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2 into 1 a better performing exhaust?

10551 Views 19 Replies 8 Participants Last post by  Fulltilt1
want to change my cobra slip ons on my 2003 v-star 1100 but cant decide on wich one...2 into 1 or a 2 into 2.....u guys know wich be a better performing exhaust ?.....have read that the 2 into 1 is
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2 into 1 or 2


I think 2 into 2 looks better but I understand 2 into 1 gives slightly better low end torque.

It would be hard to tell which exhaust is better without doing a dyno run on each. But as rumor has it the 2into1 does give better performance. Of course I have the ShoGun 2into2 exhaust which still gives good preformance upgrades.
With the new 2 into 2 pipes coming with "power ports" / "equalizers" or crossover tubes (kinda like the X-pipe they use in Nascar) the difference is negligible. So if you're shopping just look for those type pipes and then you can just shop looks or sound. At least it takes one of the variables off the table.
i gues that tells u right there huh...if they designed a 2 into 2 to work like a 2 into 1 then the 2 into 1 gotta be a better performer
I got cobra 2-1 HP exhaust on mine as well as a max air kit.

All i can say is the bike is a BEAST now. MUCH quicker than stock with WAY more mid range grunt.

Itwas a pita to get fueled right (still not 100% there gotta book a dyno). But the rewards in performance are asstounding.

The bike is a bit louder than i really wanted but its still not deffening and has a hell of a mean bark to it.
Actually I guess it means they were a better performer... Now all things are equal.
did the max air kitt come with jets for stock exhaust and full exhaust mod?....i thinking of going with HARD KROME 2 INTO 1 SIDEBURNER exhaust and the chubby air kit from SS custom cycle ....so u saying the jets they provide wil not tune the carbs?
These tables are pretty accurate as to the jetting sizes and settings. The Chubby kit uses RU-600 K&N filters and are larger /better flow than the Max Air. Thats the POD filter used in these tables. These are Mikuni size jets.


If you happen to get Dynajet jets here is a conversion chart to match them to Mikuni. Most will tell you Mikuni are the ones to get, flow like they're meant to by manufacturer.


One other thing if you decide to put your kit together yourself it can be done for about $100. If you do that you'd have to dig for this tidbit... You have to switch the rubber boots from carb to air filter front to back to get the required clearance. When you remove them you'll see they are different heights.

If you tell Shane at S&S what you are doing he'll set it up right (the kit that is)
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did the max air kitt come with jets for stock exhaust and full exhaust mod?....i thinking of going with HARD KROME 2 INTO 1 SIDEBURNER exhaust and the chubby air kit from SS custom cycle ....so u saying the jets they provide wil not tune the carbs?
When installed my Maxair Predator kit, I believe it came with the jets and any other necessary parts and instructions to do the job.
Yeah mine came with the jets and such but for some reasone it still dont quite get enuf fuel at the top end of 5th. ITs not really a problem so i not tooo concerned about it but its something i want to clear up for those trips to the drag strip to run against my buddys dodge dart (i think i gona loose but its still good fun).
2 into 1 sometimes looks nice but always DECREASES PERFORMANCE!!!!! engines need to breath power and performance very simple and inexpensive to increase THE MORE AIR IN THRU THE CARBS THE MORE AIR YOU WANT OUT THE EXHAUST. less restriction the better. best for just performance exhaust individual pipes per cylinder and the shorter the length the better. but remember you also want to put passenger on to short exhaust runs up their leg. 3/4 is more effiecent length and you want the biggest diameter you can use also. simply jetting and exhaust will give u al least 10 hp. alot for a bike. if fuel injected download adjustment directly into power commander cheap and nothing to buy maybe the connector. good luck. be safe
1 more thing dont waste money on performance air filter. the air box to dress up bike ok but little secret stock filters are more effiecent because their not as thick and restrictive as performance filters. trust me know what im talking about dealers and vendors just want to sell u crap.
did you get a jet that was shorter than the others? or even better the diameter of the little hole on jets the igger the hole the slower top end. and vise versa. unless you change sprocket or drive shaft pionion gears. really the money spent to performance gained best bet use the jet (not sure #) thats for slight performance. check the specks that came with the jets.
2 into 1 Hands Down

I have an 06 RS. I but the Cobra 2 into 1 HP. I had them installed at a local shop. Rejetted my carb. Ran a dyno before and after. If there is no difference I guess the dyno was wrong. The torque and hp jumped greatly. 2 into 1
Tiny you do know that these bikes are speed limited for a reason. Not a good one though, the nannies just want you safe.
SwampStar if you want performance open up the intake with a POD setup and rejet. Let those pipes breathe. Here's a link to what mine looks like.

Yes i know its limited to keep me safe. But i like to make a few runs at the drag strip each summer so its run to its upper end in a safish manner.

Besides this bike even modded is still relitivly slow in comparison. My old 650cc suzuki was much faster and it was more a touring bike too.

Still yet to get this thing to the strip no time this year so far.
Old Paul

Seems to me that going 2 to 1 is more restrictive than 2 into 2, unless the pipe diameter is 2X greater or more. When you restrict gas outflow you increase low end torque but decrease high end torque and power. It tends to screw things up even more when you have increased fuel/air inflow by rejetting, (unless you used smaller jets). You get more air/fuel in and less air/fuel out and more back pressure. On the up side your back rap is much better-then again, back rap does not increase performance.
Most of the 2 into 1s have a huge dump, so theyre not restrictive at all. Youre right about the torque and hp. I prefer the 2 into 2 with a crossfeed, best of both I think. All exhaust systems are a compromise unless the exhaust is an active one that can change backpressure/flow for conditions.
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