EB 91 Tow/Perf tune, Use with Caution!
08-02-2016, 08:27 PM
#11
Senior Member
Thread Starter
I wonder if having Max Tow has increased cooling system. I don't have any tow package other than the hitch and brake controller(which works great). I also have 3:15 gears, which may contribute to the issue. When I towed stock, no problems, but the trans did hit 235*.
08-03-2016, 07:39 AM
#13
The tow package and max tow both have an external 4 row transmission cooler and larger capacity radiators. If you dont have a tow package, then yes that is partially why it heated up on you.
08-03-2016, 03:27 PM
#14
Yes all of those things are reasons why you overheated. I wound not expect that out of a tow or max tow truck as their whole cooling system is heavier duty. If it's a problem, you could pick up a radiator from full race and throw on a 13 row trans cooler from the v10 excursions and you will never have an issue again.
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acdii (08-03-2016)
08-03-2016, 04:48 PM
#15
Senior Member
08-03-2016, 05:35 PM
#16
Senior Member
I discovered the tune puts out MORE power than the cooling system can handle, so if you plan to tow a heavy trailer up a 6% grade, be cautious on the go pedal. It can easily do 65 MPH up a 6% grade pulling 6500#, but the cooling system gets quickly overwhelmed. It overheated on me once, and went into reduced power twice. I returned it to stock for my return trip and while it couldnt pull the same grades at 65 MPH, it still was able to pull past 5.0 with similar trailers. Good engine, but man does it suck up the gas. I put the tune back on once I got through the mountains, and didn't have any more issues.
Just beware if you run a tune in the EB, don't push it up a mountain with a load, use it with caution.
One side effect of overheating and too much boost, there is a rubber fitting on the intake that blew. I heard a POP then HISSSS, and lost power. I pulled into the first rest area and looked around and found this nipple on an extension that was blown out on the bottom. I was able to get to my destination with the hissing, but it totally screwed with the fuel mixture and boost and threw a bunch of codes. Would have been nice to have boost gauges to see how much pressure the turbos where pumping in going up that mountain.
Just beware if you run a tune in the EB, don't push it up a mountain with a load, use it with caution.
One side effect of overheating and too much boost, there is a rubber fitting on the intake that blew. I heard a POP then HISSSS, and lost power. I pulled into the first rest area and looked around and found this nipple on an extension that was blown out on the bottom. I was able to get to my destination with the hissing, but it totally screwed with the fuel mixture and boost and threw a bunch of codes. Would have been nice to have boost gauges to see how much pressure the turbos where pumping in going up that mountain.
Of course, who knows, maybe those 5.0's had 3.73's, maybe they had 3.31's but none of that matters, all that mattered is that an EB towed better than a 5.0 (which by now, we all know so big effing deal). I know when I'm towing I'm not looking around going hey, I'm passing that XXX, I'm focused on what I'm doing. I don't really care what I'm passing...and I haven't found anything that has slowed me down, lose a little speed, push the foot a little farther, if it downshifts, it downshifts, almost always stays below 3500 rpm and that's barely over half of the revs it is capable of turning.
Probably wouldn't have bothered posting except for the first quoted post.
OP, that is the first I've heard of a tuned EB overheating while towing, I'd have a conversation with whoever you got the tune from. Something doesn't seem right. Glad it still towed fine for you stock.
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acdii (08-03-2016)
08-03-2016, 09:47 PM
#17
Senior Member
Thread Starter
Yes all of those things are reasons why you overheated. I wound not expect that out of a tow or max tow truck as their whole cooling system is heavier duty. If it's a problem, you could pick up a radiator from full race and throw on a 13 row trans cooler from the v10 excursions and you will never have an issue again.
There is a cooler in front of the radiator, but don't know what it is for without tracing it. It heated up fast when tuned, so in my opinion it was the tune that caused it.
Main reason I started this thread, if someone has a tuned EB and plans to do some towing up grades, but doesn't have Max Tow or other tow package, which means having tall gears like my 3.15, use it with caution. Keep an eye on the temp gauge. For my part, lesson learned, thankfully not an expensive lesson.
Funny thing is, the past two days going to and from work the truck has been limber and getting over 21 MPG. It acts as though the heavy towing cleaned it out, which it probably did. I have the 87 tune in it, which I put back in right after Colorado. It hasn't run this good in quite some time.
08-03-2016, 10:27 PM
#18
I have no tune. (I do have mojo tho
) and had no problems on a trip to Florida this summer. You may have crossed mountains much longer and higher than I did in Tennessee.
08-04-2016, 01:17 PM
#19
Senior Member
Thread Starter
Yep thats the one. The summit of the one I heated up on was 11,000+ feet. the return side just over 10,000 feet.
I was going through my receipts for fuel and discovered the midgrade is only 87, and I had put in a midgrade fuel prior to the mountain because the station only had regular and "premium", which their version of "premium" was 87 octane. That may have played a part in it. Quite possible that the 91 tune adjusted for the 87 grade and used more fuel than it would have at real premium grades. I do know that from now on, running through mountains, I am just going to stick with the stock tune and 87 octane, since I know the truck can pull just fine with it and not overheat. I'll leave the tune for when I am not towing since other than more power, there is no added benefit for fuel economy.
I was going through my receipts for fuel and discovered the midgrade is only 87, and I had put in a midgrade fuel prior to the mountain because the station only had regular and "premium", which their version of "premium" was 87 octane. That may have played a part in it. Quite possible that the 91 tune adjusted for the 87 grade and used more fuel than it would have at real premium grades. I do know that from now on, running through mountains, I am just going to stick with the stock tune and 87 octane, since I know the truck can pull just fine with it and not overheat. I'll leave the tune for when I am not towing since other than more power, there is no added benefit for fuel economy.
08-04-2016, 11:54 PM
#20
Is that radiator about two inches tall and runs the length of the engine radiator? IF so then that is your tranny cooler and getting a bigger one won't help. The reason is that there is a thermostatic switch in the transmission that will allow the flow of transmission fluid only at certain temperatures.
I have no tune. (I do have mojo tho) and had no problems on a trip to Florida this summer. You may have crossed mountains much longer and higher than I did in Tennessee.
I have no tune. (I do have mojo tho
) and had no problems on a trip to Florida this summer. You may have crossed mountains much longer and higher than I did in Tennessee.