I'm definitely not running as fast as I should. I've had a few different people tell me that it should be faster with the mods I have.
I'm wondering if my exhaust is too open and I don't have enough back pressure?
After the stock headers, I have a Warpspeed Y-Pipe, Magnaflow High-Flow Cat, then 2.5" piping back to an OBX Racing muffler.
I'm thinking that it's just too wide open.
Ideas:
1. Resonator - If I put a resonator back in the mix. Will that help with the back pressure or just the sound?
2. Muffler - Possibly going to a dual tip muffler. What about leaving the 2.5" Piping and going back to a stock muffler?

 

I've read numerous threads here on the org about the Warpspeed Y pipe, and that it gives little or no HP gain over the stock Y pipe for our 00/01's. The design does not allow for efficient exhaust flow. I suspect that is your problem. Change the Y pipe first. Adding a resonator will only reduce the noise level, and little else. Adding a dual tip muffler, or returning to a stock muffler won't add HP, whether or not you keep the Warspeed Y pipe on. I've read that the best choice is the Cattman Y pipe for our model years, it gives us the most HP gains.

 

I don't think it's a Y-Pipe issue. I don't think the big difference between the Cattman Y and the Warspeed Y is as much performance as it is sound.

 

With 2.5 Inch tubinig you are ok, if you had 3" you may experience some vacuum and turbulence. the 3" if you are boosted. foru our displacement and HP that is ok. I have pretty much the same set up, I used a Magnaflow perforated core resonator, do not use a louvered one. The louvers sticking up will cause more turbulence, and more back pressure. Same for your muffler. Louvers in the air stream are bad. I have the stock muffler for now, but have a magnaflow perf core waiting to be installed. Also intake. If you have stock, you are limiting the amount of air in. Exhaust out can flow ok, but you need to open the "Mouth" I have a JWT pop charger. Besides it removed the precat, have you looked at the tubing for that? It winds around then out. The warpspeed Y eliminates that, and is 2.5".

I have not yet dyno'ed though, but I know I have more HP. with all that and UR UDP.

 

I have a Weapon R Intake so that's not an issue.
VQ, what muffler do you have?

 

http://forums.maxima.org/showpost.ph...1&postcount=33

in the 4th gen modification FAQs, IDK if it is in the 5th gen.

 

I was thinking of purchasing a High Flow Cat. Does that increase Sound/HP???

 

By 1-3 hp of that.

 

First what are you basing yor conclusions that your car is slower than it should be...dyno/track? With the stock heads you are fine with your setup. Even if you had headers your car would still be fine. Your car is not slower due to loss of backpressure, if you are positive your car is slower, you may have other issues.

 

It may be that I have other issues.
I'm basing it on the opinions of other current/former Maxima owners that have driven my car. Also, I ran against a 4th Gen the other day that had Intake/Y-Pipe/Exhaust and I didn't start pulling till about 50mph.

 

cheapest thing for concrete evidence would be to take it to a dyno as juice mentioned. gets 3 pulls with a/f and see the true numbers. you can take out alot of the guess work and even be able to pinpoint where it could be losing power alot quicker than just replacing parts.

 

Yeah, a dyno would be best.

 

How detrimental to horsepower would it be to put my stock muffler back on?
Sound is becoming more of an issue these days. I'd also like to go back to a dual tip muffler. How much would I lose going from 2.5" piping to the stock muffler?

 

Look at my dyno numbers and track times...those are with a stock muffler...I do not believe our stock mufflers are restricting at all.

 

I have a 2000 maxima with warpspeed y-pipe installed...does anyone have dyno proof that you don't gain much with the 00/01 maxima's with any y-pipe?

 

ive noticed that those hi-flow cats arent good for our cars unless were aspirated , we need back pressure to pull hard.

