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Engine Specific Info and Questions => IDI Engine => Topic started by: BellCityDubber on November 14, 2006, 01:55:47 pm
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So I've decided to get an EGT gauge and probe kit...
Now my quesiton is this:
I know that alot of people recommend pre turbo and a few like post turbo due to turbine saftey concerns. Although it will potentially save my turbo, and I'd have to add ~200* to my EGT reading.... where on my 1.6TD's downpipe should I place the bung?
Anyone have any suggestions or pictures they could share?
thank you
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Pre turbine isn't that hard. Ive done a couple. Unbolt your exhaust manifold. Take your probe adaptor to your local hadware store and get the appropriate tap and a couple of cobalt bits to drill the hole. Drill and tap in the center of the manifold below the turbo flange. I have one manifold that I did this to about 5 years ago. Many hard miles with no problems. Even saved my engine once when I hit a bird at speed. Grill/bird parts some how got into the timing cover, under the belt and had the pump retard one tooth. Holy high EGT bat man..
Post turbine EGT is a guess at best.
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Post turbine also respomds much more slowly.
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That's a nice suggestion and all, but unbolting the exhaust manifold is more work than I'm really willing to do at the moment, seeing as the car probally hasn't been apart since nineteen ninety-never, I dont want to break a stud and render my daily driver undriveable until I have the money and time to fix it. (I've had it happen on my old audi)
From what I've been told by a vw/audi tech who's in my car club, there are quite a few audi's that have their egt gauge post turbine. which is fine enough for me. which will also give me the added benefit of not damaging my turbine in the event of the probe breaking inside the exhaust system
IMHO, it's difficult to find some of the 1.6TD parts [around my area] so instead of having someone fab up a manifold in the event of a screw up (not saying he does bad work, but I just want to be certain) I'd rather mess up the downpipe, then in that case I can order one from passenger performance.
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Saurkraut mentioned about drilling and tapping...
although I'm not the one doing that portion of the install, would drilling a hole and welding in something like an O2 bung be sufficient?
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I'm using a band clamp style one and that's been sufficient for a couple thousand km's so far (and a dab of JBweld) so I'm sure a bung will be 100% fine for the next 200 years.
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Grill/bird parts some how got into the timing cover, under the belt and had the pump retard one tooth. Holy high EGT bat man..
:shock: WTF?? That had to make quite a mess...
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I'm using a band camp style one ...
What? Band Camp? ;)
jk
Ok ok
On a serious note...
I tried searching because I remember a post with a picture of someone mounting an egt probe in the bottom of the manifold in one of the bracket support bolt holes.... does anyone recall this post by chance?
I tried searching and couldn't find it
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I faintly racall, somewhere, that some one drilled their exhaust manifold on the vehicle with the engine running to blow the chips out while drilling.
I wouldn't fret the exhaust studs. Typically, if the nut won't thread off the stud, the stud will will thread out of the head just fine. Get a bag full of new studs and nuts and go at it.
With the way these manifolds warp, everything is probably loose already.
Fear not the drilling and tapping as well. The cobalt bits go through the manifold like a hot knife through butter. The tapping is a breeze too. Just did one last weekend.
I use the VDO stuff, so if you want to know the drill and tap sizes, i got all the stuff in my car and i'll go out and get the sizes for you.
If you want a nice little gauge that shows a temperature, go post turbo.
If you want to measure EGT for engine mods, put it in the manifold.
Going through the bracket hole looks good in the pictures, but it looks kind of scary when you have the manifold in you hands. puts the hole mighty close to the turbo mounting flange surface. I'm fearless, but it scared me.
Take your best guess were the center on the bolt pattern is on the bottom and drill away.
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With the way these manifolds warp, everything is probably loose already.
That's true, Nos 1 and 4 on mine were 0.040" ish above the centre two... No.4 bolts loose and blowing. Took a few hours with 80# to get it all level again.
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So I've decided to get an EGT gauge and probe kit...
Now my quesiton is this:
I know that alot of people recommend pre turbo and a few like post turbo due to turbine saftey concerns. Although it will potentially save my turbo, and I'd have to add ~200* to my EGT reading.... where on my 1.6TD's downpipe should I place the bung?
