Home > Technical (L322) > 3.6 TDV8 EGR options? |
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Cam-Tech-Craig Member Since: 03 Aug 2011 Location: Gloucestershire Posts: 16284 |
Read the post below yours then sir... |
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10th Aug 2014 9:19am |
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Stephen.Gazard Member Since: 10 Apr 2012 Location: Bristol Posts: 192 |
I reiterate ... Unless you effectively want to sink the cost of a replacement engine plus labour ..... bite the bullet and get the EGRs done as soon as they start playing up ...... any bank balance can vouch for it ! Stephen Gazard
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10th Aug 2014 9:28am |
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Mikey Member Since: 10 Jan 2008 Location: Dundee Posts: 1751 |
The EGR is there to lower combustion temps (due to less oxygen to burn, effectively strangling the engine)
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10th Aug 2014 3:04pm |
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milesg Member Since: 18 Dec 2013 Location: Gloucestershire Posts: 120 |
guys, as someone who experienced catastrophic engine failure in another marque due to a £5 crankshaft bearing deciding to let go after just 60k miles I am all for preventative modifications, how much does mapping it out cost and who does it, preferably in the SW / Midlands?! |
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10th Aug 2014 4:39pm |
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TheAllSeeingPie Member Since: 18 Apr 2012 Location: Leeds Posts: 848 |
An EGR stuck open while on boost means the extra gases being forced into the exhaust system get forced into the engine, which increases pressure which subsequently over speeds the turbo. The faster turbo then creates more boost which means higher combustion temps due to more oxygen. Sometimes the turbos wastegate can prevent this, but the wastegates on a diesel aren't huge so can't relieve all the pressure.
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10th Aug 2014 8:55pm |
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TheAllSeeingPie Member Since: 18 Apr 2012 Location: Leeds Posts: 848 |
As for mapping try Viezu v-box as that means you won't have to travel. Alternatively I think Alive tuning are down that way? Any mapper who can write the tunes should be able to do it, avoid anyone who just seems to load on stock maps.
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10th Aug 2014 8:57pm |
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Mikey Member Since: 10 Jan 2008 Location: Dundee Posts: 1751 |
If this were the case, then there would be a whole lot more TDV6 D3/RRS with blown engines... The turbo is a VNT unit on the TDV8 (and the TDV6), which is an electronically operated unit. As soon as the PCM sees too much boost, it backs the turbo off to lower the boost pressure. If it can't lower the boost pressure via the turbo, it cuts the fuelling, to lower the boost. In either of those cases, an Engine System Fault warning would be displayed In the case of an EGR stuck open, the turbo lag is increased hugely due to the engine not being able to burn cleanly, as it is not as efficient, due to the lack of oxygen inside the cylinder. Less oxygen = cooler burn, the whole point of the EGR system. When the turbo pressure exceeds the pressure of the gas flowing through the valve, the EGR is then redundant, and the gas will not flow anywhere. |
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10th Aug 2014 9:11pm |
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TheAllSeeingPie Member Since: 18 Apr 2012 Location: Leeds Posts: 848 |
That's only if the turbo isn't coked up from a failing EGR. If the EGR is allowing soot build up in the engine then you'll get VNT issues as described here http://www.turbotechnics.com/www/?page_id=430. The blown turbo / happens if the turbo over speeds, the alternative is compete loss of power, however in our cars I was assuming people would jam the turbo open as we need more revs to get moving.
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11th Aug 2014 5:02am |
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Mikey Member Since: 10 Jan 2008 Location: Dundee Posts: 1751 |
But you can't jam the turbo open on a TDV8. It is all electronically controlled, to protect itself. Not to mention a fairly major operation in itself to access the turbos!
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11th Aug 2014 5:45am |
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Cam-Tech-Craig Member Since: 03 Aug 2011 Location: Gloucestershire Posts: 16284 |
Speaking to Midland Turbo's part of the issue is the electronic unit... JLR bought a perfectly good proven unit from Garett then threw away the perfectly good proven mechanical actuator unit and had their own electronic units made! This is now far more unreliable then the original units (sticking shafts etc which incidentally leaves the unit sticky in one position)
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11th Aug 2014 7:51am |
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Mikey Member Since: 10 Jan 2008 Location: Dundee Posts: 1751 |
I will agree with your first statement
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12th Aug 2014 6:32am |
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Mossy1985 Member Since: 20 Nov 2014 Location: Durham Posts: 2 |
Interesting read guys, it is my first post but relevant as my dads tdv8 has got egr issues. I'm intend to blank them off and have the vehicle mapped as a mate of mine has a business who does this. The reason I joined the forum was to see if anybody knew of a company/person who made blanking plates for the egr valves? I don't see why anyone would be stupid enough to have there egr valve open constantly? Ie mapped to have it that way. You just blank the feed from exhaust side and blank the port where it re-enters the inlet, job done. I did this on my bmw 330 d m sport and when I removed the inlet omg the crud inside was terrible. I removed the full inlet manifold filled with drain cleaner mixed with gunk and left for 24 hours then swilled out. Egr is awful design unless it runs through a cooler first but a lot of engines are hot egr
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20th Nov 2014 8:33am |
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Cam-Tech-Craig Member Since: 03 Aug 2011 Location: Gloucestershire Posts: 16284 |
Dave, firstly welcome sir
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20th Nov 2014 8:44am |
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Mossy1985 Member Since: 20 Nov 2014 Location: Durham Posts: 2 |
Thank you for the welcome and your thoughts. The mapping out isn't an issue my mapper tells me? I find it strange that no one has blanked it off before as that's all people do on all other makes and models that I'm aware of? And like I said earlier its what's did on my bmw, however that was a vacuum operated system but the vacuum was still operated by the ecu via a control valve so I would think it is the same principle? The reason this has come up is that the eml is on due to one of the egr valves. He planned on getting it mapped when he first bought the car so his thinking is if he is getting it mapped regardless and one valve is faulty then just blank the pair and map them out.
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20th Nov 2014 11:27am |
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