A quick synopsis:

Step 1 - Stillen Intake = loss of low end torque and an inability of the car to rev up fast under load.

Step 2 - Stillen intake removed and replaced with a Home Depot CAI (as seen on my Homepage) = regained torque, rmp's and got a little more top end.

Step 3 - Stillen Y-Pipe installed = more top end (over 100mph) and a loss of torque. However, the car was able to rev up to redline.

Step 4 - Reinstalled Stillen Intake = Shift patter smoothed out (auto), car seemed faster than with only the Y-Pipe and the engine seemed better balanced. The noise is starting to take [/COLOR] away from the luxury aspects of the car. It's not bad, but it is noticable.

Step 5 - Installed HKS Rear Section = The car felt more free flowing. The extra power is minute compared to the increase in noise. There is a drone at 2k to about 2500rpm, bad combo with an auto. This is a hard setup to live with. Car felt strong at speeds of above 85mph otherwise it bogged around town or at least sounded that way.

STEP 6 - Uninstalled the Y-Pipe and all I can say is WOW! This is the best mod yet. According to my G-Tech I shaved over 1/10th off my 0 to 60 time. In addition, my car feels so much faster, the drone is gone, the loud sound is gone, and now my car sounds almost like a G35. It has a slightly deeper pitch than the G's and Z's but it does have that throaty gurglie sound.

So this is it, no more f'in with the engine. Stillen intake and an HKS Rear section is what's on now. The only other thing that I am going to do is to get a B-pipe in 2.25 and not 2.5, stay with the 22" resonator and call it a day.

 

That's funny because you definitely lost hp w/ uninstalled y-pipe

 

It'd nice to see some dyno number to prove your theories. Each car is different. But if the car feels better afterwards more power to you.

 

considering it's a stillen y-pipe, anything is possible. For some scary stillen y-pipe stories ask HNDA ETR

 

Step 3 makes no sence, top end power is incorporated with high rpm, anywhere from 5k and above. Not you’re gearing and (over) 100mph speed.

And BTW, I had the gtech pro meter, and it's a over priced POS. And how do you lose torque with a y-pipe? If you think a y-pipe makes you slow, just imagine how slow your car will be with a SC.

 

The "loss" of torque you mentioned will occur in the low RPM range when you reduce backpressure in the exhaust system. That torque is regained (and maximized) in the mid and upper RPM range. Of course with an auto, the ability to wring out the performance of a y-pipe is somewhat less pronounced than if you had a manual. Keeping the engine in the mid/upper RPM's is the best way to utilize the power/torque with the y-pipe/exhaust setup you "had"
Also, the HKS exhaust will be loud with a y-pipe. Many threads mention Cattman and Frankencar is the "most" quiet exhaust systems for our cars. So I am not surprised that the noise was a little too loud for ya.
As for the intake, the best choice for ANY car will always be a CAI for maximum HP.
Look at ANY race car, and you will note they ALL have a CAI system of some sort. Cold air=HP.
So, in the end, only you will be able to decide what feels the best for you. Your driving style and the type of transmission will effect the outcome of your mods to some extent. No one can tell you what feels/works/sounds best, for that determination can only be made by you. Have fun.

 

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heyy...how r u..im fine chilling and READY to go shopping! yay

 

Are you drunk?

 

I took off my shocks and saw major HP gains

 

Brilliant post, just fu<king brilliant

 

fu is greater than king

 

Turbo GG, you said it best! Since I don't like to rev out the car at every light and drive it at its upper end all day, why have the car setup for that. I realize that my car is an auto. If I had a 5 speed I probably would have left it on the car because only time that the y-pipe felt faster was when it was going downhill or revving out.

Carabuser, I believe that my Stillen Y-pipe is of good quality with no rattling and a perfect fit. It also has the best looking collector of the bunch. Ceramic coated and still looking beautiful.

 

i have the stillen y-pipe, and it's not bad, maybe i got lucky haha. But anyway it sounds to me the real problem is the transmission. It's a clear case of slushbox-agony. To remedy this, just get a manual.

 

When i put on my y-pipe, which is from stillen, I got incredible gains (over stock), especially since i fixed my VIAS and mated it to my custom cold air intake, my car feels really powerful compared to before. Maybe u rstillen y-pipe had an exhaust leak in the flex section?

 

TQ is loss through reduce velocity of exhaust gases (cooler) from bigger than recommended piping. A Y-pipe normally shouldn't lose any low-end power whatsoever, so I guess his is a rare case where he felt a powerloss.

 

There is no exhaust leak in the flex section. The install was perfect and Stillen's Y-Pipe fits like a glove.

As far as power loss, maybe there was none. There was however, a torque loss at the lower rpm range and therefore made the car feel slower.

Yes, I agree that velocity has everything to do with torque. Hotter air moves faster. A larger diameter pipe will only allow the gases to cool faster slowing their movement down and reducing torque.

