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Author Topic: Vortex Exhaust Sytem  (Read 7473 times)
Anders Dinsen
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« Reply #15 on: July 14, 2010, 11:35:18 pm »

When we are speaking about engine tuning... is there somebody who has more than 150PS from 2,2 engine?

I plan to get there with my ported cylinder head etc.

You can compare it with resonance.

It *is* a resonance effect. It's like an organ pipe or flute only wanting to play one note - at that note, the air flows through more easily than at others, where the waves die out and energy is lost.

It pays to consider this resonance effect because it's there and it makes a considerable difference whether you want it or not. And if you think of it, a muffler far down in the exhaust system is probably not "felt" by the engine as even if it restricts the exhaust a little, it also opens up the exhaust and allows the pressure waves to die out instead of coming out of the exhaust outlet. That applies to the inlet as well. So a well designed and damped muffler can be seen as an open outlet from the engine.

So exhaust resonance tuning is a good tool to increase and/or moves the max torque point of the engine to the most RPM.

The other effect is that of the vacuum on the back of the exhaust bubble. To benefit from that you need vacuum, which you won't have in a completely open or restrictionless exhaust system. So there's a point where there will be too little restriction! Now, the vacuum on the back of the exhaust bubble is distributed back to the other cylinders from the place where the runners are joined, where the (low pressure) wave will travel (at the speed of sound) back. Depending on the exhaust design and engine RPM, it will either aid the scavenging of the cylinder (as in a short manifold where cylinders are joined by pair, as in the Murena 2.2 cast-iron manifold), or starting the early suction of air/fuel mixture into the cylinder during the cam overlap when both inlet and exhaust valves are open (as on the 4-in-1 manifold with its longer runners). Or both!

All that said, I don't think there's a design rationale behind the 4-in-1 manifold on Murena - and I don't think anyone will have the inclination or money to spend on trying out different designs. Except GP perhaps? Wink However, it looks and performs well!

/Anders
« Last Edit: July 14, 2010, 11:37:42 pm by Anders Dinsen » Logged

'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Jon Weywadt
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« Reply #16 on: July 15, 2010, 12:31:25 am »

One thing I want to try on my 4in1 exhaust, is to wrap it in insulation. I have seen kits with insulation tape and straps.

I am thinking that it could help on the wave and at very least help reduce the heat generated in the engine compartment.

Also, my 4in1 is not stainless and ugly rusted, so it will make it look better. Cheesy
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Matranaut par excellence Cool
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« Reply #17 on: July 15, 2010, 01:48:23 am »

When we are speaking about engine tuning... is there somebody who has more than 150PS from 2,2 engine?

Yes me.

I am hoping next week to book a day at the rolling road to find out out the definitive conclusion to the Vortex exhaust technology mystery??? Will keep you posted.

P.S. To answer Jon's question also, I currently have fitted a 4 x branch stainless steel exhaust manifold wrapped in Thermo-Tec COOL IT exhaust insulation. This does considerably reduce the heat in the engine compartment and I can only presume it assists with the performance output, along with the gas flowed head, 2 x 45 Weber DCOE carburettors and 150Cv Politechnic Camshaft, as the graph attached below seems to confirm.

http://www.thermotec.com/technology/10-how-does-it-work.html

GP
« Last Edit: July 15, 2010, 08:37:12 am by GP » Logged
michaltalbot
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« Reply #18 on: July 15, 2010, 06:00:10 am »

When we are speaking about engine tuning... is there somebody who has more than 150PS from 2,2 engine?

Yes me.


How much?
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Anders Dinsen
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« Reply #19 on: July 15, 2010, 06:57:58 am »

P.S. To answer Jon's question also, I currently have fitted a 4 x branch stainless steel exhaust manifold wrapped in Thermo-Tec COOL IT exhaust insulation. This does considerably reduce the heat in the engine compartment and I can only presume it assists with the performance output, along with the gas flowed head, 2 x 45 Weber DCOE carburettors and 150Cv Politechnic Camshaft, as the graph attached below seems to confirm.

I don't think it helps. It may even do damage since the heat is kept in the exhaust, potentially causing damage to the manifold and - worse - to the cylinder head. The Murena's engine bay cooling is well designed by the airflow around the engine and under the trunk, plus the carbs and inlet is on the "cold" side of the engine, so as long as you have a good supply of fresh air into your carbs, heat radiated from the exhaust will not affect the inlet side at all.

