R1150R Brad’s bike – From Std to Hot Cams, Including Pipes, Ducts and Eproms

Believe it or not, a full report based on one bike! Woo hoo. Good to get away from bike to bike comparisons.

When I first bought the R1150R, I had some cams Lennie at Boxer Performance had supplied for testing in the R1100S. In the S they were nice, but just not really different enough from std to be saleable. This would, I thought, make them ideal for the 1150R.

So, when Duane had done the eprom development for the 1150R with the Staintune exhaust, I went down and pulled the std cams, replacing them with the Boxer Performance ones. I also fitted the shorter, larger diameter air box to throttle body tubes from the RS/RT. These are about half the length of the R/GS tubes, and quite a bit bigger in diameter. We left the rest as it was, and Duane mapped the combo.

The result turned out to be not quite what I was expecting. Initially, this was because I was comparing it to another bike with pipe and std cams (Harold’s GS Adv) and next to that one it looked pretty lame. In the 1100S, these cams lost a touch through the mid range and gained a couple at the top end. So I figured in the bigger 1150 motor they’d work pretty well. The valve sizes are all the same, as are the ports and throttle bodies. I was hoping for mid – high 90’s power wise, but the lower compression of the R/GS engine would knock this back a touch. So low – mid 90 became the realistically hoped for target. Duane was a bit sceptical when I told him I was expecting 10 more (I knew a std cam with pipe bike would make 84 ish), but when he went for a ride after the cams went in, he was pretty impressed with the increased top end.

When he bought the bike back, I took it to the dyno with Harold and his GS Adv for some runs. We ran the GS first and then put mine up. The 10 hp at the top end we got, but the comparison to Harold’s GS (std cams, Leo Vinci exhaust) put a bit of a dampener on things. So I’ll show you the chart first. Red is the R with the BP cams, green is H’s GS. Power first, then torque.

At that point, I was pretty let down. But, I continued through the process with my bike, eventually returning it to std after running it on the dyno through each configuration. So, I’ll start at the start, so to speak. Although in this case, it was the end, as I started at the final (“hottest”) configuration. When I finally got to test mine in the same trim (std cams with pipe and chip) as Harold’s I was somewhat less depressed. I had this report already written before I got to test my bike with std cams, so had to pretty much re-write it afterward due to the results. It’s a habit – I actually have the “851 with 944 engine” report already written, even though that engine is just a collection of bits and ideas. Some of which will change. Helps me think things through and clarify (ie, change) my ideas. The next graph compares my R with Harold’s GS in the same state of tune, just because it’s the easiest place in the story to put it. But, I suggest moving onto the following graph before making too many judgments based this one. The differences between the two bikes are the exhaust brands (Leo Vinci and Staintune) and the kilometres. Mine had 3,800 on the clock, Harold’s over 17,000 when these runs were made.

Anyway, back to the start with my R1150R. In the previous report there is a graph of some std 1150R and GS runs comparing them. To that graph I’ll add my bike to show how it compares to the others. In a word, not too well - at 5,500 RPM it’s 6 hp down on the best. But that’s how it is, so, while it’s good to know, it’s ultimately irrelevant. And it puts my mind at ease a little re comparisons with other bikes. The red, green and blue curves are from the previous report, where I made the comment that the red curve was a little lacking. Well, my bike is the yellow curve! So the question is, how good was Harold’s GS std? Dunno, wherein lies the problem with the previous graph.

Moving on, the next logical step is to add an exhaust – in this case the Staintune full system, which is a collector box and muffler. Fitted with an eprom to suit (Ultimap UM872) to an otherwise std bike, the system gives a nice increase through the RPM range. Similar curve shape, just more of it. Although the Staintune, as compared to the Leo Vinci on Harold’s bike, does have a little kick in the curve from 7,000 to 8,000 RPM (see the graph above). Probably due to the differing collector designs, and something not many owners will really worry about I’d expect. The graphs below show all std in green, Staintune system and UM872 eprom in red. Power first, then torque and air/fuel.

Lots of posts on forum sites I’ve seen have guys with R or GS saying the only advantage you get with a pipe is more noise. I really don’t understand that riders can’t feel this sort of increase, but it depends how you use it I guess. The bike is certainly pretty punchy in all std trim, but adding the pipe and eprom really bring it on.

Next I did what many owners do – play with the air duct lengths. By air ducts I mean the ones between the airbox and throttle bodies. This is a fairly common mod, and can be quite comical. There are two std types of duct. The RS/RT ones – with diameter tapering from 51mm up to about 57mm, and about 120mm long. The GS/R ducts are about 48mm diameter all along their 250mm odd length, and are actually two separable pieces. Very different. Guys with RS/RT fit the GS/R ducts to get more midrange. Guys with GS/R fit the RS/RT ducts or shorten their std ones for more top end. But the testing I did really bore out something – the std 1150R/GS cams work very well with the long ducts in the state of tune they’re designed for.

