Boosted GT and Fried Cats

[DougS550]

To all of you boosted drivers.

I have a 20 GT vert with a G2 ESS on 93.
I'd like to upgrade or eliminate my cats. Given I enjoy the sound my car has now wondering what you all suggest? I have a Steeda H pipe and Active Exhaust.
I've heard others say eliminating the cats all together doesn't sound good.
Considering performance cats.
I don't have LT headers nor am I convinced I need them as I'm happy with the performance now.
The car is my summer cruiser and I don't track it.
For me and knowing Non Boosted Stock cars from factory Cats, were not designed for Boosted applications like the GT500, Hellcat ETC. I would highly recommend you remove them or install ones made for Boosted applications. You engine can and or will be destroyed if and or when your Stock GT Cats clog. To replace an engine is quite costly?. Good Luck
Thanks everyone!

Sponsored

 

[engineermike]

Mike. Are you making custom tunes for FI owners?

Sorta, depends on the scope and time commitment.

 

[ZXMustang]

Sorta, depends on the scope and time commitment.

I’d like to pick your brain some time. I’ve been tuning my own whipple car for some time now. Been lots of fun and very interesting.

 

[pmor4243]

To all of you boosted drivers.

I have a 20 GT vert with a G2 ESS on 93.
I'd like to upgrade or eliminate my cats. Given I enjoy the sound my car has now wondering what you all suggest? I have a Steeda H pipe and Active Exhaust.
I've heard others say eliminating the cats all together doesn't sound good.
Considering performance cats.
I don't have LT headers nor am I convinced I need them as I'm happy with the performance now.
The car is my summer cruiser and I don't track it.

Thanks everyone!

You might want to check out the thread I started a few weeks back this. My cats went out after about 10k miles. Went with deletes and bought another set of factory manifolds and welded a flange to the cats for easy removal/install.

Catless was too loud for me so I added additional resonators to the factory system and that was a very effective solution. To the noise. Brought it very close to how the factory system sounded, but with not cats.

still deciding on what I am going to do long term regarding cats vs no cats, but this gives me a solution I can work with.

 

[Frank]

I have the 2M'"s and 14 back exhaust manifolds. I had to cut the flange on the drivers side pipe reclock the flange and weld. I have active exhaust and the stock resonator and I hate my car. Its to loud for me and drones in the two thousand rpm range. My cats went at around twenty thousand miles.

 

[Andy13186]

Once you delete cats you need an aftermarket valved exhaust IMO for cold starts to be reasonable. Varex valved is good for this. Insanely loud at WOT when the valves are open but no drone, and quiet with no drone when cruising.

Dont keep the valves closed when doing pulls though, way too much backpressure. literally went from 5's 60-130 with them open, to 8's with them closed.

 

[CUL8R]

You could do the 2M fabrication cat delete pipes, and then cut in some 3" universal cats (Gesi 300 or 400 cell) with slip or butt joints. That way you would still have your OEM manifolds, and could easily remove/inspect your cats. You do have to cut the drivers side cat off, and weld the flange onto the pipe though.

If your active exhaust is OEM, you can have your tuner change the position of the flaps for each drive mode, to suite your taste. Like many others, once I installed Long tubes, my exhaust was too loud for my old ass (even with the OEM resonator and OEM active cat back). I was considering adding resonators, but then decided to have Wengerd adjust the valve positions. Quiet is still closed, normal is 25%, Sport is 40%, Track is wide open. All settings go to full open when WOT.

Decided your suggestion is the route I'm going to go. Keep the stock mani's, and I purchased the GESI Gen 2 Advanced G Sport HO cats. I'll discuss the 2M with my exhaust guy to see what he thinks is easiest.

Thanks all!
John

 

[stannypack]

You might want to check out the thread I started a few weeks back this. My cats went out after about 10k miles. Went with deletes and bought another set of factory manifolds and welded a flange to the cats for easy removal/install.

Catless was too loud for me so I added additional resonators to the factory system and that was a very effective solution. To the noise. Brought it very close to how the factory system sounded, but with not cats.

still deciding on what I am going to do long term regarding cats vs no cats, but this gives me a solution I can work with.

Which resonators did you go with? I ordered a pair of Vibrant 1794s.

 

[pmor4243]

Which resonators did you go with? I ordered a pair of Vibrant 1794s.

I went with these (Vibrant 1141) as I had good luck with them in other applications: https://a.co/d/2SqeMQd

They tucked in nicely just before the mufflers

 

[stannypack]

I went with these (Vibrant 1141) as I had good luck with them in other applications: https://a.co/d/2SqeMQd

They tucked in nicely just before the mufflers

Did you go with the 2M cat delete kit?

 

[pmor4243]

Did you go with the 2M cat delete kit?

I did. They are pretty cocky on their site about fitment and don’t expect any help from their support (they wouldn’t even bother to help me out with ordering a couple of extra flanges).

But if you can weld or are having a shop do it they should go in fine. Mine absolutely did not match up the factory pipes post deletes without some pretty serious modification to the ends. Not a huge deal as you have to weld anyways but it wasn’t a plug and play set up.

 

[stannypack]

I did. They are pretty cocky on their site about fitment and don’t expect any help from their support (they wouldn’t even bother to help me out with ordering a couple of extra flanges).

But if you can weld or are having a shop do it they should go in fine. Mine absolutely did not match up the factory pipes post deletes without some pretty serious modification to the ends. Not a huge deal as you have to weld anyways but it wasn’t a plug and play set up.

I had a question, I only see 1 flange in my kit, but wouldn't you need 2 since 1 should be welded onto the cut off header side and 1 welded onto the cut off cat?

And yep I'm having my shop do everything luckily.

 

[pmor4243]

I had a question, I only see 1 flange in my kit, but wouldn't you need 2 since 1 should be welded onto the cut off header side and 1 welded onto the cut off cat?

Going off of memory, the passenger side bolts up to the existing flange and already has a flange on the 2m pipe. The driver side 2m pipe already has a flange on it as well. You have to cut in front of the cat and weld the other flange to the factory manifold.

So you should only need to weld one flange to connect them to the headers.

I wanted an additional set to weld to my factory cats so I could swap them in and out but ended up just cutting one off a factory manifold I picked up for cheap.

 

[stannypack]

Going off of memory, the passenger side bolts up to the existing flange and already has a flange on the 2m pipe. The driver side 2m pipe already has a flange on it as well. You have to cut in front of the cat and weld the other flange to the factory manifold.

So you should only need to weld one flange to connect them to the headers.

I wanted an additional set to weld to my factory cats so I could swap them in and out but ended up just cutting one off a factory manifold I picked up for cheap.

Ah so I do need another flange for the cat since I'll need to swap them on and off for emissions... you said 2M doesn't sell just the flanges? I got my kit off facebook marketplace.

Oof I just read their FAQs lol.

 

[pmor4243]

Ah so I do need another flange for the cat since I'll need to swap them on and off for emissions... you said 2M doesn't sell just the flanges? I got my kit off facebook marketplace.

Oof I just read their FAQs lol.

Correct, if you want to swap them you’ll need one for you factory driver side cat.

I asked them if I could buy one for specifically that and they told me they don’t sell the flanges. You might have better luck.

Sponsored