v8 douchebags
05-22-2006, 11:18 AM
#212
3.0 BAR
Join Date: Dec 2002
Posts: 3,703
Re: v8 douchebags
Originally Posted by Moving_Target
RWD has the advantage of weight transfer from a dead stop.
Originally Posted by Moving_Target
I like ****.
I can't believe this is still going on....
I respect and like anything fast. 3 cyl to W12's, Diesels to rocket engines.
05-22-2006, 10:42 PM
#213
0.5 BAR
Join Date: May 2005
Posts: 65
Re: v8 douchebags
Dont' shoot me if i quote a little "Race Car Vehicle Dynamics" specifically from pgs. 730-733 (please excuse any spelling mistakes)
Front Wheel Drive
The current popularity of front-wheel drive in passenger cars might suggest that this drive concept is a relatively new one. This is hardly the case. Some historians point to the Cugnot steam carriage of 1770 as the first application of the front wheel drive system.
Walter Christie appears as the front-wheel drive pioneer (circa 1904-09). His race cars were powered by huge engines in various configurations with powers approaching 100 bhp. The slow-turning engines were located transversely such that the drive was taken directly off the two ends of the crankshaft through a flywheel/clutch and universal joint to each wheel. The clutches performed the differential function. The machines were used for record attempts in dirt track racing and in several road races. One of the machines is responsible for the term "plow" which is so frequently used to describe the limit understeer of FWD competition cars. Barney Oldfield driving a Christie in a dirt track competition literally "plowed" two wide ruts in the track as he accelerated out of a turn!
A number of front-wheel drive Millers competed at Indy in the period 1924--34 including two wins with 151 cu. in. engines and one with a 220 cu. in. engine of about 200bhp (1934) The cars were reported to have strong dropped throttle oversteer, and for this reason were consistantly more successful on the high-banked board tracks at steady high speeds.
In 1947-50 the Blue Crown Specials with 270 bhp Offy engines achieved three first and three seconds at Indy. These cars ran on hi-test aviation gasoline reducing pit stops when compared to alcohol-burning cars. They were light, reliable machines with some 65% of the weight on the front wheels. Since then no front-wheel drive car has won Indianapolis, nor have any appeared in the frist three places since 1950. The famous FWD Novi which appeared in 1946 was reported to produce over 500 bhp. Although it was extremely fast and established lap records, it suffered from tire wear , fuel consumption and handling problems. One fatal accident with this machine was apparently due to limit understeer.
The Saab FWD appeared in 1955, the first automotive product of the Swedish aircraft firm. It was to become popular for winter driving under low-coefficient conditions and perfomred extremely well in long-distance rallying with such drivers as Erik Carlsson using his hand brake technique for corner entry. Following the Saab, the English Mini has been very successful in rallying and also in small displacement sedan racing.
From this brief history of front-wheel-drive race cars the following conclusions may be drawn:
1. Front drive has been most successful in the lower power/weight range and in situations in which superior directional stability on low coefficients is important. There has never been a successful front-drive Grand Prix car nor a competitive Indianapolis car of more than 300 hp.
2. In straight-line acceleration, the load on the front wheels is reduced by the longitudinal load transfer. This leads to the use of static weight bias to control wheel spin at the lower speeds in the lower gears. The situation is aggravated in higher-powered, lighter vehicles and may require 60-70%(or more) of the static weight on the front wheels. A limited-slip differential may be desirable to control the lightly loaded wheel under combined cornering/acceleration (turn exit) but this may induce undesirable steering forces and generally interfere with control feedback to the driver. Some success is now found with the viscous type of limited slip.
3. Forward weight bias combined with tractive effort on the front tends to induce excessive understeer in the linear range, plow at the limit (at steady-state), and reduced max lateral. This is due to tire load sensitivity and friction circle effects and is most noticable on acceleration out of turns. The understeer/plow may be reduced by sitckier tires on the front and by taking some of the lateral load transfer on the rear The amount of LLTD on the rear is limited by lift of the inside rear wheel.
4. The forward weight bias is basically unfavorable to maximum braking because of tire load sensitivity losses due to unequal front and rear loading. The situation is improved if larger tires are used on front. Proportionally more rear brake ( or even lockup of the the rear tires) is one technique which has been used to get the tail out for promoting "turn-in" and rear slip angle for cornering. It has benn used in "trail braking" where the left foot is used to braking and the right foot remains on the throttle to keep the front wheel s from locking up.
