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My Burb is NOT overheating when towing...It's spring!!!

A

Acesneights1

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well right about now is time for my annual "Help my 6.5TD is overheating while towing but this time around I got it licked. I sold my Dually and took a 93 k3500 6.5TD on trade. The truck is not running,bad starter, possible bad head and the electrical system is fried. The trucks name is "Lucky". Anyway this truck has some weight to it as well as the trailer I had it on and the Burb towed it back from NY up some nice long grades and never really went over 190. I hit 200 once but not for long,...WTF ? Why now ?
This truck is completely unmolested stock save for the Diamond Eye 4inch ex from Leroy.
Now here's my theories...
1)Putting Chips/reflash and turbomasters just makes them run too hot
or
2) I forget who said it but there was one lone voice that told me hollowing out the cat would cause turbulence and cause more backpressure. This time around I did a straight 4 inch system with no cat. Could that have been it all along ? I really pushed the burb to see what it would do. it was in the 70's today and that truck did not get hot AT ALL. The truck towed awesome as well.
 
I would agree with point #1. You add more fuel to an engine and it's gonna get hotter, I don't know if a turbomaster will get an engine hot. I would suspect if anything it causes an engine to run cooler if egt's are cooler in the end. Hollowing out a cat might create turbulence in the exhaust stream but at the same time I would surmise that it will flow out easier since the blockages aren't there anymore.
 
ROFL, BJ...

Kenny, Ed is on point with this line of thinking. Adding fuel is going to make things hotter, but there are a lot more variables than that. Good chips or reflashes do much more than simply dump in more fuel, they alter timing curves, shift points, etc, all of which can make you run cooler.

Next, adding more air makes you run cooler, as it increases the rate of thermal throughput in the engine... up to a point.

When you compress air (turbo) it gets hotter, and putting more heat into the front of the engine is a bad idea (it generates enough on its own). Using an intercooler cools the intake air before it hits the engine,

Secondly, using a wastegated turbo will hold back the heat from escaping (at high boost presures), holding the heat in the heads longer (high EGTs). Restricted exhaust does the same thing, for the same reason. Using a clear, open, mandrel-bent exhaust can help let the hot gasses out, and using a non-wastegated turbo can increase thermal throughput without increasing restriction.

That's the whole point of an ATT - it is more efficient in terms of thermal throughput for the same amount of airflow, therefore it generates less heat in the front end and holds in less heat on the back end.

That being said, the purpose of a Turbomaster is to raise boost and airflow, and a good chip and turbomaster combination works very well.

Not all chips are created equal; the old BD chips would fry an engine when towing. Not all turbomasters are created equal, either.. buying one that has been rigorously designed and tested to get it right is not the same as making one out of spare parts... cheaper isn't always better.

Ask Edzzed - he has had both on the same engine, in the same configuration.
 
I used Heath tune and heath TM and ran hot which is why I am revising the turbulence idea. I mean my previous overheating posts always left everyone wondering why other than things just happen to me that can't be explained....:D
The Dually ran high egts towing and so did my tahoe....So did my old 2000 so what did I do ..right ?? The only variable that ha changed is the complete removal of the soot trap as opposed to gutting it...Coincidence ?
The guy who bought my Dually lives in NY where you can grease the inspection easily. I'm gonna tell him to cut that cat out and run the 4 inch to the DP. He doesnt tow anyway so I doubt he'll ever have my issues.
 
JiFaire said:
. Not all turbomasters are created equal, either.. buying one that has been rigorously designed and tested to get it right is not the same as making one out of spare parts... cheaper isn't always better.
Ask Edzzed - he has had both on the same engine, in the same configuration.
Click to expand...





True enough, one only need look at my sig. Even with the ATT I can still generate some high egt's when towing only. But that could be due to having the HP4 vs. a towing tune.
 
Last edited by a moderator:
well, on my Dually there was that. I asked Bill for a towing tune but I think the request got crossed somewhere cause when he looked up what he did, he said..You wanted more power no ??? he tuned that thing hot. I mean it ran, I mean ran but I could get it hot quick towing.
 
