What kind of MPG are you STOCK LSx swappers getting? Help

[brrymnvette]

I'm thinking about picking up another Bu this weekend for a DD/beater. I've got a 5.3 that's 75% complete sitting here. Thinking about dropping it in over getting a used motor for the car since it needs a motor. I'm more concerned about getting decent MPG with it since I get 15 currently with my truck. I've had many LS cars and know the amazing motors pretty well.

SO, I'm at a crossroads. Get the car and throw a cheap-o 350 from a junk yard in there to get it going. Maybe $350 for the motor.

Or

Throw the 5.3 I have in it and get way better MPG and have more fun. I have the Motor, heads, intake, injector, truck fuel rail, water pump, truck wiring harness and PCM. All I need for the truck stuff to be complete is, alt, power steering, A/C, tensioners, misc sensors for the motor, motor mounts, exhaust, fans, rad.


I'm trying to do this as relatively cheaply as possible. But if I spend a couple hundred more doing the 5.3 and getting 10+ better MPG, it will be worth it.

I haven't been following this site in the last year or two since I haven't had a g-body. But I can't stay away any longer. So, I'm not up on all the swap info and what works and doesn't. I've been reading topics on here tonight and will read most of them by tomorow.

 

[lt4malibu]

my stock LS1 with a 4l60e would get 22mpg combined city/highway(85% of it was highway driving). all depends on your driving style though.

 

[blubaldmontess]

Mine has a little bit of work done to it, an dit runs a 4.11 gear, but highway driving i'm averaging about 22-24 mpg, and in city I'm averaging about 15-17, but it does depend on driving style,and I drive it like I stole it every time I get behind the wheel, I also have the 6.0 under the hood too.

One suggestion if I may make it, you can reprogram the computer to run two different tunes, and a push button to make them work. You can have a programmer, or if you want to program it yourself, one for "economy mode" and one for "HP mode", think of it sort of like when your truck has that "Tow" option button, you push the button and the computer reprograms itself, you can do the same with a simple button on your center console or dash, good luck!

 

[brrymnvette]

One suggestion if I may make it, you can reprogram the computer to run two different tunes, and a push button to make them work. You can have a programmer, or if you want to program it yourself, one for "economy mode" and one for "HP mode", think of it sort of like when your truck has that "Tow" option button, you push the button and the computer reprograms itself, you can do the same with a simple button on your center console or dash, good luck!

That's prob what I'd end up doing. A lot of guys are doing that when they run the bottle. A tune for regular driving, and flip the switch, and now you're on the tune for the bottle. Lean cruise would help out a ton for DD duties. I spend most of my time on the hwy or under 30mph on the hwy.

 

[blubaldmontess]

Well then, its settled lol, time to get it going! If you need any help or have any questions/troubles finding parts, let us know, we've got lists for days eh?

 

[brrymnvette]

Well then, its settled lol, time to get it going! If you need any help or have any questions/troubles finding parts, let us know, we've got lists for days eh?

Yeah, this thread was geared towards talking myself into it with you guys' help. :lol:

 

[blubaldmontess]

Well hows this to help, in a year I put 5.5k miles on my car. Wo se'll do a breakdown. if I get 18 mpg I used--306 gallons

306x2.55 a gallon=$780 in gas last year

If I would have kept the old 383 stroker, with less power and a little less reliable and a lot more of a headache, at 10mpg (yeah I wish it was that good) I used--550 gallons

550x2.55 a gallon=1405

so in a year I saved about $625, and that was only doing 5500 miles. Now imagine if you drove 8 or 9k miles, you'll have saved almost the price of the swap in a year. Add onto that you've probably got a better rear gearing than I do, and you'll get better gas mileage than me.

Thats just one of many upsides, but basicaly what you spend at first will save you in the end, alot!

 

[455_82malibu]

20+ mpg with 3.73...and runs 10.7's cant do that with an old school V8