Cam Question

[Rob Henderson]

Could someone please give me a very simple layman's explanition of cams. I am doing the conversion in about 3 weeks and I am considering the different options....

SE standard Cams
Andrews N2/N4/N6 (What is the difference)

I am not doing anything out of the ordinary...Just every day driving....I drive the scoot to work most days except when rain of wind is in the forecast. I live in Vegas so rain is not much of a problem...LOL but wind is. Mostly local roads and highway for 20 miles at most at one shot.

2003 XL883C.....

Thanks for your help

[bshadbolt]

I'm not an expert, but this is what I've found from the forum:

The N2's are a very mild grind. A few people here have tried them and not been too impressed.

I have the N4's which are basically the same as the SE bolt-ins. Your choice as to which you buy, performance is the same, price may differ. I have even heard that Andrews make them for HD. I like them - better idle, really no noticable loss of power in the lower/mid rev range, but they come alive at about 4k rpm.

N6's don't know many people running them, no comment.

Cheers,

Brett

[chrishajer]

If you are not increasing the displacement, and are not changing the heads, then you would be wasting your money on any cams at all.

--Chris

[Rob Henderson]

I am not sure what you mean by displacement but I am doing wiseco 9.5 to 1 reverse domed pistons/boring the jugs and SE ignition. I have already done the exhaust and A/C free-flow. I am considering the cams....Do I even need cams? I guess that is my real question.

[chrishajer]

If you are converting to 1200 (that's the displacement part I meant) then you can do cams, but you still won't be able to take full advantage of them with the stock 883 heads. You do not need cams, especially for just a daily driver. Of course, many of us WANT cams, but that's something altogether different.

With the stock 883 heads and a 1200 conversion, I would retain the stock cams.

--Chris

[Rob Henderson]

Thank you.......I will wait until I replace heads...

[lagerdrinker]

just did 1250cc kit with se bolt in cams at same time using stock 883 heads. dont know what the difference is without them but i like the way the bike idles and revs past 3000rpms.

[chrishajer]

lagerdrinker, it would be interesting to see the peak HP with 883 heads vs. more free-flowing heads, when you get them. I imagine the torque will be really good with the 883 heads, but over 5K RPM the torque and HP will drop off (just my prediction.) Unless of course you've already 'cleaned up' the 883 heads a bit.

--Chris

[lagerdrinker]

lagerdrinker, it would be interesting to see the peak HP with 883 heads vs. more free-flowing heads, when you get them. I imagine the torque will be really good with the 883 heads, but over 5K RPM the torque and HP will drop off (just my prediction.) Unless of course you've already 'cleaned up' the 883 heads a bit.

--Chris

i dont notice any drop except fifth gear at about 110 and its still pulling pretty good. have had it to 120 breifly, still only 650 miles on cyls.
gonna do one more oil change in about another 500miles and head for the dyno...being asked for numbers on it. you guys will get them.

[SportyKen]

I did my conversion in stages as the cams were not in stock yet, did the basic conversion with Keith Black pistons, stock heads, man what a difference, low end torque great and top great. Rode for a while until SE bolt ins came, (N4's) holy crap what a difference. I seem to notice a slight less low end but mid and top watch out, Seems to have a much stonger pull thru out the range. Also noticed it idles much better, those are my comments.

[aswracing]

Could someone please give me a very simple layman's explanition of cams.

http://www.nrhsperformance.com/tech_camshafts.shtml

http://www.nrhsperformance.com/tech_xlcaminstall.shtml

[mardyk]

What I've been trying to find out is this: Would I gain anything by putting in N4s or SE cams on a stage one 1200R with no additional headwork?
Do I need to do any headwork?

[chrishajer]

mardyk: what is the goal for your engine? What are you trying to accomplish?

--Chris

[mardyk]

mardyk: what is the goal for your engine? What are you trying to accomplish?

--Chris
A little more top end power without losing any thing in the low end. For now at least. Maybe in the future I'll do full stage2. I realise I might have to increase the revlim as well. Would it be useful?

[chrishajer]

A little more top-end will not happen wthout head work. Cams designed for top-end will probably take a bit away on the bottom end.

The stock heads really don't benefit much from a higher rev limit or cams. I would save my money for now, and do it all at one time.

You would probably see a little more HP on top, but nothing significant without headwork. I don't think it's worth the money.

