Performance manifolds

eidolon

eidolon

eidolon

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With all this sports cat talk I got looking at the whole induction/exhaust thing and thought that I might as well go the whole hog and get a manifold and decat.
Apparently the standard manifold is too short and compact to tune well and was primarily designed to get the cat the light off quickly and pass EU4 emmisions.

What sort of benefits can be gained from a decent manifold? Does it shift the power delivery up/down the rev range? (I don't want loads of top end power at the expense of losing drivability)
 
A tuned-length manifold should increase torque across the rev range and power a bit at the top end.

*n
 
As penski said there - the really decent manifolds are put together by proper engineers who have properly researched exactly how long each of the manifold branches should be and also found a way of constructing the entire product with the least amount of bends as possible.

Getting the branch length bang on ensures that as each cyclinder exits exhaust gasses - that "slug" of exhaust gas doesn't immediately collide with another slug off other cylinders.

Mine was serious money, but (imo) worth it. It's ultra light and gets results.
 
Check out this bad boy -

k20hdr3.jpg


:cool:
 
what car is it to go on? if the stock is restrictive then even a cheaper SS will yield significant results. i imported a stainless steel header from the US, (cost me £131 all in), and it is reportedly good for 8-10bhp depending on mods etc!

u can deffo feel a difference with it on!
 
I thought the best desgns used equal length pipes and is developed in such a way that pulses from each cylinder can't affect the other.
 
Bike throttle bodies on a Bogg Brothers' manifold and a good exhaust fannymould would be awesome...

*n
 
penski said:
A tuned-length manifold should increase torque across the rev range and power a bit at the top end.

*n
Click to expand...

Depends on the design though, a 4:1 is only "tuned" across a narrow RPM range, and is usualy designed to boost torque near peak power. They can also cause holes in the torque at lower RPM where the tuning works against the engine.

A 4:2:1 gives a wider spread of torque though generaly at the expense of less peak power.
 
I had a 4-2-1 equal length manifold on my VTR, performance difference was quite remarkably, it seems a lot more willing to rev, and did it a lot quicker, also weighing a lot less helps a lot aswell (if your into that).

I took a cheapskate route and paid £150 for one off eBay, never did me wrong inthe 3months it was on.

My friends just purchased one through eBay aswell for his Impreza.
 
could ideally do with matchign it to the head. if there is a lip between the head and the manifold doesnt have as much "power" impact.

but same as any mods. better done in conjunction (nice word) with other mods.
 
Sounds like it's definitely a good thing then, now just got to find where I can get one.

It looks like there's only Janspeed who sell them and the guys on SELOC seem to reckon they're prone to cracking :(
 
Not sure what these cars are like but over on Cliosport a popular mod that frees up quite a bit of poke is to get the inlet manifold matched. Apparently the castings for the 172/182 inlets weren't great and there's a distinct overlap with the gasket.

Using the gasket as a template people polish/grind it down so that the holes match nicely :) Or they pay around 170 for someone to do it for them :)
 
The only reason why a 182 is not a 172 is because it has a different manifold. A 4-2-1 as opposed to a 4-1 (I think thats what is on the 172). You can source a 182 manifold for about £200. Shame it costs a lot in labour to fit it.
 
eidolon said:
Sounds like it's definitely a good thing then, now just got to find where I can get one.

It looks like there's only Janspeed who sell them and the guys on SELOC seem to reckon they're prone to cracking :(
Click to expand...
Do EBD not make a 4-2-1 for the newer cars?
 
Nickg said:
how much to fit on a 172? i paid a garage ~ 70 squid to fit with new downpipe also
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About £200 iirc :(

Plus you need to butcher the cat somehow to get it all to fit. Either get a 182 cat, chop and weld a 172 cat up, or make up a decat pipe.
 
Ev0 said:
About £200 iirc :(

Plus you need to butcher the cat somehow to get it all to fit. Either get a 182 cat, chop and weld a 172 cat up, or make up a decat pipe.
Click to expand...

Ktec sell a 182 manifold mated to one of their sports cats, but iirc its in the region of £600 :eek:
 
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