15 replies to this topic

[martinf]

Hi all,

Need some advice (again).

 

Apparently, there are 2 types of '2.4' manifolds for the 2.2 NA. The more common one, as used by Marc Verboom's write up on the web is part number 12587878. The other one is part number 12602735, which I think may be from a GM Cobalt.

 

Does anyone have any knowledge/experience of the 12602735 manifold? The most crucial question is does it provide similar power/torque gains to the more common (and expensive) 12587878 manifold?

 

I'd be really greatful for anyone's feedback. Thanks a lot.

 

[2-20]

I've never seen any dyno to prove but apparently the new manifold ( also used on post 2007 2.2) would be less effective to move the torque curve in the upper rpm range...
Is it bad or not ? May it depends of the others mods foreseen and what you want to achieve.

[martinf]

Thanks for the reply, I'm not quite sure I understand, are you saying that the 12602735 manifold leaves the torque at a lower Rpm than the other manifold?

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Edited by martinf, 08 December 2020 - 05:34 PM.

[2-20]

Yes,
The 2.4 manifold 12587878 effect is to move your torque curve. You peak torque arrives later and the torque remains higher after peak.( decrease less quickly in the higher rpm).
There's no torque gains.
This translates into more power at high rpm.
I've read somewhere that with the last manifold 12602735 the torque curve is not affected in the same way.But there is no dyno available to show the pattern of the torque curve...

[martinf]

Thanks for the clarification,

Understood. much appreciated.

[oakmere]

Between 3-5k rpm the 08 manifold produces more power and torque at about 5600 rpm the 06 manifold comes into its own.
The OEM manifold which I port matched was a little better on torque than both of the above but only between 3-4K then absolutely dies above 5000 rpm.

[martinf]

Hi,

I thought that the manifold I bought (12602735) was a "06-07" manifold (whatever that means). I also understood that it would increase the bhp by around 15 bhp, is that correct then?

[oakmere]

Yes you have the 06-07 manifold which is the same as the majority converted on here. It provides the most power of all the manifold options and I have tried them all.

[oakmere]

06-07 relates to the date of manufacture. This manifold is now getting difficult to get hold of which is why more are using the later manifold used from 2008. This was used on the 2.2 and 2.4 engines and provide better mid range at the expense of the top end.

[martinf]

Ummh - What is the difference between this and the 12587878 manifold that Mark Verboom (and many others) used ?

[oakmere]

The manifold you have is the same as Mark verboom. There is only 2 types of manifold.

[oakmere]

This thread has the 06-07 and 08 next to each other:
https://www.cobaltss...anifold-286689/

[martinf]

Thanks for the link Martin. I can see there's a clear difference between the two. I can also see that the manifold on the left has larger runners and looks like mine. I don't know why there are 2 manifolds that look identical but have different part numbers, but if they perform the same the that's the important thing.

Thanks for clearing this up.

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[oakmere]

Yes the 08 mani is significantly different.
Not sure about the part No’s as the manifold was from Courtney Sports in a group buy. I assume there was a revision at some point by the manufacture.

[martinf]

Just taxed the VX and took it for it's first run out after fitting a LE5/2.4 manifold, EGR removal, new panel air filter, Pre-cat removal and 'Pipo' mod to the back exhaust box. (plus a whole host of other work like cam/balance chains., etc)

 

Brilliant! - It just keeps pulling all the way to the limiter now. Unlike before when I could definitely feel it holding back around 5k plus. Also, the exhaust note is just right. A little throatier and sounds very nice too. I'm really pleased as it was quite a lot of work. Also, no EML issues  either, although I did take it easy for around 30miles or so.

 

I also fitted some Michelin Pilot Sport 4's all round, 195/45R17 on the front standard rims.

 

I really recommend this mod for anyone who wants to keep it as a 'stock' NA. Looking forward to the next run out.

 

 

[oakmere]

Glad you like it 👍