Feeler thread for stock hollowed out precats
#1
Feeler thread for stock hollowed out precats
So I decided to venture out and take a stock set of pre cats and remove the cats, thus making precat deletes. This way it also uses the stock heat shield to keep the oem look. I am just sturring up some interest as I would be offering a trade in service.
I did install these and the power gains were there and amazing. With this service I will be offering new head gaskets and defoulers for a proper install. I would post pictures but it's essentially a stock set of precats just hollow.
I am thinking $200 plus shipping and I would need your stock oem ones back with no cracks or anything less than normal use so I can trade them with the next customer.
I did install these and the power gains were there and amazing. With this service I will be offering new head gaskets and defoulers for a proper install. I would post pictures but it's essentially a stock set of precats just hollow.
I am thinking $200 plus shipping and I would need your stock oem ones back with no cracks or anything less than normal use so I can trade them with the next customer.
#2
BANNED
iTrader: (33)
got pics?
just kidding, thats a great idea bruce.
just kidding, thats a great idea bruce.
#4
Race Director
iTrader: (1)
So why wasn't this considered before. There has to be some downside, no?
#5
Safety Car
Genius.
#6
Thank you all. No downside, only up IMO because you can throw the heat shield on and keep the oem look just hollow for track purposes and create a sleeper.
Not sure why no one has thought of this. I mean it is a pain to remove the cats and clean them out. Other then that, it's a hollow tube.
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#8
Stock pre cats I've seen fail, when these cores crumble it gets sucked back into the engine so instead of buying new cats, these are also an option for you.
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justnspace (01-18-2013)
#9
06 Anthracite TL
That's a very interesting idea. I have a Toyota MR-2 and when those cars were built, the precats had a nasty way of breaking down prematurely and trashing the engine. The owners of these cars either replaced the OEM precats with a header (like I did) or took out the factory header with the precats, essentially destroyed them, cleaned out the head completely to get rid of any residue, and reinstalled the header. As a result, no further engine failures. The main cat is still in the car, intact.
The cars with precat deletes will still pass emissions (as mine has) since my header is encased in the OEM heat shields, and in NJ, it's basically an OBDII code check and driving over a camera to make sure the main cat is still there. Since the precats only help with emissions during the warm up of the engine, they really don't do a whole lot otherwise, and in this case, the decatted header will look OEM, so the emissions check should present no issue. Overall, it sounds like a good idea.
The cars with precat deletes will still pass emissions (as mine has) since my header is encased in the OEM heat shields, and in NJ, it's basically an OBDII code check and driving over a camera to make sure the main cat is still there. Since the precats only help with emissions during the warm up of the engine, they really don't do a whole lot otherwise, and in this case, the decatted header will look OEM, so the emissions check should present no issue. Overall, it sounds like a good idea.
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AckTL05 (01-17-2013)
#10
I know that the PCDs cause some rasp; do the de-cored cats rasp as bad? I would think not since they are made of thicker steel.
Are you cutting these apart and rewelding them or just knocking the substrate out from the ports?
I'd love to see a dyno comparing these with PCDs...
Are you cutting these apart and rewelding them or just knocking the substrate out from the ports?
I'd love to see a dyno comparing these with PCDs...
Last edited by gwiffer; 01-17-2013 at 04:21 PM.
#11
My first ricer
iTrader: (4)
Not trying to be a negative Nancy, as I'd probably do it myself if I thought mine were bad, but couldn't purposely tampering with OEM emissions and sending them back get you in a little trouble? It's one thing if you sell a new part as "off road only" but deliberately destroying OEM parts for a profit... just saying, if I were to do it I'd probably ask people to label it as scrap metal or something.
As far as performance, it should get most of the gain but the outlet is smaller than the PCDs. Also cars I've heard with gutted cats vs straight pipes don't sounds as good, just kinda sounds a little more hollow.
As far as performance, it should get most of the gain but the outlet is smaller than the PCDs. Also cars I've heard with gutted cats vs straight pipes don't sounds as good, just kinda sounds a little more hollow.
#12
I know that the PCDs cause some rasp; do the de-cored cats rasp as bad? I would think not since they are made of thicker steel.
Are you cutting these apart and rewelding them or just knocking the substrate out from the ports?
I'd love to see a dyno comparing these with PCDs...
Are you cutting these apart and rewelding them or just knocking the substrate out from the ports?
I'd love to see a dyno comparing these with PCDs...
