Andrews cam 21 vs 26

[eaton.mike]

I have just over 500 miles my new 95" with Andrews 26's ... and I too live in So Cal. AP is right... you need to ride aggressively here.  I routinely ride between 80-90mph on the highway, and this set up (along with head work and 9.6:1 compression) runs strong. Yesterday I took the bike up to 120 with no problem... pulled hard all the way. This cam will NOT peter out on you above 4500 rpm.

[wurk_truk]

09 SG here.   In 6th at 70 mph, I cruise at around 2600 rpm.  That's right below where 21s seem to kick some ass.   Works very well.  What REALLY works, is downshift to 5th and one is right on top of the fat part of the 21s and bike runs totally different than stock.    I didn't notice the bike fallin on its face at 4500 either.  Just like 2500 isn't best rpm for cam, neither is 4500.  But, bike runs really decent at both rpm levels. 

In Ohio, anything 20 over (85) can be considered reckless operation and THAT ticket is BIG trouble.  So, for me... 75-80 is tops, and I set the cruise at 72 all the time.

A set of these baby Andrews is THE ticket for totally stock bike, IMHO.  Well... I am happy with mine for sure.

[boooby1744]

I run a 95"/21 combo on an fxd.buddy recommended an s&s 510.he  has seen (and ridden) the light

[grandpa tom]

A lot of discussion about low end torque. Sounds to me like a lot of people never get out of the parking lot.
For those folks that rarely see 4k rpm, how do you keep from getting run over when you merge onto the freeway?
AP

on my 07 FLSTC 4k is:    32, in 1st;  46 in 2nd;  61, in 3rd;  75 in 4th;  90 in 5th;  105 in 6th: and right in the peak tq.

this is my base run dyno, then with stage 1 and andrews 26h I put in red line because dyno's where done a 2 different places.

[attachment removed after 60 days by system]

[grandpa tom]

FWIW, when I called Andrews this winter prior to choosing a cam, they recommended a 26 over a 21 for my 96" touring bike.  Could have just been the opinion of the guy that answered the phone that day though.

+1 on the techs choice on the 96in motor.
Also I am trying to post sheet of just after cam install. to show the red line I put in the above post is real...

[attachment removed after 60 days by system]

[Bagger]

I built my bagger to suit my riding style - long distance rides doing fast 10-14 hour days.  Solo or with the wife and gear great mountain riding bike, winding back country roads and effortlessly cruises the interstate 75-100 mph.  Engine pulls smoothly from 50 mph in 5th gear (no lugging).  Accelerates very quickly and I have pegged the needle several times, the engine doesn't run out of breath.  

With 95 ft lbs TQ at 1700 rpms, throttle response is immediate and smooth. 
No compression releases, no hot start / kickbacks, doesn't detonate, and don't have to retard in summer and lose performance.

http://harleytechtalk.net/htt/index.php?topic=942.0
2002 Road King (Delphi EFI)
Axtell 3.932" Cylinders
JE Flat Top Pistons
Baisley Reworked Stock Heads (84cc)
(9.16:1 Corrected CR)
0.030" Head Gasket
JM20G cam (Intake close 31)
Horsepower Inc 48mm TB
S&S Single Tuned Bored Intake
RB Racing LSR 2-1
3.37 final gear ratio
Dyno Jet PCIII USB

[Bagger]

I have posted this several times, originally posted by AMS back around 2002.

Which cam TW21 or TW26 - the big difference (and the 64 million dollar question) is where you want the peak HP/torque in the rpm range?

For heavier dressers or, uh...  er...uh, heavier riders, or riding two-up or for those of us who just like to chug along and then go like wild without a lot of shifting, a cam like the TW21 is best.  It kicks in at 1800 +/- and pulls thru 5000 with stock heads, and ported heads will get you another 500 or so.  The TW21 has a "right-off-idle" response.  Since it has a little higher lift than the TW26, it can still stretch out thru the high speeds.  Yet, it closes the intake valve early enough to "get on cam" quickly, making it ideal for heavy scooters / big guys/ riding 2-up.  It will have enough torque to pull a freight train, without being so radical that you lose reliability of the long haul.  If you are a "lazy" rider who likes to look at the scenery instead of the road, and does not always shift aggressively, or if you are a big guy or ride two-up, its best to make the max torque /HP in the lower revs...1500 to 3500.  Therefore, you would want a cam that closes the intake valve as close to 30 deg ABDC this will give your engine a broad torque curve - the TW21 does this.  Whereas the TW21 closes its intake valve at 30 deg ABDC, and the 26 closes at 35... the 21 will allow the engine to develop more compression than the 26, especially at low to mid rpms. and more compression = more Mean Piston pressure on the piston = more TQ (at those rpms).  The rpm range for best usable TQ is 1800-4000 with the 21 & 2000-4500 on the 26. They both make the same HP & TQ, but at different rpms/mph and both cams will continue to build power past 5000 rpm).

