MadBill wrote:i think if the texturing resulted in a 'virtual cross section change', it should be evident in the shape of the power curve, i.e. biased slightly to the top or bottom of the range.
What would you expect to see from better atomization/burn alone?
Quotes from Larry's article.
We kept testing this on the next 5 or 6 various types and engine CID sizes, grinding over the previous 60-Grit finish with the rougher alumina burr finish and gaining anywhere from 10 to 15 HP and lower BSFCs and sometimes shifting Peak HP RPM point 100 or 200 RPMs higher.
Again, I removed the heads and went back to 60-Grit finish everywhere. Back on the chassis dyno it lost the 17 horsepower and was basically back to where the engine was originally. That was the only A-B-A tests I've done so far. I wish those tests would have been on my engine dyno instead. We kept going with the rough carbide finish everywhere in the intake, exhaust ports, chambers and intake manifold from that point on. So far every engine has responded with 15-25-plus horsepower increases, a wider power curve, sometimes 100 to 300 higher RPM point of peak horsepower, less fuel consumed on the Dyno ( lower BSFCs ) and dryer exhaust ports.
On the flow bench, basically no flow gains I can measure from roughing up the entire heads/manifold surfaces. On the dyno and down the dragstrip, we consistently see more HP and quicker ET/MPH times. In 2010 Jeff Colletta won the NMCA NPS Championship with the rough carbide finish everywhere in the intake and exhaust ports, chambers, and intake manifold.
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
GARY C wrote:.. What would you expect to see from better atomization/burn alone?...
Larry doesn't mention any effect on optimum jetting or SA, but one indicator of better atomization would be the need to jet it down some. Another might be leaner AFRs as reported by the flow meters, while the WBEGO readings stayed much the same.
I'd like to address the other side of the equation and add: If as far as the engine was concerned, texturing changed nothing other than reducing the effective CSA, I would expect an increase in low/mid-range power and a drop off at the top end. Larry reports quite the opposite, which suggests any such effect is minor or non-existent.
Rick Finsta wrote:The fuel puddling is seen very easily in EFI systems with datalogging. In fact, the best systems use OEM-style "wall-wetting" transient algorithms to account for the dynamic conditions that affect addition to and subtraction from the "puddle."
Could you expound on this a bit? PM if necessary.
Sure thing. When you look at transients, you can see that the commanded fueling (pulse width, duty cycle) does not match the amount of fuel getting into the cylinders based on the AFR. This is easily seen in fast transients because it takes time for the "puddle" to equilibrate but it is happening all the time as engine conditions change. The very basic way to see this is turn off any acceleration enrichment and decceleration fuel cuts, and stab the throttle on vehicle with a well-tuned fueling table, and you will see the AFR go lean on throttle opening and rich on throttle closing. The fuel table is commanding the correct steady-state fueling for the conditions, so what gives? The answer is that there is a change in the amount of fuel puddling relative to what is going into the cylinder, including the fuel being injected and the fuel evaporating out of the puddle.
The obvious reasons the amount adding to the puddle and the amount evaporating from the puddle would change are things like fuel flow, temperature (wall and air), pressure, air velocity (engine speed) and turbulence, things like that. So the more advanced strategies don't only measure the amount of fuel addition necessary under acceleration (think of a carburetor pump shot) to maintain steady AFR and prevent any stumble, they keep track of the size of the puddle under different conditions, as well as how transient conditions will add to or remove from the puddle.
The megasquirt guys actually have really good writeups on this - Google search for "x-tau" and "enhanced acceleration enrichment." In all honesty, I generally find that the carb pump shot strategy along with decel fuel cuts work great. I'm not trying to make emissions on any of my cars!
I just thought it pertinent to mention that, to my knowledge, all modern port fuel injected vehicles use some type of strategy like this to take the fuel puddling into account to keep AFRs steady during transients. So if the OEMs are doing it on highly tuned systems, that indicates to me that there is no getting away from puddling!
I never imagined that!
I'm currently using MS3x, so I'll play with the x-tau and EAE.
Excellent explanation.
Back on topic- sorry.
He who is in me is greater than he who is in the world.
There are a few guides out there, but nothing really definitive. I've played with it a bit, but it is difficult to get my head around which curves to move. The VE table has to be dead nuts (within a few percent) to even enable it or you'll end up with a mess, I know that much!
I also run MS3X...
Okay, NOW back on topic.
Mike Gallo, President
Protohawk - Design/Prototyping, Small Project Support, and Contract Manufacturing
CCA Racing Products - Torque Plates and Engine Rebuild Tooling
I know people on other forums want to debate, more like argue, that the burr finish changes CSA is some drastic way. I don't find that.. And if you believe in the finish your sized correctly because it's how your going to do it!
I do each and every manifold in burr finish. Intake runners it depends on the head and application.
I have lost flow hand finishing my own CNC heads. I send my ports burr finished to be scanned for digitizing.
I know how I'm doing it and I have put a disclaimer on my site for those who don't like it. Reads something like we won't have a problem if you know what your getting and if you don't believe in it, don't order one....
cspeier wrote:I know people on other forums want to debate, more like argue, that the burr finish changes CSA is some drastic way. I don't find that.. And if you believe in the finish your sized correctly because it's how your going to do it!
