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3rd December 2007, 21:47 | #11 |
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Any idea on the combustion temps that a non egr car reaches versus a car with a functioning EGR and how it compares to combustion temps on a turbo petrol?
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4th December 2007, 00:19 | #12 |
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Wouldn't like to comment on the combustion temperature differences between egr equipped vehicles and those without as it is not only down to that. It's also down to any modification, condition and tune of the vehicle.
Exhaust gas temps for a turbo diesel car should be between 650 and 800 degrees C under full load conditions. The petrol turbo cars should be between 700 and 900 Degrees C under the same conditions. Turbochargers will start too cook over 900 degrees C The best way to minimise combustion temperature is to make the inlet charge as cold as possible. If your intercooler is semi-clogged then it isn't going to be as effective. I've run turbocharged cars both petrol and diesel since they were first available the first being a B type engined SAAB 900 with an mechanical wastegate. (rather than the later variable type). I also currently have a Citroen Activa CT. I've run them in various states of tune and have never had a turbo fail due to overheating. The only turbo failure that I've had has been due to poor maintainence of the oil by a previous owner. Russ |
4th December 2007, 00:47 | #13 |
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Just found some more info. see: http://www.ias.ac.in/sadhana/Pdf2004Jun/Pe1131.pdf
On studies between egr at 0% and 21% open at different loads, show temperature differences of no more than 20 degrees C. to the exhaust gases. The effect on the combustion temperature therefore would not increase to over 900+ degrees C, that would do damage, unless there were other problems. Egr systems also cause an increase of particulate matter(soot)that can have a detrimental effect on the engine and of expelled exhaust gases. Russ Last edited by BigRuss; 4th December 2007 at 00:57.. Reason: spelling |
4th December 2007, 01:57 | #14 |
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Great info chaps, the very reason I started this thread.
Seem to remember a while back someone on here did the Intake Mod and suffered a 3 BHP loss on the rolling road. More interestingly, no one on here has reported any diesel engine failure with all the available tuning mods...............yet.
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4th December 2007, 06:41 | #15 | |
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Further reading....since it is obviously a hot topic elsewhere too: http://www.dieselbob.co.uk/tips.shtml http://www.wynns.be/news.aspx?l=EN&i...iArticleID=826 http://www.aa1car.com/library/egr.htm http://forum.landrovernet.com/showthread.php?t=62808 (Bless 'em Page two is most enlightening!) http://www.pistonheads.com/gassing/topic.asp?t=243418 None of these mention damage to the turbo btw.. Last edited by Zeb; 4th December 2007 at 09:02.. |
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4th December 2007, 09:26 | #16 |
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The whole EGR debate continues to rumble on.
I for one find it increasinly frustrating that there are so many people out there determined to by-pass them or turn them off etc when manufacturers spend so much time and effort getting them into vehicles to help reduce emissions with minimal impact on engine performance and so on. I've just done some test work out in Italy on some diesel engines for emissions and fuel economy and also engine power and the results that I had with a "by-passed" EGR valve or failed unit as is would be viewed are amazing. With the EGR valve working as it should the results were as follows: CO - 0.306 g/km 41.3% of the limit for Type approval for this vehicle. NOx - 0.323 g/km 82.8% of the limit for Type approval for this vehicle. HC + NOx - 0.356 g/km 77.4% of the limit for Type approval for this vehicle. PM - 0.026 g/km 52% of the limit for Type approval for this vehicle (particulate matter). Then for OBD purposes, we have to fail the system or by-pass it to see if the system falls within the OBD limit requirements in this instance, it's fully open like a by-pass system would be. The results are as follows (OBD limits are different, but look at what the TA limit comparison is) : CO - 0.210 g/km 31.2% of limit. So far so good. NOx - 1.783 g/km 457.2% of the limit - so massively over the limit!!! HC + NOx - 1.859 g/km 404.1% of the limit - massively over the limit again PM - 0.161 - 268% of the limit. So as you can see, on a normal drive cycle for emissions testing the results go through the roof and are almost like running a vehicle from god knows how many years ago. Not to mention that the drivablility of the vehicle falls through the floor to begin with until the ECU "smooths" things out and then over a few cycles, the MIL will come on to show that there is a problem in the engine which is then stored in the memory until taken out and should you get pulled for a road side emissions check (which is starting to happen again very soon) they will be able to access your ECU and find out how far you've driven with a defecive EGR valve or other. Fuel consumption also suffers on Phase 1 of the test by up to 1 litre in the urban cycle. Keeping it clean is always a good thing as it improved efficiency, but bypassing it is a real no no in my books. MOT emissions sniffs are just that, sniffs and if you were to put your car through a proper emissions test like the one's I have to witness for type approval, your car would fail the emissions test. for either Euro III which all of our cars are type approved to and they wouldn't even get close for Euro IV. Yes, they are predominantly there for emissions, but given the lengths manufacturers go to fit them into the engines and callibrate them etc with minimal impact on performance costs thousands and many months of development so I hope you can begin to understand why I and my fellow engineers who deal with engine development get totally hacked off when people start by-passing them all for the sake of a few BHP which you're never really going to notice. Sorry, my 2p's worth but from where I sit, they're there for a very important reason. I hope you understand my frustration. Nic
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4th December 2007, 09:35 | #17 |
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Everyone is entitled to their Opinion Rincewind (Nic) that is what this forum is all about.
You make some very Valid points, But the modifications I have now made to my car give me 170BHP on the Rolling Road Tests and give the Car the power I like and it deserves. I personally don't give a Hoot about Emissions (could be because I'm in the states so much), If I get ripped off and have to pay all these green taxes then I will do as I see fit. Only my personnel opinion of course, I don't recycle either. Oops thats me off most peoples Christmas Card list. Nothing listed on E4 either and no MIL Light. Just sailed through MOT with ReMap, Rons Synergy, Air Intake Mod etc. I have not de - cat it yet though. Last edited by JohnDotCom; 4th December 2007 at 09:39.. |
4th December 2007, 09:39 | #18 |
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I take your points Rincewind, however, many people with the egr bypass have non standard engines anyway. eg. Roverron module. Secondly, most people haven't fitted it for bhp but as a way of reducing smoke levels and to avoid reliability issues of what is, after all, an old-fashioned vacuum operated system that clogs up.
John, you will be lynched by the tree huggers... Last edited by Zeb; 4th December 2007 at 09:48.. |
4th December 2007, 09:47 | #19 | |
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When it gets a bit warmer I’m thinking of putting the original EGR back on to see if there’s any difference. |
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4th December 2007, 09:53 | #20 | |
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I'm not the greenest person out there at all and I do appreciate where you're coming from, it's just one of those niggly points that get's me back up a bit every now and then. I'm the first one (money permitting) in the queue for a V8 monster or whatever. MOT is a breeze and any vehicle that's been maintained properly will walk it esp on the smoke side as the tolerance is quite high, but an MOT unit is not quite as sensitive as a full blown Horiba lab and AVL smoke meter plumbed in. I'm going down the Rover Ron route soon but only up to about 150 bhp as I don't trust the bottom end on the 204D2 engine that we have in our cars to take the 170 bhp over a long period of time (hence the reason why Land Rover got the 204D3 engine IIRC that was a bit stronger). Not getting at anyone, it's just the whole EGR things that makes me growl a bit.
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