My Personal Analysis on Stock vs. Cat-less

[SHOracer14]

I've had the privilege of "borrowing" a cat-less y-pipe off of a friend for track use and got to leave it on the car for about a month. Last night we finally switched our y-pipes back. Here is my personal opinion on the pros and cons of each on a stock SHO.
Stock Y-
Pros- Awsome low-end power
Very Quiet so I am able to hear those secondaries roar
Cons- I still don't understand the 90' Angle off the rear bank (on MTX's) but this probably attributes to the low-end grunt.
Mated with a modified SHO will probably choke some power out of what could be gained.
Seems to choke the motor a bit at high revs.
It's stock so it's quiet and loud exhausts are cool.
Cat-less Y-
Pros- Awsome midrange to high-end grunt.
Adds a nice exhaust note until you really get on it and then there is some annoying rasp even with a larger resonator and turbo mufflers.
Won't choke a modified car which could probably make up for the low-end loss with it's mods.
Cons- Man the loss low-end was like night and day to me. The first time I gunned it with the stocky back on the tires ripped were as with the cat-less it felt like forever to get to 4000 to open up them secondaries.
Made the exhaust loud enough to were I had trouble hearing those secondaries roar to life.

As you can see on a stock SHO a Cat-less vs. a Stock Y end up about dead even. What the Cat-less gains in the high-end it loses in the low and vise versa. A cat-less y is a good first mod for somone to build apon but I can see myself getting a 3.2 swap and many other things before worrying about getting a catless y-pipe. I should have exact numbers in a week or so on if I gain or lose when I go to the track with the stocky back on. Let me know what you guys think. Am I totally off base with some of these assumptions or is this pretty much right?? Without numbers yet I can't prove much. When I first had the catless put on I was like holy sheet look at that tach climb but when I put the stock back on I was like holy geez she sure can get off the line now.

 

[Groo]

Any low end loss you might have experience was either imagined, or not due directly to the catless Y pipe. It's not supposed to produce any low end loss over a stock Y. The only low end lost is when comparing a catted aftermarket Y to a catless aftermarket Y.

 

[Slo-Sho]

I agree, that 90 degree bend is nasty.

 

[IT-Purrrs]

Jim are u talking about a stock y-pipe with the cats removed, or are you talking about a performance y-pipe with a better bend in it with the cats removed and not removed?

 

[AutoSHO]

What size was the piping on the Y-pipe? If it was the ATR 2.5", that would explain a lot.

 

[qiksho]

I've had the privilege of "borrowing" a cat-less y-pipe off of a friend for track use and got to leave it on the car for about a month. Last night we finally switched our y-pipes back. Here is my personal opinion on the pros and cons of each on a stock SHO.
Stock Y-
Pros- Awsome low-end power
Very Quiet so I am able to hear those secondaries roar
Cons- I still don't understand the 90' Angle off the rear bank (on MTX's) but this probably attributes to the low-end grunt.
Mated with a modified SHO will probably choke some power out of what could be gained.
Seems to choke the motor a bit at high revs.
It's stock so it's quiet and loud exhausts are cool.
Cat-less Y-
Pros- Awsome midrange to high-end grunt.
Adds a nice exhaust note until you really get on it and then there is some annoying rasp even with a larger resonator and turbo mufflers.
Won't choke a modified car which could probably make up for the low-end loss with it's mods.
Cons- Man the loss low-end was like night and day to me. The first time I gunned it with the stocky back on the tires ripped were as with the cat-less it felt like forever to get to 4000 to open up them secondaries.
Made the exhaust loud enough to were I had trouble hearing those secondaries roar to life.

As you can see on a stock SHO a Cat-less vs. a Stock Y end up about dead even. What the Cat-less gains in the high-end it loses in the low and vise versa. A cat-less y is a good first mod for somone to build apon but I can see myself getting a 3.2 swap and many other things before worrying about getting a catless y-pipe. I should have exact numbers in a week or so on if I gain or lose when I go to the track with the stocky back on. Let me know what you guys think. Am I totally off base with some of these assumptions or is this pretty much right?? Without numbers yet I can't prove much. When I first had the catless put on I was like holy sheet look at that tach climb but when I put the stock back on I was like holy geez she sure can get off the line now.

