3 into 1 exhaust for GT380

[eithr]

Getting ready for some winter projects to keep the momentum going on the GT380. Curious if anyone has any experience or thoughts on replacing the stock 3 into 4 exhaust system with a 3 into 1. The advantages I've read about suggest that the 3 into 1 system will shave off a significant amount of weight visually and actual, as well as improve fuel consumption. I've also read that it should improve the power range in the lower and mid range.

Going with a 3 into 1 would I need to rejet?

On the flip side... if I were going purely for more power and better performance, would I want the 3 into 3? I'm guessing that would require rejetting and would probably worsen fuel consumption. But let me know what you think and correct any of these rumors. Thanks.

[hombre]

I was wanting the same for my gt550. Or just something less flashy then the stock

[tz375]

Basically that's the case. 3 into 1 pipes tend to boost the bottom end, they lose a ton of weight but often flatten the top end somewhat. 3 into 3 will tend to boost power around peak torque/peak HP revs and will tend to lose out lower down. Those are huge generalizations of course and a badly designed pipe can lose power everywhere. Just as much as a well designed pipe can make a bike more fun to ride.

Back in the day, SI used to claim that their 750 3 into 1 added 5 hp at the top end. SO far I have seen no dyno tests to prove or disprove any of the theories, but lots of anecdotal seat of the pants evidence and even more opinions.

[eithr]

I was curious about the pipe's on Omar's site. He has a 3 into 1 pipe on there, but no description for the GT380 model. For the 750 model, he mentions improved fuel consumption and the improved lower and mid range power. These ideas all sound awesome to me. I mostly ride the bike in an urban setting, but do occasionally hit the interstate... with a less exciting top end, I'm guessing I'll just need to shift sooner to keep in the low to mid range revs, right?

And, improved fuel consumption sounds great. Currently, I'm getting between 25-35 mpg.

Has anyone heard anything or have any personal experience with Omar's 3 into 1 pipes?

[Craig380]

I've just sold my Piper 3-1, I used it for a year or so then went back to the stock pipes. Bear in mind that the pipe was designed in the 70s, and was made more for looks and to fit the fashion at that time for 4-1 pipes on 4-strokes, than for optimum power.

Advantages:

- the awesome sound (try http://www.youtube.com/watch?v=P79w18ggTyM" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; and http://www.youtube.com/watch?v=XfHmJA9aQas" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;)
- weight saving (the Piper weighed 8 pounds, about the same as a single outer factory pipe)
- great looks
- rideability is still good in urban / medium pace riding (i.e. around half throttle and up to 5,000rpm)
- the awesome sound

Disadvantage:

- the pipe stops the engine revving beyond 7,000 in ANY gear -- which means your practical top speed is around 80mph. Mine would just get to 7,000 in 5th (about 80mph) but wouldn't pull 6th gear at this speed. So it definitely robbed top-end power (stock engine, carbs & airbox / filters).

Fuel consumption wasn't noticeably affected. I didn't need to rejet, I found that it just needed the pilot screws leaning out by a quarter turn. Possibly I could have got more revs by playing with jetting / airbox etc, but I couldn't be bothered. The bike ran cleanly & well with just the small tweak on the pilot screws, so I figured it was simply the characteristics of the pipe that was strangling the top end.

In conclusion, I loved the look and the noise of the 3-1, but preferred the extra power available with the stock system.

[iagsxr]

Omar's pipes are made by Jemco. Call them. They've been helpful to me.

[markj]

Wayne M. has a 3-1 on his Buffalo. I think it's a TC exhaust like mine. Anyway I haven't run mine yet but maybe he could give some input here.

[Turtle]

I have a 3 into 1 exhaust for a GT380 in my shed.... but it is in Brisbane Australia and it is for sale.

[iagsxr]

Not to jack, but...

I'd like a 3 into 1 for my 75 550 if anyone has one.

[eithr]

So, the 3-into-1 pipe should be fine for normal riding. I usually cruise around 70-80mph when on the interestate... but I'm guessing that a 3-into-1 would elminate my desire to someday 'ton up' on this bike.

Is there a significant negative effect on fuel consumption with a 3-into-3 set up?

If I want to keep the bike's wide powerband as is, is the best option to keep the stock pipes? Despite their bulk and weight?