No Cats. Robes H.P.?

[cryptic]

No Cats. Robs H.P.?

I'm tired of hearing that no cats. rob backpressure in turn causing you to loose low end h.p.....Some one either re assure me that the loss is minimul or correct me and flam on

I'm asking because I will replace my -x- for a pro-chamber in a few weeks!

 

[fatkidracing4.6]

OK i have always built my cars by this philosophy is the key to power is the more air in and the more air out! there is no way that no cats are hurting you in power! I am not even going to run an x pipe! i am going to do true duals, but as an interesting note i am going to dyno before and after and i will let you know what i find!

 

[Sick96Stang]

Yes cats will rob you of low end power but you will gain it back up top. This dyno graph is off a stock 01 Cobra, tests were done by mustangexhaust.com
If you are worried about low end lose get a nice chambered muffler that will help you keep some of the low end power and the O/R mid-pipe will help you up top, best of both worlds

 

[Modular2v]

OK i have always built my cars by this philosophy is the key to power is the more air in and the more air out! there is no way that no cats are hurting you in power! I am not even going to run an x pipe! i am going to do true duals, but as an interesting note i am going to dyno before and after and i will let you know what i find!

just thought you should know that a 4.6 stang does come with true dual exhaust.....

 

[Sick96Stang]

just thought you should know that a 4.6 stang does come with true dual exhaust.....

I think he means hes not going to run a mid-pipe. Hes just going to run straight pipes, IDK how well that will work but hey its not my car.

 

[Jinx]

just thought you should know that a 4.6 stang does come with true dual exhaust.....

I think he's saying that he's planning on running separate exhaust for each side of the exhaust manifold.

fatkidracing4.6 you may want to do a search on this idea before doing it because there is a reason for equalizing the pressure via midpipe. Not sure why, maybe someone here knows.

edit: posted the same thought, just a little slower

 

[Modular2v]

i would think a cross over pipe would be better than an individual pipe running straight back for each side.....the crossover would help equalize backpressure

 

[timeless2]

i would think a cross over pipe would be better than an individual pipe running straight back for each side.....the crossover would help equalize backpressure

+1

 

[hognutz]

got to love the internet. people do not really compare apples and apples.

one thing that no one seems to take into account is stock is 2.25 and almost all aftermarket is 2.5. so the loss of torque is attributed to the cats and not the pipe diameter.

so you are comparing apples and oranges. the low end power loss could be coming from the larger diameter pipe tuning the power up in the band.

I would bet that a full mandrel 2.25 exhaust with no cats would proably yield a more desirable cure on a completely stock car with no other mods than a 2.5 system. once you start adding more mods though the 2.25 would becomes a restriction as well.

As to running true duals it is a step backwards. a crossover gives the exhaust a better scavaging effect. they don't put them there to hurt power.

the correctly placed X pipe will proably alwasy yeild the most desireable power.

 

[RedBullitt]

put a darn x on there and you will not be dissapointed, catless or not. you dont really lose anything, its more of a trade or move of power. you lose some down low, but you gain more higher in the rpms

 

[Blue35thGT]

I gained both in HP and TQ...

 

[CaliLifeStyle]

Gears should make up for the loss of power in the low RPM's.

 

[AdRock]

I gained both in HP and TQ...

But where in the power band did you gain it? I think that is part of the issue.

When you open up the exhaust you'll lose a little tq on the low end at take off. This is also where most of the daily driving is done so it will feel more sluggish. However, since it flows much more freely the power you gain will be on the top end. So the car will gain power in in part of the band but drop power in another. Finding the balance between the two is the key. AS said before, this can be somewhat done with a set of chambered mufflers since they are more restrictive than the flow through type.

 

[csledd]

I installed my LTs, O/R X-pipe, and cat-back all at once and I definately lost low end power, but I also definately gained A LOT up high. The SOTP meter was crazy, on cold days when I'd take the car out on the street and driving in first gear with stock gatorbacks.. if i got on it the car would loose traction past 4k. it was fun lol. When I got the dyno tune it helped throughout my whole powerband a lot. At peak I gained 13 rwhp and 22 rwtq, but in the lowend spectrum of the band, in some places I gained back 30-40 rwhp and 40-50 rwtq

 

[hotmustang331]

No, cats rob HP...not the otherway around. Back pressure promotes lowend torque, so that could be the same as going small pipe W/O cats as larger pipe with cats. But lowend torque never won any races, your best bet is to go O/R....it will make more power and will make you faster in the 1/4.

And to the guy thats not going to run a mid pipe, DONT DO THAT! You need a crossover, look at nascar they ALL run midpipes....Xs. The presure equaling gives power by not allowing pulses to go back up your exhaust...the sooner you cross overe and connect the pipes, the better.

 

[csledd]

losing low end is worth it, this is how i look at it, get some nice gears and you'll never have to worry about being down there too long

 

[posm6s]

losing low end is worth it,...

Not if you driving around in a 5000 lb brick.

 

[hotmustang331]

Thats what your roots S/C is for LOL.

 

[hotmustang331]

in some places I gained back 30-40 rwhp and 40-50 rwtq

That must have been a kick in the butt. Dang.

 

[Gray03GTStang]

I had a BBK off road (no cats) H-pipe on my 98 and I didnt lose any hp out of it actually gained more! either way you go off road or catted anything is better than stock