Extractor Manufacturing

[Tradewind]

Ah, I didn't know that story - bit of googling and I understand

Seems old mate is a bit protective hey.

Well one thing for sure we can confirm that apart from K2 there is no existing extractor products for the Liberty/Legacy 6cyl vehicles

[kiks]

If you do the sums in engine analyser, at high lift and a 6700rpm peak power, the primaries need to be 4.8feet long from memory. Al from AM also went this route with a total guru in engine flow and found for that gen 2 ez30 converted thing, the primaries would need to be back to behind the rear diff for the peak power rpm he wanted.

The factory manifolds are fairly much perfect for low rpm torque.

Whats the goal of new manifolds? Aside from an awesome noise? (which is so very very worth it! h6 on cam with open pipes is adultery with my ears)

[kiks]

Scratch that...sets made with a proper scavenging equal length primary would be a goer, only limit is ground clearance really. Forget peak flow rpms etc. Anything would make an awesome noise and pick up a few ponies

The factory h6 has a big insulated heat shield thats needed too, so whatever you make, make sure it has at least some decent heat shielding. It gets bloody hot down there and the heat soak in the upper area of the sump is huge as it has no water galleries.

[Tradewind]

Kiks

Thanks for tip on heat shield, last thing we need is HOTTER oil

[bates91]

ahhh powerchip besanko saga, too hilarious

i could be interested in some extractors...depending on how it sounds and any performance gains to be expected

[BJ]

Can you give some more information please? Will the primary pipes be equal length? What will that length be? Will they connect to the existing Cats?

[Tradewind]

Will connect to existing cats, flanges provided

Pipe length will be as you find in the K2 Product

[BJ]

If you do the sums in engine analyser, at high lift and a 6700rpm peak power, the primaries need to be 4.8feet long from memory.

I don't think you've got this quite right. The idea of extractors is like this:
When the exhaust valve opens, a pressure wave travels down the pipe at the speed of sound. When the wave reaches the end of the primary pipe at the collector, it continues on, but part of the wave is reflected back towards the engine. If the exhaust valve is closed when the wave gets there, it gets reflected back down the pipe again, leaving a low pressure area behind. If the exhaust valve now opens, the exhaust meets a low pressure area behind the wave and so you get the "extractor" effect of the exhaust being assisted by the wave from the previous event. The timing of this depends on the length of the primary pipe and the engine speed.

Obviously, this only works for a narrow rpm range. The length of time it takes the wave to travel down the primary pipe and then back again is matched to a particular engine speed. This is why they are "tuned length" and why you get that musical note with an open exhaust system, it's like organ pipe theory. It is usually timed to coincide with peak torque, or just after, somewhere between peak torque and peak power.

I don't have the information available to me now, but the length of the primaries to correspond to about 5000 rpm, which is what we would be looking for, is about 750 to 800 mm. Primaries 4.8 ft long would be for around 2500 rpm, which is no good. Looking at the K2 item, it seems that it would be tuned to about 9000rpm, which is a waste of time. They might improve the performance a bit but you will not get that "extractor" effect that you are paying for.

[kiks]

Justs you know, I just did this again as a 1.45L 3cyl assuming a 100% VE so knocked a bit of capacity off. I cant work out a VE easily at home sorry.

250/246deg cams on high lift of 9.75mm and 10.0 on the intake. I dont know the phasing heights sorry.

42" and a secondary collector at 154" for a 6200rpm peak power.
Reducing this to 34" and a 60-70" seconday collector (almost irrelevent) for 6600rpm.

The original figure was for a straight 6 with slightly larger cams, my bad.

The above longer pipes would work best collecting straight into a straight through resonator. No cats as theyre shit...

What makes our engines shit for this is that the lengths can not be equal either, as the exhaust ports are not equal length. I can supply you some measurements if you need, I have a few EZ30's sitting downstairs.

So as it stands, loooong mofokin pipes, and smooth merge collectors are the go and as free a cat as possible, into a collector and then a resonator, and a length of pipe to mate up to the 1:2 split at the rear.

Dual pipes all the way to the back would be fun too though Certainly sound f*cking unreal, 15000rpm of 3cyl with non crossover twin pipes would be the ducks guts for noise.

For what its worth, this is what has been done prior:


Thats the input of this man on design:
http://www.billzilla.org/
And the fabrication of these guys:
http://amauto.com.au/home.html
To give fair credit to the picture above.

People should remember that the Ez30r is not like a big meaty NA engine, it has relatively subdued cams and big slow exhaust ports etc.

[kiks]

Can you give some more information please? Will the primary pipes be equal length? What will that length be? Will they connect to the existing Cats?

Just incase you missed it, the exhaust ports are not equal length brother.
The existing cats are utter garbage and are costing you 25hp just from being there.

[Tradewind]

The existing cats are utter garbage and are costing you 25hp just from being there.

Even in NA form? If thats the case then the people with superchargers installed better get theirs changed out ASAP, if its 25hp loss NA it will be 40+hp loss with boost, thats how it is with a Holden V6.

[BJ]

It sounds like I'd better replace the cats then, thanks for the advice.

[Tradewind]

It would be useless for me to make headers connect to rubbish cats

Will be headers and cats together now

[MH3.0R]

Tim,

Any progress on this topic? Have you made up a set for yourself?

[Tradewind]

Hi

I hadnt noticed that the vote count is now 3:1 in favour and that we have 15 votes

I think we can make some progress on this matter now, until this very moment I hadnt entertained the though further. Given the results of the tuning on IWISH's SC car verses everyone else I think there is significant power gains in the extractor/front cat area

Back on the agenda, but give me a bit of time. Hoping to complete the intercooling in a couple of weeks at the most - first