STi

[ls1fun99]

MAnn let me tell yall something those WRX sti's are fast. i was driving around mopac in austin with two of my friends.(300 pounds ext.) when i see this STi i heard him before i saw him anyway i get next to him trying to get him to slow down to like 55 but he wasnt having it so i come up to him agian in 4th at about 4 grand haha i hear his turbo spool and we take off we were dead even to about 115 then i pull a bit(1/4 car) then i think that we got hit by radar full on cuz he slamed on the brakes. it was fun for the 20 secs it lasted. just wanted to share.


STi

[stereomandan]

Wow, pretty impressive, considering you had two guys in your car with you.

Good thing you raced him from a roll. May have been pretty tough from a dig.

Dan

[robvas]

He probably had mods. An STi won't trap anywhere near 108 stock.

[SergioEK9B18C5turbo]

Originally posted by robvas
He probably had mods. An STi won't trap anywhere near 108 stock.

Very true and the stock BOV isnt that loud

[tweetybirdy]

even the WRX is a quick little car, my good friend has one and being an ex-dsm'er i played around under his hood a little and by throwing on a PVC intake with a extra K&N i had, a $30 home depot boost controller and a removed muffler he went 13.8 @ 96, but from a roll, once he gets spool he, i am not pullin on him that hard, i would say that if he wasn't to pull an AWD launch out of the hole he would trap somewhere around 98-99 mph. For $30 i would say that is a quick car....

[stereomandan]

Originally posted by tweetybirdy
even the WRX is a quick little car, my good friend has one and being an ex-dsm'er i played around under his hood a little and by throwing on a PVC intake with a extra K&N i had, a $30 home depot boost controller and a removed muffler he went 13.8 @ 96, but from a roll, once he gets spool he, i am not pullin on him that hard, i would say that if he wasn't to pull an AWD launch out of the hole he would trap somewhere around 98-99 mph. For $30 i would say that is a quick car....

What do you mean by not pulling a AWD launch. The AWD launch is their only advantage. How would they trap higher any other way?

Dan

[stereomandan]

Originally posted by Steve Y
Because sometimes with superior traction, you lose trap speed. It is a very wierd phenomenon that I have no explaination for.

People have said this before, and others have said

I have never seen nor heard proof of this happening.

Dan

[stereomandan]

Originally posted by Steve Y
Take a car like mine or a Camaro that is trapping 101 with street tires. Put slicks on it and it will likely run mid 13s at 99 or so. Anybody else see this happen on their cars?

Just look at how much more rotating mass you have with slicks. That will slow any car down.

Cut a 1.8 vs a 2.2 sec 60' time on the same tire, and the 1.8 sec 60 run will have a faster trap. At least that's my experiance from all the runs I've done, or seen.

Dan

[Antz97ZNJ]

majority of those sti's run real real low in the 13's if not crack 12's stock

[John M]

The traction vs. trap speed happens because racing involves 3 aspects: time, distance, and speed.

Say you have two identical cars and one has slicks. One may turn 14.0 @ 100 and the one with traction may turn 13.6 @ 98. Why? The second one had .4 seconds less time to accelerate, but covered the distance quicker. The other car took longer to do it but had .4 seconds more time to accelerate, giving it 2 more mph.

That's over simplified but it works.

[SergioEK9B18C5turbo]

Originally posted by John M
The traction vs. trap speed happens because racing involves 3 aspects: time, distance, and speed.

Say you have two identical cars and one has slicks. One may turn 14.0 @ 100 and the one with traction may turn 13.6 @ 98. Why? The second one had .4 seconds less time to accelerate, but covered the distance quicker. The other car took longer to do it but had .4 seconds more time to accelerate, giving it 2 more mph.

That's over simplified but it works.

I call it the sling shot.....when your spinning and finally catch momentum the ET is slower but the trap is amazing...*cough* 120mph 13sec supra *cough*

But it can also work where by increasing traction you can launch harder and actually gain a mph or two because you leave the line harder....I know with my car on slicks the trap may come down a bit but not by much and the quicker 60 is seen on the ET...in the car I can feel it launch much harder and is able to accelerate where it would normally spin....

[stereomandan]

To be honest, what you are both saying does not make sense. There is no "slingshot effect" and there is no "time to accelerate" I'll explain:

Let’s exaggerate it even further. Let’s have one run be a 4 second 60’ time and the other a 1.5 sec 60’ time. Which car is going faster at the 60’ mark? Obviously the one that got there in 1.5 seconds. Knowing that, there is still another 1260 ft to go before the ¼ mile is over. So on the 1.5 second 60’ run, the car is already at a much higher speed at the 60’ mark, which results in a much faster trap speed at the end of the ¼ mile. It works no other way, assuming nothing changed on the car.

Looking at this from a time perspective does not work. The time is the effect, not the cause. You get a quicker time because you cover the distance faster, at a higher speed. You can’t say something like “you only had 13.6 seconds to accelerate” You got the 13.6 sec run because you made it down the track faster.

