Remove Resonator for Intake Or Change Exhaust?

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I think the others took "Lean Burn" to mean "Honda Civic".

"Ass U Me" is a good description.

The questions relate to the Pulsar, which is a Nissan, which uses the QG18DE engine. See this Wikipedia link on it: Nissan QG engine - Wikipedia, the free encyclopedia

Interesting from Wikipedia are:
HO2S - (4) Oxygen Sensors (2 before exhaust catalyst, 2 after) - note a series 2 1.8l has only 2 o2 sensors 1 pre and 1 post
TWC - Three Way Catalyst (2 in exhaust manifold, 1 under car)
Ignition Timing: 9 degrees BTDC (can be altered +/- 2 degrees using CONSULT-II handheld diagnostic tester, e.g. blaZt)
Knock Sensor - located on engine block; retards timing if pinging/detonation detected.
Heated Throttle Body - heated by engine coolant

I think mine has 2 O2 Sensors.
TWC - why not just one cat converter? More restriction ?
I have the ability to change Ignition Timing +/- 2 - which way is better for fuel economy?

Heated Throttle Body - isn't that the same as a WAI ? - since the air has to pass through it, and Coolant heating the TB would make the mixture heat ?

Now, some feedback to the responses (oh, and yes, it's the very reason that ecomodder is a non product oriented, non biased site, that I posed the question to the talented bunch here.. I do want better FE numbers, and results are results).

The resonator doesn't hold air - Resonator - Wikipedia, the free encyclopedia
It's a sound tool on the intake to reduce intake sound - that's what I took it to mean.

Now, I want to be using the very lowest air fuel mixture possible at the point the car spends the longest - neutral (coasting). When it's accellerating, it's at 2000 RPM tops before changing up (see, I do read and search - in fact, out of 70 posts, I've probably read many hundreds on here since joining looking for anything I can adapt with).

The exhaust was posed as a question for much the reason in the responses... the retail sites claim better performance and fuel economy, I wanted to see the response here.

Isn't more air a good thing (look at it this way: The faster the engine can get up to the desired speed, the more time it will spend idling).

I don't want to risk the battery etc, so I don't want to do Engine Off Coasting - yeh, I realise others do it, but the responses I saw said charging the battery.

I've looked through the mods list, I want more power low down, but don't know how a smaller intake will help that..? The science behind it needs to be explained. Google to the rescue maybe.. ?


http://ecomodder.com/forum/emgarage....&vehicleid=643
Resonators removed out of intake with K&N drop-in air filter.
- Shame he didn't put any FE numbers in.

[Ultra-Orange]

I've wondered much the same things you have. Mainly about the exhaust (considered headers, low restriction cat, free flow exhaust for my metro) I'll be watching this thread with interest. After reading about reducing intake resistance on my Subaru I did a Resonator delete. Admittedly this was done for power purposes.

Just my .02 bits. my understanding is that EoC (Engine off Coasting) isn't terrible for the battery (Though I can't imagine it helps the battery). Rather, Alternator kills or deletes which prevent the Alternator from keeping the battery topped up and completely drain the battery, lead to their rapid demise.

While I have spent most of my life as a gear head, I'm a Ecomodding newbie and most definitely not an engineer so I could be wrong on the above. Just tossing in my thoughts/understanding.

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I found this:
GasSavers.org - Helping You Save at the Pump Hypermiling and Fuel Efficiency Forum - View Single Post - intake resonator

And learnt a little .

Intake resonators are there to help charge more air in at certain RPM ranges. I wonder if that's why I feel my car kick and be better performing when I floor it past 2500 RPM?

Anyway, there are also bad types of resonators - purely for sound deadening.

Autospeed makes similar comments on their blog:
blog.autospeed.com/2003/11/30/those-funny-things-teed-into-intakes/

I still haven't finished getting the communications sorted so I can get some real time data from the car, and the tank is currently 3/4 full and it's just had an air filter change.

The tank will be due for a fill, and perhaps then I can arrange to take out the bottom resonator - leaving the top one on (I think that's the resonator that forces air in). Seal up the gap, and see how it performs.

In the mean time hopefully I can get some more definite answers on it's possible effect (or at least some way to clearly determine it's for noise).
Autospeed blog:
"Note that all of these devices are for noise reduction, rather than intake volumetric efficiency tuning. So if any of the volumes is likely to be causing a restriction to intake airflow (and that’s especially the case with a series expansion chamber), you can delete it without too much concern."

It should reduce pumping losses (suction to get air in)..

A turbo charger might be ideal then? Force more air in from the exhaust cycle, recycling the energy lost to exhaust.. ?

