Older Rig Updates: Cooling and Power
I thought I would post my latest updates to our Suburban. Had some nice weather yesterday and got some work done. In my last post, I had regeared from 3.73's to 4.56's. My truck and trailer specs a...
Forum Discussion
Just wanted to make a small update, since a lot of time these threads never get updated with results to help future searchers.
In short, the changes I made seemed to have fixed the cooling issues.
We made a long trip out to IL and back this summer to visit friends, during the killer heatwave that was going on.
A big bummer though, I had to go back to a factory 3.73 rear and the factory computer tuning. Not because I didn't like the 4.56's, but because there were some setup problems with the gears that would could not resolve in time for our summer trips. I have a parts truck here that happened to have 3.73's so I swapped them out.
I had a few long steep hills where the fastest the truck would go was 45mph in second, with my foot to the floor for minutes at a time. So full power at 3500rpm, with the AC on max. There were also other hills that required second, but I could go as fast as I was comfortable spinning the engine.
The highest the truck got was 210F...before the changes in this thread it would hit 230 with no indications of stopping, even with the AC off and the heater running to get us to a pullout where we could let it cool down.
So being able to motor up hills without everyone sweating and being generally miserable, was huge.
Personally, I feel the exhaust changes are the big player here. I'm not sure how much the fan does at 45mph, but engine is trying to move a lot of heat out the exhaust under full power for minutes at time, not just a few seconds fo quick acceleration unloaded.
The fan and HD clutch did great things for the AC at idle, and at low speeds, but it is LOUD! Fine with me though, if it does the job it is suppose to do.
I am currently shopping for a deal on a big block suburban or crew cab though. Wanted one for a while, and as we do more and more long trips it seems like a good time!
In short, the changes I made seemed to have fixed the cooling issues.
We made a long trip out to IL and back this summer to visit friends, during the killer heatwave that was going on.
A big bummer though, I had to go back to a factory 3.73 rear and the factory computer tuning. Not because I didn't like the 4.56's, but because there were some setup problems with the gears that would could not resolve in time for our summer trips. I have a parts truck here that happened to have 3.73's so I swapped them out.
I had a few long steep hills where the fastest the truck would go was 45mph in second, with my foot to the floor for minutes at a time. So full power at 3500rpm, with the AC on max. There were also other hills that required second, but I could go as fast as I was comfortable spinning the engine.
The highest the truck got was 210F...before the changes in this thread it would hit 230 with no indications of stopping, even with the AC off and the heater running to get us to a pullout where we could let it cool down.
So being able to motor up hills without everyone sweating and being generally miserable, was huge.
Personally, I feel the exhaust changes are the big player here. I'm not sure how much the fan does at 45mph, but engine is trying to move a lot of heat out the exhaust under full power for minutes at time, not just a few seconds fo quick acceleration unloaded.
The fan and HD clutch did great things for the AC at idle, and at low speeds, but it is LOUD! Fine with me though, if it does the job it is suppose to do.
I am currently shopping for a deal on a big block suburban or crew cab though. Wanted one for a while, and as we do more and more long trips it seems like a good time!
