Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Information For The New Harley Owner
Information For The New Harley Owner:
Plan Your Attack
This article is a must for the new Harley owner. “New Harley Owner” meaning anyone that has purchased a Harley and is thinking about performance upgrades.
The most important thing to remember is that the key to making a lot of power is in choosing the correct matching components and not necessarily choosing the biggest components.
I personally don’t care about the HP (Horse Power) ratings when it comes to Harley motorcycles. I do care about TQ (Torque). TQ is the “G” force that you feel when the bike is pulling hard during acceleration. HP keeps the momentum of the TQ going. Think of it this way: If you had six people pushing a car on a flat road from a dead stand still. After it got rolling, it would probably only take three people to keep it going. In this example the six people are representing TQ and the three people are representing HP. While pushing the vehicle on the flat road, you suddenly come to a hill. Do you want to keep the three people (HP) to push you up the hill or would you like to use the six people (TQ) to push the vehicle up the hill.
I said all of that to show the importance of TQ. Here is one thing to also remember: HP will follow TQ. If you increase the TQ the HP will also increase. Here is why: A dynamometer uses this formula to calculate HP. TQ x RPM / 5252 = HP. Look at any dyno graph and pick a RPM and see what the TQ is at that RPM. Now multiply the TQ by the RPM. Divide the product by 5252 and it will give you the HP at that RPM. If it doesn’t, then you need to question the accuracy of the graph.
Most high HP engines are designed to have the peak TQ further up the RPM range. Take the graph from above and move the peak TQ 1000 RPM up the RPM range and do the same calculations and see how the HP increases. Peak TQ was 103.7 @ 3600 RPM. The HP @ 4600 RPM is currently 85 HP. Multiply the peak TQ (103.7) x 4600 RPM divided by 5252. The HP @ 4600 RPM would change from 85 HP to about 91 HP. This increased the HP, but it takes longer to get to that 91 HP.
Going back to the illustration of pushing the vehicle up a hill…why do you have to gear down on your motorcycle to go up a hill? The answer is very simple. You have to get in the RPM range where the TORQUE is located. These heavy bikes were designed to produce low RPM TQ, not high RPM HP. So why not enhance what the bike was designed for instead of revving the crap out of the bike to get to the power band.
Torque Torque and more Torque!
Horse Power is for winning Dyno Shootouts. Torque is for winning races and beating your buddy from stop light to stop light or pulling away from your buddy with a fourth gear roll on. I know what you are thinking…My bike has won all of those dyno shootouts. I actually designed the engine for TQ. Remember earlier when I said that HP will follow TQ. So why not take advantage of the HP when generating so much TQ? Remember that my bike has around 20 more in TQ than it does in HP.
Crotch rockets are light, which enables them to design the engines with the peak TQ very far up the RPM range. They usually have twice as much HP as they have TQ. Take a dyno sheet from a high HP crotch rocket and move the TQ way down the RPM range (around the same TQ peak as a Harley) and use the HP formula described earlier (TQxRPM/5252) then watch the TQ increase and the HP decrease. Moving the TQ way up the RPM range works well for the light 400 - 500 lb. crotch rockets, but add the weight difference of the Harley such as a bagger and see just how fast it will be then. It will still have a high MPH, but it will take a long time to get there.
Watch this video of my bike racing against crotch rockets. I out ran them with TQ, not HP. At the time that this video was shot, the bike stopped making HP at 5500 RPM.
When planning your performance upgrades, target high TQ, not HP. In this article I will give suggestions of what components to use to increase TQ. I will also explain briefly why these parts increase TQ. For more detailed information, there will be links to other articles that will explain the theories further.
When choosing a cam set, look for a cam that has a short duration (no more than 240 degrees) with an early intake valve closing no later than 20 degrees. There are several good high torque cams on the market.
When choosing a cam, be sure to choose a cam with enough lift that will work well with future performance modifications. The valve size and lift will determine what RPM that the engine will be capable of making HP. Click here for more information on the MACH Index. When using stock intake valves (1.8”) you will need at least a .550” lift to make HP up to 5500 RPM.
If you decide to increase the engine size to 103 ci, the .550” lift cam will only be able to produce HP up to 5000 RPM. You would need to increase the intake valve size to 1.9” or increase the cam lift to .575 to make HP up to 5500 RPM. Also keep in mind anytime that you increase the cam duration, you will lower the Dynamic Compression Ratio.
Here is a link to an online MACH Index calculator. Wallace Racing - Mach Index Calculator
Choose a good 2 into 1 exhaust. The 2 into 1 pipe will create more TQ. The true dual exhaust may sound good, but they won’t make the TQ like a 2 into 1 pipe. Another thing to consider when choosing an exhaust is that an exhaust may work well with a certain cam timing, but may not perform well with a different cam timing. The timing of the exhaust valve closing HAS to match the timing of the exhaust waves. This is why when you change the exhaust and the bike makes less power. For more information on this subject, click this link.
