Engine/Transmission (1998.5 - 2002) ATTN: Gary - KJ6Q (RE: EGT's and defective thermocouple)

[jlccc]

I sent this is a PM to you, but with the server problems, I don't think you received it. I decided that this may have application to the general membership so I am posting the contents of the original PM as a topic.



---begin posting---

Gary-KJ6Q



I have read with great interest how your ETH seems to run very cool (<1200F always) when towing, even when running at the 5X5 setting on your Edge Comp. I'm currently searching for ways to keep the EGT's in check on my own ETH when towing hard, uphill--and I'm only towing 5-6K lbs.



While considering your apparent good fortune, the following thought has been nagging at me and I wanted to share it with you in hopes that I might prevent you from seriously damaging your rig.



In a nutshell, I think your thermocouple is lying to you. Sometimes a thermocouple will reach a "maximum" value and then stop producing a proportional voltage, regardless of what the actual temperature is. Outside of a complete failure to produce voltage, this is the most common symptom of thermocouple failure.



You can easily check your thermocouple by removing it and heating it with a simple propane torch while it is hooked up to a digital voltmeter (or the pyro gauge itself). Be careful not to get it so hot that you ruin it (assuming nothing is wrong with it to begin with) but heat it enough to verify whether or not it "stops" at a certain voltage value and won't climb any higher, regardless of how much extra heat you apply.



Good luck and I hope you find your thermocouple is in working condition.

 

[Whitmore]

jlccc is correct

before you melt a piston do it , I seriously dought that you can heat a thermocouple beyond the point of no return with a propanr torch but I may be wrong here, some months back in the TDR mag thet did a test on this very issue and the article was full of good info,



I personally do not think that you can keep your temps below 1200 with your bombs Gary. but I have been wrong before.



I find it of great interest that jlccc has been concerened over your truck, it bothered him to the point of bringing it to your attention ... ... ... cuddos to jlccc

 

[Brandon]

eth with a comp at our ca elevation can make 1400 empty at wot, just ask danelle... ... ...

 

[rubberneck]

Hx35 with comp box and dd3's set on nuke, and I was pumping 1600+ at the end of the quarter mile. Even with stock injectors, 1400+ was no trick. Best for towing is the larger injector and leave the comp on level 1 or off. The wire tap boxes all add fuel longer during the injection cycle which leads to higher egt's. Oh yeah and for towing, the tighter the turbo the better. Not the other way around as some may try to get you to believe around here.

 

[jlccc]

Originally posted by rubberneck

Oh yeah and for towing, the tighter the turbo the better. Not the other way around as some may try to get you to believe around here.

Says who? Please elaborate. I just spoke with Al at Piers Diesel Research not three days ago and we discussed a 14cm or 16cm turbine housing to replace my 12cm.



I'm not looking for more boost, just less restriction in my exhaust housing. The "looser" turbo WILL help with EGT's by reducing drive pressure. The 12cm turbine housing chokes at around 30 psi (on the exhaust side, I'm not talking about the compressor side). With the larger turbine, I may have a bit more lag at the low end but I will have a freer flowing turbine at the high end, allowing exhaust gases to escape the turbine easier and yet, still retain the same amount of boost on the compressor side.

 

[jlccc]

Re: jlccc is correct

Originally posted by Whitmore

I seriously dought that you can heat a thermocouple beyond the point of no return with a propane torch

Maybe not with a Type K thermocouple, but I have done it with a Type J before.

 

[Koa Man]

Regarding a "tighter" turbo, I recently changed to a HX40/16 and I tow daily. There is very little difference in initial takeoff for me, but I always slowly roll on the power, not punch it. EGTs on the top end have been lowered significantly and are extremely controllable. Little more black smoke initially, but it clears immediately once boost hits about 10. I went from stock to PDR HX35/14 to the HX40. The PDR HX35 is a great turbo and would have been all I needed except pushing my flatbed headboard (5 ft. high) against the air at speed is killing me. I lost 5 mpg in the switch from stock bed to the flatbed I have now. Truck cannot do more than 80 mph on the level. I could previously do 80 mph @ 1300* up a 6% grade with the stock turbo and stock bed (not towing). Thinking of putting on an air wing of some sort. In desperate need of aerodynamic help.

 

[Shovelhead]

Koa Man,

Check the classifieds ad #3551

There's a "slightly used" Turbowing for sale.



disclaimer: not affiliated with the seller, or Turbowing.

 

[Koa Man]

Thanks Shovelhead, but I think I need a bigger one. Something like RHARVEY has on his truck for pulling his 5th wheel. I see those for sale in the Camper's World catalog. My headboard extends about 2 feet above the cab and is 94 inches wide.

 

[rubberneck]

Originally posted by jlccc





Says who? Please elaborate. I just spoke with Al at Piers Diesel Research not three days ago and we discussed a 14cm or 16cm turbine housing to replace my 12cm.



I'm not looking for more boost, just less restriction in my exhaust housing. The "looser" turbo WILL help with EGT's by reducing drive pressure. The 12cm turbine housing chokes at around 30 psi (on the exhaust side, I'm not talking about the compressor side). With the larger turbine, I may have a bit more lag at the low end but I will have a freer flowing turbine at the high end, allowing exhaust gases to escape the turbine easier and yet, still retain the same amount of boost on the compressor side.

