Hi guys. Got a question for all you builders out there.
I've just recently got my hands on a "Dan Vance Racing" 50mm TB. It is the stock TC96" that's been bored out. Also has some shaping done with metal putty down the back of it to help with flow.
my question is, could this offer any improvement on my 09 fxdb that just has a basic stage 1? Of course I will get it dyno tuned after install with sert.
Anyone out there done this before?....what happened?
I know cams, heads or big bore would be the ideal first choice for performance upgrade but this TB was a freeby so hey.....?
Cheers in advance for any feedback.
Dan
suck it & see
get rid of those epa cams the rest is good
Had one of those and worked very well. You need a complete K&N filter kit to get the full potential from it, those S.E. (screamin chicken) filters and 90 degree bend filters are more for looks/posing than real world performance. K&N are better filters and cheaper in the long term as the filter is a reuseable one. Having a genuine performance part in a system if the previous part cannot supply enough air to get the full potential out of it. The air system will only work to the biggest restriction. The Harley ones are designed for looks and appearance, not performance. If I get some spare time in the future will do a write up on the difference. The one you have will still out flow the 50 mm S.E. one if you need the higher airflow later on.
Thanks mate.
i do have a K&N filter already, should have clarified.......hi flow filter and Bub Straightaways true duel pipes.
i guess what I'd like to know before I put it on is are there any possibilities of a negative effect on performance if it is not matched with ported heads and cam upgrade? Just purely stock internals.
If anyone has done it, tell me how it went.
I'll most likely put it on anyway as I'm a serial tinkerer
Let ya's know how it goes for those also curious.
cam andrews 57 , as bob said , the manifold and throttle body should be fine , dan isn't stupid , cheers
Yeah, I had a look at Dans website. Certainly knows his stuff! I actually emailed him the same question but didn't hear back, so I threw it on here.
Would love to do cams as well but need to save pennies for our bathroom reno........I know, I know... I need to get my priorities right.....mates have already told me several times
might hang on till I get cams and do it all at once.
cheers for the advice fellas.
A lot of it has to do with the shape of the airflow. Adding yet another 90 degree bend and the shapes and profiles of the tract is just another restriction. Will have to draw some little pictures again with diagrams and explanations. Harley's must have one of the, if not the poorest inlet tract design of any motor cycle made today, its more on a par with a vintage tractor than anything else I've seen, its 1940's technology. Jap bikes a third of the capacity of a Harley have similar power outputs. The inlet tract design on my 1990's cheapo Bunnings lawnmower is better than the one on my 21st century Harley. Not this week though, under the pump, need to do the things that matter first.
Still like riding my Harley though, despite all its short comings.
nope not good enough we want pictures and drawings
And a suggestion as to the best air filter for the 58mm Throttle body.
Cool. I have found the heavy breather works better without the sock in heavy constant rain.
Sorry for the delay, many of the things I want to copy and paste onto here will not work, after multiple attempts this is the best I can do, getting sick of typing a page of stuff and having to delete it all when a screen copy and paste goes wrong. AM NOW GRUMPY. Will put more on in the future, taking my own pictures so I can put them on here to illustrate stuff. Have stayed away from momentum to keep things simple, as high velocity air fills cylinders better than low velocity air.
Important things to know first, Bernoulli, Reynolds, Darcy and more than a few others developed fluid flow formulas centuries ago for fluid flow in pipes and rivers. This was a long time before we managed our first powered flight, so if you think Bernoulli's principle only applies to an airplane wing it is not so. Air is considered a fluid and uses the same formulas or derivatives of the old original fluid flow formulas. They are used for gas flow in nuclear reactors, jet aircraft, ships, pipes or slop in sewerage systems. They are aided by loss tables, looking at them will not make you an engineer but it will give give a good guide to the loss that fittings and bends have.
The mathematics of these formulas can quickly become complex as rates of change are involved so triple integration is not unknown. To keep it as simple as possible there are tables available to work out the loss coefficients of various bends and pipe configurations. What can make it confusing is that the loss due to a bend is called a minor loss, a major loss is the drag on the pipe wall. BUT a car or bike motor inlet is so short that the surface drag is so small as to not be worth considering. For example a 50 mm pipe (same as a throttle body) would be over a hundred metres long or longer to need the major losses to become important. Mirror polishing an inlet manifold makes almost zero difference as the surface roughness is about 0.2 mm, so all you are doing is making the diameter, 0.2 times by two = 0.4 mm bigger. The velocity on the pipe wall will still be zero, can't put a pipe velocity profile picture on here, but is the same as a river, zero against the wall and fastest in the centre of the river, might have to draw one. Remember these formulas were developed for something like the pipe system for a city which would have kilometres of piping, then it would be a major loss, the terms come from the origin of the formulas. We are only really interested in the minor losses which in most tables are given as a K value, there are more than one type of K value, K with a small L next to it is the one you want. (don't know how to type it here other than take a picture of one I've written and post it on here). Google "loss coefficient in pipes" to look at the tables, click on images and a mass of tables and pictures are available CAN'T PASTE THEM ON HERE. Guess the web site was made for quick chats and bike pictures. The loss coefficients for something like the T shaped inlet manifold will be there somewhere as well.
