Couldn't have said it better myself.

 

No, actually, I used an old big block Chrysler and an old Big Block Chevy as examples of how more displacement doesn't necessarily produce more power.... nothin' fancy .

And today's Harley is far from "a 100 year old tractor power plant". It is more pseudo-retro than actually retro, and includes things like modern piston and combustion chamber shape, fuel injection and advanced electronic engine management. The 45 degree configuration with the common crankpin is about all that remains from 100 years ago (except that three models are no longer 45 degrees, and at least one model no longer uses the male/female connecting rods).

By the way, the megabuck-supercar challenging stock ZR1 Corvette (638 horsepower, 205 mph) is still a pushrod operated 2-valve-per-cylinder engine.
And it's smaller displacement than some of the other Corvette engines, despite being their most powerful offering.

 

Thing is there are many upgrades for your motor and it seems the first thing most do is stage one pipes and air cleaner you pick up a few ponies with that Then it seems like some add cams to that equation that's another few after that what I see most of the time is the big bore kit which is probably a stage three and then there is the stage four motor all that with heads . I know that harley has stage kits mine is a stage four everything but a stroked kit. When I did my motor I went with screamin eagle at the time hardly was still selling performance parts and they were starting to get crap from the EPA boys they stopped selling pips that were not street legal they used to have pipes with the crossed flags which were not street legal it seems most of the stuff they sell not is street lea legal thing is I would rather have a built 95 over a street legal 96 pr 103 any day.

 

OK I give up, almost. However, I do take exception to "pseudo-retro than actually retro"; it would appear that you are much more familiar with the automotive world than the Harley world; just guessing. There is nothing "modern" about pistons and chamber shape; haven't changed in over 20 years. Furthermore to label the Harley engine management system as "advanced" is very much a miss; far from it as it hasn't changed in almost as many years as the piston/chambers. The only real change in engine management in recent years has been to the fuel management system and it is still lagging way behind the automotive industry. Hence the wide variety of aftermarket fuel management systems available to upgrade the tenability of the vtwin motor.

Now on the other hand, the stock ZR1 motor does have the advantages I cited in a previous post; metallurgy, machining tolerances, variable valve timing, water cooling, advanced engine/fuel management systems and many other advantages that I am not knowledgeable to list.

But back to the Harley context and the context of this forum; two motors, all things being equal, the bigger motor wins. Bottom line for the Harley vtwin is that displacement is still the single most COST EFFECTIVE upgrade one can make to the Harley vtwin motor. But, as always, that is JMHO and the exchange has been fun.

 

Vastly different than 100 years ago, which was one of the time stamps you used. Much of the change since the 1980s was lead by the automotive world, seeking better emissions and fuel economy. After a short time producing those nightmare "smog engines" which were way down on power, and had complicated fixes strapped all over the exterior, they discovered that even more could be accomplished (without the downsides) with a basic re-design of the combustion chamber, combined with more accurate fuel control. Advances continued in computerized controls, incorporating more and more engine functions.

Off the top of my head, the Shovelhead was the last Harley to use "hemi" combustion chambers, which had some huge problems. Even the modern "Chrysler Hemi" no longer uses those. They just call it a "hemi" for nostalgia and marketing purposes.


No, Harley's engine management systems come from the same manufacturers who supply the automotive trade, and these manufacturers are constantly refining their systems. They have extensive capability when it comes to changing parameters, and have some really sophisticated features, like the "ion sensing" detonation control.
When people choose "piggyback" style aftermarket tuners, rather than reflashing the the factory control module, it's almost always in an attempt to save money, or because re-programming the ECM seems too complicated. The factory control system is capable of doing the same things, and much much more.

A notable exception is some of the aftermarket systems intended primarily for race vehicles, which can have multiple rpm limits triggered by different switches or sensors, automatic triggering of multiple stages of nitrous according to gear or vehicle speed or elapsed time, varying boost level (turbo) according to what gear the vehicle is in or speed or elapsed time, etc. These are functions which most people will only need on a hardcore race-only vehicle. The factory Harley ECM is really quite sophisticated and capable. Buy or study some of the tuning and re-flashing software if you want to get a little idea of what-all the factory ECM does, and what it can do.

