i removed my cat a week ago and i was wondering if it added any hp and about how much, thanxs

 

Removing any exhaust restriction will free up power, especially the cat. I'm not sure how much power you gained, but probobly nothing that you would feel in the seat of your pants.

 

I dont want to hear any crap about this just look it up yourself if you want. In either august, september, or octobers issue of car craft they put i think there 91 Z28 project car on a dyno with and without the cat and it was a 1 horsepower difference. I dont know if it was an aftermarket highflow cat but if it was you should just get one and keep your car emissions legal.

 

well their is another side. if you cat is old and pluged up you might gain something but the fact that you are asking this question tells me you must not feel the differce. soif you do something and can't feel the differece chances are it is not much.

------------------
"I don't trust anything that bleads for five day's and doesn't die"
88 iroc slp headers,borla catback,procharger to come soon.

 

here's some info I posted in another thread if you're interested.

I've got news for you all. My friend shawn had one of those 3" high-flow cats and it killed over 100hp. He hollowed it out and gained more than 10 MPH recorded vericom trap speed. He was then running low 12's after that.
questions, feel free to email him about it.
sbeach@postnet.com
ODB

setting up a dyno test to make a converter look good would be really easy.. just run the engine too lean. The converter will richen up the engine and increase torque.
I think Shawns converter may have been from Random, but I'm still waiting to hear from him on that. I will post it when he tells me.

ODB

here is Shawn's reply, I just got it.
"Thrust 3" by 3" high flow. it cost $100. I now why my car lost so much
from
it. I had iron heads on the car at the time at had to run rich just to
keep
it from knocking. I believe a car running rich like that will lose a
****
load more compared to a car running lean. The car would spark knock
when i
put that ****ing thing on and ran 220 deg campared to 160."


ODB

He was making over 350hp at the rear wheels with that engine.

 

Who cares about the cat, wouldn't it sound better without??

 

Why would they set up the test to make the converter look good i dont think they even said whos it was so it wasnt a sponcer. It was a test to show people how much hp you gain by removing the cat. Not a test to make you buy a specific one.

 

oh yeah,
it was the Car Crap*(tm) "project" car.

 

something else that test showed was that you lose torqe by removing the cat

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1991 banditt2 #130 of 600
Project 350 TPI Banditt2

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When I bought my car, it didn't come with a cat. It sounded very nice but I had to put one on to pass emissions. After putting it on, it muffled my sound but felt as if it actually increased my torque! I'm pretty sure that it has something to do with proper backpressure. It's alot like the exhaust cutouts, they really aren't good if you don't rev your motor to like 4000 rpm because lack of backpressure hurts your torque.

Chris

 

My friend ran his 3.1 Lumina at the track and ran a 16.6 with just a turbo muffler and K&N. The next time we went, we ripped off his cat and made a cold air, intake. His 1/4 mile time with no cat, turbo muffler, and cold air intake, he achieved a time of 16.1.

 

So basically by removing the cats, you would gain in horsepower but not by much and you would lose torque. So its like one of those give and take situations. Hhhmmm, well now I have some serious thinking to do. I was going to remove my cats so I can get more clearance under my car but now I'm kinda of skeptical bout it. My car is really strong off the line so I dont know if I'm willing to sacrifice the torque just for clearance. And the random tech cats are just way too expensive. Oh well.

------------------
SS 17x9.5 wheels,
HOTCHKIS 1"drop springs,
HOTCHKIS tower brace,
Bilstein struts and shocks,
K&N filters,
MSD 6A,
MSD 8.5mm Wires,
MSD Cap & Rotor,
Hypertech airfoil,
SLP intake runner (plennum not ported yet, soon)
High flow cats,
SPOHN panhard bar, lower control arms, and subframe connectors,
Baer front track system,
3" Flowmaster Exhaust System,
2100 Stall High Performance Torque Converter,
300 watt sound system,
and soon to come...ZZ4 crate motor...hopefully.

 

My friend has the same car as I, and he still has his cat. we ran at the track last season, and even with my headers he was only .1-.2 secs behind, which could account for the headers.
Also, he has a sh*tload of torque off the line, and the car feels MUCH faster, but it doesn't seem to pick up much on the high end like me.
I'd say you lose 20 lbs/ft of torque to gain 2 hp.
But as far as sound, no cat sounds much louder and meaner.

Brandon

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White '92 Firebird w/ 305 TBI. Open element w/ non drop base, increased fuel pressure, TBI spacer, Hedman Hedders & y-pipe, no cat, cat-back exhaust

 

I just put a new cat on after running the better part of a year without due to the old one being plugged up. The results from the straight pipe were louder and better sound and much better performance. With the new cat yesterday,the sound is quieter(bad) and the performance is unchanged. After I pass the test next week I'll have it back off until next year.