The loss coefficient is multiplied by velocity squared in the formulas. This means that if at idle (1000 RPM) the motor was drawing air at 1 metre/second the loss coefficient for a sharp 90 degree bend is 1.10, so we have a loss of 1.10. If at 2000 RPM it was taking air at 2 metres/second the loss would be 2 squared times 1.10 which = 4.40. If at 4000 RPM it was taking air at 4 metres/second the loss would be 4 squared times 1.10 which = 17.6. See what is happening, 4 times the speed and the loss factor is now nearly 18 times bigger. I'm trying to keep it simple, but as the inlet reduces in diameter the velocity will have to increase so the loss coefficient will increase even more. The ports are a smaller diameter than the throttle body so they have a higher velocity and a bend here is worse than one where the air is travelling slower.
The K value losses are all added together so its simple really, more bends or restriction the more losses.
The smaller (sharper) the radius of the bend the higher the K value. The high flow Harley performance (joking) heads have bigger ports but the ratio of the radius of the bend to the diameter of the bend has now become worse so the K value increases = greater loss.
It is very easy to picture by imagining the inlet system like a race track, bends slow you down. To imagine it properly you cannot cut the corners or overshoot the bends. Do the whole track with one wheel touching one road verge, or stay in the centre of the roadway, The more you have to slow down to keep on your flow line the greater the restriction loss. It is the same as travelling in a plane or boat, as they usually have a fixed throttle so you can see what is happening, straight line = speed stays the same. Sharper the turn the more speed is lost, planes lose height and boats get slower the sharper the turn, Exactly the same thing happens with pipe flow.
Can't seem to write below a picture, am ready to give up now ????
Picture 1 is the worst type of a bend even though it is a square pipe, still ugly but easy to make.
Picture 2 is a Harley high performance thing (joke), sharp 90 degree bend, am worried about the shape of the base of the aircleaner, from the picture it does not look good either, see picture 6.
Picture 3 is a sharp bend that still needs to have a reasonable flow, not as smooth as desired but the radius of the bend is much better (bigger bend radius).
Picture 4 is an old bike with gentle bends, very desirable, well done, excellent radius to diameter ratio on the exhaust and the inlet.
Picture 4 is I think a VMax, from air box to the combustion chanber there is one gentle 30 degree bend (big radius) and then the inlet valve angle. Probably has velocity stacks on each carby inside the air box. Japanese V motor making much more power than a Harley. It probably has 4 valve heads and a few other things, but it is a good example of a low restriction inlet tract. 170HP out of the box without having to spend an additional $12000 to get a bigger capacity Harley 120 motor which makes about 110 to 120 HP. Spend $12000 on the motor in one of these and truly frighten yourself !!!! The Harley Vrod designed by Porsche I think is similar to this inlet system. I can't help thinking that the designing a good motor is beyond the Harley engineers, its more of a vintage fashion statement from 1940.
Picture 5 is an attempt to show a Harley inlet tract, in real life I couldn't make the bends and curves as bad as they really are, including the big speed bump the air hits going from the inlet manifold into the head. Pots are the cylinders, small train is the inlet valve and T section at the start is the standard Harley aircleaner shape, see picture 6. The kids train tracks couldn't make one as ugly as it is. Won't get started on the throttle body shape today
Picture 6 is some diagrams of the loss coefficient on various inlet systems. First one is a bare carby or throttle body K value of 0.8. Second one is a standard 96 aircleaner base K value of 0.5. Third one is something like a big sucker aircleaner K value of 0.2. Velocity stack not shown here but its K value is 0.0, ZERO, NO LOSS. A K&N high flow air filter has a mini velocity stack on the end of the throttle body. Look up the website as I can't get the picture onto here.
Picture 7 is a I think Vmax inlet system. Didn't have enough train bits to do it complete.
Love your work Captain !! Funny thing is, most dyno testing I've seen prove they do work well. Go figure ! Probably something to do with intake plenum volume and runner length. I think the dominating factor with HD is the intake manifold, not so much the air cleaner. Another thing to think about is the venturi effect of air passing by the standard style air cleaner, trying to create a vacuum. Also, on another note, do some research on Bellmouth intake's (velocity stack).
A quick intro: http://www.autospeed.com.au/cms/article.html?&A=110771
Another short read if your bored:
http://www.profblairandassociates.com/pdfs/Bellmouth.zip
It was a bit rushed so maybe it is not clear enough.
If we take the velocity of the Harley air as 1 m/s at the aircleaner intake of 56 mm diameter. K value 0.5 ,
A bit further down there is a sharp step to the 50mm throttle body bore. The velocity here will be 1.25 m/s. Except because of the sharp step just before the butterfly and not blended gentle curve the 50 mm bore only really flows 47 or 48mm (look up vena contracta to see what happens to the flow lines) Haven't done the K as doing it from memory and don't have a standard one at home to measure.
