GrampasBuick

This forum is generally about performance, I get it, but I have an idea that I haven't seen done before.

I have a 99 Suburban K2500 (don't worry, I have a fast car too) with a 454/4L80e. I use it for towing fairly regularly, and I gotta say I'm disappointed. I didn't expect it to be good on gas, but it's really bad. I can handle that, but it doesn't have nearly the power to justify it. I'm going to do some fuel system upgrades, but I doubt they will help that much.
People love these motors for towing, I don't get it.
I'm thinking a 5.3 for economy when I'm empty, with a small turbo for when I need the power. Small turbo for quick spool and also because I'm not looking for huge power. Maybe 500 ft-lbs, horsepower is less of a concern (though it won't hurt!
I have a plenty stout drivetrain, so no worries there. But I live in Colorado and often tow 7000 lbs through the mountain passes. If I have to be on the gas hard, under boost, uphill, with a trailer, for say 10 or 20 minutes straight of unrelenting climbing... Is that the kind of thing that melts rings or otherwise breaks things?

drew408

I had a 454 vortec truck.

Mods were 30lb SVO red tops,CAI,elec fans,tune,hooker headers,dual 2.5" exhaust,UD pulley,and a top running truck. Made 245hp/380tq at the rear wheels. Before the tune,it was 221hp/350tq. Stock I'd say 205hp/310tq at the rear wheels.

Mine towed great after the upgrades and if u kept your foot out of it,u could manage 15mpg. Stock was around 10.5mpg.

drew408

This was with 4.10 gears in a 3500 single cab LWB truck.

AnotherWs6

iTrader: (17)

I have nothing to add other than I have thought of this 1,000 times and the idea, when I come across it, gets poo-poo'd pretty quickly.

That being said, I want to throw up at those power figures drew408 posted. Eww. 200hp big block = The automotive world went through some dark times. For about 30 years.

GrampasBuick

But why? Why do people scoff at it? Maybe they know something I don't? All I ever hear about is how durable these motors are, and with a little boost it seems like it would be a winner. If there is a reason, a specific reason, not some generic insult, as to why this is a bad idea, would someone share?
I'm not being sarcastic, I really am in the dark here.

And yeah, the 454 is 290hp/400tq factory, at the flywheel, so those rwhp numbers sound right.

I am doing the yellow top Bosch 4 hole injectors, I think anything bigger would need a tune being that I'm at high elevation. Also doing a new regulator. Also suspect it needs a filter.
Might do dual exhaust with an X muffler next. Might get disgusted and sell it.

etijsma

I was going thru a similar issue. Had a 07 NBS silverado 4.8 with some bolt on to gain a little power to pull the camper better. Told the wife I wanted to supercharge it but she didn't see the point to drop that kind of money in it. A month ago we got a 2015 duramax.

drew408

I wouldn't go with stock replacement 19# injectors,even for as weak as they are, SVO 30# red tops can be had for $100 and they drop in....spend $150 extra and u can get the tune to go with them,tune will really wake your truck up. Trust me....stock replacement injectors are gonna run you $250+ anyways,might as well get bigger/better injectors and a tune for the same price!!!

Drop in a good set of plugs gapped at .045 while u are at it. Stock is gapped at .065 and it will blow out spark on even a stock truck.

Have fun replacing that FP reg,it's a bitch to get too!!!

I assume u have the long start problem?

drew408

You'll spend a lot to get a 5.3 to 380ft lb of tq at the rear wheels.

Much cheaper to mod the 454. I spent about $1000-$1200 on mods. Truck also had an 80mm TB,dyno tune,H pipe in the exhaust,and live wires ign module.

A big block will take a hell of a lot of abuse.....dare I say probably just as much as the stock 5.3. I don't doubt the 454 vortec would hold 750hp turbocharged in all stock configuration.

You'll spend $2000 plus tuning and injectors(call that $500) if u already have the 5.3. It'd probably make 390hp/450tq at the wheels on 7-9# which is as far as I'd lean on it towing. And it'd make that power a lot higher in the rev range than a NA 454 with vortec heads.

Nothing beats cubic inches for towing.

stevieturbo

If it is built and tuned correctly then 20 minutes on boost should pose no issues at all, especially as overall it would still be a fairly mild build.

A Single S366 would probably work well or maybe something a fraction larger.

