So, I have had my car for a couple of weeks, and I also have a '98 GT. I have noticed at low RPM's, particularly 2nd gear, the '05 doesn't seem to have a whole lot more than the '98. Obviously, at 3000+ RPM the '05 comes on like crazy. Coming out of the hole, the '05 get to redline a lot more quickly, but I am still a little shocked at the comparison in low 2nd. It seems like, while the car is quicker than most at 1500 or 2000 in 2nd, it doesn't throw you back in the seat. It is almost as if I have to floor it through 1st and 2nd in order to get the "full effect" of the 5.1 0-60 time. If this is an obvious observation, I apologize. I was expecting it to be a very noticeable difference at all RPM ranges, but as I said, it really doesn't show much of a difference from my '98 until around 3000. Anyway, feel free to comment on this observation. And don't get me wrong, this car flies, and I love it, I just wonder if the ratios are different (not the final drive, the gear ratios) from the '98 to give it more pull at top end and also to compensate for the much lower 355 in the '05 as opposed to the 308 in the '98.

 

Throw on a CAI and a tune and you will notice the difference.

 

A generality: the more valves per cylinder, the lower the low rpm power and the higher the high rpm power, all other things being equal. This is generally caused by lower port velocity at low engine speeds for multi valve engines (but better cylinder filling at high engine speeds) vs 2 valve engines.

Or, in other words, what you have noticed is exactly what should be expected. And I would expect a 4 valve engine (4.6L, normally asparated of course!) to have even lower low speed power and even high high speed power. from what I have read, they mostly do.

 

Any additional opinions?

 

Mine pulls hard as heck through all gears with no throttle lag what so ever and makes my last car which was a 98GT with upgrades and 260 HP seem like it had 4 cylinders!

 

I feel that for the normally aspirated 281s, the 3 valve represents the best combination so far when it comes to overall performance. Yes it's a little weaker down low than the 2 valve motors, and breaths a little less up high than the 4 valve motors, but over the entire spectrum performance wise, the 3 valve bridges the gap between low end grunt and high end zip quite well.

 

yea and how much does a CAI tune cost??

 

I just wanted to make sure my observation was not so far off that there may be something wrong with the car. I am almost certain that is not the case. I was just hoping no one would come on here and say "Wow. Not my car. It pulls like a Porsche 911 twin-turbo at all RPM ranges" I am guessing that is not the case for anyone.

 

Most cold air intakes come with a couple of tunes, and the tuner will most probably have the option to accomodate the CAI. Depending which model you buy, you might have free canned tunes from the manufacturer, no cost.
So far, I found the JLT CAI for $200 shipping included, and one of our TMS members sold me a Predator tuner for $200 less than original price, so defenitely not too bad! I'm hoping I can have the CAI, tuner, and SLP Loudmouths done as soon as I get home when I pick up the car!

 

WOW. That's nothing like my car, it pulls like a Porsche 911 twin-turbo at all RPM ranges