Zizzle

This will not be a sexy build.

First some background:

I recently bought a 97 3500 express van nice and cheap. The high mileage 5.7 is disappointingly tired. Rather than dump money into that I'm thinking LM7 swap with turbo.

We live at 7000ft above sea level, and have to go over a 9,000ft pass quite often. Van is for carrying dirt bikes while towing a camper. Also to occassionally tow a car hauler with some other broken vehicle.

Not looking for huge HP numbers or a great deal of speed just some mild reliable HP. Ability to overtake uphill with a load when necessary. Good fuel economy when empty.

Hence I'm thinking no 6.0 or big block, just a 5.3 with a turbo to help feed it the thin air.

Just a few PSI to help it get back to sea level performance and a bit extra. A turbo that spools relatively low in the rev range.

Ideally no engine mods. The swap and plumbing will be a big enough project.

I have a lot of questions of course, but lets start with the premise.

Does this sound reasonable?

I have been trying to do my research.

Mounting the turbo something like this:

Turbo AWD full size van lives - LS1TECH

I have read this article:

594HP 5.3L Gen III Small Block for $3,252

Which says

So I was thinking 5-6 psi max.

It it as simple as piping a turbo to the 5.3?
Will the stock injectors be up to this? MAP sensor? MAF? Everything else?

Will a 5.3 PCM be up to the task with just a tune?
What sort of turbo should I be looking for that spools without too many revs?

53bowtie

iTrader: (6)

I have no forced induction experience but here are my thoughts:

1) In your application there is no replacement for displacement. Do you think you will really get that great of an increase in gas mileage in a 1 ton van by going 5.3 instead of 6.0? What if you go 6.0 and can keep it out of boost 70% of the time where as the 5.3 has to be in boost a majority of the time due to load?
2) To size a turbo small enough to spool at low RPM means loaded or unloaded you will be in boost more times than not. There goes your mpg.....
3) Having the performance of a 5.3 at sea level would be hardly adequate in my eyes for a 1 ton van let alone hauling/towing anything on top of that.
4) If it were me I would go with a 6.0 and roots style blower. This will give you the best low range of any FI option which will allow you to haul/tow anything you wish. Plus, when the van is empty you might be able to keep it out of boost most of the time to get a bit better mpg, although, I hope your not building a 1 ton van hoping to get 18 in town and 20 on the highway.....

Just my thoughts, take them with a grain of salt as I have no personal experience with FI in a 1 ton van. Hopefully others will chime in with more experience......

JGTurbo

^ No forced induction experience huh?

With a turbo, you won't be "in boost" unless you want to be. You'll still run vacuum down the highway.

I think a turbo would be perfect for what you're wanting to do. Diesels pull like they do because they're turbocharged. A gas engine with a good turbo pulls really well too. Just be conservative with ignition timing and enjoy your new-found torque.

I'd definitely recommend injectors, a fuel pump, and tune (possibly 2 bar map as well, just depends on how you want to tune it).

Want hot intake temps coupled with high parasitic losses and crappy mileage? Go roots.

Want it to drive like stock until you hit a hill and need some more power? Go turbo.

FWIW, I drive a turbocharged 4 cylinder pickup. I've towed with it on occasion and it pulls really well. No more downshifting and screaming rpms, just lots of usable torque. Also, I gained a couple highway mpg after I installed the turbo.

gamble686

iTrader: (3)

I think we are jumping ahead of ourselves a little bit. First I would suggest you handle the motor swap. A 6.0 is a significantly better starting point for a tow rig of your size. Handle all the details of that swap and then you can start worrying about FI. A turbo can be fun, but not as simple as a TVS kit. Either one will net you great results. Work out the motor swap details first. Then you can move on the the FI stuff. Save yourself some headache.

Show-n-go5.3

Agreed, motor swaps are a big enough headache it self let alone the time it takes to tune a forced induction set up. One thing at a time. 5.3 with the right cam or a 6.0 will be a drastic improvement over that ol 5.7.

Zizzle

Just to follow up: been busy doing this.

Accidentally ended up with a 4.8 instead of a 5.3.

Build thread:

https://www.performancetrucks.net/fo...-8-van-539084/

Thanks for the advice, I think JGTurbo was on the money.

I came across no 6.0 motors for sale around me. Searching wider I could find them but for more money than a turbo setup.

I'm pretty happy with how it turned out so far. We'll see how it holds up over time. But it's not being raced and will probably only do a couple thousand miles a year tops, so I'm optimistic.

kbracing96

iTrader: (26)

<<< Turbo guy here, lol. 4.8 with BW S366 turbo will do wonders for towing and high elevation. ( I grew up in SE WY so no stranger to elevation )

Edit: I wrote this before I read your build and you did exactly what I would have done!! lol Nice job!

Zizzle

I did let this comment temper my fuel economy expectations a little. After all the van weighs 6,000+ lbs and has the aero of the side of a house.

But it does cruise at under 2000 rpm at the local speed limits (60mph).

A turbo won't necessarily affect cruising MPG. But I didn't really run the van NA after the 4.8 swap so I didn't have any baseline expectations.

As it's set up, it will build boost under load (uphill) at around 2500. When towing the load is obviously increased and it builds boost even lower. The real battle is that the trans wants to kick down when really is easily able to hold the higher gear -- more tuning needed there.

After getting the WOT fueling dialed in, I recently turned my attention to economy. My idle was too rich, and I eventually worked out my min injector pulse was too big. I'm used to manual trans, so I like engine braking -- I fiddled with DFCO to make it pretty aggressive.

I'm still fiddling with my engine tune - I can still add back a bit of timing I think.

But last trip into town empty I was indeed getting a bit over 20 MPG.