If the most powerful mods are:

1. high flow cats/test pipes
2. y-pipe
3. intake plenum

Which of these yeilds the most power?
Or is there another (more powerful) mod for under a grand that
I am missing?

 

If your looking for power...then the plenum is prob. your best bet.

But for under a grand you can also improve your handling greatly...so thats another route...and depending on your driving type the latter will be better for you.

<font color=blue>2004 TB 5AT Sedan</font color=blue>

 

And the results will be even better if you combine the plenum with cats, for example. This can be had for $1,000 (including install of the cats by a shop).

'04 6MT coupe

 

I would say crawford headers they go for right about a $1000

 

Fact: the Z-Tube adds about 5rwhp across the power band
Fact: the Z-Tube can be had for under $100

Fact: the Y-Pipe adds about 5rwhp across the power band
Fact: the Y-Pipe can run from $200 to well over $500

*Conclusion based on the above facts... Get the Z-Tube FIRST!

Opinion: The High Flow Cats, Plenum and Z-Tube combo are the best bang for your $1000.

Fact: the combo in the opinion above will net you ~20bhp on a 2004.5 G35C-6MT.

Fact: for the coupe, there isn't one exhaust that you can buy for $1000 or less that will get you close to the gains that the above combo will.

 

You forgot NITROUS OXIDE !!!
Most HP for under $1000.

'04 G35X Graphite/graphite, NAV, wood, premium

 

I have done the following for under $1,000 with very good result, six-wire grounding kit, Kinetix intake plenum, z-tube with modified air-box opening. I have the test tubes sitting in the trunk waiting to be installed. For now, these will be run through the stock exhaust. Two weeks ago, I ran my car (completely stock) at the drag strip for a baseline. As soon as I get time I will run it again to see how these mods worked. For now I have been using my niece as my butt dyno and she's been impressed with the results, lets hope the drag strip is too!

 

"FACT: Only you can prevent a forest fire!"

 

Whats the point of making power if ur not getting ne speed from it. Im gonna go for the 3.9 final drive ratio and the grounding gear wiring kit for about 1000 and probably end up with a 1/4 mile time decrease of .3-.5 seconds. I already have a y-pipe sitting under my bed so i dont know what kind of performance will be gained from that.

 

buy a 500 dollar beater, drive it for a week. Then come back and drive the G. Its a mental mod.

04 G35C 6mt/aero kit/nav/premium

 

I do have the Z-tube on order, so I'm already looking for the next best mod. The Plenum does seem to be the most popular around here.
________________________________________________

ON Order:
2005 Red on Wheat Automatic (NON-Sport model & Proud of it!)
Performance Tire & Wheel Package (18” Tires with 18” 7 spoke rims)
Sunroof
Splashguards
XM Radio
Trunk Mat

Aftermarket on order:
K&N Filter
Z-Tube
Lex Sheild Headlamp Guards
Soundstorm Lab 1300watt 5 channel Amp
4 JL (VR650-CSi) Speakers

 

Remember the "air flow balance theory". You can modify the Z-tube and plenum if you like, but you're only modding one side of the air flow system. You have an intake and an outlet side (exhaust side). I personally have been alternating my modding. I did one intake mod, one exhaust mod, another intake mod, and another exhaust mod.

Basically there are several choke points on our cars. Everyone pretty much agrees that the stock intake tube, plenum, cats and y-pipe are the 4 choke points (especially on the coupes). If you modify the 2 intake parts, but leave the 2 exhaust parts stock, your car will not be able to move air THROUGH the entire system as efficiently as if you alternate your modding.

Just something to consider...

 

Good point Neffster. But I think that the plenum would do ok as a stand alone mod though because it is sending more air to the 2 "choked" cylinders and not necessarily increasing the overall airflow for the entire system.

The plenum will probably be my next mod when the APS comes out. I've been debating the cats for a long time now, but I just can't seem to get myself to pull the trigger on it.

 

All of the mods mentioned below will help power in the upper rpm range. This is great for the track where you'll be up there but not as beneficial for the street.

Based on that, I'd go with a lighter weight flywheel and change the crank pulley. Both of these mods will affect performance throughout the entire rpm range instead of a portion of it.

All other things being equal, I'd take a car with a lighter flywheel and pulley over one that has the z-tube, plenum, and cats.

Peak dyno numbers are one thing but it's the total area under the curve that matters. If the mods only help at certain rpms, their benefit has to be a multiple of another mod that adds power throughout the entire rpm range. I hope I've made sense.

 

Get the Stillen exhaust system, which includes the ypipe/x-pipe. With the left over money, get the Z-tube and K&N drop in. You will gain 20~hp.

.02 cents

2004 Infiniti G35S, 6MT, Premium, Sport, DP
Mods: JDM Clears, 20% tint, Z-tube, Stilen CAI
Track: 14.32 at 98.79 mph 2.2032 60ft
Dyno 07-07-04 - 234.2 hp & 233.8 tq
http://www.g35world.com