tubular exhaust manifold question??

[rpmvulocity]

i was wondering what's the big deal about a tubular manifold. i read around saying it's suppose to help build a better exhaust pressure for the turbo so that means a better spool up. but then what's the difference from a stainless steel tubular manifold from like a evoIII cast-iron ported manifold. does it really make a difference if u have a tubular compare to it.

 

[MNGSX]

99% of tubular manis are nothing but problems...

 

[rpmvulocity]

what are some of the problems?

 

[MNGSX]

cracks due to expansion and supporting the weight of the turbo...


The only way to make them last makes an expensive manifold.. Like $800. Use the more expensive ss alloys, a burns ss double slip turbo collector and a tripod to support the turbo from the block...


Get a ported 2g, evo or v2 SBR manifold instead..

BR ported 2G exhaust manifold

On a 8 second car... http://www.buschurracing.com/Conquest1.html

 

[rpmvulocity]

does this just go for dsm's...or any turbo applications for other manufactures vehicles? and what's the theory behind the tubular manifolds?

 

[MNGSX]

1. Turbo manifolds get really hot.. Metal expands and contracts. If it is welded and does not have a double slip joint it will crack.. No matter what alloy or welds.
2. Turbos are heavy.. The weight of the turbo combined with the vibration breaks welds.


Yes it is'nt a DSM only thing.. Plenty of LS1 firbird turbo kits with tubular manifolds breaking. Guys using ported 6.0 liter truck manifolds are doing fine..

 

[rpmvulocity]

hmm...really metal contracts and expand. i didn't know that. seriously though...that's not what I'm getting at. I'm just simply asking what's the theory behind the tubular manifold. there must be a pro to it cause if there wasn't why would so many pro tuners in the world uses it. i just wanna know what's the story behind it.

 

[MNGSX]

Make the 90 angle to the collector more gradually...

Some minor gains with primarly length tuning..

Use a longer collector...

ETC.. For the trouble it takes to make one fool proof and the fact that you can go fast as hell w/o I just dont see it..

If I had one it would run this double slip collector.. The tube by itself is what gets welded on the primaries to go into the collector then the engine block to turbo brace holds the primary slips in place on the collector.

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[Catbox_95]

In simple terms, it creates a smoother path for your exhaust to take, allowing it to exit the head faster. Best case is to have a tubular manifold with equal-length runners. Since each cylinder fires separately from the others, the exhaust from one cylinder will help suck out the exhaust from the next firing cylinder, so on and so on, creating a ideal flow situation. Some improperly tuned tubular manifolds are actually worse than just a cast manifold, because the exhaust from one cylinder meets the collector at the wrong time, creating back pressure for the next cylinder firing.

I'm a fan of tubular headers. I have one and have had no problems. How much horsepower a car has is solely related to how fast you can get fuel and air in, and how fast you can get it out. The tubular headers helps get it out quicker.

 

[MNGSX]

Eventually I might have one..

However..


1. Standalone EMS
2. Wideband
3. Cams
4. Intake

zero is turbo, fuel system, exhuast etc .....


etc alot of other more important things... I port matched and polished the inside of my 2g.. BR runs 8's on it.. More than good enough for now..

 

[rpmvulocity]

okay..thanks that helps a little

 

[PSIcho]

One thing I want to add that I haven't seen any mentioned in other threads I've read is that part throttle response on street driving is great. Meaning, along with my tubular O2 housing daily driving feels much better even with a big turbo like my 50 trim at say 25% throttle off boost. And at WOT, the boost on starts to build quick like 3-5Lbs. at around 2800RPM. Now, If I can just get a wideband and/or dyno time so I can start tuning this thing.

 

[its3much]

Tubs create WAY more heat then a standard manifold. Theres a study done somewhere on the net, they took an evo vs a tub and the there was like a 40 degree difference

 

[PSIcho]

Tubs create WAY more heat then a standard manifold. Theres a study done somewhere on the net, they took an evo vs a tub and the there was like a 40 degree difference

Underhood temp does appear to be higher. Also, you'll need to replace the plastic handled 2G dipstick otherwise it'll melt it like butter like mine did.

 

[WatchItExplode]

Yes, cast manifolds hold in heat better which is not only good for underhood temps, but power. Minimizing heat loss through the manifold means getting more heat to the turbine which in turn makes it spool better. Sometimes people heat warp tubular manifolds to achieve less heat loss, but it often causes them to crack because of the thin material used on tubular manifolds.

So yeah, mark another point for cast manifolds.

 

[Catbox_95]

True, they do create lots more underhood temps. I use header wrap on mine, and it dramatically reduced underhood temps. I highly recommend using header wrap. As far as them being weak and cracking apart, I suggest you just do like me and cross your fingers and hope for the best.