Se255 Or Tw21 : V-Twin Forum: Harley Davidson Forums

Jeff McKinney · 09-24-2009, 10:39 PM

Which cam will come on sooner?,don't care if it's all over at 4-5k rpm.I am only concerned w/torque in the basement,sooner the better!

99% 2 up on an 07 electra glide.Thanks!

Gump 159 · 09-24-2009, 11:32 PM

I used a site called "nightrider.com" to get the low down on cams .

They have a complete list of all cams and specs from degrees to overlap. Some folks will say that it has some errors but it is a good starting point. It will tell you the range and RPMs the cam start to develop HP. Also the people have a quick turn around on e Mail questions and are very helpful and know their ****. Just throwin in my 2 cents...

arealinvestor · 09-25-2009, 05:57 AM

Quote:

Originally Posted by Jeff McKinney

Which cam will come on sooner?,don't care if it's all over at 4-5k rpm.I am only concerned w/torque in the basement,sooner the better!

99% 2 up on an 07 electra glide.Thanks!

The SE 255 will come on sooner!! The bike should be dyno tuned though to help with the heat generated by the 255!!

HerkoBagger · 09-25-2009, 07:31 AM

Quote:

Originally Posted by arealinvestor

The SE 255 will come on sooner!! The bike should be dyno tuned though to help with the heat generated by the 255!!

Would a 255 generate more heat than a 21?
If so how does it generate more heat?

arealinvestor · 09-25-2009, 10:12 AM

Quote:

Originally Posted by HerkoBagger

Would a 255 generate more heat than a 21?
If so how does it generate more heat?

The cam has a earlier intake close which makes for more CCP,more cylinder pressure & a higher running comp!!!

A-one · 09-25-2009, 11:33 AM

The SE 255 has more lift than your stock cam, but can still cause some heat issues. If you are looking for more pulling power, change your gear ratio on any 2007-2008 bike, especially the baggers - you won't be disappointed. Shorten up the gear ratio a bit and either the 255 or 21, and you'll have plenty of low end power. The 21 cam will most likely run cooler.

route66paul · 09-25-2009, 02:43 PM

You really want a cam grind that has more overlap. These new legal grinds have very little or no overlap to reduce polution, the problem is they have to burn too hot to burn it all off. This is not the best recipe for power or a long lasting motor.

HerkoBagger · 09-25-2009, 03:05 PM

Quote:

Originally Posted by route66paul

You really want a cam grind that has more overlap. These new legal grinds have very little or no overlap to reduce polution, the problem is they have to burn too hot to burn it all off. This is not the best recipe for power or a long lasting motor.

The overlap of the 255 makes heat and shortens the life of the engine?
What kind of overlap do the stock cams have?

sloxl · 09-26-2009, 06:20 AM

Since 2005(?) the stock cams have no overlap. In fact it is a slightly negative number ( I forget exactly how much).

dirtrace95 · 09-27-2009, 03:50 PM

Put a set of 26's in there,thats better than both the choices your looking at,
give it some duration and overlap so the poor thing can breath some.

Jeff McKinney · 09-27-2009, 11:44 PM

Quote:

Originally Posted by dirtrace95

Put a set of 26's in there,thats better than both the choices your looking at,
give it some duration and overlap so the poor thing can breath some.

So you are saying that the 26 will work better than a 21 or 255 from 1500-4000 rpm?

bigbluff · 10-10-2009, 04:30 PM

The Andrews TW21 is not a "new" grind. It's been around for quite a while.

The question is which cam does the best work in the RPM you ride in. The SE255 comes on the earliest and gives out the earliest. The TW21 comes on a few hundred RPM later and gives out a little later too. The TW26 comes on a few hundred RPM after that and gives out a little later too. The 255 has the least overlap of the group... as you increase the overlap (intake valve closing later) you increase the RPM at which the cam does its best work. You are also robbing torque from the lower RPM as you do this...and making the engine less efficient at these lower RPM. The way to get some torque back at the lower RPM with higher overlap cams than these is to increase the compression of the engine...which is expensive and starts generating the heat again that these guys are complaining about.

