Well, Phil hasnt chimmed in yet but I will. I would agree with what he says on his site.
And this is the basis on HQs succesful engine kits. The ports on my heads are not much larger in volume over stock heads, just cleaned up with a proper valve job.

The HD engine is not a high reving engine and slow(over sized)ports definently make for a sluggish V-twin. and just about any engine for that matter.

I dont think this secret was too well keepted Ive know about this for over a decade myself, but I think many just refuse to belive it! You only need a port volume large enough to feed the engine and nothing more, but this step is quite elusive! you cant find it on a flow bench in most cases, but you will see it on a race track near you!
you can try to calculate it with math, but offten its determined only after its applied in a real world situation.

 

i think it honestly comes down to what you ride and how you ride it. you ride a bigger heavier bike you are gonna want a package that makes high torque numbers ie. a quicker more efficient head velocity at lower rpm/engine speeds. you ride a lighter bike and you don't need all the torque to get you going you might want a higher rpm setup where low rpm/port velocity is not really needed. my dyna with my 110, i'm not too worried about low speed torque since my bike weighs 3 lbs (not really but you get the picture) and i don't mind riding the limiter to get my motor to make power. imho you can't beat a set of screamin eagle heads if you get them at a good price, and then ported and cleaned up on top of that, you just can't go wrong. if you make enough horse power you will have plenty of torque to floow and you just have to gear accordingly after that. my .02 only.

 

Hey Kirk....

Sorry for the slow response... i've been out riding the last couple day. The weather is getting really nice!

I would certainly not dispute theinfo on that website. In fact, I agree with most of it. I have whitnessed multilpe examples the good and bad results he refers to. It is certainly not anything he "invented", it just that he "figured it out too".

FWIW... One of the things I have "figured out" is that left to my own judgement I have a 50/50 chance (at best) of coming up with a great solution or combo. When I finally accepted that painful reality, it enabled me to search for someone that really had the answers to this V-Twin power game. Having done that, the real challenge was to simple LISTEN and FOLLOW the recommendations and advise provided. Doing those things has dramatically my increased my ability to achieve excellent results on a repeatable basis.

There is no single source "be all, end all" for this stuff.... Just find someone you TRUST, and let them guide you.

 

From a performance per dollar value standpoint, you only need to look at the dyno charts in the SE 2008 Pro Racing Parts Catalog. You can download it here:

http://www.harley-davidson.com/wcm/C...p?locale=en_US

I have the paper version of the catalog and at pages 24 and 25 it shows many of the SE "package" builds with dyno charts for them. While they are clearly better than the stock engine configurations, the torque and hp just aren't nearly as good as the quality aftermarket packages available IMO.

Given the "peaky" character of the torque lines in the SE dyno charts, it can be very misleading as to how strongthe engines perform if you look only at the peak numbers--the peak numbers may not look bad, but because of the mountain-like peaks, they don't run asstrong as bikes using aftermarket packages that have much flatter torque lines.

Presumably, Harley-Davidson knows how to put a motor together using their various heads, cams, pistons, etc., and they could be expected to promote and advertise their "best" efforts and results. For me, at least, I am not impressed.

If you have an SE build and are happy with it, that's great--performance is an individual choice and there are many happy owners of SE builds.

 

I thought it made sense. Bernoulli's principle and all that good science about flow and pressure. For myself I've already made up my mind to go with HQ when the time rolls around, but it'll be a little bit.
I think Harleypingman rolls up the question nicely though regarding the performance of the the SE kits.
What a great place the forum is!

 

it was too late for me.... i had my engine build done before i spoke with doc...i am waiting to see if the performance i get from my build is sufficient...if not then i need to save up some cashola and have doc work me a sweet build.

 

So what is everyones opinion on the breakin philosophy? Would you guys ignore the conventional wisdom and go ***** to the wall? My new Softail will be here any day and I'd like to hear opinions on how some of you would approach the breakin after spending 20+ G's.
So much info, so confused. Thanks in advance.

 

Blanket statements is where we all getinto trouble, in my opinion. All SE heads suck??? Not so. It is, as some have said, a matter of a COMBINATION of matched components and realizing limitations. MoCo parts are mass produced and are designed, for the most part, for a broad spectrum of users.
Another point to remember is that NOBODY has the money or has spent the money that the MoCo has for R&D.
I have a set of the older SE Performance heads, not sure why they don't make them anymore, and am completely happy with my results. But I did realize the limitations of these heads and had them ported slightly, and polished up to clean up the production line castings. The smaller exhaust valves in this design do a great job of increasing exhaust velocity.
Could I get more power out of this motor with aftermarket stuff, probably if I changed the whole combination. Remember its the combination!
Ever notice that when the aftermarket guys offer to help, they always have you chage to their heads, their cams, their intakes etc.. BECAUSE THEY KNOW THE LAW OF COMBINATIONS.

 

My experience with SE heads is that out of the box they don't flow as well as they should but with a little work they flow very good. Nobody wants to buy a set of heads & have to send them out to be worked but that's what you have to do with the SE heads. The older ones had 1.90 intake valves & I seen somebody mention 2" valves. The SE Pro ACR has the bigger valves with the CVO combustion chamber. The SE Pro MCR has the 1.90 intake & the smaller ports & stock chamber of the earlier version.

 

Because they suck! The only ones in my opinion that MIGHT be worth buying are the MCR twin cam heads and that's a mighty big MIGHT. You would most likely have to do porting, even after paying800-1000 bones for these heads. Everyone is better off porting their stock heads. You get the biggest bang for the bone. I'm sure this has been stated more than 10,000 times but I didn't want to do all the reading. I just wanted to flap my trap.