Anyone have any suggestions or pictures they could share?
thank you
I've yet to hear/read a convincing argument for not installing an EGT post turbine. My TC mounts in a bung in the downpipe as close as possible to the exhaust flange, with the probe tip centered in the pipe.
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[/quote]
I've yet to hear/read a convincing argument for not installing an EGT post turbine.[/quote]
Here's one: post turbine you have absolutely no idea what temperature the turbine is actually seeing or what is coming out of the engine (which also has an EGT limit based on the composition of the exhaust valves correct?). The energy absorbed by the turbine is not a constant so there is no easy "add 200F" formula.
Use a thermal couple that is rated to well beyond your max allowable EGT and drive worry free, or don't use a gauge at all and drive worry free since you are already doing so by having it in the downpipe ;)
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I've yet to hear/read a convincing argument for not installing an EGT post turbine.[/quote]
Here's one: post turbine you have absolutely no idea what temperature the turbine is actually seeing or what is coming out of the engine (which also has an EGT limit based on the composition of the exhaust valves correct?). The energy absorbed by the turbine is not a constant so there is no easy "add 200F" formula.
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Have you actually measured exhaust gas temperature pre and post turbine?
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At low boost levels there is little difference in pre and post turbine temps, at high boost levels there is a big difference, the one place you want/need it to be accurate is the place that it's least accurate.
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No I personally have not. However just because I haven't doesn't mean that I don't have reasons based on facts such as the turbine sucks vast amounts of energy (heat) out of the exhaust flow to believe that the readings are virtually useless post turbine.
The only application I know of where a EGT probe(s) are used post turbine are jet engines which run in a vary narrow power band and have all the variables already calculated by the manufacture of the engine. The temperature limits are therefore useful since the engine max temps are meant to be measured post turbine.
In our case the turbos all have INLET limits so unless you mount a probe pre in addition to post, map out the difference between the two under all conditions (for each set up you run) and run a calculation in your head based on the difference...the post results will be totally useless for being used a gauge of turbo health.
To each there own but other than the slight chance of breaking off my 1" long probe (rated to 2100F) there is no reason not to have it pre turbine and actually read the proper temperature.
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No I personally have not. However just because I haven't doesn't mean that I don't have reasons based on facts such as the turbine sucks vast amounts of energy (heat) out of the exhaust flow to believe that the readings are virtually useless post turbine.
The only application I know of where a EGT probe(s) are used post turbine are jet engines which run in a vary narrow power band and have all the variables already calculated by the manufacture of the engine. The temperature limits are therefore useful since the engine max temps are meant to be measured post turbine.
In our case the turbos all have INLET limits so unless you mount a probe pre in addition to post, map out the difference between the two under all conditions (for each set up you run) and run a calculation in your head based on the difference...the post results will be totally useless for being used a gauge of turbo health.
To each there own but other than the slight chance of breaking off my 1" long probe (rated to 2100F) there is no reason not to have it pre turbine and actually read the proper temperature.
I rest my case.
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You rest your what? Total lack of understanding...ah I see.
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You rest your what? Total lack of understanding...ah I see.
I asked if you have measured egt pre and post turbine. You haven't. And telling me that a turbine absorbs "vast amounts of energy" doesn't answer my question.
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How can you think that it's the same or if you can't even estimate how much is absorbed? Therefore post temps are absolutely useless. No other way to put it. You could be running close, maybe it's 100F difference, maybe it's 350F difference, but how do you know? Why bother having a gauge if you have no idea if the data it throws in your face is anywhere close to accurate or is questionable at best. Seriously if someone wants to give me $50 I'll order another EGT probe the same as I have and mount it in the down pipe on a toggle switch so I can determine what the difference is on my setup with my turbo. It'll be useless numbers for your set up though since the variables such as turbo efficiency are not the same.
If you think you need an EGT gauge it should be done so it actually shows the actual factual EGT. If you can't see that there is no one size fits all formula by now there is no point in continuing the conversation on pre vs post.
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I asked if you have measured egt pre and post turbine. You haven't. And telling me that a turbine absorbs "vast amounts of energy" doesn't answer my question.
