Do you have VCDS? Sounds like you should if you don't already.  The registered (99USD) version of the freeware, VCDS Lite will do pretty much anything you want on a mk1 Fabia.

Intake air temp is measured by the combined MAP/IAT sensor, so will be affected by EGR activity, but probably very minimally due to the proportion of recirculated gases being quite small.

 

If your 12v doesn't feel responsive and 'eager' I'd say there may be a hiding fault somewhere, they're quite sparkly when running well.

2 hours ago, Wino said:

Do you have VCDS? Sounds like you should if you don't already.  The registered (99USD) version of the freeware, VCDS Lite will do pretty much anything you want on a mk1 Fabia.

Intake air temp is measured by the combined MAP/IAT sensor, so will be affected by EGR activity, but probably very minimally due to the proportion of recirculated gases being quite small.

 

If your 12v doesn't feel responsive and 'eager' I'd say there may be a hiding fault somewhere, they're quite sparkly when running well.

Cool, I will look into it. 

I'm actually pretty happy about the car, it's running really well. I just wanted to see if I'm missing on something by having EGR valve connected.
Today I have tested it and I haven't seen any noticeable effect. Maybe it helps people who have damaged or clogged valve. When I see the hype with so many controversial opinions, I see no other option but to really test it and record the data.

My only complaint is idle, and I don't think anything is wrong with the engine but I personally dislike it. When the engine is not yet 100% warmed up, it idles at about 800-810 rpm (this is after the initial 1000rpm cold). 
The idle at 810rpm is very nice and I like it. But after a while it drops to 750-760 and to me it just seems like it needs this 40rpm more to operate smoothly. It doesn't stall, but It doesn't feel quite smooth. 

Does VCDS allow me to set the idle rev range? 
I don't really need another diagnostic tool because mine is quite decent. But it can't program the ECU. 
 

I forgot to mention that temperature drop with EGR disconnected was pretty insignificant.
It dropped from 37C to 34C and that makes sense to me, because EGR only really needs to add a few % of total volume into the mixture because air is already 80% inert. (although it was much colder outside when I tested 37C)

I will keep tracking the intake temperature, because my next test will be a big cold air intake.
First I will put it like a noob without any insulation just to see what's the difference, then I will make a proper box for it and reroute the air from the front. 

 

You'll notice a drop in fuel economy, an increase in emissions and no improvements at all, a remap might increase power fractionally, but probably no more than 5%.

You're barking up the wrong tree.

3 hours ago, DataLog said:

Does VCDS allow me to set the idle rev range? 

No.

 

If you've already got something that allows you to view temperatures etc., you probably don't need VCDS at the moment.

 

I think you will get a fault light (unless it's been concealed) after a few journeys without EGR working, let us know please.

 

I'm glad to read of your curiosity and willingness to learn about your engine.

 

 

44 minutes ago, sepulchrave said:

You'll notice a drop in fuel economy, an increase in emissions and no improvements at all, a remap might increase power fractionally, but probably no more than 5%.

You're barking up the wrong tree.

I am not aiming for power as much as I'm aiming for fuel efficiency. 
The only way I would've expected better fuel economy from deleted EGR valve would be due to different driving style. As I have mentioned above, I did not feel or test any significant difference. 

My goal with cold air intake is primarily (and everything I'm trying right now) is mainly fuel efficiency. 

 

On the topic of remapping, this engine in stock condition can go safely up to 70hp. Which to me is not insignificant (almost 10%). 
I have no experience in programming vehicle ECU-s, but I do have experience in programming chips. After I try every physical modification, I will start playing with the ECU. 

I'll open a topic on increasing AZQ engine fuel efficiency, so that we have everything in one place. I will also be testing everything stock and after the modification to see if there is any measurable difference. 

36 minutes ago, Wino said:

No.

 

If you've already got something that allows you to view temperatures etc., you probably don't need VCDS at the moment.

 

I think you will get a fault light (unless it's been concealed) after a few journeys without EGR working, let us know please.

 

I'm glad to read of your curiosity and willingness to learn about your engine.

 

 

I'm using KW850  and it allows me to see everything I need at the moment. 
My check engine did turn on after a few trips, but not immediately. I cleared it with my scan tool lol. (it will probably pop up again)

I am still keeping the EGR disconnected, just to check what will happen with fuel economy. I will post an update after 100-150km

As I have mentioned in the comment above, I will do everything that is in my power to try to reduce fuel consumption. If that leads to some power increase by mistake, it will just be another plus.
The only thing I will not tolerate in this pursuit is power decrease.

