Post Your 1/4 Times And Mods.


doom... I think ure operating at a level most people don't understand.... can u elaborate what constitutes DA and how big of an impact it can have on Ets? some people think it can add 70 Hp to their bike...…… is this misleading? I look forward to ure response... and I think most men are afraid to ask because it makes them look stupid... thankfully I was born without this gene, as u must know by now.
OK, I'll give it a shot. Our engines burn an air/fuel mixture. The more air (oxygen) you can get into a cylinder, the more power you can potentially make. Turbos can force in more air = more power. The air we breath is roughly 20.9% oxygen by weight. Nitrous Oxide (N20) is 33% oxygen. More oxygen means you can burn more fuel = more power. Still with me? OK, when your intake valve opens the piston doesn't suck air into the cylinder, atmospheric pressure forces air into the engine. At sea level, gravity's effect on our atmosphere exhibits 14.7 lbs per square inch of pressure. The higher you are, less air is pushing down so that number gets smaller. Gravity also has its effects. The further away you are from the center of mass, the less force it applies. On an accurate scale, you would weigh less at Jake's house that you would at mine.

Elevation is simple. It's a distance relative to sea level. My home in Florida is 11 feet above sea level, Jake lives 5300 feet above sea level. Bad Water basen in Death Valley California is 280 feet below sea level.

Density altitude by definition is air density given as a height above mean sea level. Several things effect air density. Temperature, barometric pressure/altitude and humidity. Cool air is denser than hot air so cool air is heavier = lower DA. Higher barometer = lower DA. Humidity doesn't effect the numbers as much as tempature and pressure but it needs to be included. High humidity = higher DA. In summary, air = power potential. Lower DA = higher power.

How much does DA effect performance in drag racing ? A bunch! Super Comp races on an 8.90 second index everywhere... Except Jake's home track Bandimere Speedway where the ridiculous elevation slows the index class down to a 9.50. And six tenths is a bunch...
 
OK, I'll give it a shot. Our engines burn an air/fuel mixture. The more air (oxygen) you can get into a cylinder, the more power you can potentially make. Turbos can force in more air = more power. The air we breath is roughly 20.9% oxygen by weight. Nitrous Oxide (N20) is 33% oxygen. More oxygen means you can burn more fuel = more power. Still with me? OK, when your intake valve opens the piston doesn't suck air into the cylinder, atmospheric pressure forces air into the engine. At sea level, gravity's effect on our atmosphere exhibits 14.7 lbs per square inch of pressure. The higher you are, less air is pushing down so that number gets smaller. Gravity also has its effects. The further away you are from the center of mass, the less force it applies. On an accurate scale, you would weigh less at Jake's house that you would at mine.

Elevation is simple. It's a distance relative to sea level. My home in Florida is 11 feet above sea level, Jake lives 5300 feet above sea level. Bad Water basen in Death Valley California is 280 feet below sea level.

Density altitude by definition is air density given as a height above mean sea level. Several things effect air density. Temperature, barometric pressure/altitude and humidity. Cool air is denser than hot air so cool air is heavier = lower DA. Higher barometer = lower DA. Humidity doesn't effect the numbers as much as tempature and pressure but it needs to be included. High humidity = higher DA. In summary, air = power potential. Lower DA = higher power.

How much does DA effect performance in drag racing ? A bunch! Super Comp races on an 8.90 second index everywhere... Except Jake's home track Bandimere Speedway where the ridiculous elevation slows the index class down to a 9.50. And six tenths is a bunch...
if we are dealing with forced induction... is the effect as great as that as on a naturally aspirated motor? 14.7 lbs per square inch of pressure AT sea level... this number seems very important... do we have a way of working with this number to figure out losses? D/A... elevation/ temp/ barometric pressure..... all affect THAT NUMBER 14.7..... or did I miss something....
 
if we are dealing with forced induction... is the effect as great as that as on a naturally aspirated motor? 14.7 lbs per square inch of pressure AT sea level... this number seems very important... do we have a way of working with this number to figure out losses? D/A... elevation/ temp/ barometric pressure..... all affect THAT NUMBER 14.7..... or did I miss something....
That is the point of why we use DA. Lower DA=better performance. A DA of 0 means you are at standard temperature, pressure, and water. A DA of 5000 means you are at the equivalent of 5000 feet of elevation at standard temperature and water. DA tries to roll up the variables and make one comparable number out of all of them. Bottom line, you can forget the 14.7 and just use DA if you like. I find that water is the worst way to lose DA. I prefer the heat instead of the water so DA isn't perfect.
 
Yes I still can bench over 500 best ever was 540
update Doug Witt pro st rider rode my bike at MDIR race last weekend, and he is 180lbs, no set up change in bike so clutch and shock were set up for me not him, and with a shitty 60 ft due to wheelie 1.30 in 60 ft UGH bike still went 8.16 at 167mph ON ALL MOTOR Doug said that if we set shock and clutch for him the 60 fts should be 1.20 etc. if that is case that is a possible 7.80
this can be a great grudge or bracket bike as its not all cut up, also Bob Carpenter will tell you, lower compression and street ride this baby, he has several doing it now and they still make 250 plus RWHP and TQ you cant believe I will post time slip of Doug's Run Brett View attachment 542121
You can get away with riding a stroker motor on the street as long as the compression is not way high. I was thinking of doing a 1507 stroker street strip wih 13.1,
i was gonna call bob and ask him his thoughts but you already have proved its good to go.
 

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