Carbureted LSX Forum - Carb'd 6.0 MPG




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Smitty454
03-27-2012, 11:09 PM
Sorry with another MPG question. Ive been considering going the carb route with a 6.0. What kind of gas mileage are you guys getting with a carb vs an efi setup?

I will be running a 6.0 with a decent cam, 6 speed manual and 4.10s in the rear if the MPG is reasonable.


Hugger67RSSS
03-27-2012, 11:34 PM
I should know all of the above sometime in the near future. Setup the same as you but 3.89 gears. I think it all depends on how often you want to tune on it

tennerv8
03-28-2012, 05:16 AM
Mine has been shitty lately mostly because of my converter. Which is a 3400 stall. If I'm driving under my stall speed then it's wasting energy through the converter. Also it revs at 3500 at 70mph. That's with a 27"tire and 373's with a th350.


NoShow
03-28-2012, 07:47 AM
If "decent cam" = less than 226 or so, with the 6-speed in a Chevelle, 750 carb, I would ball-park it at 16-17 mpg highway, maybe more if you run a A/F gauge to fine-tune your carb

Smitty454
03-28-2012, 10:08 PM
Does anyone have any actual proven numbers and not ballpark figures. I dont want to put this engine together and find that it gets a couple mpg's better than my 454.

Pop N Wood
03-29-2012, 05:19 AM
There have been multiple threads on this.

I'm running a 6.0L LS2 with the stock LS2 cam (i.e. LS6), 750 DP, 2500# car, TKO 5 speed, 3.54 rear and 25" tire. I turn about 2200 RPM at highway speeds and regularly get 25 mpg. In fact, my conversion is the economy car of the family.

Most guys with heavier/larger cars are pulling down 20's if they have a proper overdrive. Gearing is key in this case, not the induction method.

GNCLONE
04-10-2012, 08:19 PM
....and the mass of the vehicle

ZONES89RS
04-11-2012, 10:46 AM
T56 Trans, 27" tall tire, 4.30 gears, trex cam, I get bottom 20s driving normal.

Prorac1
04-11-2012, 01:12 PM
T56 Trans, 27" tall tire, 4.30 gears, trex cam, I get bottom 20s driving normal.

Wow, thats pretty impressive. What RPM do you run at.......................say 60 mph in 6th gear if I may ask. Again, impressive results for a carbed application IMHO. Eric L

ZONES89RS
04-11-2012, 01:32 PM
Have it dialed in to 14.7-15.0 AFR at cruise speed, 2000 rpm in 6th is 77 mph, lol.

gregsss
04-12-2012, 05:35 PM
Have it dialed in to 14.7-15.0 AFR at cruise speed, 2000 rpm in 6th is 77 mph, lol.

With 4.30 thats crazy good.

ZONES89RS
04-12-2012, 09:14 PM
Double over drive baby!

brngrhd
04-12-2012, 09:56 PM
with my old combo 3400 stall th400 3.89 28" tires on E85 i got 10 at 70ish :)

ZONES89RS
04-12-2012, 11:47 PM
E85 is not for economy, lol.

brngrhd
04-13-2012, 08:33 AM
No not at all.... Hell I was pretty happy with 10 LOL

Andy's Auto
04-13-2012, 03:16 PM
Not sure but my 78 Malibu is easily getting twice the mileage as my 81 505 BBC powered does. I have gotten 28 passes out of a tank where the 81 gets around 8. And I still have 1/4 tank.