5. Trim changes occur frequently in circuit racing, for example, if balked by another competitor in a turn. Dropped throttle tranfers load forward, increases the inward lateral force on the front wheels, and increases the size of the tire circle diagram on front. A destabliizing moment is created with a magnitude depending on the amount of engine motoring torque (note that with an automatic transmission, motoring torque at the wheels may be very small). If the vehicle is stable it will retrim without control action at a higher lateral acceleration. If near the limit it may spin out if not caught by control action. As Reid Railton pointed out, when a front drive is loose and near incipient spin the best treatment may be to ease on the throttle and transfer load aft, but "the relief is only temporary." Driving a high-powered front drive at the limit requires more judgement and experience, as the Novi history demonstrates.
In summary, it is more difficult to achive a neutral vehicle over the operating range with front-wheel drive than with rear- or four-wheel drive. The compromises required to achieve balance of handling and performance over a circuit are critical. The situation becomes progressively more difficult as power is increased.
FWD cars have appeared with a variety of engine/transmission arrangements, for example:
1.Longitudinal engine, behind differential.
2. Longitudinal engine, in front of differential
3. Longitudinal engine, above differential
4. Transverse engine, above transmission
5. Transverse engine, in line with transmission
The choice of any one type over another is a question of packaging and possibley wight distribution.
Front Wheel Drive
The current popularity of front-wheel drive in passenger cars might suggest that this drive concept is a relatively new one. This is hardly the case. Some historians point to the Cugnot steam carriage of 1770 as the first application of the front wheel drive system.
Walter Christie appears as the front-wheel drive pioneer (circa 1904-09). His race cars were powered by huge engines in various configurations with powers approaching 100 bhp. The slow-turning engines were located transversely such that the drive was taken directly off the two ends of the crankshaft through a flywheel/clutch and universal joint to each wheel. The clutches performed the differential function. The machines were used for record attempts in dirt track racing and in several road races. One of the machines is responsible for the term "plow" which is so frequently used to describe the limit understeer of FWD competition cars. Barney Oldfield driving a Christie in a dirt track competition literally "plowed" two wide ruts in the track as he accelerated out of a turn!
A number of front-wheel drive Millers competed at Indy in the period 1924--34 including two wins with 151 cu. in. engines and one with a 220 cu. in. engine of about 200bhp (1934) The cars were reported to have strong dropped throttle oversteer, and for this reason were consistantly more successful on the high-banked board tracks at steady high speeds.
In 1947-50 the Blue Crown Specials with 270 bhp Offy engines achieved three first and three seconds at Indy. These cars ran on hi-test aviation gasoline reducing pit stops when compared to alcohol-burning cars. They were light, reliable machines with some 65% of the weight on the front wheels. Since then no front-wheel drive car has won Indianapolis, nor have any appeared in the frist three places since 1950. The famous FWD Novi which appeared in 1946 was reported to produce over 500 bhp. Although it was extremely fast and established lap records, it suffered from tire wear , fuel consumption and handling problems. One fatal accident with this machine was apparently due to limit understeer.
The Saab FWD appeared in 1955, the first automotive product of the Swedish aircraft firm. It was to become popular for winter driving under low-coefficient conditions and perfomred extremely well in long-distance rallying with such drivers as Erik Carlsson using his hand brake technique for corner entry. Following the Saab, the English Mini has been very successful in rallying and also in small displacement sedan racing.
From this brief history of front-wheel-drive race cars the following conclusions may be drawn:
1. Front drive has been most successful in the lower power/weight range and in situations in which superior directional stability on low coefficients is important. There has never been a successful front-drive Grand Prix car nor a competitive Indianapolis car of more than 300 hp.
2. In straight-line acceleration, the load on the front wheels is reduced by the longitudinal load transfer. This leads to the use of static weight bias to control wheel spin at the lower speeds in the lower gears. The situation is aggravated in higher-powered, lighter vehicles and may require 60-70%(or more) of the static weight on the front wheels. A limited-slip differential may be desirable to control the lightly loaded wheel under combined cornering/acceleration (turn exit) but this may induce undesirable steering forces and generally interfere with control feedback to the driver. Some success is now found with the viscous type of limited slip.
3. Forward weight bias combined with tractive effort on the front tends to induce excessive understeer in the linear range, plow at the limit (at steady-state), and reduced max lateral. This is due to tire load sensitivity and friction circle effects and is most noticable on acceleration out of turns. The understeer/plow may be reduced by sitckier tires on the front and by taking some of the lateral load transfer on the rear The amount of LLTD on the rear is limited by lift of the inside rear wheel.
4. The forward weight bias is basically unfavorable to maximum braking because of tire load sensitivity losses due to unequal front and rear loading. The situation is improved if larger tires are used on front. Proportionally more rear brake ( or even lockup of the the rear tires) is one technique which has been used to get the tail out for promoting "turn-in" and rear slip angle for cornering. It has benn used in "trail braking" where the left foot is used to braking and the right foot remains on the throttle to keep the front wheel s from locking up.
