VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => IDI Engine => Topic started by: Gernster on October 01, 2008, 02:05:44 am
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Have bought myself an EGT guage (& Boost) whilst my head is off.
Looking for the best place to drill & tap on a 1.6 GTD (SB/RA) exhaust manifold. I know I need to get close to the Turbo, but can you get too close??i.e should I be fitting right next to the turbo joint ot after the bend as it goes down to the downpipe?
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Nope,that will give false readings .It will be cooler there by hundreds of degrees.You need it in the the combined stream in the exhaust manifold,preturbo.
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Put 'er here:
(http://i192.photobucket.com/albums/z236/dieselkraftstoff/SSPX0007.jpg)
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I put mine at the junction of the 3 & 4 runners. My first attempt resulted in a cracked manifold - so I used the drill press after I welded my crack. Here's my post on that - towards the bottom.
http://www.vwdiesel.net/phpBB/viewtopic.php?t=15633&postdays=0&postorder=asc&start=0
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The standard transverse manifold can easily be drilled with an electric hand drill.
Cobalt bits go through it like a hot knife through butter. Make sure to cool the bit with some oil, WD40 works great.
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thanks guys, good job I asked!
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I see arb used high temp sealant. Did anyone not use any sealant? just drill tap and thread it in?
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The Spruce and VDO thermocouples (The spruce thermocouple is the fastest) have pipe thread adaptors.
Pipe thread is tapered.
No sealant required.
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dont forget your antisieze....
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dont think I'll ever have cause to remove it mate ;)
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Dont think youll remove it huh?
Seems easier to put the antisieze on that it will be to get back on here and ask how to get it out without damaging it.... :D
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What about on a non-turbo'd rig? should it still be on the manifold, or can it be down on the pipe within the first foot or so of the block? Just wondering because I don't have a welder to fix my manifold if it cracks when tapping it for the probe. Picture for reference?
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Put it in the manifold.
I've never seen one crack due to drilling/ tapping.
The sender needs to be as close to the head as possible and in the combined exhaust stream.
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The sender needs to be as close to the head as possible and in the combined exhaust stream.
Why do you say that? If your running 1000 Degrees F in one cylinder, measuring two cylinders simultaneously won't show 2000 degrees. :P
Or is the probe in more exhaust so that makes it more accurate?
Seems to me if you put it too far from the head just to get all four cylinders it would read cooler because of the extra distance from the head.
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The sender needs to be as close to the head as possible and in the combined exhaust stream.
Why do you say that? If your running 1000 Degrees F in one cylinder, measuring two cylinders simultaneously won't show 2000 degrees. :P
Or is the probe in more exhaust so that makes it more accurate?
Seems to me if you put it too far from the head just to get all four cylinders it would read cooler because of the extra distance from the head.
Correct it wont read 2000 deg, if you only stick it in the stream of one or 2 ports you wont know what the others are doing. If you have 3 cyl running 600 and one running 1200deg it will show up on your EGT as a higher reading than the 600 deg thus the "Combined stream" application.
You are looking for a average here.
I said in the combined stream as close to the head as you can get so the average you are reading is more accurate, yes the farther from the head the colder it will read.
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If you have 3 cyl running 600 and one running 1200deg it will show up on your EGT as a higher reading than the 600 deg thus the "Combined stream" application.
Good point, so if you got one injector with a bad spray pattern or whatever it "should" show up, then you'd have to guess at which one it is. I'll keep that in mind for when I drill the mani for my vnt-15.
Probably drilling 6inches from the head were they all meet won't affect the reading too much anyhow as the exhaust gasses are moving perdy fast.
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And tapping one for each cyl would probably be overkill, esp on my stock '81 1.6 NA. and by the time i get to upping the power it'd be better to upgrade to custom/ceramic coated headers anyway, right?
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If you have 3 cyl running 600 and one running 1200deg it will show up on your EGT as a higher reading than the 600 deg thus the "Combined stream" application.
Good point, so if you got one injector with a bad spray pattern or whatever it "should" show up, then you'd have to guess at which one it is. I'll keep that in mind for when I drill the mani for my vnt-15.
Probably drilling 6inches from the head were they all meet won't affect the reading too much anyhow as the exhaust gasses are moving perdy fast.
One bad injector WILL show up as a hole in the piston..... :shock: not on the egt gauge. Especially if you push your egts!
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If you have 3 cyl running 600 and one running 1200deg it will show up on your EGT as a higher reading than the 600 deg thus the "Combined stream" application.
Good point, so if you got one injector with a bad spray pattern or whatever it "should" show up, then you'd have to guess at which one it is. I'll keep that in mind for when I drill the mani for my vnt-15.
Probably drilling 6inches from the head were they all meet won't affect the reading too much anyhow as the exhaust gasses are moving perdy fast.
One bad injector WILL show up as a hole in the piston..... :shock: not on the egt gauge. Especially if you push your egts!
It WILL show up on the gauge LONG before there is a hole in the piston.
Providing you are starting out with a healthy engine you will have a baseline, using that baseline you will know if there is a problem. Your EGT's will go up even with one bad injector.
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The sender needs to be as close to the head as possible and in the combined exhaust stream.
Why do you say that? Seems to me if you put it too far from the head just to get all four cylinders it would read cooler because of the extra distance from the head.
Yup.. your exactly right.. :D
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ok, apart from diagnosing a bad injector, lets say you have an egt guage to keep a general idea on how your current "tune" is affecting things.
i'm still using the stock k14 turbo on my aaz with stock manifold, which is the 3 bolt type with flange on the end just outside number 4 cylinder for EGR stuff.
now, i will be sticking my egt probe in the junction when i change to t3 and a 4 bolt mani soon, but for now its mounted in a blanking plate where the egr used to be. i see good response on the guage (within the same gear) and so far max EGT i've seen has been 520C (970F) (20psi, accelerating at WOT 4th gear up hill to 70mph).
i figured that since (when it counts) the pressure inside the exhaust manifold must be around 30psi and large flow rate, that the probe, wherever its placed, should give a reasonably good reading, even though its only behind 1 exhaust port.
thoughts?
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This manafold (pictured)
seems to be different than mine.
I have Garrett T3 (OEM)
and I dont think I have a boss where that one was placed.
Can I use the boss for the heat shield mount (Just a little closer to the turbo flange than the one pictured)?
I am installing a spruce thermocouple (Thanks, GTD!)
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Where is a good place to get these and what brand should I go for?
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People seem to like the aircraft spruce thermocouple. It reacts quickly and is reasonably inexpensive.
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Here's the Aircraftspruce superfast probe:
Link: Aircraftspruce (http://www.aircraftspruce.com/catalog/inpages/micro8egt.php)
(http://www.aircraftspruce.com/catalog/inpages/inmisc/10-01475.jpg)
And here is a VDO EGT gauge:
Link: VDO Vision EGT Gauge (http://www.egauges.com/vdo_mult.asp?Type=Pyrometer&Series=Vision&Units=E)
(http://www.egauges.com/images/vdo/310-151.jpg)
You'll need the lead wire, so you can either buy the gauge with the super slow VDO probe and use the supplied lead wire.
Or contact Libbybapa and see if he is still selling bulk thermocouple lead wire.
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I have that setup and it works great!
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I have the AS probe and gauge just waiting to be mounted and used...
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I ordered prothe's egt gauge and sender. Anyone use this one?
http://www.dieselvw.com/EGTGauge.htm
I think it's hilarious that it goes to 2,400 and then says "warning" after that.
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Well it says "Type R" so it must be good..