Unfortunately it appears that way.

 

I have a T6 S480 on my HSP V1 kit. I used a t4-t6 spacer and made my own DP. I have posted to at least 2 other threads about this exact question over the last year. I have a BMR Turbo K and run 4" exhaust after my 5 to 4" reducer off the turbo. I also made a brace off the passenger side head. I also run a TH400

 

That is awesome. How much room did you have between the crank pull and radiator after the T6 went in? I'm worried about space. Also do you have a link to the spacer you used? Thanks!

 

 

I have tuned a T4 turbo kit on a 403cube iron block that used a factory header on one side and only a 2 inch cross over pipe. it had a t6 flange grafted onto the manifolds and an 82mm single T6 1.32 rear. was on E85.

it wasn't ideal and once we put some boost into it you could really see where the manifolds were holding it back.

that being said though it still went 970rwhp through a 5500rpm converter on 20psi.

it will certainly work. it wont be the most efficient nor will it flow the best but it will definitely work. if you start will very low boost as add 1 or 2 psi at a time the power graph, torque curve and boost pressure (and EGT data if you're Hollywood) will paint a clear picture of when its beginning to choke up

 

Alright. I understand your train of thought on that.

 

Is your S480 a twin scroll exhaust housing?
I had always heard that using an open flange with a twin scroll flange could cause it spool a little slower, I'm running a manual so spool time is important to me.
Can you provide some feedback?
Cheers!

 

twin scroll only works separately if the entire exhaust system is separated from one and other. 4 runner into one scroll with its own gate and 4 into the other with its own gate, a manifold that joins all runners at the turbo flange or has a single pre turbine gate port just allow the gas to pick the path of least resistance.

true twin scroll forces half the gas to exit via the tip of the turbine wheel traveling around the housing. the easiest path is past the center of the wheel and straight out. the gas forced to the tip of the turbine generate a greater torque on the wheel through mechanical advantage generating turbo RPM faster reducing lag

 

Thank you for the reply Luke, please indulge me.
I had a TC7868 turbo and when I looked at the inlet side of the turbine flange (T4) it had a dividing wall, my assumption was that this was twin scroll and that the hotside also needed to be divided to work as efficiently as possible.
Most T6 setups I see have a divided flange with each bank feeding each side.
Is that not twin scroll?
I wouldn't mind upgrading to a borg at some point but spool would need to be a critical point since my car is a manual and its a street car, not a track car.

 

yea the dividing wall makes it a twin scroll turbo. but with the exhaust gases all being combined together with a manifold that isn't separated for each scroll when the gas gets to the turbine housing it'll go through which ever scroll is of least resistance. which is the scroll that exist past the center of the turbine wheel with the shortest path through the housing.

once the turbo is on boost different story as there is so much gas flow both paths are of equal resistance.

but the idea of twin scroll for faster boost requires exhaust gas flowing past the turbine wheel tip generating a greater torque on it to build RPM faster. gas is no different to water in how it flows.

 

So then in theory a twin scroll turbo used on a merge style flange could have slow spooling / throttle response characteristics.
Hmmmm.

 

it will still be an improvement over open flange and housing. its still directing some gas at the turbine wheel tip. but marginal improvement only. this turbo has ample turbine flow capacity. but small frame twin scroll units are restricted in turbine flow compared to the same size unit with open flange.

you're not turbo charging a 2.5ltr jap engine. you have 5.7ltrs to get the turbo going,

I put greater value on efficient turbine flow at target power lever over reducing lag in a single turbo LS combo

 

https://ls1tech.com/forums/forced-in...ron-speed.html

post #11

if that merge collector is still completely separated into the turbo flange then that is a true split pulse system

 

Why use a T4 to T6 adapter flange...how about cutting off the T4 flange and welding on a T6 flange....? No more bottle neck.....

.

 

any pics of modifications