chipping? - Horizons Unlimited

**indu** · #1 23 Jul 2002

Just a thought:
BMWs like the 1150 GS, R and RT basically have the same motors, right? While the GS and R models have a max output of 85 bhp/97 Nm, the RT have 95 bhp/100 Nm. Now, let's say you want the RT output on your GS: Is it possible to re-chip your GS to attain this?

Safe journey to all of you out there.

Indu

**nick_horley** · #2 23 Jul 2002

I think they also have different cams. Not sure how big a job it is to change them, but I don't see why it couldn't be done. You'd gain some top end power but you'd lose some in the midrange. Could you tolerate that?

If you want to know more I could ask a friend of mine who is a BMW technician.

Have you removed the cat from your GS? If you want more power I would say this is the first thing to consider.

**bigblackfalco** · #3 24 Jul 2002

Yeah,Nick is right;the camshafts are different.
The GS and R's use the same camshaft.
The RS/RT share a camshaft which gives more valve lift on the exhaust side for a longer duration.
They all utilise the same valve sizes though.
Torque ratios are:
GS 97Nm@5250 rpm
RS/RT 95@5500 rpm
Power ratios are:
GS 59kW@6750
RS/RT 66kW@7250

So it's just a matter of deciding if you want to loose that low down grunt to gain 7kW!!
Personally I'd just spend money on K&N air filter/Race can/chip and gas flow the heads!!!
Cheers
Bailey.

**nick_horley** · #4 24 Jul 2002

I used to have twin race cans (custom made by MHP) but couldn't stand the noise, so went back to the stock can but without the cat. And I bought a very expensive Wunderlich chip and, 18 months later, still haven't fitted it. Been meaning to go to a dyno shop, test the chip and play around with some airbox mods, but never got round to it. Not even sure where my cat is - probably threw it out, so missed my chance to do a back to back test. All in all a totally shambolic project. If anybody here is serious about tuning their GS it might give me just the kick up the arse I need....well????

**nick_horley** · #5 24 Jul 2002

While we're on this subject, does anyone fancy a turbo GS? Check out www.rbracing-rsr.com/bmwturbos.htm

You know it makes sense.

**indu** · #6 24 Jul 2002

That turbo thing is one mother, or what?! Wouldn't that be cool, having one of those installed in your average R1150R, GS or even C, beating everything from Ducatis to Hayabusas ;-)
Then again: I feel quite comfortable with the output on my 50R. I just wondered if it was possible to do something like re-chipping. I'm not striving for more power. In that case I'd buy a different bike, I guess. Or add a turbocharger...

Ride safe

Indu