Thinking about throwing in a s475 with .90 housing in my lb7? Wanna keep the stock sticks in for a bit! Anyone have that same setup and not like it?
Lb7 s475 on stock fuel?
- Thread starter USMC_53
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With a delicate right foot it would be driveable. Couldn't mash it from a stand still or tow with it though.
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I second this... I just started a thread about a month ago asking the difference of going for a 1.10 housing to a 0.90, i do know that with my current housing 1.10 i CAN'T tow heavy or even light on a grade. I attempted to tow my father-in-law's boat (about 5k) over a 7-10% mountain about a month ago... not good... egts (1200-1400), and engine temp way up... unlocked the converter to prevent smoking out the mountain then the trans temp pegged just as i got to the crest of the mountain... just ugly and not fun... but other than towing... i say do it!! :thumb:
I have been running a s475/83/.90 for years. With 40 overs. I DD the truck and tow heavy.
I have no problem pulling hills with another truck on the goose neck. I have also towed 2 pulling tractors weighing 8500 each.
When you hit a hill you have to take it out of O.D. keep the rpm's amd in boost. Egts stay right at 1000° pulling up hill.
I personally like driving a bid single more then a stock truck. Does not take much throttle to get into boost. With the right tuning.
I know he is on stock fuel but 40s arent that much more. And im still limited to stock cp3.
Have abused this truck for years with this setup with no issues.
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I have no problem pulling hills with another truck on the goose neck. I have also towed 2 pulling tractors weighing 8500 each.
When you hit a hill you have to take it out of O.D. keep the rpm's amd in boost. Egts stay right at 1000° pulling up hill.
I personally like driving a bid single more then a stock truck. Does not take much throttle to get into boost. With the right tuning.
I know he is on stock fuel but 40s arent that much more. And im still limited to stock cp3.
Have abused this truck for years with this setup with no issues.
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Why is everyone afraid of EGTs lately? I run a "smaller" turbo (S371) and an aggressive cam, so I run up hills at 1200-1350°F empty. Throw a trailer on and typically I'll have to drop a gear and get into the powerband (2200+ RPM), but EGTs still stay 1100°+. Have run this way for years, nothing ever melts.
Heck, cruising level highway at 80 MPH puts my EGTs at a hair over 900°, and I run that for 4 hour stretches.
To the OP, you can run a S475 on stock fuel, but EGTs will be higher than stock, lag will be WAY worse, but you can tow if you want to. You will need gauges, and will need to watch them, but it can be done.
Heck, cruising level highway at 80 MPH puts my EGTs at a hair over 900°, and I run that for 4 hour stretches.
To the OP, you can run a S475 on stock fuel, but EGTs will be higher than stock, lag will be WAY worse, but you can tow if you want to. You will need gauges, and will need to watch them, but it can be done.
Wow i need a 0.90 housing... I run at 800-1000 at mid throttle just crusing down the highway.
Dave... even downshifting so like 2200+ rpm, with enough throttle to not be embarrassingly slow i was seeing 1300-1400... is that "safe"??
I consider 1350°F safe for a long time (10+ minutes), just watch your coolant temp. I don't mind hitting 1400° for short bursts up hills, and have never had any problems. I start to get nervous above 1400°, even for just a minute. If in doubt, drop a gear to get the airflow up where the larger turbo is more efficient.Wow i need a 0.90 housing... I run at 800-1000 at mid throttle just crusing down the highway.
Dave... even downshifting so like 2200+ rpm, with enough throttle to not be embarrassingly slow i was seeing 1300-1400... is that "safe"??
The fact that your coolant and trans temps were climbing that quickly kind of implies something isn't right with your setup/driving. You shouldn't unlock your torque converter when towing, it just adds heat. I have found that with a trailer, 5th gear unlocked is the same RPM as 4th gear locked, but produces way more heat. If needed, you can drop another gear. The Duramax will pull all day at 3200 RPM, just get crap mileage.
