Exhaust Manifolds

[TheArtist]

To my knowledge, the factory 2g manifold is a good manifold. But my friend tells me a racing tubular manifold is better. Ive read that people dislike them due to cracking all the time. Comments on which is better?

 

[flinguist]

I've heard of cracking problems w/ tubular manifolds, and they're also expensive. The 2G mani. is fine, but there are also some cast manifolds that will flow better than a 2G, and are much cheaper than tubular. Slowboy makes a nice cast one (top of page) http://www.slowboyracing.com/shop.php?sid=&cat=588

 

[Spooling99]

Yes tubular manifolds might be more prone to cracking, but the flow is much better. If your looking at a tubular manifold this is where you dont want to be cheap. There are many nice cast mani's including the one that Flinguist said, some examples being, Evo 3, SBR cast (old and new) and 2g's also SBR makes a aftermarket cast 2g manifold as well, and theres a GT manifold made by turbochargers.com.
-Adam

 

[mjarrell20]

The saying "You get what you pay for." applies here. Tubular manifolds flow much better but cast ones are less susceptible to cracking.

 

[kenamond]

What are your power goals? There are a lot of folks putting down great numbers with ported 2g manis. If you aren't looking for rediculous power and don't have a pile of cash laying around, I think a cast mani will do a great job. Actually, if you are looking for rediculous power and don't have a pile of cash laying around, you're in trouble .

 

[JayRolla]

To my opinion you only want a tubular if your going to build a race car. A ported 2g can flow as much as you need for 500whp. A lot of drag racers go over the mani and reweld all the welds to make it last longer. But they will still start to crack. I have the old SBR cast mani and it had a lot of room for porting.

On a side note kenamond you where telling me on here it is bad to port out the flap inside the mani. When I looked at a non ported SBR mani that flap is already ported in the cast. Just saying it really cant be that bad if they built the mani without that flap.

 

[kenamond]

To my opinion you only want a tubular if your going to build a race car. A ported 2g can flow as much as you need for 500whp. A lot of drag racers go over the mani and reweld all the welds to make it last longer. But they will still start to crack. I have the old SBR cast mani and it had a lot of room for porting.

On a side note kenamond you where telling me on here it is bad to port out the flap inside the mani. When I looked at a non ported SBR mani that flap is already ported in the cast. Just saying it really cant be that bad if they built the mani without that flap.

That's debatable. Go read the www.turbobygarret.com site in its Turbo Tech 102. They describe why you want to separate the 1+4 from the 2+3 and want to make sure 1 and 4 don't blow into each other or 2 and 3 (not as big of a deal). Or read Corky Bell's Maximum Boost which says the same thing.

I have no clue how much of a difference it makes, but it has a purpose.