1/4 mile questions
04-17-14, 05:39 PM
#1
1/4 mile questions
So I have never taken my car to a track so I'm a noob when it comes to 1/4 mile racing at the track.
Why is it that it seems that our cars need just about 500whp to get mid/low 12's in the 1/4 mile? That's almost 650hp at the crank! Where an off the showroom floor C63 Benz can do this all day bone stock with under 500hp at the crank. Is it traction issues with our cars? Is it our transmissions? I mean, even the ISF with 416hp at the crank can churn out high 12's bone stock.
What's the deal? I'd like to understand this.
Why is it that it seems that our cars need just about 500whp to get mid/low 12's in the 1/4 mile? That's almost 650hp at the crank! Where an off the showroom floor C63 Benz can do this all day bone stock with under 500hp at the crank. Is it traction issues with our cars? Is it our transmissions? I mean, even the ISF with 416hp at the crank can churn out high 12's bone stock.
What's the deal? I'd like to understand this.
04-27-14, 06:48 PM
#7
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21% drive train loss according to a Mustang dyno (my '98 GS400) and 3680lbs dry weight (+ / -) . Mine still does 0-60mph in under 6 seconds, but I'm thinking at the top end, the mass and tranny loss does sap too much power. Oh, don't forget, the GS400 loves to change gears very ... gingerly. That itself is a hard /fixed amount of delay that probably adds a good bit of time.
On the other hand, newer cars do have 6-7 spd transmissions so the ratios, shifting, etc. all factor in as well to make them use their power more efficiently, even if they ARE just as much pigs in the weight department.
On the other hand, newer cars do have 6-7 spd transmissions so the ratios, shifting, etc. all factor in as well to make them use their power more efficiently, even if they ARE just as much pigs in the weight department.
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04-27-14, 09:33 PM
#8
Weight. These cars are very heavy and for racing, it's all about the hp:weight ratio. Why do you think everyone who has a "track" car runs without full interior? Because the more weight you have, the slower it will be and the more power you'll need to get it to move. Make sense?
04-28-14, 03:45 PM
#10
We say flogging because, with a 416-horse, 5.0-liter V-8, an eight-speed auto that can shift gears in as little as 0.1 second, and a sport-tuned suspension, the IS F won't be driven like any other Lexus. The F's 2UR-GSE engine, based on the LS 600h L's 2UR-FSE V-8, utilizes unique aluminum cylinder heads (from Yamaha) as well as titanium intake valves, a water-cooled oil cooler, and a head scavenge oil pump, all devised for better high-speed and high-load driving. And, as we discovered at the test track, where the IS F recorded 0 to 60 mph in 4.3 seconds, the quarter mile in 12.7 at 112.3 mph, and 0.90g lateral acceleration, those three high-tech features weren't installed just for show. Same goes for the Brembo brake system, whose drilled and vented rotors (14.2 inches front/13.6 inches rear) and monoblock calipers (six-piston front/two-piston rear) halted the 3806-pound F from 60 mph in just 112 feet.
04-28-14, 09:07 PM
#11
Yup. So the weight is similar but it seems the major component here is the tranny. But is it possible that this could shave almost 1 full second on the 1/4 mile?! Figuring a stock 300hp GS400 can do the 1/4 mile in 14.2 and add 115hp (@ crank) you'll probably run 13.5/13.6. I knew tranny makes a difference but can't believe that much of a difference.
04-29-14, 01:39 PM
#12
I personally would love the own a "F''.. these numbers are quite impressive IMO
We say flogging because, with a 416-horse, 5.0-liter V-8, an eight-speed auto that can shift gears in as little as 0.1 second, and a sport-tuned suspension, the IS F won't be driven like any other Lexus. The F's 2UR-GSE engine, based on the LS 600h L's 2UR-FSE V-8, utilizes unique aluminum cylinder heads (from Yamaha) as well as titanium intake valves, a water-cooled oil cooler, and a head scavenge oil pump, all devised for better high-speed and high-load driving. And, as we discovered at the test track, where the IS F recorded 0 to 60 mph in 4.3 seconds, the quarter mile in 12.7 at 112.3 mph, and 0.90g lateral acceleration, those three high-tech features weren't installed just for show. Same goes for the Brembo brake system, whose drilled and vented rotors (14.2 inches front/13.6 inches rear) and monoblock calipers (six-piston front/two-piston rear) halted the 3806-pound F from 60 mph in just 112 feet.
We say flogging because, with a 416-horse, 5.0-liter V-8, an eight-speed auto that can shift gears in as little as 0.1 second, and a sport-tuned suspension, the IS F won't be driven like any other Lexus. The F's 2UR-GSE engine, based on the LS 600h L's 2UR-FSE V-8, utilizes unique aluminum cylinder heads (from Yamaha) as well as titanium intake valves, a water-cooled oil cooler, and a head scavenge oil pump, all devised for better high-speed and high-load driving. And, as we discovered at the test track, where the IS F recorded 0 to 60 mph in 4.3 seconds, the quarter mile in 12.7 at 112.3 mph, and 0.90g lateral acceleration, those three high-tech features weren't installed just for show. Same goes for the Brembo brake system, whose drilled and vented rotors (14.2 inches front/13.6 inches rear) and monoblock calipers (six-piston front/two-piston rear) halted the 3806-pound F from 60 mph in just 112 feet.
