Catalytic converters removed?

[Terry Holtz]

Hello... I would like to hear from C-5 owners their experiances in removing their cats. Weight savings? HP gains? Did it pop codes?

Anyone?

 

[Ken Anderson]

BAD IDEA for a street car!

 

[TODD L GRIFFITH]

The cats removed will definitely throw a code. The need for 02 simulators would be needed to be installed. The expected hp gain would be approx. 5hp. Not really worth doing. In addition, the vehicle may fail the next emissions inspection. You are better off installing high flow cats.

 

[Terry Holtz]

>>>>>>The cats removed will definitely throw a code. The need for 02 simulators would be needed to be installed.<<<<<

Would the o2 simulators stop the code from coming up? Thanks for your reply

 

[TODD L GRIFFITH]

Yes, the O2 simulators would trick the PCM into thinking that the cats were still installed by producing a .450mv signal back to the computer. The simulators are to go in place of the rear O2 sensors behind the cats. The simulators can be purchased through Mid America for about $150.00. The link to the online catalog is www.madirect.com .

 

[c4c5specialist]

HI there,
The BAD side to simulators, is that this will throw off your fuel trim calculations.
Do NOT expect that there will NOT be issues with how your vehicle runs with the simulators in your car.
Just a word of caution, because not everyone wants to LS1 edit for a couple hours to forge calibrations.
Allthebest, c4c5

 

[TODD L GRIFFITH]

Good point c4c5. I would not recommend removing the cats completely. Additional tuning will be needed. LS1 edit or a hand held programmer with good capability like the $420.00 Pedator is not too cheap on top of simulators just looking for a few ponies. I'm not sure if Terry has done this already or not. Have you already removed them, or just thinking about it?

 

[Terry Holtz]

I have not done it. Just thinking about it. I have heard the cons, but was hoping to hear some good news from the other side. If they never post, as it looks like, then I suppose I will blow the bank on stainless long tubes, hi-flow cats, and titanium rear exhaust. Any recomendations? Realistically, how much torque and HP gain should I expect? weight savings?

Are hi-flow cats really hi-flow? Why didn't Chevy put them on in the first place, at least for the zo6's?

Perhaps the people who sell the O2 simulators should give notice of the fuel trim calculations problem. They never seem to mention the problem in their ads.

Thanks, Todd and C4C5.

 

[Remo]

Advise From an Old Guy

Terry,

Put some hi-flow cats on it, a Corsa X-Pipe, a Borla Stinger exhaust system and call it a day. The exhaust will flow smoother, you'll get a few more ponies and the car will sound sweet.

Remo:cool

 

[c4c5specialist]

HI there,
Personally, from a technical point of view, every aftermarket cat system I have seen may throw a code at one time or another.
I have found, so far that Kooks headers and converters system have been the best overall as far as power, emissions worthiness and quality.
It takes me about 6 hours to install, but worth it in my opinion.
Allthebest, c4c5

 

[KANE]

I agree with C4C5. If you are looking for more power- run high flow cats and low back-pressure exhaust. You need some back pressure. Use the cats to get it. They will help optimize the air/fuel ratio and ensure you have the most power for your vette.

 

[Terry Holtz]

>>>>>>Kooks headers and converters system have been the best overall as far as power, emissions worthiness and quality.<<<<<

Are Kooks long tube headers stainless? And after the high flow cats, I'd like to go titanium, so that if nothing else, I've made my car a little lighter! By the end of February, I will either get hi-dollar brakes... or an exhaust system.

 

[Terry Holtz]

>>>>>>>Put some hi-flow cats on it, a Corsa X-Pipe, a Borla Stinger exhaust system and call it a day.<<<<<

Remo, you don't think long tube headers make much difference?

 

[TODD L GRIFFITH]

You could possibly see 25hp extra from long tube according to my ls1/ls6 performance engine build manual based on a ls1 with long tube headers, high flow cats and a performance intake. Not too bad of a gain. The removal of the cats is not worth the small gain you would receive +/-5hp. After buying O2 simulators and reprogramming, you would have atleast half the money spent towards a long tube header system anyway. I like the deal with the Supermaxx system. $1499.00 for long tube headers, high flow cats and x-pipe. On my old 99 hardtop, I spent around $2000.00 before this supermaxx system was available. http://www.rpmoutlet.com/c5hits.htm this link has a nice deal too for $1295.00. I didn't really read it to see if the high flow cats were included, but the $1499.00 system has it all from http://www.madvet.com/shop?part=1.5778.618543 I'm thinking about the supermaxx system for my ZO6 at those prices.

