turbo exh mainifold design

[4gpwr]

I want to dicuss how diffrent turbo exh mainifolds behave log style mainfolds ,6boost style merge collectors ,starderd manifolds and others.How these manifolds work with external gates compared to internal,if their is a better mainfold suited for a external gate applacation and what about pipe size on a twincam would it be better to run a pipe close to the port size or go smaller merging two smaller pipes .How turbo manifolds affect lag and how hard the turbo hits .What about length and pressure drops and merging collectors.

[benny]

most common rule is runners the same size as ports, going to small will mean restriction up in the rev range, going too big means laggy as hell..

external wastegate over internal . full stop. .. better control, better flow, yada yada.

log vs buncho bananas vs octopus design:- the best no idea, but its all about flow if the spent gasses can fly throught it at all revs then its a good one :)


just noticed who's thread it is... so now your going to tell me i'm wrong and how it should all work and how much of a dumbass i really am???

[redzone]

keep pipe size same as port size. keep exhaust putts seperate until just before the turbo. build a nice flowing collector, aiming the putts at the exhaust housing in the correct fashion. build it from at least 3mm material. if adding an external gate feed, do it so putts from all exhaust runners can exit through there easily. try and achieve equal length if possible.

those are the golden rules.

[TomVR4]

what is the reason for using equal length runners?

[redzone]

timing of the exhaust putts is equalised between cylinders so the turbo receives pulses evenly promoting better spool.

[OLD FART]

My understanding is that always keep runners same size as ports and the lengths as equal as possible so the exhaust pulses are evenly spaced .Short runners = more power high in the rev range and longer ones give more torque but not quite as much power
Naturally all bends should be as smooth and flowing as space permits and the entry to the turbo should be as straight as possible using a merge collector like 6 BOOST ( do a search and it all will become clear as crystall )

[4gpwr]

With the port size on a vr4 head it is a preety big pipe that comes to the closest size of the port and i have noticed that aftermarket mainifolds the pipes seam to be flared out to meet the port size it seems to be a hard thing to do with steam pipe .I could buy a merge collector like a 6boost but the pipes only come a size smaller than the port size pipes but the issue with that merge collector to get the angle and size for the waste gate port right .If i made a log style mainfold it would save me alot of space and would be easy to get the waste gate port angle feed from the eng.Some people i have spoke to say a log manifold gives a harder hit of boost claiming that there is less area to fill up to minimise lag and less bends to minimise pressure drop.6boost claim to give more top end pwr and to decrease lag by a couple of hundred of rpm.I still dont know which way to go.If i was realy keen i would make two diffrent maifolds and test.Maby I'll just flip a coin.

[Komeuppance]

"Equal lenght tubes : within 3%, 321 SS, 16 gage walls, large 3" radius mandrel bends, 1-3/4" OD tubes. "Burns Stainless" turbo double-slip collector. Runner lenghts determined by Burns Stainless X-design software for a power peak at 6000 RPM and a redline of 7000. "

"Almost forgot, while this model is a combined collector, the tube locations are optimized for true split pulse devided housings. This is for those with devided turbine housings. This technology is proven to increase lower boost efficency, and will decrease lag by 15% according to Garrett."

Designed for the G54B.

-Robert

[OLD FART]

"Equal lenght tubes : within 3%, 321 SS, 16 gage walls, large 3" radius mandrel bends, 1-3/4" OD tubes. "Burns Stainless" turbo double-slip collector. Runner lenghts determined by Burns Stainless X-design software for a power peak at 6000 RPM and a redline of 7000. "

"Almost forgot, while this model is a combined collector, the tube locations are optimized for true split pulse devided housings. This is for those with devided turbine housings. This technology is proven to increase lower boost efficency, and will decrease lag by 15% according to Garrett."

Designed for the G54B.

-Robert

Great looking header design & workmanship with a nice merge collector :beer

[WidebodyWoody]

Looks like a FIP intake sitting there. Did they start making exh mani's too?

[4gpwr]

Steam pipe is the way i want to go, Ever seen all the cracked stainless exh manifolds at a drift meet ,also steam pipes seem to keep heat in. Thick wall stainless( at least 3mm ) bends is about $80 each last i checked.Steam pipe bends from a plumer supply shop are under $10

[Komeuppance]

Nope it's Chad's...

http://www.starquestclub.com/forum/inde ... opic=51703

[OLD FART]

With the port size on a vr4 head it is a preety big pipe that comes to the closest size of the port and i have noticed that aftermarket mainifolds the pipes seam to be flared out to meet the port size it seems to be a hard thing to do with steam pipe .I could buy a merge collector like a 6boost but the pipes only come a size smaller than the port size pipes but the issue with that merge collector to get the angle and size for the waste gate port right .If i made a log style mainfold it would save me alot of space and would be easy to get the waste gate port angle feed from the eng.Some people i have spoke to say a log manifold gives a harder hit of boost claiming that there is less area to fill up to minimise lag and less bends to minimise pressure drop.6boost claim to give more top end pwr and to decrease lag by a couple of hundred of rpm.I still dont know which way to go.If i was realy keen i would make two diffrent maifolds and test.Maby I'll just flip a coin.

Everything in life is a compromise the same with the design of manifolds :(
But a log type manifold would be my last choice due to the poor blending of the runners My personal choice would be a long runner design like the Merican one shown but in steam pipe & HPC coated to keep the heat loss minimal & thus keep gas speed high to help the boost to spool earlier
Any experienced manifold frabricator can make a merge collector in the runner size you select

[cheaterparts]

With the port size on a vr4 head it is a preety big pipe that comes to the closest size of the port and i have noticed that aftermarket mainifolds the pipes seam to be flared out to meet the port size it seems to be a hard thing to do with steam pipe .

Everything in life is a compromise the same with the design of manifolds :(
But a log type manifold would be my last choice due to the poor blending of the runners My personal choice would be a long runner design like the Merican one shown but in steam pipe & HPC coated to keep the heat loss minimal & thus keep gas speed high to help the boost to spool earlier
Any experienced manifold fabricator can make a merge collector in the runner size you select

My vote is for sep runners and if you wont to go with steam pipe whats the problem with flairing the ends to fit the port shape
just like the blacksmiths of old use some heat, steel is quite easy to work with when its heated bright red

HPC is great ,but is a bugger to weld any cracks at a later date so make sure its glued together properly