New "old" member.

[Longshanks]

Hi all, I was a member here several years and a couple computers ago when I had a '96 grand Am GT (biggest POS I ever owned). Lost my login info so I re-registered. Just bought a 2003 Impala with a 3400 out of an '04 to take over commuter duties from my 2001 Impala with a 3800. They're both base models but the '01 is loaded to the gills and has had a few performance mods like 3.42 gears, Magnaflow headpipe with the U-bend delete, high flow cat, resonator and a custom ECM tune. It's a blast to drive but highway mileage suffers with the gears and the daily grind is really taking it's toll on the body. The '03 doesn't have nearly as many options and nowhere near the performance which I didn't expect . I'll be looking to make improvements for highway driving. I have a 65 mile daily commute that is about 40 miles of 2 lane highway with lots of hills and curves and 20 miles if Interstate. Around town the 3400 does just fine but it's passing power on the 2 lanes and acceleration merging onto the Interstate just aren't cutting it. I'm looking for some simple mods to boost the highway performance without sacrificing mileage.

[LeftVentricle]

Gearing goes a long way toward the "seat of the pants" feel of acceleration. My understanding is the 3400 Impalas have a 2.84 final drive. FAAAARRR too lazy. My suggestion for your first order of business, before modifying the engine for more power, would be to swap that out for at least a 3.05, or even a 3.29. As you know, that will make a BIG difference. With stock size tires (225-60-16), the engine would be spinning at about 1900 rpm with a 3.29, which should still return good mileage.

[Longshanks]

Yeah, gearing would definitely help but I don't plan on going that far on this one unless something drastic happens to the transmission and since it was already replaced by the PO I'm not anticipating that anytime soon (knock on wood). I am going to put a TransGo shift kit in it though, the 1-2 shift is normal for a stock 4T65E, normal being pretty pathetic. I'm going to contact the guy that did the ECM for the '01 to see what he can do for the 3400.