Mod Thoughts

[imagine]

Hi - '14 TA w/ 8500 miles here. Car has a drop-in K&N and the Arrow PCM. Wondering the practical gains/feedback on going with an UD pulley and also deleting 2 out of the 4 cats. Not really interested in going the full headers/exhaust route. Already like the sound, more interested in the performance per buck. Thanks!

- Matt

[7TH_SIGN]

Removing all four cats will net you power gains that you can feel. I did it on all my Vipers. Not only is there a power gain but the tempature inside the cabin drops tremendously.

[Topplayer]

^ does it drone more or less on the highway?

[Stealth78]

UD pulley and high flow cats will get you about 15-20whp

[Dman]

Best advice is to call Andy, JonB or Mark. They've seen every combo and dyno and can walk you thru mods with more fact than opinion.

After 18 yrs and several modded vipers, and seeing dynos, going to 2 cats from 4 will be 2-7hp. Most will tell you it's a mod to reduce sill heat, not power. UD is documented well on the forum, call it 10rwhp on avg. Headers with hi flow cats with stock cat back doesn't make her much louder but frees up good HP for the $, dynos with the Arrow you already have show an extra 20-30rwhp, there's documented variance for sure. But a total of 40-50rwhp is typical with headers/hiflows and Arrow.

But again, call someone who's done hundreds of vipers and get their direct input, and listen, it'll save time and money. All us forum jockeys have all kinds of opinions for other peoples cars, lol.

[7TH_SIGN]

^ does it drone more or less on the highway?

I had the AP exhaust on mine. Catless. Absolutley zero drone and no echaust cabin odor.

[Special Ed]

I have JonB's hi flow cats and belanger muffler set up, underdrive pulley and arrow pcm. No drone, nice tone, greatly reduced side sill heat and nothing but smiles in the power department.

[ViperPete]

I picked up 75+whp from headers and tune.

Stock exhaust is really heavy. Belanger exhaust has reduced in cabin temps tremendously. Side sills only get warm. Never hot.

[imagine]

Thanks for all the feedback and replies! Luckily for me, Doug Levin is a good friend and lives 15 minutes away. Decided to just remove (2) of the cats for now and see how it sounds/performs/cools. I've just been making minor iterative mods to the car. Started w/ Arrow PCM, then drop-in K&N, and now the (2) cat delete.

[BlknBlu]

you will get debateable answers on the Air filter. In 2008 they reworked the filter to get maximum flow over the drop ins. some lost HP, others claim gains. I tend to believe what the Engineers said.

Bruce

[Vipes]

What about high flow cats? Would the power gain be about halfway from stock vs no cats?