WHY? does my 911&914 rune better with 1/4 tank |
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WHY? does my 911&914 rune better with 1/4 tank |
yellow914 |
May 9 2008, 12:23 AM
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#1
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Member Group: Members Posts: 183 Joined: 28-March 08 From: San Jose, CA Member No.: 8,861 Region Association: Northern California |
I noticed when I had a 74 carrera 2.7 that at about 1/4 tank I'd get more H.P.'s and now that I have a 75 1.8 914 I get the same thing way better throttle response??? I doubt it's due to weight...any ideas?
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mightyohm |
May 9 2008, 12:45 AM
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#2
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Advanced Member Group: Benefactors Posts: 2,277 Joined: 16-January 03 From: Seattle, WA Member No.: 162 Region Association: Pacific Northwest |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump.
(IMG:style_emoticons/default/blink.gif) |
yellow914 |
May 9 2008, 12:50 AM
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#3
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Member Group: Members Posts: 183 Joined: 28-March 08 From: San Jose, CA Member No.: 8,861 Region Association: Northern California |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) Awesome!...it was driving me nuts....I noticed like a 20% plus increase! |
ericread |
May 9 2008, 03:04 AM
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#4
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/bs.gif) Sooooo, the gravitational pull of the fuel... I have posted some BS remarks before, but this tops the chart! Let's see now, gravitational pull of an object is directly proportional to it's mass. Therefore, the mass of the gasoline would be so significant as to exert it's gravitational pull over the Earth's gravity and other large objects... (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif) A very entertaining explanation, but it just doesn't hold water... er, gas. Let's see... A gallon of gas weighs about 6 pounds. So a 12 gallon tank would weigh about 72 pounds. For shits and giggles, let's say that the weight of a gallon of gasoline = about 0.45 Kilograms at 60 degrees F (temperature is actually an important variable here). Thus, you have a mass of about (72 pounds times .45) 32.4 Kilograms. So the 32.4 Kilograms of mass (the gasoline) is interacting with a significant gravitational force. Let's see, the other really big gravitational force is the Earth, which has a Mass of about 6,600,000,000,000,000,000,000 (6.6 sextillion) short tons (6.0 sextillion metric tons), or 6.0 × 1024 kg. So in a contest of gravitational forces between the Earth and the gas, the Earth clearly wins. In fact, if it were true that there was a significant gravitational pull of objects which have a minor mass, say like a 50 story building, then the gas would be pulled to the building rather than to the engine. In fact we would all be pulled to the building. Bummer. Nope. But it was fun to dissect. I haven't done this math in about 25 years, since I taught astronomy at a planetarium, so I may be off by a decimal point or so. But it really doesn't matter, the gravitational pull of non-significant objects (say, smaller than the moon) just don't have any measurable effect, and thus, doesn't asssit in your car's performance. Let's do this again sometime (IMG:style_emoticons/default/bye1.gif) |
zymurgist |
May 9 2008, 05:55 AM
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#5
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"Ace" Mechanic Group: Members Posts: 7,411 Joined: 9-June 05 From: Hagerstown, MD Member No.: 4,238 Region Association: None |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) Agreed. Any astronomer will tell you that the more the universe expands, the faster that expansion is occurring. Therefore one can conclude that the emptier the vessel, the faster it goes, so your fuel tank will reach maximum velocity just before yout engine is starved for fuel. |
SGB |
May 9 2008, 08:44 AM
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#6
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just visiting Group: Members Posts: 4,086 Joined: 8-March 03 From: Huntsville, AL Member No.: 404 Region Association: South East States |
(IMG:style_emoticons/default/av-943.gif)
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) Agreed. Any astronomer will tell you that the more the universe expands, the faster that expansion is occurring. Therefore one can conclude that the emptier the vessel, the faster it goes, so your fuel tank will reach maximum velocity just before yout engine is starved for fuel. (IMG:style_emoticons/default/chair.gif) |
ericread |
May 9 2008, 08:58 AM
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#7
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) Oh, I forgot to mention one other thing. Besides the gravitational pull thing, I need to mention the error in the statement "the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump". Everybody knows that you can't turbo a 914... (IMG:style_emoticons/default/laugh.gif) |
DNHunt |
May 9 2008, 09:15 AM
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#8
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914 Wizard? No way. I got too much to learn. Group: Members Posts: 4,099 Joined: 21-April 03 From: Gig Harbor, WA Member No.: 598 |
It seems to me it might have something to do with the choice of measuring instruments. Butt dynos are are notoriously inaccurate. It may be open for discussion but, my opinion is they may vary in the neighborhood of + or - 20%.