Personally, I wouldn't worry so much about the heat issues...just make sure your engine is tuned properly for the cam you are running. And select the cam you want based upon what RPM you need it to do its best work.

Me? I am like you... I couldn't care less what happens above 4500 RPM. I have a bigbore kit (103) and the SE255 cam. In my '03 I had a bigbore (95) and TW21 cam. They were wonderful and pulled every bit as hard in the RPM I rode as those who were running "stronger" cams with a lot more money in their builds. Certainly if they wound out their engines they pulled harder.

Oh... and the guy who mentioned about changing the gearing... absolutely... gearing will have quite an effect on the torque you feel in your butt. So a simple way to increase torque is to just down shift a gear.

nosillyname · 10-16-2009, 08:19 AM

Quote:

Originally Posted by bigbluff

The Andrews TW21 is not a "new" grind. It's been around for quite a while.

The question is which cam does the best work in the RPM you ride in. The SE255 comes on the earliest and gives out the earliest. The TW21 comes on a few hundred RPM later and gives out a little later too. The TW26 comes on a few hundred RPM after that and gives out a little later too. The 255 has the least overlap of the group... as you increase the overlap (intake valve closing later) you increase the RPM at which the cam does its best work. You are also robbing torque from the lower RPM as you do this...and making the engine less efficient at these lower RPM. The way to get some torque back at the lower RPM with higher overlap cams than these is to increase the compression of the engine...which is expensive and starts generating the heat again that these guys are complaining about.

Personally, I wouldn't worry so much about the heat issues...just make sure your engine is tuned properly for the cam you are running. And select the cam you want based upon what RPM you need it to do its best work.

Me? I am like you... I couldn't care less what happens above 4500 RPM. I have a bigbore kit (103) and the SE255 cam. In my '03 I had a bigbore (95) and TW21 cam. They were wonderful and pulled every bit as hard in the RPM I rode as those who were running "stronger" cams with a lot more money in their builds. Certainly if they wound out their engines they pulled harder.

Oh... and the guy who mentioned about changing the gearing... absolutely... gearing will have quite an effect on the torque you feel in your butt. So a simple way to increase torque is to just down shift a gear.

Thanks, thats very useful info. From what you have said regarding those three cams, it seems that the 21 is the "middle of the road" and IMO possibly the better choice - a compromise between the SE255 bottom end style and the 26 mid range cam that likes slight compression increase...... have I got that right?

sloxl · 10-16-2009, 10:56 AM

I see the OP also rides a 2002 Suzuki, hope you tear into the right engine!

nosillyname, you are right although the 26 is at the low end of mid range and does not have to have a compression increase to work. If you do decide to use the 26 and want to increase the compression you don't have to go to the expense of shaving the heads, just go to a thinner head gasket like the cometic .030. That is a good quality gasket and will give you a cheap, albeit small, bump in compression. If, after doing your research, you do decide to go with cams, headwork, big bore etc., make it a package deal. They should all be matched up or you are just pouring money down the drain.

nosillyname · 10-16-2009, 08:34 PM

Quote:

Originally Posted by sloxl

I see the OP also rides a 2002 Suzuki, hope you tear into the right engine!

nosillyname, you are right although the 26 is at the low end of mid range and does not have to have a compression increase to work. If you do decide to use the 26 and want to increase the compression you don't have to go to the expense of shaving the heads, just go to a thinner head gasket like the cometic .030. That is a good quality gasket and will give you a cheap, albeit small, bump in compression. If, after doing your research, you do decide to go with cams, headwork, big bore etc., make it a package deal. They should all be matched up or you are just pouring money down the drain.

Thanks, yes I agree the 26 with a .030" cometic head gasket would be a great combination.......... but if I can get the same result with the 21 cam with the stock head gasket it would be a much better cost effective move not having gto pull the heads. But I'm still not sure of the results of the 21 because it doesn't seem as popular?? Not sure why?