2009
Location: Liberal land
Posts: 390
Likes: 0
Received 0 Likes
on
0 Posts
Awesome....just what I wanted to hear. I may just opt for the bigger wastegate off the bat but in case I get into a money crunch and need to use it more wisely on another aspect of the build, at least I know a 38 will work. And to be honest, this car has been coming together for 4 years now. Should run this summer....but I doubt I'll be taking it apart or upgrading anything anytime soon unless the motor blows. Going from a 225 HP 305 to a 600+ HP 5.3 should hold me over plenty for a while! 
07-22-2011, 12:59 AM
#5
Go with the bigger one! Have you thought about going with the JGS wastegate and bov? There stuff seems to be a little better build than the tail. JGS is what I am using with my build. Check out my build thread https://ls1tech.com/forums/forced-in...-ky-turbo.html
Trending Topics
07-22-2011, 01:40 PM
#9
my TC76 would hold 6-7 lbs with my 38mm turbosmart, sometimes it would creep to 9-10 lbs when it was really cool out. I swapped to a Precision 76GTS and the 38mm gate will hit 15-16lbs in 3rd gear. If I leave the cutout closed it will stay around 7lbs. Get the new precision 46mm gate, $310-325, comes with a wide assortment of springs.
07-22-2011, 03:26 PM
#14
Also, (just as an FYI) a smaller gate isn't best for lower boost applications. The gates primary purpose is to divert exhaust gases away from the turbine wheel to keep the boost at X level. If you get too small of a gate you could potentially face boost creep issues and that is not a good thing on pump gas.
07-27-2011, 10:20 AM
#15
Staging Lane
Join Date: Sep 2008
Location: MI
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
07-27-2011, 01:58 PM
#16
I have the 38 Tial with an identical build.
I am running about 15 psi and the waste gate works perfect, no issues.
Your CR is going to be low though.
With the T76, you are not going to spool until 3000.
Right now, I spool at 2500 and that is with a T70.
But, on the bright side, get ready for some sick power!
I am running about 15 psi and the waste gate works perfect, no issues.
Your CR is going to be low though.
With the T76, you are not going to spool until 3000.
Right now, I spool at 2500 and that is with a T70.
But, on the bright side, get ready for some sick power!
07-27-2011, 08:36 PM
#17
On The Tree
Join Date: Jan 2007
Location: IL
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
just ordered 60mm let you know how it does
Last edited by LS1LT1CAM; 07-27-2011 at 08:41 PM.
12-30-2011, 07:52 PM
#20
I'll clarify.. Base wastegate size on the lowest amount of boost you want to run, and your displacement/turbo size...
IE
5.3 with T70, never going below 7 PSI, a 38 is fine.
6.0 with T76 (my combo) I used a 44mm TIAL, and don't expect to be able to go below 6-7lbs..
6.0 with 88mm, I'd use a PAIR of 44's, or a 60mm single.
408 with 91mm+, a pair of 50+mm wastegates.
The wastegate dictates how much exhaust you can "waste," to drop boost to an acceptable level. Say you have a 370CID motor with a t78... A 60mm wastegate could allow you to rev all day without making boost.. or regulate it down to 1-2psi.
A 50mm may get it down to 4 psi..
A 44mm probably wouldn't go below 8-9 psi..
A 38mm you might be able to regulate it down to 12 or so..
make sense?
Bigger motor = bigger wastegate..
Bigger turbo = bigger wastegate (not taking into account the A/R of the turbine housing, a 1.16 A/R would need less wastegate than say a .68, because it flows better, and turns the turbine slower.
IE
5.3 with T70, never going below 7 PSI, a 38 is fine.
6.0 with T76 (my combo) I used a 44mm TIAL, and don't expect to be able to go below 6-7lbs..
6.0 with 88mm, I'd use a PAIR of 44's, or a 60mm single.
408 with 91mm+, a pair of 50+mm wastegates.
The wastegate dictates how much exhaust you can "waste," to drop boost to an acceptable level. Say you have a 370CID motor with a t78... A 60mm wastegate could allow you to rev all day without making boost.. or regulate it down to 1-2psi.
A 50mm may get it down to 4 psi..
A 44mm probably wouldn't go below 8-9 psi..
A 38mm you might be able to regulate it down to 12 or so..
make sense?
Bigger motor = bigger wastegate..
Bigger turbo = bigger wastegate (not taking into account the A/R of the turbine housing, a 1.16 A/R would need less wastegate than say a .68, because it flows better, and turns the turbine slower.
The following users liked this post:
n2xlr8n66 (08-29-2021)