2 into 1 exhaust experience

Doug Lofgren did a bit of dyno work with 2-1 and they just didn't make any power. So if someone comes up with a 2-1, they'll need to do a lot of R&D to get pipe diameter and collector location perfected. Oh, and you might blow apart mufflers... TBR made a TL1000S 2-1 system and it would literally blow the muffler apart.

And I totally agree with you about the Sil / FbF 2-1 for monsters. SEXY.

;D

chris said:

Doug Lofgren did a bit of dyno work with 2-1 and they just didn't make any power. So if someone comes up with a 2-1, they'll need to do a lot of R&D to get pipe diameter and collector location perfected. Oh, and you might blow apart mufflers... TBR made a TL1000S 2-1 system and it would literally blow the muffler apart.

And I totally agree with you about the Sil / FbF 2-1 for monsters. SEXY.

;D

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But did it make any less power? I was part of a shop team years ago that was working on a 250cc 4 cycle race bike and we made our own custom exhaust using a dyno. It was impressive. At one particular setting the rear wheel horsepower doubled at WOT. No ****. We didn't believe it at first either but we could repeat it over and over. The MIG machine was brought in and we tacked it together right on the dyno stand.

That was at WOT though. I always thought that the "round about crossover junction" on the Monster was a bit funky but I have no complaints about the power. (Well............ nothing that the exhaust would fix anyway) Now, in the day to day world would we actually lose power by running a 2 into 1? This is what Lofgren suggests due to the large volume pulses the twin generates. (Small volume pulses from a 4 cylinder do OK) but from actual dyno or riding experiences is there an actual power drop? If so how much and is it across the board or just at high end?

Read for yourself
http://www.visi.com/~moperfserv/2into1.htm

I see. Thanks. It looks like a very slight loss of horsepower / torque vs. aesthetics / weight.

kopfjager said:

NCR runs a two into one with the 1000ds engine, I watched Mike Smith race it last week and he walked a couple 748r's and a 675 like they were standing still!!

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Hahaha, Well, if Jeff Nash or Mark Hatten (?) were on the 748Rs, that would mean something! Coming off the turn with a few mile per hour more does that pretty handily.

1000DS is apparently pretty easy to get to 100hp, too.

Honda RC51's had 2 into 1 toward the last season(s) of their AMA and WSBK. If the results of 2 into 1 on the 250 discussed in the article about making more power at WOT hold true for a 1000, it would make sense that Honda would switch from the original 2 into 2 to the 2 into 1 for a racing application.

I had a ducati rep tell me that the factory was able to get better power out of the 750 engines with a 2-1 exhaust vs. a 2-2. He said the 900's preferred the 2-2. Do not know how accurate this is but just what I was told.

needtorque said:

I had a ducati rep tell me that the factory was able to get better power out of the 750 engines with a 2-1 exhaust vs. a 2-2. He said the 900's preferred the 2-2. Do not know how accurate this is but just what I was told.

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Well, I've seen a lot of stuff that just doesn't make sense. Especially with the 900 2Vs. Intuition doesn't apply to them! ;D That's why folks like Doug L and I (though I would humbly say I'm not really in the same league as he) that until something is tested in a way that can quantify the change, you just don't know what will happen.

It's like the 966 pistons for the 900s. I have done by my own hands 2 different big engine builds: one 944 and one 966. And the 944 engine was 6hp down compared to the 966. And I did everything I could to make the 2 builds (and bikes) identical. Either there's something special about an extra mm in diameter that's happening in the combustion chamber or the bikes are just different.

kopfjager said:

NCR runs a two into one with the 1000ds engine, I watched Mike Smith race it last week and he walked a couple 748r's and a 675 like they were standing still!!

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yep, saw them too... these things are a bullet.