Best Location For Pyro

[Bertram65]

I've asked several times over several years what the post turbo numbers where. I've NEVER gotton a good or same answer twice. Anyone got any post turbo numbers? That ADDING a few hundered degrees(is that two hundered or three hundered or?) dosen't sound wise pulling heavy weight in hard pull conditions. Just my thoughts on a post turbo install.

If you call Cummins they will tell you 900 degrees post turbo, this is where Cummins reconmends putting it and where they put it on engines that come with EGT gauges.

 

[DPKetchum]

Whats the cool down temp.

 

[JohnCooper]

Whats the cool down temp.

The number I have heard is 200deg (post turbo)

 

[Highfinance97]

The number I have heard is 200deg

300 Degrees pre turbo if you wait till it gets to 200 you'll prolly be waiting a while :-laf



Michael

 

[cojhl2]

It is my and other professional's opinion that egt is not the criteria to use for engine shutdown.



The gas temp may be cool to say 300 but the internal engine parts are still very hot after a hard pull. With the engine defuled there is no fire to heat the ex gas so it is hot only becasue of heat transfer from hot engine parts.



It all depends on how hard you were working the engine. We always let the engine idle for 5 mins or so regardless of egt readout. We dont even look at it.



If the engine has been merely poking down the road then shutdown is no brainer,, turn it off.

 

[Cory]

I am wondering what DODGE would say if they saw a hole drilled in manifold pre-turbo? I drilled mine and am curious if they would VOID warranty for something like that? Say the turbo goofs up and they wont replace it because they see you've drilled a hole in the manifold and the tiniest piece of shaving destroyed the turbo.

 

[DPKetchum]

I'm sure if it happened right after install its a no brainer. If any one has killed a turbo or ruined a manifold installing one they never have posted it. A few have had questions on failed injectors etc. because of the pyro. I've said this before. Until the 3rd generations came out I never read about anyone installing a pyro POST turbo.

 

[dieselcruiserhead]

I've run pre and post turbo, pre is much better and more accurate...

 

[Radshooter]

I am wondering what DODGE would say if they saw a hole drilled in manifold pre-turbo? I drilled mine and am curious if they would VOID warranty for something like that?

I had mine installed by a Dodge dealer in Idaho. No problems as far as they were concerned.

 

[Bertram65]

I've run pre and post turbo, pre is much better and more accurate...

You should tell Cummins so they can stop giving out bad information and putting the pyros post turbo :-laf . How can you say it is more accurate? more accurate of what? The gauge is just as accurate, it is just reading the temp from a different location.

 

[DPKetchum]

It is a more ACCURATE READING. Its not affected as much by wind/mositure and other cooling affects of metal obsorption. Kinda like a auto trans temp sender in the pan. One placed in the HOT line tells you the REAL trans fliud temp,not after any cooling has taken place. I as soon NOT have a pyro if not in the manifold near the HOTTEST running cylinder. Wheres your coolant temp gauge reading from?A heater hose or down low in the radiator. :-{}

 

[Bertram65]

It is a more ACCURATE READING. Its not affected as much by wind/mositure and other cooling affects of metal obsorption. Kinda like a auto trans temp sender in the pan. One placed in the HOT line tells you the REAL trans fliud temp,not after any cooling has taken place. I as soon NOT have a pyro if not in the manifold near the HOTTEST running cylinder. Wheres your coolant temp gauge reading from?A heater hose or down low in the radiator. :-{}

The two other systems you are referencing are closed loops unlike the exhaust.

I disagree with you on the accuracy issue, pre turbo is not more accurate, it is higher as it is closer to the source of heat but that does not effect it's accuracy, I have also never seen the running EGT temps effected by ambient temp, and I have driven in temps from -10 to 100, the only effect the ambient temp has is how long it takes the turbo to cool down, which you cannot read at all pre turbo. :-laf

 

[DPKetchum]

If ambient temp affects turbo cooldown you don't think heat absortion by the lenght of pipe before its gets to the pyro has a affect? I do. I agree the cooling system is closed loop but REAL high performance autos also run coolant temp gauges with senders fronT,middle and rear with a fairly large differance in temp readings. I'd rather have a unit reading direct combustion temp then in the manifiold much less way downstream in a down pipe.

