2-1 exhaust question : V-Twin Forum: Harley Davidson Forums

zenscaper · 11-27-2005, 07:53 AM

My new to me Fatboy has a 2-1 exhaust with a tapered tip (like a dixie cup if you will). I don't know the brand, but I am trying to find out if this mod was a performance minded addition or a "looks" mod. Moreover, I don't understand the difference between 2-2 and 2-1 exhausts as they both direct and remove spent gasses.

Thanks.

csoday · 11-27-2005, 08:50 AM

If you mean these:

You are the proud owner of the best performers on the market and you need look no further.
2-1 means 2 headers into 1 collector/exhaust/muffler
2-2 means 2 headers into a crossover chamber into two exhaust/mufflers

MaineUltraClassic · 11-27-2005, 09:29 AM

Quote:

Originally Posted by zenscaper

My new to me Fatboy has a 2-1 exhaust with a tapered tip (like a dixie cup if you will). I don't know the brand, but I am trying to find out if this mod was a performance minded addition or a "looks" mod. Moreover, I don't understand the difference between 2-2 and 2-1 exhausts as they both direct and remove spent gasses.

Thanks.

Sounds like you have a Thunderheader exhaust.........which is one of the best performing 2-1 exhausts. You can see more about them at http://www.thunderheader.net. You can also see pictures of mine at the link below.

A 2-2 true dual system looks good and sounds good.........but you lose power & torque.

A 2-1 system is the best performing system you can get. It produces the best power gains as it uses each cylinder to pull the gases out of each other.

As long as the bike is tuned to the exhaust you have........you are all set.

Steve

drdevon · 11-28-2005, 03:48 PM

Sounds like you have a Thunderheader! Well done!!

zenscaper · 12-08-2005, 08:48 AM

Thanks from the FNG.

Stay Verticle

ohiomotoxer · 12-08-2005, 02:50 PM

Gotta love the blunderheader...even with it's low end bog.....

MaineUltraClassic · 12-08-2005, 04:30 PM

I have never felt any low end loss of power with the Thunderheader. It is a smooth power from idle to top end, even riding 2-up.

I did feel the low end loss of power when I put on true duals.......that was very noticable especially 2-up riding.

No complaints here about the Thunderheader...........best exhaust I've had on the bike(and I went thru 4 systems before it).

Steve

csoday · 12-09-2005, 01:37 AM

Quote:

Originally Posted by ohiomotoxer

Gotta love the blunderheader...even with it's low end bog.....

You need to learn how to tune it.

ohiomotoxer · 12-09-2005, 08:51 AM

Quote:

Originally Posted by csoday

You need to learn how to tune it.

I worked for SuperTrapp/Kerker in the R&D department for 7 years designing exhaust systems AND testing everything out there.

The Thunderheader in MY opinion is one of the best 2:1's out there even with its low end bog.

And yes, I modified the stock COLLECTOR and shortened the primaries a bit to lose the bog.

AHDRA #ET479 11.87@106mph
80cuin FLSTC, Wiseco Hi Comp Specials, Primo Belt Drive, Crane HI4, Crane timesavers, S&S hydrasolids, Belt to chain final drive, Headwork by ME, Mikuni HSR42, Pingel airshift, MPS autoshift, Dyna two step,headpipe by ME, acesgarage.com.

Totenkopf · 12-09-2005, 10:01 AM

Quote:

Originally Posted by ohiomotoxer

I worked for SuperTrapp/Kerker in the R&D department for 7 years designing exhaust systems AND testing everything out there.

The Thunderheader in MY opinion is one of the best 2:1's out there even with its low end bog.

And yes, I modified the stock COLLECTOR and shortened the primaries a bit to lose the bog.

AHDRA #ET479 11.87@106mph
80cuin FLSTC, Wiseco Hi Comp Specials, Primo Belt Drive, Crane HI4, Crane timesavers, S&S hydrasolids, Belt to chain final drive, Headwork by ME, Mikuni HSR42, Pingel airshift, MPS autoshift, Dyna two step,headpipe by ME, acesgarage.com.

