size of stock catalytic converters?

[Indy]

Hey guys. Anyone have the measurements for the stock cats on a gen2 (99). I want to cut the stock ones out and weld in some high flow converters. Are the diameters on both sides 2.5"? What is the length of the cats? If someone has the stock cats laying around, could you take the measurements? I don't want to take the side sills off until I start on the project.
Here's a pic with the measurements that I would need.

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Thanks. I want to reduce the heat a bit, as well as gain some performance and sound. How much louder will high flow cats be compared to the stock ones?
cheers

 

[Fatboy 18]

Ive got some in the Garage, Give me an hour or so and I will get back to you with the measurements

 

[Indy]

Great! Really appreciate it! I want to make sure I order the right size, and get most of the cutting and welding done before taking the stock ones off.

 

[vancouver-gts]

Indy, the in/out dia is 2.5" . I'll do the same to my 99 this spring after taking the car through aircare. Had my sills off to repack with extra insulation in the past . The cats looked like at least 17-19" long. I'll be going with MAgnaflow cats. Have Magnaflow mufflers you could see through in the back already.
Ps; the 99 will be eligible for collector status by 2014 because of the low production number for the year [ set to 1500 per ICBC here in BC] so I might even go catless altogether after that since the car won't need aircare then. Unfortunately, our V-10's will never sound this good as my buddy's Ultima GTR with the LS V-8engine, following the Carrera GT http://www.youtube.com/watch?v=wqtwKURzZOc

 

[Indy]

cool. I took mine through aircare in the fall, so I'm good to go I've got straight pipes in place of the rear muffler, but it's still a bit quiet. Are you also getting rid of the side resonators, or leaving those in place?

Is your buddy selling his GTR? There is one for sale here in Vancouver, and I'm guessing there aren't that many around...

 

[vancouver-gts]

Is your buddy selling his GTR? There is one for sale here in Vancouver, and I'm guessing there aren't that many around...

yeah, he's selling the GTR, asking 89K. I would buy it in a heartbeat if had the extra cash! He lives in Whiterock, we'll cruise together next year if he still got it. There was only one more GTR [ red one with 383 Chevy] here in Vancouver that my friend sold years ago, landed in Calgary.
My other buddies from Whiterock have a 07 Noble M400 , 1999 Ferrari Maranello 550. My 99 GTS , all silver cars cruising all over the greater Vancouver area.
If you see us on the road join in.
You see the silver Noble with the black Ultima here http://www.youtube.com/watch?v=BLbtnPO9Vzs

 

[Fatboy 18]

OK, from the start of the cone to the end of the cone at the opposite end of the cat is 20 inches. Diameter of the pipe is 2 and half inches

Hope that helps

 

[Indy]

thanks a bunch!!!!
Time to start another project.

 

[Indy]

One more question. Are there no front oxygen sensors on the Viper? Looked under the Viper today, and couldn't see any, unless they're hidden behind the side sill.

 

[Indy]

Just ordered a pair of Magnaflow High Flow converters (#59956 with metallic substrate and 200 cpsi). They seem like the best deal out there. All the cheaper ones are either ceramic substrate or higher cell count. Anyways, I'll post some pics when I'm all done. thanks again for your help, guys! cheers

 

[vancouver-gts]

There are two sensors ,one each side, before the cats. Two more after the resonators.

 

[Fatboy 18]

O2 sensors are on the stock headers about a third of the way down the pipe by the engine block, oh and happy new year

 

[Indy]

ok, great. I didn't even check the headers.
Any hp/torque gains with high flow cats...just curious.

