Then once completed, contact Ed, at The Dyno Difference, located in the DFW area.
He'll ace the tune for you.
Scott

 

AMS is in the Fort Worht area; it that's your shop, you are in good hands. Forget the SE251. There is a difference of opinion on what a "manageable" corrected CR and CCR is for a street build. I like 9.3 and 190psi but some are OK with 9.6 and 200. With the 204, you fall in the latter bracket.

I live in San Antonio so, being from Fort Worth, you know how hot it gets in Texas in the summer; particularly south Texas. I have run the SE204 in several different configurations and I really like the cam. However, my expereince has been that with the 8* ground in advance on the intake and exhaust, it is compression sensitive, can be challenging to tune and tends to ping in Texas summers on reformulated fuel. So if, as Scott suggests, Ed at the Dyno Difference is up to the challenge, the 204s might work out for you; however, I would talk to Ed befor pulling the trigger.

My view is why take the chance just because you have a set of cams on the shelf? You can sell the cams you have and more than cover the cost of new cams; they aren't of much value sitting on the shelf collecting dust. There are several you could choose from but the Andrews TW37 would play well with the rest of your build. Very similar profile as the 204, 4* later intake close, easier to tune and 100+ torque and mid 90s HP guaranteed with a good tune.

As usual, JMHO.

 

Yes, AMS is the shop I am going to use. They are doing the pistons and bore. Heads are already done. I have heard good things about the Andrews TW37. One other question. I have the Thundermax with Auto Tune in the closed loop config and have never needed a Dyno Tune. How well would this handle the SE204 8* advance. That's an $800 box under my seat and would like to continue to get my investment out of it, lol. I am settled on everything and down to this last question on between the SE 204 and the Andrews TW37. Thanks, Tim

 

I can't answer the TMax question WRT the 204; just don't have any first hand knowledge or experience. However, with 200+psi cranking compression, some tuners find the 204s challenging, not so much with AFR but with timing. From what little I know about the TMax auto tune feature, it does on auto tune timing; you would have to do that your self or put it on a dyno and let a tuner have a go.

As for the 204 vs the 37; in your application the 37 would be my choice because of the compression issue and the fact that the 37 is such a good all around cam.

 

Instead of buying another set of cams, you could install the 204s retarded 4* and achieve essentially the same valve timing as the 37s.

200 psi isn't too high for the street, lots of 103/255 builds running around with that kind of cranking pressure. Better to have a dyno tune, though, if you're going to be cranking that much pressure.

 

Shaving the pistons and then using a .045 stock head gasket gets me close to dead nuts on with the SE204 cam doesn't it. I still would like to know if anyone thinks the Zippers Thundermax with Autotune in closed loop will support the cam.

.045
9.87:1 Static Compression
9.29:1 Corrected Compression
193 Cold Cranking Compression

.040
9.97:1 Static Compression
9.39:1 Corrected Compression
195 Cold Cranking Compression

.030
10.18:1 Static Compression
9.58:1 Corrected Compression
201 Cold Cranking Compression

 

Running a thinner head gasket will reduce detonation problems, even if it slightly raises compression. I'd go ahead and set the squish at .035.

I'd think you'll get better performance if you keep the compression up, and run the 251s or 211s, but if you're sure you'd prefer the 204s, then getting your cranking pressure under 200 is a good idea. I have them in my bike at about 190 psi, with no detonation problems at all, but I don't have the hot Texas summer days to deall with, either.

I'm with dj, I don't have any first-hand experience with the Tmax unit, but it's not going to hurt to give it a shot. I use the PCV with autotune, but I had to pull out a little timing in the higher throttle settings to keep detonation at bay.

 

If you want a Specicic cam profile, run the cam, don't try to replicate by advancing or retarding or using hilift rockers. I know guys do i but I am not a fan; run the cam for your profille.

I am not too concerned with 200psi cranking but corrected CR above 9.3 is tops for me for the street, particularly for a touring bike.

You Will be fine with a .040" head gasket. The Tmax auto tune feature does not adjust timing. You will need dyne time and a tuner familiar with the Tmax to get timing right with either cam. Given your circumstances, I like the 37; I would not run the 251 or the 211; give up too much on the bottom end. As always JMHO.

 

I agree with this, but if you've already got a camset that's within a couple of degrees of the ones you want to run, it's cleaper to just advance or retard the set you've got than buy yet another set of cams.


There's nothing sacred about a cam profile. Lots of cams are similar within a couple of degrees. We do all kinds of things to try to get the motors dialed in. I can't tell you how many times folks get advised to advance a set of cams by 4* to try to adjust the torque curve, usually in an attempt to push it to the left a bit. Some cams will benefit from this, many times there's not much difference at all, but it usually doesn't hurt much of anything. The 204 cams are already advanced 8*, and I wouldn't recommend advancing them any further (despite what Joe Minton has written), but retarding them 2 or 4 degrees is not going to cause any problems.

Running high lift rockers instead of stockers is an old hot rod trick, it can do many things, including speed up the ramps, and is often good for an addditional 2 or 3 hp and ft lbs. Sounds like not much return, but 2 or 3 here and there add up pretty fast. You get a little more lift, without increasing lifter and pushrod travel, or increasing the pushrod to rocker arm angles.

 

B'dude,
I don't disagree, in principle with anythign you said; I am just not a fan of trying to achieve a certain cam profile advancing, retarding or changing rocker ratio. Advancing or retarding cams is done to move the intake close event but, as you know, every other valve timing event is also advanced or retarded and the valve relationship to TDC is changed. Add to the stew a rocker arm that increases TDC lift combined with heads that have been decked and, sometimes, bad juju happens. I just prefer selecting a cam and building around the cam.

The OP is about to spend, or has spent, $1500 or thereabouts and has a set of heads that have been decked .050". I am sympathetic to saving a few $$ here and there but, in this case, I think he would be better off selling all three of the H-D cam sets which will net him more than enough to buy a new cam set and have some left to put toward a dyno tune.

If, for whatever reason, the OP wants to run the SE204, running with a .030" head gasket with 9.6 corrected and 200+ CCR is asking for trouble. Running it with a .045" head gasket may not be so bad but I would be concerned about detonation with 193 CCR. I think he could run it with a .,040" head gasket and be fine as long as he understands that a dyno tune and premimum fuel are absolutes.

If I was in the OPs shoes, I would sell the H-D cams and pick up a set of TW37s. Cometic makes a .036" head gasket for the 3.875" bore but the head gasket ID is 3.910" which should work with the 3.905" bore better than a 4" head gasket. Shave the pistons down to a -1.5 or -2.0 dome, break it in and get it on a dyno. JMHO.

Edit:
Another consideration; the OP should have AMS estimate the piston dome volume if completely removed, i.e., "flat topped". The last set of CP pistons I used in an all bore 104" build cam with a 6cc dome. When completely removed, the dome volume was -2.5. Just because a piston is flat topped doesn't mean the dome volume is -1.5 per most of the calculators floating around.