no cats with long tubes
Thread Starter
Pro
Joined: Nov 2004
Posts: 698
Likes: 1
From: louseyville Ky
no cats with long tubes
I am getting my EM longtubes in on Monday or Tuesday, so they say. I only ordered the headers and gaskets with the bolts. Assuming I am not running cats what is the best way to set this up. Pictures would be great. I would guess to hook up the headers and take to a shop for the rest. thanks in advance
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
and that shop would be so in deep **** if you have them bolt up the headers without cats. I would be surprised if they would do it.
Which leads to the second fact, the noise would be deafening.
Which, in turn, leads to the third fact, modern engines require a minor amount of back pressure to operate correctly...
Which, finally, leads to my preaching tirade about environmental responsibility and the low price a couple of bullet cats cost.
And don't say "it's only one car" cause if everyone did it, then we would have a massive air pollution problem.
Do the right thing - do the LEGAL thing and get some cats.
Which leads to the second fact, the noise would be deafening.
Which, in turn, leads to the third fact, modern engines require a minor amount of back pressure to operate correctly...
Which, finally, leads to my preaching tirade about environmental responsibility and the low price a couple of bullet cats cost.
And don't say "it's only one car" cause if everyone did it, then we would have a massive air pollution problem.
Do the right thing - do the LEGAL thing and get some cats.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Put in a crossover, or X or H pipe, that will kill some resonance and put in just enough back pressure to help low-end torque.
Race Director
Joined: Sep 2004
Posts: 13,793
Likes: 0
From: St. Peters MO Sometimes you have to prove yourself by doing alot of killing or alot of dying...
Originally Posted by bogus
and that shop would be so in deep **** if you have them bolt up the headers without cats. I would be surprised if they would do it.
Which leads to the second fact, the noise would be deafening.
Which, in turn, leads to the third fact, modern engines require a minor amount of back pressure to operate correctly...
Which, finally, leads to my preaching tirade about environmental responsibility and the low price a couple of bullet cats cost.
And don't say "it's only one car" cause if everyone did it, then we would have a massive air pollution problem.
Do the right thing - do the LEGAL thing and get some cats.
Which leads to the second fact, the noise would be deafening.
Which, in turn, leads to the third fact, modern engines require a minor amount of back pressure to operate correctly...
Which, finally, leads to my preaching tirade about environmental responsibility and the low price a couple of bullet cats cost.
And don't say "it's only one car" cause if everyone did it, then we would have a massive air pollution problem.
Do the right thing - do the LEGAL thing and get some cats.
I agree with a majority of what Bogus has to say. These motors don't gain all that much simply because the cats are removed. And bullet cats aren't all that expensive. It's just better to save the evironment in my opinion.
And finally... the deafening noise... well I'm still partial to the sound of open headers on a track... so I think the "noise" would be coool
Thread Starter
Pro
Joined: Nov 2004
Posts: 698
Likes: 1
From: louseyville Ky
Originally Posted by Fuzzy Dice
I won't get into laws and stuff...I will say I have long tubes running back to stock mufflers with nothing in between and the sound is all good....
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
I know that you want to run without cats however, look at the LT with CATS picts in these threads and you might change your mind.
Mike
A4s with LTs and cats
Mike
A4s with LTs and cats
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Originally Posted by bogus
Which leads to the second fact, the noise would be deafening.
I once fired up the car with just the headers on with no front y-pipe durring an install, just to see what is sounds like with open headers. It was so damn loud just idling outside my garage that the stuff on the walls where vibrating and buzzing, and I decided to not even take it arround the block. I wonder what it would sound like driving it on the street.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
I have the long tubes with out cats and it sounds quite nice. There is no resonance and it is a little deeper then stock. This was through the stock mufflers and stock resonator. Next I removed the resonator and installed 2 bullet cats where they go. Sounds about the same as above.
As far as hooking up to the stock exhaust here is what I did. I got a 3 in connector and cut the left side about 2 in short of the header. I then used a small piece of the cut pipe (2&3/4 pipe) from the left side and slid it in the slip fit on the factory exhaust on the passanger side. I then purchased a 3 in pipe about 2 ft long from auto zone and slid it on the header and then slid the 2&3/4 pipe into the end of it. I then welded the 2&3/4 pipe to the 3 in pipe on both sides and I used 3 in band clamps on the headers. It does not look that great but you cant see it unless you are under the car. If you can get a exhaust shop to do it for you they could swell the pipe ends and make for a little better flow. In my area they wont touch it because of emissions.
As far as hooking up to the stock exhaust here is what I did. I got a 3 in connector and cut the left side about 2 in short of the header. I then used a small piece of the cut pipe (2&3/4 pipe) from the left side and slid it in the slip fit on the factory exhaust on the passanger side. I then purchased a 3 in pipe about 2 ft long from auto zone and slid it on the header and then slid the 2&3/4 pipe into the end of it. I then welded the 2&3/4 pipe to the 3 in pipe on both sides and I used 3 in band clamps on the headers. It does not look that great but you cant see it unless you are under the car. If you can get a exhaust shop to do it for you they could swell the pipe ends and make for a little better flow. In my area they wont touch it because of emissions.
Le Mans Master
Joined: May 2000
Posts: 7,033
Likes: 12
I had a gutted cat and I hated it with headers and aftermarket mufflers.
Headers and a decent cat back sound good with a cat in place. For the 3-5hp you gain with no cat why wouldn't you have one?
BTW I ended up replacing my cat
Headers and a decent cat back sound good with a cat in place. For the 3-5hp you gain with no cat why wouldn't you have one?
BTW I ended up replacing my cat
Racer
Joined: Apr 2002
Posts: 342
Likes: 0
From: new orleans La
Originally Posted by hippy
I had a gutted cat and I hated it with headers and aftermarket mufflers.
Headers and a decent cat back sound good with a cat in place. For the 3-5hp you gain with no cat why wouldn't you have one?
BTW I ended up replacing my cat
Headers and a decent cat back sound good with a cat in place. For the 3-5hp you gain with no cat why wouldn't you have one?
BTW I ended up replacing my cat
What kind headers do you have? I'm not aware of any long tubes that are compatable with the stock cats or at least on LT1's
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Originally Posted by FD2BLK
My stainless headers came with the pipes already bent, call EM and see if they offer somthing similar, and I welded them straight to the existing resinator.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
You would have to tell the shop the vehicle is for off road use only . Of course, if you have no testing in your area, it may still be legal for them to remove them. IMO removing cats makes the exhaust resonance "boom" a little too much .
Thread Starter
Pro
Joined: Nov 2004
Posts: 698
Likes: 1
From: louseyville Ky
Thanks for all the advice and the pictures guys. Bogus, you will happy to know that I have decided to go the cats route. I don't see eye to eye with you on your reasoning but I respect your o2. A lot of guys are afraid to put in writing things that can be seen as not popular. Good for you for having the courage to do so time after time when this question come up. I am going the cats route to avoid the noise issue and also to be prepared if testing ever does come back.
I am going the cats route to avoid the noise issue and also to be prepared if testing ever does come back.
Racer
Joined: Oct 2002
Posts: 494
Likes: 0
From: Victoria BC
I Have EM longtubes and no cats. With the A4 I could not fit the cats. The longtubes were over lapping the Random tech cats on the corsa system. Anyway, it is louder at idle and under WOT but when crusing, it's no difference really.