 

[Bertram65]

If ambient temp affects turbo cooldown you don't think heat absortion by the lenght of pipe before its gets to the pyro has a affect? I do. I agree the cooling system is closed loop but REAL high performance autos also run coolant temp gauges with senders fronT,middle and rear with a fairly large differance in temp readings. I'd rather have a unit reading direct combustion temp then in the manifiold much less way downstream in a down pipe.

Cooldown is the only temp I have seen significantly effected by ambient temp.

This is kind of interesting all kinds of data for the CRD 425hp marine 5. 9l, it even lists the max exhaust temp for pre and post turbo, http://www.gce.cummins.com/mce/mce_QSB/assets/Fr91632.pdf

matches up pretty good to the 300 degree difference people always reference.

 

[Bertram65]

Not sure the link works, here is the data.



Exhaust Gas Temperature Turbine Out... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..... °C [°F] 494 [920]

Manifold ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... °C [°F] 684 [1263]

 

[NIsaacs]

The link worked for me, jeeze, did ya see the boost numbers?





"NICK"

 

[cojhl2]

The difference in gas temp pre vs post comes not from the difference in distance from the engine. The temp difference is becasue the turbo has extracted energy from the exhaust gas to compress the incoming stream.



The function of the turbo is to expand exhaust gas, therefore lowering the temp (PV/T).



Ambient temp has a negligible effect on the dropdown in temp accross the turbo.



So long as you know the rule it makes no diff if the pyro is pre or post. You just gotta know the numbers.



Racing engines are run to the absolute max and therefore may require multiple measurements. We don't or shouldn't run these engines to the absolute limit.



The reason we measure the coolant at the top of the engine is becasue if the water is not circulating you gotta know it. If you could be guaranteed the water would circulate then I guess one could measure the temp at the return to the engine.



Also who is to say where the hottest exhaust is in the manifold. a slight diffenence i injection volume would change that more than a few deg.

 

[JScans]

i have a 04. 5 600 and i put it after the turbo. i have the six gun with intercooler never seen my egt's over 800 degrees. With out the six gun or intercooler i have seen it at about 900.

when i get a new manifold i will put the probe in it for sure. ( i have heard of the probe melting off before the turbo and really messin it up, anyone here of that before? )

 

[cerberusiam]

 ( i have heard of the probe melting off before the turbo and really messin it up, anyone here of that before? )

Every time I hear this I LMAO! :-laf :-laf



I submit the engine has BIGGER problems than a dinged turbo if you melt the tip off an EGT probe. I have still not found anybody that has actually SEEN this happen. Just lots of "I heard about this guy that... . ".

Also who is to say where the hottest exhaust is in the manifold. a slight diffenence i injection volume would change that more than a few deg.

Injector problems aside, the back 3 cylinders run the hottest with #6 being the hottest. This is due the distance from the water pump, the position of the cylinders in the engine compartment, and the block design puts restrictions in the circulation around #6 cylinder. Ever wonder why the temp sensor is on the back of the head? Injector failures aside, #6 is almost always the first cylinder to fail in an extreme situation.



The reasons for putting the probe pre-turbo are the same for putting the trans temp sensor in the output line, to read the max temp without the other factors interfering. The 300 degree difference is an average and can be effected by fueling, turbo type and design, and the distance of probe. The differences are not linear as the temp goes up, and, can easily be 600 to 700 degrees under extreme conditions while taking up to 60 seconds or more to register post-turbo. The 300 degrees works only in normal conditions but toss it if you are adding boxes, fuel, etc, which is why we are adding EGT gauges anyway so why take a chance.

 

[cojhl2]

but toss it if you are adding boxes, fuel, etc, which is why we are adding EGT gauges anyway so why take a chance

Point well taken. I look at things only from a work vehicle standpoint with little or no intent to get extreme max out of the engine.



However those of us who dont soup up our engines still use guages to determine how hard we can work it. A pyro egt guage is a direct link to power demand on the engine.