Engine coolant temps can be addressed a number of ways. James (Chevy1925) has posted his adventures in controlling ECT with big power and heavy loads.
It is all in the tuning. It can be done safely, but you can't go max effort tune for sure. Any good tuner (ATP, Kory, etc, etc) will be able to keep your engine together with compounds.
Thanks for the input! I'm kinda wanting to try towing it again just to see how it handles. Oh, important factor that I forgot to mention is I have a 3000 stall converter... that makes it suck even more (when unlocked that is)
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I'd recommend running the 87 turbine
Who knows why. I stopped watching egts.
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Who knows why. I stopped watching egts.
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Wow i need a 0.90 housing... I run at 800-1000 at mid throttle just crusing down the highway.
Dave... even downshifting so like 2200+ rpm, with enough throttle to not be embarrassingly slow i was seeing 1300-1400... is that "safe"??
dont drop your money on that housing yet. you need to see when boost starts coming on with that turbo and make sure you have 0 boost leaks. Then let that engine rev next time you are pulling something. get it up to 2500-2600 rpm and see how it does. i pull at that RPM all the time on hills, even up to 2800rpm for minutes at a time. changing housings will net you about 200-300 RPM drop in spool up time though if everything is well.
Dave pretty much nailed it. another issue will be outside temp. out here, when you start breaking 90*, spool up time and getting on top of that charger starts getting hard to do. when its 110*, its rough. add to that a heat soaked intercooler, cooling system, and very hot exhaust system when towing/pulling hills and getting that turbo to come can be a bitch. what i mean by this is cruising along in 5th gear or 6th gear on a single turbo towing a good sized load, not staging the truck at the line. there is no way i would get a 475 to spool in 5th gear at 2100rpm in those temps and 15k on the back, i may as well stay in 4th gear.
you can definitely make a single tow heavy, you jsut have to have rpm to do it so you may be downshifting alot.
Thanks for the input James, I will pressure test and see what I find. How much effect does EGT's have on ECT? Should I be able to pull 7% grade for 5 straight minutes at 1200-1300* and not have climbing engine temp (Given a 70-80* day)? BTW my apologizes OP, I've completely hijacked this thread...
EGT's usually dont coincide with ECT. you can have 1000 degree EGT and still get 240 coolant temp. when i pull hills during the summer im generally at 1100-1200 for long periods of time like dave said but i can hit 240* coolant temps fast. thats in 4th gear, 2600rpm, and 55-60mph with 15k. but when its 40-60* temps out side, i can pull the very same hills in 5th gear, 1100egt, 70mph and coolant never goes over 220* with 15k on the back. i can drive it significantly harder in the winter than the summer just because the outside air temp will actually knock temps out of my cooling system. its an eerie feeling seeing 45psi of boost, being in 5th gear and hearing that turbo whistling harder than hell as you pull that much weight up a hill during the winter time.
with the boat you posted, you should be able to pull that grade for that long at that egt and air temp without issue. really, you should be able to knock it down a gear with that light load and be even less egts. the higher rpm will also let the fan draw more air in and keep temps at a better level too. engine will be working easier as well.
with the boat you posted, you should be able to pull that grade for that long at that egt and air temp without issue. really, you should be able to knock it down a gear with that light load and be even less egts. the higher rpm will also let the fan draw more air in and keep temps at a better level too. engine will be working easier as well.
Roger! Thanks again for all your input. I'm feeling alot better about my setup now. I want to dig in and see if i'm losing any boost anywhere. If i get that squared away i'll probably go to the .90 housing anyways just for that extra spool-ability. Thanks!:thumb:
So should I run something smaller you think? I never tow anything, hell I don't even have a hitch... got rid of it when I did my roll pan and never bought the big Chevy hitch they sell, anyway Maybe something smaller but still in s400 or what about s369? Don't want to trash my rods just yet, need the trucks internals to last a little bit longer.
General consensus is: the smaller the turbo, the faster the spool, the faster a rod goes.