Not trying to be a negative Nancy, as I'd probably do it myself if I thought mine were bad, but couldn't purposely tampering with OEM emissions and sending them back get you in a little trouble? It's one thing if you sell a new part as "off road only" but deliberately destroying OEM parts for a profit... just saying, if I were to do it I'd probably ask people to label it as scrap metal or something.
As far as performance, it should get most of the gain but the outlet is smaller than the PCDs. Also cars I've heard with gutted cats vs straight pipes don't sounds as good, just kinda sounds a little more hollow.
As far as performance, it should get most of the gain but the outlet is smaller than the PCDs. Also cars I've heard with gutted cats vs straight pipes don't sounds as good, just kinda sounds a little more hollow.
Anyone can sell things, like how they sell pre cats. It's designed for race/offload purpose. Install is on the buyer and they take the same risks as installing pre cats. I will look into it but I don't see how companies sell pre cats and headers for cars and not get in trouble. I am selling these as off road purpose and track. This is the catch 22 where some shops don't like tampering with cats and installing them, but to me I'm selling a pipe thats hollow, but ask for the stock one back from there track or off road car.
#15
Well tested it out. Not one bit of rasp, with a slight bit more throaty exhaust note. As said before it seems as if the thicker walls killed the rasp. Also no codes with our set up.
They're installed on my buddies car and its pretty much stock with an intake. Before it felt like a nice pull, but driving the car after with the hollowed pipes was a difference. Enough upgraded pull to feel a difference. Im not talking WHOA thrown back into seat but the force on take off was defiantly harder than before.
They're installed on my buddies car and its pretty much stock with an intake. Before it felt like a nice pull, but driving the car after with the hollowed pipes was a difference. Enough upgraded pull to feel a difference. Im not talking WHOA thrown back into seat but the force on take off was defiantly harder than before.
#16
Do you have a pics of the O2 defoulers that you are using? specifically the size of the hole.
Are you banging the cores out with a hammer or cutting the cats apart and pressing out the cores?
Are you banging the cores out with a hammer or cutting the cats apart and pressing out the cores?
#17
Racer
iTrader: (1)
This has been an ongoing thing for YEARS. Gutting cats is not new at all. I would be interested but 200 bucks is pretty steep just to gut a cat. I would think 200 if I DON'T send you my cats is a good price since if I were to purchase new PCD's I get to keep my stock parts to re-install if I sell the car or don't pass emissions for some reason.
Also I would only be willing to spend that money if I could see before and after dyno sheets as it has been proven time and time again that there is very minimal gains by gutting your cat.
I very highly doubt you are getting anywhere close to 8hp gains with this but if you are my interest would be hightened. Dyno comparisons have been done with numerous cars gutting cats and usually only get 1-2 hp gains max.
Also I would only be willing to spend that money if I could see before and after dyno sheets as it has been proven time and time again that there is very minimal gains by gutting your cat.
I very highly doubt you are getting anywhere close to 8hp gains with this but if you are my interest would be hightened. Dyno comparisons have been done with numerous cars gutting cats and usually only get 1-2 hp gains max.
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Italiano (01-18-2013)
#18
Drifting
Not to high jack...But not sure if that is safe for the car...Hollowed out pre-cats vs Deletes are alittle different...Heard about the danger of precat subtrates falling out being dangerous..Maybe someone can chime in and explain this better...
#20
06 Anthracite TL
As long as the precat matrix is destroyed and the hollowed out header is cleaned out, typically with water and compressed air, it should be no problem. The precat matrix is typically very friable, so it breaks up /disintegrates easily and should be easy to remove completely.
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Italiano (01-18-2013)
#23
Suzuka Master
iTrader: (2)
That's a very interesting idea. I have a Toyota MR-2 and when those cars were built, the precats had a nasty way of breaking down prematurely and trashing the engine. The owners of these cars either replaced the OEM precats with a header (like I did) or took out the factory header with the precats, essentially destroyed them, cleaned out the head completely to get rid of any residue, and reinstalled the header. As a result, no further engine failures. The main cat is still in the car, intact.
The cars with precat deletes will still pass emissions (as mine has) since my header is encased in the OEM heat shields, and in NJ, it's basically an OBDII code check and driving over a camera to make sure the main cat is still there. Since the precats only help with emissions during the warm up of the engine, they really don't do a whole lot otherwise, and in this case, the decatted header will look OEM, so the emissions check should present no issue. Overall, it sounds like a good idea.
