I drove from SF Bay area to LA and back this week. It was the first extended drive I've taken in the Firebird and I was anxious to see how the engine performed with a recent tune up, cooling system flush, transmission service, etc.

On the way there, I kept the speedometer lower than 80 MPH with the RPM's not exceeding 2200. I-5 in the central valley is a straight, flat, BORING peice of road that I am sure allowed me to get maximum economy. Entering LA on this interstate there was a few hill climbs but then it entered the tangled mess that is the city.

22 MPG - I was hoping for more like 26 but I am guessing the this reason for the decrease was likely my PROM. The stock chip would not have been throwing as much fuel like methinks.

On the way home, lets just say that the Valentine One detector is worth its wieght in gold. I averaged 85-90 on the flat part of I-5 and peaked at 120 once to see whatit felt like. I don't recommend it in a convertible but it sure breaks the monontony.

Overall, I was (am still am) happy with my TBI.

 

this is un TBI related but me and the Wife just drove up and down all over california in March for our aniversary.

Have you driven on route 1 just above San Francisco...HOLY MONKEY BRAINS..scary! In a convertible terrifying for an old lady driver like me. Every turn is make it or die.

Beautifull state the more north you go me thinks.

excuse me for being off topic.

 

A. i did the trip from Phoenix to Riverside, CA on one tank of gas, 360 somethin miles, 11 gals when i filled up... 30+ mpg w/ a 350tbi
B. My convertible top has been close to 140mph and it looks it... lol, quite scary, it gets really LOUD... its fun with the top down, but scarier...

 

You burn your own chips, right? That was right on the speed limit and FLAT too, no?

 

Cadillac, how many miles are on your TBI?

If I ever take my TBI long distances, the most i'm worried about is reliability, breaking down in the middle of I-5 with nothing around. I know these things get great MPG, and it's the least of my worries.

Also, was that 22 MPG with the A/C on? Because I don't know how you could drive down here where it's about 98* F give or take, without the A/C on.

 

i have a TBIchips.com chip, 3.23 posi rearend, not so much flat... there is a little bit of a mountain range in the middle, at points you go from 800ft to 4600ft... and lol.. no it was well above the speed limit... driving 4 hours when you start @ 12am seems to just go by quickly... lol... i made the trip, all 360+ miles in 4 hours and 15 minutes... lol, i was FLYING... if you avg that, my avg speed was 85mph...

 

Odometer reads 175K, engine has around 55K from what I can tell. The thought of breaking down on I-5 is a scarey thought for sure. Nowheresville! Still, I have every confidence in a well maintained Chevy SB.

SchwarzCamaroRS, we may have the same chip but I really need your rear end (and possibly another 45 CID). I almost don't believe 30 MPG.

 

your 2.73 is better for mileage than my 3.23... and i use 55lb/hr injectors.. not the 22lb/hrs you use too.. lol... (assuming youre stock) i drive that drive quite regularly too, but then again, the motor has less than 20k, trans has about 12k.. haha, im practically driving a new car as far as the drivetrain goes..

 

30+ MPG is amazing, I would have to see it to believe it. I drive my car daily 44 miles one-way to work. Most all of it is highway and I average 75 MPH. I have my timing advanced 2*, run 89 Octane, have recently rebuilt TBI, new Knock sensor, Oxygen sensor, Rapid Fire Plugs, MSD Ignition, etc. and I still haven't seen any better than 26 MPG. I have been averaging 23.5 MPG and this is with normal driving accelleration.

 

I'd definitely believe it. Mine got around 30 when it was stock. Last time I drove on the highway for a while with the mods in my sig I got 28.5mpg. That was driving much slower than usual.

 

mine is pretty much a stock LO5... im almost driving a 1993 caprice with camaro clothes on.. lol. Im pretty sure the reason i got the mileage that i did was because i was going so fast, in overdrive, the faster you go, the more efficient it is ya know, so im thinkin that had a lot to do with it...

 

LOL!

That would make my car a Blazer in Firebird clothing. hehe

 

thats awsome dude.Its hard not to speed on that stretch of the I-5.What was happenin in L.A.You do anything cool

 

i hauled *** for quite a while.. lol.... 110 mph speedo's arent cool

 

Hey Cadillac I just did that drive about 3 months ago in my TBI car right after i did a header swap and new cat and spark plugs and wires. And i was doing about 75-80 mph and when i pulled over to get gas a Bakersfield I got 32 mpg!!! My car did really good all the way to L.A. if you dont belive me then divide 225miles by 7gallons. Our Little TBI can go far very well.

 

i recently ran I-5 as well. I was flirting with 150, but it was really loud lol.

 

I Need to get rid of my Speed Limiter

 

Oh yeah... E3 in LA last week. Electronic Entertainment Expo (3 E's, get it?). Check out the booth babes.

Anyway, I really enjoyed the drive. We live in a beautiful country. I got rid of my stock ECM mainly to get rid of the speed limiter and I'd say the next thing I would want to do is get a Corvette servo on the 700r4 so I can pull with the OD gear. At a certain point on the gas pedal, the tranny would drop down to third and keep climbing until I wasn't comfortable maintaining the revs. Letting back on the gas pedal would drop it back down to OD where it would only go just a tad faster -- around 120.

 

nice

 

I put the corvette servo in December and i love it. It really chirps my second gear. All i need to do is do my shift kit that i have already but scared to put in

 

We shoulda made a third gen meet out of that

very hot chicks

 

That's not entirely true. What happens at higher speeds is more wind drag. Drag = bad. The good think about speed is that it can bring your engine into it's most efficient RPM. The BSFC curve of a v8 starts high, dips low, and then slowely raises. If you can find that sweet spot of where it dips low then you're golden.
I have a hard time believing you got 30mpg at the speeds you were going, with an automatic AND a vert. Start in the mountains and driving downhill and maybe . To get that fuel economy it really helps to have an efficient drivetrain like a manual trans and fresh bearings/oil. Lowering the car, high tire pressure, and some other minor things can really help making it believable.
I'd like to set a goal for 30mpg highway and 12's to be on par with the LS1's. I think that would be awesome for a 3rd gen.

 

fresh oil, brand new transmission, pretty much a new motor.. the car is lowered at least an inch, 255/50/16 tires in the rear and it was non stop.. 360 miles, no stop signs, no lights, no nothing... just straight road... and im sure this had a lot to do with it.. i was caravaning with another vehicle, a ford ranger that i was pretty much drafting.. lol

 

Drafting... I love it even though it's considered "dangerous."
Just the other day I was taking a highway trip in our minivan and drafted some huge charter bus. This Toy(ota) Sienna has an info center that gives you approximations on gas mileage. None drafting it was ~27mpg, drafting just to the point where I was lifting on the throttle was ~37mpg. It would jump up and down but with cruise control I did the average and I think that's pretty darn good. I got a record "average trip mileage" being behind that bus .
I wish there was access to BSFC information from GM. I'd like to know what it is for some of these TPI, TBI, and GMPP motors. I also think water injection and a vacuum pump would help, but I don't have proof... yet.

 

lol, yup. maybe you could e-mail them and see if they will let you pick their brains... doubtful, but worth a shot