I have seen this on my own truck. As far as who i have confirmed this theory with, they will chime in here if they want to, but i am not alone in finding this. Now realize something here, i am not talking about a small change like going to a 14 or 16 cm housing. That is not near enough to controll the egts some of us see when racing or hotrodding. i am talking about going to the larger chargers. All im going to say is take the same truck same mods same load (please make it a big one, not just the family boat) and tow up a big long hill, do it with both say a hx35 and maybe a B1 or an hx40 or hybrid h2e, post what happens. I have done this have you?? I know what happens, I dont need any opinions on the matter, I have seen the data. All im going to say is i keep both chargers. If im going to be doing a lot of heavy towing, i run the 35, when i want to hotrod and make huge TOP End power, i run my big charger.

 

[jlccc]

Originally posted by rubberneck

Now realize something here, i am not talking about a small change like going to a 14 or 16 cm housing. That is not near enough to controll the egts some of us see when racing or hotrodding.

I should have made it clear that my application is towing, not racing or hotrodding. (And so is Gary - KJ6Q's if I'm not mistaken. )



In your original post, when you say a "tighter turbo" you are not being clear about whether you are referring to the compressor side or the turbine side. I am only referring to the turbine side. I'm looking to make the same boost, with less exhaust restriction to help me control EGT's when towing. A LARGER, LESS RESTRICTIVE turbine housing like a 14cm or 16cm will help do this (assuming you have enough fuel to drive the larger housing, which I do with 275's and an EZ).

 

[Bob Wagner]

anyone have a non wastegated 14cm housing available for testing? I would lve to compare the lag and egt difference while towing a 5er





This is sounding interesting

 

[jlccc]

Originally posted by Bob Wagner

anyone have a non wastegated 14cm housing available for testing? I would lve to compare the lag and egt difference while towing a 5er

They can be had for about $150 new. Here is a link to an eBay seller here in SLC. They also sell 16cm housing for about the same money.



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1850574724

 

[Brandon]

Jl will you please read what rubberneck is saying... ... ... ... ... ... ... ...



we have towed with them all, so far we cannot be a 35.



WE HAVE TRIED THEM ALL. shoot the only trailering my truck does with the twins is when it is ON the trailer

 

[jlccc]

Originally posted by Brandon

Jl will you please read what rubberneck is saying... ... ... ... ... ... ... ...

I'm trying to, but I think we are talking past each other. He seems fixated on the compressor side, I am focused on the turbine side.

we have towed with them all, so far we cannot be a 35.

You mean you can't 'BEAT' a 35? If so, I agree with you, but, if you have enough fuel, a larger turbine housing, attached to an HX35 compressor, will reduce drive pressure FOR THE SAME AMOUNT OF BOOST, resulting in reduced EGT's. Are you saying this is not true?

 

[Brandon]

yes "beat",



exhaust housings are what we are talking about... ... ... ... .



All the big trubos with fuel dont work trailering at a sane speed "less than wot" all our trailering with a big turbo and lots a fuel has produced high egt's and lower boost while trailering, the only turbo we have not tried on this truck is a pdr40 , mabye we should talk to piers about it, we have gone head to head with the others they have not worked well



bottom line with the big turbos we are always under the turbo while pulling the grades=egts, unless we go to wot but you know as well as i do we cannot pull 12-13k trailer at wot



blair chime in here a little bit

 

[rubberneck]

Look, im not saying the 14 or 16 cm units arent great ones, I have a 14 cm on my first gen truck, works great. And i guess i posted this in the wrong place, it was just that i had just finished reading an older post where a guy was relatively new and was asking if he could tow his 10k 5er with dd3's and a comp box. Everyone got on and said he would need a bigger turbo, blah blah blah. Bigger turbos and housings help on the top end, not the bottom. This we agree on, so my question is what rpms do you tow at??. With 3. 54 and 33 inch tires, at 65 mph, im at 1800 rpm. Now i just got back from 1000miles of towing through all kinds of hills with the larger turbo on the truck. It cost me a gear on the larger hills, and even some of the shorter ones i had to have my eyes glued to the pyrometer. Fact is on the same hill same load, the big turbo put out 12 psi less boost than the 35/12. As compared to empty when i can really put the fuel to it, the bigger turbo way eclipses the 35. You cant make enough drive pressure to turn it to adequate boost levels at normal towing speeds. Its not a fuel issue either, You said you have 275's and an ez, I have way more fuel than that, but i cant use it to spool the turbo, pyro is off the chart by the time the big charger comes to life.

Your point is well taken that i am talking about a whole bigger turbo all the way around, not just a looser turbine housing. HOWEVER, even with the 35 you can overdo it with the exhaust housing. All we need to do is go back a little in time to our 1st gen cousins. they all came with 18 and 21 cm housings. And guess what they get hot when they tow heavy. I put a 14 on the first gen, and heating went away. Im not saying that the 16 is overkill, as many members have had praise for it, and it is the one thing i havent tried on the 01 truck, I might do that next. Now to get the post back on track, Gary if you are out there, i would definitely be suspect if you never see more than 1200 on the pyro with the comp on 5x5, like i said i could easily do that with stock injectors and my box set on kill.



