2003 vs. 2004 Z06 Difference?
 

Are their even any?

2004's didn't get an owners video. GM removed an accessory plug under the console. 2004's got better tuned shocks. I can't think of anything else off hand besides the Z16 option.

The shocks were the biggest change. I installed them on my 03, there is a difference.

It's hard to prove but owner reports seem to indicate the 04's are a little stronger. It appears some of the fat that GM built into the LSX series of motors was taken out yielding slightly more HP. Many 04 owner's report getting "lean" codes when they install any low restriction intake like Blackwing etc. Where as, on almost every other LSX motor even after installing an intake the AFR's are still rich. If I had to guess this factory tweaking (if true) may have yielded another 5 HP or so. But every little bit helps. Again there is no official confirmation by GM on this, just anecdotal evidence based on what 04 owners report on the forum.

Hopefully some 04 owners will respond with their opinions as well as dyno numbers and if any of them experienced the "lean codes" after installing an intake.

Tom

I believe the 04 got an updated fuel injection system that it shares with the C6, though it wasn't supposed to provide any more power.

Can you give a little more detail around this plug? Where exactly was it located and what was its function?

[QUOTE=Craig99SVT]Can you give a little more detail around this plug? Where exactly was it located and what was its function?[/QUOTE

Do you mean the accessory plug located inside the center console? Or the plug in the plug in the footwell near the fuse box?

I have also heard for a lil tiny extra bit of performance the 04 Zs run slightly leaner from the factory vs 02 and 03 Zs (for a slight if not negligible extra edge in performance)!! :cheers:

From GM Hi Tech Magazine...

"Changes for the '04 Corvette Z06 include Nuerburgring-tested, re-valved shocks and a new carbon-fiber hood."

Dave

Actually I believe it was updated in the mid to late 2003 model year.

Yes I think it was that one.

Howdy!

That's the FFS fuel system - it actually started in the mid '03 model year - mine Z is an '03, built in April '03 and it had it.

The downside is the slight revision to the pump and lines (I believe the regulator is _in_ the tank integrated with the pump and no return) means that there's a lower upper limit to fuel delivery with big mods (particularly FI setups).

Though it's not a huge deal to drop the tank and completely redo it (some people use a 97 fuel system, with return, rail mounted FPR, big pump, etc.) Not a hgue expensive relative to everything when you get to those 600+rwhp level though :)

04s have top-post battery terminals too.

The '04s also had softer rear sway bar bushings and stiffer front control arm bushings (don't remember if it was the upper or lower control arms).

Accessory plug
 

I have the plug in the console on my '04. :thumbs:

-Mr.Z-06

by plug in the console, do you mean the "cigarette" plug, for c-phones and the like? That was in my 97...

That is not what I was talking about. All C5's have a plug in the console.

04s also have different rear O2 harnesses and a different T-Stat (same as C6).

The item (that I'm aware of) that was removed for '04, is a switched power accessory block, that's under the passenger side kick panel.

That's where I hardwired my V1 - I remember posts of '04 owners trying to follow the forum hardwire guides, they were confused that the accessory block wasn't there!

DT

You are correct, the auxillary power harness doesn't exist in the 04s. You can get power at the fuseblock for a fuzzbuster. :thumbs:

It sounds like you may be missing the entire picture with this situation. The lean codes are tripped during closed loop cruising operation. The rich AFR's reported by most after an airbox install are happening during WOT open loop operation. Even if an 02-03 is not setting a lean DTC chances are excellent that the initial fuel metering is lean and the PCM is attempting to correct with positive LTFT.

A 2004 car that sets a closed loop lean code will also run rich when going WOT open loop. The car runs rich when at WOT to save the cats and the motor.

It sounds like you may be missing the entire picture with this situation. The lean codes are tripped during closed loop cruising operation. The rich AFR's reported by most after an airbox install are happening during WOT open loop operation. Even if an 02-03 is not setting a lean DTC chances are excellent that the initial fuel metering is lean and the PCM is attempting to correct with positive LTFT.

A 2004 car that sets a closed loop lean code will also run rich when going WOT open loop. The car runs rich when at WOT to save the cats and the motor.