For normal light rider solo riding, and with light passenger weight, and if you like to shift and stay on the throttle and want a little more giddy-up - then go with the TW26.  With the big bores and ported heads, the bike can use the extra flow the TW26 gives.  It gets "on the cam" about 200 rpm later than the TW21, but lets the engine breath easier at hi-speed touring revs.  Its lower lift with a few degrees more duration is easy on the valve train, runs cooler at high revs and still pulls like a freight train.  The TW26 offers a wide power/torque band, it kicks in strong at 2500 and pulls all the way to 5500.  You do not have to down shift to pass, even at 75, just twist the throttle and zoom on past.

So IMO, either is a good choice for an FL series scooter.  These are mild set ups, but it will put the torque in the rpm range most of us actually use.  Either way, TW21 or TW26 cams have such strong and wide hp/torque curves, especially near the 3000-rpm range that they still cause uncontrollable ear-to-ear-"Potty mouth"-eating-grins.

The TW21 has .008" more lift than the TW26, but .012" less than the TW37. This is less strain on the valve train, makes your motor last longer, yet still adds some more "get up and go".  The TW21's intake valve closes at 30 ABDC, instead of TW26's 35, and TW37's 38.  What this means is the TW21 has 150 crank degrees of piston movement to compress the air/fuel mix, giving a higher dynamic compression ratio (CR) and makes a lot of TQ at low rpms. The TW26 has 145 crank deg for a slightly less dynamic CR, makes a lot of TQ at a slightly higher rpm, but within 200 rpm or so of the 21.  And the TW37 only has 142 crank deg of piston movement to use for compressing the A/F mix, resulting in an even lower dynamic CR, making its best TQ about 500 rpm higher than the TW21. In an "ideal" engine the intake valve would slam shut at BDC. The piston would then compress the air/fuel mixture thru all 180 degrees of crank rotation to TDC. The dynamic CR would equal the calculated CR.  To get power and TQ from the TW37 cam at LOW rpms, you must raise the static CR near or over the threshold of detonation.

If your  riding style is 2000 - 4500 rpm, flower sniffing', touring, passing a truck on a hill at 70, two-up, riding, not hi-rev, tire spinning, solo, tavern to tavern, or red light to red light hot-roddin' then go with the TW21 or TW26.

[MULESKINNER]

07 Street Glide, 26H cams with a simple Cobra tuner. K&N stock replacement A/C and 110" CVO 4" mufflers. Pulls like a freight train compared to stock cams all the way to the rev limiter. NO LOSS of low end torque over the stock cams. Plus,,,I can't get my oil temps to go over 200 degrees with the 26 cams now. 230 to 240 on 100 degree days was the norm before the cam change. I firmly believe the stock negative overlap smog cams on the 07's is the real cause of the heat complaints.

[Bagger]

If money's not an issue, IMHO, a good performance tweak for the TW21 is adding a 1.7 ratio rocker on the intake to increase the lift from .498 to .520 . Stock OEM rockers can be sent to Baisley Performance for the 1.7 roller conversion.  Several vendors sell 1.7 ratio rockers.

Team Latus Harley Davidson
http://www.harley-davidson-forum.net/showthread.php?p=51908

[Eddie Haskell]

 Lot of good information in this thread, sounds like "anything but stock" is the right answer. I myself came here looking for info on the 21H for my 07 FLHT, I have a Arlen Ness AC, Slip-on V&H Ovals and a TMAT (dyno tuned) and it runs great but it's just too damn hot! I was reading through this and kept wondering if someone would mention the heat factor, glad MULESKINNER brought it up, not sure what my oil temps are but when it's hot out I'd bet 250 easy!

[RoadKingRon]

So do you run the stock head gasket with the Andrews 21 or the .030 cometic.....just thinking the .030 may raise the static compression too much or cause detonation. Whats your experience on this?

[Jeffd]

with a .030 my 21's ran very well but would get an occasional hot start kick back.  Not all the time but once and a while.  I was told by Tom at AMS that he recommends the .040 with the 21's.  I ran the 21's with stock hg and with the .030's and could not tell seat of the pants diff.

