Improving Engine Efficiency & Performance

[IanSzgatti]

If you make the car lighter, you loose inertia at highway speeds

[CobraCDR]

chng final drive ratio

[onefastV6]

The difference in weight between the transmissions is only around 25lbs.

Too bad we don't have good source for aftermarket rockers....it would be interesting to use different ratio rockers on the intake and exhaust.

[torq455]

a 65E is heavier. you'll be putting money from your gas savings into the tranny swap. go with less intake lift and a lot of exhaust lift and duration and raise compression. if possible have TCC lock sooner.

[onefastV6]

I am probably going to start out this weekend and change the plugs, and start tweeking the current tables. I am also thinking about getting a 2.5" down pipe from ZZP, as the grand am runs a very restricted down pipe. A 4t65e HD will eventually replace the 4t45e when I have time to get it in.

It would be nice to get a set of budget shorty headers made or something similar to ZZP's "power log". https://www.zzperformance.com/products_img/208_1.jpg

A few other things that I am going to look into are the lower intake manifold from the equinox and torrent, and different injector spray patterns.

[merlot566jka]

variable valve timing, variable intake runners, direct injection....bla bla bla. by the time you spend all that money you could have bought a car that gets better mileage.

i stopped buying beer, no my gas doesnt seem like that much of a burden.


you can lighten the car, reduce drag etc


basically an engine is a pump. make it pump easier and you can increase efficiency. but then you have to accept that an engine doesnt stay at one speed, so i cant be 100% efficient at all times, only a certain rpm range.

then you have to accept that the engine is only about 18% efficient as far as power it makes from the fuel.

there are many things automakers are doing to make an engine more efficient. ive listed a few above.

if you raise the compression ratio, you can burn the fuel in the chamber more complete than with a lower compression ratio. but to do that you need better fuel atomization and control...hence Direct Injection.

you can reduce friction, but you cant really get much better than whats stock, unless you go to needle cam bearings, and other extreme things used in race engine.

you can aim your cam's peak torque to your cruise rpm, that will put your engine in its most efficient range while you cruise. where your engine makes your peaks torque is where its closest to 100% VE

you could also take advantage of helmholtz resonator, and tuned exhaust lengths and things along those lines

[Superdave]

I don't think you'll get it that high without running it dangerously lean...

[onefastV6]

With the gas prices on the rise and not wanting to spend money on another vehicle, I am brainstorming ways to make the 3400 and 60*V6 engines in general more efficient. From personal experience I was able to get 33 MPG on the highway in my 01 grand am when I had 3500 heads, 3500 LIM, 65mm TB, TOG headers, tuning and a few other minor mods.

Since switching the car back to stock mileage has suffered, which now has me thinking what can be done to maximize fuel efficiency. I know the obvious is to ensure that the car has had it basic maintenance and that tire pressure is optimized, however that only goes so far.

Thoughts and opinions on the following:
1. Heads, intake manifold design, and compression ratio relating to Volumetric Efficiency
2. Exhaust, improving flow (the stock log manifolds are horrible)
3. Valve train (cam design, lighter valve components,
4. Fuel system (optimal fuel pressure, fuel injector spray pattern, ect)
5. Spark (Plug Gap, optimal spark tables for a cleaner burn)
6. Gearing
7. Lubrication & bearings
8. Tuning

Anyone think it is possible to get 38-40 MPG out of one of these engines without making it a total dog?