DIY tunnel ram???

[SMITHBERGRACING]

Also goes from a larger radius to a tighter radius in the corners, has a 1.5° taper built into the runner but have the ability to manipulate it.

[Chipped tooth]

PM sent Smithberg

[nitro2]

Then I went to the event and got bit by the exhaust system and lost around 100 points with the huge torque dip we had because of exhaust system not being happy. We had an absolutely beautiful torque curve at home but at the event had a 60 ft/lb dip at 3400 rpm and another one of around 30-40 ft/lbs at 4500 or so. It ruined our score and negated any advantage we had with the intake manifold.

Certainly not the first time anyone has been bit by the UNOH exhaust system being different than the "home" exhaust system.

The IR runners work more like true IR if the bells are farther away from each other. Every runner is still "ringing" with large pressure pulses between IVC and IVO, so irregardless of the firing order, alternating pressure pulses at each bell affect every bell nearby. Lets say the alternating pressures between IVC and IVO are +/-4 psi, you can imagine the magnitude of the disturbance happening when rapidly applying + 4 psi or -4 psi at a cross sectional area like the base of the bell. Bearing in mind a flowbench only runs about 1 psi. and there is a pretty good "whoosh" from a flowbench for an area of that size. Its possible at some rpm level to make the close bell effect an advantage by having the right pulse at the right time, but that would be more beneficial for a narrow powerband application.

[wyrmrider]

Which is why we pointed the bells all kinds of funny ways and got kidded lots about them
I just smiled

[900HP]

Then I went to the event and got bit by the exhaust system and lost around 100 points with the huge torque dip we had because of exhaust system not being happy. We had an absolutely beautiful torque curve at home but at the event had a 60 ft/lb dip at 3400 rpm and another one of around 30-40 ft/lbs at 4500 or so. It ruined our score and negated any advantage we had with the intake manifold.

Certainly not the first time anyone has been bit by the UNOH exhaust system being different than the "home" exhaust system.

The IR runners work more like true IR if the bells are farther away from each other. Every runner is still "ringing" with large pressure pulses between IVC and IVO, so irregardless of the firing order, alternating pressure pulses at each bell affect every bell nearby. Lets say the alternating pressures between IVC and IVO are +/-4 psi, you can imagine the magnitude of the disturbance happening when rapidly applying + 4 psi or -4 psi at a cross sectional area like the base of the bell. Bearing in mind a flowbench only runs about 1 psi. and there is a pretty good "whoosh" from a flowbench for an area of that size. Its possible at some rpm level to make the close bell effect an advantage by having the right pulse at the right time, but that would be more beneficial for a narrow powerband application.

Clint, this is a graph of the very first pull we made with the carbon TR. The smaller curve is our very best pull with the 2nd best intake we had. The fuel corrections were maxxed out at +25% on this pull . We were able to improve on the shape of the torque curve dramatically over this but I don't have any photos. You can see a hint of the 3400 rpm dip here which turned into the 60 ft/lb crater at UNOH. Obviously there are some IR things going on as well but by the time we were done with it we had a very pretty curve.

first pull carbon tr.jpg

[MadBill]

... Every runner is still "ringing" with large pressure pulses between IVC and IVO...

Speaking of same, some years back I saw a story re a very highly-developed race engine that lost a whack of power when its (rounded corner rectangular) aluminum air bell/tubes were replaced with identically dimensioned very thin carbon fiber ones. Apparently the new ones were 'panting' under the influence of the pressure pulses, negatively affecting the tuning.

I'd expect round tubes to be less of an issue but it does give one pause, especially if using say silicon hose for part of the runner length..

[Kevin Johnson]

... some years back I saw a story re a very highly-developed race engine that lost a whack of power when its (rounded corner rectangular) aluminum air bell/tubes were replaced with identically dimensioned very thin carbon fiber ones. Apparently the new ones were 'panting' under the influence of the pressure pulses, negatively affecting the tuning.

I'd expect round tubes to be less of an issue but it does give one pause, especially if using say silicon hose for part of the runner length..

http://www.marineengineering.org.uk/page82.html

Causes of Secondary and Tertiary Structural stresses

Panting

. Caused by oscillatory motion on the shell plating at the Bow and Stern caused by the uneven water pressure as the vessel passes through waves. It is resisted by a system of Panting Beams, Panting Stringers, Breast Hook and a deep floor

Pounding or slamming

. Caused by bow pitching clear of the water then coming dow heavily on the sea. This is resisted by a reduction in framing pitch and possibly increased plate thickness

Local Loads

. These are due to such as deck Machinery, hull design etc

Vibration

. Localised stresses resisted by adjacent stresses are caused by vibrations from main engine, propellers etc

http://www.dsm.com/corporate/media/info ... ooler.html

To resist pulsation pressure loads or wall flexure -- panting.jpg

Vacuum hose usually has very stiff walls or internal braiding or reinforcement. Radiator hoses have had springs inserted within the hose enclosed volume but this would adversely affect air flow and not resist expansion of the hose.

http://www.siliconehose.com/4-ply-woven ... urbo-hose/