RT vs GS cat code plug differences?

[chrisz]

Hi all,

 

Can anyone tell me what the differences are between cat code plugs on a 2002 RT vs a same year GS? I know the intake tubes are different, but would expect the cat code plugs to be the same or at least similar.

 

Thanks in advance,

[Haynes]

In Australia, both models come without the CCP. I believe that the USA and Canadian versions of the RT had the pink CCP and the GS had the olive green CCP.

Both my 2004 RT and my 2003 GS run perfectly without the plugs.

[Joe Frickin' Friday]

The two engines breathe differently, as evidenced by the different torque curves; the breathing is a result of the valve timing and intake tube geometry. As they breathe differently, the two engines will have different open-loop fuel maps, and will likely have different ignition timing maps as well.

 

I suspect that the GS ignition map will be deliberately retarded from MBT spark timing so as to accomodate the lower-octane fuels one finds in backwater locations. Note that this may not be the case with the R1200 bikes, which come equipped with knock sensor(s).

[chrisz]

The two engines breathe differently, as evidenced by the different torque curves; the breathing is a result of the valve timing and intake tube geometry. As they breathe differently, the two engines will have different open-loop fuel maps, and will likely have different ignition timing maps as well.

 

I suspect that the GS ignition map will be deliberately retarded from MBT spark timing so as to accomodate the lower-octane fuels one finds in backwater locations. Note that this may not be the case with the R1200 bikes, which come equipped with knock sensor(s).

 

Would it make sense that if one replaces the RT intake tubes with the GS intake tubes (on an RT), one should also replace the cat code plugs? Me thinks, yes.

[Joe Frickin' Friday]

Would it make sense that if one replaces the RT intake tubes with the GS intake tubes (on an RT), one should also replace the cat code plugs? Me thinks, yes.

 

An RT motor with GS intake tubes is Frankenstein's Monster: it may have the tubes from a GS, but it's still got the RT's valve timing and compression ratio. With such a beast, neither the RT CCP or the GS CCP is a perfect match. But two thoughts (again, speculation) come to mind:

 

1. The GS has more torque (breathes better) over most of the lower part of the RPM range, breathing slightly worse than the RT near redline. If the Frankenbike's breathing at low- and mid-RPM's is somewhere between that of a GS and an RT, then the GS fuel map might help it to run rich under those conditions (when in open-loop mode), whereas the RT fuel map might make it run lean. All else being equal, slightly rich is safer than slightly lean; it'll help to keep temps down and reduce ping tendency.

 

2. If my theory about ignition timing is correct (GS uses retarded timing), then the GS CCP might be a solution for a Frankenbike that's experiencing knock/ping problems (because of the aforementioned weird fuel mismapping).

[steveknapp]

Can anyone tell me what the differences are between cat code plugs on a 2002 RT vs a same year GS?

 

2002 = 1150RT.

 

Keep in mind, the CCP colors all changed around for the 1150 bikes. So what you read about an 1100, like "use the yellow" does not apply on the 1150.

[DavidEBSmith]

If the Frankenbike's breathing at low- and mid-RPM's is somewhere between that of a GS and an RT, then the GS fuel map might help it to run rich under those conditions (when in open-loop mode), whereas the RT fuel map might make it run lean. All else being equal, slightly rich is safer than slightly lean; it'll help to keep temps down and reduce ping tendency.

 

On my 1100RT (a different Frankenbike), I get better gas mileage with GS tubes + GS cat code than with GS tubes + RT cat code. Seat-of-the-pants says that the acceleration is maybe slightly livlier (but not enough to really care about) with the RT cat code plug than with the GS cat code plug (with GS tubes). I've never noticed a pinging problem with my bike with any combination of tubes and cat code plugs. I'm been using the GS tubes and GS cat code plug for probably 100K miles. So what does all that mean? I dunno.

[Joe Frickin' Friday]

On my 1100RT (a different Frankenbike), I get better gas mileage with GS tubes + GS cat code than with GS tubes + RT cat code. Seat-of-the-pants says that the acceleration is maybe slightly livlier (but not enough to really care about) with the RT cat code plug than with the GS cat code plug (with GS tubes). I've never noticed a pinging problem with my bike with any combination of tubes and cat code plugs. I'm been using the GS tubes and GS cat code plug for probably 100K miles. So what does all that mean? I dunno.

 

Might mean I'm fulla crap on the spark timing thing. Maybe the 1100/1150GS accomodates low-octane fuel strictly by the reduced compression ratio, and the spark timing is still at or close to MBT timing?

 

re: the pinging...lucky you, no carbon buildup problem (or maybe you're not twisting the Loud Handle far enough ). I had terrible knock on mine after I switched to GS tubes; after playing with fuel additives and manual cleanings, I finally found that a steady diet of WOT keeps the ping in check.