Expected MPG?

[Erich]

Hey guys,
I have an '86 Cutlass with the 3.8L Buick 231 & THM200C and I'm about to take a road trip.

Wondering what kind of fuel economy I can expect? fueleconomy.gov lists 16 city/22 highway but I'm not sure how accurate that is. I want to know what other people with a similar setup are getting, car is mostly all stock.

Thanks guys,
Erich

 

[Lorenzo]

Well i know when i had my 86 Monte Carlo with 305, with a cam, and dual exhaust and 4bbl carb and everything running right i was only able to achieve a high of 19mpg combined. My worst was 8 mpg and average of about 16-18 ( and thats with keeping my foot out of it ) So id imagine with the 3.8 you should get the mileage its stating. MPG will always depend on how you drive. If you buy a new Chevy Cruze that says it can get 50mpg, it probably will.......if its rolling down a hill, in neutral, with the car off We have a cruze and maybe do we ever reach 40 or even 39 mpg. But if you take that same Cruze and stomp your foot down after every light your going to get the same mpg as a 305 v8

 

[DRIVEN]

I would expect no more than 18 with your combination. You might get lucky and do better but my personal experience is that that's about as good as it gets. There's been a couple 3.8 mileage threads but I couldn't locate them. IIRC guys were reporting between 12-22mpg. So really, I guess it all depends on your combination and state of tune. Big help, right?

 

[pontiacgp]

One thing that has been noted on another thread is the ethanol in the fuel drives down your fuel mileage. Back in the days of these cars gas was just gas. If you run synthetic fluids in the engine, transmission and diff that will help the fuel mileage

 

[YGspider]

To be honest I thnink my cutlass with the 3.8 is the most fuel efficent car I have ever drove. We own a 2002 buick century with the 3.1 and a gmc 1500 with the 5.3 and the cutlass feels like a hybrid lmfaoo. I fill that b*tch up every two weeks.

Once I do my GN engine swap I wonder if it will increase

 

[Erich]

Appreciate the replies, guys.

I know of about 4 stations around here that have ethanol-free gasoline,
but now that it's winter they have all swapped over to E10, what a bummer.

It will be on a mostly flat, straight road so hopefully that will help. I'll look into doing some fluid changes as well.

I hope this old turd makes it!

 

[YGspider]

Appreciate the replies, guys.

I know of about 4 stations around here that have ethanol-free gasoline,
but now that it's winter they have all swapped over to E10, what a bummer.

It will be on a mostly flat, straight road so hopefully that will help. I'll look into doing some fluid changes as well.

I hope this old turd makes it!

I did some roadtrips this summer in my Cutlass that kinda had me scared haha from Toronto to Quebec and the car ran better then I thought all I did was change the Oil and did some littel tune ups. the 3.8 will never die. Hell I was in the fast lane going about 130 Km's avarage.

 

[joesregalproject]

Appreciate the replies, guys.

I know of about 4 stations around here that have ethanol-free gasoline,
but now that it's winter they have all swapped over to E10, what a bummer.

It will be on a mostly flat, straight road so hopefully that will help. I'll look into doing some fluid changes as well.

I hope this old turd makes it!

I did some roadtrips this summer in my Cutlass that kinda had me scared haha from Toronto to Quebec and the car ran better then I thought all I did was change the Oil and did some littel tune ups. the 3.8 will never die. Hell I was in the fast lane going about 130 Km's avarage.

My 3.8 is the same, it's bulletproof. Leaks a little oil, but an 80s gm is supposed to leak a little oil. it's got a some get-up-and-go to it, for a V6.

 

[YGspider]

Appreciate the replies, guys.

I know of about 4 stations around here that have ethanol-free gasoline,
but now that it's winter they have all swapped over to E10, what a bummer.

It will be on a mostly flat, straight road so hopefully that will help. I'll look into doing some fluid changes as well.

I hope this old turd makes it!

I did some roadtrips this summer in my Cutlass that kinda had me scared haha from Toronto to Quebec and the car ran better then I thought all I did was change the Oil and did some littel tune ups. the 3.8 will never die. Hell I was in the fast lane going about 130 Km's avarage.

My 3.8 is the same, it's bulletproof. Leaks a little oil, but an 80s gm is supposed to leak a little oil. it's got a some get-up-and-go to it, for a V6.

Now now lets not joke about it having some get up-and-go to it. Its a slug no matter how I look at it. haha 110 Hp mabey 80 to the rear wheel haha