Guys, i was wondering what anybody with 300+RWHP was getting for gas milage?
Well meaning with a 350TPI or greater, maybe 383 or whatever.

Let me know guys!

Also, your setups would be helpful also
list of mods.. etc..

 

20 MAX 16 on street.

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89 FORMULA 350 Edelbrock Cat-Back ,March Pulleys,Super Coil,MSD 6AL ,Edelbrock TES's, AFPR ,Shiftkit, Edelbrock Base

 

mine gets 16 mpg. No matter how i drive.

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87z 383,afr 190's, crane hyd roller(224/230-.509/.528,112 sep),Ported and polished mini ram, 24lb inj, 3.42 gears, strange 12 bolt, tremec 5spd, , 1,3/4" slp headers.(stock 305 hypercrap chip), other stealth goodies.
Runs 14's all day long.

 

Wow, that really isn't too shabby then considering my old tired 305TBI motor in my 91RS gets about 20-21highway and 17-18city...
Of course that doesn't really say much for that motor. I think the previous owners didn't know what car maintenance was.

 

15-16 on the street and 20-22 on the highway.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

what kind of mileage would a 400 sbc get with a TPI setup? I see that some of you are using 350s and 383s, and the mileage is not that far off of the 305. would the mileage of a 400 be like pouring gas on the ground in idle?

 

city 12, highway 20

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTB, ported plenum, 52 TB, MSD 6AL, TPIS level V prom, Mod .MAF, Superior shift-kit and some minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

 

Mine is relatively stock and gets 16 city, and 22 highway. My brother's 92 RS 305TBI/auto used to get 28-30 on the highway. Now that it has 3.73's, it gets about 25.

89 Transam GTA, a few bolt ons

 

Mine is not TPI, but I get 22 on the highway with the mods listed below.

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'83 Trans Am. 400 CID, 224/234 crane cam, Summit aluminum roller rockers, hand ported intake, home bored 2.09" (53mm) throttle bodies, MSD 454 injectors(75 lb/hr), Holley 255LPH fuel pump, custum modded FPR w/Vacuum port added, Edelbrock TES headers, empty cat, SLP 3" stainless steel cat back, stock ECM & chip. Borg/Warner T-5 World Class, 12" Corvette rotors and clipers, GTA 16" wheels, South Side Machine subframe connectors, 1LE sway bars, 3.45 ring and pinion, Alpine sound.

 

POOR!!! Find out RWHP tomorrow.

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Bob '89 Formula CC350
Last(lost)Member of the Elusive Great Lakes Crew
My car's homepage

 

hey Tom, how does the 400 preform in your car? do you have any problems with the amount of horsepower in city conditions?

also what kind of power do you think you are pulling with that setup?

 

I'm getting 27mpg on the hwy and around 20mpg around town and i'm pushing about 330hp with my 305TPI and Auto.

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88'TA 305TPI 330HP, NATURALLY ASPIRATED, PASSES N.J. EMMISIONS. "I AM JUST THAT GOOD"

 

Damn, that's not bad even for a 305. Before the mods my IROC got 15 city / 20 hwy. After the mods the last time I checked it got 18mpg w/ mostly highway driving.



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224
.495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\
Flowmaster catback Coming Soon (?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 160,000 miles, K&N filter