I only drive it occasionally and can afford the gas I need/use in my 76 L48. I just get po'd at the fuel companies for taking advantage of the end users. Us. I understand switching to a true dual exhaust will gain a few mpg's. What else can come into play here without tranny changes such as a 200r4 that wont kill a wallet in the process?

 

Truth is, a transmission change (while it may hurt now) will pay for itself and then some in less than three years.

Some quick calcs:
Assuming you drive 20mi a day every day at 10mpg, with fuel prices being what they are here (Northern California, $3.25/gal for 91), you'll spend just a shade under $3000/year on fuel.

Take that same 20mi per day every day at 19MPG, like you'd get with a TKO setup, and keeping the fuel prices constant at $3.25/gal, you'll spend about $1250/year on fuel. A savings of about $1700/year.

And if you consider that a Keisler TKO kit is about $4500 for the parts (and you install it), then you've just saved a MESS of money in the long-run.
Even if you have a shop install it for, say, $1000, you've still gotten it to pay for itself in three years.
As I've learned from certain members in the VW crowd: "Do it right. Cry once."


Outside of trans swaps, you could switch to some kind of FI, but again, if you want to do it right (aftermarket) you'll need to spend a pretty serious amount of money.
Exhausts are a good way to go too.
You could stuff a different rear end in there as well...

Oh well, point is, there's never really a cheap, easy and reliable solution.
Fast,
Cheap,
Reliable,
Pick two.

You get the point.


Oh wait, I did forget to mention the FREE alternative for fuel consumption issues... WEIGHT! Remove everything from your car. Take the T-Tops off, become anorexic, never run around with more than half a tank of gas, remove all the carpet, your passenger seat, etc.

Won't be pretty but it'll work.

 

If most of your milage is on the interstate then the trans change will help if not then you might want to work on the carb.

 

Rear diff. gear ratio.

 

my 4spd 76(in78) went from 13 to 17.6 just by changing to 73 stock dual exhaust w/ turbo mufflers

 

Duals, low restriction mufflers
Headers
Comp says the 260H cam can increase mileage. Good for about 300+ HP. L-48 needs more cam.
There are the obvious like keep tuned, tire pressure, avoid excess idling (0 mpg) ...
It has been said that an old carb 350 Impala can get 30 mpg at about 30 mph.

 

When I got my mechanically totally stock '72, it got about 12-13 mpg, and without today's wide band O2 sensors available, let alone know about them as a tuning aid....I put on DPFI, a stock TPI system, speed density, bolted on the stock L48 engine, muncie, 336 rear, the car jumped to 24 on the freeways, and about 18-19 mixed bag....

later on I went to overdrive auto it being cheeeeeepest way, my problem was I also replaced the engine with a roller 355 engine, and hotrod cam ZZ9 from TPIS, my economy suffered tremendously, it's only about 20 mpg on freeways now....with the o/drive....

power costs money....

 

Don't know how good you are with mechanical skills etc., but you could consider finding a TPI unit and using a programmable ecu like megasquirt.
TPI's come real cheap today.

 

TPI did come to mind. I have average mechanical skills so the technical portion would definitely become the learning experience. I'll start with the dual exhaust. Not inexpensive but something that was on my to do list anyway. Time to study up and use the search button for TPI to see if I will take that route

 

Check out Matt Grubers site,he has some interesting ideas.
http://community-2.webtv.net/MATTGRU/carb/

 

TPI would be a good addition. I recently posted again my "install primer". Look at my username and TPI swap. TPI parts have dropped in price in the last few years. Really FI and transmission swap is the fastest way to any significant mileage improvement. For a basically stock engine, TPI is a real wake up, if you want more than about 400 hp or want to go over 5500 rpm or so it gets expensive and/or impractical.

 

Also look at taller tires in the back end, this will effectively drop your final drive ratio.

 

I thought you said it was blocking your egr. or was it the plywood carb spacer? You must be getting Pruis-like milage now.

 

Today 07:40 PM
pbcanney Quote:
Originally Posted by Matt Gruber
my 4spd 76(in78) went from 13 to 17.6 just by changing to 73 stock dual exhaust w/ turbo mufflers

I thought you said it was blocking your egr. or was it the plywood carb spacer? You must be getting Pruis-like milage now.

 

Here is the link to the thread I posted on the TPI swap I did last January.

http://forums.corvetteforum.com/show....php?t=1580191

I don't drive on the highway that much, it is mostly city driving. I am getting an average around 16.5 mpg, My best has been just over 18mpg, and a worst of just under 14 (spirited driving).

 

My '69 with TPI I get about 18 city and 21 highway with 3.7 gears and 700R4 transmission.

 

my 76 was sold in 1982