"Jack's" Kickass D-Shaped Intake Ports! Alive and running

[Jack]

I'm a huge fan of Hugh and Jack. But let's get to where the rubber meets the road. Let's talk turkey. Let's get down to business. And let's see some dyno numbers ASAP!!!!

Cutting the turkey this early in the game would be pretty much useless has Hugh's head isn't any where near being "Tapped Out" to it's maximum ability and I've pointed this out to Hugh,so if he ever gets the itch to push this head to it's limit,"Watch Out" Can't wait till Hugh gets all the tuning worked out

 

[Jack]

So would Jack be willing to offer some porting services? I have a head sitting here that I need to have done.

Not at this time as mowing season is around the corner,that I have just so much going in my life and have absolutely no earthly idea what to even charge for the D shaping as you completely alter the port,real extensive stuff here

 

[angus67]

is that motor going in your digger, Hugh?

 

[Punkskalar]

is that motor going in your digger, Hugh?

I will put this engine in my test dummy (The Black and White bike) for tuning and running it some, then swap it over to the "Digger" bike when it is ready...

 

[OakBehringer]

Not at this time as mowing season is around the corner,that I have just so much going in my life and have absolutely no earthly idea what to even charge for the D shaping as you completely alter the port,real extensive stuff here

Put one of these engines on your mower and you'll have plenty of time at the end of the day.

 

[PHeller]

Slightly off-topic, but has the "reliable 70hp max" theory been debunked?

 

[Punkskalar]

Slightly off-topic, but has the "reliable 70hp max" theory been debunked?

I'd like to think so, seeing as how much better the Rephased Engines handle sustained high RPMS as well as higher RPMs in general. A dyno run would be nice on some of these engines. I have a customer who submitted a dyno sheet a few months ago to me from Australia who is supposedly putting down 79 hp on his rephased 840 and he was planning to retune and go back. I haven't heard back from him in a while though, it might have blown up

 

[PHeller]

The 2009 XR1200 make 78hp to the wheels, 2011 Kawasaki W800 makes 48hp, 2009 Triumph Bonneville makes 69hp to the wheels.

So if we could get a reliable (20,000 miles), 70hp, it'd be worth it.

That is until the price of Bonnevilles come down to XS650 prices. Which is doubtful.

 

[Oxblood]

2009 Triumph Bonneville makes 69hp to the wheels.

So if we could get a reliable (20,000 miles), 70hp, it'd be worth it.

That is until the price of Bonnevilles come down to XS650 prices. Which is doubtful.

I wish the Bonneville got 69, my 2007 puts down a mind numbing 50.51 at the wheel!

 

[Punkskalar]

Remember, at the wheel, and at the crank are VERY different numbers. What the factory typically rates is at the Crank (its higher, due to less parasitic drag/loss) as it looks better on paper...

Most Dyno's that we will see will be Rear Wheel HP/Tq

 

[Jack]

The 2009 XR1200 make 78hp to the wheels, 2011 Kawasaki W800 makes 48hp, 2009 Triumph Bonneville makes 69hp to the wheels.

So if we could get a reliable (20,000 miles), 70hp, it'd be worth it.

That is until the price of Bonnevilles come down to XS650 prices. Which is doubtful.

60 to 70HP will depend on several components, carbs,exhaust system,bore,compression,cam choice and last the key element would be the head with the right balance factor of "Velocity & CFM". There's an XS enthusiast (name unknown) who's using the Lillie head and Shell cam and he's putting out close to 66HP I believe but don't hold me to it. With the right parts anything is possible

 

[Jack]

Slightly off-topic, but has the "reliable 70hp max" theory been debunked?

The "Aussie's" with their stroked out XS's have kind of debunked that but if you push anything beyond it's capabilities something gotta give. Also you gotta keep in mind that you won't be pushing the engine as hard as they do in racing,so the stress loading of the crank support webbing will be minimal

 

[650performance]

Tony Guest's 750 street tracker has a Lillie head, 10 - 1 c.r. and a slightly advanced Megacycle 30 cam and generates 69 RWHP on a Dynojet 250. A street tracker I had in the '90s also had 750 cc, 10.5 - 1, a Shell #1 cam, Lillie head and generated 67.5 RWHP on the Vance & Hines dyno.
So yes, you can get these power figures along with reliability and decent street manners, but as Jack says, the combination has to be right.
Ultimately, of course, there is often a huge disconnect between hopes and reality, and if you're going to go down the More Power Road rely upon real data to tell you when you've crossed the finish line.
And, by the way, so you have a sense of what at least one of these porting solutions costs, you can have your own head CNC ported to the Lillie specs for $760 (porting only, no guides), and is available through Michael Morse at 650central.com.
Craig

 

[650performance]

As a point of reference, the following info may be of interest to those following this thread. Engines can be ported with any number of goals in mind ranging from enhanced streetability to drag racing. What follows is the stock vs. modified flow numbers for the Lillie head. Competition CNC, in Oakville, CT ran these numbers on their Super Flow 600 bench in September 2008.

