In the past I've been enjoying about 17 MPG out of my TPI setup 305. I do have the nicer gears (3.45 BW 9 bolt) however, it should be above this by a good deal in economy. I finally tuned it up, and changed the o2 sensor and so far, it seems like I'll hit 20 or 21!

But... alas, I'm addicted to power, and have been considering swapping to a carb intake and 4 barrel. What I Want from you guys is this:

What kind of mileage do you get out of your carbed cars. I drive mine pretty rough, but I've never seen the milage really change. What is an estimate for mileage if I swapped to say, a dual plane edelbrock? I want some ideas here.. I know a carb can be well tuned to give like 22 mpg (seen it done on a monte SS) but.. I'm curious as to what I'll see in reality

Any notes would be really appreciated.

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"I put my 42 sticker on the
back so other cars can see
it...."

 

This ought to start a good ol' fashioned shootin' war.

I'm getting 19 mpg when I commute and spend Friday evening at the track, 21 when I commute but haven't been running the 1320. I'm not heavily modified and don't run 13's, but it does well in the stoplight wars. My TCC doesn't lock up (still need to spend some time troubleshooting that) which doesn't help my mileage.

I don't really baby it to get that 21, by the way.

The winter project is to get the LB9 I picked up ready to install w/ZZ3 cam, World 305 heads, ported plenum and gasket-matched intake, TES or similar, high flow cat, and better catback. This to improve the 16's I'm running at Bandimere while preserving the 21 mpg I'm getting now and being able to pass a dyno emissions test. You're going the opposite way I'm going. But, it's a free country.

If you have to pass emissions, or might have to in the near future, you can't do it with a carbed '89. Spend you money improving what you've got, and you'll get both the speed you need and the mpg you want.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 3.08 open, cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress.
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

[This message has been edited by five7kid (edited August 01, 2000).]

 

Don't do it...or we'll be reading posts from next Spring on how the choke on that POS carb is sticking and...

But seriously, do you want to go back to the days when you had to pump the gas pedal three times, or was it four? Then let the car warm up so you can even drive it (it's winter in my scenario and -20 if really want to know).

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Mike

'90 IROC, 5-speed, ZZ4, & Trick Flows
~~~~~~~~~~~~~~~~~~~~~~~

 

I wouldn't be surprised if you dropped back to the 17mpg you were getting before. You can easily get 20ish but realistically you're likely to get 17-18ish. Seems like the average. That is approx what I get but I drive around w/ my foot in it most of the time so I don't even bother to compute mileage very often.

I switched from TPI to carb BTW. No regrets. Only affordable option for me when I was dropping in a built 350. The stock TPI woulda been giving me headaches for years, and the upgrade prices ain't cheap.

BTW, my car passes the new dyno emisions test here w/ the 3" Catco cat as the only emisions equipment on the car, no EGR, no small carb (750 vac sec Holley), and no detuning. If fact it passed w/ ease. And they didn't know it was a 350 so I assume it was under the original 305 TPIs max test numbers. Unless your dyno test is muchhhh stricter than mine here, you shouldn't have a problem w/ a new cat and a tuned up engine.

Anyway...

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

[This message has been edited by Ray87Z (edited August 01, 2000).]