ok im thinkin of buyin a tuned port car just for a daily driver in addition to my street beast. My question is for a stock or basically stock(slightly modded) tpi 305 or 350 what milage are u getting? I need to know what year, model, engine, tranny, rear your running and if any mods. Again this is for stock or just about stock motors. thanks for your input i appreaciate it.

 

go to www.fueleconomy.gov

it'll give all the fuel economy info you need on stock engines

 

thanks pal

 

Real world results. 88 with L98 and 700R4, mostly stock with recent tune and injectors. 80 mile daily commute 90% highway driving at 60 mph I get right at 24 mpg average on many tanks of gas. Use credit card and write down the mileage, get a handful of receipts and figure it up every couple months. Last batch was 24.3 mpg. Not bad for a real car/engine. (edit) This car doesn't like regular gas in hot weather though, at least 89 octane needed. Premium is best for full throttle to quiet it down.

 

I have owned my 1989 GTA with a TPI 5.0 liter 5 speed since it was new. Before I modified the engine/exhaust system I got approximatey 23 mpg in the city and once on the highway between 29 to 30 mpg. This is driving at the speed limit in 5th gear on the highway. Also, we have larger gallons, I believe, in Canada. Hope this helps.

 

The highest that I got before I modified mine was 24.7mpg. I was driving back from Houston to Dallas and was keeping my foot out of the throttle whenever possible (like getting on the highway, probably looked like some old man) and then using cruise control the rest of the time.

dk

 

On highway trips, the TPI 305 in my '88 SS will average 20-22 mpg with 3.73s and the T5. However, I don't drive exactly "sanely." I'm sure if I kept it to 65 and didn't blast out of every toll plaza on the GSP like John Force I'd get 24-25 mpg.

 

so all in all these cars get decent milage right

 

My car has never even close came to that kind of mileage, Had it tune recently- got arround 17mpg on the freeway. Before that for years only between 14-15 mpg mixed driving;and I keep it in a good state of tune. Everything has been replaced recently(over the past two years) only thing that has not ever been replaced in the last decade is the air check valves for the emmissions, if this could have that big of impact? I don't know - no one ever has mentioned them on this board as a major replacement item. on my Ls1 a bad aircheck valve will immediately set a code. So my mileage usually sucks overall+ with crappy california gas. If I could get 20mpg mixed driving I would jump for joy(Almost- San diego has the highest gas prices next to hawaii- total sun tax)

 

Oh yeah, my car is not stock-But even when it was near stock never bested 16mpg