turbo 4.8 l20 build for a tow rig?
09-18-2016, 02:22 PM
#1
On The Tree
Thread Starter
turbo 4.8 l20 build for a tow rig? Thinking about building a 4.8 for a tow truck, nothing real heavy just boat, small camper. What would be the downsides if any for going forward with this in say ...a mid nineties gm 3/4 ton extended cab truck. I have fab experience and a hoist to work on the project. Am I thinking correctly? Is this a feasible plan.
09-18-2016, 02:43 PM
#2
TECH Addict
I do not see why it wouldn't work. Just going to have to size everything (turbo, intercooler, cam, engine water and oil cooling systems) to be able to maintain boost for extended periods of time. But it is very do-able.
A naturally aspirated motor with more displacement would probably be a better choice, but that has nothing to do with your original question. I think a properly sized turbo, S366 maybe, and a decent stage one turbo cam from any reputable vendor on this site should set you straight. The obvious things like pushrods, head gaskets, lifters, valve springs, and rocker trunion upgrades still need to be addressed, as well as you fuel system. But I would imagine that all goes without saying.
A naturally aspirated motor with more displacement would probably be a better choice, but that has nothing to do with your original question. I think a properly sized turbo, S366 maybe, and a decent stage one turbo cam from any reputable vendor on this site should set you straight. The obvious things like pushrods, head gaskets, lifters, valve springs, and rocker trunion upgrades still need to be addressed, as well as you fuel system. But I would imagine that all goes without saying.
09-18-2016, 07:56 PM
#3
TECH Apprentice
Iv been very curious about the same thing for a while now. I wonder how a boosted tow pig would hold up under long hills and heavy loads etc. I go back and forth in my mind between a smaller turbo to keep it spooled in lower rpms, but then heat would become an issue so would it be smarter to go with something bigger and rev it higher? What im saying is its a good question lol.
09-18-2016, 08:38 PM
#4
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a big thing to think about will be gearing. Most chevy gas powered HD models will come with the 6.0 with 4.10 gears
IF it were me, I would look into a smaller turbo to spool quickly, a nice cam that will come in fairly early as others have noted and IF you have the budget I would look into a transmission that can get you into low (numerically speaking) over drive gears for high way cruising when you are not towing. My thoughts would be the 6l90e or a 4l80e. My personal 2015 silverado with the 5.3, 6 speed and 3.42 gears has pulled 8000-9000 pounds fairly easily for 150 mile stints. I routinely pull my dads 1970 c10 with a loaded bed of tools/jacks etc. on a 18 foot open deck trailer with a winch etc etc and it pulls it as if it isn't there. I obviously have to brake sooner, but the trailer brakes help out with that duty.
IF it were me, I would look into a smaller turbo to spool quickly, a nice cam that will come in fairly early as others have noted and IF you have the budget I would look into a transmission that can get you into low (numerically speaking) over drive gears for high way cruising when you are not towing. My thoughts would be the 6l90e or a 4l80e. My personal 2015 silverado with the 5.3, 6 speed and 3.42 gears has pulled 8000-9000 pounds fairly easily for 150 mile stints. I routinely pull my dads 1970 c10 with a loaded bed of tools/jacks etc. on a 18 foot open deck trailer with a winch etc etc and it pulls it as if it isn't there. I obviously have to brake sooner, but the trailer brakes help out with that duty.
09-19-2016, 04:55 AM
#6
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Without being all up in your business about everything, is there a little more you can elaborate on? What gear ratio in rear? What size turbo? What's your average weight you pull? How long have you ran that setup?
09-19-2016, 08:41 AM
#7
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It's a 2010 chevy 1500 4 door 4x4. 3.42 gears. It has an on3 70/65 and it is pretty responsive. I wish I had a small stall converter but once I'm rolling it doesn't matter. I have hauled my 9000lb mini excavator a few times and it had no issues getting up to speed or holding speed up a grade. I mostly use it to haul my wheeler around though, it weighs about 4.5k and the trailer is roughly 2.5k and I hardly know its behind me. truck had an l76 6.0 originally and the 4.8 turbo setup pulls much better. Oh and I'm only running 6-7lbs of boost. Don't have a boost controller yet. Have had the setup on the road for about a year with no issues.
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09-19-2016, 11:20 AM
#8
On The Tree
Thread Starter
It's a 2010 chevy 1500 4 door 4x4. 3.42 gears. It has an on3 70/65 and it is pretty responsive. I wish I had a small stall converter but once I'm rolling it doesn't matter. I have hauled my 9000lb mini excavator a few times and it had no issues getting up to speed or holding speed up a grade. I mostly use it to haul my wheeler around though, it weighs about 4.5k and the trailer is roughly 2.5k and I hardly know its behind me. truck had an l76 6.0 originally and the 4.8 turbo setup pulls much better. Oh and I'm only running 6-7lbs of boost. Don't have a boost controller yet. Have had the setup on the road for about a year with no issues.