Drag newby, please help estimate 1/4 mile from 1/8 mile times
#16
Lexus Test Driver
Join Date: Jun 2006
Location: Hurricane Capital Of The World
Posts: 1,047
Likes: 0
Received 2 Likes
on
1 Post
Gernby, I went to the track tonight and I have to say that it's kinda hard to predict your 1/4 time. Here's the result of my best run.
r/t 60' 1/8 MPH 1/4 MPH
.000 2.058 8.875 81.47 13.606 101.98
I have no idea why my car has no top end tonight. Everything is the same, the only thing different is that I switched to 5W-20 instead or the old 5W-30 oil. From judging my 60' you would think i'll do at least 8.6x for 1/8 and my MPH for 1/4 should be at least 102. The result is kinda weird compare to all my other runs. My 60' usually in the 2.1x and I still hit 13.6 all day and tonight I hit my best 60' but I only run 13.6, so wierd.
r/t 60' 1/8 MPH 1/4 MPH
.000 2.058 8.875 81.47 13.606 101.98
I have no idea why my car has no top end tonight. Everything is the same, the only thing different is that I switched to 5W-20 instead or the old 5W-30 oil. From judging my 60' you would think i'll do at least 8.6x for 1/8 and my MPH for 1/4 should be at least 102. The result is kinda weird compare to all my other runs. My 60' usually in the 2.1x and I still hit 13.6 all day and tonight I hit my best 60' but I only run 13.6, so wierd.
#17
Gernby, I went to the track tonight and I have to say that it's kinda hard to predict your 1/4 time. Here's the result of my best run.
r/t 60' 1/8 MPH 1/4 MPH
.000 2.058 8.875 81.47 13.606 101.98
I have no idea why my car has no top end tonight. Everything is the same, the only thing different is that I switched to 5W-20 instead or the old 5W-30 oil. From judging my 60' you would think i'll do at least 8.6x for 1/8 and my MPH for 1/4 should be at least 102. The result is kinda weird compare to all my other runs. My 60' usually in the 2.1x and I still hit 13.6 all day and tonight I hit my best 60' but I only run 13.6, so wierd.
r/t 60' 1/8 MPH 1/4 MPH
.000 2.058 8.875 81.47 13.606 101.98
I have no idea why my car has no top end tonight. Everything is the same, the only thing different is that I switched to 5W-20 instead or the old 5W-30 oil. From judging my 60' you would think i'll do at least 8.6x for 1/8 and my MPH for 1/4 should be at least 102. The result is kinda weird compare to all my other runs. My 60' usually in the 2.1x and I still hit 13.6 all day and tonight I hit my best 60' but I only run 13.6, so wierd.
#20
Lexus Test Driver
Join Date: Jun 2006
Location: Hurricane Capital Of The World
Posts: 1,047
Likes: 0
Received 2 Likes
on
1 Post
I have the Joez and yes I ran 13.49 without the intake, it was such a big disappoinment last night. BTW this was done on the stock dunlop with 17k miles, I guess the Dunlop isn't that bad at all.
#23
11 Second Club
iTrader: (2)
Pressure, Temperture and Humidity
I came across an article that explained these 3 variables and thought I would share it with the rest of you. Pretty shocking if I must say so myself. Would never expect that Barometric pressure is the #1 key to fast times. So watch those pressures before hitting the track!
"barometric pressure is number one by a wide margin, temperature is second, and humidity is a distant third.
Barometric pressure is the key to fast times. Barometric pressure is Mother Nature's supercharger; it's the force that pushes air and fuel into the cylinders to fill the low-pressure area created by the downward motion of the pistons. You've undoubtedly heard that Nature abhors a vacuum. Well, it's barometric pressure that fills the void.
If you race on a day with 24 inches of barometric pressure, 60-degree air temperature, and zero humidity, two of the three factors would be perfect - but your race car would still be slow. On the other hand, if the barometer were 32 inches, your car would be incredibly fast even in 90-degree heat and 70 percent humidity.
Engine performance essentially comes down to the number of oxygen molecules that you can pack into the cylinder on each combustion cycle. Barometric pressure does the packing for you. We can also increase the effective pressure by using a hood scoop's ram effect to "supercharge" the air box; it's an effect that can't be duplicated on most engine dynos.
Air temperature, in tandem with barometric pressure, has a direct bearing on air density. Warm air is less dense than cool air and consequently contains fewer oxygen molecules in a given volume. That's why we want our engines to breathe cool air through a scoop rather than heated air from beneath the hood. Temperature does matter: Horsepower increases approximately 1 percent for every 10-degree Fahrenheit reduction in temperature. Savvy racers know that their cars run faster in the cooler air of the late rounds even though the barometer doesn't change significantly.
FULL ARTICLE
"barometric pressure is number one by a wide margin, temperature is second, and humidity is a distant third.
Barometric pressure is the key to fast times. Barometric pressure is Mother Nature's supercharger; it's the force that pushes air and fuel into the cylinders to fill the low-pressure area created by the downward motion of the pistons. You've undoubtedly heard that Nature abhors a vacuum. Well, it's barometric pressure that fills the void.