The cars with precat deletes will still pass emissions (as mine has) since my header is encased in the OEM heat shields, and in NJ, it's basically an OBDII code check and driving over a camera to make sure the main cat is still there. Since the precats only help with emissions during the warm up of the engine, they really don't do a whole lot otherwise, and in this case, the decatted header will look OEM, so the emissions check should present no issue. Overall, it sounds like a good idea.
#25
BANNED
iTrader: (33)
^how are HFPC's safer than a hollowed out OEM cat? it's essentially the same thing.
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Italiano (01-18-2013)
#28
Suzuka Master
iTrader: (2)
As far as the price, I don't see the value at $200, unless "looking" OEM is important. $200 is pretty crazy money to bust the substrate out of two cats.
What are PCD's going for, like $350? Then you can flip your stockers for over $200 to someone who has cats that failed and you're down $100-150 with proven PCD's. I'm sure these will make some power, but not what the PCD's will. Velocity of the exhaust coming out of the heads will be impeded compared to PCD's. you've got the smaller openings and then all that increased pipe volume that's going to slow down flow.
#30
06 Anthracite TL
Actually the precats are not the main source of emission reduction- that job remains with the main catalytic converter. The precats reduce emissions when the engine is warming up, and after its warm, they do nothing. That's when the main cat is most effective, and with the main cat still intact, it will still pass emissions (as long as the car is warmed up and if it's going to have a 'sniffer' test- mine has passed this way before NJ went to just an OBDII check and check to make sure the main cat is present. If it's just an OBDII check and main cat presence check as in NJ, the precat delete won't be noticed. As I have said, I have personal experience with my other car (the MR-2) and it has the same setup (O2 sensors in bungs on the precat header). With the precat matrix gone, there's no OBDII codes and the main cat is still present, doing its job. My car has been like this for about 6 years, and it's passed NJ emissions consistently. Unless they take off my heat shields on the car, it will never be noticed by anyone (and the heat shield removal is a bit of a job in itself on the MR-2).
There's a lot of MR-2 owners in California that have done the precat delete and the car still passes emissions testing. The setup in the MR-2 is just like any other car made currently. Granted, by taking out the precats, what you're in essence doing is bringing the car from ULEV status to LEV status. If you remove all of the cats, then it won't pass emissions.
I know the MR-2 is not an Acura TL, but the setup is the same.
There's a lot of MR-2 owners in California that have done the precat delete and the car still passes emissions testing. The setup in the MR-2 is just like any other car made currently. Granted, by taking out the precats, what you're in essence doing is bringing the car from ULEV status to LEV status. If you remove all of the cats, then it won't pass emissions.
I know the MR-2 is not an Acura TL, but the setup is the same.
Last edited by erdoc48; 01-18-2013 at 11:58 AM.
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weaselbob74 (01-18-2013)
#32
I agree that one isn't any "safer" than the other, but they're hardly the same thing. One is hollow, one contains a low count substrate.
As far as the price, I don't see the value at $200, unless "looking" OEM is important. $200 is pretty crazy money to bust the substrate out of two cats.
What are PCD's going for, like $350? Then you can flip your stockers for over $200 to someone who has cats that failed and you're down $100-150 with proven PCD's. I'm sure these will make some power, but not what the PCD's will. Velocity of the exhaust coming out of the heads will be impeded compared to PCD's. you've got the smaller openings and then all that increased pipe volume that's going to slow down flow.
As far as the price, I don't see the value at $200, unless "looking" OEM is important. $200 is pretty crazy money to bust the substrate out of two cats.
What are PCD's going for, like $350? Then you can flip your stockers for over $200 to someone who has cats that failed and you're down $100-150 with proven PCD's. I'm sure these will make some power, but not what the PCD's will. Velocity of the exhaust coming out of the heads will be impeded compared to PCD's. you've got the smaller openings and then all that increased pipe volume that's going to slow down flow.
These cats are ceramic, worth nothing In scrap. You may get $50-100 and sit on them for months as type s ones are a bit more free flowing and desirable and go for $150 ish. Also IMO I wouldn't spend anything on used being that it takes almost 4 hours to install with the risk of not knowing if they failed. Same with things like app sensors/alternators etc. it's always better to go new. If your just trying to fix the car and sell it working, you may find a buyer.
I was thinking it would be a lot harder but I would be at $120 plus shipping. It does take a while and I am also including the defoulers. Again no codes and yes it's not ass efficient but you cant tell me it's 1-2 hp. These cars are very restrictive so gaIns will be there..
Precats have rasp and won't pass emissions. These are oem look, no rasp and gains are there from my install last night on my buddy's car.
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justnspace (01-18-2013)
#39