To heavy a load??

[Herman_Bolger]

We just came back from a 600 mile trip. We have a mostly stock 1994 chev ext 4x4 dually, the only mods are a 4" exhaust (3" at the turbo), and a 3" cold air intake fed from a cowl hood.
We tow boats, this trip ( the first for this truck) we pulled a 29' searay that weights about 8500 lbs on a 4000 lb trailer, for a total of 12500 lbs.The air temp in the am was about 70f, once we got to the hyway we brought the truck up to about 60mph and things were not to bad, I did notice that the boost gauge would only go to about 2-3 lbs under heavy load, the exhaust temp(pre turbo) would max out about 1050f under load then come back down to about 850f and water temp would be about 195f, this is all on flat land.
Once we started getting into some small rolling hills the temps would climb very quickly and I would have to back off to about 50-55 mph. When I made it to the larger grades, I could not maintain speed and if I tried the temp gauges would climb very quickly, to 1150f exh, and 225 f water and would have to turn the heater on in the truck(oh ya it would be about 85f outside by now) to try keep things cool. Luckily it was the long weekend and traffic was slow and go so the truck had a chance to cool down between runs up the hills.
My questions, I am assuming the waste gate on the turbo is not working properly, would higher boost presures been able to make more power therfore not work the engine as hard and would have run cooler? The engine and rad are new (engine stock rebuild about 10,000m) would the '97 cooling upgrade make a worthwhile differance? How about intercooling? On my previuos truck (same configuration, except 7.4l gas) we pulled an 16,000lb load all the way from Texas to Detroit without any problems. Is this type of load to much for this truck?
I see some of the members pull some heavy campers, I thought with a boats pointy end (bow) it would be easier to tow.
We have put some money into an air ride rear susp, and a major body job, I really like the GM, but do I need to get another diesel? Or are these loads just to much??
Oh and just for info with this load we avg'd 9.8 m/gal loaded and 14m/gal with the empty trailer.

Thanks
Herman

[a5150nut]

Boost is to low. Check vacumme lines, waste gate accuater.
I use a potentiometer wired in to boost sensor and run 10 to 12 lbs boost. Sure helps with driveability. Stock you should see 7lbs boost. Get the turbo up to speed and you will enjoy towing.


Who's air ride did you go with, or did you build your own? I have toyed with the idea for my truck. That and NV5600, 3126 Cat and maybe that new RV trans Cat has out now. Lots of ideas, not enough money..........

[Robyn]

Hi
Check the vacuum at the turbo wastegate pod it should be 21 inches or more and steady, New is 26 plus and steady. If your vauum gauge is bouncing a lot and lower than 20 you need a vacuum pump. The other item to look at is the waste gate solenoid which is located on the left valve cover towards the rear and has two vacuum lines going to it and a two wire plug.
The vacuum to the wastegate should be checked at idle. If you have no vauum or low vacuum check directly at the pump and proceed from there to the solenoid.
Poor wastegate control = extra heat big time and poor power too.
You are pushing the envelope on the 6.5 with the weight you are towing but with the cooling mods and getting things working right you should do fine if you watch what your doing.
Sounds like you are keeping an eye on the gauges so your on top of things.
Let us know
Many smiles and a zillion miles
Robyn

[ronniejoe]

It's a stock 6.5... Although, it does sound like something is wrong in your boost control system.

Read the articles in my signature. Low power, high egt's and overheating are now a thing of the past!

[TurboDiverArt]

If you are going to pull such heavy loads I suggest an intercooler, probably the best investment you can make. As others have mentioned there is something definitely wrong with your boost control. Unless you were at like 3500 RPM's then 3 lbs with the stock programming is not right. Sounds like a leak. When I had a leak at the actuator I got 2-3 max. Assuming you are below 2800 rpm's you should be at about 7-9 psi stock. The cooling mods are also a significant upgrade to keeping things cool. If you were able the tow the way you are configured now I think you'll notice a tremendous difference by fixing the boost control, upgrading the cooling and intercooling. I would also suggest investing an extra $5 and put on a boost fooler. It

[Herman_Bolger]

Thanks for the insight, from a previous post I thought there may be a problem with the boost control, but we did not have a heavy load on to check with. Our boost control does not have any vacuum lines or wires to it, I am assuming it works on spring resistance of some sort,I am looking at getting a turbo master boost controler that I seen on kennedy's website.
Am also looking at getting the '97 cooling upgrade, but we have the mech pump and I read a lot of issues with the throttle cables?
An intercooler is on the wish list also, along with a gear drive. If I have to tear down the front to put in the water pump I may as well do the gear drive at the same time.
The air ride is our shop built, we looked one up on the net, (not sure right now which one) and through trial and error made our own, that part works awsome, no sway, nice ride.
I am going to read ronniejoe's articles and hopefully clairify a few muddy spots.
I am hoping to be able pull 30' boats behind this truck and trailer, for our bigger boats we looking to get a single axle tractor, and a bigger trailer, I see smaller trucks pulling large boats, I just figured a diesel would be easier than the gasser.

Thanks

Herman