MrJuanderful

I am putting together a custom build for a Chevy 3500 work truck,9000lb loaded for work,and towing a 12k lb. equipment trailer about twice a week.However,80 % of mileage is unloaded back and forth,where minimal power is needed.

I am not going with diesel.Most towing is done on flat terrain,short trips up to 75 miles.

It is a compromise.My power needs can be wildly different,but I don't want to be burning up a ton of fuel just to have the power for when I need it less than 10% of the time. I have a 6.0 with 300K on it that I get by with.

I want to build a 5.3 turbo motor.I will switch completely to an e85 fuel system. I have plenty of fab experience and shop to work in. I also have an LSA supercharger on the shelf.I also have buddies with high HP turbo strip cars,but they obviously build for different purposes and RPM range.I need some grunt lower in the power band,and limit the RPM range to under 5500.

I am looking if someone has any experience with something like this. It is the long term reliability I wonder about.I have been poking around at LS1Tech for a little while now,and have a pretty good understanding of where to head on this.

Vortec350ss

iTrader: (20)

I dont have any first hand experience with it, but I dont think you can go wrong with either.

The blower will have more "power under the pedal" as soon as you touch it. The turbo will work very well while loaded as well.

If you go turbo use a large exhaust housing to keep heat in check and you wont need a very large compressor. I would probably look at the Borg 471 with the T6 1.32 AR housing. Its cheap and it will work well. Whats tricky with a gas motor is you don't want to make too much torque at too low of an RPM, they aren't built for it so you will break parts. The large exhaust housing will keep exhaust pressure in check and move the power to a usable range (2500ish or so). The small compressor will make it efficient on the 5.3 used as you intend to.

MrJuanderful

If I go turbo,I see myself going mid mount or even behind the cab with a stack,lol...this is going to be a big fab type project anyhow.I figure I can get all that heat out of the engine bay and have room for a nice neat intercooler setup.I can pull the intake air from 6 feet high if I want.I have ideas on how to keep temps sky high to the turbo.Does a custom mid mount setup have any chance of working for my needs?

BudRacing

iTrader: (3)

Not to be rude, but... why? There are a number of turbo manifolds available including cast pieces that easily bolt up under the hood with little to no compromise. Heat blankets and pipe wrapping can keep temps under control at a reasonable level. If this isn't a show truck or a rat rod, I see no reason in going through all of the lengths in fab work to make this happen.

Large intercoolers and trans coolers are easily run in the forward locations too.

Also, if you're going to be towing, I would probably stick with a 6.0 for the low end torque prior to spool.

MrJuanderful

Fair question.Without going into it all,it is a project that no doubt will take more than a year,that involves mucho work and a vintage cab swap.Firewall to radiator is going to be somewhat tight and squeezing an intercooler into the usual place may be rough.How the engine bay lays out with accessories and all is a work in progress.If there is a "kit" that works,it will take some doing.

On the other hand,I can install the exhaust and driveline on an open chassis.

swathdiver

There's no better replacement for displacement at those weights. However, let me ask this question. What generation truck is this and what transmission and axle ratios are you planning?

MrJuanderful

NV 4500 5 speed,I need PTO. Dana 80 rear.

I drive another similar spec truck daily,with a 6.0,over 300k miles.It runs well.Remember,I mentioned it probably logs 70% of its miles without trailer,tooling around at 65mph at 2200 rpm cruise with no throttle.I am sure a fresh 5.3 would make similar power curve and numbers,or better.

Another thing,Truck also travels frequently in the most jammed up,high traffic,roads on earth.Stop and go could last 2 hours.This is not everyday,depending on work scheduling.

I will run E85 full time.I have 5 stations in 5 mile radius,and I haven't even begun to pay attention for others pumping it.This opens up a lot of positives,Higher compression and cylinder pressures being one of them.Much cooler fuel charge being another.

swathdiver

So will the 5.3 essentially be a Gen III L59? You'd want more torque for stop and go driving and to get that load moving(truck alone and pulling trailer).

I don't know much about your trans but some quick googling says it's max GCWR is 21,000 lbs. Another site was more specific, but only 19,000 lbs with 4.56 to 5.13 gears. 4.10s were good for 17,000 lbs GCWR.

E85 is good stuff, my motor loves it as does my wallet.

MrJuanderful

The NV4500 is a decent transmission,nice thing is that 5th is over drive,nice for doing 70 mph with a 4:10 rear.It's got 2 ptos,I need that for equipment I run.It should handle power easy enough,Dodge used it behind the Cummins for several years.It seems to shift nicer to me than the SM465 Muncie I have had in several trucks over time.I have it a 94 one ton that is all used up and ready for the boneyard after I pick a few things off it.

I will use the best condition 5.3,low mileage engine that comes my way,as soon as I get word out,it wont cost me more than 500 or so.I am going to run the 706 heads,and probably new pistons and rings,leave the rest alone.Its going to be over 10:1 compression without boost and make decent torque on e85 that way.

swathdiver

Consider also the L33 with 243 heads, it was the highest horsepower and torque rated Gen III 5.3 motor. Compression is 9.9:1. However this engine was not FlexFuel like the L59. Are you going to run a carburetor or aftermarket fuel injection or the original?

Not sure a Gen IV computer setup would be friendly for what you want to do.