AnotherWs6

iTrader: (17)

I disagree on the much higher rpm comment. If your going for max power, yeah, its gonna get higher up there. But a properly sized smallish turbo wont need any rpm at all to produce torque. Which is part of the reason why all of the car manufacturers are going to turbo 4 cylinders. And their torque peaks usually start in the low 2,000's and keep it going for another couple of thousand rpm.

I'm a vw guy and have owned 6 of them in the past 10 years. The last 5 - which had a 2.0 turbo in a few different guises - were amazing. It has just an INITIAL dead spot. Then you just ride on a wave of torque. The cars were all so much quicker than their specs would indicate. Peak poer numbers dont always tell the story. A good 2.0 turbo can be quicker than a bigger V6 etc just because it is a BETTER MOTOR. The LS1's proved this. 300 HP and 3,500 lbs should not be able to pull off 12 second ET's. Slap a 300 HP 350 into a 4th gen f-body and see what happens.

That being said, put a small turbo on a stock 5.3, run premium, and shoot for 400 rwhp on a dyno. If done right ----- torque down low and midrange all day long. For a motor that never revs past four grand, like most truck motors. Take what GM gave us, add a few quick pounds of boost.

dburt86

iTrader: (2)

What about boosting the big block?

drew408

Show me a
Dyno graph of a 5.3 turbo making 350ft lb at 1600rpm.....hell,I'll even take an engine dyno.

c0ncEpT

iTrader: (4)

Kurt Urban put something like 100,000 miles on his turbo 6.0 shop truck back in the day before he tore down the engine for updates.

I'd do it just for the hell of it if your looking for a project.

TA63

iTrader: (5)

The heavy duty axles, 10 ply tires, and 4L80E suck up a ton of power. 6.0 trucks today aren't glamorous on a dyno either.

GrampasBuick

You assume correct.
Well, I wish I posted this earlier, I already bought the yellow tops. They will arrive tomorrow. That's what everybody on the truck forums recommended.

I think it's pretty pathetic that with 7 and a half liters of big block, my truck can't even break it's tires loose. Don't get me wrong, I didn't buy the truck to do burnouts, but jeeze, I can't even get a chirp. No matter how hard I try. Maybe if I wound it up and neutral-dropped it, but I'm not a 16 year old idiot anymore.

xleilvparc

I want to throw up at those power figures drew408 posted.

drew408

Your mistake,those guys on he truck forums all have stock trucks and BIG dreams.

As sad as those power numbers are,mine was the only truck I could find that had been on a dyno!! And it was the most modded 1 I could find even tho it was just a bolt on truck.

The hp sucked but the tq kicked ***. I figure the drivetrain sucked 25% from the crank hp/tq numbers. That'd make it 310hp/475tq at the crank. And mine did have 10 ply Michelins on H2 Hummer wheels that weighed a ton,the 4l80,and 4.10s and a posi with the monster 14 bolt. Truck weighed 6100# with 1/8 a tank and no driver. That's a 2wd,regular cab 1 ton pickup.Truck was also manual window/manual locks. I did put in the bucket seats and console out of a 98 Z71 tho.

The 454 Vortecs have a TINY cam that's supposedly installed advanced. Stock cam trucks really Peter out at 4500rpm.

A turbo 454 vortec would run circles around a turbo 5.3. That extra 125ci helps a lot.....you start doing mods like heads and camshaft,then it's a whole nother game. I've seen a 496 ci big block with peanut port heads make 485hp/575tq on an engine dyno.

That was a custom cam'd engine in the tow rig of a guy who builds offshore power boat racing engines.

stevieturbo

With an auto trans, would you ever see full throttle and be stuck in a high gear at 1600rpm ?

It was a bit like a bullshit claim BMW made years ago about their 2.5 turdodiesel making it's max torque around 1900rpm. Except with the auto trans, it was physically impossible to ever make use of 1900rpm

LsF-150

iTrader: (2)

Agreed, these motors are 8.0:1, just begging for 5-8lbs of turbo boost. I have the same motor in a wrecker and want to turbo it soo bad. Have thought about doing a budget deal with a used turbo from a cummins, no intercooler I think it could be done real cheap with great results. The holsets from a cummins would work well I think. They're all done by 3500-4000 just like your current setup. In your situation I would add meth injection, the cast pistons wouldn't like long hill climbs.

stevieturbo

type of piston wont matter as to duration.

Most OEM turbo setups use cast pistons and you'd be able to climb hill 24hours a day with no issue.