Gut Rear Pre-Cat Suggestions
09-20-2011, 02:20 PM
#1
Gut Rear Pre-Cat Suggestions
So currently, the front pre-cat is gutted on my car. The mechanic ran out of time today and couldn't tackle the rear.
Some have mentioned gutting the rear pre-cat with it still on the car.
According to the mechanic, the catalyst material seems to no longer be stationary, but is instead moving as a whole piece when he tries to break into it (he said this was the case before he tried breaking it).
He doesn't think any of the air tools can reach far enough so that the catalyst material can be pushed against the 'headers' so that it will break apart.
Short of taking the rear pre-cat off the car, does anyone else have any ideas that can help? Tomorrow's the last shot at getting it done.
The only issues i've had with cats was with the front pre-cat in terms of obd2 codes.
Would leaving just the front gutted cause issues?
Some have mentioned gutting the rear pre-cat with it still on the car.
According to the mechanic, the catalyst material seems to no longer be stationary, but is instead moving as a whole piece when he tries to break into it (he said this was the case before he tried breaking it).
He doesn't think any of the air tools can reach far enough so that the catalyst material can be pushed against the 'headers' so that it will break apart.
Short of taking the rear pre-cat off the car, does anyone else have any ideas that can help? Tomorrow's the last shot at getting it done.
The only issues i've had with cats was with the front pre-cat in terms of obd2 codes.
Would leaving just the front gutted cause issues?
09-20-2011, 02:23 PM
#2
Take off the rear precat. You'll thank me later. It should be a cake walk for your mechanic. They have a lift, right?
Two words to answer your question about facilitating the job. Tungsten-carbide. Drill.
Two words to answer your question about facilitating the job. Tungsten-carbide. Drill.
09-20-2011, 02:30 PM
#5
09-20-2011, 03:35 PM
#8
A mechanic with air tools should have no problem doing this job, I did it with hand tools and a drill and sawzall, takes a long time, and is a B1tch of a Job hated it, glad im getting my Headers....
09-20-2011, 04:37 PM
#9
Yeah with them on the car its a real head ache of a job, I did it with a flat head screw driver that was nice and long and big, a big drill and bit plus a chisel. It took forever but once I got enough room to wiggle pieces around it got easier
09-21-2011, 05:33 AM
#11
Senior Member
Join Date: Apr 2011
Location: Ontario, Canada
Posts: 539
09-21-2011, 05:52 AM
#12
I think that's kinda the point though brl24. We're trying to remove the cats.
Interesting idea gatsugan.. I wonder if that'd work without having to ignite the acetone.
Anyone have any insight?
Interesting idea gatsugan.. I wonder if that'd work without having to ignite the acetone.
Anyone have any insight?
09-21-2011, 06:41 AM
#14
Not only that, but it will pour and then go through the cat, end up somewhere below the cat, the floor if the pre-cat is d/c'd from the rest of the exhaust and evaporate in about 5-7 minutes TOPS if it doesn't start a fire along the way.
09-21-2011, 07:24 AM
#15
Tomorrow would be today, so whatcha doing, OP... leaving it as-is, gutting it on the car or gutting it off the car?
I'm kind of curious, but mostly I'm collecting gutted precat threads. And let me tell you, it's hard to keep up!
I'm kind of curious, but mostly I'm collecting gutted precat threads. And let me tell you, it's hard to keep up!
09-21-2011, 04:09 PM
#16
He got it out. Don't know how he did but he did it while I was stuck in jury duty.
When I drove the car yesterday, I actually had a hole or something in my muffler and the sound difference was pretty noticeable.
He patched it up for me and now its quiet again. Haven't had much time driving it (8 minutes tops in philadelphia city traffic) so I'm still feeling it out.
Did a little first gear pull and it felt like it pulled much harder. This could be because of the issues i've been having with it lately (MAF went bad a week and a half ago, cats possibly clogged, hole in the exhaust) but it pulls harder than I remember it ever did.
Glad to see the CEL gone too, which is a big big plus. Best thing about it is, most people out there still think the car's stock w/ an intake and won't be able to tell cause all I have now are SRI, BOP, IM Spacers and gutted cats. Most noticeable thing obviously being the SRI.
Next step is to see how fuel economy is.
When I drove the car yesterday, I actually had a hole or something in my muffler and the sound difference was pretty noticeable.
He patched it up for me and now its quiet again. Haven't had much time driving it (8 minutes tops in philadelphia city traffic) so I'm still feeling it out.
Did a little first gear pull and it felt like it pulled much harder. This could be because of the issues i've been having with it lately (MAF went bad a week and a half ago, cats possibly clogged, hole in the exhaust) but it pulls harder than I remember it ever did.