--Chris

[mardyk]

OK, thanks. I guess, I don't have to worry about this anymore then.

Martin

[chrishajer]

Nope, just ride, and save your money for gas.

--Chris

[mardyk]

You got that right! At 7 bucks a gallon it ain't cheap in this friggin' country.

[hybriDatsun350]

I just noticed that N6's and N8's have identical numbers in the Andrews catalog, but it says the N6's are good for 6,800 and the N8's are only good for 6,500. Just an observation that I thought should be talked about. :)

[aswracing]

N8's close the intake at 44 degrees; N6's close it at 50 degrees. That's a substantial difference in the most critical spec of the grind.

[rottenralph]

So, since I have n8's with 74 h.p. and 79 ft/lbs of torque, what would most likely happen if I switched to the n6. Would h.p. go up and torque go down or what. I am confused. I really need 80/80

[Shu]

If you are going to go with 9.5:1 pistons, then I would opt to stick with the stock cams. The SE .497's (N4's) perform best if you have 10:1 compression or more.

FOR 1200 CONVERSIONS:

10:1 pistons, SE cams, stock 883 heads and stock 883 ignition and you can expect about 71-73 hp and 71- 73 ft lbs. HP will peak at about 5600 to 6000 rpms and torque will peak about 4200 to 4500 rpms depending on how well your head castings are. Put the stock cams back in this engine and it'll loose about 4 or 5 hp, but peak TQ figures will be about the same, just occur about 500 rpms lower in the power band.

9.5:1 pistons, stock cams, stock 883 heads, stock ignition and you can expect about 67 hp and maybe 65 ft lbs of torque. Peak numbers will occur at about 5200 to 5000 for hp and 3800 to 4000 for TQ.

[rottenralph]

SO, how does the close time effect the hp to tq ratio. I assume that is one part and the other is when do you get the happy ending.

[sporty58]

one of the best explinations i have read on close time is located here:

http://www.nrhsperformance.com/tech_camshafts.shtml

keep in mind when talking about "hp to tq ratio" that hp is figured off of torq. hp is (tq*RPM)/5252. A lot of people will argue that one or the other is more important, or more accurate. I tend to look at the HP numbers since it basicly takes into account how often you are making the torque. That is part of the "secret" behind the japanese 600s. by spinning them up to 15k, they only have to make 40ish lbs of torque to get over 100 hp with them.

[hybriDatsun350]

N8's close the intake at 44 degrees; N6's close it at 50 degrees. That's a substantial difference in the most critical spec of the grind.

If you look in the Andrew's catalog that spec is not mentioned. It seems quite odd that they would leave that out. I wonder if they have a reason?! :dunno

[chrishajer]

The do list it online, maybe the print catalog is different.

http://www.chrishajer.com/bike/XLF/andrews.png

Of course, you need to know that's the intake valve closing degrees in the chart there.

--Chris

[hybriDatsun350]

I was reading it like the numbers in the red box are the V8's and the numbers in the blue box are for the V6's. See what I mean?
http://f10.putfile.com/thumb/7/19703192865.jpg (http://putfile.com/pic.php?pic=main/7/19703192865.jpg&s=f10)

I now see that how I was reading it does not make much sense so it is my mistake, but I just wanted to clarify what I was doing wrong.

[chrishajer]

Yeah, it's confusing. The V8 and N8 are the same cam, just for 4 speed (V) or 5 speed (N). So they list the two cams with the year designation, but then use two lines for the Intake and Exhaust valve timing. Agreed, it's confusing. I don't think the table has a key for that either. You just have to know.

But, at least it's there. I think your post will help a lot of people understand it better. Sometimes you look and look at something and still don't see.

--Chris

[Gone]

I have an '06 Xl-883 that will be getting the NRHS 1212 kit and "Special" valve work this winter. I can pick up a set of '06 1200 stock "W" cams - would these be of any benefit to my ride or a waste of time/money?

[Kentucky]

I have an '06 Xl-883 that will be getting the NRHS 1212 kit and "Special" valve work this winter. I can pick up a set of '06 1200 stock "W" cams - would these be of any benefit to my ride or a waste of time/money?

Take the time to talk with the folks at NRHS and let them know exactly what you have in mind. If you're porting the heads and changing the valve dimensions I'm sure they will provide you with a wealth of options based on what you are after as an end result. Know exactly what you are after.....