quick garrett turbo question... opinions

[Tapage]

I was testing my Tencha last sat .. and noew with more fuel I can climb my EGT up to 650ºF fast .. maybe 2 or 3 shift .. but unless I'm in up in the 2+ rpm range .. they keep raising slow up to 1000ºF ..

In the moment that I raise my foot from the skinny pedal .. the EGT goes down fast ..

 

[BillyGHusk]

Hello,
I limit my EGTs to 1100F post turbo, and only for transients(few seconds), i

Hey,
average drop across a average turbo was 250F.
eric

So in less I am missing something....which is possible and some might even say likely.....your pre EGT's are close to 1350. What is considered the red zone for temps? I thought keeping them under 1200 was advisable?

Tim

 

[Otterav]

So in less I am missing something....which is possible and some might even say likely.....your pre EGT's are close to 1350. What is considered the red zone for temps? I thought keeping them under 1200 was advisable?

Tim

Tim,
Thats most likely correct, I only allow 1100F for seconds, not a prolonged period. I have been running my 2 1/2 tom military truck with a turbo at 1200F for almost 20 years and it is not showing any ill effects. Set your own limits and determine the length of time at those temps. I personally feel a short run at 1100F for a few seconds most likely isn't much different than a 4 minute run at 1000F.
Hola
eric

 

[Dougal]

The Isspro that I have on all my trucks is pretty quick in responding. It certainly doesn't keep increasing after the skinny pedal is lifted.

What size probe did that one come with?
My VDO came with a 6mm probe, that was very laggy. I'm now using a 3mm probe which reacts much faster but the lag is still noticable.

Expecting 250F drop across a turbo pushing 18psi is pretty funny. I know people with 15psi boost who've measured 200C, that's almost 400F.

 

[cruiser_guy]

What size probe did that one come with?
My VDO came with a 6mm probe, that was very laggy. I'm now using a 3mm probe which reacts much faster but the lag is still noticable.

Expecting 250F drop across a turbo pushing 18psi is pretty funny. I know people with 15psi boost who've measured 200C, that's almost 400F.

The Isspro probe is quite small at the tip and then widens out to maybe 4-5mm.

I'll agree that the higher the boost the more the charge air temps increase and the higher the psi loss across the turbo as the exhaust goes out the higher the temp loss as well, that's basic gas laws in physics. That's a big reason why I installed the pyrometer pre-turbo, no guessing just hard facts!

 

[Otterav]

What size probe did that one come with?
My VDO came with a 6mm probe, that was very laggy. I'm now using a 3mm probe which reacts much faster but the lag is still noticable.

Expecting 250F drop across a turbo pushing 18psi is pretty funny. I know people with 15psi boost who've measured 200C, that's almost 400F.

Again,
I would suggest that you call Banks Engineering and ask them yourself. You seem to be an expert with absolutely 0.00% background that exists anywhere except in your own mind. Corky Bell, Banks Engineering both well respected and acknowledged experts in the their fields, are just a few of the sources you so readily dismiss as wrong. Your "theories" are refuted by multiple sources, I would implore you to return to reality and join the rest of the normal world. Again the "15psi boost people who've measured 200C" folks most likely used your flawed theories and wrong sized their turbos and are operating outside their efficiency envelope. I find no small amount of humor, that you quote a 400F drop across the turbo by "people" you know, and Banks quotes 250F drop, I would guess thats the difference between a properly designed system and one that is designed with VOODOO engineering. I will offer a suggestion, buy a Landcruiser, drive it some, work on it a little, and come back here with a little real world experience. Until then your VOODOO engineering principals are suspect.
Hola
eric
P.S. Mods, this is not a personal attack, this is a fundamental disagreement in principals of turbocharging theory.

BTW, when I received my ISSPRO pyrometer, I checked it for operation prior to install using a propane(gasp the "P" word) plumbing torch, the meter registered almost immediately and when removed from the flame stopped rising immediately and dropped as quickly.