Anytime that you add performance upgrades, you will need to have the fuel injection remapped. The SE Race Tuner, Super Tuner and the TTS Tuner are the better tuners on the market. They have more manipulation capabilities than the other tuners on the market.
In conclusion: I would suggest that you choose a cam such as the Woods TW-7H if you are planning to increase the cubic inch to 103. You can use a cam such as the SE-255 if you are not planning on a 103 ci increase. Use a good 2 into 1 pipe such as the D&D Fat Cat, D&D Boss, V&H Pro Pipe, R&B LSR pipe.
Torque is great no doubt, we all love that pull, however high torque numbers and low HP numbers = a big V-Twin that for it's mammoth size is running lousy times and has lousy HP to CC ratios. This has been the traditional Harley for years - forever in fact. Great for the street and light to light action - maybe.
Oversimplified, I view torque as a byproduct of HP, most Everyone builds for big HP and the extra torque is an anticipated benefit.
Now, you can build for torque with specific head, pistons and cams designs but then you would have a Dodge Truck or a John Deere. You have to have the horsepower.
The Harley PR machine and the loyal following have bragged and boasted about torque for years but frankly it's cause that's all they got and lots of it.
Love my hogs, not doggin' anyone here but just sayin'!
Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Re: Information For The New Harley Owner
This is the great thing about forums. Everyone can voice different opinions and they can be debated.
“however high torque numbers and low HP numbers = a big V-Twin that for it's mammoth size is running lousy times and has lousy HP to CC ratios”
The bike that I play with at the track is my daily rider (Ultra Classic). The scales at the track show the bike and myself weighing in at 1100+ lbs. It has run 7.3 seconds at 101+ mph in an eighth mile. Using a 0-60 mph calculator, it puts 0-60 at 2.58 seconds. What would happen if I put a Hyabussa engine on my bike, which is rated about the same HP as my bike? I would lucky to out run a stock HD unless I re geared the bike to keep it in the Torque range.
“Oversimplified, I view torque as a byproduct of HP”
Going back the dynamometer formula, TQxRPM/5252. You can’t have HP without TQ.
High HP engines are good for light bikes and open track racing, but not for a 800lb HD.
The HD was only designed for 130 mph (look at the tire ratings). How many people out there (besides me) frequently run above 120 mph. Building a high HP motor, with the TQ way up the scale, will win the bragging rights of a dyno shootout, but my high TQ bike will kick their azz on the street and 1/8 mile strip.
I would like to see a Hyabusa put on weight to equal my bike and rider and race the 1/8 or even the ¼ mile. It may win on the salt flats.
This article is showing a different view about HD power. People can build them for high HP and can keep gearing down to get in the TQ rpm range. Or they can build a high TQ engine that will run smoother and get you up a hill and around a curve without having to gear down. It’s their choice.
1/8 mile yes I guess I'll give you that one. But the 1/4 is thee test and HP will always win out. Besides, you're running nitrous and a very big inch motor so you DO have the HP numbers when spraying and I'm sure you did some intake and exhaust mods as well. Loose the nitrous and my point is made, high torque numbers are great but you need that HP to make times.
Case in point, the Revo is a small displacement engine built for higher Revs and HP, short (square) stroke, high compression pistons, ect. It's torque numbers are not bad but less than big brother and come higher in the rpm range. However, it has an incredible HP to CC ratio for a big twin (stock) - 1hp per 10cc's and at 650# can turn low 11's in the 115mph range. With nitrous most couldn't touch it. Top speed is 150mph and it gets there quickly, the gearing taps at 150 out but there is throttle left. Big Hp, OK torque numbers!
Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Re: Information For The New Harley Owner
Nitrous has nothing to do with it. It only increases what you already have.
Here is a dyno sheet when I first installed nitrous using a .030 jet
Before
After
“The videos are a bit vague!” I don’t know what’s vague about it. It is what it is. A daily ridden Bagger with a lot of TQ that can beat crotch rockets on an 1/8 mile track.
Again…equalize the weight of the bikes that you want to compare and see how well they do against each other.
You are talking about two different categories of bikes. I’m talking about 800 lb Harleys that need more TQ than HP for the average Harley rider. You seem to want to debate 450 lb bikes with small high revving engines having high HP. Example: Take the high revving, small cc engine in a light sports car then put that engine in a Cadillac. Once you finally got it going, it could probably go OK. I don’t think that I would want it as a daily driver.
I sponsor an AHDA bike in the S&S 124 class. This is a “street legal” class. When I dyno tune the bike, it has 150+ TQ at 4000 rpm with 130 HP at 6200 RPM. The TQ max out at 5400 RPMs.
Just for curiosity, maybe someone could find out the max TQ/HP/RPM of the Harley nitro bikes. I can find out at the Rockingham race next month.
Twinpeaks and I have "agreed to disagree" about this subject in the past. I have one simple point to make here - Torque is a measured property, horsepower is a calculated number and, therefore, arbitrary. So whatever your HP and RPM goal may be, in order to attain that goal you are actually modifying the engine to move/adjust the Torque curve. In any acceleration contest the real test is where the tire meets the track and the amount of tractive force that is applied. The tractive force is a function of the Torque available, final gearing, tire diameter and tire/pavement traction.
again, you keep talking the 1/8 mile? Show me some 1/4 mile results where hp finishes off the race.
