I searched and came up witih mixed results, so here it is: I am going to get a hybrid through BNR (I'm probably going to get a stage 3). I am going to buy a blown turbo and send it off to be rebuilt so I can keep the current one on my car while I am waiting. I currently have an s4 turbo. So for max power purposes, which is better an s4 or s5 turbo?

 

Personally I would say the S5.
if you look at the BNR website,they list the Prices,and the S5 is a little cheaper to Build up then the S4 is.
I just got my Stage 3 Installed.i am still tinkering with it.
I ran into a slight problem.The Old stock turbo inlet is smaller than the NEW mouth on the turbo( going to the AFM) so I need to find some kind of setup to attach from Turbo to AFM to filter.

 

get the s5 turbo for the perpose of it being cheaper, the s5 is a better turbo than the s4 but seeing as how your sending it to BNR it doesn't really matter perfomance wise what turbo you get

for both of you guys to solve that problem if you do not have access to a welder, get the corksport turbo inlet pipe, its larger and it uses couplers so you can get the correct size for the mouth on your turbo.

 

S5 turbo > S4. Misterstyx, you can use whatever size the inlet piping is, and run a reducer on the afm to the custom pipe. (I cut up a honda intake pipe)

 

Ya,I am figuring it out "slowly"..haha.I gotta order couplers.Why Ottawa doesn't sell any is Beyond me!
I got the aftermarket E-Fan in the road too.so that makes space a little limited.
I got an idea to get a Pipe made consisting of the IC pipes so that I can come out of the Turbo go 90 degrees and then Straight UP(another 90) to place a Big *** K&N filter on there.Ultimately it will look like a Carb style Setup in the corner of the car..lol!

 

My main question about the power was in reference to the s4's having the twin scroll. From what I read it can be a bit of a bottleneck, but I didn't see much concrete on it. I know about the s5's being cheaper, which was my initial motivation for investigating it. The problem is there is a dirt cheap s4 turbo for sale right now, while with the s5 I would also have to get a manifold, which kinda offsets the cost savings...

Also, I am running a haltech, so I already have 3" piping running to my filter, with a reducer to fit the stock turbo inlet.

To misterstyx69: they don't have autozones up there? I got my piping at an autozone, and they have 3" couplers there that come with a 2.5" reducer insert.

 

your not going to notice much of a difference in power if there is any. From stock to stock it would be the s5 turbo. But your sending it in to bnr to get redone and having the wastegate ported so there isn't going to be much of a difference. I say stay with the s4 so you don't have to swap your LIM, unless you plan in the future to go with a FD UIM.

 

The S5 wastegate and divided manifold design are both much better than the S4. The S4 wastegate only connects to one passageway within the turbine housing, which means the other half will still always have full exhaust gas volume trying to spin the wheel faster. You may find some claim the S4 turbine has a greater A/R, but in fact they're both the same. I've measured the port area and used linear approximation to get as close to the actual value as possible. S4 is basically 0.4 A/R + 0.6 A/R, and S5 is 0.5 A/R + 0.5 A/R.

There's no need to change the LIM if you were to use an S5 turbo on an S4 engine. It's a common upgrade. Also, if you give Brian an S4, I think he usually removes the twin scroll flapper. So low-end spool will suffer on the S4 hybrid, while the S5 version would still have the divided manifold benefit.

 

You can use a s5 turbo/manifold with a s4 Low IM Right? To clarify for everyone...

 

That's not what I said. I was responding to the post above that suggested you would need to change the LIM. You don't.

 

Thats what I thought and I was pointing^^ to the guy above you RR88. lol

 

S4 is the turbo to have for peak power, S5 for response.

 

So maybe I am still a little confused on how the system works, but isn't the twin-scroll mechanism in the manifold? If so, how can BNR remove it?

Do you have any basis for this in a hybrid setting? At this point its mostly about manifold design anyway....

 

I wouldn't think so. It's better to still have the housing divided even at high rpm's and peak power. If it wasn't then why is it that the majority of the people are running divided manifolds with divided turbos, and still make 500+whp

Also less turbulence to the turbine.


The twin scroll system is on the turbo manifold for s4 and controlled by pressure, reach that and it opens. Then reach another pressure point then the wastegate opens up. So you have 2 actuators, one on the turbo one on the manifold.

The twin scroll set up on a S5 is already built into the turbine housing. Which is divided...

 

go with a hole set from a dodge . there huuuuuuege

 

thats dany tanner from full house

 

Screw that, get one from a diesel locomotive.
http://www.bobnorwood.com/Un-Salted%...2012-Power.htm
Although that one is technically a supercharger, but at 60 pounds of boost who cares!

 

^^ That's tittys.

 

There is such a thing as TOO big.

I want to do some more looking into the variations between the s4 and s5. I was always under the impression the s5 was free-er flowing on the exhaust side.

I blew my damn aftermarket budget to hell so i'm shopping for oem used stuff now.....

 

It is free-er and better then s4 set up. Bigger wastegate, divided housing. But noooo, never too big. Never...