There are two things you can do with the std long ducts.

1. Separate the two pieces (preferably using a screwdriver as leverage while trying to pull them apart, eventually managing to stab yourself in that nice fleshy part of your palm where the thumb activating muscle is, just like you knew you would). Probably best done getting someone else to pull on the other end – they are a very tight “molded tang in hole” type fit. This leaves a step at the entry end.

2. Cut the tubes in half at about the join, then round the end off for good air entry.

You’d think option two, with the nice rounded entry bit, would work the best power wise, but I found otherwise when I was doing the testing with the hot cams fitted (I’ll show you that graph later). Save yourself the work and just pull them apart is my advice.

So, to the next graphs. To the previous graph we’ll add a blue line, being cut down air ducts with rounded air entry end. As you can see, shortening the ducts really drops the midrange, although it does stop the top end drop off, effectively extending the power band of the engine right up to the rev limiter. On the road, I noticed the top end gain more than the midrange loss, but that could be just the way I’d changed my style to suit the bike (remember, I started with hot cams, then went back to std). But it does show that the long ducts are an important part of the std engine tune. Personally, I don’t understand why they didn’t use this engine in the RT, but that’s life. It really is a punchy engine, one that excels in corner to corner acceleration. So even if you do stuff up your corner entry, there’s still plenty of grunt to help you get away with it.

Power first, then torque and air/fuel. You can see the air/fuel trace is richer in the midrange for the blue curve compared to the red (same UM872 eprom), simply due to less air being trapped in the cylinder, while it leans out at the top end when it starts making more power. As you’d expect.

So, a little less punchy in the middle, but better at the top end. At the drag strip (something I’ve just starting doing for a different kind of fun), the difference is mainly in terminal speed (MPH). What you lose in first gear launch and acceleration (60 foot time) you gain as once over 6,500 RPM in first you have a flat power curve to use in the higher gears – you don’t go below 6,500 RPM again. I picked up 4 or 5 mph through the traps, while running the same elapsed time – around 12.3 seconds. Funny how drag racing works sometimes.

The next step up (where I started) is some hotter cams. As I said, I had run these cams from Boxer Performance in my R1100S, and figured they’d work well in the R. Although the starting points are somewhat different – the R/GS run different cams to the RS/RT/S that give more midrange – so I had more to lose there, as it turned out.

The combination Duane mapped was BP cams, Staintune system and RS/RT air ducts. We had to settle on one, and that was the best “overall power” combo as far as I could tell. This was what gave the initial mid range loss result compared to H’s GS Adv, but once I’d compared the result to my R as std it wasn’t so bad. To the previous graphs for my R I’ll now add the “BP cam and RS/RT duct” curve in yellow. Again, power first, then torque. With 4 curves it’s a bit messy showing air/fuel as well, and that’s just another variation on the same theme anyway.

While still being quite a bit down in the midrange, it’s not as bad as I originally thought. And compared to the “std with short ducts” curve, it’s better above 5,300 and not much worse below that. So when I went back to std cams initially I didn’t notice much midrange improvement as I was running the short ducts. I was quite disappointed with that I must say. Although there was certainly a noticeable top end difference – as you’d expect with 9 less hp. Which left me in a somewhat “huh?” kind of mood.

With the hotter cams, it’s very much an S type of engine. Fairly flat torque curve with power all the way to the rev limiter. In fact, this curve is very similar to my S when it was running the Staintune exhaust and std inlet duct. The cams totally change the character of the engine, and it’s an engine configuration I quite like. Another comment Harold made while riding it was that is less “abrupt” than his GS, and I’d have to agree with that. It’s a bit like the R850R. We had one as a demo/service loan bike, and an R1100RS owner took it while we were working on his bike. I mentioned to him that it was a great bike to ride, with a really nice character about the engine and a noticeable upper RPM rush to make it feel like fun. Also less instant go in the midrange making it easier to ride around than the 1150R. When he returned the 850 he agreed with my opinion. He was quite surprised to be doing so I think, but sometimes that happens.