 

[brownbear]

P.S. Mods, this is not a personal attack, this is a fundamental disagreement in principals of turbocharging theory.

welcome to public forums. You're always going to see opinions that are not true or flawed being touted as fact. Simply ignore. Use the features of the forum.

 

[Dougal]

Again,
I would suggest that you call Banks Engineering and ask them yourself. You seem to be an expert with absolutely 0.00% background that exists anywhere except in your own mind. Corky Bell, Banks Engineering both well respected and acknowledged experts in the their fields, are just a few of the sources you so readily dismiss as wrong. Your "theories" are refuted by multiple sources, I would implore you to return to reality and join the rest of the normal world. Again the "15psi boost people who've measured 200C" folks most likely used your flawed theories and wrong sized their turbos and are operating outside their efficiency envelope. I find no small amount of humor, that you quote a 400F drop across the turbo by "people" you know, and Banks quotes 250F drop, I would guess thats the difference between a properly designed system and one that is designed with VOODOO engineering. I will offer a suggestion, buy a Landcruiser, drive it some, work on it a little, and come back here with a little real world experience. Until then your VOODOO engineering principals are suspect.
Hola
eric
P.S. Mods, this is not a personal attack, this is a fundamental disagreement in principals of turbocharging theory.

BTW, when I received my ISSPRO pyrometer, I checked it for operation prior to install using a propane(gasp the "P" word) plumbing torch, the meter registered almost immediately and when removed from the flame stopped rising immediately and dropped as quickly.

Eric I'm afraid there is quite a difference between the opinions of Mr Banks and Mr Bell and your interpretation. Because someone disagrees with you, doesn't mean they disagree with them.
Mr Bell's book for example does not mention diesel engines at all.

For example.
The temperature and pressure drop across a turbine varies with boost, backpressure and EGT's. Picking a single figure (like 250F) and applying it to vastly different operating conditions is rather silly.

Another example.
Your pyro probe reacts much slower to changing gas temp than it does when you stick it straight into a propane flame.
It reacts even slower still when you place it after the turbo, roughly two feet after your exhaust ports and where it is subject to the cooling effect of the exhaust manifold, the turbo housing, the turbine wheel and the dump pipe.

Basically a probe placed in the dump pipe requires a fudge factor put in place to guess what the real reading is. If you guess wrong then you are drastically shortening the life of your engine.

It is the temp of the gas leaving the exhaust ports that is critical. Why not measure that?

 

[crushers]

okay, bring me up to speed...
this is what i have gathered from reading this thread.
you installed a turbo
you reused most of your orignal exhaust system
you do not have a pyro installed yet
you have not cranked up your fuel yet
you are experiencing over heating on long hills

is this correct?

first, the exhaust temps do not corespond to water temps. you can be running at 800F and hit the red water temp. you can be running cool water temps and hit 1300F exhaust temp. the two are NOT related. the water temp rises slowly, the pyro can climb faster than your tach.

you are not experiencing any of what that setup can accomplish SAFELY. you NEED a pyro and a long hill. run the hill stock settings and see what the pyro reads, crank up the fuel 1/4 turn at a time and rerun the hill. once you are maxed at 1200F then that is the max you want the fuel.

you can safely run a 3B at 14 psi which will change the fuel settintg availability.

if you are running AC then you might have to test the same hill that causes the engien to over heat with the AC turned off. check the rad for blockage. the rad size you have is the same as the one for the 12HT so the actual rad size is not the issue BUT if you can locate an aluminum 4 core then that might help.

for your driving habits that size turbo is probably excellent choice.

i STRONGLY recommend you get a pyro installed ASAP since you really have no idea what is happening at the combustion chamber.

<read sig line>

 

[cruiser_guy]

I'm with Wayne 100%. I would also strongly suggest you check and see if you have a 3 core or 4 core rad. Toyota calls for a 4 core rad on all A/C equipped 'Cruisers but my '82 BJ60 came factory with a 3 core. I had to change to a 4 core when I installed A/C.

ANY changes or adjustments to the turbo REQUIRE a pyrometer or you're just guessing and you could be dangerously wrong.