I don't recall debating 450lbs crotch rockets, I did refer to the 650lb V-Rod and it's lower torque numbers and low 11's.
I'm not saying torque ain't good, love it, in fact chose a pipe, stacks and tuned my V to get more down low, lowered the power curve as well. Love the pull, but it's the 110 hp to the back wheel that literally eats up all the torque happy Evo's, even light to light. Run with guys with big inch, stroked out shovels and Evo's, torque up the a$$, great runners all but can't touch me.
There's an old saying around the track, can't recall it exactly, something about torque and HP, referencing torque but that HP wins the money............................anybody?
Twinpeaks and I have "agreed to disagree" about this subject in the past. I have one simple point to make here - Torque is a measured property, horsepower is a calculated number and, therefore, arbitrary. So whatever your HP and RPM goal may be, in order to attain that goal you are actually modifying the engine to move/adjust the Torque curve. In any acceleration contest the real test is where the tire meets the track and the amount of tractive force that is applied. The tractive force is a function of the Torque available, final gearing, tire diameter and tire/pavement traction.
This debate will rage forever I suspect but the above article is very good reading and makes a case for both sides. We will, I'm sure interpret it for our own interst!
Thanks for the link Twinpeaks. I pretty much agree with Mr. Augenstein, I'm sure he'll be pleased Thomas Barber proposed to debunk Augenstein's article, but he only posed assertions which he termed "facts". Without the classical physics that Augenstein used as backup, his "facts" have no merit so I discounted his two articles.
You have obviously put some work into your V-Rod, which I always thougt was an impressive machine. (Saw the show on the V-Rod development a few years ago - classic Project Management / New Product Development case that every new engineer should be required to watch) When you say Horsepower, I'll smile and think Torque/RPM. We're communicating however it comes out.
Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Re: Information For The New Harley Owner
Quote:
Originally Posted by Twinpeaks
again, you keep talking the 1/8 mile? Show me some 1/4 mile results where hp finishes off the race.
The only personal example that I can use is our S&S 124 Dyna that I sponsor and tune. 150 TQ @ 4000, peak TQ @ 5300, 138 peak HP at 6200.
Show me some 1/4 mile results of High HP baggers vs High TQ baggers.
Screamin’ Eagle® Pro Racing:
Information
Horsepower and Torque
While many judge a motorcycle’s performance solely in terms
of horsepower, torque is an equally, if not more, important factor
in the equation. In a nutshell, torque is the twisting force that
gets your bike moving, while horsepower is the effort required
to keep it moving—meaning that torque influences acceleration
and horsepower determines velocity. Your goal should be to
reach the balance between horsepower and torque that most closely
matches the performance you need. In general, if you’re running a
lightweight bike, getting more horsepower at a high rpm level is
the primary consideration, since you won’t need as much
accelerating power in the low to mid rpm range. For a heavier
bike, generating torque in the low to mid rpm range is essential
for getting off the line in a hurry.[/QUOTE]
Again, the article was intended for the new Harley owner to realize that heavy Harley's need TQ more than they need HP for the normal rider. I build and tune bikes for a living and have found that the majority of the my Harley customers have one common complaint..."My bike has a lot of HP, but I have to rev the carp out of it to get to the power. When I'm riding double, I'm continually having to keep it in the lower gears." Unfortunately these problems are caused by poor advise from people such as yourself advising that they need to plan their engine build for high revving HP.
A couple of weeks ago, I was on the interstate and a Ferrari pulled up behind me. He stayed there for a minute or two. My license plate has VRYQUIK on it, so I often get bikes and car wanting to race. The Ferrari came up beside me in the fast lane, geared down and took off. I like to play, so I pulled out and got behind him. He was cruising at 120 mph, then he pulled in the right lane, so I pulled up beside him. I couldn't see the driver because of the tinted windows, so I just gave him a big smile (cruising at 120 mph) then I geared down and hit the throttle, pulling an instant 4-5 car links from him. Then I slowed down to get beside of him again. He then slowed down to 70 mph.
I couldn't do that with a low TQ 850 lb Bagger.
It's not unusual for me to cruise the back roads in a gear the has the RPM around 1500 - 1800 and throttle it when I need it without gearing down to keep the bike from bogging out.
I'll stick with my TQ
I take it that you have a V-Rod? If so, what ETs & MPH does it get at the 1/8 and 1/4 mile track?
Here is a video of the same bike after I changed the cam timing 11 degrees at a dyno shootout in Greensboro NC.
Information For The New Harley Owner 
Re: Information For The New Harley Owner 
Thomas Barber proposed to debunk Augenstein's article, but he only posed assertions which he termed "facts". Without the classical physics that Augenstein used as backup, his "facts" have no merit so I discounted his two articles.
) When you say Horsepower, I'll smile 
and think Torque/RPM. We're communicating however it comes out. 
Linear Mode