I agree with you 100% I had a catless bondourant y-pipe on my 91 plus for a few months. I really missed my low end torque as I only drive the car in the summer...and pull my jet ski's. Thus I am in the low end alot more than high. after afew months I couldn't stand the loss and the extra rasp. I enjoyed the high end extra gain...but for me it wasn't worth it. My next y-pipe will be a p-plus y-pipe with cats :****:

 

[F-22 Raptor SHO]

Couple of things for you guys to consider: I being a catless Y person have adjusted the car to compensate for the "perceived" low end torque loss.

1: As to the rasp: I have the dynomax cat back and the resonator that comes with it. Yes it rasps....between 35-45 hundred. Is it annoying? Yes. ANSWER: get an 18 inch magnaflow resonator and you will see a big difference).


2: Low end torque. I have a Ted Chip in my car that compensates for the lowend torque loss that is caused by a lean condiditon created due to the increased efficiency of the exhaust flow. At low rpm the stock exhaust is plenty efficient already and gases exit the motor and thru the exhaust just fine. Open the exhaust up and you find the gases are leaving so good that it takes some of the entering fuel out with it creating a lean condition in the cyl. Richen it up a tad and you will see you actually have more low end torque than you had before. (Im sure if Ted reads this message he will be able to offer more as well)>

Some day I will be able to test this by running the car on a dyno both with and without the chip to prove this. Without the cats and with the chip, my car runs like demons that are fleeing the blood of Christ (thats fast).

 

[Chris Benvie]

I also would like to beg to differ. When I went from stock catted ypipe/borla to the bondurant pipe/borla, I noticed ALOT more power. (this was not on the s/c 92, 95 MTX)

I do feel as if this is just a figment of your imagination, the ATR pipe, or you car has something wrong with it, somethings not right there.

 

[SHOracer14]

As far as the low-end loss I would agree and have to probably attribute it to a lean condition. As I stated above I'm not saying that a Catless Y is a bad mod it just isn't my first choice as it works better with other supporting mods (i.e. LPM). When it was down low it just felt as though the car struggled to get RPM's until the secondaries opened. I'm not sure what it could be as there are no problems with the car and it runs pretty darn strong. I think my track times SHO that the mechanicals are still in great condition. To answer your question Chris (It-Purrs) the Y-pipe is completely catless and was built by Justin Becker. It looks just like all of the other aftermarket Y's. It utilized the same diameter as stock since the cats were just cut-off and the 90' bend replaced with a better design. BTW this was built to the highest of quality as Justin very analy (is that even a word) measured exact dimensions so it would bolt up perfectly and it does. I'll probably have him make me another one down the road but I am waiting to get my 3.2 rebuilt as well as a few other goodies added. I gotta at least keep up with Beth as she seems to be the fastest white plus that I know of.

 

[Chris Benvie]

AHH a home made pipe, that would make sense in some ways.

 

[PROPHET]

I think stock performs better than aftermarket catless, now aftermarket with cats is a different story.

 

[shojuan]

I think a good way to address the rasp issues with the catless y-pipe is to pick up some highflow cats cheap on ebay. At under $100 for a pair it's going to do more for the exhaust note, stink, and environment than a fat resonator will. Too many people have gone through the process of trying all sorts of different resonator combinations to improve the exhaust note. It's just too bad that the $33 a piece magnaflow cats on ebay that were available everyday for over 6 months are no longer there (at least they weren't last I checked many months ago). Last time I checked, the best price was $44 a piece.

 

[Speedy_91_SHO]

I agree with everything said in this thread so far. I am the one that switched Y's with him. With this particular pipe, there is a loss of low end torque. On the otherhand, the mid-high end power all but makes up for the loss of low end torque. In the rain, I can lose traction up to third with the stock pipe. With the catless however, I can lose traction in 4th also. I also do realize that this can be changed with a chip and other supporting mods which I am working on.