How many mpg will my 305tbi get with a 700R4 w/shift kit and Dynomax super turbo cat back exhaust?

 

I'm getting about 17, but none of that is highway mileage

 

What is your gearing? Mine with 2:73 gears and the same mods you have averages about 15-17 around town. About 23-24 on the highway, depending on if I run the A/C.

 

Mine are 2:73 also, I don't have a shift kit but I don't have an open element air cleaner with an aftermarket muffler

 

Most I ever got was 27 MPG that's it if its running good. Trans not slipping etc.

 

Wow, what did you replace to get that kind of MPG? that's great

 

Before i pulled my 80,000 mile lo3 it got around 17-20 mpg with 3:23 gears 700R4. That was with me keeping my foot in it pretty much all the time.

 

Mine has 87,000, but I usually only make 3-10 mile trips, nothing longer than that except maybe 2 times a month I'll go on a long drive, so 17 sounds about right with no highway miles, but 27 MPG, that's great

 

87,000 is that all? Mine has almost 208,000. 27 MPG isn't too hard. Just a good tune up, exhaust, open element air cleaner helps. Like I said before, running the A/C makes a few MPG difference. If you wanted to be a stickler, you could install headlight covers for better aerodynamics. Might be worth it for long distance highway driving but I doubt cruising around town would help any.

 

Yup, only 87,000, I have an open element and an after market muffler with 2 1/2 tailpipes, I don't really care about my MPG, im just saying that 27 is really good, and with 208,000 miles, you've deffinetly kept yours in good shape

 

A stock rated t-stat will help mpg over the 180/160 stats that everyone seems to have.

 

I was getting 27 basically bone stock, with aftermarket cat, 2 3/4 exhaust, into flowmaster 80 series. No aggressive driving. That was highway. Around town was low 20s, now I get 18 trying to save fuel

 

I know that with the 700R4 you can still manually shift into 3rd which helps with fuel consumption around town, and I do plan on installing an open air filiment and getting a tune up soon. Not an agressive driver, and the rear gears are stock 2.73s, A/C doesn't work so that makes that simple (Thank God For Oversized Windows!), I also am going to finish redoing the exhaust in the next couple of months, so 24 Highway and 17-20ish city sounds about right.

 

stock. 305tbis are quite good on fuel mileage. I do miss that about mine. but oh well....

 

magnaflow catback, shorty headers and ypipe with no cat. ultimate tbi mods, 180 therm, 3.23 gears and 700r4. egr delete and a stage two tbi chip i get around 24 mpg cruising 70 to 80. 126000 miles on here.

 

125xxx miles 305tbi w/700r4 w/2.73s I can get around 20something in town and 29-31 highway

Just basic tuneup stuff- Plugs, wires, open element, AIR delete, aftermarket muffler

 

I def. want to get an open air filiment. And engine tune up. Good to know this thing is that efficiant.

 

Would the A/C delete pulley help any by reducing drag on the belt
or is it a mute Q since the A/C free wheels any way?
Just a thought

 

A little different, mine has a T5. When it was in stock form it pushed near 30 mpg on one trip from Southern Oregon to Western Washington. Since then, the rear has gone from 3.08 to 3.23 to 3.73, added headers and open element and still averaged about 20 mpg mixed driving. TBI motors are quite fuel efficient.

 

Very very nice, and that is mpg in the passific NW with hills and curves. That is a very nice drive, though I find small Oregan towns to be creepy. I live in Texas, great muscle car country with the flat and straight wide open roads, no handling necicary, just raw power. I still miss Washington though. I wonder how the heat will affect mpg.

 

I was getting 22 MPG with 3.42 gears about 6 months ago.

 

22 hwy or 22 avrg?

 

highway not bad though!

 

haha, well I'm going to college is spring, so I think I'll stick with the 2.72s for now and save some cash haha. Every penny counts right?

 

Skelitor I know this is old but I have a 91 RS with a transplanted 350 under the TPI. Now this is a 93-94 truck engine so I am assuming a low compression engine is there, but I have all the 350 equipement on it now. I am in Kansas City, I drove out to Ft. Riley and back at speeds of 80 and a little faster just to see.... and I averaged 22.3 and that included about 50 miles of in town and some 13 year old training miles... I am getting 21 around town. Now next spring/summer we will see what the newly rebuilt Vortec will do. I also have the stock lo3 exhaust on it, so I am sure it is way choked.... My son and I have some work to do this winter.