Having ridden H’s GS after I’ve spent a couple of weeks on mine I think I prefer my R’s engine with the BP cams. Getting away from a standing start may not be quite as quick as a bike with the std cams and pipe (especially at the street drags when they’re running a pro tree and I’m riding). But once it’s revving, the BP cam bike just goes. For me, it just feels much better to use, compared to the std cam bike. It won’t lift the front without prompting, but it will do a nice first-into-second wheelie without much effort once it’s up. Especially across a local 6-way junction I’ve found, where there is obviously just enough crown in the roads to push the front way up as I accelerate across them from the lights. And you get that very cool kind of floating, holding the wheel up with full acceleration wheelie. Whereas with std cams the front comes up much faster and needs to be caught and balanced and into second before the power falls off and the front comes crashing down. Maybe I’m talking up wheelies to the wrong crowd here, but I use the bike for all sorts of riding. Acting like a dickhead being a valid “sort”.

Although H also mentioned that, without that fat midrange his Adventure has, he’d be hard pressed keeping ahead of a riding buddies’ Aprillia RSV-R in the twisties. Unless he changed how he rode it and revved it more anyway.

So, with these results, the next step was to launch a search for the lost midrange. I got to thinking about what could be contributing to the midrange loss that I could change. Most obvious were the air box ducts, so I fitted the std R/GS ducts. The bike felt a bit more responsive in the midrange, but certainly lost some of its top end drive. So I pulled the long ducts (which are two pieces clipped together) and ran the front half. This is about the some length as the RS/RT duct, but smaller in diameter. This helped the top end without really affecting the midrange it seemed, but it wasn’t too definite either way. I then reassembled the long ducts and cut the ends off at the short length and made a nice chamfer for the air to flow in (as previously mentioned), although that didn’t help at all. The next graph shows these results. Red is RS/RT ducts, green long R/GS ducts, blue the front half of the R/GS ducts only, and yellow the cut off and smoothed R/GS ducts. Nothing else is changed.

The torque curves show up some of the changes more. The long duct fills in some of the gaps, but not by very much. Shortening the ducts moves the torque peaks and dips up the RPM range as expected. The smaller diameter front half duct really doesn’t do any better overall compared to the similar length large diameter RS/RT piece, and noticeably cost top end on the road. And giving the shortened R/GS duct a nice smooth entry has, compared to the two steps you get when you just pull the rear half off, sent us backwards. The mid range improvements of the long duct were what made the bike wheelie unexpectedly on me after I first fitted them, but the longer I rode it this way the less I liked it. And learning to wheelie it with the short ducts wasn’t too hard either. To make the graph a little clearer, I’ll delete the cut and rounded std duct curve (yellow), as it’s of no real use.

One thing I did notice was a very clear intake noise the big RS/RT ducts generated. Sort of a cross between a honk and a sharp gurgle, it’s a noise I’ve noticed many times riding various R1100/1150 models without knowing what caused it. Quite odd really.

So the duct variations didn’t make that big a difference with the BP cams fitted. Given the reason for fitting the hotter cams is top end anyway, giving away a big chunk of that new top end in exchange for midrange is sort of missing the point. And a waste of money.

As a side note, if you compare long ducts with std cams and BP cams, you’ll see the difference is lessened quite a bit. The next graph shows the bike (with Staintune system and eprom to suit cams) with std cams and ducts in green and with BP cams and std ducts in red. Showing a bit more clearly the difference in character with the BP cams – less under 5,000 RPM, more over 6,000 RPM.

The final graph is a comparison between the 3 main states of the bike that we considered. Std (green) and the two Duane at Ultimap tuned it for – Staintune system with std cams and ducts (blue) and Staintune system with BP cams with RS/RT ducts (red). Which one you prefer is up to you.

So that’s about it for this report. Whether or not the BP cams will sell for this combo I don’t know. I did like the way the bike rode with them, and after riding it around with std cams for a couple of weeks before I sold it I would probably have gone back to the hotter cams if I was going to keep it. But many buy the GS/R series for the lower RPM power. Depends on what you want I guess.

One thing I was going to play with was the airbox inlet duct, but we never quite got there. Not sure how much difference this would make, given the std duct is pretty good I.D. wise, and the end of it is on the open air. Certainly nothing like the hidden and constricted std R1100S duct.

I was tempted to play more with this bike (I do like it, just like the S before it) – I’d really like to get carried away with a BMW at some stage. Big valves, high comp pistons, that sort of thing. Just to see what I’d get. But I don’t have the ability to tune them anything like I do with Ducati or the other Weber/Marelli bikes, which, more than anything else, really influences things for me. If I can’t finish a job by tuning it properly I won’t start. Which is the opposite of many.

The new 1200 series have bigger valves and higher compression, running more sophisticated management to make it work better in the real world. But it’s pretty easy to mimic, and there are plenty of 100+ hp 1100 and 1150 engines running around. Maybe one day I’ll get there too.

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