How to gut your primary cats (Dyno results to come soon)
09-24-15, 08:07 AM
#166
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09-24-15, 12:40 PM
#167
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Thanks for the link! This should spur more conversation between aftermarket headers producing around 400 whp and the gutted cat method in your case producing the same amount of power!! Impressive.....
09-24-15, 01:30 PM
#168
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I'm not at all surprised to see gutted stockers matching/coming close to shorty aftermarket header gains.
09-24-15, 02:43 PM
#169
09-24-15, 05:57 PM
#170
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Oh, I ain't stirring up trouble for nothing. These are in the garage right now. Details later on my silly idea. Winter time ish after I finish my 4l80e rebuild.
Attachment 492753
Attachment 492753
10-10-15, 11:38 AM
#172
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only when the windows are open. you will smell like you was racing motorcycles all day lol .
10-10-15, 12:09 PM
#173
You just described the car I've had for 6 weeks perfectly... smelly with the windows open - betting i have gutted cats on what i was told was a completely stock car. Are people seeing actual gains from this?
10-10-15, 02:07 PM
#175
Last edited by Sylvan; 10-10-15 at 10:57 PM.
10-10-15, 02:08 PM
#176
Yes you can smell it, every catless car I have rode in has had a slight fuel smell. I typically only notice it when I was accelerating hard stop light to stop light if I get caught at a red you can smell it. Initial start up when the car does the high idle (heats cats even though no cats are present) it's not a bad smell it's fairly light I bet non-cars wouldn't notice it or know what it is. I have never had a friend ask about it but my wife knew I gutted the cats before I told her because she has spent the last 20 years riding in cars with no cats
11-25-15, 06:39 AM
#177
Driver School Candidate
I too was curious as to the performance gains by gutted cats so I did a test at VIR. First trip was in May and bone stock; while second trip was in November and gutted cats. With the gutted cats I picked up 4mph on the backstraight (154mph) and reduced my lap time by 2.5 seconds. Same tires but slightly colder conditions in November.
I am using the RR Racing O2 simulator and it worked flawlessly. I gutted the primaries on the car and cut windows in the secondaries to remove the material. Then I welded the window back in and that worked well. A little smell but very little sound increase. Also my gas mileage seems to have increased. Of course this is on my spare exhaust only for track days.
I am using the RR Racing O2 simulator and it worked flawlessly. I gutted the primaries on the car and cut windows in the secondaries to remove the material. Then I welded the window back in and that worked well. A little smell but very little sound increase. Also my gas mileage seems to have increased. Of course this is on my spare exhaust only for track days.
11-25-15, 07:54 AM
#179
I too was curious as to the performance gains by gutted cats so I did a test at VIR. First trip was in May and bone stock; while second trip was in November and gutted cats. With the gutted cats I picked up 4mph on the backstraight (154mph) and reduced my lap time by 2.5 seconds. Same tires but slightly colder conditions in November.
interesting results
11-26-15, 10:40 AM
#180
So after reading this entire thread, I am still left contemplating Sikky headers or gutting the primary cats on the stock manifold. For a daily driven car, I assume you will see a difference in the butt dyno as I have the Joe z exhaust on the car already?
Can you cut the primary cats off and have a shop fabricate a pipe to replace vs gutting them?
Can you cut the primary cats off and have a shop fabricate a pipe to replace vs gutting them?