5. Trim changes occur frequently in circuit racing, for example, if balked by another competitor in a turn. Dropped throttle tranfers load forward, increases the inward lateral force on the front wheels, and increases the size of the tire circle diagram on front. A destabliizing moment is created with a magnitude depending on the amount of engine motoring torque (note that with an automatic transmission, motoring torque at the wheels may be very small). If the vehicle is stable it will retrim without control action at a higher lateral acceleration. If near the limit it may spin out if not caught by control action. As Reid Railton pointed out, when a front drive is loose and near incipient spin the best treatment may be to ease on the throttle and transfer load aft, but "the relief is only temporary." Driving a high-powered front drive at the limit requires more judgement and experience, as the Novi history demonstrates.
In summary, it is more difficult to achive a neutral vehicle over the operating range with front-wheel drive than with rear- or four-wheel drive. The compromises required to achieve balance of handling and performance over a circuit are critical. The situation becomes progressively more difficult as power is increased.
FWD cars have appeared with a variety of engine/transmission arrangements, for example:
1.Longitudinal engine, behind differential.
2. Longitudinal engine, in front of differential
3. Longitudinal engine, above differential
4. Transverse engine, above transmission
5. Transverse engine, in line with transmission
The choice of any one type over another is a question of packaging and possibley wight distribution.
05-22-2006, 10:43 PM
#214
0.5 BAR
Join Date: May 2005
Posts: 65
Re: v8 douchebags
Rear-Wheel Drive
Rear-wheel drive is by far the most successful in racing. The combination of front-wheel steering and rear-wheel drive gives the driver control over both ends of the vehicle, by "steering with the throttle."
When compared with the front-wheel drive above, the rear drive is more compromised for control rather than stability.
With repect to high power, large tires can be fitted to a rear drive more easily (packaging FWD includes wheel clearance at steeing lock)
With dropped throttle trim change, the reaction to more front load is always destabilizing. With RWD the removal of road-load driving thrust increases the lateral force potential of the rear tires and is a stabilizing effect, opposing the destabilizing moment.
RWD cars are available with a variety of engine/transmission arrangements, for example:
1.Front-mounted longitudinal engine in unit with transmission and driveshaft to the rear.
2.Mid-mount longitudinal engine, otherwise above.
3.Forward-mounted longitudinal engine with engine-speed propshaft to rear-mounted transaxle.
4. Mid/rear transverse engine with unit-mounted transaxle
5. Mid-mounted longitudinal engine in unit with transaxle.
6. Rear-mounted longitudinal engine in unit with transaxle.
Rear-wheel drive is by far the most successful in racing. The combination of front-wheel steering and rear-wheel drive gives the driver control over both ends of the vehicle, by "steering with the throttle."
When compared with the front-wheel drive above, the rear drive is more compromised for control rather than stability.
With repect to high power, large tires can be fitted to a rear drive more easily (packaging FWD includes wheel clearance at steeing lock)
With dropped throttle trim change, the reaction to more front load is always destabilizing. With RWD the removal of road-load driving thrust increases the lateral force potential of the rear tires and is a stabilizing effect, opposing the destabilizing moment.
RWD cars are available with a variety of engine/transmission arrangements, for example:
1.Front-mounted longitudinal engine in unit with transmission and driveshaft to the rear.
2.Mid-mount longitudinal engine, otherwise above.
3.Forward-mounted longitudinal engine with engine-speed propshaft to rear-mounted transaxle.
4. Mid/rear transverse engine with unit-mounted transaxle
5. Mid-mounted longitudinal engine in unit with transaxle.
6. Rear-mounted longitudinal engine in unit with transaxle.
05-22-2006, 10:43 PM
#215
0.5 BAR
Join Date: May 2005
Posts: 65
Re: v8 douchebags
Four-Wheel Drive
Four-wheel-drive race vehicles have had the most success off-road and on low-coefficient surfaces, especially with very high power. A recent example of stage rallying and Pikes Peak by 4WD turbocharged cars.
On paved surfaces, 4WD has been less successful and some probbaly reasons are:
1. At all but the lowest speeds, modern race tires have been able to develop enough grip to eliminate wheel spin. In dragsters, 4WD was common for a brief time before the development of cars with rear weight bias (resulting in little tractive contribution from the front tires).
2.4WD adds a weight penalty and weight is extremely important, both for the obvious reason of power-to-weight ratio for acceleration and also tire load sensitivity.
3. With a fixed torque split (near 50% each end) 4WD , the car attitude cannot be changed easily with the throttle. This calls for special driving technique. Some 4WD Grand Prix cars have been built with variable torque split center differentials. In these cars the driver's tendency is to reduce the front wheel percentage as much as possible, at which pont the traction advantage of 4WD becomes questionable, even at low speed.
