L$X$10

iTrader: (4)

I've been driving an 03 Yukon as a daily and the MPG is killing me. I've deleted the cats and had it tuned..even bought a set of longtubes for it...avg. MPG right now is 15.3...and that's with me driving in civil...not how I want to.

So.....I've decided to drive something that gets good gas mileage.
I can't bring myself to drive a Pirus, Camery or anything else along those lines.
So I figured...LSx conversion geared for fuel economy!

What's y'all's input on a decent looking, fair priced, LSx vehicle/swap say for under 12k?

HexenLord

Buy the smallest/lightest RWD car that'll be easiest to swap. I imagine a Miata with a 4th gen LSX would probably get great gas mileage.

G-Body

iTrader: (4)

Depends on what you want to build. A miata would be a good shot. I know someone who had a 5.3L in a 1978 buick electra 4 door with a th400 2.41 gears and the stock skinny tires and he was getting 25mpg on the highway. That dropped considerably when he swapped to 275 tires a 3.08 gear and a 4l80e, like 15-18. A third gen camaro would be a pretty easy swap and is light / aerodynamic enough that it should get good MPG.

As an alternative you could pick up a early 2000`s corvette. I have heard the guys with stick trans and longtubes claimed being able to hit 30mpg on the highway.

garys 68

iTrader: (1)

Go with a 4.8 or 5.3 in a relatively light car, and as tall gears as possible with an OD trans.
I built my DD 72 Olds 5.3 under 12k. It's getting combined low/mid 20s with 2.73 rear and manual trans.
Mid 80s G body or f body are cheap, parts readily available, already have hiway gears in the rear end, easy to swap. They're also big enough to be practical for an LSx V8.

Pop N Wood

iTrader: (1)

I'm getting 25 mpg with a carbureted LS2 in a Datsun 240z. Would do even better if I had a 6 speed with a steeper overdrive than the 5 speed.

Just keep the weight down, gear it appropriately and don't go stupid with a cam. Old Z cars, RX7, 240sx. Unfortunately I can't think of many domestics.

Keep in mind what ever you build, if you go V8 you will not get your money back in gas savings.

I just bought a Mazda 3. I'm getting 34 mpg going to and from work, no highway miles. Very nice car. I think the direct injection is what makes the engine so efficient, the compression ratio is 13:1 and it runs on regular gas.

zdiesel

5.3 in a volvo wagon! Should definitely be able to do the swap for well under $12k and with the right tire size, gear ratio, a good tune, etc... you should be able to see north of 28+ on the highway and the cool factor is there.

ramairetransam

iTrader: (18)

get a tdi . i get over 40 with my 2012 passat . slow as **** . but oh well .

fieroguru

iTrader: (1)

I have about 8K in my 88 Fiero with 5.3L LS4 and 6 speed manual. I think it has a good mix of power/performance and fuel economy.

HexenLord

If its gonna be something you drive everyday, make sure it'd something you can live with. Sure you can get a third gen camaro and drop some weight and get good mpg, but could you stand to drive a stripped down car?

That's why I said miata. Get an all aluminum 5.3, and it'll be 2500 lbs after the swap, and you won't have to give up any of the things that make it a nice car to try and keep costs down.

garys 68

iTrader: (1)

Don't most of the Miata swaps use an upgraded rear? Thinking that reasonable car, engine, trans, rear might push the project over his budget.
Thing a mid size that was available with a small block would be well within his budget, a lot easier, and more practical as a DD.

spacemanspif

iTrader: (5)

Do you need a family car or just a commuter car? For family think about a Volvo wagon (like mentioned above) or an Caprice. Pair it with a manual trans and good gears and you should be able to get good MPG.

If you just need a commuter think small as that should net you better mpg but stick with a manual trans. G-bodies are an easy swap and might be a good blend of small (2-door) but large (usable back seat). A 4 door Malibu or wagon might be the perfect car for your needs. If you go auto, get the 60e as it has a taller OD than the 80e.

How come no one has mentioned a DOD engine and keep the feature active? A Miata or S10 with a DOD engine would probably never run in 8cly mode during normal driving but would still have the power when you nail it.

AnotherWs6

iTrader: (17)

Uuuuuummmm, wait, WTF? Where can I see this thing? Do you have a build thread?

anarchy99

iTrader: (7)

Just go really small and do an austin healey sprite

cruisin'73

iTrader: (8)

Yes, do a Sprite build and then throw a built LS6 top with a supercharger and throw any speck of sanity or mileage out the window! Now that would be something to see!

anarchy99

iTrader: (7)

It's got an overdrive though!!!!

cam

iTrader: (9)

stock 4.8, th350, 2.39 final axle ratio and drive super easy. Should net 30+ mpg on the cheap too because whats the point of spending 12K on a swap to save a couple hundo per year on gas? You need to keep the swap cheap to justify the savings or your just gunning for mileage bragging rights which if you are? Although i wouldnt ever run one of these engines the best mileage would likely come from;

07+ 5.3 with AFM and VVT stock and tuned WELL!!! Tune is everything theres a guy on PT who tuned his stock GMT900 up to 24mpg or something like that. Swap that combo in a lightweight car and maybe 40 is reachable?

eng1nerd

iTrader: (2)

My LS1/T56 swapped IS300 weighs in at about 3200-3300. Family friendly 4 door, very comfortable daily driver. I am only getting about 15 mpg at the moment but I have a 3.73 LSD rear end in it and haven't gotten the tuning finalized. The only real highway miles I've done I got about 23 mpg.

I did the swap myself and have about 13k into it. If you get some good deals you could keep it under 12.

.boB

iTrader: (1)

Yes, a V8 Miata uses either a Ford 8.8 or Getrag center section or the IRS.

Adding an LSx to a Miata is not a technically difficult operation. It's been done hundreds of times, and all the parts are over the counter. Tap a few keys on the internet, and pretty soon all the parts will arrive at your door step.

BUT, it's not a cheap operation, either. The front sub frame alone is nearly $2K. With a used engine and transmission, and doing all the work yourself, it will cost $8-10K.

I think this is a key point: cost effectiveness. Don't plan on buying a project and swap things around to get better mileage. For example, it would cost you $15K to build a V8 Miata. But you can buy one ready to go for $12K. It's always cheaper to buy some one else's project than it is to do it yourself.

You really have to sit down with a calculator and see what you might be saving, and how long it take to get even. Lets pick on the Miata again.

Miata: 26mpg, 100,000 miles, $3.20 a gallon = $12,308
Yukon: 15mpg, 100,000 miles, #3.20 a gallon = $21,333
Difference in fuel costs = $9,025.

By the time you buy the used Miata, pay registration, insurance, taxes, and general upkeep over 100,000 miles, you'll have spent more than $9K. Assuming nothing disastrous happens, it will take you over 100,000 miles of driving the Miata to break even in fuel costs.

It's rarely cost effective to buy a second vehicle strictly for fuel mileage.

OTOH, it's hard to put a price on the fun factor.

gagliano7

When i had my 2001 camaro ss 6 speed stock i could get 30 mpg on the highway 18 mpg around town. You need something light and aero dynamic.

garys 68

iTrader: (1)

I've seen quite a few LS and SBF swaps, looks like a fun car with that kind of hp. Just kind of expensive.
As for a DD, I've been in a Miata, not the most practical. Might only be slightly more practical than my 68 LS corvette convertible
One other consideration here is emmisions testing. Pre OBDII cars just need a visual inspection. Post OBDII cars would show up on their computer with a lot of emmisions things missing.