COMPARATIVE FLOW NUMBERS
STOCK & MODIFIED XS650/750 CYLINDER HEADS

Test Conditions:

The stock head is not modified in any way and has been bead blasted to ensure the ports are clean and fitted with stock valves.
The modified head is the Harry Lillie modified “master” used for modeling the CNC porting program and has the modified, oversize XR valves. Both tests were conducted within a half hour of one another on the same Super Flow 600 flow bench with the same operator employing the same fixtures and procedures. Both were tested at 28” pressure.

The results are expressed as a percentage difference at each valve lift increment. I am not sending out the flow numbers because your flow numbers will be different on another bench, and I don’t want to get into discussions comparing apples to oranges. However, you should see virtually identical improvement over stock (castings do differ) with your CNC head. As you can see, on the IN port the mods really begin to kick in at .300” lift, while the EX porting becomes effective between .150” and .200”. The numbers underscore that the EX port is the most obvious limiting feature of the head and was one of the primary reasons the OU-72 was developed.

Flow difference from stock head
Valve life IN EX

.050” 0% +12%

.100” 0% 4%

.150” +2% 3%

.200” 6% 18%

.250” 6% 22%

.300” 9% 22%

.350” 19% 27%

.400” 37% 25%

.450” 46% 24%

.500” 56% 23%

 

[Jack]

Tony Guest's 750 street tracker has a Lillie head, 10 - 1 c.r. and a slightly advanced Megacycle 30 cam and generates 69 RWHP on a Dynojet 250. A street tracker I had in the '90s also had 750 cc, 10.5 - 1, a Shell #1 cam, Lillie head and generated 67.5 RWHP on the Vance & Hines dyno.
So yes, you can get these power figures along with reliability and decent street manners, but as Jack says, the combination has to be right.
Ultimately, of course, there is often a huge disconnect between to hopes and reality, and if you're going to go down the More Power Road rely upon real data to tell you when you've crossed the finish line.
And, by the way, so you have a sense of what at least one of these porting solutions costs, you can have your own head CNC ported to the Lillie specs for $760 (porting only, no guides), and is available through Michael Morse at 650central.com.
Craig

Wasn't for sure it that was you Craig with the Shell # pumping 67 HP
AS far as the real data goes in reference hopes and reality,when you build these engines on daily basis for customers, your ears become trained to the ever so slightly subtle changes in engine responses ,etc, and the D-Shaping of the intakes does indeed take it to the next level offering far superior performance over a round port allowing the ports entrance to be opened up exposing more area of the floor corners leading to the short turn thus increasing flow efficiency the entire width of the Short Turn with correct counter measures of course to combat increased port volumes and with increased port volumes,it opens the door to reduce the erupt turn at the Short Turn by means of raising the floor thus effectively reducing ports volumes while inherently increasing port velocity at the same time without the evils of diminishing flow any where in the curve with exception of flow biasing.

This D-Shape ported head has far exceeded my wildest expectations,took me awhile though but once Hugh and I get it tuned in,hows that MC Hammer expression go? "YOU CAN'T TOUCH THIS"
Glad you took the time to chime in Craig, later

 

[Jack]

As a point of reference, the following info may be of interest to those following this thread. Engines can be ported with any number of goals in mind ranging from enhanced streetability to drag racing. What follows is the stock vs. modified flow numbers for the Lillie head. Competition CNC, in Oakville, CT ran these numbers on their Super Flow 600 bench in September 2008.

COMPARATIVE FLOW NUMBERS
STOCK & MODIFIED XS650/750 CYLINDER HEADS

Test Conditions:

The stock head is not modified in any way and has been bead blasted to ensure the ports are clean and fitted with stock valves.
The modified head is the Harry Lillie modified “master” used for modeling the CNC porting program and has the modified, oversize XR valves. Both tests were conducted within a half hour of one another on the same Super Flow 600 flow bench with the same operator employing the same fixtures and procedures. Both were tested at 28” pressure.