You know I never bought into the hollowed cat causing turbulence but...thinking about this more, when the guy at the ex shop cut the 4 inch into the back of it I'll bet he stuck the pipe into the cat a few inches and then welded it and that could cause backpressure/turbulence...Hmmmmm
 
Outside temps, AC load, and how you load the engine and what RPM all make a difference on the temperature spike before the fan locks in to cool you down or maintain temperature.

Exhaust carries like 66% of the heat out of an engine. Any restriction like a 08 Dmax DPF requires a 25" fan vs the non DPF 21" fan to keep it cool.

Low RPM high load will spike the temps higher due to slower coolant movement and low fan RPM, radiator heating delay, less hot air over the slow spinning fan to heat the spring, and slow movement of the working fluid in the fan clutch due to lower RPM. All that spikes the temp to 210 on my truck towing when I get a heavy grade. When I hit a WOT grade the temp does not spike as high before the fan is locked in and holding the temp from climbing.

So the harder you push it and have it downshift the cooler the temp spike is before the fan locks in.
 
Acesneights1 said:
I used Heath tune and heath TM and ran hot which is why I am revising the turbulence idea. I mean my previous overheating posts always left everyone wondering why other than things just happen to me that can't be explained....:D
Click to expand...

Was the Heath tune and TM just on the dually, or was that common to the other experiences as well? It definately sounded advanced at idle, and I have seen the timing curves on some that I would not necessarily be comfortable towing with using a GMx without an intercooler or water injection. Ultimately, one cannot just blame fueling, because its a variable factor highly dependent on your foot. So you can always back out of it to stock levels of fueling.

But there are plenty of people that run with those programs and tow a lot. There may just have been a difference in speeds and expectations. One thing is for sure, if the fan clutch were to engage I cannot believe any engine would stay hot. That thing will pull a lot of air. If you kept the 2000 stock clutch it just needed a little bend on that bimetal coil and youd have been set, would never overheat then.

You could be the happy owner of a Burb that has a partially stuck clutch that is always dragging and partially engaged, or previously modified. Not good for MPG maybe.
 
I think the clutch is fine on the burb. Seems to do exactly what it's supposed to. The Tahoe and the Dually both had TM with Heath tunes. I had the Heath Severe duty cooling kit on the Tahoe and on the Dually the stock fan with a Hayden SD clutch. Same results both trucks but both truck I had the cats gutted and the 4 inch cut into the cat.
 
Edzzed said:
True enough, one only need look at my sig. Even with the ATT I can still generate some high egt's when towing only. But that could be due to having the HP4 vs. a towing tune.
Click to expand...

ATT with the old GLE Tune still shot the EGT's up a notch higher than with the GM-5. Updated Performance tune for ATT though has things much better. Biggest improvement for coooling my "210+ under its own weight" issues was swapping a catless 4" exhaust and mandrel bent cross over kits.
 
Yesterday I was junk yard scrounging, digging through 90s era Burbs and pickups, and one DMax pickup. Somewhere there I saw a fan that was either 11 or 13 blades (don't remember now which). When I saw that my first thought was "would this be any good for towing?". It was on a thread on fan clutch so it may have been the DMax.

Since you guys are talking fans at the moment, would this fan be worth grabbing?

Don
 
Acesneights1 said:
No prob...That 93 looked sweet. I thought you had a Kennedy fan ? I was gonna ask your opinion of it. Do you still have it ?
Click to expand...

I bought the Kennedy clutch W/ the 20" Steel blade that John swore by.......Well, it sucked, still got way too hot at idle W/ A/C on in traffic......Went out got a 21" D-Max plastic (Composite) blade,......problem solved.

On another note, the Kennedy Clutch was a little to early to engage and seemed like it never disengaged.....as many others have said before.....Tim had the same problem.

So even with the Kennedy clutch running like a bat out of hell, it was the BLADE that made all the difference....Too me, anyway.
 
handcannon said:
Yesterday I was junk yard scrounging, digging through 90s era Burbs and pickups, and one DMax pickup. Somewhere there I saw a fan that was either 11 or 13 blades (don't remember now which). When I saw that my first thought was "would this be any good for towing?". It was on a thread on fan clutch so it may have been the DMax.

Since you guys are talking fans at the moment, would this fan be worth grabbing?

Don
Click to expand...

Grab it if the price is right......Brand new D-Max blade can be had for about $50 bucks.
 
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