Interesting! looked at your webpage.

Did you ever tear into the LSR C-style to see what makes it tick? and did you ever do any modifying to improve it?

ohiomotoxer · 12-09-2005, 10:19 AM

No, never got my hands on those ...losta reading on their site though..no powercurves though from what I could see. Point me to them if there are some out there.

Ahhh my humble web page...look out you'll get tractor fever...like I did.

Totenkopf · 12-09-2005, 11:17 AM

I saw your tractors, there are a lot of tractors sitting on the edge of farms near here that are for sale. I bet they are inside now, will check today as I'm going by there. There are A-C's, Farm-All's, Ford's, M-F's, etc. When I was a kid growing up around all the farms, I always had a fascination for them and was frequently riding on the local ones helping the farmers do their work.

My LSR has been on the dyno 3 times now but my motor still is not fully tuned yet because of dyno issues the last time out. It looks like because it is low restriction design (25" primaries and 50" overall), it is going to have a torque dip(5lbs) right around 2600 and then it is off to the races, for lack of a better term. Best estimate when fully tuned with my build, it will do 102-104ft-lbs and 97-99hp.

Never have seen RB publish any dyno charts, if you read Bob's rambings, he's not a huge believer in the value of them. He's more of a big white "dyno" guy.

I've spoken with him several times, he's a smart guy.

ohiomotoxer · 12-09-2005, 12:37 PM

Quote:

Originally Posted by Totenkopf

I saw your tractors, there are a lot of tractors sitting on the edge of farms near here that are for sale. I bet they are inside now, will check today as I'm going by there. There are A-C's, Farm-All's, Ford's, M-F's, etc. When I was a kid growing up around all the farms, I always had a fascination for them and was frequently riding on the local ones helping the farmers do their work.

Sweet !! I am looking for a Cletrac, Cleveland or Oliver crawler OR anything orchard, if you see one let me know.
I am a full blooded city boy but tractors just do something for me.

My LSR has been on the dyno 3 times now but my motor still is not fully tuned yet because of dyno issues the last time out. It looks like because it is low restriction design (25" primaries and 50" overall), it is going to have a torque dip(5lbs) right around 2600 and then it is off to the races, for lack of a better term. Best estimate when fully tuned with my build, it will do 102-104ft-lbs and 97-99hp.

Yep primaries and the collector make the world on a V Twin.
That is a decent HP number. I run so much compression on my poor ol HD, I think last dyno run was 89hp on a 80cuin.

Never have seen RB publish any dyno charts, if you read Bob's rambings, he's not a huge believer in the value of them. He's more of a big white "dyno" guy.

I've spoken with him several times, he's a smart guy.

I say you can't ride a dyno..but
Remids me of when all the AMA Pro Dirt trackers would be in town..I would spend days with them to do dyno runs and tune carbs and change things...

Totenkopf · 12-09-2005, 07:05 PM

Man! this reply is not going to be anywhere close to being related to 2-1's.

I saw 2 tractors out today with snow on'em. One was definitely a medium sized John Deere, the other was a tricycle but not a V. It was red but too dark for me to see which make for sure. Farmall maybe? Next week I'll get a better look.

I don't know Cletrac's or Cleveland's. Olivers I've seen, what distinguishes a crawler or orchard model?

Okay, here is a LSR 2-1 comment......
I know Bob uses about a 12* merge angle on the collector and the collector is shaped into an hourglass cross section shape. The street pipe version has a 7" long baffle that has a core opening completely open and about 2" to 2-1/4" in diameter, very minimal intrusion with the baffle.

gpcj7 · 12-21-2005, 10:53 PM

Quote:

Originally Posted by ohiomotoxer

Gotta love the blunderheader...even with it's low end bog.....

Who rides a TC88 at low end anyways? My 04 sport runs fine with a Thunderheader and regularly outruns 95 inch motors...even with a low end blog or whatever you call it.