I need to know what size B-pipe do you guys have on your Maximas. How many of you have 2.5 and how many have 2 1/4 inch piping. The reason I ask is because I have 2.5 inch piping in the back along with a cutout and I think i'm losing too much backpressure and losing HP as well. I'm going to the dyno on sat. to see how much power i make with the cutout closed and open.
I'm seriously considering replacing the 2.5 with 2 1/4 inch piping but I need to find out what you guys have.

 

2-1/4"

.......

 

Replace it.
I've got 2.5" straight pipe now but I'm gonna be adding an AEROturbine muffler to it shortly.
hopefully that will help somewhat.
If not I'm gonna put a 1" tip on the car and strangle it to get back my backpressure!

 

so what's better, 2.25 or 2.5?

 

well the 2 2.5" guys appear to be whining about their missing "backpressure" *cough* exhaust gas velocity *cough*

Then again Jeffy seems happy with his 2.5" catback soooooo.....

 

jeff knows nothing any way im still waiting to here back form him about a valve cover for the font of the ve

 

I believe mine is actually 2.25" or something also. But I built my Y with a 2.5" in/outlet flex section and the 4-gen hi flow catco cat was also 2.5". But I have ball joint flanges so.........

 

i'd like to know what the vg30e guys are running for their exhaust. specifically i want to know the diameter of the cat and b-pipe.
mine is 2.5" and like some other people here, i feel as if i've lost a lot of low end power.
so any input is appreciated because i'm going to have my exhaust redone in a few weeks. i don't want to goof it again.

thanx

 

10" All The Way

 

^^^ Sewer Pipe maybe?

 

bwahahahaha you guys are soooo funny

 

Here's a dumb question-
Does back pressure increase or drecrease mpg?

 

Yes you are right.

 

it does nothing
research exhaust gas scavenging

I for one am surprised 2 of the SBC ****** ITT are using the term back pressure

edit: Jeffy beat me

 

"SBC ****** ITT " WTF is that supposed to mean?

Backpressure can help and harm gas mileage
There is such a thing as too much and too little
Too little back pressure in my case

 

SBC = Small Block Chebby
ITT = In This Thread

Maybe I suck, but how can exhaust gases pushing their way back into the cylinder can help make power.

 

I am currently running 2.25" and I think it is just right. The only time I would increase the size more than that is if it was turbo'ed.

And I have not done a swap so this is a VG opinion.

 

well, looks like its back to the muffler shop for me; guess im gonna have the 2 1/4 put on. I'm just sick of having no low end power and sometimes it seems as though my car is fast with the cutout open or closed.

 

Seems to me it's always been widely accepted that the standard upgraded exhaust size is 2.5". I have a 2.5" WSP Y-pipe, 2.5" high-flow cat, and a GReddy catback and I have darn good low-end.

BTW - the GReddy catback diameter is something weird like 2.47" - given all the D&D behind developing a catback I'm sure the diameter of the GReddy tells us something when it comes to the best 'upgraded' exhaust dia. size

Also... 5 ltr. beater - are you auto or 5spd? If you're auto I'd venture to say that most of your 'low end loss' is just due to your being an auto.

 

I measured the Greddy at 2.25" Inner Diameter at the middle flange. Could have been more though, I think I used a crappy wooden or plastic ruler I had in the garage. I was more interested in getting it installed though lol.

 

This argument is pointless because the klowncar exhaust is greater than all.

Cliff notes = klowncar exhaust > *

 

can anyone confirm this other than yourself? internetautomar?, mr gone, jeff92SE?

 

5ltr beater... do NOT change your exhaust! It's a waste of cash. I still don't get why you want a good catback but then you have a cutout. The reason people get cutouts is to be quiet... not to be loud.

I have a 2.5" Ypipe with 2.5" testpipe with 2.5" cutout. I got FASTER with the cutout. But not much faster b/c it's such a small change in power. You will lose low end and gain more top end back. So overall, you are faster.

Dont' worry about spending money on something that won't make a difference in the 1/4 mile. The Bpipe won't make any difference other than altering your powerband. Moving it up or down. It will change the noise level the most. I would stick with what you got and stop spending money on a Bpipe that is not going to make you faster.

*edit* Also, you won't be able to dyno prove the loss in low end power with your automatic. You can't rev that low in 3rd gear. But you will see a gain in top end power. I have noticed a gain of .15 in the 1/4 mile everytime I go to the track to compare.

 

I was thinking the same thing, but when i get on it from a dead stop, (this might sound crazy) it feels as though the car pulls harder when i have the cutout closed.

 

Of course it's going to feel faster!! You have gotten all that exhaust velocity back and have gained that low end torque you need to calibrate your butt dyno.