I have. Only because I got a truck that already had a probe in the downpipe.
Slave is right.
You should not go pre turbine because it is a waste of your money.
Akin to buying a Ferrari and only using third gear.
Unless you got your guage for free, and don't give a crap about your engine.
Here's why:
A) Aluminum melts at 1450F and your pistons are aluminum.
B) High EGT will burn the tips off the hot side turbine.
C) EGT damage is cumulative.
D) It costs more and take loger to replace a piston than a turbocharger.
Post turbine measurements are about 300% slower than preturbine, and may read low by more than 25%
So when you leave the line, and your EGT hits 1400F(danger) your guage may read 1000F(looks hunky dory) twenty seconds later. I like to think most of us can get fairly far down the track in 20 seconds. Climbing a hill is even more dangerous.
I asked my Dodge expert(20 yeas as Cummins tech) the best way...He drills the manifold on the car. If you drill carefuly, the shavings are all small enough to pass harmlessly through the turbine. I was afraid, and removed the manifold anyway(also had to replace a broken bolt). Still, he did it in his 7000+ LB daily driver that runs low 12s, I think his turbo is fine.
With the probe being encased in stainless steel which takes much higher temps than most of the other componens, risk of disintegration is pretty negligible.
In short, POST(edit) turbo EGT guage is a waste of dash space.
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In short, pre turbo EGT guage is a waste of dash space.
Duuuuuude.... nice sarcasm! :D
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How can you think that it's the same or if you can't even estimate how much is absorbed? Therefore post temps are absolutely useless. No other way to put it. You could be running close, maybe it's 100F difference, maybe it's 350F difference, but how do you know? Why bother having a gauge if you have no idea if the data it throws in your face is anywhere close to accurate or is questionable at best. Seriously if someone wants to give me $50 I'll order another EGT probe the same as I have and mount it in the down pipe on a toggle switch so I can determine what the difference is on my setup with my turbo. It'll be useless numbers for your set up though since the variables such as turbo efficiency are not the same.
If you think you need an EGT gauge it should be done so it actually shows the actual factual EGT. If you can't see that there is no one size fits all formula by now there is no point in continuing the conversation on pre vs post.
What I am saying is, nobody, including yourself, has provided compelling evidence that there is not a functional and useful relationship between pre-and post-turbine temperature. On the other hand, I've read several places that pre/post delta Ts are about 200 - 300 F. If you were really that concerned about egts, you'd have a probe at each cylinder exhaust port proximal to the exhaust valve. What you are measuring downstream pre-turbine is the integrated temperatures of all cylinders minus losses to the exhaust manifold. Then there is the issue of TC lag. A TC has thermal mass and doesn't respond instantly to temperature changes; spikes get integrated out. For all these reasons, and the possibilty that a probe could break and be ingested by the turbo (just because the TC is rated to 2,100 F doesn't mean it can't mechanically fail through fatigue), is why I locate my TC post turbine.
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I think replace pre with post in that post 2 above...
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Will some one do a search to see if there is any evidence of pre turbo probes snapping off and destroying the turbo.
I spend way too much time stairing at diesel crap on the internet. I have yet to see any evidence of preturbo thermocouples disintgrating and wreaching havoc on poor defenceless turbos.
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Post turbine measurements are about 300% slower than preturbine.
Really? If post-turbine measurements were just 100% slower, they wouldn't be changing at all.
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I have been offered one here in England,
300458 Westac EGT sender 1/2" tip
That requires an M8x1 thread in the manifold and protrudes 17mm
Does this seem a reasonable size compared to the ones that Aircraft Spruce offer ?
Is 900C high enough, or would it be best to see 1000 or more?
Thanks for any answers :)
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900c is 1652f, so it should work.
VDO has pyro kits. i like them because you get everthing for the install, and their black face gauges match the VW stuff
http://www.egauges.com/vdo_mult.asp?Type=Pyrometer&Series=Vision&Units=E
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If million dollar jet engines have the TC PRE turbine section in many cases I think I'm safe with the VW diesel and the probe pre. If you size the TC appropriately it won't fatigue from vibrations.
