I have had n8's(490 lift long duration) in my bike for 9 years or so and I am wondering if they are the right cam for me. I just dyno tuned my bike and I was a little dissappointed with 74 h.p. and 79 ft/lbs of torque. I have it in my mind that I need 80 h.p. So, the question is, is there a cam that will get me there. I have ported 883 heads with a dyna ignition, s&s super e with 3" k&n and desperado teardrop cover, 1200 with .030 over pistons. Is there a cam that will get me the numbers I seek or is the torque the number that really matters. I don't suppose I will ride around at 6000 all day long.

I have had n8's(490 lift long duration) in my bike for 9 years or so and I am wondering if they are the right cam for me. I just dyno tuned my bike and I was a little dissappointed with 74 h.p. and 79 ft/lbs of torque. I have it in my mind that I need 80 h.p. So, the question is, is there a cam that will get me there. I have ported 883 heads with a dyna ignition, s&s super e with 3" k&n and desperado teardrop cover, 1200 with .030 over pistons. Is there a cam that will get me the numbers I seek or is the torque the number that really matters. I don't suppose I will ride around at 6000 all day long.

I'm doing some work this winter, and I'm wondering the same thing..

What's the best cam for between 2500 and 5000? With a high-compression 1200 about to get headwork and valve work/ 1200 valves...

Not to hijack, but how DO you choose the best cam?!?!?

The Andrews "8" cams are a pretty nice street grind. I'm sure there are a few other good choices though.
Those ported 883 heads still have stock size valves? If so, your numbers actually look pretty good. IMO, more cam might hurt your numbers without better flowing heads.
Picking cams is probably the toughest chore there is. Lots of good cams out there. And they are all a bit different from all the others.
Ted

http://www.nrhsperformance.com/images/drmikemccambridge.gif

Here is the dyno sheet from the new miracle conversion with flat top pistons and 536 cams. Almost 80 ft-lbs. at 5000.

That is the range where my torque is peaking. I am not sure if I should be happy with the torque where it is and stop screwing with the rest. Mine are 883 heads that I ported and cleaned up the compression chamber. I only understood what unshrouding the valves means when I was done. I used triple valve springs and rowe valves. I have my 1200 heads here and I will start working on them and return them to service in the winter.

There are a lot of different cams out there that would get you to the 80hp mark if it is the cams holding you back. The problem of finding the right one isn't so much a matter of just getting a cam, but getting a cam that works with the rest of the package(exhaust system, compression ratio, combustion chamber, porting etc). Probably the best way to insure things work together is to get the pipe, cams and headwork as a package, or at least decide on the package you are working towards before you buy any one part. The knowledge of what works well together is where the top quality shops are really worth the money.

I have never used them but looking at the numbers, I would expect the n8s to make their power lower down in the rev range. They do have a fair amount of duration but they close the intake pretty early. as a general rule of thumb, if the intake closes in the lower 40s it is more of a torque cam. high 40s and low 50s is more of a mid range to high end cam and get above the high 50s it should be a top end cam.

The NRHS home page tech section has a good writeup about cam selection.

On a final note, I would be a bit cautious about about hunting for a dyno number. A dyno is a lot like a hammer and chisel in the right hands, you get a sculpture in other hands you get busted rocks.

hey sporty 58, what kind of numbers does your bike pull with those hi-lift cams and stage 2 heads.

I was looking into some N8's, but now you've got me worried!!! I don't know what to get now, haha. :dunno

I'm using V-8 cams in my motor. I also used them when I was into serious dragracing. They are not monster hp number cams, but they are pretty respectable. I made 101 hp with them in the 74" motor, but it was not set up for street. With the 84" motor, I'm probably making very near 115 hp. The power comes on very early. Putting along in first just doing enough speed to keep upright, if I blip the throttle a little, it will lift the front wheel. That's without using clutch. I kind of like the under .500 lift because it is real easy to set heads up for them and it is pretty easy on the valve train.
I do think that 883 size valves are not the right chioce for the 8 cams though.
1200 size valves and a bit more compression wakes up the 8 cams.
Ted

hey ralph, it sounds like u could use a set of stage 2 '04 1200 heads, i bet u'd gain 15hp with them, and at least 5tq... u have the perfect cam for them...

hey sporty 58, what kind of numbers does your bike pull with those hi-lift cams and stage 2 heads.

I don't know for sure. I am stationed in korea and haven't been able to find a good or even a fair dyno operator over here. The auto craft shop does have a older superflow dyno sitting in there that i played around with before i put these cams in. I was able to pretty consistantly get into the low 80s with the 551 cams which is about where i would expect it to be. (the numbers tend to run lower on a superflow.)

I was going to try it with these cams last friday but some stuff came up at work so i will try to catch the next decient day and do some rough runs myself. I expect the numbers to be somewhat in the ballpark of the .585s the cam specs are simular.

