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sphinx
Sup guys. The basic question is, what are the pros of getting rid of my stock exhaust manifold and replacing it with a stainless steel tubular manifold.

Opinions from all are welcome.
jgreening
For high power applications, you can increase flow and therefore hp with a well designed exhaust manifold. Of course, they look better. The down side is that they are prone to cracking at the welds and, from everything I read, you really don't need it until you exceed 400whp.
presure2
QUOTE
For high power applications, you can increase flow and therefore hp with a well designed exhaust manifold. Of course, they look better. The down side is that they are prone to cracking at the welds and, from everything I read, you really don't need it until you exceed 400whp.

perfect explanation. smile.gif
shid
Jay put everything I've heard about em right on the nose. I know DMC is looking to offload one?
thedevilmaycrie
lol

-DMC
celica3sgte
Not only does it increase airlflow, but airflow decreases backpressure created by a more restrictive manifold. Smaller, more restrictive manifolds(stock) create backpressure on the turbine wheel of the turbo causing decreased boost pressure by not allowing the wheel to spin as fast. A bigger turbo and manifold would be a significant upgrade. Not needing a manifold until 400hp is incorrect. If you have any manifold that is restricting, you are losing hp. And they are not prone to cracking. They CAN crack if it's a piece of garbage. For instance, some of the civic manifolds tend to crack that are made by generic manufactures.
presure2
QUOTE
Not only does it increase airlflow, but airflow decreases backpressure created by a more restrictive manifold. Smaller, more restrictive manifolds(stock) create backpressure on the turbine wheel of the turbo causing decreased boost pressure by not allowing the wheel to spin as fast. A bigger turbo and manifold would be a significant upgrade. Not needing a manifold until 400hp is incorrect. If you have any manifold that is restricting, you are losing hp. And they are not prone to cracking. They CAN crack if it's a piece of garbage. For instance, some of the civic manifolds tend to crack that are made by generic manufactures.

most of what ur sayin here is true...but on the 3s, its dyno proven that under 400whp, a aftermarket exhaust manifold isnt gonna give you a signifigant gain in HP. smile.gif
sphinx
I love this place. biggrin.gif
celica3sgte
The type of motor has nothing to do with it. Actually, all of what I said is true. If your manifold is restrictive, you are limited.. IT CREATES BACKPRESSURE,,on the turbine wheel, at a certain point of boost. Upgrading the manifold=boost more:} So are you telling me that I should run my 15 psi of tuned boost from a 60 trim t3/t4 on the stock manifold. lol. cmon dude. If you have ever tried running boost on a restrictive exhaust component, it's ridiculous you just don't go anywhere.
So sphinx, I think I saw that you have an upgraded turbo. A manifold is only about $500-$600. If you plan on running some good boost, get some injectors, a fuel rail, and make sure your exhaust is open from top to bottom.
shid
celica3s, what you're saying in theory is true, but what pressure is saying in pratice is true. It might be that the 3s stock manifold is better made than most stock manifolds, or it might be the CT26 turbo itself.

Whatever the reason is, it still remains that for the 3sgte motor, an aftermarket manifold doesn't do much until 400 hp or above.
celica3sgte
That's a retarded comment. lol. There is no theory here. It's called physics. Neither of the two of you who are arguing with me even have a turbo on your car. Have you even felt what I'm talking about???? Have you been in a turbo charged car with a small exhaust, and soon after upgraded the exhaust. It's night and day. Any small exhaust component will limit your airflow. Hey shid once you get done with your swap and drive the car, you'll know what i'm talking about. It will feel completely different with an exhaust on compared to an open downpipe. You aren't going to gain 80 hp here by upgrading a manifold. However, any exhaust upgrade you do is quite significant in bolt on terms. 10 whp is significant. BIgger downpipe 10hp, 3" exhaust 15 hp, manifold more hp, no cat more hp.
shid
no celica, you're talking about physics, and that is theory. Remember until you get to higher level physics, you're always assuming spherical objects?

What we're saying is that the exhaust manifold on the 3sgte is supposed to be pretty damn good, it's not supposed to cause much backflow, and thats why upgrading it right away at stock levels isn't a good option.

I haven't seen the dyno results pressure speaks of, but its what I've read on mr2oc etc.
jgreening
Actually, Steve is right about Exhaust Manifolds. A properly designed manifold will flow better than the stock exhaust manifold - particularly in the midrange RPM's. However, the stock manifold WILL support 400whp. That is dyno proven. So, in a way, you're both right.

I am very appreciative of the guys on this site that have extensive mechanical experience to share with people like me that are just getting into it. Lets not take their opinions lightly simply because we have READ something different elsewhere. Without guys like Steve, Lagos, Kwanza and others, where would this community be?
ToYCeLi8
Thanks for asking this Sphinx i was thinking the same thing. But to save some money instead of getting the tubular mani, I was wondering how a 3sge mani would bolt up to a 2nd gen 3SGTE? Or would it bolt up better to a 3rd gen? here is the pic
user posted image

Its about $600 about half of the tubular mani? BUT again if the stock 3sgte does hold up 400whp then why bother? I dont really think i wanna go too much over 300whp. Anyway, any opinions or information is greatly appreciated.

Soon to be Boosting,
David
Insanity-74
When you are thinking about putting an aftermarket exhaust manifold on a turbo car, you have to be alot more careful than a N/A car, back pressure shouldnt be your only concern at all when fitting the manifold, its all about exhaust gas velocity used to spin the turbo. This is where things start to get a bit more complex, you have to find the fine line between having a wide exhaust manifold to get rid of the exhaust gases qickly and less exhaust gas velocity and having a thin exhaust manifold high exhaust gas velocity but possibly not allowing all the exhaust gases out quick enough. From pure trial and error and bitter experience you need to be looking at a 2.75inch manifold, 2.5 inch works OK if your planning on keeping a standard turbo with few/no mods. 3 inches reduces the exhaust gas velocity to a point where it dosnt spool the turbo up quick enough (unless you gonna have a BFO turbo).
shid
Uhh, Toy? You can't put an exhaust manifold from an NA car onto a turbo'd car.
sphinx
QUOTE(shid @ Mar 6, 2005 - 1:55 AM)
Uhh, Toy? You can't put an exhaust manifold from an NA car onto a turbo'd car.
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that's what i was gonna say.
lagos
ToYCeLi8 ....the only way you could fit that was if you got rid of the turbo on the 3sgte....not something i would consider an "upgrade" .lol.
ToYCeLi8
QUOTE(lagos @ Mar 6, 2005 - 11:21 AM)
ToYCeLi8 ....the only way you could fit that was if you got rid of the turbo on the 3sgte....not something i would consider an "upgrade" .lol.
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NO i was going use it to make a hybrid manifold. But if there is no need for it then its cool. Ill just clean mine up to look better for presentation.

Thanks tho guys, biggrin.gif

Soon to be BOOSTING,
David
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