Is this turbo the problem? BW S366
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
Is this turbo the problem? BW S366 6.0 /4l80e combo in '77 C30 crew cab dually. Goal was to make power early and build torque.
Turbo - BW S366
44mm WG
50mm BOV
80# Dekas
Finally got it on the dyno today (I wasn't there). Boost is uncontrollable. WG has a 6# spring. Manual boost controller taken out of the loop. Boost ran to 16# at one point at WOT.
Is this just too small a turbo for this setup or do I have other issues?
Turbo - BW S366
44mm WG
50mm BOV
80# Dekas
Finally got it on the dyno today (I wasn't there). Boost is uncontrollable. WG has a 6# spring. Manual boost controller taken out of the loop. Boost ran to 16# at one point at WOT.
Is this just too small a turbo for this setup or do I have other issues?
Last edited by 1936 LS1; Apr 25, 2020 at 09:29 PM.
On The Tree
Joined: Oct 2012
Posts: 171
Likes: 9
Idk man I had trouble controlling boost lower than 10 psi on my 5.3 with the wastegate right in the bend of my log manifold. All of the exhaust flows right into it. On a bigger 6.0 with a smaller turbine like the 73mm he has it would be amplified. I run a precision 46mm gate on mine
IE, if you want to make 6 PSI on a S366 you need to flow much more air through the wastegate than if you had an S480 with the 96mm turbine?
Though I agree that a 44mm gate should do it, if it's placed and actuated correctly. Do you have any picture of the setup?
What's the spring in the gate? A certain size motor has a given exhaust flow. People use 44mm gates 5.7, 6.0s, 383s with out issue. That's a small turbo but usually a big motor and small turbo means you won't make enough boost because you'll choke it out.
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
It spools instantly. I wanted it to come on early but this may be too early. This 66mm turbo is really the only deviation from a lot of tried and true recipes.
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Verdad Gallardo The wastegate tube is the tube going up towards the engine? That's doesn't look like good placement at all. You want it I'm the path of exhaust flow. Maybe it's just from the angle.
On The Tree
Joined: Oct 2012
Posts: 171
Likes: 9
Won';t you effectively need more wastegate witha smaller turbine than larger though?
IE, if you want to make 6 PSI on a S366 you need to flow much more air through the wastegate than if you had an S480 with the 96mm turbine?
Though I agree that a 44mm gate should do it, if it's placed and actuated correctly. Do you have any picture of the setup?
IE, if you want to make 6 PSI on a S366 you need to flow much more air through the wastegate than if you had an S480 with the 96mm turbine?
Though I agree that a 44mm gate should do it, if it's placed and actuated correctly. Do you have any picture of the setup?
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
1) 90 degrees off a hotside is lousy for WG mounting. I'd be more concerned about the angle than the size of the gate.
2)forget the controller. Run the vacuum line from the turbo to the side port of the WG directly. Start with this and see is boost is more controllable.
2)forget the controller. Run the vacuum line from the turbo to the side port of the WG directly. Start with this and see is boost is more controllable.
No surprise you're having trouble controlling boost. Get the controller out of there first of all and run spring only. If that doesn't fix it then you'll have to fix the wastegate tube regardless of staying the same size or stepping up in WG size.
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
This was the potential problem I expected, not TOO MUCH boost.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Gate takeoff doesn't look that bad at all. But yes, just throw a larger gate onto it, it's by far the easiest option.