There is only 1 case I know of with a pre turbine TC failing and it was bent up like a pretzel so it could be used in an EGR block off plate on a TDI. It would have been ~4" long. something like that certainly see exponentially more vibration than a 1" long TC. The lucky Fin that it happened to said the VNT vanes stopped the TC from going through the turbo since such a large chunk of it broke off.
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LOL I typoed.
Post turbo takes 3 times longer to react.
while you are protecting you engine from those little probe peices, you probably should get rid of the glow plugs too right?
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LOL I typoed.
Post turbo takes 3 times longer to react.
while you are protecting you engine from those little probe peices, you probably should get rid of the glow plugs too right?
Hmmm...How do you make a "typo" between the % sign and the word "times?" Glow plugs are a necessary risk. The car won't cold start without them. A pre-tubine EGT probe isn't.
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If you can't afford to take the risk of having the EGT probe Pre- turbine, you can't afford to play. In which case you are stock, and you don't need a pyrometer. :wink:
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If you were really that concerned about egts, you'd have a probe at each cylinder exhaust port proximal to the exhaust valve.
No you wouldn't, the weak link as far as high temps are concerned is the turbine, the pistons are oil cooled, they can take the heat, that's why the turbin inlet temp is the only thing that is of any importance.
What I am saying is, nobody, including yourself, has provided compelling evidence that there is not a functional and useful relationship between pre-and post-turbine temperature.
Uhhhhh,
At low boost levels there is little difference in pre and post turbine temps, at high boost levels there is a big difference, the one place you want/need it to be accurate is the place that it's least accurate.
But hey, If you like gauges that have massive inaccuracy at the most critical moment thats cool too. HOw about a tach that read correctly between 1000 ans 2000 RPM, but at 5000 rpm it reads anywhere from 800 to 2000 RPM to low? But you neve know how much it's reading off, sound good? that's what you think is good for an EGT gauge...
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If anyone is interested, I've done some calculations on turbine deltaTs and am in the process of checking them more thoroughly. Interestingly, I've run a few cases and get about 200 deg F, the same number I've read elsewhere.
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If you can't afford to take the risk of having the EGT probe Pre- turbine, you can't afford to play. In which case you are stock, and you don't need a pyrometer. :wink:
uh uh...Giles modded pump, GTD nozzles, 2.25" free-flowing exhaust, manual boost controller (15 psi boost), cold air inlet, thermostatically controlled, fan-cooled intercooler, EGT :wink:
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At low boost levels there is little difference in pre and post turbine temps, at high boost levels there is a big difference, the one place you want/need it to be accurate is the place that it's least accurate.
I hardly call that compelling. :roll: Show me some actual numbers or thermodynamic equations that support your ideas.
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At low boost levels there is little difference in pre and post turbine temps, at high boost levels there is a big difference, the one place you want/need it to be accurate is the place that it's least accurate.
I hardly call that compelling. :roll: Show me some actual numbers or thermodynamic equations that support your ideas.
TDIMeister ran all those calculations a while back on TDI club to illustrate that post turbine placement is fairly worthless, he knows more about this than all of us put together, he does this stuff for a living, I'll take his word on it over yours any day of the year.
EDIT- You are determined to put your probe post turbine, do it, you'll never convince us its better, and we'll never convince you that pre turbine is the way to go...
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300% longer is actually equal to 3 times longer.
Yes, you are correct. Something can't be more than 100% shorter than another thing or it wouldn't change, exist, etc.
I'm not so interested in the calculations on paper, but rather actual pre and post turbo measurements.
Me as well, which is why I'm asking the question, which incidently, nobody here has answered. However, I find it interesting that my calculations give deltaTs close to commonly cited values.
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YUp,
Put it post turbine, rig up a temporary pre-turbine instrument, calibrate the post-turbine one against it for steady-state at various boost levels and rpm...
but the lag will always be there, and the boost/rpm correction read-off tables too!
Maybe a HUD unit would come in useful for their display :roll:
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The readings are actually 300% slower if you use an inline flux capacitor.
