98sscamaro

iTrader: (1)

Hey
I was curious about the different quartemile times people ran in GS400's with mods and stock. Could people please list the info about the quartermile and then what they have done to the cars.
Thanks


What kind of improvement has been seen by replacing the TQ with a dragon?

What kind of improvement has been seen with an SRT intake?

I have a 98 SS camaro and i got it to run a 13.52 and i am going to sell it and buy a GS400 and wanted to know what i have to do to get the GS to run close to that or at least beat my friends mustang he ran a 13.94.

Thanks alot for the info

redgs4

13.9's are about the best you will see without a SC or Turbo. At what track were you getting those times? A bunch of the Norcal locals hit the Sacramento raceway at least once a season if you are interested.

98sscamaro

iTrader: (1)

We went out to sears point and ran those times. I would be very interseted in going out to the track with you guys I also have a 69 pontiac lemans with a chevy 454 that has 488 hp and 573 foot pounds of torque that i want to race this summer. I am going to try and go to the dyno day that you guys are having.

SeattleGS400

iTrader: (1)

Motor Trend. Feb 1998

Performance (stock)

- 0-60 mph acceleration 5.7 seconds
- 1/4-mile acceleration 14.3 seconds
- Top track speed 149 mph (electronically limited)
- Fuel consumption 17/24 mpg city/highway
- Aerodynamic drag coefficient 0.29

Typically, it seems most members run in the mid-14's stock (not bad for an automatic). If you added a TC and an intake, it might break into the high 13's, assuming you don't go with 18" rims or larger.

gserep1

Hello,
I recently got a chance to see my GS4 hit the electronic limiter at 149 mph. It actually gets up there, (and qute easily I might add.) I was pleasantly suprised. Plenty fast enough for me for now, but with a turbo or supercharger, who knows. I wonder how this extra speed might affect the transmission and differential? I wonder about the potential for damage to a stock driveline, and at what speed. It is SMOOTH all the way up to the rev limiter, though.

Just my $.02

98sscamaro

iTrader: (1)

If i put a TQ, SRT intake, HKS hyper exhaust, and a 3.76 LSD What do you think i would run in the quarter??

floyd

How bad do 18's (wheels) slow the car down??????????????


Floyd

redgs4

How bad do 18's (wheels) slow the car down??????????????

How much depends on how heavy... Pick the right 18" rims/tires to minimize the impact. Heavy wheels will affect your braking, too. Weight becomes easier to manage than adding horsepower at some point, so you need to be careful with all your mods [from wheels to stereo equipment]. You don't have to count the grams but just be smart about what you add.

If i put a TQ, SRT intake, HKS hyper exhaust, and a 3.76 LSD What do you think i would run in the quarter??

13.9 to 14.3, depending on conditions. There have been a few CL member that have run strong with minimal mods, but I have not seen it under "norcal" conditions. I'll freely admit that we are probably lacking in technique and tuning which costs us a few 10ths. I'd like to try sears point -- I hear the track is in much better condition than Sacramento. Hope to see you at Dyno Day!

I also have a 69 pontiac lemans with a chevy 454 that has 488 hp and 573 foot pounds of torque

But can it corner?

SeattleGS400

iTrader: (1)

I ran into some info at LexExtreme.com a while back on this, and here's my summary:

SYNOPSIS

Lexus LS400 (1st gen) owners debate the merits of switching from factory 16" wheel (225/60R16) to a lighter aftermarket wheel (245/45R18)--they seem to be mechanical engineers or at least have some sort of physics background in it (of course, a couple in the post obviously don't). The debate: Are aftermarket 18" wheels (lighter than stock) better than 16" stock wheels?

The stock 16" wheels (24 pounds) plus tires (24.4 pounds) weigh a total of 48.4 pounds. The aftermarket lightweight 18" wheels (19 pounds, shaving 5.4 pounds over stock) plus tires (28.5 pounds) weigh a total of 47.5 pounds (total of 0.9 pound savings over stock setup). From the outset, it seems as if the lighter wheels (and overall ligher setup) would allow for better acceleration. However, as the main mass of the 18" wheels and tires are further away from the rotational axis of the wheel, through mathematical computations, they come up that using lighter 18" rims (although wider in width for better cornering) is like adding 146 pounds of dead weight to the car--hence slowing down the acceleration.

Conclusion: Using larger wheels on a car, if not significantly lighter than stock, will slow down acceleration of your car. Those running 20's on their vehicle know this. However, if you are going up in wheel size, judicial selection of lighter-than-stock wheels must be exercised to minimize the accleration drawback. On a simlar note, the tire weight will also have a role on this effect on this as well.

