wrx cobb stage 2 vs. evo

[13secwrx]

I wonder if my car is a bit of a freak....I often pull stage 4 wrx's as Ive raced 2 of them and they all had bigger intercoolers....I also remember beating alot of cars when I was stage 2...I mean you talk of 2-3 ft on an evo and I put cars on them....I really think my engine is a bit of a freak......I also will say that I have not run into any modded evo's but I am a bit worried about them.....I only want my stroked engine and gearbox to match well w/the even bigger turbo so that I hope to not worry about much at all....Turbo xs w/that set up laid down 455whp.....OMG...What that would be like.....

[04EJ25]

How well can your dad drive?

My suggestions:

1. From standing still- launch at about 4500-5000 RPM's with a quick but smooth clutch "drop"

2. Shift at about 6300 to 6500RPM's; NOT redline!

3. I don't know how the EVO is geared, but try to race him in the 1/8mi, NOT a 1/4...

You should do well. If you can race a hell of alot better than your dad then try to take him in the 1/4.

I just got my Stage 2 today with a Perrin uppipe, and Perrin DP (not a full turbo-back). In the rain w/ my G-Tech I ran a 13.7@101MPH. That was in the rain! I've been messing with the G-Tech maps I've stored to find where peak HP is. It looks like my Rex is at 220HP between 5800 to 6500RPM's depending on the run. After that, HP drops off. My fastest 1/8mi run was 8.91@81.9MPH. That was in the rain today too. I hope that helps! Good luck!

[verc]

Why not shift at redline?


...this is a very common driving misconception among drag racing enthusiasts.

If you do the numerical calculations for torque multiplication, you will find that at redline in gear X you will be putting out much more power than even PEAK power in gear X+1.

[04wrx4keeps]

I dont know if it might have been because it was raining and he spun a little bit (hes not the greatest driver, but hes launched awd's quite a bit before), but i raced a friend of mine from a stoplight in his new evo, and with him and 2 people in the car i actually pulled on him in 1st and 2nd till we stopped about 60. I only have a catback and panel filter, so i expected him to stomp me, even with the extra weight. From riding with him though it seems like his gears are set up better for 3rd+ than for 1st and 2nd.

But im also wondering as my perrin downpipe should be here soon, if getting the cobb chip will give me enough to at least shut him up a little bit, hes kinda cocky about his car beating mine.

[04EJ25]

Originally posted by 04wrx4keeps
I dont know if it might have been because it was raining and he spun a little bit (hes not the greatest driver, but hes launched awd's quite a bit before), but i raced a friend of mine from a stoplight in his new evo, and with him and 2 people in the car i actually pulled on him in 1st and 2nd till we stopped about 60. I only have a catback and panel filter, so i expected him to stomp me, even with the extra weight. From riding with him though it seems like his gears are set up better for 3rd+ than for 1st and 2nd.

But im also wondering as my perrin downpipe should be here soon, if getting the cobb chip will give me enough to at least shut him up a little bit, hes kinda cocky about his car beating mine.

I've got COBB's Stage 2 w/ Perrin's Uppipe and DP. Look at my post above. I've listed some #'s...

[04EJ25]

Originally posted by verc
Why not shift at redline?


...this is a very common driving misconception among drag racing enthusiasts.

If you do the numerical calculations for torque multiplication, you will find that at redline in gear X you will be putting out much more power than even PEAK power in gear X+1.

I was never good at math, but I do know that torque is power down low, with HP being power at higher RPM's. So how does this X/X+1 go again?