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purple |
May 9 2008, 09:51 AM
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#9
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Pigeon feeders attract me Group: Members Posts: 938 Joined: 24-July 07 From: Houston, TX Member No.: 7,942 Region Association: None |
Glad to see the sense of humor is still alive!
probably because gas weighs 8 pounds per gallon. less weight = more speed |
ericread |
May 9 2008, 10:00 AM
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#10
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
I absolutely love the term "tiny turbocharger inside your fuel pump"!!! It gives me visions of tiny exhaust pipes and wastegates! (IMG:style_emoticons/default/av-943.gif) Whatever it is, I want one!!! |
ConeDodger |
May 9 2008, 10:10 AM
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#11
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Apex killer! Group: Members Posts: 23,615 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California |
You know, Randall recently did an experiment with something like this. He found that the car was definately faster with fuel in it than without. Unfortunately so did the rest of us. (IMG:style_emoticons/default/mad.gif)
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ericread |
May 9 2008, 10:11 AM
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#12
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
You know, Randall recently did an experiment with something like this. He found that the car was definately faster with fuel in it than without. Unfortunately so did the rest of us. (IMG:style_emoticons/default/mad.gif) (IMG:style_emoticons/default/av-943.gif) |
brer |
May 9 2008, 10:17 AM
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#13
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Advanced Member Group: Members Posts: 2,555 Joined: 10-March 05 From: san diego Member No.: 3,736 Region Association: None |
Octane settles over time so when you get to the bottom of the tank you get all the juicy bits.
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ericread |
May 9 2008, 10:28 AM
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#14
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
Octane settles over time so when you get to the bottom of the tank you get all the juicy bits. I have optimized my tank so that I only feed my engine from fuel the bottom quarter of the tank. No matter how full the tank is, my engine only receives gas from the bottom quarter. This allows me to always access the juicy Octane bits. |
purple |
May 9 2008, 10:30 AM
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#15
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Pigeon feeders attract me Group: Members Posts: 938 Joined: 24-July 07 From: Houston, TX Member No.: 7,942 Region Association: None |
OMG NO WAY! I DID THAT TOO! We Rock!
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brer |
May 9 2008, 10:32 AM
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#16
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Advanced Member Group: Members Posts: 2,555 Joined: 10-March 05 From: san diego Member No.: 3,736 Region Association: None |
How did you do that?
If someone makes a kit I'm buying. |
Heeltoe914 |
May 9 2008, 10:35 AM
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#17
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Senior Member Group: Members Posts: 1,135 Joined: 31-January 06 From: Tujunga Calif, Member No.: 5,506 |
The gravitational pull of the fuel in the tank counteracts the torque of the engine when the tank is full. At less than half a tank, the effect is reversed. The net effect is that with a nearly empty tank, the fuel is actually accelerated into the engine, like a tiny turbocharger inside your fuel pump. (IMG:style_emoticons/default/blink.gif) Thats deep WOW. good info (IMG:style_emoticons/default/chair.gif) |
ericread |
May 9 2008, 10:44 AM
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#18
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The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
Let's face it. There are no quick fixes to milage or performance. You have to use the gas magments if you want significant increases.
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ConeDodger |
May 9 2008, 11:04 AM
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#19
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Apex killer! Group: Members Posts: 23,615 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California |
Let's face it. There are no quick fixes to mileage or performance. You have to use the gas magnets if you want significant increases. Word! (after I made a little spelling correction) I used one of those turbo devices in my intake once and my stocks went up by 70% I am now a believer. I religiously watch late night and day-time cable to find out the latest innovations. Billy Blanks is a God to me... I hear the latest is to rub pickle juice on your tires to get more miles out of them. It is an incredible use for something that goes to the sink in most cases. The tire companies don't want you to know that. In fact they will probably buy this website and shut it down to keep this information under wraps... (IMG:style_emoticons/default/av-943.gif) |
purple |
May 9 2008, 11:23 AM
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#20
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Pigeon feeders attract me Group: Members Posts: 938 Joined: 24-July 07 From: Houston, TX Member No.: 7,942 Region Association: None |
Let's face it. There are no quick fixes to mileage or performance. You have to use the gas magnets if you want significant increases. Word! (after I made a little spelling correction) I used one of those turbo devices in my intake once and my stocks went up by 70% I am now a believer. I religiously watch late night and day-time cable to find out the latest innovations. Billy Blanks is a God to me... I hear the latest is to rub pickle juice on your tires to get more miles out of them. It is an incredible use for something that goes to the sink in most cases. The tire companies don't want you to know that. In fact they will probably buy this website and shut it down to keep this information under wraps... (IMG:style_emoticons/default/av-943.gif) See, my previous owner stapled bacon to my tires before selling the car to me... sadly, all it does is make the tires slippery... I seriously want to change my forum name from purple to Bacon_Tires now. |
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