Forgive me if this has been covered--I'm kinda new at the Harley performance thing...

I've got a 09 FXDC that I recently purchased used with a Cobra Speedster exhaust, a SE Stage 1 A/C, and a HD "Digital Technician" remap. The Speedster exhaust is similar to the V & H BigShots in that they have a balance pipe that connects the 2 pipes.

I haven't had the bike very long but I'm already thinking I need more power, especially for 2-up riding. I'm planning on a cam upgrade (Andrews 48 maybe?) and a real tune, but I'm happy with the current sound and look of the exhaust, not to mention I already own it.

How much power is the 2-2 exhaust actually going to cost me compared to a decent 2-1 system? I understand that there is a ton of variables and that no two engines responds exactly the same, but as a general rule are we talking like 5hp or like 15hp? Basically I'm trying to decide if I should budget for a new system.

 

I'm sure djl or someone more knowledgable will chime in and perhaps be able to give some swag numbers, and others will chime in with opinions, but for now here's mine:

- You like the looks and sound of your current exhaust
- You are running something more than stock
- You are not chasing max performance numbers
- You are looking for a bit more power
- You are going to install better cams

In my opinion, you would be best to stick with what you currently have, given those critiera, and instead spend the money to buy a TTS or SERT and have your bike dyno tuned by a good, reputable tuner. You'll be getting great gains from the cam upgrade, and getting it tuned right for the combination should result in a very satisfying bump in performance for you, solo and two-up.

JMHO

Roger

 

I know nothing about the Cobra exhaust but V&H introduced the "power chamber" thing years ago to try and convince us that we could retain the 2:2 look but with 2:1 performance which is great marketing but not accurate.

Noone can say with certainty how much more TQ/HP you would see from a good 2:1 system but it will be closer to 5 than 15.

I do not know what a "digital technian" remap is but it sounds like the Stage I ECM flash. You will see more gain with a better fuel management system like the SEST or TTS.

If you go ahead with the cam upgrade (the 48 is an excellent choice) I would agree with the Tunaman logic of passing on spending money on the pipes and invest it in a good fuel management system and a dyno tune. Don't forget to upgrade the inner cam bearings while you are in the cam chest.

 

Thanks for the replies.

I'll probably stick with the exhaust I've already got. I'm ok with knowing I'm giving up a few horsepower over a 2-1 system.

I don't know what a "Digital Technician" is either, but I'm assuming its the standard dealership "stage 1" remap. Thats just what it says on the invoice the original owner had in his files.

 

I have used twin duals (not connected to each other) and a 2-into-1 system on the same bike and had them both dynoed. I actually lost 1HP with the 2-into-1, but gained approaching 15TQ in the low/mid range. Not surprisingly the bike runs much better when 2-up, because of the improved torque curve. The loss of power is insignificant and not worth worrying about!

You don't need power for riding 2-up, but torque. My SuperTrapp Supermeg 2-into-1 is a great system and not too noisy. The bike runs much smoother and sweeter, as well as being stronger over the rev range we mostly ride in.

 

I don't think your 2 into 1 into 2 is suffering a whole lot on the performance end, but a 2 into 1 will up torque, get rid of Harley's readily available flat spots, and just maybe make more HP.
In my case, as an example, 95"/10.2cr with 316 Crane cam (510lift, 242/252) with SE slip ons, stock carb, it did 78.8HP/92T. A change to a V&H Pro Pipe/ 42 Mikuni jumped those numbers to 92.6Hp/98T. T was flat 98 from 2700 to 6000rpm, 128 mph!! Fastrider124