I did take a trip out to get fuel in the Fabia earlier, and attempted to log EGR activity, but something went wrong with my choice of measuring blocks, or something weird was going on with the EGR valve, I need to try it on a longer journey with some more steady-state conditions.

 

How many km has your car travelled? (sorry if you've already mentioned this somewhere).

4 minutes ago, Wino said:

I did take a trip out to get fuel in the Fabia earlier, and attempted to log EGR activity, but something went wrong with my choice of measuring blocks, or something weird was going on with the EGR valve, I need to try it on a longer journey with some more steady-state conditions.

 

How many km has your car travelled? (sorry if you've already mentioned this somewhere).

89 000

Everything is still in good condition, after 10 000km coolant level didn't change and oil level didn't change. 

Wow, that's almost brand new! My partner's has gone almost three times as far. 

EGR is an efficiency strategy on petrol engines, it significantly reduces pumping losses on part throttle giving real improvements in fuel economy during lean cruise. Deleting EGR can never improve efficiency for this very reason.

Here is some very useful practical information:

 

http://origin.autospeed.com/cms/title_Tuning-for-maximum-fuel-economy/A_113199/article.html

47 minutes ago, sepulchrave said:

EGR is an efficiency strategy on petrol engines, it significantly reduces pumping losses on part throttle giving real improvements in fuel economy during lean cruise. Deleting EGR can never improve efficiency for this very reason.

Please read the whole thread. 

5 minutes ago, DataLog said:

Please read the whole thread. 

 

I read your reasons, put politely they're incoherent which is why I threw you the link. If you follow it up you'll find that what you're looking for is more EGR, not less or none. Ask me why performance tuners delete the EGR system.

1 hour ago, sepulchrave said:

 

I read your reasons, put politely they're incoherent which is why I threw you the link. If you follow it up you'll find that what you're looking for is more EGR, not less or none. Ask me why performance tuners delete the EGR system.

If you've read my reasons, and If you've read my conclusions you wouldn't say that. I found no positive effect after disconnecting EGR valve from my car. 

Also, Wino had a contribution to this. My reasoning didn't apply to the properly working EGR valve. I didn't trust my EGR system. 
I know that there is a lot of controversial thought on EGR valve, and everywhere I look I see someone arguing about it. Not everything is black and white. EGR main purpose (besides emission control) is almost like adjusting the cylinder size depending on the load, and it is a pretty neat invention.

However, you can't really just say it's more efficient without describing why and where. Higher efficiency does not mean less burnt fuel. You can have higher efficiency and burn more fuel (well made race cars are very efficient but they burn fuel like mad).
Given that the engine is optimized for these parameters, it will reach highest efficiency when the engine is as hot as possible and the intake is as cold as possible, because it will get extra compression from the expansion of gasses. Of course, knock should be avoided at all cost. 

I think that the main relevant discussion about EGR has more to do with carbon buildup on the valves, and in my opinion the car manufacturers should've used another route to reduce emissions and increase efficiency just for this reason. It is a fact that higher temperatures prevent carbon buildup. 

Luckily, with manifold/port injection, there is zero carbon build up on the intake valves. I can photograph some very 'mature' ones to demonstrate that, if you like.

Exhaust ports gather a little soot, but not much really, photos just in time for Christmas if tomorrow goes to plan. 

Edited 23 December, 20205 yr by Wino

55 minutes ago, Wino said:

Luckily, with manifold/port injection, there is zero carbon build up on the intake valves. I can photograph some very 'mature' ones to demonstrate that, if you like.

Exhaust ports gather a little soot, but not much really, photos just in time for Christmas if tomorrow goes to plan. 

Yes, that's true. EGR delete greatly depends on the type and age of the vehicle you operate. 

For some vehicles, delete can bring more power and better fuel economy, for newer vehicles it doesn't make a significant difference. 

I would just like to add on the topic of power of EGR that I personally don't believe that Fabia MK1 injects different amount of fuel into the engine depending on the existence of EGR valve because it doesn't have EGR valve flow sensor. I also don't believe that they would risk leaning out the mixture if the EGR breaks down. So my logic is that fuel consumption could be better for old AZQ engine, because the injected fuel will probably be the same, however it could be combusted better without the EGR valve.

Newer engines with EGR flow sensor would correct for this and there wouldn't be any reason for a delete. 

