I really don't pay attention to that type of stuff maybe i should , but what type of mileage do you get on yer cars. Normal everyday drivin and 4th gear the whole way Highway drivin??

 

Ive been getting around 24-25 MPG, 360-375 miles to the tank, in my new-to-me 1989 Formula 350. My GTA gets about 20-23, 310-355 miles, but the GTA's got a 383 ( HOT cam, TPIS intake....etc.) Of course, thats taking it EASY and on the highway.....

Kevin

 

My best is 20 on my GTA. I drive pretty hard though (And the 3.27 rear doesn't help any).

------------------
~3.1EyeCandy~
"The car that started my craze" -'92 Firebird 3.1 (A car sold)

My new baby: '87 flame red GTA 350 w'auto, ported and polished plenum, custom cold-air intake w/K&N, Hooker SuperComp Exhaust, Splitfire plugs, Hypertech Airfoil,
Carmine interior with pioneer all around
THE GTA

 

18 around town, 22 on the highway.

------------------
Black 88 GTA L98
271 RWHP, 344 RWTQ
13.406 @ 103.72 MPH
ZZ4 bottom end, Edelbrock 6085 heads, LT4 HOT cam, GMPP 1.6 RR's, ported stock TPI, SLP 1 3/4" headers, no cat, Dynomax cat-back, Custom PROM (by me), in desperate need of stall converter
E.T.F.A Treasurer

 

i get about 15 mpg thats around town and drivin to work 25miles round trip 5 days aweek about 180-200 per tank how do u guys get such good mileage with a 5.7?

------------------
white/gold GTA ,leather new 355TPI ,S/R torker 2.02 1.60heads comp cam 212in 218ex 112lobe sep. dur. .488in .495ex lift. edelbrock headers ,dyno 2000 says 337 hp 405ft lbs of tork..TCI streetfighter 700r4 3:27posi twin cats,3"catback,aluminum d.shaft ported plennum,afpr,8mmwires,k&Nand all other "free" mods, performance resource chip,SLP cold air intake.

 

18 city and 25 highway

-P

------------------
Pontiac Trans Am GTA'89

CC1 GW6 G80 JG1 L98 MXO N64 WS6 822

mods: firebird '89 four spoke steering wheel and i'm still not running low 13's yet!

 

If I can get 210 miles out of a tank of 93, then it's a miracle.


---------------------------------------------
1989 Formula 350

 

I'm with you formula8! I normall fill up at 200 even.

 

hmm. 13 MPG and going down. used to get 16, then 15, then 14.5 for a long while. now its 13... i think something is wrong.

------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake

http://www.geocities.com/david_angel_16

 

I have an '89 GTA/ASC Ragtop.. lately I got about 23 on the highway, but that was 2 weeks before the tranny blew up, and hasnt had a tune-up in forever. That's with the 3.27 axle, K+N Cone filter, and TB airfoil.

I can definitley see these cars getting 25+ on the highway. Im installing a new tranny, MSD6a, and doing a tuneup over the winter. I'll see how it does in the spring

 

20 city 26 highway

 

18-city
23-24 highway....

I am always the first off of the line.... that is my driving mentality, with the Formula.....

------------------
http://kiztope.50megs.com
92 Pontiac Firebird Formula WS6 5.7/A4
K&N, Blue Streak Cap and Rotor, strange unknown exhaust system (sounds good though)...
Mods are in direct proportion to income!

92 Rs 3.1/T-5
Beautiful car, many mods, but now I am turning attention to the 'bird!

AIM : Theonekiztope
ICQ: 8787542

"Maybe one day life will take a turn. When it does Lean into it!" Leon Calrinsky (98)

 

YES!

210 to a tank is nothing short of a miracle! How DO you get such good mileage outta the L98?

------------------
1989 Chevrolet Camaro IROC-Z
L98 - 350c.i. TPI, rebuilt 700R4 auto w/shift kit, Dual catalyst Monza PaceSetter Cat-Back, SLP 1 5/8 Coated Headers, 3.23 Posi rear, Hypertech Thermomaster chip with 160stat, MSD 6A, March Under-Drive pulleys, AFPR, K&N's, !Air Box w/ Ram Air, moddified MAF, !TB Coolant, Spohn Dual Cat SubFrame Connectors, Alarm, Keyless entry, remote starter, 92 Z28 AeroWing, Brand New Paint (6/21/01)

Future: ZZ4 TPI w/EGR, T56, 3.42 or 3.73, Spohn strut tower brace and LCA's, Accell Universal 24# injectors

More info and pics on my webpage:http://go.to/iroc-z

AOL IMer: GPA 0point0

 

Yeah how do you get such good mileage i get maybe 15 MPG. Maybe it's the gas we have in IL.

