MPG Machine
MPG Machine 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?
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?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
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.
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.
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.
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.
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.
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.
On The Tree
Joined: Jul 2011
Posts: 149
Likes: 3
From: Maine
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.
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TECH Enthusiast
Joined: Mar 2012
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Likes: 3
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.
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.
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.
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.
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.
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.
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.
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.
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?
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?
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.
I did the swap myself and have about 13k into it. If you get some good deals you could keep it under 12.
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.
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.
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.
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.
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.
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.
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.
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.
Last edited by garys 68; Jan 21, 2014 at 01:14 PM.