But that's in 4th gear, in lower gears you have to multiply %300 by the gear ratio, in 1st it responds about %1000 slower, in 5th it actually responds a little quicker than %300.
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At low boost levels there is little difference in pre and post turbine temps, at high boost levels there is a big difference, the one place you want/need it to be accurate is the place that it's least accurate.
TDIMeister ran all those calculations a while back on TDI club to illustrate that post turbine placement is fairly worthless, he knows more about this than all of us put together, he does this stuff for a living, I'll take his word on it over yours any day of the year.
EDIT- You are determined to put your probe post turbine, do it, you'll never convince us its better, and we'll never convince you that pre turbine is the way to go...
jackbombay, I don't know you. But I'm not trying to convince anyone or put people down. I just have a tough time accepting something without solid proof. I'd simply like to see numbers to back up the claims. :mrgreen:
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Where did you get convinced that the probes fall apart prior to other significant engine damage? What numbers convinced you of the viability of that scenario?
Andrew
Who said anything about other significant engine damage? Probes are often encased in stainless steel. Stainless steel, depending on the grade, is prone to vibrational cracking, especially at elevated temperatures. A friend and expert stainless steel fabricator steered me away from 304ss for my downpipe for that reason. 321ss is a better choice. I honestly don't know which stainless my probe is made from, but I was involved in high-temperature engine seal development and saw Type K probes break when they were repeatedly exposed to temps of about 1,600 F and little vibration. The cases became brittle. We replaced quite a few.
Look at it this way: If I am flying a Space Shuttle, there are hundreds of critical-one components, those which failure of could compromise the ship and crew. If engineers decided a probe could be relocated to eliminate one of those failure modes, and still give them the information they desire, would they not do it? On the other hand, if the probe's location were absolutely essential to its proper operation, then they accept the risk. Though my 92 Jetta Ecodiesel is far from a Space Shuttle, the same principles apply. A failed $30 probe could likely destroy an $800 turbocharger. Conversely, if I can get the info I need without the risk, I'll do it.
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You are right. No one has mounted two thermocouples on their engine and recorded these measurements. I doubt anyone ever will, except Slave2School. He clearly offered to do it for fifty bucks. So there is a valide offer to produce the data you desire.
Equally, no one here will say its ok to put it in the down pipe and use it for engine monitoring. Say what you want, rant on... your not going to get it here. Also, I used to fly jets for the navy, worked for aerospace frims offering temperature measurement for miltary, commercial and space applications, and my probe is preturbo, and I'm fine with that
You could do a poll, and see how many are pre turbine, what the milage is, and what the mods are. There is no evidence on this forum of probe failure in the pre turbo installation. I've probably put 150K miles on my preturbo probe, I drive it like i stole it, and the probe is fine.
Somewhere on Freds page, TDImeister has done some calculations. Search it out and see if its what you seek.
Or go post turbine, mentally subtract 200 or 300 degrees (your choice) from you gauge measurements and hope for the best.
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You are right. No one has mounted two thermocouples on their engine and recorded these measurements. I doubt anyone ever will, except Slave2School. He clearly offered to do it for fifty bucks. So there is a valide offer to produce the data you desire.
Equally, no one here will say its ok to put it in the down pipe and use it for engine monitoring. Say what you want, rant on... your not going to get it here.
Somewhere on Freds page, TDImeister has done some calculations. Search it out and see if its what you seek.
Or go post turbine, mentally subtract 200 or 300 degrees (your choice) from you gauge measurements and hope for the best.
Ranting?Nope. I'm trying to have a meaningful discussion on a discussion board about a topic that, evidently, people have strong opinions on, but have little to no information on which to base those opinions. And no, I won't just"hope for the best." If it turns out I'm wrong, I'll relocate the probe pre turbine and accept the risk.
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Larry,
Engineering is indeed a compromise, and a good engineer makes a good compromise... most things are in fact not black and white and grey areas do exist. This might well be one, but..
You could restrict yorself to 1600F or source a better probe.
This position thing would be much less important in an aircraft, as that's pretty much a steady state situation, with reference EGTs for diffeernt flight phases (e.g. max Take-off, climb high alt. cruise etc.), but even then I think they might and indeed do risk a proven installation pre-turbine.