4WD cars have been built with front, mid and rear engines and a wide variety of transmission and final drives. The most successful seem to have been symmetrical front to rear in terms of weight distribution, suspension type, tire, etc.
The choice of differential type(s) grearly influentces the handling of 4WDs. For racing applications it has often been found that locking out the center differential gives the best results. Front differentials are limited to open or possibly the viscous limited-slip types to avoid steering problems. Rear differentials are often limited-slip types.
Four-wheel-drive race vehicles have had the most success off-road and on low-coefficient surfaces, especially with very high power. A recent example of stage rallying and Pikes Peak by 4WD turbocharged cars.
On paved surfaces, 4WD has been less successful and some probbaly reasons are:
1. At all but the lowest speeds, modern race tires have been able to develop enough grip to eliminate wheel spin. In dragsters, 4WD was common for a brief time before the development of cars with rear weight bias (resulting in little tractive contribution from the front tires).
2.4WD adds a weight penalty and weight is extremely important, both for the obvious reason of power-to-weight ratio for acceleration and also tire load sensitivity.
3. With a fixed torque split (near 50% each end) 4WD , the car attitude cannot be changed easily with the throttle. This calls for special driving technique. Some 4WD Grand Prix cars have been built with variable torque split center differentials. In these cars the driver's tendency is to reduce the front wheel percentage as much as possible, at which pont the traction advantage of 4WD becomes questionable, even at low speed.
4WD cars have been built with front, mid and rear engines and a wide variety of transmission and final drives. The most successful seem to have been symmetrical front to rear in terms of weight distribution, suspension type, tire, etc.
The choice of differential type(s) grearly influentces the handling of 4WDs. For racing applications it has often been found that locking out the center differential gives the best results. Front differentials are limited to open or possibly the viscous limited-slip types to avoid steering problems. Rear differentials are often limited-slip types.
05-22-2006, 10:46 PM
#216
0.5 BAR
Join Date: May 2005
Posts: 65
Re: v8 douchebags
Originally Posted by davcivic
AWD
I can't believe this is still going on....
I respect and like anything fast. 3 cyl to W12's, Diesels to rocket engines.
I can't believe this is still going on....
I respect and like anything fast. 3 cyl to W12's, Diesels to rocket engines.
I'm not bashing anyone's efforts (what gave anyone that idea??). I"m just posting a little tech. I applaud anyone that can take a $500 beater and throw stupid amounts of money at it to make it accelerate/brake/corner.
05-23-2006, 08:01 AM
#218
3.0 BAR
Join Date: Dec 2002
Posts: 3,703
Re: v8 douchebags
Originally Posted by Moving_Target
AWD if you're trying to launch on a table of marbles... :P
I'm not bashing anyone's efforts (what gave anyone that idea??). I"m just posting a little tech. I applaud anyone that can take a $500 beater and throw stupid amounts of money at it to make it accelerate/brake/corner.
I'm not bashing anyone's efforts (what gave anyone that idea??). I"m just posting a little tech. I applaud anyone that can take a $500 beater and throw stupid amounts of money at it to make it accelerate/brake/corner.
05-30-2006, 07:58 AM
#219
1.0 BAR
Join Date: Apr 2006
Posts: 600
Re: v8 douchebags
Are we talking Street-Legal power here? Iif so, If afraid an 8-cyl isnt exactly top of the line......Bugatti Veyron, Quad-Turbo W16...1001 whp, too bad they cost like $800,000 USD, cuz i think it would be some funny ---- if the same V8 douchebag 
s that have used the "My car has twice as many cylinders" line on anyone pushing a 4-banger Honda got a well-deserved Up-------- by one very Happy bugatti owner.javascript:void(0);
Grin
s that have used the "My car has twice as many cylinders" line on anyone pushing a 4-banger Honda got a well-deserved Up-------- by one very Happy bugatti owner.javascript:void(0);Grin
05-30-2006, 12:01 PM
#220
0.0 BAR
Join Date: Dec 2002
Posts: 0
Re: v8 douchebags
Originally Posted by ONDUHFLO
Are we talking Street-Legal power here? Iif so, If afraid an 8-cyl isnt exactly top of the line......Bugatti Veyron, Quad-Turbo W16...1001 whp, too bad they cost like $800,000 USD, cuz i think it would be some funny ---- if the same V8 douchebag s that have used the "My car has twice as many cylinders" line on anyone pushing a 4-banger Honda got a well-deserved Up-------- by one very Happy bugatti owner.javascript:void(0);
Grin
s that have used the "My car has twice as many cylinders" line on anyone pushing a 4-banger Honda got a well-deserved Up-------- by one very Happy bugatti owner.javascript:void(0);Grin