If you race on a day with 24 inches of barometric pressure, 60-degree air temperature, and zero humidity, two of the three factors would be perfect - but your race car would still be slow. On the other hand, if the barometer were 32 inches, your car would be incredibly fast even in 90-degree heat and 70 percent humidity.
Engine performance essentially comes down to the number of oxygen molecules that you can pack into the cylinder on each combustion cycle. Barometric pressure does the packing for you. We can also increase the effective pressure by using a hood scoop's ram effect to "supercharge" the air box; it's an effect that can't be duplicated on most engine dynos.
Air temperature, in tandem with barometric pressure, has a direct bearing on air density. Warm air is less dense than cool air and consequently contains fewer oxygen molecules in a given volume. That's why we want our engines to breathe cool air through a scoop rather than heated air from beneath the hood. Temperature does matter: Horsepower increases approximately 1 percent for every 10-degree Fahrenheit reduction in temperature. Savvy racers know that their cars run faster in the cooler air of the late rounds even though the barometer doesn't change significantly.
FULL ARTICLE
Last edited by caymandive; 02-01-07 at 08:45 AM.
#25
Super Moderator
Not too long ago I bought my track here in Mexico one of these devices. Actually has a little external sensor, too.
Now, I race at a very high altitude, 7,411 feet at the starting line, but every day when I arrive I check this device to gauge if it is a decent night or not and we let the racers know. A lot of them would moan about times, but this actually reassured them when they realized the heavens above aren't always on our side.
My best nights actually come when we have a low bank of clouds in the area and things get really cool, high pressure, low humidity and low temperatures.
Now, I race at a very high altitude, 7,411 feet at the starting line, but every day when I arrive I check this device to gauge if it is a decent night or not and we let the racers know. A lot of them would moan about times, but this actually reassured them when they realized the heavens above aren't always on our side.
My best nights actually come when we have a low bank of clouds in the area and things get really cool, high pressure, low humidity and low temperatures.
#26
11 Second Club
iTrader: (2)
Not too long ago I bought my track here in Mexico one of these devices. Actually has a little external sensor, too.
Now, I race at a very high altitude, 7,411 feet at the starting line, but every day when I arrive I check this device to gauge if it is a decent night or not and we let the racers know. A lot of them would moan about times, but this actually reassured them when they realized the heavens above aren't always on our side.
My best nights actually come when we have a low bank of clouds in the area and things get really cool, high pressure, low humidity and low temperatures.
Now, I race at a very high altitude, 7,411 feet at the starting line, but every day when I arrive I check this device to gauge if it is a decent night or not and we let the racers know. A lot of them would moan about times, but this actually reassured them when they realized the heavens above aren't always on our side.
My best nights actually come when we have a low bank of clouds in the area and things get really cool, high pressure, low humidity and low temperatures.
#27
Just an FYI to let you guys know that I went out to the 1/4 mile track yesterday, and started a new thread about it here. FWIW, my prediction in the 1st post above was pretty close since I got a 13.251 @ 105.34.
Using diff between 1/4 and 1/8: 13.211 - 13.304 sec
Using diff between trap speeds: 104.07 - 105.04 mph
Using diff between trap speeds: 104.07 - 105.04 mph
#28
Lead Lap
Join Date: May 2006
Location: Ottawa,Ontario
Posts: 688
Likes: 0
Received 0 Likes
on
0 Posts
Can't we let our hoods partially open from the interior latch and let the manual hood release hold it. This would cause a ram effect strait to the air inlet. Anyone tried? Is this dangerous of the hood releasing? I heard in the past some Porche guys did this to overcome their engine over heating.
#29
Can't we let our hoods partially open from the interior latch and let the manual hood release hold it. This would cause a ram effect strait to the air inlet. Anyone tried? Is this dangerous of the hood releasing? I heard in the past some Porche guys did this to overcome their engine over heating.
The Porsche guys were doing something totally different. They were air cooled rear engines. They were probably just altering the hinges of their engine cover to channel more air down across the block.
#30
Lead Lap
Join Date: May 2006
Location: Ottawa,Ontario
Posts: 688
Likes: 0
Received 0 Likes
on
0 Posts
I see. Here is another crazy idea then. To rap your JoeZ pipe in some sort of heat insulator. I know the metal vs plastic inlet pipe has been discussed before. But some sort of fiberglass insulator sure couldn't hurt. Even if it's just when your engine is idling on the line and producing allot of heat. It would prevent the pipe to get to hot and in return get cooled quicker after take off. Right?
I see you guys removing your engine covers. Is this only to allow the cool down of the engines between runs? According to Lexus these are for proper air flow in the engine compartment. Notice any difference with it on/off for you run?
I see you guys removing your engine covers. Is this only to allow the cool down of the engines between runs? According to Lexus these are for proper air flow in the engine compartment. Notice any difference with it on/off for you run?