| Author | Message | ||
     Tom_b  |
want to upgrade my x-1. Like the looks of the Andrews N9 Cams on paper.anbody know about these in the real world. Was kinda thinking of N8, but don't look too impressive on paper, doesn't look like much of an upgrade over the stock cam. also how will the N9 work with my fuel injection and race ECM. X-1 has about 10,000 miles on it. | ||
| Aaron |
The N9 is not a bolt-in, and it's not an easy set of cams to install. You'll need better springs, shorter guides, probably a little valve sinking at Thunderstorm valve sizes (1.810/1.575), and possibly some opening up and/or deepening of your piston's valve pockets. They're not as bad as some cams for installation (i.e. N83's, N87's, etc), but they definitely need a little attention. One good thing though is they have a smaller base circle. Chances are you'll be okay in the cam box as far as lobe swing clearance and tappet anti-rotation pin clearance. As far as how they run, with all that overlap (which causes the installation hassles in the form of tdc lifts) they tend to be real sensitive to the exhaust system. But set up right, you can definitely make some power with them. Red Shift 585's are a much easier to install alternative, although they're a little taller and use the stock base circle so they'll demand some cam box work. SE .536's are another popular grind in this size range. Not nearly as bad to install, although the exhaust valve closes pretty late (.236 tdc lift) so you've gotta watch the exhaust valve to piston clearance. You probably won't have a valve to valve issue at stock sizes, but if you step up to 1.850/1.615 valves or bigger you need to check it and you may end up sinking some valves. When we do a set of heads with 1.900 intakes that are going into a .536 cam, we generally end up sinking the exhaust valve .050 or so, sometimes we drop the intake a little too. The new SE .551 lift cam set is another grind you might look at, it's taller and narrower, low tdc lifts which makes'em easier to install. Going with more lift probably won't help you much with stock heads. Every stock head I've ever seen was done by the time it hit .500 lift, opening the valve more doesn't increase flow. | ||
| Tom_b |
Hey Aaron, I was hoping you would be one to respond I've seen some of your posts and you seem pretty educated about hi-po Buells. for a better and easier install would the N8 cams be the better choice, and would they offer a noticeable improvement over the stock X-1 cam which are similar to the N4. during the upgrade I was going with at least the Nallin stage 1 head rebuild.How well would these changes work with the X-1 injection | ||
| Aaron |
Tom ... you're welcome and thank you ... the two grinds you mention, N4 & N8, are pretty close together. The intake lobe is the same, albeit advanced a couple degrees on the N8, which ain't a lot. The main difference is the exhaust lobe, the N8's is broader, both opening 4 degrees earlier and closing 4 degrees later than the N4's, making it a "dual-pattern" grind (more exhaust duration than intake duration). Opening an exhaust valve earlier uses more of the combustion pressure to overcome the pumping losses and push the exhaust out. That can be helpful especially at high rpm where you have less time to get it done. Opening earlier also shifts the pressure wave timing in the exhaust system which can move the powerband up slightly because the wave will be timed to arrive at the chamber during overlap at a little higher rpm. Closing the exhaust valve later gives more overlap, i.e. more time with the exhaust system connected to the intake tract at the beginning of the intake cycle, and therefore more opportunity for the exhaust to affect the intake flow. First thing I always look at in a cam grind though is the intake close point, it has more effect on the powerband of the cams than any other spec. It's the point where you seal the chamber as the piston is coming up on the compression stroke. Earlier allows the motor to build more compression for a given compression ratio, but gives up cylinder fill at higher rpm because you slam the valve closed while the inertia of the incoming charge is still filling the cylinder. Later lets you use the fuel's inertia to fill the cylinder at high rpm, but can push back a portion of the charge at lower rpm. In general, earlier = lower rpm & works with lower compression ratio, later = higher rpm & needs higher compression ratio. The intake close point of these two grinds, 44 & 46 degrees, is what I'd call a moderate performance number. By comparison, the SE 536's are at 50 degrees, the N9's at 53 degrees, and the 585's at 59 degrees (which is why I can get away with 11:1 in my M2). So in a nutshell, personally I wouldn't expect a miracle by swapping out your N4's for the N8's. To the degree your motor is being constrained by exhaust system pumping losses you'll see an improvement, but I kinda doubt that's what's holding your motor back. I could be wrong though. In the bolt-in world, the N4/Stock X1/SE bolt-in is a pretty good grind IMO. The good news is that at Stage 1, we now include our bronze manganese guides, which allow for plenty of retainer to guide clearance and hence more lift. Hey, we gotta knock the guides out to cnc the heads anyway, we might as well put a good one back in. The bad news is that you may get into trouble on your springs, with the pressure and/or travel. We may be able to shim'em up to get more pressure, but you may run out of coil bind clearance if we do. But we'd be happy to put you into a set of premium springs & locks & retainers, & even high flow stainless valves if you want. Now you know why stage 2 is so popular  . Best of luck with your project and let me know if I can help. |