 

[c4c5specialist]

>>>>>>Kooks headers and converters system have been the best overall as far as power, emissions worthiness and quality.<<<<<

Are Kooks long tube headers stainless? And after the high flow cats, I'd like to go titanium, so that if nothing else, I've made my car a little lighter! By the end of February, I will either get hi-dollar brakes... or an exhaust system.

HI there,
Yes, the complete system is stainless, headers, connection pipe, cats, and x pipe.
Light, could be, but I have not weighed them.
Allthebest, c4c5

 

[Remo]

>>>>>>>Put some hi-flow cats on it, a Corsa X-Pipe, a Borla Stinger exhaust system and call it a day.<<<<<

Remo, you don't think long tube headers make much difference?

Terry,

I'm just suggesting a cost effective way to get a smooth flowing exhaust system. In fact you could even skip the hi-flow cats and avoid the potential 02 code issue. Terry, I've been spending money on fast cars and performance parts for many years and here's something I've learned. No matter how much you spend there's always someone out there that has something faster (or so they say). But in the end, most of these characters never actually drive the cars anywhere near the limits of the performance envelope. So keep things in perpective and do what you think makes sense.

Remo:cool

 

[Terry Holtz]

My 98 has 60,000 miles. Do catalytic converters slowly become blocked?

 

[TODD L GRIFFITH]

Yes Terry, over time they will become less efficient. It also depends on how good your air/fuel mixture has been. If the car runs really rich, they will not last as long. There are alot of factors acting on how long your converters will last. According to GM, you should replace your O2 sensors every 30,000 miles. This will aid in keeping a good accurate voltage reading back to your cars computer to adjust the more correct amount of fuel the engine is receiving, and prolong the life of your converters. Also, you may note a build up of soot around the tailpipe, and a strong sulfur smell during idle. This may be an indicator of running rich. The best and most accurate way to check how fuel rich your engine is running, is to buy a diagnostic tool that will display your short and long term fuel trims. Negative trims are rich, positive trims are lean. Most engines run slightly rich anyway, unless you have replaced the MAF with an aftermarket higher flowing sensor, or have installed a performence intake that could lean your mixture a bit, due to unmetered air coming in through the MAF that the computer can't read to adjust the proper amount of fuel. That is much worst, running lean. Slightly rich is fine. An air/fuel mixture of 14.7:1 is perfect, in a perfect world, but damn near impossible to achieve. Like I said, most cars run slightly rich 12.5:1 - 13.5:1 air/fuel ratio. When you mentioned the manufacturers of the O2 simulators, and, "they must know about........." the need for tuning, well they do. The O2 sims. put out a voltage of .450mv. That is no mistake, because that is the O2 voltage readings @ a perfect 14.7:1 air/fuel mixture. There is a reason for everything........... Good luck with some LT headers and high flow cats. Replace all (4) O2's if you get the new high flow exhaust system while you are at it.

 

[USRobo]

Removing Cats

What if he only gutted the Pup Cats? Would that provide any additional HP or throw a code?

I believe the Z06 exhaust do not have Pup Cats and they perform better.

The cats removed will definitely throw a code. The need for 02 simulators would be needed to be installed. The expected hp gain would be approx. 5hp. Not really worth doing. In addition, the vehicle may fail the next emissions inspection. You are better off installing high flow cats.

 

[DanHammer]

Hi there ... my suggestion ... leave the cats to save you the headaches. Now if you are after increasing HP ... then you need to upgrade your stock exhaust system and intake system as well, to balance it out. Think of the engine as an air pump ... the more air you can suck in and out fast, is HP.

My entire exhaust system is customized and also is stainless steel ... from the headers (TPIS coated LT) high flow cats, to H pipe, to a center muffler (Borla) and (BB) Billy Boat Bullet exhaust system for the rear with quad 4" inch round tips. I had to dump the X pipe ... actual results on dyno was less. H pipe delivered a more balanced and improved HP in power band range than the X pipe on my engine setup. This setup on my 2001 has passed state emmissions and haven't have any codes thrown at me. My intake setup ... a secret

Later .... Dan