However, to make us all feel better about what we have...
(Taken from www.fantasycars.com)
In the olden days performance was not the first word that came to mind when thinking of Lexus. Now, the 1998 Motor Trend Import Car of the Year GS400 packs a 4.0-litre four-valves-per-cylinder 300 horsepower engine with VVT-i (variable valve timing) and accelerates to 60 mph in under 6 seconds. That kind of performance is enough to make more expensive competitors such as the Cadillac Seville STS and Mercedes E430 run for cover. Best of all, the V8 is silky smooth and perfectly refined. Linked to it is the five-speed automatic transmission that also allows you to shift progressively through the gears by using steering wheel mounted buttons.
Using the optional 235/45ZR17 Bridgestone Potenza RE030 tires mounted on 17 inch alloy rims, the aptitude of the handling and braking manage to surpass even that of the engine. While the ride is slightly firmer than on the smaller diameter rims and the steering is a little light for sporting tastes, the GS400 still manages out-brake both Porsche Boxsters and Ferrari F355s and run through the slalom in a Camaro Z28 pounding 67 mph. On the inside, a roomy cabin equipped with leather clad seats, real wood, an excellent sound system with glove box-mounted CD changer and superb ergonomics and isolation seal the package. True, the styling might not be for everyone, however with a lowest-in-class $45K base price and awesome performance with no compromise for luxury, this Lexus proves to be an unbeatable deal. - by Traian Popescu
Specifications:
Base Price, USD
44,800
Engine Type
DOHC 32-valve 90º V8
Powertrain Layout
Front engine, RWD
Displacement, cc
3971
Horsepower@rpm
300@6000
Torque, lb-ft@rpm
315@4000
Curb Weight, lb
3690
0-60 mph, sec
5.8
1/4 mile, sec@mph
14.3@98.9
600 ft slalom, mph
66.9
60-0 mph, ft
112
Top speed, mph
150
So 16 years later, our gs' still have the same braking performance as a brand new $60,000+ performance sedan with Brembo brakes.....
But agreeing with what everybody else has said already, it's the transmission. All I can think is how much the car changes with a 3.76 LSD and higher stall converter. Weight does play a part ( I believe every 50 lbs removed equals .1 second quicker in 1/4 mile ) So theoretically if you took out 500 lbs out of the car, it would run 1 second quicker in 1/4 with no "modifications"
04-29-14, 03:48 PM
#13
Correct! And if it's "unsparing" weight such as rotational mass it's a little more than double the effect!
For example with my car. I have nice forged 2-piece wheels but they are still very heavy for 19" wheels. Then I have one of the heaviest tires around Bridgestone Potenza Sports (but they never bent my wheels when I hit potholes-good sidewall reinforcement. These combined weigh in at almost 62lbs per rear wheel/tire setup! Now, say I would buy 19" Forgestar F14s for example, they only weigh 21lbs plus add a lightweight good tire like the Mich PS2 that is another 24lbs...all will be a total of 45lbs. Is save almost 17lbs in each rear setup and probably around 14lbs (staggered setup) each front setup. A total unsprung weight savings of over 60lbs! This equates to approx .3 sec off the 1/4 just like that. Plus since we're talking unsprung weight your steering and breaking will be greatly enhanced! I was really thinking about doing this for a while but just decided to throw more power at her. Lolol
Just examples of how little things can make a big difference. Swap out the hood and or trunk to CF, relocate battery to trunk, get a lightweight driveshaft and drive axles (both also unsprung items). You get the idea. But it does cost money though...unfortunately.
For example with my car. I have nice forged 2-piece wheels but they are still very heavy for 19" wheels. Then I have one of the heaviest tires around Bridgestone Potenza Sports (but they never bent my wheels when I hit potholes-good sidewall reinforcement. These combined weigh in at almost 62lbs per rear wheel/tire setup! Now, say I would buy 19" Forgestar F14s for example, they only weigh 21lbs plus add a lightweight good tire like the Mich PS2 that is another 24lbs...all will be a total of 45lbs. Is save almost 17lbs in each rear setup and probably around 14lbs (staggered setup) each front setup. A total unsprung weight savings of over 60lbs! This equates to approx .3 sec off the 1/4 just like that. Plus since we're talking unsprung weight your steering and breaking will be greatly enhanced! I was really thinking about doing this for a while but just decided to throw more power at her. Lolol
Just examples of how little things can make a big difference. Swap out the hood and or trunk to CF, relocate battery to trunk, get a lightweight driveshaft and drive axles (both also unsprung items). You get the idea. But it does cost money though...unfortunately.
