Random Tech makes some but there are very expensive. There used to be another company called Trubendz or something and they made some with Magna flow or Thunderbolt brand ones. I almost bought those a year ago but didn't and then they stopped making them. I have talked to some local shops and will be buying some of the before mentioned brands and having them welded into the mid pipe like where it would be on the LT location. Cut out the factory ones and put an open pipe in their place.
So now I am trying to decide between the trusted Magnaflow brand or Thunderbolt. They are cheaper and get good reviews online of people that have used them on all sorts of LS motors. Just thought I would help you in your search some. I have been looking into this project for awhile.

BDV

 

Good info. Thanks!!

 

I purchased the last set of highflow cats from trubenz. They made an exception after they pulled them from thier catalog. They work
great, give a little more sound and a little more horse. They fit perfect with a Magnaflow x pipe cat back system.

 

Did they say why they stopped making these ?

 

I have the Corsa exhaust on my car and was thinking about the Kooks headers but not sure if I want my car to sound that loud.

Trust me... Its not that loud. And you can get a high flow cat with most systems... kooks has that option as well. I got two high flow cats on my stainless works system (1&3/4 primaries, 3 inches all the way back). They mild it out just enough but its also real loud when you are WOT... Which I do basically everyday when I get on the freeway. That first time you hear the exhaust snapping and popping on a shift... Insta-boner.

 

They did not say why they discontinued them. Im guessing lack of sales.

 

The headers by themselves don't add that much to the exhaust sound. Removing the OEM cats adds the most sound.

 

Removing the OEM cats adds the most sound.

That is good to know. I was wondering which part was going to make the most change in it. I still wonder how loud it will get when I go with the high flows and take out the Corsa resonator and replace with an x-pipe? I don't mind some more volume than what I have got but it still is a DD family car for a few more years.

BDV

 

Based on the reports of others, either removing the resonator (OEM or Corsa) or replacing it with an x-pipe often brings popping through the exhaust on decel. I believe a tuner can mitigate some that effect.

 

Well as it turns out I already get some popping during shifting whether up or down so I guess we are good there. I thought about having them tune it out but as it turns out I don't mind it and sometimes kind of like it! Hehe

BDV

 

Here is some useful info (for Calif).

There are no replacement cats listed for V1's except factory.

If the smog nazie does a visual inspection and even though the CAT may have a CARB #, it has to be listed in the book as applicable to that car, even if the CAT is used on a car/truck with the same motor.

SUCKS.

The "POP on decel" can be turned off in tuning.

 

I just did SMOG at a STAR station. They didn't look twice at them and I passed. I don't think you will get hassled for these as they have the appearance of a OE type replacement.

 

Turn off the "pop on decel?" How boring!

 

Headers sound great bouncing off the wall at the drive-thru...

 

My dad has said the same thing in the past about old cars he used to ride in! hehe

I am still going back and forth whether or not I want to do the headers and if I find that special deal I can't say no to then I guess I will pull the trigger but I know I will do the high flows for sure. And if I decide later to put them on the the other work is already done and I just bolt them in.

BDV

 

http://performance-curve.com/25thunderboltmetalliccatalyticconverter415250.aspx

are these the correct thunderbolt cats for our cars? if so i may order a set today

 

yes those are them. I have been looking between those or the Magnaflow 59956. if you get the thunderbolts let me know what you think and I will do the same if you like them. Also let me know where you mount them.

BDV

 

ill probably mount them in thhe same location as where you would on long tubes, as i plan on purchasing long tubes in the near future. but the cats on these cars are so restrictive. that and im trying to figure out where the sewing machine sound is coming from, valve train looks fine based on visual and the sound is alot more similar to exhaust leak over anything. ill probably buy the 2.5" (3" are like half the price). and im running magnaflow mufflers (previous owner) and it looks like they also did an x-pipe as well. so this may be the sound i am after. ill keep you posted and possibly post a vid clip of the sound after installation.

 

That is the exact setup I have been wanting to do for a year. Money just keeps going in the wrong direction ever since the trans went out in my burban last summer. Have to do all the general stuff before the fun stuff! I would greatly appreciate your input and sound clips on everything.

BDV

 

I use to run gutted cats for a while (just the exterior shell ) for a temp solution and the went with bassani high flow cats x pipe and cat back on my mustang. Never had a problem with inspection. Honestly when I ran my car through inspection without cats they didn't check as there was no cel to give them a reason. Most places in Texas are pretty relaxed. Once I get more comfortable and people recognize the car I plan on running long tubes with of road x..... Though, and I may be flamed, I have yet seen a h pipe or an audio clip for an h pipe on the v...... Hmmmm.


Bigdaddyv- I'm assuming its an aftermarket x cause inspecting it it doesn't look OEM but the fact that the exhaust work is 2.5 OEM and the previous owner went with 2.25 and crappy Welds and tips I am unsure. The car is very deep at idle but I'm doing high flow cats trying to get away from the sewing machine sound I hear cause it bugs me that's what people hear prior to me passing. If I had the funds it'd be dropped out and 3" all the way back. I'll take before and after walk around idles and revving

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PS sorry for thread jacking

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How come? My hand held diablo worked fine on my 02 mustang

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I have a decent little shop here as far as the inspection goes. After I moved in last year needed it done and he was close. He dosen't seem to check closely on anything just as long as it is all good in the computer. Mine is up again in March and will probably go ahead and do it after I get inspected this year so I have time to play with it before it has to be done again as far as tune goes or anything. Just really want to know how the performance and sound goes.

BDV

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I run a tune through my Diablo. I got some datalogging done with it and got a custom mail tune. I know it isn't a dyno or chassis tune but she still screams and I can't keep traction for anything. Works great for me know until I get to cam and manifold changes.

BDV

 

Same boat as bdv... Minus inspection is due now

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It cost me over $1300.00 for parts and fab to get a pair of CARB cats welded onto some pipes I got from B&B.

The muffler shop guy was great and told me a whole lot of info.

Also, there was no guarantee the car would pass sniff.

I had the car tested and the #'s are in the mud, so I am happy as hell.

The CATS provided by B&B will pass in Arizona, but not Ca.

 

mine is going to run me no more than 400 total with cats and labor. Shopping around for best labor costs though after I decide to go magnaflow or thunderbolt. THunderbolts get great reviews online from use but not really knowing them or hearing much else hard to trust them over magnaflow. If there is someone else that is going to run them the same way I am thinking it will be a great review for me one way or another. If he is happy then I am sure I will be.

BDV

 

Wow, glad I picked up a set of bolt-in Magnaflow hi-flow cats from the classifieds for $125. At the time, I didn't know the alternatives were going to cost so much more just to replace the OEM cats.

 

Costs a little more due to custom placement and fit. I could get mine cheaper if I put in factory location but what is the fun in that? Plus moving the restriction further downstream will in theory create more power and efficiency.

BDV