Further, the other argument presented by Thermo-Tec is wrong. To aid scavenging and overlap, you want the exhaust gasses to cool down as they travel down the manifold. Cold air has lower pressure than hot, and it's low pressure you want transmitted back to the exhaust valves in either case.

/Anders
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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
GP
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« Reply #20 on: July 15, 2010, 08:37:51 am »

When we are speaking about engine tuning... is there somebody who has more than 150PS from 2,2 engine?

Yes me.


How much?
158.2 bhp /66321 rpm (160.4 PS)
136.8 lbft / 4804 rpm   (18.9 kgf/m)
« Last Edit: July 15, 2010, 08:52:21 am by GP » Logged
Jon Weywadt
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« Reply #21 on: July 16, 2010, 12:41:14 pm »

Looking at my 4 into 1 exhaust manifold and looking at pictures of the Politeknic stainless version, it looks like, on both, the tubes do not have the same length from the head to the common point.

That concerns me, since I plan to convert to an injection manifold and use a MegaSquirt controll box. I planned on mounting the wide-band Lambda probe at the common point of the exhaust manifold. But if the pipe length is not identical, then it seems like the exhaust pulses could throw off the MegaSquirt. I assume it adjusts timing based on the pulses and oxygen mix at the sensor and if they do not arrive with the same delay, will the MegaSquirt be able to adapt quickly enough? Huh

Do anyone you have experience in such matters?
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Matranaut par excellence Cool
Anders Dinsen
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« Reply #22 on: July 16, 2010, 04:15:30 pm »

Do anyone you have experience in such matters?

It's not a problem. Megasquirt doesn't adjust mixture one cylinder at a time, but all four. Unless something is very wrong with the engine, they will always require the same mixture. It may time the firing of the injectors individually based on the crank sensor, though that should not be necessary.

Why do you think they are not identical length? Looking at Politecnics photo, I think they are roughly equal:

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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Jon Weywadt
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« Reply #23 on: July 16, 2010, 06:06:43 pm »

---
Why do you think they are not identical length? Looking at Politecnics photo, I think they are roughly equal:



Roughly is right,  Wink If we call the rightmost pipe cylinder 1 and the left most cylinder 4, then looking at the pipe to cylinder 1 and comparing it to cylinder 2 they start with the same bend from the junction and then cylinder 2 angles off to the left, thus needing a longer pipe to reach the head. The same goes for 3 and 4. It is hard to tell if there is a difference between 1 and 3 or 2 and 4.

But for a perfectionist like me it just don't look quite right.  Cheesy I think you would agree, that for optimal performance and tuning, all four tubes should be exactly the same length, as they are in serious racing  applications. Grin
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Matranaut par excellence Cool
Jon Weywadt
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« Reply #24 on: July 17, 2010, 02:09:23 pm »

The Vortex might not fit on this Porche.

http://ekstrabladet.dk/biler/bil_nyheder/article1377812.ece

But what a radical engine swap. I would like to put that in my Murena.  Grin

365 BHP + 949NM torque Shocked
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Matranaut par excellence Cool
GP
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« Reply #25 on: August 03, 2010, 10:17:55 am »

The Murena has now been on a rolling road for a power run first with the old exhaust, followed by a power run with the new "Vortex" exhaust.

Old Power: 157.4 BHP / 6640 1/min   ---------    New Power: 161.5 BHP / 6711 1/min
Old Torque: 141.0 lbft / 4044 1/min   ---------    New Torque: 139.0lbft / 5626 1/min

So an increase of 4.1 BHP or +2.6% was achieved with a -1.4% loss of Torque.

See attached power/ exhaust  graphs printout for further information.

Conclusion: It does not achieve what it claims in any way!

The noise is also quite unbelievable. I have just driven the car home 27 miles, I have a splitting headache and cannot hear a thing. I received a phone call  en-route and was asked if I was inside a Spitfire or something similar?  Embarrassed

Tomorrow the “Vortex” exhaust is coming off. Ah well, win some, lose some!  Grin

« Last Edit: August 03, 2010, 01:40:43 pm by GP » Logged
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