[Solid_Sim]

I'm wondering if I would need to upgrade exhaust parts if I put the RotoFab cai and a pulley upgrade ?

Would be tuned on a dyno of course, but I wonder if the upgrade in air intake and boost would require more exhaust flow, cause I really love the stock exhaust sound and don't want to make more noise...

Also is changing the pulley a long install ?

Thanks guys

[Firehead640]

Originally Posted by Solid_Sim

I'm wondering if I would need to upgrade exhaust parts if I put the RotoFab cai and a pulley upgrade ?

Would be tuned on a dyno of course, but I wonder if the upgrade in air intake and boost would require more exhaust flow, cause I really love the stock exhaust sound and don't want to make more noise...

Also is changing the pulley a long install ?

Thanks guys

My research has told me that you don't need to upgrade exhaust, but stock is rather restrictive and an upgrade will result in better numbers.

Pulley install isn't supposed to take long, I watched a video and I think it took them an hour or something.

[Mcmillion]

Weapon X had a thread with what exhaust they recommend for what pulley size. I have a stock car with rotofab and will do an 2.3 upper and e85 blend next.

[SJFGTO]

Not essential, but if you are interested in adding HP, go with long tube headers. Just a cat back or axle back is more for sound. The stock exhaust is actually fairly efficient.

[Solid_Sim]

Originally Posted by SJFGTO

Not essential, but if you are interested in adding HP, go with long tube headers. Just a cat back or axle back is more for sound. The stock exhaust is actually fairly efficient.

Alright but going LT's will cleary make a much louder exhaust sound right? Wich I don't want...

What if I just change the stock cats for high flow cats?

Thanks for the answers btw guys, I might just do a small pulley upgrade to keep stock exhaust.

[Fraxum]

Originally Posted by Solid_Sim

Alright but going LT's will cleary make a much louder exhaust sound right? Wich I don't want...

What if I just change the stock cats for high flow cats?

Thanks for the answers btw guys, I might just do a small pulley upgrade to keep stock exhaust.

Are Hiflow stock cats available? I had LTs and NPP on my '16 SS and hated the raspy booming sound. Although at the track all out people like the sound. I will not do this on my ZL1. Instead I will do a catback that deletes the second cat which has to help with heat a little. And unless the build is big LTs are not worth that much in HP.

As to pullies if its the upper is it the largest pulley that is smaller than stock? I get confused about that.

[SJFGTO]

Originally Posted by Solid_Sim

Alright but going LT's will cleary make a much louder exhaust sound right? Wich I don't want...

What if I just change the stock cats for high flow cats?

Thanks for the answers btw guys, I might just do a small pulley upgrade to keep stock exhaust.

Yes, headers will make it louder. Forget the high flow cats. Deleting the secondary cats with an X pipe will give you a deeper but not louder sound.

[Solid_Sim]

Originally Posted by SJFGTO

Yes, headers will make it louder. Forget the high flow cats. Deleting the secondary cats with an X pipe will give you a deeper but not louder sound.

Ok now we're talking ! I'll look into that thanks

[Buzzmanb12]

Larger lower pulley or smaller upper pulley will result in more boost.

[Can'tHave2MuchHP]

Ok, so...

The exhaust itself is not restrictive at these levels. It's the cats and manifolds that are a bottleneck. You can get away with running them but you'll need to stay very mild on the build. No more than a 9% over drive pulley. So go with a 2.3 upper or so. Pair it with an intake, throttlebody. If you want a bit more work done, have the snout and blower ported by Kong and use a NW 103mm throttlebody. Don't attempt to run anything more than that. As is, you'll be overheating the cats and they'll eventually fail and ruin most of your exhaust. Seen it happen dozens of times. People want to keep the sleeper sound but want to run 600+ HP on a Supercharged vehicle that outputs LOTS of crazy hot exhaust and well, stuff fails.

Deleting secondary cats will do nothing to help this. Don't bother hacking up your exhaust to put on an X Pipe, even the Borla 60606 will require you to cut before the factory suitcase. It will increase sound and make it higher pitched, not lower pitched, and won't help address the elephant in the room which is the stock manifolds and primary cats. Having the primary cats gutted is another option but that will increase your sound substantially.

So in short, stick with a mild pulley and intake setup if retaining factory cats/manifolds. A massive misconception is that Headers can be skipped because "For $1200+ they don't add much power anyway" which is sort of correct, but they can pick up as much as 40+ RWHP on a setup that needs them with a tune. They're more of a supporting mod. They're necessary for running a good amount of boost and above. Also, headers drop your boost pressure so you'll lose 1-2 pounds on the gauge. Another big misconception is you LOST HP because of that 1-2 pound drop on the gauge. False. You just lowered the PRESSURE that that boost was under due to the restriction in the factory manifolds/primary cats which are essentially solidly packed with restrictive material. Lower pressure = more efficient = more power = less heat = ALL good things.