HERE'S THE ORIGINAL QUOTE AND THREAD LINK

http://www.lextreme.com/forum/viewto...r=asc&start=30

My example compared the factory 16 x 7", 24 pound wheel (so I am told, have yet to weigh it myself) to the 18 x 8", SSR GT1 19 pound wheel. The factory tire is a 225/60-16 weighing aprox 24.4 pounds and having a diameter of 26.6". A comprable diameter tire, 245/45-18 weighs around 28.5 pounds. So the OEM assembly weighs 48.4 pounds and the 18" assembly weighs 47.5 pounds. Interestingly enough, even though the 18" assembly is lighter... its net ME would be probably be a negative as it would would have more weight biased to the outside.

Let me run the program to see...

WOW... I just ran the above and my suspicions were correct... this assembly, even though 1 pound lighter, has a much worse ME and in fact had a net effect of adding 146 pounds to the chassis !!!

Dennis-C

SeattleGS400,

Good info, the majority of the weight is the outside rim/ lip area.

You also have to pay attention to the rotational weight. If all 4 rims and tires are lighter by 20 lbs, not only does it make your car lighter, it takes less energy to rotate those rims/ tires. Those 20 lbs turn into +/- 80lbs.

FutureGS400

Great stuff on wheel/tire weight! While I agree with the information, I was surprised to learn that the stock 16" wheel with the 225/60 16 tire weighs 48 lbs! My GS 17" 5 spoke stock wheels and tires (RE030) weighed 43 lbs!. And considering that is a larger wheel and tire, those are some heavy 16" wheels!
People sometimes forget that lightweigt wheels are only part of the picture; as this post shows that the 18, 19 and 20 tires can weigh quite a bit more. Obviously that will vary somewhat due to size (width) and different brands etc.
If you wanted the best times for your GS in the 1/4, you would want some really light (12-15 lbs.) 16" forged wheels in a wide enough size to still have the rubber on the ground for traction, but handling and appearance condsiderations have to be considered too of course.
My 18s are no featherweights, but I think are a good balance of strength, reasonable weight (about 27 lbs.) and appearance. I'm sure most, if not all, people on 20s are aware of the performance issues and have made a personal choice that the look is more important than performance. It's all about trade-offs and knowing what they are and accepting them.
The other thing about 20s though is in addition to the added weight (and the location of the weight farther from the center axis) is they will be taller (larger diameter) than stock by around 1" or so and will have the effect of raising the gear ratio (lower numerically) which will also hurt acceleration a bit. But if you like the look, who cares?

roenick7

I ran 13.2 -13.3 all day with 7.5 lbs boos S/C OR a 150 shot of NOS. LSD T/C; 19" rims; Exhaust; PLugs....

You can get 12.7 with 17"s and cheater slicks

omegagavin

B]If i put a TQ, SRT intake, HKS hyper exhaust, and a 3.76 LSD What do you think i would run in the quarter??[/B]

13.9 to 14.3, depending on conditions. There have been a few CL member that have run strong with minimal mods, but I have not seen it under "norcal" conditions. I'll freely admit that we are probably lacking in technique and tuning which costs us a few 10ths.



So you're saying that after several thousand in mods you get basically no improvement on 1/4 mile times over motor trends results?

RMMGS4

iTrader: (5)

No, no one said that the mods offer no improvement. You're comparing data taken from two different sources, which is not a fair comparison.

Magazine test results are not real world for most of us. Those tests are done with experienced drivers under usually very ideal conditions. There IS an improvement doing these mods over a stock GS, but we need to use a different baseline time; one that reflects the track conditions we were working under.

At NorCal the SAC track has been known to be slow. This is due to many factors, the main one being the ambient temperature at the track can usually be between high 80s to low 100s. That's just the typical wheather in SAC during the summer.

We ran a stock GS on the track and the best of several runs just barely broke 14.9. The same car modded with an LSD, TC, Intake and exhaust ran a 14.2.. Again, we feel there is more room for improvement through technique, since all of us who ran our cars have at most, 5 minutes of total track time at the drag strip.

We also had the priviledge of seeing an almost new C5 Corvette do several runs when we were there. All of the runs were about 0.5 sec slower than what the magazines say the car does.

So if we compare the C5 data, relative to the magazine reports, we can extrapolate a 13.7 sec quarter mile for our LSD/ TC/ Intake/exaust modded GS. Add an experienced driver and ideal conditions to the formula and we get a magazine equivalent time of 13.6 sec.


The bottom line is that the improvement gained by those mods was about 7 tenths of a second. What you get in actual 1/4 mile times, compared to what the magazines report, may vary.

omegagavin

You're right, of course. Good information. I am curious as to what exactly an experienced driver can do to improve times with an auto tranny car. It seems as if there is a limit to what one can do with AT.