 

[crushers]

oh, and going to a larger exhaust will not change the cooling system of the engine it will however purge the head of hot exhaust gasses quicker which will lead to cooler EGTs and a faster spooling turbo...

your busted exhaust is proof positive, no back pressure and quicker response... the 'feeling' of more power... a larger exhaust does NOT increase the hp, it purges exhaust gasses...

 

[Otterav]

Eric I'm afraid there is quite a difference between the opinions of Mr Banks and Mr Bell and your interpretation. Because someone disagrees with you, doesn't mean they disagree with them.
Mr Bell's book for example does not mention diesel engines at all.

Again you post your "opinion" without any supporting data, mere opinion. BTW when you imply that my numbers are suspect, even when observed/verified by 2 separate mud members. I will ask you again what is/are the material differences between these types of internal combustion engines? What is combustion temperatures of each engine type, how much temp is lost in each typical exhaust manifold?

For example.
The temperature and pressure drop across a turbine varies with boost, backpressure and EGT's. Picking a single figure (like 250F) and applying it to vastly different operating conditions is rather silly.

Rather silly, I stated a general number, as provided by Banks Engineering, now can you provide a specific number across a specific turbo. A turbocharger extracts energy from the exhaust to perform work, duh! Of course the downstream flow will have less energy(heat), the thousand dollar question is how much?

Another example.
Your pyro probe reacts much slower to changing gas temp than it does when you stick it straight into a propane flame.
It reacts even slower still when you place it after the turbo, roughly two feet after your exhaust ports and where it is subject to the cooling effect of the exhaust manifold, the turbo housing, the turbine wheel and the dump pipe.

Funny, I don't remember saying I placed the probe directly into the flame. I placed the flame under the probe and slowly raised the flame towards the probe until the probe registered 1500F, and when I removed the flame the temp immediately started dropping.

Basically a probe placed in the dump pipe requires a fudge factor put in place to guess what the real reading is. If you guess wrong then you are drastically shortening the life of your engine.

The location of the pyro probe anywhere other than the exhaust port is fudge by definition. There are lots of things that will shorten the life of the engine, adding a turbo and raising the BMEP, by definition decreases the engine life.

It is the temp of the gas leaving the exhaust ports that is critical. Why not measure that?

See above.

 

[Dougal]

Rather silly, I stated a general number, as provided by Banks Engineering, now can you provide a specific number across a specific turbo. A turbocharger extracts energy from the exhaust to perform work, duh! Of course the downstream flow will have less energy(heat), the thousand dollar question is how much?

Why are you trying to use a number from Banks? They don't fit supra turbochargers to 3B's so their numbers do not apply.

Here's an acceleration scenario for you.
15psi boost, 30psi exhaust backpressure (measured result from hard acceleration).
EGT pre-turbo 730 deg C.
Turbine efficiency 65%
Calculated temp drop across turbine = 243 deg celcius
EGT post-turbo = approx 480 deg celcius.
470 deg F drop

Steady high load scenario.
15psi boost, 15psi backpressure (measured results)
EGT preturbo 730 deg C.
Calculated temp drop = 144 deg C.
EGT post-turbo = approx 580 deg C.
290 deg F drop

Cruise scenario.
10psi boost, 15psi backpressure (measured results)
EGT preturbo = 450 deg C
Calculated temp drop = 105 deg C
EGT post turbo = approx 345 deg C
220 deg F drop

 

[Dougal]

Now lets run the turbine formulae backwards to see what we get.

Conditions.
Boost = 18psi. (124 kPa)
Drive ratio = 1.5
Turbine drive pressure = 27psi (186 kPa)
Turbine outlet temp = 1100F (590C)
Turbine efficiency 65%

Turbine Temp drop = 251C (483F)

Exhaust temps into turbine (EGT) = 840C (1545F)

Well that explains how you can spool a large turbo faster than the petrol engine it was attached to. Your EGT's are higher than the average petrol engine and well beyond diesel danger limits. Especially on an indirect injection engine.