But we'll see after the test. It's a very controversial topic and I think it's controversial because there is truth to the both sides. That's why I don't want to be rigid about it. 

A diesel and not petrol and a later generation engine - EU5, but I have just fitted a DPF emulator to my 2.0 TDi Yeti to stop the EGR operation, I did this after seeing how clogged up things have become after only 80k miles when I had to scrape all the clag out of the throttle valve & upper inlet tract, the lower part will be next after an endoscope inspection, it was also to avoid future breakdowns & costly repairs when the EGR cooler would fail, I appreciate that it still could but its no longer being actioned or passing any exhaust gases so I am hoping that the heat exchanger will remain leak free.

 

Anyway it appears to drive a lot better and appears to be more economical, its only a gut feeling as I am away from home housesitting, driving for sightseeing and not my usual urban journey profile.

 

However I will soon be doing the exact same 750km autoroute journey back as I did to come here, at the same speed (about 80mph) and during the night as before (the curfew hours here in France!) and I got 46mpg on the way down & fitted the emulator the day I arrived  so it will be easy to see if no EGR improves fuel efficiency at cruising speeds, I suspect if there is an increase in economy it will be during urban journeys.

Diesel engines are a whole different ballgame for EGR.  It will be interesting to see the fuel usage figures after your long trip.

 

 

@DataLog, the oxygen sensors will look after the fuelling to maintain lambda=1 during EGR activity. The engine ECU is also aware of the EGR flow via changes in MAP sensor measurements correlated to EGR valve opening/closing amounts.

 

8 hours ago, DataLog said:

I would just like to add on the topic of power of EGR that I personally don't believe that Fabia MK1 injects different amount of fuel into the engine depending on the existence of EGR valve because it doesn't have EGR valve flow sensor. I also don't believe that they would risk leaning out the mixture if the EGR breaks down. So my logic is that fuel consumption could be better for old AZQ engine, because the injected fuel will probably be the same, however it could be combusted better without the EGR valve.

 

The ECU calculates the fuel correction using information from the EGR cycle time because it's controlled by PWM, the MAP and the TPS, so it knows everything it needs to know to apply an algorithm.

These things are not a matter of faith or belief, they are cold hard facts.

You are not controlling the engine, the ECU is, it's completely FBW.

6 hours ago, Wino said:

Diesel engines are a whole different ballgame for EGR.  It will be interesting to see the fuel usage figures after your long trip.

 

 

@DataLog, the oxygen sensors will look after the fuelling to maintain lambda=1 during EGR activity. The engine ECU is also aware of the EGR flow via changes in MAP sensor measurements correlated to EGR valve opening/closing amounts.

 

Unfortunately I won't be able to test this properly without additional modification. 
I've scanned the codes and it turns out that EZQ engine determines whether there is EGR flow by measuring the temperature of returning exhaust gas. This means that the engine is aware that the EGR is closed.
I am not sure what the ECU will be doing now. Maybe it compensates for it, maybe not. In some cars ECU can even reduce the power if EGR is disconnected without a remap. I could trick the temperature sensor, but I don't want to do it now. 

I talked to my friend mechanic, who is also tuning cars and he personally doesn't see the purpose of EGR in petrol engines. It's a different story for diesel engines because they emit a ton of NOx gases. 
I also don't see the point of NOx reduction in gasoline cars as NOx is already very low. Combating vacuum losses for efficiency makes sense, but those losses are not as significant in petrol engines as in diesel engines. 

I will still proceed with the test to see what will happen with the fuel consumption, but the test will not be relevant for every car. Only this particular setup. 
So far I haven't noticed any change in power, but removing EGR should give an increase in power in older engines. Especially if you have an old school vacuum operated EGR, because the gas pedal can't shut it off electronically. You can only shut it off with completely opened throttle. 

The pumping losses are far higher in petrol engines than diesels, you've got that the wrong way round.

7 minutes ago, Wino said:

The pumping losses are far higher in petrol engines than diesels, you've got that the wrong way round.

Probably due to higher rpm, but shouldn't the vacuum per stroke be greater in diesel engine? 

28 minutes ago, Wino said:

The pumping losses are far higher in petrol engines than diesels, you've got that the wrong way round.

Probably due to higher rpm, but shouldn't the vacuum per stroke be greater in diesel engine? 

My mistake. I was going by the high compression logic. 

What vacuum? Diesels regulate fuel to control power, rather than airflow.