SHould i get a high flow cat?

[Blazingwolf]

I have headers, y-pipe, and greddy sp2 cat back. my cat is backing up cause my greedy pipe is turning purple.should i just get a stock cat or a high flow cat??? im worried about power loss since ive never done one and im not sure how this car handles loss of back pressure..

96 maxima 5 spd

[nismo1219]

just get a high-flow cat...even if you loose a bit of hp, it wouldnt be enough to notice any differences.

i have headers, y-pipe, high-flow cat & magnaflow can...i havent ever had any issues out of my setup.

[Blazingwolf]

sweet. did u lose any bottom end power? i kinda figure that i'll lose bottom end and gain top end

i have a place i can test my launch speed and top end. so i'll let you know the benefits if ur interested

[nismo1219]

sometimes, i can feel it dragging a bit off the line...but that's not common enough to it be an issue...however it does seem to pull a bit more thru the higher rpms, especially in 2nd & 3rd gears.

btw - im an automatic, unfortunately

[allensteiner]

less back pressure = more power. the bottom end loss is the result of the aftermarket y-pipe so even if you go with a test pipe you will be actually gaining instead of losing power.

[Blazingwolf]

true allen, but some ecu's don't know how to register the loss in backpressure and try to make changes to the A/F ratio due to the change of flow which can result in a loss of power

GREAT EXAMPLE:Dodge srt-4 neon loses 40 hp when the cat disappears because of low backpressure

[jltibbs]

my cat is backing up cause my greedy pipe is turning purple.

I don't think your cat is backed up. You would be seeing major loss of power with a downshift at higher speeds. Plus you would more than likely have a CEL on. If not, then your cat is fine. The most likely reason for your exhaust turning colors is oils. If you or whoever installed them without gloves, then there's where your discoloration is coming from.

[Blazingwolf]

new info.. i had forgotten about this. the operating temp for cats is between 800 and 1600 degrees.. cats don't work unless they are hot. that's why ur computer doesn't monitor them while ur car is warming up.. stainless steel turns colors above 270 degrees.

oh im still getting a high flow cat.. im hoping for a top end gain

[jltibbs]

stainless steel turns colors above 270 degrees.

oh im still getting a high flow cat.. im hoping for a top end gain

Agreed on the color change, but, stainless should bronze. When I installed my headers they turned a nice bronze color. My mechanic and I used gloves on them. One day some idiot put his finger on my header and I did not realize it until I ran the motor. So, I had one blueish purple fingerprint on my front header.

If you want more top end gain, get a light weight pulley.

[Blazingwolf]

yeah my headers are a golden color. i had an altima that ran lean and mean and its headers were blue and i had forgotten about this. its just the heat and i think i will get a pulley

[jltibbs]

Pulleys are the way to go bro.

[Blazingwolf]

they only make an underdrive pulley for the crank.. do you know why that is?

[nismo1219]

i think i will get a pulley

The only choices for pulley's that I know of for Maxima's are either an "underdrive pulley" or a "light-weight pulley." The underdrive pulley is a smaller diameter than the stock pulley and will "underdrive" your electronics and will help get the rev's up much quicker. The light-weight pulley is the same diameter as the stock pulley but being lighter uses less rotational mass and thus spins quicker as well. I'm not sure about which would give better gains, I would assume they would be pretty close to the same. I have an Unorthodox underdrive pulley on my Maxima, so did Jeremiah.

http://www.unorthodoxracing.co...ory=2

[jltibbs]

I had the crank pulley, not the underdrive. I thought I was getting the underdrive until we went to put it on and I realized they sent the crank. Still got a great response.

[nismo1219]

My bad....

[Blazingwolf]

so you would say it was worth it then? i was skeptical about getting it. i can't get the underdrive cause i have a huge stereo.. so the lightweight one helped ?

oh im bout to buy a mevi cause i don't have the time to do an 00vi

is there anything i should know about one or how to install it.i know there are a couple things to buy, where might i find them?

[jltibbs]

Common misconception on the car audio, bro. Forget about your alternator when it comes to the system. There are other things you can do in order to have sustained power while being a negligent audiophile. Use, as a rule of thumb, one 1 farad capacitor for every 250 watts. Do this and you will have no issues bro. Get the under drive, as you will see more gains from it on the 5MT. You will see a slight gain from the lightweight crank pulley, but not near as much as the under drive. Get what you want and make adjustments elsewhere.

[nismo1219]

Yeah, I would recommend it if your wanting to help increase performance...every little bit helps! I dont know crap about the audio but I know the underdrive really didnt affect anything much. All I notice is that my gauges dim for a slight second when i tap the brakes...which may have been there before the underdrive pulley was installed and I just never noticed...LOL.

[Blazingwolf]

haha i got 1200 watts and only 1 farad cap.. i did however put a huge 950 cold cranking amp battery in for the old standard nissan one.. my lights...DON"T DIM

so i will try the underdrive pulley. if it doesn't work out then i''ll change it. but i don't keep it up all the time so my battery should handle the load

[Blazingwolf]

i took the cap out. it was pointless.. the underdrive is on its way and the high flow cat from Random Technology is awesome! very good quality piece of equipment. power was gained. i have a spot that i run. stock speed was 100 mph. headers and k&n was 105headers k&n +cat-back was 110headers k&n +cat-back and HFcat was 113 on warm air @70 degreesprevious runs were at 48 degrees