my stock 305 gets about 14-16 last time i checked. is that about right? some guys claim like 20 somethin, what is up with that?

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86 IROC-Z
40,000 miles!!
305 TPI
gutted maf/airbox
k&n filters
manual cooling fan switch
headers, no cat, cat back flowmaster
700R4 tranny
shift kit
manual converter switch
BF Goodrich radial TAs
3.23 gears
georgous car repainted by my dad and assembled by me

FASTER THAN YOU THINK FOR A "STOCK" 305 hehe.

 

I get almost US 30 mpg with my L98. But, I have invoked "Highway Mode" in my eprom. Before that, I got around 24 US mpg.

 

Check out my sig. More efficient engine works less so it gets better gas milage instead of lost heat into all the restrictions .

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

I took about a 3000 mile trip from St. Paul to Denver to Vegas and back - I avaraged just over 27 mpg. That includes some city driving in Denver and Vegas, and a lot of 75mph speed limits (which means about 85 mph highway speeds). Not too shabby.

Chad
'92 RS

 

pump to pump

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85 IROC 350 11:1keith blacks,.555lift erson roller cam,1.5 crane roller rockers,edelbrock intake,holley 4150 750dbl pumper, nitrous oxide,full length heddman headers,true dual exhaust, 11"stall converter, 700R4, 3.73 locker

 

I GET ABOUT 12- 13 IF... I KEEP MY FOOT OUT OF IT!!! and thats not very often!!

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89 firebird formula

356 10.5:1compression
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

 

so i should be doin better than 16 with my 305 shouldn't i?

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86 IROC-Z
40,000 miles!!
305 TPI
gutted maf/airbox
k&n filters
manual cooling fan switch
headers, no cat, cat back flowmaster
700R4 tranny
shift kit
manual converter switch
BF Goodrich radial TAs
3.23 gears
georgous car repainted by my dad and assembled by me

FASTER THAN YOU THINK FOR A "STOCK" 305 hehe.

 

I get about 18 city and up to 30 on the highway, before my tuneup I was getting about 10 city and 15 highway.

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'84 Z28 LG4 T-5
'92 Z28 wheels
153,000 miles
Front& rear suspension rebuild using MOOG parts
350 and WC coming in summer 2001
'70 nova 307, th350, all stock, 40,000 mi almost like new

 

18.8 average over last three tankfuls of oxygenated gas, commuting w/some freeway driving, heavy foot takeoff to speed limit, nonfunctioning TCC, intake gasket that lets oil leak into the right bank slightly fouling those plugs, 139k miles on engine. Mods in sig.

I'd think you should be getting better mileage. How new is your O2 sensor?

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, TBD heads, Hooker headers & y-pipe, 3" Catco cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

yeah the o2 is brand new and the MAF is ok too. should i check my timing? the plugs, wires, cap, rotor, have about 4,000 miles on them. the tps is new, and i just cleaned and rebuilt the throttle body and IAC valve. i have suspected that it may have a cam, it seems to fast to be a stock 305. i'm gonna time it and check the mileage when i get it back out. it'll run about 6.6-6.4 0-60. most penut cam 305 motors run about 7.5-7.0. is there any easy way to tell if i have a different cam? the only way i can think of is to take off one of the valve covers and measure the lift of the pushrod, or is that totally stupid?
thanks guys!

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86 IROC-Z
40,000 miles!!
305 TPI
gutted maf/airbox
k&n filters
manual cooling fan switch
headers, no cat, cat back flowmaster
700R4 tranny
shift kit
manual converter switch
BF Goodrich radial TAs
3.23 gears
georgous car repainted by my dad and assembled by me

FASTER THAN YOU THINK FOR A "STOCK" 305 hehe.

 

I'm rock stock L03 auto, 2.73 rear end and shot exhaust but otherwise excellent shape, getting about 20 MPG on 87 octane. Suprised me for sure, i was expecting to get like 10-15.

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88 Base Camaro
305 Auto
All Stock....for now

 

10-15mpg is for heavy trucks or wild 327+ build ups with no overdrive trans. Overdrive saves so much money.
Example: 10,000 miles a year at $1.80 a gallon. With 23 mpg you spend $780 dollars on gas. If no overdrive and no EFI you get say 15 mpg, that's $1200 in gas. You save almost $420 dollars in a year. Gotta love overdrive.

------------------
, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

i get about 12-14mpg avg on city and 13-15 avg on highway.(i have a TH-350)

whats wierd is that i got 19mpg on a 100 mile highway trip. Thats the most ive gotten in the last 2 years. most of the time when i go on long highway trips i get 13.9mpg. i dont get it

this is on a CFI 350 with no overdrive

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RED82TA5.7L

1982 Pontiac Trans Am
Cross-Fire Injected 5.7l V8
New TH350 Raptor with a shift-kit, 2600 stall torque converter, Eldebrock TES Headers, 3" Hooker Cat-Back.
Mods: 1.6 Proform Roller Rockers, electric fan, Corvette 5.7L computer chip, K&Ns, MSD 6A Ignition Box, MSD Conductor Spark Plug Wires .
Audio: JVC Kameleon CD deck, Jenson 4x6 front, Eclipes 6x9 rear, 2 10" mTx T4000 powered by a mTx 200watt amp.
Black Powder Coated 1990 16x8 Formula Wheels with 245/50/ZR16 Perelli P7000.
For Pictures go to
http://members.theglobe.com/RED82TA57L/mycar/


A cool Trans Am site with Message Boards http://www.transamgta.com

 

It usually takes a half tank to start my car and I have a fuel truck pace me as I drive.

 

I just bought an 86 IROC with 305 TPI and 700r4 auto. The previous owner told me he got between 14 and 16 on premium (93 octane) gas. I've been running chevron 93 octane and have been getting between 17.5 and 20.5 running around town and to work. Can't wait to take it on a road trip. My 81Z (350 4 spd) gets all of 12 to 14 around town and to work (of course I run it harder as I;ve owned it longer and feel more confident in pushing it harder).

------------------
Z's r Best

 

I have 100,000 miles of experience with my 305 powered Trans Am. Around town, I always got 16 MPG, and 20.5 MPG on the highway.

Then, I built up the 305 engine. Now, I get 14 MPG around town, and 21MPG on the highway. Plus, I get down the dragstrip in 14 seconds flat at right about 100MPH.



------------------
Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.