Im not trying to have a pi$$ing contest just trying to share some info that i have learned through expirementing with turbos, injectors, and boxes while towing heavy (GVW 19k to 23k) on long steep hills.

 

[Greg Boardman-RIP]

Originally posted by Brandon

yes "beat",



exhaust housings are what we are talking about... ... ... ... .



All the big trubos with fuel dont work trailering at a sane speed "less than wot" all our trailering with a big turbo and lots a fuel has produced high egt's and lower boost while trailering, the only turbo we have not tried on this truck is a pdr40 , mabye we should talk to piers about it, we have gone head to head with the others they have not worked well



bottom line with the big turbos we are always under the turbo while pulling the grades=egts, unless we go to wot but you know as well as i do we cannot pull 12-13k trailer at wot



blair chime in here a little bit

If I am out of line here let me know? Just wanted to dispute the talk about big turbos not working for towing. I have the PDR HX40-16 on my truck. I sent the wife and two of our friends to Idaho last weekend with the 28 foot stock trailer in tow. I set the comp on level 1x3 and told her to keep it under 1250* on the pyro. On the way up there they got 16 mpg with 5200 lbs in tow. On the way home they got 13 mpg with five horses added to that. Well say 6000 lbs extra. My buddy who went with her has a 99 5 speed and he said that my truck hauls like nothing he has ever driven. In pulling long hills with a load on it the temps stay in the 1050* range. The boost will stay up around 20 psi and that is at the 65 mph rubberneck is talking about. Now just to let you know, I am running 32" tires and 4. 10 gears. @65 I am right around 2100 rpm's. If I really push it, like up to 80, I get even better milage. I have seen 19 mpg calculated. Thats towing 150 miles at 80 mph pulling the trailer to the vet with 6 head. I will admit that the HX40 is a bit of a dog down low. I see drive pressures of 2-6 psi cruising down the road empty. When towing I see and average of 12 psi on flat land. I wish it would stay up around 18 all the time. That would be fun... ... . Greg

 

[rubberneck]

Originally posted by Greg Boardman





If I am out of line here let me know? Just wanted to dispute the talk about big turbos not working for towing. I have the PDR HX40-16 on my truck. I sent the wife and two of our friends to Idaho last weekend with the 28 foot stock trailer in tow. I set the comp on level 1x3 and told her to keep it under 1250* on the pyro. On the way up there they got 16 mpg with 5200 lbs in tow. On the way home they got 13 mpg with five horses added to that. Well say 6000 lbs extra. My buddy who went with her has a 99 5 speed and he said that my truck hauls like nothing he has ever driven. In pulling long hills with a load on it the temps stay in the 1050* range. The boost will stay up around 20 psi and that is at the 65 mph rubberneck is talking about. Now just to let you know, I am running 32" tires and 4. 10 gears. @65 I am right around 2100 rpm's. If I really push it, like up to 80, I get even better milage. I have seen 19 mpg calculated. Thats towing 150 miles at 80 mph pulling the trailer to the vet with 6 head. I will admit that the HX40 is a bit of a dog down low. I see drive pressures of 2-6 psi cruising down the road empty. When towing I see and average of 12 psi on flat land. I wish it would stay up around 18 all the time. That would be fun... ... . Greg

Definitely not out of line greg, just trying to get some info out. Like brandon said the only one not tried has been the pdr40. That may be next. I hate to speak for other members, but I remember in another post a while back. BPINE said that the pdr 40 was "the best of the big turbos" he has towed with. I know he hauls a big trailer,and has tried just about everything.

I have one question, When towing up the hills, i imagine your auto kicks out of overdrive. What rpms/ speeds are you running say up 6-7% grades with that kind of load. I know if I down shift and rev the snot out of it temps come down and boost goes up. The larger charger loves the RPM. However, my point all along has been with the small charger, I could hang in the taller gear longer and keep speeds up, rpm down and temps down longer.

 

[Greg Boardman-RIP]

Originally posted by rubberneck





.

I have one question, When towing up the hills, i imagine your auto kicks out of overdrive. What rpms/ speeds are you running say up 6-7% grades with that kind of load.



I run with the smart controller on most of the time. I have it set at 54 mph for the shift out of od. I have yet to have it downshift into 3rd unless I am plegged by corners and curves. For example I ran a 6% grade coming into the town I live in hauling 18,000 lbs of hay at 70 mph. I can set the cruise now with the big HX. I used to have to downshift because of EGT's when I was running the HY.





I know if I down shift and rev the snot out of it temps come down and boost goes up. The larger charger loves the RPM. However, my point all along has been with the small charger, I could hang in the taller gear longer and keep speeds up, rpm down and temps down longer.

I too downshift when I have to (curves) The boost jumps to 38 psi instantly. I think the main difference is the 4. 10 rear end I have. When I run empty, This thing is a hot rod.....