 

[Fatboy 18]

Yes Not sure how much but you do gain

 

[Indy]

Update:
Also ordered some 12" bullet mufflers to replace the stock resonators. Might as well do everything at the same time. Already did the rear muffler delete last year. I'll post some sound clips when I'm done, and I'll try to measure the decibel difference between the current setup and the new one. Happy New Year everyone

 

[Indy]

Had a bit of time to put my exhaust together Turned out quite nice. Magnaflow high flow cats up front, and some small glass packs to replace the stock resonators, just to mellow out the noise a tiny bit. Rear has the muffler delete with straight pipes. Everything fits together nicely, and it sounds great. You can really hear the hot 708 cam at idle now. Very brutal sound under acceleration, but not bad when cruising (you can still have a conversation and listen to a CD). So I'm quite happy. Neighbours probably wont be too impressed with the noise, but most of them are also car guys, so it's all good
Here are some pics:

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Stock vs new

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cheers

 

[Dom426h]

Nice PICS.

Everyone with stock headers should be running a system similar to this IMO.

 

[mgeorge]

Looks great, looking forward to the sound clip when you have a chance.

 

[Indy]

I'll try to get a video clip posted when the weather turns nicer, maybe early Spring. I'll post that on the exhaust thread. Exhaust note definitely scares old people

 

[Fatboy 18]

Looks good, what paint did you use to paint the exhaust system?

 

[Indy]

The paint is high temp aluminum (or "aluminium", as you say in Britain ) in a spray can. I've used it before, and it's very sturdy. Doesn't burn off like some others I've used.

 

[Fatboy 18]

Thanks

 

[GTSHolgi]

I see that you are using clamps to connect the cats to the (stock?) headers. From what I have read so far, this is rather unusual as most people weld the cats to the header pipe. Any issues doing it this way (stability, leakage...)? How much of the header pipe is reaching into the cat? I am planning to install HF cats too...

Great write-up, BTW.

Thanks!

Holger

 

[Indy]

Well, on the stock system, it had a clamp connecting the cat to the resonator.
I was considering welding the magnaflows on the header pipe, but then I figured I'll just weld everything together on one piece, and use a clamp up front. Doesn't really matter where the clamp is, as long as it seals well. Mine goes in quite a bit, I would say around 3 inches. It's really tight and doesn't move or wobble at all.

 

[GTSHolgi]

Just ordered a pair of Magnaflow High Flow converters (#59956 with metallic substrate and 200 cpsi).

I have seen on the Magnaflow website, that this cat is listed under "pre-ODB II" models. Now that you are having an ODB II Viper I am wondering if you have any CEL or codes thrown by these cats?

Holger

 

[Indy]

No codes....I still have the O2 sensors in place and no problems whatsoever. Are you planning on going the same route as my setup? Just so you know, the exhaust has a very brutal sound to it and certainly is a LOT louder than before - with German laws, you might get some problems just because of the high dB volume....

 

[GTSHolgi]

I am going to install Corsa Catback w/ HF cats. I assume (and hope ) that my setup will not be as loud as yours, where you have removed all mufflers. Just want it a bit louder and more refined compared to stock.

BTW: After I have driven the car 4 times again since March 1st we are no back to winter mode (-8°C and snow -> absolut DISLIKE!!!)

Holger

 

[Indy]

I heard about the snow in Europe....that *****, but in March I'm sure that by the weekend you'll be enjoying the Viper under the sun again We're pretty lucky with snow here in Vancouver....for the past 3 years there was virtually nothing.

 

[vancouver-gts]

Indy, had my car out last weekend. Saturday was great, Sunday not so much. I'd like to hear what your car sounds in person. When I heard you passing by Petras you went by quickly. Had my car aircared Saturday morning, passed with flying colours. They were looking for the cats with their mirror [ young girl first] and I kept telling her that she won't be able to see it unless I dismantle the sill. She called her supervisor over [ an older hag] and she looked with her mirror, kept saying, I can see it, I can see it. Didn't want to argue with her, I smiled and let her go

 

[Indy]

When I did Aircare last year, the guy there asked about the cats as well, but when I told him they're under the sill he took my word for it. I guess this can be a problem for some more picky inspectors - I'm glad that AirCare will be discontinued by the end of 2014. What a money grabber for nothing. There are so few old cars left nowadays in Vancouver, it just doesn't make sense anymore.