Seat of the pants though, I gave up a little bit down low switching from the .551s but gained a LOT above 4k. It is really nice as long as you are above 3K. there is a rough spot between 2k and 3k (estimated) that i haven't been able to get rid of though and i don't really expect to with these pipes.

Help!

hehe

I have 10:1 compression SE 1200 pistons and stock 883 heads on my '05 XLC and i'm looking for more torque in the mid range and after all this reading i've got as conclusion to do a package doing a flowing job on my heads and getting new set of cams, wich so far i believe should be the 8's.

But i didn't see any comments on the 4's. Wich one should work best for my needings? I still got a pair 2" drag pipes (ok, wrong exhaust system but thats what we can afford in Brazil :frownone ), rejetted carb and freer AC.

Can someone help me? Thanks a lot!

Oh, yeah...75 rwhp is ok for me, i'm looking for that punch when open the throtlle like from 60mph - 100mph in no blink of eyes :roflblack

Tks folks!

I have the V4 cams in my 1200 conversion. But I opted to get the SE 1200 heads that NRHS had on the shelf, put them up for sale to get rid on them. Dan told me that the V4 cams will love the larger 1200 valve as opposed to an 883 valve ( I was going to go with stage 1 883 heads, using stock 883 valves). Dan says the SE heads flow about the same as a stage 1 883 head, but have the advantage with the larger valves.
You may want a stage 2 head with bigger valves, and I'm sure you'll gain about 15hp. Get yourself a pair of XB heads, and you'll probably see an improvement out of the box with no porting.

Thanks Engine, but...can i have differente heads with my 10:1 SE pistons? Because i heard they are designed to work with stock 883 heads and so i couldn't have any other kinda head.

Tks a lot.

Thanks Engine, but...can i have differente heads with my 10:1 SE pistons? Because i heard they are designed to work with stock 883 heads and so i couldn't have any other kinda head.

Tks a lot.
Yes, conversion pistons are dished in order to yeild a 10:1 compression ratio with a small 883-head combustion chamber (49cc). The 1200 chamber is larger and hemispherical (67cc). To use a 1200 head, you'd have to have flat-top pistons (no dish). My compression is 10.5:1 because NRHS gave me a specific piston with a 10* dome to work with the combustion chamber of these heads.

If you are using 883 heads with dished pistons, and want more flow, the best bet would be to have them Stage 2 ported with larger valves installed. This way you don't have to change pistons. Of course porting takes time, and to cut the down time on the bike considerably, you can buy a set of 883 take offs from ebay or swap meet or wherever, have those ported out by NRHS. Then you can swap them with your stockers in one day. Sell your stockers on ebay to get some money back.

see Aaron's (NRHS) write up on sportster heads. He says that in stock form, 883 heads are among the worst, but respond very well to a good porting and bowl blend/valve job.

http://www.xlforum.net/vbportal/forums/showthread.php?t=14000

Tks a lot Engine, it happens that i live in Brazil and my options are very restrict. Every single part must be imported from the US and this takes time and lots of cash.

Anyway, i'll try this stage 2 tip. Can you help me finding an article or so teaching me what stage 2 means? Sorry for taking your time dude, i'm kinda new into HD's engines.

Tks a lot for everything so far! :D

Tks a lot Engine, it happens that i live in Brazil and my options are very restrict. Every single part must be imported from the US and this takes time and lots of cash.

Anyway, i'll try this stage 2 tip. Can you help me finding an article or so teaching me what stage 2 means? Sorry for taking your time dude, i'm kinda new into HD's engines.

Tks a lot for everything so far! :D
NRHS web page has a onverview of the headwork they perform:

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

Tks once again

.
Anyway, i'll try this stage 2 tip. Can you help me finding an article or so teaching me what stage 2 means? Sorry for taking your time dude, i'm kinda new into HD's engines.
:D
_________________________

www.sportster.org

has lots of info and links.
Click on "tech" at the top of the page and it'll lead you to answers for your many questions.

Good luck.

:tour very useful info there! Tks.

Peak torque. Peak hp. These should be used as guides and only as guides. What is really sought is the best "combined average" figures in the desired rpm ranges. May be easier on a racetrack where you know you come out of the slowest revving turn at 4,700 rpm and let it rip to 7,200 rpm - that's a fairly consistent number. On the street, you could be loafing along the beach in fourth at 1,800 rpm one moment and want some quick throttle, or a mile down the road be spinning it at 3,500 in third, getting ready for a quick pass. An engine built to provide the top "combined" average hp and torque in the rpm range where you spend 80% of your riding time, will NOT be disappointing. But, if you only rev to 6,500 rpm at rare times and shoot for big numbers, while your 80% is between 2,000 rpm and 4,500 rpm, disappointment is certain. To me, the big pay-off on the dyno charts is being able to compare LOTS of them for those best combined averages you seek.