------------------
89 Formula WS6 w/ TPI 350
MSD blaster coil and 8.5 mm MSD's
K&N filter

 

If you're not well into the 20 mpg highway range in ANY V8 f-body, then something is wrong, period.
-Don't neglect your basics like filters, plugs, wires, cap/rotor, etc.
-If the O2 sensor is old, it might still work, but be a little slow to react. This costs some fuel.
-Simple stuff like the timing being set incorrectly will cost mileage
-make sure the torque converter clutch is locking up, this is also a few mpg easy on the highway.
-Stuck/dirty injectors can cost efficiency and thus mileage. Further, say that the passenger side has a seriously over-rich running cylinder, the O2 would never even see it and thus you're wasting all that gas.
-Any of the sensors on the engine could be skewing the ECM making it not do what it is supposed to be doing

In other words, if you're getting very poor mileage your first priority should be figuring out why and fixing it. If you can't get the best gas mileage out of your car, i am sure it isn't performing how it should be either.

------------------
Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
305 TPI A4 2.73 - 14.7 @ 93.6
Stock except ported plenum and dual cats
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

i get 12 in town, but that is racing everything in sight. that is why i have a 355. to drive it. i get 18 on the highway. but that was with old plugs. havent figgured it out with the new ones.

------------------
My Ride:
1987 IROC-Z 355 TPI
2.73 posi
K&N air filters
polyurithane front and rear anti-roll bar bushings
3 inch exaust
DF88ECU pannasonic cd player head unit
soundstream audio 200w amp
JL audio 12" subwoofer
pioneer 6x9 rear speakers
KILLS:
89 mustaing GT
97 civic type R
96 s-10 SS
94 integra type R
98 cavalier (this guy must have been high, it was a 4 cyl.)
89 caprice
90 camaro RS 305 tpi
95 mistubishi 3000 gt VR4
many more slow stupid cars.

[This message has been edited by @ZZKKER (edited November 21, 2001).]

 

I have to agree with Ed, as I have slowly been replacing everything in the car (fluids, suspension, ign is next) my MPG has been going up so I have slow been "restoring" my car back to normal.

Just a front end alignment netted me 2mpg easy.

Next up full MSD ign setup cap/rotor/ign/wires and plat plugs, all the **** is original no doubt or replaced by grace of *** once maybe.

It's good to know I have excellent mileage to shot for!!

------------------
1989 Trans Am GTA, Gutted air box, K&N, Koni Sports

 

My brand new, unmodified 91 Z28 5.7 got 18mpg around town and about 22/25 on the highway.
My 92 Z28convt with 305 and 5spd, hollow cat gets right at 29mpg highway

------------------
Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

My pretty much stock L98 is getting around 18 city and 22 to 23 highway!

And thats with 195,000 + miles on the motor.

she's getting a rebuild and supercharger soon!

[This message has been edited by poorboy8 (edited November 26, 2001).]

 

With OD i can usually get 24-27 MPG on the highway, while around town it goes down to about 17 or so MPG in my vette. Note thats when i'm not driving that hard...when i have a heavy right foot, it goes down accordingly.

------------------
Red '87Formula Firebird
-mostly stock 5.0L LG4 w/cowl induction setup borrowed from '83 TA and T5 tranny.

My newest Ride:

'85 Silver L98 Corvette w/4+3 manual tranny. not bad for $3500.

 

My 355 gets around 24 mpg on highway and 18 in town. Alot better than the original 305 that was in it. But I also have replaced darn near everything on the car.

------------------
1992 Camaro Z-28 custom 25th anniversary, 5.7 TPI auto, 2.73 posi, t-tops, arctic white with 92' medium mettalic gray stripes with black border stripe.

1967 Pontiac Catalina 2 door fastback, 400 v-8, auto, cameo white, dark red interior

1987 Olds Cutlass, 350 Rocket, auto, dark gray/light gray interior

 

I drive very aggressively and combined city/highway is around 17-19 mpg. I get about 190 miles to a tank.

I like to get on the throttle up to the speed limit then cruise about 5 over. My MPG definitely suffers due to my driving habits.

I do lockup my converter manually on the highway on long hauls. It seems to make a difference. I have gotten 230 miles to a tank on a long trip.