[emosubaru]

Originally posted by 04EJ20
I was never good at math, but I do know that torque is power down low, with HP being power at higher RPM's. So how does this X/X+1 go again?

rrrrg! not true at all!

torque and HP are just two different ways of measuring the same thing!

while drag racing you want to be putting the most power to the wheels for the longest amount of time.

when you're switching gears, you're effectively coasting, so as long as the finish line goes by by the time you're out of gears, it's preferable to have somewhat taller gears.

what this guy is saying though is that you should shift at redline because you're in a lower gear, which will put more power to the ground...

if you're having trouble thinking this through, just remember how they tell you to start in second when you're driving in snow. the wheels move faster with the same amount of power, but there's less power going to them per rotation...

what this redline guy is not taking into account is that gears and their relationship to your engine are extremely important to acceleration. now with most imports and N/A motors, you'll only be gaining HP(forget torque for now) the higher in the revs you are.

what's more important though is acceleration. in drag racing, it's not how much power is reaching the ground per rotation of the wheel, it's how fast the car is accelerating. for the most acceleration, you're going to want the most amount of power out of the engine matched to the best gearing suited for the speed you're currently traveling.

now you might be thinking okay, so mr. redline is right, you'd want to stay in the gear for as long as your engine is still climbing in revs(so your wheels will keep spinning)

but what he's not right about is that cars liket he WRX can't support the high boost that makes all the power with the stock turbo in high revs.

this is where it gets easier to look at it in terms of torque. the torque rating of a motor will acually fall in higher revs, because even though there is more horsepower in the higher revs, there is less torque being applied to the crankshaft... this will effectively give you less acceleration than when you have full boost (14psi) in the middle of the next gear.

that was probably hard to understand... but just remember that in drag racing all that matters is acceleration. torque doesn't matter, horsepower doesn't matter- unless they get you a larger rate of acceleration.

so just keep remembering- is the rate of meters per second per second higher at this RPM in this gear than it is at the matching RPM in the next? if so... keep that foot on the pedal. if not, shift up.

simple, right?

[emosubaru]

the above explination only works for the WRX(read: works for the werx) because of the torque curve.

some cars have a steadily increasing torque curve, and most likely you'd want to run those engines to redline, unless the gear was insanely tall and you'd be better off in another gear.

pretty much what matters is the last paragraph of my previous post...

so just keep remembering- is the rate of meters per second per second higher at this RPM in this gear than it is at the matching RPM in the next? if so... keep that foot on the pedal. if not, shift up.

if the torque/hp(it's all the same thing being measured, just like lenght and cm/in.) at this RPM that is being applied to the current gear makes the car accelerate at a greater rate than the matching torque/hp at the matching RPM in the next gear, it's not time to shift yet.

[04EJ25]

It all sounds good to me fellas. What sounds even better is the fact that today I walked in to Subaru, gave them the keys to my '04 WRX, and walked out with a new STi. Now were talking more horsepower!!!

[WRXin']

Originally posted by 04EJ20
It all sounds good to me fellas. What sounds even better is the fact that today I walked in to Subaru, gave them the keys to my '04 WRX, and walked out with a new STi. Now were talking more horsepower!!!

HAHAHA...dude, you must be so excited. I've seen you post something similar to this on other threads

[04EJ25]

Originally posted by WRXin'
HAHAHA...dude, you must be so excited. I've seen you post something similar to this on other threads

I'm soooo pumped dude. I got it about 5PM last night w/ 20 miles on it and it's up to 150 miles right now...

[WRXin']

Originally posted by 04EJ25
I'm soooo pumped dude. I got it about 5PM last night w/ 20 miles on it and it's up to 150 miles right now...

Holy crapola That's the joy of driving

[04EJ25]

Originally posted by WRXin'
Holy crapola That's the joy of driving

Yep, as of last drive about an hour ago I'm now at 300. I just want to break this thing in. It's 1st service is Saturday. YEE-HAW!!!

[el~sharko]

I can beat my friend's stock evo everytime from a stop or roll. From a stop were dead even till i hit 3rd and I'm gone! I have a txs stg2 with stock muffler on a wagon, so I'm just about the same weight as hime cause I weigh a good 50lbs more than him

[Dan00Hawk]

I've been under the impression that for maximum acceleration, you want to shift at whatever RPM will put you at your torque peak in the next higher gear...

So, if for example, your torque peaks at 4500 rpm, then you want to be at that exact point after you shift. If it requires you to redline to do so, then that makes the most sense. If short shifting is required, then do that.

You need to take gearing and your torque curve into consideration. I'll see if I can find the mathematical equation somewhere, and use the stock WRX's torque figures and gearing to see what comes up...