Slip on exhuast vs a full system

[Nick24601]

I'm torn between getting a Carpenter Racing full exhuast system or a slip on. I've read you get enough noise out of the slip on without silencers to match the sound of my now wrecked Harley and I like the look of it with those carbon fiber shrouds a lot. What I'm worried about is leaving extra performance on the table. I talked to carpenter today and they don't believe anyone is going to Crack the new ecu's anytime soon.

What do you guys think? Will a full exhaust system out perform a slip on? He also told me to "get those plastic things" for the airbox to make the air flow in better. No idea what those are. Also no idea what filters to get.

 

[gadget_ho]

You are not going to get many horsepowers more out of the Rocket with any exhaust I don't think, as the ECU adapts in real time to operating conditions. Aside from the Meerkat Mod that frees up flow through the cat, the other main restriction on pushing out the exhaust gases is actually the headers, and the max size those can be is limited by the exit ports in the head. You can see that in the custom headers that both Carpenter and Vandemon sell as they don't look much bigger.

That being said, TTS gets some pretty big numbers, seemingly without much exhaust work, so YMMV...

 

[Gimlet]

Unless the 2024 onwards Storms are different, as far as I'm aware the ECU can be over-written. Plenty of dyno shops offer custom mapping on Rocket 3's with restrictions removed.
You wouldn't be able to supercharge or turbo-charge an R3 without loading a radically different map.

You're not going to achieve anything more than small performance gains by fitting a slip-on can when the headers are so restricted. A slip-on is worth it if you're looking for better looks, better sound and to shed the weight and heat of the cat. For outright performance you need a full system and by the sound of it possibly head porting as well.

If no full system which I'm happy with comes on the market soon, I'm considering fitting a modest turbo-charger to mine with a custom exhaust system. If you're going to have a one-off exhaust system fabricated you might as well put a blower in it. A modest 6-8 psi of boost would give significant gains without extensive engine work.

 

[Nick24601]

A TTS would be at least 2 years out unfortunately. Thanks for the post, your really reaffirming what I thought. I even looked at TTS's videos and yes, they modified the headers. Would be interesting to see what a pro could squeeze out of a tts settup in the quarter. They only got it to a 10.2, but a pro got a stock one without a quickshifter to 10.5...

 

[Gimlet]

A TTS would be at least 2 years out unfortunately. Thanks for the post, your really reaffirming what I thought. I even looked at TTS's videos and yes, they modified the headers. Would be interesting to see what a pro could squeeze out of a tts settup in the quarter. They only got it to a 10.2, but a pro got a stock one without a quickshifter to 10.5...

I'm waiting to see what full system Paul Bryant comes out with. If I like the look of that I'll try just an unrestricted exhast and custom mapping. It could be that that will be enough. Staged tuning is the way to go IMO. Chasing ultimate numbers in one go is not. Every gain involves a trade-off somewhere else, such as rideability, running costs, maintenance etc. Everyone needs need to find their sweet spot.
I won't be going for a supercharger. It's too much money and I'm not convinced that for me it would be the best method of forced induction for the way I ride what is an inherently high torque and relatively low revving engine, as superchargers are actuated by engine speed. A turbo is controlled by throttle opening regardless of revs. And it's cheaper to install, maintain and run. Of course if you won't settle for less than the huges gains of a supercharger that's a different matter, but I don't think it's the right route for me.

 

[Idaho Red Rocket 3]

Paul Bryant at Viking Exhaust New Zealand has a new full system available now for the 2.5L Rockets. Get in touch with him. I have one of his full systems on my 2.3L Rocket. Good stuff. Good numbers. Good sound.

 

[Gimlet]

I wish he'd update his website so we can see what it looks like. Facebook is saying his content is unavailable.