I wouldn't count on it gaining your MPG......who's to say that you have pushed the car a little less in a certain amount of time, or driving more hwy miles or even hit less red lights than usual. This last fill up i averaged 19.7mpg when I usually get 18mpg. This week i am averaging 16.7 so far, whelp, it must be because I installed my Z tube.

 

Or it could have been the Tornado or Fuel Magnets!

 

Its an 04 5AT if it helps.

Thinking about the air filter now.. Dont know if it will help with performance, sound, or MPG but hopefully it helps with something.

I used to push the G before and after I got the z-tube and I notice absolutely no difference even the slightest.

 

I installed my Z tube/K&N combo, shortly after I got my G. I have now logged some 2000 miles. I hope it does something. LOL, if nothing else, I guess I could say that I have 300+hp, now?

 

I get about 17mpg, and have a pretty heavy foot...got around the same with the popcharger, and stock.

 

You can feel the 'alleged' 6.5rwhp difference between 238rwhp and 243rwhp from 5500 rpm's to redline? That HUGE 2.6% increase is equivalent to dropping from a full tank of gas to 2/3 of a tank of gas... You think you can feel that slight of a difference?



BTW, independent dynos have PROVEN that the JWT popcharger AND Z-TUBE don't gain 6.5rwhp so "don't believe the hype".

 

your right Todd, the Ztube/Popcharge gains a lil over 4rwhp over stock AT PEAK but 8torque AT PEAK through the curve its a average 7above

I think the popcharger is worth it in cold areas or winters only in hot places.

 

I've seen dynos where the pop charger actually reduces low end torque (although it gives gain in the higher RPMs) which would not be good for an AT since this is the key to it's performance. You can compensate with the 6MT by dropping/slipping the clutch. It sounds good though.

 

I tried to tell you to get the injen CAI.....I'm loving it....I don't know anyone who has it that doesn't

 

I'm definite that the Z-Tube and K&N combo increases your fuel economy, and I came to this conclusion after testing it in as unbiased of a fashion as possible(Trying to drive with generally similar mannerisms in regards to throttle application and shift points, before and after my install).

Prior to Z-Tube, I always got 22-23.7 MPG during all of my test intervals(23.7 was the highest I'd ever gotten).

Since putting the Z-Tube and K&N filter in, I've been getting 24.7-25.x in each of the last 6 or so 1 week test intervals. In one year of driving prior to the Z-Tube/K&N install, I did not ever have a single interval where I got above 23.7 MPG. Now I am on a streak of 6 straight intervals above my previous highest fuel economy mark.

The past 2 weeks, I have been driving my car noticeably harder, since the weather is soo nice and I love the sound of the engine when it tachs up with the Z-Tube in there. My economy is still at around 24.4-24.7, combined.

That's pretty compelling evidence that you can't just ignore.

 

my next mod then

 

This dyno shouldn't be used for comparison at all..........they are two different cars, I bet if I dyno'd my car and someone else dyno'd there 05 6mt, we would come out with different #'s.

 

Well, I'm glad my thread has struck a fairly good discussion. I do now have to admit that the G35 is *slightly* louder with the Z-Tube now that I actually met up with someone else who had a G35 and we did some testing. At idle, it has a slightly, but noticeably more loud purr, which is kinda nice, but other than that the tone still sounds the same. Either way, I dont think its enough to warrant the $75 price tag, and I would probably not reccomend it anymore to anyone who inquires about it. Its a slight difference that you can barely notice unless you are really in tune with your exhaust sound, until you compare it with the stock g-tube.

The air filter and the gas mileage sounds pretty tempting, since thats always something I would like to improve.. What I will ask you, while you did to extensive testing as it seems, how many miles did you have on your car prior to switching to the K&N air filter? Besides road conditions and other factors, if the mileage on the car was somewhat on the high side, the stock air filter could have been dirty which would be what was somewhat robbing the gas mileage, and why when you put the new one in, it was better, so Im just wondering about that.

 

I put the K&N filter on at about 9300 miles. I drove with the K&N filter on my car for about 1000 miles and saw no noticeable gain in fuel economy. After that 1000 miles, I put on a Z-Tube, and my fuel economy soared. I've had my Z-Tube and K&N filter on now for about 1500 or so miles, and reset my fuel economy gauge in the Navigation system 6 times since adding the Z-Tube.... each interval, of which yielded fuel economy readouts well above my previous(pre-Ztube/K&N) record highs.

I can't think of any other variables that could possibly cause my car to suddenly have such a change in fuel economy.. especially since I've been driving it harder than usual for the last 2 weeks of my testing. I even drive my car mainly on the same routes, during the same times of day.

 

I've been driving harder to try and see if I can hear a difference, everyday thinking it might sound a little better. It hasn't and I currently am getting 16.0mpg since sunday....b4 the Z tube I was averaging about 17-18, last week I got 19.7.