 

Your VIAS is probably broken or your MAF is no good. Alot of people blame this n that for their slow performance. My car has severe traction issues, and I ran a 4th gen in my car with about 300lbs in the trunk and my GF in the pass seat-100lbs. Since I was traction limited he kept up with me till I regain traction and I catapulted so hard on him it wasn't even funny- guy kept on insisting I had a SC under the hood at the next light. How many times I gotta tell those people that its not SCed, last G35 coupe I ran told me I spray NOS... DE-K power ! even with a broken VIAS.

 

That sounds about right for a moded 4th gen vs. moded 5.0 gen

 

You think that sounds right....
4th Gen
Intake - Y-Pipe - Exhaust - Auto

Me
Intake - Y-Pipe - High Flow Cat - Exhaust - Lightweight Flywheel - Manual

I'd only start pulling at 50?

 

do you have heavier wheels than 4th gen? did you have any extra weight in the car (subwoofer, laundry, whatever). I doubt your VIAS is broken since you did start pulling after 50 mph. Also a simple thing as tune up might help. How long ago did you change/install your air filter, cleaned your injectors etc.

 

Reset the Ecu, I dunoo what Else to Tell you unless you Dyno!!1

 

I am sure you've been told before, and below, but back pressure is an oxymoron and is bad. It's like pluggin up your exhaust. That's what back pressure is. Blockage of FLOW.

 

You never said the 4th gen was an auto

 

Sorry about that...

 

I think weight was basically the same.
I'm going to use Seafoam today and we'll see if that helps.

 

Do you have the 17" wheels? Those are a lot heavier and could make you slower.
Have you kept up with maintenance? Tires and launch could have a big effect.
Check for codes.

ONCE AGAIN CAR ENGINES NEVER NEED BACKPRESSURE!!!!!

Stock muffler and cat is fine for most cars unless you want the extra noise and smell (for test pipe). If you are big n20 or boosted then maybe not.

EVER

 

Rich whats good man? When we linking up again!! I'm thinking of replacing the MAF. If ur interested, maybe we could get a bigger deal. My mods are finished except to deaden interiror noise.

 

The 4th gen does weigh less. BlackBIRDVQ if your max took out a G35 coupe, im guessing it was an automatic and you had a manual, that might be true.

A G35 on a manual tranny would rip you apart even if you did use NOS

 

I would check his mods and 1/4 mile times before you make that assumption. His car is probably one of the fastest if not THE fastest N/A 00/01 Maxima on the board.

 

Then yourself Gennady7.

He doesn't run in the 1/4 does he? I don't think he cares what he runs in the 1/4, from what I've seen him post....

I agree from his modlist, but I wonder if we will ever find out from a timeslip...

 

Has anyone stopped to consider whether or not Rich's problem is bad gas?

There have been a couple of times when my 02 Maxima felt noticeably underpowered for no known reason but, seemed to be "cured" when I re-fueled it using different gasoline or got gas from a different station.

 

Manual G35 isnt much.. its a low 14 second car with a good driver. They are not the eassiest cars to launch right on the street. One time I was at the track with bad VIAS- still on the car (sometime it opens and somtime it dont), 90 deg heat, trunk full of stuff- 200lbs, and nasty boggn off the line, with like 2.7 2.8 60' times I ran 15.1@95MPH. I know from a fact if I can hang pretty good 2 cars from 70 to 130MPH with my friends 12.6 in the 1/4 mile EVO, then my car has enough ***** for me. I aint claming no awesome times here, as I do not have the slips to prove it. I do have dyno sheets that show more than alot of 3.5Ls put out with all bolt ons.

 

I got a stillen y-pipe, high flow cat and greddy exhaust. would adding a bigger resinator affect the flow of the exhaust at all ?. All I want to do is quiet it down some. Without losing any power.

 

if its a good brand resonator- like a Magnaflow your should be alright. I started to hate my Greddy just for the noise it makes lately. I been trying to do a straigh up trade with my friend just for a Cattman rear section, and I was going to get their B-pipe, to go along with Cattman headers. I was never a big Greddy fan- any of their products.