 

I'm currently getting around 20. I have around a half tank left (these fuel gauges aren't very accurate) and 175 on the trip meter. It should be higher but for a while I drove it with a horribly gummed up air filter and stock intake.

If you can pull some gears for like $50, it would be a good idea to change them out. As someone else said, your in-town mpg will probably go up with a 3.23 or 3.42 gear swap. As for highway, you can always just slow down and hit cruise lol

 

i just pulled a tb 305 out of my 91 formula i was getting 182 miles a tank full combined driving.....something was up..............got a 355 going in

 

yeah that is horrible mileage if true!

 

i have a 88 chevy stepside, that gets 15 city with a 350 tbi pushin 400 horse and 3.42 gears. somethings wrong if my heavy truck is getting almost the same mileage

 

I want a 400 horse 350 that gets 15 mpg!

 

thats mine -___- minus 150hp..

 

You didn't ask but I had a t5 before I started my project and stictly interstate driving I have gotten 30mpg many times.

 

i also drive like an old man most of the time =)

 

Pfft, easily done if you run a crappy carb'd setup. 20 easy with TBI and EBL

I think I should be able to put 300 to the wheels (pretty damn close to 400fwhp) if I end up getting some Vortec heads. Especially since I saw that Lunati 343hp/356lb-ft 305 build using ported lg4 stock heads

 

Shut Yo face Ron. We all know your doing a crazy 305 build. Always manages to sneak it in there...

I'd like to see your mpg after all the mods highway and city. Are you planning on getting a new rear end/rear end gears? Going posi?

 

You got me, I'm an attention *****

But I really had intended to do a mild 305 build, but then I realized that money grows on trees and deals are hidden under rocks, and so began the madness.

I'm planning on going 3.42 with positrac, but someone I know just totaled his Fox mustang so I'll see what kind of rearend he has, and if I can snag it for a good price

 

well i bet he is getting 20 mpg but he doesnt have 400 HP.

 

i used an lt1 cam, 1.6 springs. new rollers and rockers. tbi spacer, injector spacer, powercharger, underdrive pulleys, lt exhaust, forged bottom end that i got from a friend for free haha, and other goodies, just didnt have enought cash for the vortec heads at that time

 

ok so you dont have 400 horsepower it is proven now

 

close but about 35 under

 

That's still about 300 at the wheels, assuming a parasitic 20% loss and puts you around at least 1 hp per cubic inch. Not at all bad for a budget build

 

with stock heads and no tune I dont see it. most of those mods dont really do anything I know I did them. cant take a 210 hp engine slap a cam and headers and make almost 400 without heads and without tuning it would not run close to 100% i know because I have done it

 

I wouldn't consider about 365 to be almost 400.. I'd consider it to be a little over 350

 

Yeah Ron. I only put close because that is what tyler said. Then he says 365. in that case cant take the stock engine, put a cam and headers on it and be a lil over 350 hp. there

 

I had a 355 with an edelbrock 600cfm on it and an auto trans and got 27mpg on highway trips. On the flip side I have a TBI 305 5 speed and I get a bit closer to 30 on the same trips.

 

that was suppose to be a 2 but same kinda deal, its mid between 360 and 380. couldnt get a consist run plus it is my DD so i wasnt being to harsh on it. and it was tuned, found that on craigslist also it was called intimadator stage 4 chip and it comes with a little tuner thingy that you can change certain things and almost like set different modes, for towing or highway, city etc.

 

Why have a 400hp 350 getting 15mpg when I can just give you my 170hp 305 getting 15 mpg haha I gotta get that figured out

 

For anyone who wants a hell of a deal on a built 350 engine- Throw TBI and Gen 1 manifold manifold and you'll be good to go (that's just awesome, Vortec adapted to accept standard intake manifolds). Probably 18-20 mpg right there...

I'd be getting this if I had the money, but alas, it does take time for my money tree to grow, so I'll stick to my 305 like I promised myself I would

http://washingtondc.craigslist.org/m...680641491.html

 

tbi gets better mpg than tpi? how big is difference 305tbi vs 350tbi?

 

Heck my 350 gets better mpg than my.old 305. With my ebl leane cruse i get 28hiway/12street on my 350