It's just a case of getting ther MTBF of the probe another order of magnitude above the MTBO of the engine. The odd rogue probe might come along, but those specified for a given aircraft application would generally be from an approved source, even for light aviation.
In the case of an automobile, the grey area moves a long way towards white, as the outcome is rarely going to be life threatening, and using the true and fast reading egt gauge itself, most remaining darkness can effectively be ruled out. If detonation played a part, as it does with glow-plugs, I'd be more circumspect, but temps themselves that should be under control I'd dismiss unless on a test bench and going for it...
In the vanishingly small likelihood of a probe failure within the working range, one has to accept you are in the lap of the gods.
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According to your info you saw some probes fail at 1700. If you are running a VW diesel then your probe will never see 1700*F pre-turbine (the damage limit to probes that you propose) unless you don't care if your engine melts. I suspect that 1700 is fairly low for probe failure, as most are rated significantly higher than that and most ratings for materials incorporate a safety factor against liability. If a probe fails at 1700 for a gauge that reads 1800 then the manufacturer of the sender would be liable for damages. Most companies try to avoid litigation by incorporating a safety factor.
Andrew, I said and meant 1,600 F, not 1,700 F. The system was cold-junction compensated with an RTD. Safety factors? Liability? I'm reporting facts.
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The opinion in this "discussion" is that post turbine may be a valid measurement.
There is no one here that has taken the time to mount two probes and record the data.
Slave2school offered to get the data for you for 50 bucks.
Pre turbine measurement is proven to be valid and is currently used and endorsed in this application. It has been field tested, and there is no evidence of probe failure in this application.
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jackbombay, I don't know you. But I'm not trying to convince anyone or put people down. I just have a tough time accepting something without solid proof. I'd simply like to see numbers to back up the claims. :mrgreen:
Inaccurate gauges drive me nuts, subtracting a theoretical 200* degrees to determine the turbine inlet temp is not my deal, why not measure the actual parameter you are interested in? It's more work, and there is a minuscule risk of probe failure, we weight those factors differently.
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Oops, yup, 1600. Nice irrelevant nit to pick there. Regardless, everything else I posted stands. 1600 and you're likely in trouble and not from your probe. Are you really not getting it? Or just trying to prolong the attention your getting?
Andrew
Andrew, as I said, 1,600 F with negligible vibration. VW diesels vibrate, alot, which can fatigue certain metals at elevated temperatures, though as you say max temps are lower than what I was working with. You know much more about diesels than I do. I'm learning, and Ilike to base decisions on facts, not anecdotal information. Sorry.
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Larry,
Don't be sorry, this has proved an inspirational opportunity to moot pros and cons on an abstract subject that doesn't really affect any of us much... and keep away from more meaningful stuff
just so happens I'm ordeing an EGT setup now, in the UKk, and have given the specs to my man and he's sourcing what he thinks is the best he can get for my application: I'll either say Yes or say No when I hear his proposals, but none of them sound expensive c.f. the Aircraft Spruce or other US offerings..
I've quoted 1650F for a pre-turbine placement, gauges to suit, length of wiring extended to suit - and they supply to light aircraft owners mainly.
Hopeful, and having manifold off, will drill where I think fit M8 thread and pray.... :D
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Larry,
Don't be sorry, this has proved an inspirational opportunity to moot pros and cons on an abstract subject that doesn't really affect any of us much... and keep away from more meaningful stuff
just so happens I'm ordeing an EGT setup now, in the UKk, and have given the specs to my man and he's sourcing what he thinks is the best he can get for my application: I'll either say Yes or say No when I hear his proposals, but none of them sound expensive c.f. the Aircraft Spruce or other US offerings..
I've quoted 1650F for a pre-turbine placement, gauges to suit, length of wiring extended to suit - and they supply to light aircraft owners mainly.
Hopeful, and having manifold off, will drill where I think fit M8 thread and pray.... :D
Thanks, and good luck with your EGT installation.