I'll take the torque any day over the couple of extra horsepower as torque is what you feel.

By the way, manuals and autos behave differently, With your manuals, you have to ability to drive the car where the powerband is. Not so with the auto, unless you manually shift it.

 

It's alot easier to change the y-pipe over the transmission. However, I was thinking of it before I took off the Y-pipe. I still wish I had a manual and if I ever do switch, I will try the y-pipe again. For now I think that I will work from the rear of the car to the front and get myself a B-pipe w/22" resonator to see performance and sound changes.

 

i did not mean change the tranny haha. with the 6 million of them around, it's more economical to just buy one instead. And of course the auto is going to suffer from mods because it naturally stays in the low rpms, primarily to conserve fuel. and since most modifications promote upper rpm hp, often sacrificing low end torque, you're probably best off with stock eqiup. If you were looking for all out torque, the best setup involving the parts you have is probably the intake, and cat-back. The y-pipe gives some impressive gains though, so it's all a tradeoff. or you could go completely stock except for the y-pipe. That will give you a decent sound, pick up a few lb-ft, and a couple hp, while not sacrificing your backpressure. And switching your b-pipe alone will probably doo little for your sound issues. The closer you get to the engine with the piece you're replacing, the most change will be noticed, hence headers and a y give the best gain.

 

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I have the Stillen Intake, Cattman Y-Pipe, Cattman Catback & a Stage 2 VB mod on my auto with no loss of low end torque according to my butt dyno .Actually just the opposite. I used to have that dreaded 3rd gear fallout at WOT because of the 3rd gears long ratio... but no more. Pulls very hard to redline & shifts on a dime. Couldent be happier with my Y-Pipe. I guess to each is own.

 

yeah i have a pop-charger intake(homemade), stillen y, CM straight pipe, and Greddy cat-back, and i definitely gained both torque and hp across the board, but of course most obviously above 5k. I too am satisfied with my engine's current breathing state. that is until the spring when cams are to come.

 

Thats the same thing I found when I installed my y-pipe.

 

Off topic but JayMax2000 I wanted to do something similar to my grill but dident think it was possible on my 2000. What exactly did you do to your grill?

 

well not to argue with everyone, i just found this on technosquares site...it looks like the ecu actually compensates for modifications that it can sense from o2 sensors...which would make sense in this case
http://www.technosquareinc.com/maxima.htm
(about 3/4 of the way down the page under "Changed air intake system")

just realized you had a different year, it still may hold true though

 

What the heck is all this?

 

The ever present f***wad theory
http://www.penny-arcade.com/view.php3?date=2004-03-19

 

Anyways... about the y-pipe... it does sound a lil strange to me... I'll comment when I put mine in.... although I do have a 6-speed....

 

Time to ban those ******

 

Any short ram intake will reduce low end torque, due to the fact the piping is greater in diameter. Intake velocity gets reduced at low engine speeds, therefore less low end power, but once the engine gets above ~3000rpm, the larger diameter allows more air to enter than the stock setup did, so you see gains. As for CAI vs Hybrid, this topic has been beat to death, and someone actually did dyno runs on both, and the Hybrid setup saw more gains than the CAI, at least above 3000rpm. The CAI would be more practical for everyday driving seeing as how it helps the car scoot a little faster from a stop. Advantage of a CAI over a short ram can only be measured when the car is moving below 20mph. This has already been tested, once our cars are moving above 20mph, engine bay temperature and the temperature in the fender was less than a 10 degree difference. With temps that close, once the car is moving above 20mph the advantage of the CAI is all but non-existent, however the extra restriction due to longer piping is still there. So above 20mph or above 3000rpm, the CAI doesn't perform as well as the shortram/hybrid.

The stock YPipe is not very performance oriented, lot of restrictions, considering it also has 2 built in cats. Replacement with an aftermarket piece reduces "back pressure" but thats not why theres more power. Back pressure has nothing to do with making power, its all about exhaust stream velocity. With the restrictions, exhaust velocity is greater at low rpm(below 3000) but above that the poorly designed piping and cats inhibit it. With an aftermarket ypipe, due to less restrictions, doesn't perform as well below 3000rpm, but the gains above 3000rpm are more than worth the loss below, from a racing viewpoint. Back pressure is a term used in old muscle cars, where it was needed for those engines to run properly, with engines of today, back pressure still exists, but eliminating that doesn't necessarily increase power. If you ran an open manifold, you would have no back pressure, but you would probably not see any gains in the rev range of the maxima when compared to a 2.5in ypipe.

TK

 

Uh... okay... thanks...

Seriously... what waste of our bandwidth and time....

 

is everything all better now

 

I have a stillen y pipe with a greddy evo catback and place racing cai, so far the car runs fine..The y pipe was free anyway heh