Hi flow cats and Supercharger question

[King RT10]

My high flow cats seem to get really hot with the supercharger
installed . Has anyone else noticed this. I am not talking hot to the touch but instead making diamonds hot.
Could they be restricting the exhaust flow causing heat. People come up and say "Hey nice car,then as they get closer *** my sunglasses just melted to my face" Sure its kinda funny but I would rather have more power.
S/C plus stock header with high flow cats = Sun

 

[GTS-R 001]

King RT,

I have the same problem, B&B high flow cats, burned right up but no problem b4 supercharger. I am going to cut them out and go catless with O2 sims.

 

[Neil - UK]

So would stock headers,cats and catback work ??

 

[Joseph Dell]

I use the Random Technology hi-flow cats and have no issues with heat. In fact, the side sills are cooler w/ the Random Technology hi-flow cats than they were with the stock cats.

I wish I had some insight!

JD

 

[1TONY1]

There are a few that have had this problem.....to the point of the paint burning off and melting parts. Be careful. The problem is the a/f mixture, the cat does not like it at all. I think it is mostly a problem at idle and not while moving...not due as much to air flow but due to a different mixture. This is based on my sills getting hot enough to blacken the paint at idle then the temp after a drive not being bad at all. The mixture idle comes from Sean talking with his cat manufacturer and the guys that did the a/f..dyno testing on his car. My cats were the stock cats shortened (cut in half) which seems to be a common thing.
My fix was to replace the cats with straight 3" pipe....very cool side sill and VERY LOUD exhaust. I have nothing against loud cars...I have two more that are a whole lot louder but I don't drive them often or very far. My fix for the loudness was to add "another muffler" in front of the **** that was already in the rear of the side sill. So now I have the race **** (in the pic below) where the cat was and behind that I already had a dynomax ultraflow race ****. There is another thread where I had my problem and I got a few negative responses on this Moroso ****. I took db reading with the straight pipe and then with the extra muffs on and there is substantial difference in db and to my ears.....most of the drone of the straight pipes is also gone. The four muffs compared to the cats and two muffs to my hearing is very close....I think it may still be a touch louder. As far as flow I will have to base that on the theory that sound = flow and if it is as loud then it flows as well. While this is not always true its all I have to go on for lack of dynoing or racing EVERY change. I can say that SW went 1.56 60" and a 6.85 1/8 mile at voi and I went a 1.59 60' and 6.88 1/8 mile with this exhaust. SW had rockers and I do not. Don't no the exact exhaust set up he has but I would guess high flow or no cats so in comparison that's not to bad. I am going to do a flow bench comparison of my modded cat and a moroso muffler...it will not show the numerical flows like a head flow bench but will give a flow in " that can be used for comparison. I will probably test a few more muffs and a few cats if I can, just to give a better concept of the difference in flow. If you have stock exhaust then a cat delete may be fine. Remember: DO NOT sit and idle for more than a minute unless you are closely monitoring the sills.

 

[RedGTS]

Hey Tony, I got some straight 3" stainless to replace my hi-flow cats, but someone told me that stainless needs to be TIG welded (all the muffler shops around here use MIG welders). How did you do yours, and do you know if it really makes a difference how it's welded?

 

[fast?]

hey red,take that pipe to a muffler shop or machine shop and tell them to expand the pipe diameter at both ends(assuming you have a 3" set up) then you can slip them in and out when needed. get 4 exhaust clamps and clamp the ends.

 

[RedGTS]

Tony, I've got a full B&B system with the high flow "half" cats they use and their muffler (shiny thing for something you have to cover up). I just figured it would be easier to weld the straight piece in than try to flare everything and get clamps, etc., but now I don't know. The muffler shops around here won't remove cats, and the other guy I know who has a welder doesn't have a flare machine, so I would spend a while going back and forth if I go that route. Maybe I need to make a road trip to Chattanooga!

 

[cstegall]

Hey Ronnie..

Get down here to DFW...we'll find somebody to fix that red car so that it can keep up with the yellow ones

I am interested in this as well. I opened up my stock cats to 3's and then set my Belanger headers/exhaust on the car. DLM is now working on the car..so I may have the same problem as King.

Happy Holiday to all...

Clark

 

[1TONY1]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by RedGTS:
Tony, I've got a full B&B system with the high flow "half" cats they use and their muffler (shiny thing for something you have to cover up). I just figured it would be easier to weld the straight piece in than try to flare everything and get clamps, etc., but now I don't know. The muffler shops around here won't remove cats, and the other guy I know who has a welder doesn't have a flare machine, so I would spend a while going back and forth if I go that route. Maybe I need to make a road trip to Chattanooga!

<HR></BLOCKQUOTE>


You just need to let me install the s/c and do the exhaust at the same time. Even if you weld the pipes they need the flare to slip in or over....a butt weld isn't near as strong. Also you can buy a cheap exhaust pipe flaring tool that would probably do the job.

Also Neil-UK .... Stock stuff would be fine but you would need to keep check on the cats just like everybody else. Add headers and get more power with or without s/c but it will still
haul ****.

 

[RedGTS]

Hi Clark, good to hear from you! But I've got a strong hunch that DLM may have more to do with your car going fast than its color! My measley 600 rwhp likely won't measure up. Here's to a quick winter and a delivery from DLM to you in the spring.

 

[1TONY1]

Ronnie, I am pretty sure they can be done with a mig with regular steel wire. You could buy them a spool of stainless wire. I can fire the mig off and lay a bead on a piece of stainless to say 100%. I took the pains to get stainless bungs for my 02 sensors and tigged them in. I have a tig and a mig. Mine already had band type WIDE clamps on the front and rear, I also put some thin exhaust wrap under the clamps to prevent leaks. I got it at the local Advance auto parts. Your replacement pipe should be flared on the front and slip in the back..not flared in the back....what ever it slips in should be flared. I would give serious consideration to replacing the high flow cats unless I had a temp problem. What kind of exhaust do you have ? When I say mine was LOUD with the straight pipe I don't think folks realize just how loud I am talking but I am sure its different with different mufflers and rear mufflers could be different than them being in the side sills.
Also if you went to the expense of stainless tubing why weld them with regular steel wire or rod.....defeats the purpose.

 

[King RT10]

I thought just doing power runs made the hi flow cats hot but after idling around town the cats went nuclear and I started to smell something that was not viper freindly. Before the S/C everything was fine.
Now I have fission and creating my own black hole.

 

[SUN RA KAT]

I haven't had any weirdness with my Random Tech Ultra High Flow Cats (for over 525 HP) since I had my Roe Supercharger installed.
My side sills don't seem to get noticably hotter than before the supercharger.

Sean should be back & available for answering questions in just barely over one week.

 

[Doug Supercharged Vipers]

King RT10 -

If you feel your catalysts are experiencing elevated temperatures higher than normal you need to have the problem looked at.

Catalysts superheating higher than normal can become a fire hazard. Typically, I've seen this type of problem when the check engine light (SES) is illuminated due to a *malfunction of the O2 sensor*. The ECU adjusts the cylinder bank fuel trim with a positive correction value of the fuel metering, over-rich; holding the fuel injector pulse width open too long.

Hope this helps...