Something Failed, let’s find it! Transmission Analysis.

[Bob R]

I always thought you wanted as smooth as flow as possible to the cylinder but once in the cylinder that is where the turbulence is needed in order to get a good burn. Smooth air in is one reason why I had some velocity stacks turned for my Rocket, getting the airflow smooth into the throttle bodies.

bob

 

[Claviger]

That's pretty poor.

Should look more like this.

Even the above leaves room for improvement, and it's not about being shinny, it's shape and contours.
Look at how the light travels along the port.
If this was a road and you were hitting these contours at 100+ MPH, how smooth would your exit be ?
One thing that I did when I was porting my Trident Head was to hold it up with the Combustion Chamber pointing to the Sun.
The light then traveled down the port and I could see the exact shape of that port.

This was the first "head that I had ported.
I did the R/H port and thought that was O.K.
I then moved onto the Center port, this I did better than the first one, so went back and did the first one again.
This was now better than the second one, so re did that !
Now onto the third port ...... I think I did about 11 ports on that 3 cylinder head.
I then built a simple flow bench and checked it there ..... more tweaking .............

Oh, my "Tutor" at the time was an Ex Mechanic specializing in cylinder Head work from the Old BRM Racing Business in the U.K (Well retired)

Also, I've broken a few bits along the way .....

I like the finish in yours, not mirrored but not rough cut, and I completely agree with all of your points. Also agree the carp head is shockingly roughly finished, just not sure it matters.

What WOULD be interesting is if the finish in it is responsible for the torque dip visible on all 265 kit bikes at or around 4500 RPM.

 

[Claviger]

That’s true bob, but a smooth finish doesn’t necessarily mean the smoothest flow.

 

[Claviger]

I would posit that a head with a rough finish but correct chokepoint to valve size/lift ratio will outperform any texture with incorrect ratios.

Bigger and smoother don’t mean more power. Except in the world of turbos and superchargers where bigger is almost always better.

Anyway all this stuff is what makes and breaks tuning shops, racers, etc. It’s a dark art and all I know for sure is the carp head isn’t a restriction at my power level, other things are like air filters, cams, and for sure the throttle bodies.

I know for a fact that good stacks will boost torque under peak without a meaningful loss at peak power, as I have the sheet to prove it.

That said the next two points to improve would be secondary shaft removal and boring the TBs with a proper taper and larger average diameter to speed air velocity and stack more air in during overlap. Paired with a longer duration cam there would certainly be more power had.

PS: I’m not after any more at this point from NA work, not interested in small incremental gains. When I’m ready for more it’ll be of the TTS kind.

 

[Paul Bryant]

The interesting thing about "Polished Ports" as it was described to me is, get a sheet of glass and a sheet of sand paper.
Pour a little petrol on both, then blow across it.
The Petrol on the glass will smear and not evaporate, just as the Guy was saying about the rain drops over the car bonnet.
Alternatively, blow the petrol on the sand paper, it will evaporate and disappear.

What I have done in the past after I have what "I think" is the correct shape of the port, is to then polish it to a mirror finish.
I then ran it through my home made flow bench and got figures.
With the finish of the port ANY irregularities are shown up when the Sun shines down them. (try it )

When I'm satisfied with the port, I bead blast it and roughen it up.

Oh, and Rob, that was just a photo of a port, not the ones in my Bike. It's completely stock.... kind of.

 

[Claviger]

The really interesting part is when you start talking differential surfaces based on injector spray pattern and direction. I've seen some ports where the roof is a perfect mirror, the sides a moderate polish and floor fairly rough, and they made ridiculous power out of the motors. Smoke and mirrors to distract from other secret modifications or a direct cause and effect, no idea, but it sure looked like it took a hell of a lot of work!!

Back to transmissions, I've been reading a bit and I think I've found a trick I'm going to try out to strengthen everything, further harden the exterior of the parts, removes the stress concentrations, and give them superior oil retaining ability. Waiting on a quote to disclose more, but it should be attainable and add some extra insurance for the future.

 

[Claviger]

I'm putting together my required parts list. Question about bolts that "must" be replaced. The crank ladder bolts, #2 on the fiche and part number T1160351, in the manual it says remove and collect the bolts. In other areas it specifically says "remove and discard" the bolts.

So, then, the 8 Crank ladder bolts are to be reused?

Just want to make sure I'm not skipping any bolts that must be replaced.

 

[Claviger]

Moved to First Page

 

[barbagris]

What I've come up with so far,

Full disclosure documentation - PRICELESS. Head porting - I really don't have the experience though I did know that polished ports are "bad". But I have never seen that Golf-Ball finish and my gut says "Do It".

ime - the first rule of engineering always runs true. If something LOOKS right then it probably is.

When I’m ready for more it’ll be of the TTS kind.

Ah Son of Millennium Falcon.

I've been reading a bit and I think I've found a trick I'm going to try out to strengthen everything, further harden the exterior of the parts, removes the stress concentrations, and give them superior oil retaining ability. Waiting on a quote to disclose more, but it should be attainable and add some extra insurance for the future.

There goes the Panigale!

 

[Ishrub]

Dimples on a golf ball create a thin turbulent boundary layer of air that clings to theball's surface. This allows the smoothly flowing air to follow the ball's surface a little farther around the back side of the ball, thereby decreasing the size of the wake.