[RoadKingRon]

I think I am going with the 21's on my 01 RK....they probably will work fine with the MM EFI...also, probably keep the oe pushrods too!

[DavePard]

 This winter I took my stock TC88 '04 Road King installing 95BB SE flat-tops, checked cc volumes 86cc, cleaned-up stock heads, .030 Cometic HG and installed 21N rolloer conversion cams from Herco supplied kit.

  The Low end power was increased right off idle. That was something I didn't suit my riding style because I don't utilize the new found power at those low RPM's. The motor  felt harsh at low engine speed. I enjoy a softer  engine at idle and just above without the added pounding throughout the machine.

Then bought and installed the Andrews 26N cams.  The 26 cams are more to my liking. the engine is softer at low RPM's when just idling around. There is still plenty of low end power for this heavy bike with over 400 lbs on board  and it still has added oomph for getting away from stops and climbing hills without shifting.  The starter works  a little easier too.

Now with the stock 3.15 gearing the increased cylinder pressure is felt and heard at around 60 MPH, but that is the RPM range where I prefer using the greater amount of increased power. For my uses touring mostly mountain roads I'm liking the 26 cams with this combination of parts. The immediate power is increased and continues to build as RPM increases untill I want to shift.

[Wingnut]

Just wondering.  Has anyone tried the 21 with a 2* key to push the whole tq. package up the chart a few rpms, somewhere between the 21 and the 26, keeping the slightly higher lift of the 21?

[boooby1744]

How about a 21 in a 103...................

[HD/Wrench]

the 21 in a 103 would be like the 255 in general terms. As for increasing the rocker arm ratio on the intake with the 26 , just tuned one it did not do anthing better than stock arms. bike ran well made great power no issues.

[Dennis Murawski]

I've got a '07 and spend a lot of time in 6th gear.  I ride mostly one-up, but when I'm heading for a rally I carry a fair amount to camping gear.  Would the 6th gear be a consideration when choosing between the 21 and 26?  Thanks

[HD/Wrench]

I dont think it so much as what gear but more so what RPM range you are riding mainly. The 08 is geared taller than the 09 Sooooo taking that into account i would look to select a cam that is going to build the most tq you can have and in the lowest rpm range. The 21 would work just fine.

[Dennis Murawski]

Are the '07s and '08s geared the same?  Thanks.

[stro1965]

Are the '07s and '08s geared the same?  Thanks.

Yes

[NITROMAN2004]

DAVEPARD,can you please elaborate what you mean by the motor felt harsh with the 21.

[harleytoprock]

I think I know what he's feeling. The bike kinda idles with a heavy pounding feeling. Your feeling like each cylinder is hitting real hard. It mellows out as the rpm goes up and your moving faster. Lets see what he says.

[Hawg Holler]

DAVEPARD,can you please elaborate what you mean by the motor felt harsh with the 21.

I installed the 21s in my Road King many miles ago. The idle is a little rougher than stock due to the increased cranking pressure the 21s develop. But the better low end performance is worth it. I actually like the idle. Has a nice lope to it. The exhaust note will also change slightly with a little more punch to it. As harleytoprock says, it smooths out as rpms increase.

[DavePard]

In response to Nitroman2004. What harleytoprock  said a couple of posts back.
"The bike kinda idles with a heavy pounding feeling. Your feeling like each cylinder is hitting real hard. It mellows out as the rpm goes up and your moving faster."

The 26's are quieter and smoother, at least below 2,000 RPM, than the 21's. Neither of these cams seem to lope much, to my ear.

  I have about 2,500 miles on the 26's now. I took out the 21's after 350 miles and installed the 26's because when going slow I don't want that level of  pounding. How to quantify that? I'm open to suggestions.

So where do you want the power to be and how smooth do you like it and where? Choose for yourself.

  With the parts I chose (shown a few posts back), compared to stock 88, the 26 has an increase in power just above idle (probably at idle too) and more above 2,000 RPM. When tuning I've taken off in second gear easily, though accidentally. Very-very rarely do I use all the power the engine is capable of making below 2,000 RPM and I like the power to build at about the rate of the 26's. The 21's do seem to have more compression braking though.

  I chose the cam that suits me... only took two tries. Iam trying to describe what I have found with one combination of parts.  I'm trying just to inform, not to tell anybody what they want for themselves. Then I hope that you enjoy your motor.