well I would rather have real dyno performance gains than butt dyno. I didn't expect any gains from the Z tube, so I am not complaining about that, I just thought it would sound better.

 

ChaZM,
As far as the Z-tube goes, I don't think you will hear or feel a difference at all without the K&N Drop in, or a JWT Popcharger, also, if you just do the K&N without the Z-Tube again you will notice no difference, (the K&N will allow air to be sucked in at a higher velocity and pressure and the Z-tube does not have any type of silencers to muffle this noise -caused by increased flow, which the G35 Tube does). Now, the lower plenum was re-designed in 05, vs 04/03, which in turn has the effect of the spacer on a 04/03 model. So I think by installing the 1/2" spacer on the 05 might be making the area in the plenum too large for any power gains. Although, I think if you would have went with the 1/4" spacer on your 05, you might have had a similar outcome to a 04/03 model with the 3/8" spacer.

 

I guess the 05 is a different animal. You may have to keep your ear's and eye's open as far as the 05's are concerned. The mods that will work for the 05's might still be in their infancy. Keep looking and listening. Good luck!

I assumed the 03-04 G's had similar issues with the 05's. Guess not! We'll soon see.

 

im in the same boat with you chazm.. ive decided to get some mods that will def do something... POWERTRAIN! JWT CLUTCH FLYWHEEL.. and im also doing pulleys.. hopefully when i get my test pipes and headers on... that spacer will come alive.. i have the ut carbon fiber intake wich is kinda like the ztube but i got the whole kit with the filter and i can def hear a difference.. it sounds awesome! my exhaust is the hks and i could def tell a difference when i added it.. i can def feel the car pull harder with my mods.. i havnt got around to installing the other stuff yet so i will let you know around sept when i get home from iraq.. im gonna do a before and after dyno.... im really hopeing this next list of mods opens my baby up and really gets it going!

sorry to hear your dissapointed.. having a 05 i feel ya bro.. its kinda ****ty for us.. but at least we got that extra 15 hp on the older models.... hehe

 

^yeah, but too bad we couldn't keep the torque too, that would be sweet.

 

From what I remember reading from another post, the plenum on the 05 was redsigned in 05 to change the runner length and is a primary area where they were able to squeeze out the extra 18 hp (280 -> 298). It also is where we lost the 10 ft/lbs of torque. The varaible exhaust timing cam might have also played a part as well too though. I too read that because of the plenum redesign in 05, the plenum spacers you see are not putting down strong gains. The spacers were designed for the 03/04 models, which had a different lower plenum, so it makes sense that it doesn't perform the same.

btw, I too have the Z-tube and K&N and haven't noticed much of a change in power/sound, but I also haven't gotten above 4K since I'm only at 800 miles. I guess I'll never know what the stock tube sounds like, but I figured it wasn't too expensive for the parts I bought, and the dynos have shown that its worth a few Hp to the wheels so it puts me at 300 at the crank....sorta. I think I would have gone with the JWT, but I wanted my engine bay to look stock (just to avoid dealer issues), and I was concerned about the A/C line rubbing. I know I could wrap the line or pull the tube to the side, but I figured even the small risk wasn't worth the extra 1 hp the JWT is worth compared to the K&N.

 

Well my question still remains what is the difference between the 280 AT and the 298 MT. Where does the AT lose the HP that the MT gains. In other words what engine parts are different on the AT then the MT, and thus which parts could I change. I heard the Spacer on the MT was the difference now your saying those don't work on the 05's or are you just talking 05 MT. Thanks

 

^this was one thing, i think the main difference in hp

 

Different, less aggressive fuel maps also are one of the culprits.

 

DOES anyone have any more info on the variable exaust timing cam?