 

Mine to is a stage 4. It was born a little 88.... "that couldn't". It has the SE heads and they were supposed to be done, I will find out for sure here shortly. They are coming off anyway this winter so they will be going to my head guy to either have them done or done right and cleaned up. It is shockingly quick and more than I will ever use on a daily basis so I rarely get the urge to go with a 103 or a 110. Your best performance motors are when the entire engine has been addressed and then tuned and running in sync. I think if I was ever going to do it I would save until the motor could be addressed as a whole, not a part at a time. Thats just me.

 

You keep taking the discussion off to a comparison between the developments in the automotive industry to the current day Harley Davidson vtwin motor and, as I have pointed out, not a fair comparison.

This discussion started when you took exception to the "no replacement for displacement" phrase which, while dated, still holds true for the DIY Harley gear head guy that wants to build up a motor. There is no denying that, in the Harley world, all things being equal, the bigger motor wins.

Happy to continue the debate within the context of what kicked it off; otherwise and no disrespect intended, I don't need an education on what the automotive industry has and is developing.

 

It's a very valid comparison. Automobile and Harley internal combustion engines are much more alike, when it comes to operating theory, applied practice, and engine management systems than they are different.

And when I mentioned some of the sophisticated controls, like ion-sensing detonation management, I was talking about Harley engines. That's what they currently use. Last I heard, the Harley engine management is supplied by Delphi, which is primarily an automotive supplier. You may know them better as "Delco Electronics", which is the name they used when they were still a subsidiary of General Motors.

So you can make claims like the following till the cows come home, but they will still be highly misinformed.
Quote:
"Furthermore to label the Harley engine management system as "advanced" is very much a miss; far from it as it hasn't changed in almost as many years as the piston/chambers. The only real change in engine management in recent years has been to the fuel management system and it is still lagging way behind the automotive industry."

 

Wow man seems the thread is getting to deep for me thing is I have said this many times before and I will again. It's kind of nice to have all this power but what it really is would be called ego. If you have it and are afraid to unleash it what good is it. In reality there are very few places where you can roll off all that power without putting yourself in harms way. To many bad drivers out there to have to worry about at regular speeds. But we all get caught up in it. I hear guys saying I'm not going with fish tails I'll loose power that is the biggest joke I ever heard un less you are putting your pink slip on the line it means absoultly nothing a little lost here with a little gain there most of the time if you give up a little here you will gain it there meaning loose hp gain toqure or vise versa I spent plenty on my motor went as far as I could without stroking it which is not recommend on the b motor and if I did stroke it it would probably be in the bar hopper category and worthless as a riding bike. I never had my bike dynoed don't feel it's worth it. Rev the **** out of your bike you have to sign a wavier that if it blows up they are not responsible not to mention the cost and the fact three different operators would probably come out with different readings and in reality if your running the same **** as the next guy your results are going to be about the same.I think I got caught up in the motor thing because my older late brother was a stone cold biker and was running a 100 hp motor when it really was a big deal. It really meant a lot to him any way there are a lot of us who get caught up in it and spend a lot of money on it. But I would never let it stop me from adding a set of pipes I liked. I have found that a lot of people get on this site and think what they hear here is written in stone and a lot do the exact same thing and I am guilty of some of that myself unless you are doing fabrication chances are there are plenty of bikes that are the same just look at all the deluxes on this site newbie gets on the site ends up with fat spokes shotgun shock apes or beach bars fish tails 39 or 42 fender rails and so on if you can buy it and bolt it on it's all over the place every day another deluxe is done and they are all pretty much the same nothing wrong with it it's a thing of beauty. I am getting older do not see as good at night as I use to my reflexes are a little slower but it's still nice to let it go now and then. Ride safe be careful its the other guy most of the time

 

Well, we in agreement on that point but that is not what has been compared in the previous discussions.