I do each and every manifold in burr finish. Intake runners it depends on the head and application.
I have lost flow hand finishing my own CNC heads. I send my ports burr finished to be scanned for digitizing.
I know how I'm doing it and I have put a disclaimer on my site for those who don't like it. Reads something like we won't have a problem if you know what your getting and if you don't believe in it, don't order one....
I have tried many times to duplicate your finish. I just don't have the talent. My crap also loses flow when I burr finish it. I'd love to be able to do it.
I have tried many times to duplicate your finish. I just don't have the talent. My crap also loses flow when I burr finish it. I'd love to be able to do it.
i'm surprised some are saying they are losing Flow CFM rough-burr-finishing their Ports and/or Short Turn Curves ???
half the time i see no difference in Flow CFM
the other i gain Flow CFM
i have never lost Flow CFM with very rough or somewhat smooth burr-finish
... whats going on ????
possibly removing too much metal to create your burr-finish ???
changing the curve shape too far ???
I have tried many times to duplicate your finish. I just don't have the talent. My crap also loses flow when I burr finish it. I'd love to be able to do it.
i'm surprised some are saying they are losing Flow CFM rough-burr-finishing their Ports and/or Short Turn Curves ???
half the time i see no difference in Flow CFM
the other i gain Flow CFM
i have never lost Flow CFM with very rough or somewhat smooth burr-finish
... whats going on ????
possibly removing too much metal to create your burr-finish ???
changing the curve shape too far ???
I was just reading over your article again and saw this part, what is your take on the CS change or the thought that the engine thinks it's small change?
HRET:
Jim McFarland has been pushing this concept for as long as I’ve known him. I suspect the increased texturing is promoting better mixture quality due to less fuel separation and finer droplets that burn more efficiently. Improve mixture quality delivers the power increase and combined with the ever so slight port cross-section enlargement raises the rpm level of the power curve. You think?
LM:
My Dyno tests so far show around a maximum gain of .018% times Peak HP as the typical HP gain from a rough carbide finish everywhere including the Intake Manifold. The majority of the tests were with VP's Q-16 race gas, the rest of the tests were with VP C23, C25 , C16, and Exxon 93 premium. I agree with Jim McFarland; it appears to be trapping a greater amount of higher quality mixture by IVC point and also burning it more efficiently during combustion.
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
maxracesoftware wrote:...My Dyno tests so far show around a maximum gain of .018% times Peak HP as the typical HP gain from a rough carbide finish everywhere including the Intake Manifold. The majority of the tests were with VP's Q-16 race gas, the rest of the tests were with VP C23, C25 , C16, and Exxon 93 premium. I agree with Jim McFarland; it appears to be trapping a greater amount of higher quality mixture by IVC point and also burning it more efficiently during combustion.
Clearly some decimal slip here. This number would correspond to a less than two tenth of a horsepower gain for a 1,000 hp engine...
maxracesoftware wrote:...My Dyno tests so far show around a maximum gain of .018% times Peak HP as the typical HP gain from a rough carbide finish everywhere including the Intake Manifold. The majority of the tests were with VP's Q-16 race gas, the rest of the tests were with VP C23, C25 , C16, and Exxon 93 premium. I agree with Jim McFarland; it appears to be trapping a greater amount of higher quality mixture by IVC point and also burning it more efficiently during combustion.
Clearly some decimal slip here. This number would correspond to a less than two tenth of a horsepower gain for a 1,000 hp engine...
0.18 * 1300 HP = 23.4 HP gain
0.18 * 1400 HP = 25.2 HP gain
we now do pretty many 632 cid engines and larger to 854 cid so far
and those HP gains hold up
...same for all the other various size Engines i test this on .
i've done a ton of Dyno and Dragstrip testing since that old Article
and every engine so far picks up HP... not one has lost HP
I have tried many times to duplicate your finish. I just don't have the talent. My crap also loses flow when I burr finish it. I'd love to be able to do it.
i'm surprised some are saying they are losing Flow CFM rough-burr-finishing their Ports and/or Short Turn Curves ???
half the time i see no difference in Flow CFM
the other i gain Flow CFM
i have never lost Flow CFM with very rough or somewhat smooth burr-finish
... whats going on ????
possibly removing too much metal to create your burr-finish ???
changing the curve shape too far ???
I think I'm just not getting the finish correct. I've tried several burrs. I've changed speed. I tried different pressure. I just saw can't duplicate what you guys are doing. Wish I could.
Not trying to be dick here Larry, but decimals and % symbols do matter.
The quoted article says point zero one eight percent, which is less than 1/4 HP for a 1300 hp engine.
The above post says 0.18 times 1300, which is two hundred and thirty four hp.
I'm sure you mean 1.8 percent, or 23.4 hp for a 1300 hp engine.
Not trying to be dick here Larry, but decimals and % symbols do matter.
The quoted article says point zero one eight percent, which is less than 1/4 HP for a 1300 hp engine.
The above post says 0.18 times 1300, which is two hundred and thirty four hp.
I'm sure you mean 1.8 percent, or 23.4 hp for a 1300 hp engine.
Bill, thats OK
Stan Weiss jumps on me everytime i post a math percent mistake like that on my Forum