Problem is, you back the fuel down to safe levels and you won't be able to acheive 15psi boost until around 3000rpm.
This kids, is why I consider the supra turbo to not be a suitable match for the 3B.

 

[Otterav]

Now lets run the turbine formulae backwards to see what we get.

Conditions.
Boost = 18psi. (124 kPa)
Drive ratio = 1.5
Turbine drive pressure = 27psi (186 kPa)
Turbine outlet temp = 1100F (590C)
Turbine efficiency 65%

Turbine Temp drop = 251C (483F)

Exhaust temps into turbine (EGT) = 840C (1545F)

Well that explains how you can spool a large turbo faster than the petrol engine it was attached to. Your EGT's are higher than the average petrol engine and well beyond diesel danger limits. Especially on an indirect injection engine.

Problem is, you back the fuel down to safe levels and you won't be able to acheive 15psi boost until around 3000rpm.
This kids, is why I consider the supra turbo to not be a suitable match for the 3B.

Ahhaaa yes,
Again you formulate from what source? Perhaps some quotes would support your position. I was reading Diesel engine theory today and I completely missed these formulas, you pullin stuff outta where again? I guess my 30 year old(w 300KM at install) abused(prior to me) Canadian cruiser 3B just hasn't read your posts. I guess the 15-20K miles I have driven since the turbo install weren't on your "danger, will robinson" schedule. The reason the CT-26 works so well on the 3B is that 3B is about 10% larger in volume. Even if your equations are accurate(which I seriously doubt), you will note that I stated for only a few seconds, but I guess you just cannot stand being wrong, seems like you spend a lot of time there, I would think you would get used to it.
eric
P.S. I bet it just makes you crazy, that you cannot figger out why my stuff works and you still do not have a Landcruiser!

 

[Dougal]

Ahhaaa yes,
Again you formulate from what source? Perhaps some quotes would support your position. I was reading Diesel engine theory today and I completely missed these formulas, you pullin stuff outta where again? I guess my 30 year old(w 300KM at install) abused(prior to me) Canadian cruiser 3B just hasn't read your posts. I guess the 15-20K miles I have driven since the turbo install weren't on your "danger, will robinson" schedule. The reason the CT-26 works so well on the 3B is that 3B is about 10% larger in volume. Even if your equations are accurate(which I seriously doubt), you will note that I stated for only a few seconds, but I guess you just cannot stand being wrong, seems like you spend a lot of time there, I would think you would get used to it.
eric
P.S. I bet it just makes you crazy, that you cannot figger out why my stuff works and you still do not have a Landcruiser!

You'll find the relevant equations in any good thermodynamics text book. Turbine (brayton) cycle.

The 3B may have 10% more capacity than a supra engine, but it has only 50% of the rev range.
Which gives you 55% of the airflow.

 

[gerg]

Keep it up guys... this is some kewl s***e!

 

[BillyGHusk]

if I remember right this is the 2nd, 3rd, heck maybe 4th time this has been going on.....Cool for a while but from my point of view nothing is ever settled.

I think they are more then likely both right on somethings and both wrong on somethings. God forbid we ever admit anything like that.

 

[Dougal]

Cool for a while but from my point of view nothing is ever settled.

True the background tune has never changed and probably never will, but the recent revelation of EGT levels has filled in a lot of gaps.

 

[BreckenridgeCruiser]

Guys, As an outsider (not involved in this discussion) who is following this thread to see how this turbo affects the performance and reliability of this case, I have one conclusion.

It seems that there are way too many variants of systems, environments, load, weather, terrain, etc. here. The one conclusion I have come to after reading a ton of threads on turbo, pyro, etc. is this: tune your truck for your needs. Start conseravatively and adjust to your risk tolerance. I am more concerned with relaibility so I may tune my fuel to keep my pyro below 1100. Some may feel that pushing 20 psi and higher egt are fine.

Summary: look at your application and understand that with so many variables, you will need to find your own balance.

my .02

Question for Crushers. If a higher diameter exhaust will allow faster spool, wouldn't this account for the 'feeling' of more power?