Which manifold???

Hi everyone,

Im planning to go single turbo soon.Ive bought a PHR stage 1 turbo but i dont know which manifold to go for either Cast short-runner or s/s tubular manifold?? Im only planning to go max 550bhp. and i want super fast spool. Which manifold do you think will be best for me?? or what are the pros and cons of each manifold??

Thankx

i think it would be the short manifold for the phr for the fast spool. not much in it only the price i think.

I'm going for cast.

Benefits are:

Cost

Spool

More torque

Drawbacks are:

Slightly less BHP

Restrictive after silly HP

Not as shiney and nice

Did I see you coming out of strathclyde park last week? Onto the raith roundabout?

ask lui about it he has a street phr kit

I'm going for cast.

 

Benefits are:

 

Spool

More torque

I hear people say it but any proof behind that statment?

Ive sold the supra its away london.Ive got a Mk2 Aristo with the vvti 2jzgte. I needed more space.

I just go with what I'm told

Cast is much much shorter though, that would justify the faster spool. That would lead to more torque down the rev range IMO.

I don't know if by the "more torque" quotes they mean peak or low revs. Going by when most people hit max torque they might be one and the same though.

I have the cast mani, well same kit as Lui actually...

How do you find it??

I have the cast mani, well same kit as Lui actually...

Whats your power and torque and what boost? any dyno graph?

I hear people say it but any proof behind that statment?

Wez's engine is a good example of the spool gains when using a cast manifold, especially when it was running small cams. The "more torque" quote is a little misleading, the early spool is what gives the higher low/mid range torque when compared to tubular, not the manifold itself as such. I've written a fair bit about manifold choice but haven't got time to finish the article yet

To the OP - are you using an auto or manual gearbox? Are you likely to want more than 550bhp at any point in the future?

Im using a auto. 550-600bhp no more.

You're going to be limited to ~550bhp at the flywheel unless you change the box.

BTW, here's a copy of of what I'd had noted for the manifold part of the single turbo FAQ. It's completely unfinished but should cover some of the basics.

Choosing the manifold type

 

This is often overlooked. There are two options available – cast and tubular. The tubular option is by far the most commonly used due to their availability; however that is not to say it is always the best choice. It’s important to note that the position of the turbo in the engine bay is different between the two types which can cause some off-the-shelf produce to not fit correctly, see below.

 

Cast

 

The manifold itself is very similar in look to the stock TT one, with just some small changes to the flange to allow an external wastegate and single turbo fitment. Both have their advantages and disadvantages:

 

Advantages:

- Cast is considered the most reliable and strongest compared to tubular

- Much cheaper to purchase

 

Disadvantages:

- It is limited in terms of the power it can produce due to flow limitations of it’s design, they generally have a 550-600bhp power limit.

- Availability of bolt-on manifolds is scarce, many require modification to be workable.

- Different position of the turbo means that a specialised downpipe, screamer pipe and intake is required

- They don’t sound all that great compared to tubular

 

Tubular

 

This manifold design is by far the commonly used due to them being the choice for most kit suppliers.

 

Advantages:

- Higher flow tubular design means that they are not limited to the 550-600bhp range of a cast manifold. The commonly used T4 manifolds from the likes of BL, HKS, Greddy, etc are proven to work up to 900bhp.

- Huge availability and choice

- Sound nicer than a cast manifold

- Downpipes, intakes, etc are available off the shelf to fit this type of turbo position

Disadvantages

- More expensive to purchase, though this can be offset due to single turbo package price discounts

- More prone to cracking than cast

Wez's engine is a good example of the spool gains when using a cast manifold, especially when it was running small cams. The "more torque" quote is a little misleading, the early spool is what gives the higher low/mid range torque when compared to tubular, not the manifold itself. I've written a fair bit about manifold choice but haven't got time to finish the article yet

 

To the OP - are you using an auto or manual gearbox? Are you likely to want more than 550bhp at any point in the future?

Wez is on a lot smaller turbo than me and it only just spools a tad faster, 50rpm id guess, i think Dandan is on cast, his spools pretty well but if i remember right he is on stock cams.

Im not convinced.

Wez is on a lot smaller turbo than me and it only just spools a tad faster, 50rpm id guess, i think Dandan is on cast, his spools pretty well but if i remember right he is on stock cams.

 

Im not convinced.

I know where you're coming from but I'm referring to Wez's old (more basic) setup.

Your engine is so far modified it makes it difficult to become a base comparision for a generic setup IYSWIM.

Wez is on a lot smaller turbo than me and it only just spools a tad faster, 50rpm id guess, i think Dandan is on cast, his spools pretty well but if i remember right he is on stock cams.

 

Im not convinced.

Is that not comparing apples with oranges though J? Did you not say that your tubby is a bit of a hybrid given how fast it spools?

You would need to take your tubular off and put on a cast to see the comparison.

Darryl, are the folks selling the cast manifolds quoting 900hp just plain lying or are they a different design from previous cast manifolds?

I know where you're coming from but I'm referring to Wez's old (more basic) setup.

 

Your engine is so far modified it makes it difficult to become a base comparision for a generic setup IYSWIM.

Wez old setup on stock cams? Ryan said that graph was not right, done in the wrong shoot out or something.

I belive with proper cooling and a torque coverter the box should be good for 600bhp flywheel. i might even look into getting it uprated.

Cast mani £350

Tubi Mani £1200

Is it really worth the extra £850??

Its all down to what you are after. Different horses for different courses. Would have thought the previous posts would have covered that by now though

Cast mani £350

Tubi Mani £1200

 

Is it really worth the extra £850??

Just to throw another spanner in:d

http://www.obxracingsports.com/products.php?pk=1032

How long will it last though??

How long will it last though??

You seem to have convinced yourself cast is the way forward so best to go with that bud:)

OBX manfifolds look pretty good, they are a budget one, but are a different world to the likes of XS power. Seen one close up and they appear to be well designed and welded. It did still need a machine on the faces though.

There's not much around the forums how durable they are though.

You seem to have convinced yourself cast is the way forward so best to go with that bud:)

I havnt.Its just that everyone says cheap tubi's crack.