[Solid_Sim]

Originally Posted by Buzzmanb12

Larger lower pulley or smaller upper pulley will result in more boost.

Wich do you recommend? Wich one provides more boost/low price and reliability?

[Solid_Sim]

Originally Posted by Can'tHave2MuchHP

Ok, so...

The exhaust itself is not restrictive at these levels. It's the cats and manifolds that are a bottleneck. You can get away with running them but you'll need to stay very mild on the build. No more than a 9% over drive pulley. So go with a 2.3 upper or so. Pair it with an intake, throttlebody. If you want a bit more work done, have the snout and blower ported by Kong and use a NW 103mm throttlebody. Don't attempt to run anything more than that. As is, you'll be overheating the cats and they'll eventually fail and ruin most of your exhaust. Seen it happen dozens of times. People want to keep the sleeper sound but want to run 600+ HP on a Supercharged vehicle that outputs LOTS of crazy hot exhaust and well, stuff fails.

Deleting secondary cats will do nothing to help this. Don't bother hacking up your exhaust to put on an X Pipe, even the Borla 60606 will require you to cut before the factory suitcase. It will increase sound and make it higher pitched, not lower pitched, and won't help address the elephant in the room which is the stock manifolds and primary cats. Having the primary cats gutted is another option but that will increase your sound substantially.

So in short, stick with a mild pulley and intake setup if retaining factory cats/manifolds. A massive misconception is that Headers can be skipped because "For $1200+ they don't add much power anyway" which is sort of correct, but they can pick up as much as 40+ RWHP on a setup that needs them with a tune. They're more of a supporting mod. They're necessary for running a good amount of boost and above. Also, headers drop your boost pressure so you'll lose 1-2 pounds on the gauge. Another big misconception is you LOST HP because of that 1-2 pound drop on the gauge. False. You just lowered the PRESSURE that that boost was under due to the restriction in the factory manifolds/primary cats which are essentially solidly packed with restrictive material. Lower pressure = more efficient = more power = less heat = ALL good things.

Wow thanks for the explanation!

In the scenario that I don't want to spend on headers and really don't want the much louder noise from them, you recommend I go with a CAI + 2.3 upper pulley? How much does a speed shop usually charges to port a TB?

Considering I'd do these 3 upgrades, would I be near 700 crank HP with a tune?

[Can'tHave2MuchHP]

Originally Posted by Solid_Sim

Wow thanks for the explanation!

In the scenario that I don't want to spend on headers and really don't want the much louder noise from them, you recommend I go with a CAI + 2.3 upper pulley? How much does a speed shop usually charges to port a TB?

Considering I'd do these 3 upgrades, would I be near 700 crank HP with a tune?

Yes CAI + 2.3 upper is perfect and doable on stock cats/manifolds. As for the throttle body, just order a Katech or Tony Mamo LT4 throttlebody. Katech's are around $275 I think and Mamo's are about $390 or so. If you are interested in porting the blower and snout, you'd want to get the larger 103mm Throttlebody from Nick Williams or Katech.

CAI + 2.3 Pulley + TB + Tune should be about 610-630 RWHP to the tire. So yes around 700 BHP. I don't want to give you false hopes, you may get more than that, you may get less depending on air and dyno. It will be a SIGNIFICANT gain no matter what the dyno says. If you port the blower and snout and get the 103mm TB, I'd say 650 RWHP at least. Add headers to either and expect a 30-40 RWHP gain.

[Solid_Sim]

Originally Posted by Can'tHave2MuchHP

Yes CAI + 2.3 upper is perfect and doable on stock cats/manifolds. As for the throttle body, just order a Katech or Tony Mamo LT4 throttlebody. Katech's are around $275 I think and Mamo's are about $390 or so. If you are interested in porting the blower and snout, you'd want to get the larger 103mm Throttlebody from Nick Williams or Katech.

CAI + 2.3 Pulley + TB + Tune should be about 610-630 RWHP to the tire. So yes around 700 BHP. I don't want to give you false hopes, you may get more than that, you may get less depending on air and dyno. It will be a SIGNIFICANT gain no matter what the dyno says. If you port the blower and snout and get the 103mm TB, I'd say 650 RWHP at least. Add headers to either and expect a 30-40 RWHP gain.

Alright thanks, guess I'll go CAI + pulley + tune, but ordering a TB will cost me around 500$ canadian, wich is kinda a lot for a few hp that I won't notice?