A faster 60’ time will result in a faster trap speed, all other things being equal. I think people run into problems and start to think otherwise when they change stuff on their car to get a better 60’ time, but don’t realize that it hurts your acceleration. (like heavy slicks, less efficient larger rear ends…). This changes the way the vehicle performs. It helps the 60’ time, but can easily suck up horsepower, or add resistance to acceleration.

Dan

[96ZRDR]

Time is the Effect, but there are too many variables that result in higher traps.

Our car in question: Full Bolt-On, Hotcammed 6-Speed Camaro.

On regular radials: 2.4-2.5 60ft, 1/8 trap 82-83, 1/4 trap = 107-108.

On wider Drag Radials: 2.0-2.1 60ft 1/8 trap 84-85, 1/4 trap = best of 110.8X.

Our experience is that with traction, we get higher trap speeds and not the other way around.

Too many variables, and we blame it on engine bog because of no traction.

I'll explain,
CAR A - regular tires

What happended? Car A takes off and spins hard. (car hardly moves forward, but climbs its power band) 1st gear at 6,200 rpm - SHIFT. Speed at the time 25 mph (not actual just hypothetically speaking).

2nd Gear - Spins more, take it to 6200rpm - shift. Speed at the time of shift 40.

3rd Gear - 3rd gear goes in and results in BOG, because engine is dropped out of its power band, which results in dramatic slowdown of acceleration, which in the end results in lower traps and more time.

CAR B - Drag Radials

What happended? Car B takes off and little to no spin. 1st gear at 6200 rpm - shift. Speed at the time 30 mph. (not actual just hypothetically speaking). Car is able to maximize its power band through 1st gear because of no spin. Results lower 60ft, higher speeds.

2nd gear - Little to no spin. Able to maxime powerband in 2nd. Shift. Speed at time of **** - 48. Accleration rate remains stable.

3rd gear - Engine remains on its healthy part of its powerband and roars to the finish line. Results, maximizes its powerband in all gears = higher traps, less time.

There are many variables - such as time to shift etc.......

But there are many variables and not as simplistic as people think. But it is common sense.

But typically our experince says that lower traps equals better times and higher traps.

[stereomandan]

Originally posted by 96ZRDR
Time is the Effect, but there are too many variables that result in higher traps.

Our car in question: Full Bolt-On, Hotcammed 6-Speed Camaro.

On regular radials: 2.4-2.5 60ft, 1/8 trap 82-83, 1/4 trap = 107-108.

On wider Drag Radials: 2.0-2.1 60ft 1/8 trap 84-85, 1/4 trap = best of 110.8X.

Our experience is that with traction, we get higher trap speeds and not the other way around.

Too many variables, and we blame it on engine bog because of no traction.

I'll explain,
CAR A - regular tires

What happended? Car A takes off and spins hard. (car hardly moves forward, but climbs its power band) 1st gear at 6,200 rpm - SHIFT. Speed at the time 25 mph (not actual just hypothetically speaking).

2nd Gear - Spins more, take it to 6200rpm - shift. Speed at the time of shift 40.

3rd Gear - 3rd gear goes in and results in BOG, because engine is dropped out of its power band, which results in dramatic slowdown of acceleration, which in the end results in lower traps and more time.

CAR B - Drag Radials

What happended? Car B takes off and little to no spin. 1st gear at 6200 rpm - shift. Speed at the time 30 mph. (not actual just hypothetically speaking). Car is able to maximize its power band through 1st gear because of no spin. Results lower 60ft, higher speeds.

2nd gear - Little to no spin. Able to maxime powerband in 2nd. Shift. Speed at time of **** - 48. Accleration rate remains stable.

3rd gear - Engine remains on its healthy part of its powerband and roars to the finish line. Results, maximizes its powerband in all gears = higher traps, less time.

There are many variables - such as time to shift etc.......

But there are many variables and not as simplistic as people think. But it is common sense.

But typically our experince says that lower traps equals better times and higher traps.

I agree that better 60' get's higher traps.

O.k. first, drag radials will hurt acceleration if they are heavier than your street tires, but it may or may not be a whole lot. There would have to be a pretty large difference in tire/rim weight to make a big difference, but they will put more resistance on getting moving because of the added rotational mass. The good traction normally overcomes this drawback, so you don't see the potentian loss of speed. So I mostly agree with you here.

First question. If, in both situations, you are shifting out of second at 6200 rpm, why do you bog in the first instance and not in the second instance. 6200 rpm in both cases is at the same speed(unless you are saying that your drag radials have a much larger tire diameter, or you spun ALL THE WAY through 2nd in the first instance) In that case I see what you are saying, although this is highly unusual, because it takes a fairly lousy driver to make this happen, or mucho power.

Also, you are comparing a car with 2 different tires, so not everything is equal, but all in all, I agree with you. It's just another example of how a better 60' = higher trap speed.

Dan

[96ZRDR]

Well lets just say that cant go Full WOT on a 6-Speed Full Bolt-On Hot Cammed, 3.73 rear-ended car, on stock 245/16 radials.

AT WOT this car wont catch grip until midway through 3rd. So basically if you cant go WOT from the start at a dragstrip you are not maximizing your cars potential. Sure we can go mid throttle trough first, second, until we can get 100% throttle but by then who cares.

It is much easier on our Auto 93 T/A