Else, removing the resonator would function like a WAI - though this does now question other WAI tests - where the stock tubing is removed, including resonator.

[jakobnev]

From link in OP:

Took the thing out and went for a cruise on PIE, normally cruise at about 100km/h, after removing the resonator, can go at about 120km/h while stepping at about the same on the accel.

1. the car becomes more responsive upon acc. pad was stepped.
2. Noiser from the engine compartment: bigger hole wat, :P
3. feel like cruising even 70km/h @ 3rd gear.
4. Engine didn't stress that much (my driving behaviour abit terror lah, 1st gear--3K rpm, 2nd gear--4.5k rpm, 3rd gear--3.5k rpm before shift to 5th gear. with this DIY, engine dun sound so stress liao.
5. braking. this is quite important leh, I feel that I need to step harder on the brake after this DIY to actually bring the car to the desire safe distance from e front vehicel while traveling along the high way as compare to b4 DIY. maybe b-cos of the cruising effect?? Did u notice that too?
6. Dun feel the gear "bitting" at all when change from 1st to 2nd"

I suspect it's not just books that can have errors...

[abogart]

This is very interesting. In my case I have an overpowered engine (160 HP V6) for the type of driving that I do. I can get the MAP up to 29"Hg using only about 1/3 throttle in some cases. Somehow I always figured that reducing intake diameter would simply be the same as operating with less throttle. My understanding is that the engine is going to try to fill the cylinders up to whatever the displacement is. Whether air is restricted by the valves (cams), throttle, or intake piping, anything that restricts that air is going to be... Well, a restriction. And I always thought that anything that restricted exhaust lowered output and, therefore, efficiency as well. Apparently my thinking is flawed if some are seeing better numbers by actually adding restrictions.

Would anybody care to elaborate a little further on intake and exhaust tuning?

[drmiller100]

Originally Posted by abogart

My understanding is that the engine is going to try to fill the cylinders up to whatever the displacement is. Whether air is restricted by the valves (cams), throttle, or intake piping, anything that restricts that air is going to be... Well, a restriction. And I always thought that anything that restricted exhaust lowered output and, therefore, efficiency as well. Apparently my thinking is flawed if some are seeing better numbers by actually adding restrictions.

Would anybody care to elaborate a little further on intake and exhaust tuning?

a LOT of this is theory, with suspect application in in the real world.

The intake is as you describe - a restriction is a restriction, and the throttle plate works as good as anything else, so changing the intake for added MPG is probably not going to work.

On the exhaust, for mpg, the argument is you want to keep some exhaust gasses inside the engine for better mpg. the argument is there are pumping losses for a gasoline engine, and the exhaust gasses "fill the chamber" which is more efficient then a vacuum.
Variable cam timing does the same thing - at low speed keep the exhaust valve closed longer to get all the power out of the gasses and keep some of the gasses inside the cylinder.

These are subtle gains, but perhaps they can add some MPG.

[Frank Lee]

Originally Posted by toc

Now, I want to be using the very lowest air fuel mixture possible at the point the car spends the longest - neutral (coasting). When it's accellerating, it's at 2000 RPM tops before changing up (see, I do read and search - in fact, out of 70 posts, I've probably read many hundreds on here since joining looking for anything I can adapt with).

Isn't more air a good thing (look at it this way: The faster the engine can get up to the desired speed, the more time it will spend idling).

I don't want to risk the battery etc, so I don't want to do Engine Off Coasting - yeh, I realise others do it, but the responses I saw said charging the battery.

Idling is the enemy. You don't want your engine to spend much time idling at all.

If you don't have huge electrical loads, EOC won't drain the battery.

Me thinks you need to do more searching here. It's all there; you just have to find it.

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http://ecomodder.com/forum/showthrea...omy-12895.html

A similar question with respect to 'Restriction' was posed in the above thread. The theory there was that reducing pumping losses would improve efficiency. But then 'what kind of car' is probably more relevant.

I do know someone else with an older year pulsar and they've gone with a CAI in front of the car (big 50mm tubing). The engine is a 1.6L and they get near 600kM from a tank (not a good benchmark, but that got me thinking that some performance mods could be for fuel economy too).

[Daox]

Why are you taking this route with mods? You haven't even done any easy mods to the car yet. Start with a grill block, pump up the tires, and get a scangauge. Those few things right there plus a little driving technique will get you a 25% gain at least.

[mcrews]

Originally Posted by Daox

Why are you taking this route with mods? You haven't even done any easy mods to the car yet. Start with a grill block, pump up the tires, and get a scangauge. Those few things right there plus a little driving technique will get you a 25% gain at least.

ditto!!!!!!