69-chvl

iTrader: (11)

So I'm beginning to hook up this s475 t4 on my 5.3, and I'm noticing how small the inlets are compared to the hot pipes!!!!! To be honest, a stinking 1.75" pipe fits the best in each inlet. A 2.125 can be sorta forced in each side, but really necked down. No way a 2.25 or 2.5" pipe is getting in those holes. I measured the Ls3 Camaro manifolds I'm using, and those suckers neck down at the flange to ~2.17. I can't help but think the 2.125 pipe forced to fit the t4 flange isnt going to be a restriction, but maybe that's the whole point of a divided housing?


Is it worth trying utilizing this? Looking for snappy street response, so I was going to try and use this setup along with 2 w/g's. Or, am I spiltting hairs with this deal?

HexenLord

Why 2 waste gates?

HexenLord

Never mind I reread your post. Why are you separating the cylinders? Trying to take advantage if the divided housing for max power or spool? If you're after spool just use a 4-1 merge and spool valve on a divided flange. Cheaper and less hassle.

ls1curt

iTrader: (31)

I would definitely do 2" hotpipes either way. Not only will it make it easier to merge in to the flange, but you will also have instant boost. 2" is good if your not looking to make more than a 1000hp at the wheels.

Camaro9969

iTrader: (12)

You should DEF do twin scroll you will have boost very quickly also run 2 gates its more efficient and will look way nicer than merging the two together.it will take a little more time to make but it will be worth it!

Sarg

iTrader: (6)

There. Was a big long discussion on this not long ago where people were using twin 2.25 pipe to over 1500 hp. I think with a t4 flange you will be fine with the 2.125 pipe or probably even 2" for that matter. You could always use 2.25 and neck it down to 2.125 right before they enter.

69-chvl

iTrader: (11)

Guys think its worth the hassle to run the divison? There really just isnt a whole lot of definitive info out there in terms of the benes/neg's

Camaro9969

iTrader: (12)

Yes I think people don't run it as often because its more work. If Borg Warner made it that way there must be a reason. Fwiw my s480 spools at 3100 (and these turbos people call laggy) and my id is like 2.6" converter timing afr and motor are more important factors in spool up than pipe diameter

Sarg

iTrader: (6)

I agree, and if you look at it, more and more OEMs are going twinscroll. Evos, Subaru, heck some have twin twinscrolls!

69-chvl

iTrader: (11)

Thing is, there's talk about how certain cylinders should be feeding each side of the housing, and there's no easy way to do that with our junk. Hopefully the benefit is worthwhile by just running each bank to each side.

Sarg

iTrader: (6)

In a perfect world, sure, but the difference in a couple milliseconds I do not believe is going to make a huge difference. The fact that you are hitting 2 different areas of the turbo wheel should be just fine. Crossing over cylinders from different banks and all would be a HUGE logistical pain. It will be very close to ideal as 1 bank per scroll.

69-chvl

iTrader: (11)

Sarg, with the recent video you and Demah posted of your engines idling, I couldnt help but notice how "well" your turbos were spinning at idle. In my amerature (sp?) mind, I would think your turbos are going to be responsive.

My last turbo venture was a totally stock '03 LQ4 with the same s475 t4 1.10 83/74, and it had the divided deal. I just used truck manifolds and 2.25" merged to a single 3" pipe to the t4 inlet. I did not divide it. The turbo wouldnt spin at idle, or just barley spin. Wonder if something was amiss? I thought the turbo was actually pretty responsive for the short time I ran it. But now that the engine I'm running has 40 less cubes, I want to do what I can to keep it peppy. If this engine ever blows, I will likely go 6.0 again.

Camaro9969

iTrader: (12)

Thats a little strange it wouldnt spin at idle. Was it a new turbo? Did you have exhaust leaks? You can see in this video before it starts up the turbo is spinning.

69-chvl

iTrader: (11)

That spins pretty nice!

new turbo, tight exhaust system. Oiling was also good. Maybe the aftermarket cams drive the turbos better even at idle??

Preston99WS6

iTrader: (7)

There is a lot of truth to your question, also Denmah's 80mm is the vsracing version and has a smaller turbine wheel than the BW units but it does sound sick.

Sarg

iTrader: (6)

Haha, My secret is MONSTER 2.5 inch tubes that are sized way to big and will apparently make the turbo unresponsive mated to leaky chinese v-band flanges (never again)

But in all honesty I have a pretty darn large T6 turbo with the 92mm turbine and a 1.10 AR turbine housing. I think the cam plays a role as well as the 92mm turbine. That is supposedly one of the latest turbine wheel designs from BW. We will see, but if a 6.0 can make one spool up with a larger 96mm turbine by 3200 rpms, I have no doubt I will be in it by no later than 3800-4000 rpms. But I guess we will see!

LilJohn

A borg engineer told us that banking a twin scroll could be worth 15% in the middle at a cost of 1-2% up top.

As far as you thoughts on the aftermarket cams.. keep digging. Even at idle what do think is happening if the exhaust valve is getting opened 10-15 degrees earlier? What do you think is happening if the cam has7-10 degrees of overlap at .050 versus -22.5???

Keep asking questions you are on the right path. And 2 inch pipe for you would be enough.

69-chvl

iTrader: (11)

Thanks John

Sarg

iTrader: (6)

Honestly I think a nice schedule 10 2 inch pipe would work great! Inside diameter of 2.137 and it is thick wall stuff that is cheap and retains heat wonderfully!

69-chvl

iTrader: (11)

Do you guys think there's better exhaust regulation using one or 2 wastegates??