Home > Maintenance & Modifications > McNally EGT/Boost gauge. |
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3 Lions Member Since: 11 Jun 2011 Location: Geelong, Victoria Posts: 44 |
Hi,
Has anyone here fitted one of these to a TD5 Defender? They are made by McNally Instruments in the US. The reason I am asking is because I was wondring about the Thermocouple being a 'crush' type rather than a screw in one. I was wondering if anyone had any problems fitting it and finding a suitable place to install the probe on the TD5. Cheers, Col. 1979 Series 3 109 FFR (ex Aust Army.) 2006 Defender TD5 110. 2012 Trackabout CT. |
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14th Jan 2013 6:39pm |
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3 Lions Member Since: 11 Jun 2011 Location: Geelong, Victoria Posts: 44 |
Here you go .... http://www.mcnallyelectronics.com/ http://shop.mcnallyelectronics.com/category.sc?categoryId=3 Col. 1979 Series 3 109 FFR (ex Aust Army.) 2006 Defender TD5 110. 2012 Trackabout CT. |
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14th Jan 2013 7:16pm |
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3 Lions Member Since: 11 Jun 2011 Location: Geelong, Victoria Posts: 44 |
I suppose that would work though, wouldn't it? Col. 1979 Series 3 109 FFR (ex Aust Army.) 2006 Defender TD5 110. 2012 Trackabout CT. |
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14th Jan 2013 7:34pm |
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Steve B Member Since: 22 May 2009 Location: Warwickshire Posts: 586 |
I wouldn't do that, when it breaks its going through your turbo! Needs to be post turbo. Steve |
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14th Jan 2013 7:46pm |
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3 Lions Member Since: 11 Jun 2011 Location: Geelong, Victoria Posts: 44 |
Ooopps! 1979 Series 3 109 FFR (ex Aust Army.) 2006 Defender TD5 110. 2012 Trackabout CT. |
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14th Jan 2013 7:50pm |
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Glynparry25 Member Since: 16 Feb 2009 Location: Miserable Midlands Posts: 3015 |
NOOOOOOOOOOOOOOOO Has to be pre-turbo. Temperature drop across the turbo is massive! http://www.youtube.com/watch?v=RgPHKwoo8fk As you can see from the video the whole manifold is glowing red before the exhaust even starts to show signs of heat. You want to measure where there is most chance of failure- I know on the Toymota Land Cruisers they put it as close to cylinder 4 as possible as that is the one that is the one that melts. Most effective place would be to tap the manifold just before the turbo (where the pipes go to one). But for this you would have to remove the manifold from the vehicle to prevent any swarf getting into to turbo. Easiest place would be into the EGR blanking plate and would give you a good reading as the exhaust gasses traveling from cylinder 1 and 5 will be the hottest. Glyn |
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14th Jan 2013 8:10pm |
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diesel_jim Member Since: 13 Oct 2008 Location: hiding Posts: 6088 |
hmmmm good thinking.
Drilled into the bit of pipe right under the turbo flange then. Or get an old down pipe, cut the flange off of that, then weld it to the flange on the existing downpipe, to make it double thickness. You could then drill it sideways to mount the probe in, and use double length studs. |
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14th Jan 2013 8:11pm |
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Steve B Member Since: 22 May 2009 Location: Warwickshire Posts: 586 |
Hi Glyn, What your saying is correct, you just don't put it pre turbo as the thermocouples do break quite regularly. Our engineers just calculate the temperature loss if you need to know the temperature at the valve. Steve Edit: I will ask the question tomorrow. |
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14th Jan 2013 9:56pm |
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Glynparry25 Member Since: 16 Feb 2009 Location: Miserable Midlands Posts: 3015 |
A thermocouple shouldn't break up providing it is good quality and is checked periodically- a good one is more likely to dissolve/ wear away. Plus I have never seen one break in 10 years of modifying many different cars. The temperature after a turbo can vary massively compared to the manifold depending on your driving at the time. It will not read correct as the temperature goes up (can be 200-300 degC off- as seen in the video) and can have a delay so you have melted a piston or two whilst your gauge is still reading 700 degrees. So I will throw it out there.......... It may break up into the turbo which may result in damage (depending on the size of the pieces)- worse case scenario is buying a new turbo...... or it may read incorrectly and react too slow and you melt piston 1 or 5 (don't really know which is more prone on the TD5 lump) which results in either re-building or replacing the whole engine. There is no way of working out what the temperature will be before the turbo as this will vary depending on the load and style of driving. Glyn |
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14th Jan 2013 10:18pm |
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Glynparry25 Member Since: 16 Feb 2009 Location: Miserable Midlands Posts: 3015 |
Just did a 5 second serch on Google and this is probably the best result:
http://www.supramania.com/forums/showthrea...comparison It is a readout of pre and post turbo temperatures. As you can see there is no way of working out the difference between them both. A couple of graphs for those who can't be bothered to go to the forum: Click image to enlarge Click image to enlarge Click image to enlarge This is just a Supra on the rollers so a Defender with a load/ towing will be even more erratic. Glyn |
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14th Jan 2013 10:30pm |
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me@td5.org Member Since: 16 Jan 2011 Location: Warwick Posts: 856 |
Using the EGR port puts your Thermocouple in the easiest location to fit, and also in the hottest part as the 2 longer outer branches are where the exhaust gasses are slowest.
However Steve is correct, if you are looking for a relative measure of EGT then post turbo is just as good. The values will be much lower but if your pre turbo gasses are hotter you post figures will be proportionally higher. Also worth bearing in mind is that the blanked EGR outlet is a source or turbulence in the manifold which will slow down exhaust gasses and increase temperature. Just look at where they warp. I like the McNally gauge but it isn't much cheaper than a SPA now once you get it over. It's the right colour as well! |
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14th Jan 2013 10:32pm |
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Glynparry25 Member Since: 16 Feb 2009 Location: Miserable Midlands Posts: 3015 |
I must say I prefer the McNally one..... it is so much easier to see what the boost is doing on an analogue style gauge. I have now decided on the Madman EMS2 (if they respond ) Click image to enlarge Does a whole lot more with built in alarms for about the same price (thanks to the current exchange rate). Glyn |
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14th Jan 2013 10:42pm |
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me@td5.org Member Since: 16 Jan 2011 Location: Warwick Posts: 856 |
Maybe someone should get one of these
Fit one sensor upstream and one downstream and tell us what you see! |
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14th Jan 2013 10:45pm |
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Glynparry25 Member Since: 16 Feb 2009 Location: Miserable Midlands Posts: 3015 |
I will if someone is willing to pay for it
Glyn |
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14th Jan 2013 10:46pm |
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