------------------
Mike L.


1987 IROC Z 5.7 TPI A4 3.27 Borg-Warner
four wheel disc

Mods:[i] 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, MSD 6A, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler,cutout. 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog, few others I forgot...???

**BOYCOTT LAPEER DRAGWAY**

 

well my bone stock 115k GTA with a 700R4 with 3.23's
has given me the best of 275 per tank. i gained 4mpg with just the change of the 02 sensor.

 

I get about 14-17 City & 24-26 Hwy with the t-tops off.

Jay

------------------
My 1989 Trans Am-Origional 5.7L TPI, 4-Wheel Discs, 16" Diamond Spoke Rims, T-Tops.A very rare car. See my Window Sticker
1995 GMC Sonoma Window Sticker
Friends DON'T let friends drive rice
Kills:94 Talon TSi AWD, 94 5.0L Mustang GT, 2000 Xtreme 4.3L, 93 Talon,87 Buick T-Type 3.8L SPFI Turbo
Member WWW.TRANSAMGTA.COM

 

I usually get 150-170 miles with 1/4 tank left. But I go full throttle most of the time. I don't think there is ever a day I don't do 90+ mph or mash it hard off of every corner.

 

Okay, I don't feel as good about myself now. When I first bought my 305 TPI Trans Am it got 17 to 18 mpg. City vs. Highway didn't really matter much, it was always between 16 and 19.

When I finished putting in a new ignition, regapping the plugs, new wires, cap, rotor, the works, and adding a new exhaust system with 1 3/4" headers (The headers have definitely cost some low end, but i'll need them for my new motor), and a 3 inch exhaust, I've gotten it now to where it will get 18-19 around town and about 21 on the highway. I thought that was spectacular until I read this thread.

Am I way below where I should be? Should I see more like 25 or 26 highway? As i've said before, ignition is all new, timing and fuel pressure are properly set. The car had 90k on it when I bought it, and it now as 115k. The engine is still airtight. No leaks, drips, rattles, or knocks of any kind.

I was expecting that my gas mileage would plummet to 15 or so when I went in the 350. Can I really expect a lot better than that?

------------------
86 Trans Am WS6

It takes some ***** to do your quarter-miling on foot.
Recent ET's:
@Atlanta 50.80
@Southeastern 50.62
@Mtn Laurel 50.04
Future mods: More endurance workouts and some 300 meter repeats. Projected E.T., 49.8

 

I get 19 mpg in town. Never recorded highway though. The one time i actually drove on the highway (interstate) @ 70 mph i stopped at the gas station filled it up and hit the reset button. Heh...I know it was up in the 300's for that tank of gas.

------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR
-Gutted Air Boxes

 

I get about 14 MPG if I'm lucky for just driving around town. And for longer highway trip around 22 MPG or so. Not the greatest, but I didn't buy the car for fuel economy!



------------------
1987 Camaro IROC-Z
350 TPI (L98), HyperTech Airfoil, K&N Filters and modified airboxes, AC Delco RapidFires, Taylor SpiroPro 8mm wires, Energy Suspension polyurethane bushings for front and rear LCAs and sway bars, KYB struts and shocks, BFG g-Force Z-rated tires, MAC STB, MAC SFCs, JET low temp stat, CarSound Hi-flow Cat, 3" Mandrel-bent pipes, Flowmaster muffler, Corvette Servo, TransGo Shift Kit, Corvette 2000 Stall, TruCool LPD tranny cooler, T-tops.

2001 Sunfire GT
2.4L, 5-speed, K&N cone filter, interior detailing, 200W Monsoon Sound System (8 speakers), Silver Metallic exterior with grey interior.

Web: http://www.angelfire.com/on3/whitelightening

 

That doesn't sound too bad. How you drive affects your gas mileage. It also is dependent upon the accuracy of the information the computer is getting. A bad 02 sensor or CTS can cause your motor to drink gas.

------------------
'87 Red Formula Firebird
-mostly stock LG4 w/cowl induction setup borrowed from '83 TA and T5 tranny

'85 Corvette
-stock L98/4+3 manual tranny
-z51 package

 

i wish i could get 15 to 20 around town my car averages about 9 mpg around town and about 17 on long trips i have had it on 3 different machines looking for a problem and everything comes up clean i know my fuel pressure is a little above factory and the bigger injectors will use a little more fuel but not this much!!

------------------
Black 89 5.7 355 cu
Performance transmissions 700R4
black and flamed to the taillights, much much more....