The results are expressed as a percentage difference at each valve lift increment. I am not sending out the flow numbers because your flow numbers will be different on another bench, and I don’t want to get into discussions comparing apples to oranges. However, you should see virtually identical improvement over stock (castings do differ) with your CNC head. As you can see, on the IN port the mods really begin to kick in at .300” lift, while the EX porting becomes effective between .150” and .200”. The numbers underscore that the EX port is the most obvious limiting feature of the head and was one of the primary reasons the OU-72 was developed.

Flow difference from stock head
Valve life IN EX

.050” 0% +12%

.100” 0% 4%

.150” +2% 3%

.200” 6% 18%

.250” 6% 22%

.300” 9% 22%

.350” 19% 27%

.400” 37% 25%

.450” 46% 24%

.500” 56% 23%

When porting heads for practical street usage with average cam lifts ranging from .360 to.390,little is gained when the higher percentages of flow peak near .450 to .500 lift. One would gain a broader power band if the flow gains starting peaking hard around .250 to .400. You're wasting valuable resources that would other wise be of greater usefulness in the lower spectrum of the flow curve in my opinion. This is where the D-Shaped port plays it's Aces

And when trying to calculate theoretical HP based off flow data,one doesn't use percentages for calculations,one uses CFM gains obtained from testing and on average one might see 10% fluctuation amongst benches but at least it gives a paper plotting baseline in generalizing engine HP potential.

And for example a Lillie head at .200 lift roughly generates a flow of 113 CFM and my D-Shaped port at.200 lifts flows 119. Now when comparing gains at .300 lift ,the Lillie head flows roughly 152 CFM and my D-Shaped ports flows 181 CFM, now that's 62 CFM gained from.200 to .300 lift and at.400 lift the Lillie head flows roughly 187 with a continuous rise to.500 lift,now with the D-Port at .400 lift it's flow peaks out at 201 CFM just as intended, the D-Shape Port just packs a bigger punch and will produce more useable HP down low for practical street riding,along with higher cylinder packing efficiency and of course will depend on how much the floor is raised and how the Short Turn Radius gets re-worked but it's there cuz I've reduplicated these results with back to back flow testing,there's no blowing smoke up ones ass from me.

 

[650performance]

Jack, those intake port numbers are really remarkable. The curve that is produced by your lift vs. flow data points almost exactly parallels the factory OU head intake flow pattern, which also essentially peaks out at .400 lift.
You may have made the breakthrough that has eluded others who have attempted to find more power from the standard head casting.
You talk about your numbers being optimum for "practical street riding," but actually this is of equal (if not more) interest to both dirt track and road racers.
You may find yourself in a new business venture ... there are plenty of guys in the racing community who want, and can afford, whatever it takes to provide them with a meaningful performance upgrade.
I am really looking forward to seeing how Hugh's engine performs on the dyno.

 

[Yamaha_chop]

Loving all the work going into this engine guys

My personal approach to more power has always been throw a bunch of boost at it. My Dodge neon I had I started out with a bunch of bolt ons, went mildly quick, then I built a turbo kit for it and that was much more effective. And the motor was dead reliable too. Then I took the turbo off and built a supercharger system for it using a roots blower. Again very reliable and good power.
I feel that keeping the engine mostly stock, then boosting is a good compromise, because during 80% of the run time the bike is not under boost, and is running at stockish horsepower levels, so no danger of failure. It only has to endure much higher outputs under severe loads, so I just rely on the odds to be in my favor

With my bike, I'm hoping to get it running cleanly on around 10psi at first, then after its sorted and I have my backup engine ready, I'll start turning up the boost and see just how much power I can make before something lets go.

Now power delivery is a different story. I'm sure an engine like yours will have much more initial punch to it, and that's a lot of what makes riding fun. What is the overall goal power wise with this?

 

[crashcourse]

I've been thinking about this porting job for about a week now, or since I saw the original post, and I found a question.

How do you transition from the round carburetor exit to the D shaped intake port? In the pictures there doesn't seem to be a smooth transition, which would introduce turbulence and hurt your intake airflow.

 

[Jack]

Craig...Interesting info regarding flow similarities of the OU head,had no idea. The D-Shaping isn't a new concept,I'm just puzzled why no one's taken advantage of it's benefits.

Haven't really decided what to do if all the testing pans out but really can't go into a lot of the port dimension details either,at least not now.

Hugh was really anxious in getting his head mounted,so there still are some areas that could be addressed if he so chooses but yeah, it'll be interesting to see how it all develops after tuning