Y=piece question

[L]

I've just had my old y-piece installed on my Turkish 1150GSA and when the local "Steptoe" saw it, he rolled his eyes and proceeded to explain that its not good, because a) the temperature runs at 160degrees instead of 110degrees and torque is lowered to about 80Nm instead of 90Nm. I always thought the Y=piece improved performance, so who's right?

 

[Dickieboy]

I haven't got a clue about the technicalities and specs lI do know my 1150 runs and feels nicer with cat on though.

 

[ian6760]

Again I don't know the numbers, but when I fitted mine, it improved the mid range but felt like a little less power at the very top end. Personly this suited me down to the ground as I never seem to go above 5.5K RPM.

 

[Aidjay]

I had my cat converter replaced with a Y-piece about 6 months ago and it improved my bike's performance hugely (R1150 GSA).

There's way more low down grunt, but it felt like there was improved performance through the whole range, and sounds better to boot. The bike does probably need a retune as it occasionally backfires when you blip the throttle (which is handy for announcing your arrival).

It would make sense that the pipes would be hotter, but is this necessarily a bad thing?

Fuel economy is also slightly better, but only if you don't blip the throttle too often, which I'm prone to doing these days.

And reducing your bike's weight by half a ton, which is roughly what that cat converter weighs, is also not a bad thing.

 

[sproggy]

It makes no sense to me that a y-piece that offers little resistance to gas flow would get hotter than a cat which does offer resistance. Cats only work when they're really hot anyway so it needs to be hot.

Wunderlich offer a 'sport collector' which is a bit like a cat without the innards - it has a chamber which is supposed to increase the mid-range compared to a y-piece. But I've never heard of anyone who's tried one so I don't know how effective it is.

I suspect that the y-piece will improve performance at higher revs (less resistance to gas flow) but less so lower down the rev range. My bike runs smoother with a cat than with a y-piece but the seat of my pants isn't sensitive enough to tell a performance difference. Without a cat the bike makes more noise which may make the bike 'feel' quicker to some people but I don't think a dyno would show much difference.

 

[Steptoe]

that its not good, because a) the temperature runs at 160degrees instead of 110degrees

Ask him how he works that out. As sproggy states, a cat needs to get very hot to work. Hotter than a Y piece.


And don't measure the temperature just by feeling the metal. The cat is multi layered, a Y piece is single skinned.

It will alter the torque, but mostly by altering where it peaks and troughs in the rev range, not outright torque values.

 

[Onwalkabout]

I have one of these so called 'sports collectors' - I picked it up second hand while looking for a Y-Piece. I had no real intention of getting this specific item, it just fell in my lap so to speak.

Not having a standard Y piece for comparison, I can only comment that the mid range was improved and, more importantly, that annoying surge you sometimes get simply disappeared. Out on the autoroute at 120 Kph it pulls well in 6th (overdrive spec) and generally feels smoother than with the original cat.

 

[L]

Ask him how he works that out.

My Turkish isn't that good!

 

[ronnie69]

My Turkish isn't that good!

how do you know he wasn't saying " these y pieces are feckin great - you want to get yourself one of them, you do, instead of messing about with these daft catalytic converter doofers "

 

[L]

how do you know he wasn't saying " these y pieces are feckin great - you want to get yourself one of them, you do, instead of messing about with these daft catalytic converter doofers "

My Turkish isn't that bad!!

 

[chad]

My Turkish isn't that bad!!

 

[nick.ct]

Maybe your mate means that the silencer will run hotter with the Y piece, which is in fact the case. The Y piece and the CAT will both be very hot anyway with the Y piece warming up quicker that the CAT coz of its lower mass.

Nick