At the t section and to the end of the inlet manifod with a diameter of 40 mm the velocity will be 2 m/s. Guessed the diameter again and not going to guess a K but a straight T has a K value of 1.3. From memory the Twin cam inlet manifold has a larger radius curve an is not a full 90 degree bend. so a wild guess of 0.8.
At the port the guessed diameter is 30 mm so the velocity will be 3.5 m/s. Don't have a head at home to measure the correct size or the radius of the curves in the head, so guessed again. Threre is a guessed 30 degree bend upwards going into the head and then a flip back the other way of a guessed 70 degree bend to go into the combustion chamber. I really need to know the correct numbers here to get the right K value, as the gentler the bend the lower the K value and every bit the radius of the curve is increased the K drops. Or the less severe the bend the better the flow. But there will be two restrictions of the two bends here. The big port Harley heads just have bigger ports, the very important radius of the curve to pipe diameter is worse which gives a higher K. They might flow more initially because the port is bigger but they will start restricting when the velocity gets high. They have poor velocity down low as well because of the big ports which is not such a good thing either. It just goes to show a big hole is not the answer. lol
As the k value is multiplied by the velocity at each part and then all added together. The high velocity parts of the system have the most influence on the flow restriction. In the Harley case that big speed bump the air flow has to go over to get into the combustion chamber would I think be the biggest restriction, only one valve would not be helping either. A single valve is not that bad always, because I think it was the Suzuki dirt bikes only had one for years and they went alright, just a much better designed one. All the restrictions are added together giving a total.
Compared to the Vmax there is 0 for the inlet if it has velocity stacks, Not going to count the butterfly in either system as they both have one an need something to control the airflow and both use the same system (they have K values as well which change as they open and close). A 30 degree bend with a guess K of 0.1 then the inlet valve. Not going to guess a K for the inlet valves as it would depend on many factors, no guessed K for the Harley inlet valve either either. There are a lot less K's or loss factors in the system used on the Yamaha. Also don't know the bore sizes for the Yamaha and guessed the Harley ones.
There are other parts to the formulas, I have taken only a part of them to try and illustrate what is happening and to try and give a picture of what is going on and the difference between the two systems. There are a lot of other factors involved which make it complicated to a high level mathematically, beyond me anyway. I just think of the pressure waves and stop just after that, there are formulas for them as well, the same ones used for water. You can see them at work when a wave hits a wall and the wave that comes back out, is the same, just that we can see the one in the water. Traffic on a highway works to the same or simular formulas and a stoppage on the freeway will cause a wave of brake lights going back through the traffic, same thing happening.
BACK TO WORK
edit in. If the velocity is squared then multiplied by the K factor then the velocity in the port ( if I have guessed the diameter right) is 12 m/s, (only 1 m/s at the aircleaner opening) so the difference in the port and valve area is very significant. 12 times the difference if my guess's are right, this difference will increase to very big numbers as the velocity increases ie revs go up. As it won't be 3.5 squared but bigger numbers squared. The 1 metre per second at the aircleaner was just a guess to have a number to start with. Any little improvement at the highest velocity point is going to make a much bigger difference, guess thats why multi angle valve grinds, quick opening and closing cams, good porter etc work. Any reduction in the K factors is going to help the motor breathe better. I havn't looked at this stuff for years but 100 m/s or 300 feet/sec rings a bell as a good speed to have. Remember the drag increases at velocity squared, High velocity is better than low velocity as the airflow then has momentum but there are limits to how much can be pushed or sucked down a pipe according to its diameter if all the other facors stay the same. Velocity and momentum are good to have. Thats why the longer smaller diameter exhaust pipes give better torque and economy than short big diameter ones which only work at peak revs. My wife's car has variable length intake runners to boost torque at low revs, the intakes lengthen and shorten. The jap bikes have numerous names for variable intake and exhaust systems which vary according to the revs or load. The intake and exhaust flows need to be matched to the job they are wanted to perform at. Make the inlet or exhaust too big or too small with the wrong length and it is not working at its optimum for a certain airflow. Unless your drag racing then I would try and keep the end of the exhaust past the back wheel. Touring bikes have the same motor and make more power with a longer exhaust, ever wondered why.
Too much work to change them unless you have a CNC and move or modify the fuel tank. One guy grafted some Ducati heads on to get around it. I just got a good porter from the US with a ton of experience and results in the racing scene to do mine, used Dan Vance each time I get a new set of heads (new to me as pick them up for not much on US Ebay and only overseas postage one way, a lot of sellers won't post to Aust as Ebay fees are on postage as well). Not tried the local guys though, I trust a CNC to get it right every time.
Better late then never Dan Vance ported a stock Delphi 46 mm body for me but he insisted on the heads flowsheet numbers before he would start. The first ride after fitting the 50 mm ported body while Vtuning I hit a speed bump giving myself a bad case of whiplash. I give Dan credit because he found the bottleneck on my electraglide as it rips when I get on the throttle now but its very snappy down low with the 5-6 wood cam and his throttle body and opoxy work on the inlet manifold.
