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Discussion Starter #1
I've looked about on this and not getting too much info on it. If I do find info it's always a debate. So it's 2017, resonator, in or out?
 

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If you mean the intake resonator it's there to improve the flow of air to the engine. Very carefully designed to give a broad level of power and torque. Why would you want to have less power and torque?
 

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This was the debate that I seen, people saying that it does and doesn't do such things. I'm not an expert or at anyway educated in that area so curious as to what is the truth. People I seen had removed it, they said it gave them a deeper note to the engine and didn't notice any difference, others were saying what you said about so I got confused easily lol
 

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Normally they are there to reduce intake noise, removed them on cars before withn no ill affect on performance, watching this thread with interest
 

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How the air flows through the inlet is critical to the performance of the engine. Engineers don't remove it and think they can't tell the difference. They will measure the difference.
You've noted that it's louder when you take it off and you've proved the performance loss. Noise is energy; and what you are hearing is energy being wasted.

This is a very simplified response. The actual 'tuning' of the inlet tract has many facets. If you want power between 5000 and 6500 RPM you would have a short inlet tract. This short inlet tract would ruin Torque and you would find it very difficult to accelerate from standstill. The engine would 'bog down'. Some cars have been designed with variable length tracts to switch over as engine speed increased. What we now find is that a carefully designed resonator will cover virtually all engine speeds.

Of course you could still go down to your local accessory shop and buy a totally untested filter and trumpet and be gullible enough to think you have purchased and improvement. Whatever it says on the box these companies can't afford to acquire every car on the market and test the outputs with their device attached. If they did you would be paying thousands for the product.
 

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Of course you could still go down to your local accessory shop and buy a totally untested filter and trumpet and be gullible enough to think you have purchased and improvement.
Surely this would only be the case if you were discussing a Vauxhall Corsa 1.0? Dont think I could take a hacksaw to my 159, even the intake pipes look good!
 

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Fancy intake pipework is only really needed on none turbo cars.

Pre-Turbo you just want as little restriction as possible. None being the best case scenario for air flow rate. Post turbo the smoothest most unrestricted pipes possible with the least diameter changes possible.

However having done some research into these cars anyway the whole car is programmed to aim at certain air flows, boost pressures etc anyway. So removing pipework without a remap (Specially if the MAF isn't re-calibrated for the new air flow paths) will not make much difference at all.

I'd just leave the resonator in place. It's not doing any harm to flow just reducing noise and whistle sounds.
 

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Fancy intake pipework is only really needed on none turbo cars.

Pre-Turbo you just want as little restriction as possible.
Wrong. This is 1980s thinking. If you run straight pipes (and that doesn't mean it has little restriction) you will be tuning the engine for one power band at top revs. Even race cars don't run at one rev range. You need torque as well. The very best performance comes from a slowly building power curve with a flat broad torque curve. If you look at the modern tuning applied to 60s saloon racers you will see a long inlet tract.
 

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Wrong. This is 1980s thinking. If you run straight pipes (and that doesn't mean it has little restriction) you will be tuning the engine for one power band at top revs. Even race cars don't run at one rev range. You need torque as well. The very best performance comes from a slowly building power curve with a flat broad torque curve. If you look at the modern tuning applied to 60s saloon racers you will see a long inlet tract.
Yeah but none of those N/A cars have a huge turbo on them? Tuning and length and resonance matters a lot in N/A none turbo cars but on a fat diesel with a turbo on it's not that important what's in front of the turbo so long as it isn't restrictive. After the turbo and the intake manifold design is important still however.
 

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This was the debate that I seen, people saying that it does and doesn't do such things. I'm not an expert or at anyway educated in that area so curious as to what is the truth. People I seen had removed it, they said it gave them a deeper note to the engine and didn't notice any difference, others were saying what you said about so I got confused easily lol
"If you can't do the Math, then don't question the Formula"
 

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Wrong. This is 1980s thinking. If you run straight pipes (and that doesn't mean it has little restriction) you will be tuning the engine for one power band at top revs. Even race cars don't run at one rev range. You need torque as well. The very best performance comes from a slowly building power curve with a flat broad torque curve. If you look at the modern tuning applied to 60s saloon racers you will see a long inlet tract.
What, you mean flat like this? Stuff - it, I'm going to take off the inlet manifold, bin the cats and put a nice shiny stainless exhaust on her. Huh! What do Alfa know about tuning engines?
 

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Discussion Starter #14
Still looks like a debate to this day from finding topics about it years ago. I've only had my 159 for a few months, so before I do anything to it which is gonna be very little I'm just educating myself on the do's and don'ts, the resonator was just something I couldn't find a definitive answer to.

Got good replies on the topic though, thanks for the efforts and replies guys.
 

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Still looks like a debate to this day from finding topics about it years ago. I've only had my 159 for a few months, so before I do anything to it which is gonna be very little I'm just educating myself on the do's and don'ts, the resonator was just something I couldn't find a definitive answer to.

Got good replies on the topic though, thanks for the efforts and replies guys.
just get the egr done, DPF work is now illegal, and leave everything else as designed :) - get a remap if you want more poke
 
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Still looks like a debate to this day from finding topics about it years ago. I've only had my 159 for a few months, so before I do anything to it which is gonna be very little I'm just educating myself on the do's and don'ts, the resonator was just something I couldn't find a definitive answer to.

Got good replies on the topic though, thanks for the efforts and replies guys.

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Join Date: Mar 2003
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Perfect

Good, and just to ensure the penny has dropped with respect to the observation "Old Engineer" is making.

"If torque were constant across the rev range of an engine, then power developed at a given RPM is

:- Power "x" = Torque X RPM/5252. Therefore assuming from the Dynamometer plot, the torque at 6670 RPM is 210 (lbft) On the assumption it held up to 7200 RPM - Alfa's limit - it would extrapolate to

:- 210 X 7200/5252 = 287.89 bhp. Strange, that is exactly where I predicted it should be!!!

If however, the torque was to hold up to 7500 rpm, the power would be :- 210 X 7500/5252 = 299.88 bhp.

This is a very good engine indeed.:surprised: I think not!

PS. the overlaid plot is supposedly the Alfa one - if you want to believe it!
 

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