The car will FEEL slower with the cutout open. But get to the track like I've done a BILLION times and you'll see you've gained overall HP.

 

Well, my torque converter from edge racing is going in this weekend. I guess i'll wait to get that pipe and see how the torque converter improves my low end first.

 

Oh cool, you got a TC!! That's awesome! Did you talk to Andre? I wonder how he's going to set your stuff up. I bet it might be close or identical to what I have. My stall went from 1800 to 2500rpm on my tach.

 

thats weird, yeah; i spoke to andre, i told him my mods and and i told him that my car is a daily driver but i want to take off when i want to. I also mentioned that i would be extremely happy if I could see at least a 1/2 mph in the 1/4. he said that I would no prob. but again, anything can happen.

 

How is it wierd? I went with Andre to build my TC in Simi Valley b/c they were the best in the nation. Or one of the best.

It's possible for a TC to give you more top end. It's possible for a TC to give you less top end. It's just what you want. What he will do is increase the STR so you will multiply more torque off the line. Then he will increase the stall for daily driving capabilities... probably between 300-700rpm raise in stall. I am VERY curious what raise in stall you get when you get it installed. Also, I hope you have a way to keep an eye on those tranny temps. And you better have a tranny cooler.

I hope you have or are getting a VB mod soon. www.maximumtuning.net Talk to Jeff, that's the guy running the place.

*edit again* Oh yeah, next time you drive you car, find out what is the highest you can raise your stall with the brakes held in FIRMLY. Find out the highest stall you can reach without the car moving an inch. For me, my stock TC was 1800rpm on my tach. Make sure you do that before you replace the TC.

 

the reason i say it's weird is because i thought they had more than 1 salesperson and i thought it was a coincidence to get the same rep. I have a tranny cooler installed and I also installed a tranny temp gauge that i bought from autometer and i installed it thanx to your pics. as far as a VB mod; I just made a toggle switch between that long silver memory stick looking thing in the engine and when I race i just hit the switch to get those "mean" shifts, but i also make sure to toggle it back since you guys said that its also an "iffy" mod; meaning that it's not totally always safe. I thought that you had the same mod on your car. i take it that u went ahead and bought the actual VB?

 

Check out my website. I spend a lot of time keeping it up to date. Yes, I have a Max Tuning VB mod. I have never tried unplugging the drop resistor. I think it's an iffy thing to do. But Jime hasn't had any trouble with it and he swears by it. So I can't possibly have anything constructive to say on the whole "drop resistor vs VB mod" debate. But for me, I wanted a safe and reliable way to permanently quicken my shifts. So I got a VB mod. And plus, that was before the whole drop reisistor thing got popular.

Edge Racing is a small company and everything goes thru Andre... the man! It's best to talk to him straight out. I don't think he would have it any other way. This company is HUGE on 100% customer satisfaction and I am one satisfied customer.

 

So what gives better low end 2.25 or 2.5?

 

I say it's not the effort to type out the question in this forum b/c we are talking about 1 or 2 hp here!

If you want good drivability, then stick with the stock muffler and stock Bpipe (2.125" ID). If you want to gain 2 hp, then go with a 2.5" Bpipe. If you want to gain 2 more HP, then change out your muffler to a straight thru design so you can join the rest of the ricers on the road and have a loud muffler.

So to officially answer this question, I vote for "leave the Bpipe alone".

Oh yeah, to answer 90maxgxe's question, when only giving me the choices of 2.25" and 2.5", "what gives better low end?"... it's definitely 2.25"! But I the stock Bpipe will give the best low end power. But once again, Bpipes are a waste of money since you are messing with 2hp here.

 

1. Never heard a greddy before?
2. Test pipe + stock catback = horrible resonations on deceleration.
3. Dyno's of Stock vs. 2.25 vs. 2.5"? How do you know its not more than 2hp

whats up Aaron

 

Nobody up here can say that their car got noticably faster by changing out their Bpipe. Also, it's proven that a 2.125" Bpipe will give better low end power than a 3" Bpipe. Get my point?

I never said the word testpipe, so why are you bringing that up? But yes, testpipe = terrible sound.

Greddy? what about a Greddy? It's louder than stock. Simple as that!

 

Simply put, y pipe with b pipe and 5th gen muffler is the bestest sounding exhaust

 

with a resonator.....

without one can make some funny noises.

 

I have a warpspeed y pipe with 2.5 inch pipe back to the greddy mx muffler with no cat or resonators i am happy with it and i dont feel a loss of power.

 

Is urs a 5 spd. or auto?

 

hi,

his must be a 5 spd,