mrarmyant

I'm dropping an LM7 (or L33 should I get lucky and find someone that isn't wanting LS1 prices for one) in my first gen 4Runner. The LM7/L33 has way more power than what I really want the truck to be putting it up with, on accident really. I love the motor though, had one I swapped in my Jeep. I might be rebuilding the motor (and if I can find an L33 block adding that) but was wondering if anyone had built a motor in the other direction, one soley based on fuel economy? I could drop down to 250hp and still be happy (thought about the V6 but its about the same price around here, I can get an LM7 for about 350.)

So any tips? Fuel efficient ECM tunes? Cams? I assume increasing flow will always help efficiency. Anything to replace to reduce friction?

wildcamaro

iTrader: (15)

If i was you i would get a 4.8 if gas mileage is your deal...you would still get 295 hp and 300 tq, but the only way to dial back the motor for fuel economy would be to custom spec a cam with less lift and duration than a stock 4.8 cam which would be TINY...i like your idea though because i havent seen anyone on here shoot for fuel economy...

wildcamaro

iTrader: (15)

I forgot to add this but if you detune the motor too much bc you will be hurting fuel economy bc a weak motor will have to strain to pull around that
4x4 truck...i think you would get best econmy with a 4.8 which should be DIRT cheap

mrarmyant

The motor I found for 350 might be a 4.8. Has that darn unhelpful casting. I know if I detune it too much it could hurt but the original motor out of it got about 16mpg with 112hp. I wonder what a 4.8 cam in a 5.3 would do. I guess if the 4.8 and 5.3 shared the same block I could still get an aluminum block and make an aluminum 4.8l.

wildcamaro

iTrader: (15)

you are right on that an aluminum 4.8 would probably be a first...by the way an l33 is 9.9:1 motor compared to the 5.3 and 4.8 are considerably lower...just figured i would let you know, i only say that because i am currently building an L33 for my 81 camaro

mrarmyant

Hmm. I'd probably just take all of the internals of the 4.8l and put them in the l33 block. What did you get your l33 for?

I remembered that the comp is a little higher. Is it the LM4 that the compression is the same but still an aluminum block?

If I could find a working l33 cheap I'd just stick with that but 1500 for one when an ls1 is 1700 just doesnt make sense. And a this 4.8 or 5.3 unknown is 350 and I think I can find an aluminum l33 block for 200...

So do roller rockers help reduce friction any? Any alternators that are better than others (this motor is missing it's alternator and starter)

wildcamaro

iTrader: (15)

l33 is the gen 3 aluminum 5.3, and i believ the lh6 is the gen 4 aluminum 5.3...and yes the compression is almost 10 to 1 on the l33...

I got my 200k mile L33 long block, wire harness, intake, exhaust manifolds for $300...but the guy took awesome care of it...mot a bit of sludge, he must of used good sythetic oil every 3000miles because it has that great gold tint on all the internals...Im rebuilding it nonetheless

roller rockers would reduce friction, BUT the are heavier than the stock rockers fulcrum wise, which is where it counts...so the less friction comes at a weight gain on the rocker, always a comprimise....i would keep the stock rockers because they are a quality piece

dirty_old_chevy

What is your cruising RPM going to be? If its going to be over 2000, I'll bet a slightly bigger cam will help you on the highway. Not much bigger, an Ls1 cam maybe. Other than that, I'd say just get a good used 4.8 and mill the heads a bit, non-restrictive exhaust, and e-fans (which you'll probably be running anyway), and maybe get a tuner who deals with EFILive to set up a Lean Cruise for you.

wildcamaro

iTrader: (15)

Thats another thing i would do is change the gearing to like 2.73s bc you will be able to cruise at 65mph at 1650 rpms which is gas mileage city

mrarmyant

There was another aluminum block before the L33 used in the SSR, I think it was called the LM4.

Did you find that motor on craigslist or where? I might just wait then. Would be a real pain if I did all this to find out the cheap motor is a 5.3l.

I still have to find a transmission so I have no idea what final drive is. I also need to see what rear end came stock with the 22RTE. It is running 31's right now and I would like to maybe go to 33s which should help with gearing. While it will hurt fuel economy substantially my truck also weighs about 3400 as it sits right now.

Does anyone make block hugger long tubes? Any recommended torque converters? Has anyone weight rockers to see who makes the lightest weight ones then?

trans_am7935

iTrader: (15)

porting the heads will save you on gas mileage

wildcamaro

iTrader: (15)

Yea i found it on craigslist....funny thing is i already had an iron 5.3 when i bought it lol! after i bought the L33 i sold the iron 5.3 for $900...best deal ive made in a while

hammertime

iTrader: (1)

If you want economy, shop around for one of the later 5.3's with active fuel management, then see what a tuner can do for you to tweak things to maintain cruise with 4 cylinders as much as possible.

Other than headers, which you might need anyway, I don't see you getting your return on investment from any other performance parts in the quest for economy.

mrarmyant

Well the return is nice but a lot of it is keeping power in check for the toyota transfercase and axles which were never meant to be behind v8 torque and hp numbers.

hammertime

iTrader: (1)

If you are going to go four wheeling with the setup, a lot will depend on how you treat it. Nobody broke a weak factory 10 bolt driving grandma to the grocery store, but guys find ways to break bigger better parts like 12 bolts and 9 inch ford rears.

Your right foot will make (or break) both goals.

mrarmyant

Agreed. I had 1 tons under my jeep but prefer ifs and running higher speeds in the desert. Would rather have the build be overly reliable if anything though.

chrisfrost

iTrader: (8)

Not sure if anyone has mentioned this but the 4.8 and the 5.3 are using the same cam that is the non high performance 1's . fuel economy ,,,,,,4,8L , stock cam ,,,,,because the stroke is a little shorter You probably could get away with 11.5/1 or maybe 12/1 static compression if You use an oversized radiator .????? and/or lower t-stat .

mrarmyant

Well I found an l33 aluminum 5.3 cheap and I'm going to snag the mystery 5.3l/4,8l I think. One of the heads on the l33 is apparently messed (studs on manifold ripped out) so I was going to toss them then realized they were basically ls6 heads. Depending on the damage when it gets shipped here I might thread cert it and port them. If they have better flow like the ls6 heads I might as well use them with the lower performance cams and smaller 4.8l stroke. I'm sure someone will buy the cams... Also I think I've decided on ls9 hgs. Does anyone make lower coefficient bearings or anything?

mrarmyant

Also who makes the tightest block hugger headers? (long tube or short tube)

chrisfrost

iTrader: (8)

I'm not aware of any LT's that are block hugger but maybe someone else knows of some ?