Glad to see the CEL gone too, which is a big big plus. Best thing about it is, most people out there still think the car's stock w/ an intake and won't be able to tell cause all I have now are SRI, BOP, IM Spacers and gutted cats. Most noticeable thing obviously being the SRI.
Next step is to see how fuel economy is.
09-21-2011, 08:17 PM
#18
When I said IM Spacers, I meant the NWP phenolic spacers
09-22-2011, 05:49 PM
#19
Member
Join Date: May 2009
Location: Arcadia, CA
Posts: 206
Congrats on getting the precats gutted. I did my rear while still on my car. I had to lay on my back with a drill while a buddy of mine held a wet/dry vac sucking out all the dust before it would go up into the exhaust manifold. Total pain!
09-23-2011, 01:31 PM
#20
yes I meant by using the spark plug anti foulers...whats your gasmileage b4 and after
09-23-2011, 06:39 PM
#21
well I'm in the middle of a tank right now so I won't count it.
Usually i get around 27 mpg on my way to work and if i do more city driving, round 25.
I check every fill up so I'll see if there are any noticeable differences.
As mentioned in other threads, there's really no sound difference that I noticed after gutting the cats
Usually i get around 27 mpg on my way to work and if i do more city driving, round 25.
I check every fill up so I'll see if there are any noticeable differences.
As mentioned in other threads, there's really no sound difference that I noticed after gutting the cats
09-23-2011, 07:56 PM
#22
well I'm in the middle of a tank right now so I won't count it.
Usually i get around 27 mpg on my way to work and if i do more city driving, round 25.
I check every fill up so I'll see if there are any noticeable differences.
As mentioned in other threads, there's really no sound difference that I noticed after gutting the cats
Usually i get around 27 mpg on my way to work and if i do more city driving, round 25.
I check every fill up so I'll see if there are any noticeable differences.
As mentioned in other threads, there's really no sound difference that I noticed after gutting the cats
10-02-2011, 05:53 PM
#23
So for an update for whoever cares.
In my last fillup, I got 25 mpg. It was both city and highway driving.
Things to consider:
I usually use 93 octane.
For this particular fillup, my MAF sensor had an issue and I guess I was just fed up with the steady stream of problems for the last month leading up to it so I used 89 octane.
Car seemed to drive fine and still had plenty of power (moreso than before) and I was able to get 25 mpg.
I was beating on the car a little more than normal (I almost never do), just to 'make sure the MAF issue was fixed' and to see if I wasn't just imagining that the gutted cats made a difference in power.
Now, my MAF issue is fixed and I'm once again running 93 octane gas. I'll update in a week what the fuel economy is for a more 'controlled' number. (normal gas I usually run and no MAF issue).
In my last fillup, I got 25 mpg. It was both city and highway driving.
Things to consider:
I usually use 93 octane.
For this particular fillup, my MAF sensor had an issue and I guess I was just fed up with the steady stream of problems for the last month leading up to it so I used 89 octane.
Car seemed to drive fine and still had plenty of power (moreso than before) and I was able to get 25 mpg.
I was beating on the car a little more than normal (I almost never do), just to 'make sure the MAF issue was fixed' and to see if I wasn't just imagining that the gutted cats made a difference in power.
Now, my MAF issue is fixed and I'm once again running 93 octane gas. I'll update in a week what the fuel economy is for a more 'controlled' number. (normal gas I usually run and no MAF issue).
Last edited by OnOiShNo0dl3Z; 10-02-2011 at 05:58 PM.
10-02-2011, 09:41 PM
#24
wow 25mpg, thats great... I get abt 21 and Im auto stock. How are the spark plug spacers working for you in the primaries? any cel since you got everything done? I rele want to gut my precats now
10-03-2011, 05:09 AM
#25
The 25 mpg is pretty similar to what I got before gutting them. However, I was using 89 octane gas instead of the usual 92 or 93 (depending on where I get it) and I was probably beating on it a bit more. Also had a bad MAF issue at the beginning so hopefully the number improves with these factors taken out.
As for the CEL, before I reset the codes, I had a CEL for the bad MAF and it also still showed for the p0430.
After resetting the ecu, I only saw codes for the MAF. After I fixed that, no more CEL.
It's been off for about a week and a half now. I'll try and update on that again after a month or so (a month was the longest I went with the CEL off in between the intermittent p0430 codes)
As for the CEL, before I reset the codes, I had a CEL for the bad MAF and it also still showed for the p0430.
After resetting the ecu, I only saw codes for the MAF. After I fixed that, no more CEL.
It's been off for about a week and a half now. I'll try and update on that again after a month or so (a month was the longest I went with the CEL off in between the intermittent p0430 codes)
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