17 replies to this topic

[Java_Green]

According to diverce sources the recommendations is to go for an 2" exhaust when power exceed 100bhp. Any recommendations considering manifold as well on 2 box system with side exit? Preferably with the slide on fixations. Any good stainless steel options for the system?

[nicklouse]

Nah, what power exactly?

would not, did not go that big for 124.

 

but application and build will determine what size you need.

[Java_Green]

7-port, supercharged (~9-10psi), fuel injection (port injected), rev limit at 6500rom. Not sure how much power/torque I will get.
What I do not want is things going hotter than needed due to too much back pressure.

[absx2]

7-port, supercharged (~9-10psi), fuel injection (port injected), rev limit at 6500rom. Not sure how much power/torque I will get.
What I do not want is things going hotter than needed due to too much back pressure.

 

I did wonder why a 2" exhaust and now I know :)

 

I don`t think you can go wrong with a Maniflow system, you can talk to them and they can get you what you need.

 

https://www.maniflow...ry&category=201

Edited by absx2, 09 March 2025 - 08:25 AM.

[Steve220]

If you can get hold of one, playmini used to make a 2" stainless system, but stopped producing them a few years ago. They often turn up second hand.

[IronmanG]

Bagsport do exhaust with your choice of size number of boxes etc

[Java_Green]

Are the inlet ports in a 2" manifold (e.g. C-AHT289) larger than standard?

[imack]

Are the inlet ports in a 2" manifold (e.g. C-AHT289) larger than standard?

They are on my Maniflow large bore long
3 into 1 manifold.
Large bore competition gasket perfectly matches the exhaust ports in the head and in the manifold. Gasket shown on standard head for comparison, plus modified head vs standard.

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[nicklouse]

Are the inlet ports in a 2" manifold (e.g. C-AHT289) larger than standard?

Sorry no such thing. The 2” is the exhaust.

 

the manifolds that fit a 2” exhaust can be various diameters but in all cases the center one is larger.

[Java_Green]

Hmm...
If it is just the exit of the manifold that is matching a 2" system, changing the Y-piece should be enough. Am I right?

[timmy850]

It’s clear from the pictures from imack that his manifold is definitely bigger at the ports too. I would assume it’s bigger from the ports all the way to the collector

I think Nick has read that wrong and thought you’d meant 2” from the head

[Java_Green]

Are the inlet ports in a 2" manifold (e.g. C-AHT289) larger than standard?

They are on my Maniflow large bore long
3 into 1 manifold.
Large bore competition gasket perfectly matches the exhaust ports in the head and in the manifold. Gasket shown on standard head for comparison, plus modified head vs standard.

I would very much appreciate if you could measure the exhaust port sizes of what is named as "large bore".

[imack]

Engine is currently fully built and in the car, so not possible to measure. It's the competition gasket from MED. They only list one exhaust port dimension, I don't know whether it's an outer or centre port.

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[imack]

The pictures I posted were taken a few years ago. I'm certain that I actually had to enlarge the exhaust ports on that gasket using a dremel, to match the ports in the head and in the manifold.

[imack]

Double post

Edited by imack, 01 April 2025 - 04:30 PM.