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No, unfort. aircraft gauges seem to read down to about 400C and thats it, as I say, they're more interested in steady state soak temps than much else. As long as the top end goes up high enough, I'll be happy... some even only have a 4 to 9 range, 400 to 900C
Buit bet they're pretty accurate within that range 8)
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The westach gauge I have reads from 100F-1900F
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Thats handy to know when my source gets back to me... 100~1900, nice wide range that.
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This is exactly the one I got.
http://aircraftspruce.com/catalog/inpages/westegt2.php
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Thats handy to know when my source gets back to me... 100~1900, nice wide range that.
I have a Westach combo EGT/boost gauge that reads from 100 to 1500 F.
http://www.genosgarage.com/prodinfo.asp?number=WM-CG-8
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jackbombay, I don't know you. But I'm not trying to convince anyone or put people down. I just have a tough time accepting something without solid proof. I'd simply like to see numbers to back up the claims. :mrgreen:
Inaccurate gauges drive me nuts, subtracting a theoretical 200* degrees to determine the turbine inlet temp is not my deal, why not measure the actual parameter you are interested in? It's more work, and there is a minuscule risk of probe failure, we weight those factors differently.
These EGTs take away some of the guesswork. Green good. Red bad.
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607VWR
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607TR
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You are right. No one has mounted two thermocouples on their engine and recorded these measurements. I doubt anyone ever will, except Slave2School. He clearly offered to do it for fifty bucks. So there is a valide offer to produce the data you desire.
I might just take him up on that! :lol:
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These EGTs take away some of the guesswork. Green good. Red bad.
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607VWR
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607TR
So... they shifted the "yellow" zone back some. That's not going to make your sensor react any more quickly, and if you sustained right at the edge of the yellow in the post-turbine setup (~900F) you would be well into the yellow range of the preturbine setup (~1100F), if it's a straight-shot 200F drop across the turbine.
You said you're doing some calculations; what data are you using in these calculations? Turbo efficiencies, ratios, sizes, engine RPMs, even fuel type used? Boost pressure? Intercooled or non-intercooled; there's a whole lotta stuff that goes into determining EGTs, and a whole lot more that determines how much temperature drop you get across any given turbine.
Personally, I'd rather not "guess" anything at all. If I had the money, I would be monitoring each individual cylinder's output. And each individual cylinder's input, too, black-box style. I am sorely tempted to find a temperature guage that would let me monitor input temps... if only because that would be a cool way to prove some intake cooling mods I'd like to try.
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I thought about getting this just so it could be done easily (each cylinder) http://aircraftspruce.com/catalog/inpages/aerospace_logic.php but the need to eat out weighs the novelty.
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These EGTs take away some of the guesswork. Green good. Red bad.
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607VWR
http://www.genosgarage.com/prodinfo.asp?number=ISS-R3607TR
So... they shifted the "yellow" zone back some. That's not going to make your sensor react any more quickly, and if you sustained right at the edge of the yellow in the post-turbine setup (~900F) you would be well into the yellow range of the preturbine setup (~1100F), if it's a straight-shot 200F drop across the turbine.
You said you're doing some calculations; what data are you using in these calculations? Turbo efficiencies, ratios, sizes, engine RPMs, even fuel type used? Boost pressure? Intercooled or non-intercooled; there's a whole lotta stuff that goes into determining EGTs, and a whole lot more that determines how much temperature drop you get across any given turbine.
Personally, I'd rather not "guess" anything at all. If I had the money, I would be monitoring each individual cylinder's output. And each individual cylinder's input, too, black-box style. I am sorely tempted to find a temperature guage that would let me monitor input temps... if only because that would be a cool way to prove some intake cooling mods I'd like to try.
Turbine delta T depends on turbine inlet temp, pressure ratio across the turbine, turbine efficiency, and the ratio of specific heats, which I am assuming is air (k=1.4). Mass flow into the turbine is what flowed into the compressor and engine, plus fuel. The air portion can be gotten from a turbo map. Engine air demand (flow rate) scales with rpm and displacement. Compressor power demand scales with boost pressure ratio, flow rate, and compressor efficiency. Intercooler efficiency, depending on the intercooler, is a published number. No, I haven't measured IC delta Ts. Again, all this is rough. I need to double check things and, ideally, verify the results with some real data.