kabooski

What MPH are some of you getting in third gear

Today I did a little test
Punched it from a second gear roll
@35 MPH

and I hit 112MPH at 7200+RPM in 3RD Gear
and most likely could of revved upto 9K If I wanted
maybe got even more MPH

I'll find out this wendsday
when I take my car to the track for the 1st time
after the MicroTech install and new Upgrades

Evil Aviator

Gearing-based formulas (do not take into account other factors like horsepower required, drag, wind, road grade, tire traction, speed governors, etc.):

Speed in mph = (Rear tire circumference in inches * engine rpm) / (Transmisison gear ratio * Differential ratio * 1056)

If you don't want to bother jacking up your car and measuring your tire, this formula will be fairly close, although manufacturing tolerances vary in the tire industry:

Circumference in inches = pi * (Wheel diameter + (2 * (Aspect ratio * Tread width in millimeters / 254)))

For example, given a 205/60 R15:
Wheel diameter = 15 in
Aspect ratio = 60
Tread width = 205 mm

Calculated circumference = 77.55 in

kabooski

hmm

well I have 255/50/16's in the back
front are factory stock spec's
4.10 rear
stock 87 TII tranny

The real test should come this coming wendsday- If I can maintain 110+ MPH down the 1/4 which should put me in the 12's no?

RylAssassin

Arent there other factors that have somthing to do with getting to 110+mph down a 1/4 mile strip??

Chimeron

I've never topped out 3rd, but in stock GXL I had the computer cut me off at about 72 in 2nd. Pretty damn swift for a 2nd gear.

Scott 89t2

since your tires are bigger then stock your speedo isn't right anyways. and you'll be able to go faster in 3rd then stock cars at the same rpm. and you'll be going faster then your speedo says.

Rxmfn7

iTrader: (4)

Im pretty sure in my N/A at 7000rpm in 3rd, Im at about ~95MPH. Thats just off the top of my head, Ill try it out tomorrow and get back with a more accurate reading. This is with stock wheel/tire size.

Evil Aviator

Only the drive wheels matter for the purposes of the gear-based calculations. 255/50/16 would calculate out to about 81.8 inches circumference. The stock TII transmission has a 1.391 3rd gear ratio. Therefore, your speed at 7,200 rpm in 3rd gear would calculate out to 98 mph, and 9,000 rpm in 3rd gear would calculate out to 122 mph.

Oops, I forgot a decimal. Here is the correct formula:

Circumference in inches = pi * (Wheel diameter + (2 * (Aspect ratio * Tread width in millimeters / 25.4)))

Also, for those who don't know the deal with aspect ratios, they are a decimal (like percentages). For example, you would enter 0.60 into the equation for an aspect ratio of 60.

Sorry for the confusion.

Yes, but you can estimate the times and speeds using basic formulas. There are many online calculators on the internet. Here are some of them.
http://www.geocities.com/MotorCity/4601/hpcalc.html
http://robrobinette.com/et.htm

$150FC

why is this a poll? it's a mathematical equation :/

Evil Aviator

It's a poll to see who has an accurate speedometer, and/or to see what kind of gear ratios and tire sizes people are running.

Evil Aviator

Double Post

xfeastonarsex

iTrader: (5)

My escort can hit 43mph in 1st before rev limiter, and in 2nd 74mph.

Rxmfn7

iTrader: (4)

What the hell kind of escort do you have? I drive a '95 LX daily, and in 1st at redline Im doing about 30.....2nd cant be much more than 50..

Anyways, Im about to go do a little "test run" in my FC and see how fast I am going at 7000RPM in 3rd, and maybe 4th

1987RX7guy

iTrader: (3)

I get around 90-95 in third with stock sized 15's I think its 205's on vert wheels. I usually don't use third like that but I know since I redline once a day heading home.

Rxmfn7

iTrader: (4)

OK, just got back from a little test run. I hit about 95MPH at 7k in 3rd. This is with 205/60r15 (stock size) Im at about 115 at 5k in 4th....but I ran out of "safe" road to try any faster.

kabooski

Well wouldn't you know it looks like it may rain tommarow
So there maybe no track day

Which Sucks!
I'm dying to try out my car at the track

kabooski

Hey Thats Pretty good! 3RD Gear pull for a N/A


Note:
can a MOD alter the Poll for me
I should of made the last option 101-120

plz change it if you can
Thanks

Rxmfn7

iTrader: (4)

Damn.... that means I did all those 110+ MPH runs for you for nothing..

NA_VersionFC3S

just did it today, got to 91mph at 7000 rpm in 3rd

tim

DoingAnything

in my s5 i hit 102mph in 3rd at 8k going uphill . i'll actually check today on my way home if there is no traffic, and let you all know... Something in my head is telling me i hit 112mph before in 3rd... we shall see. this is on the stock 15's and tyre size.

SureShot

Cruising in 5th at 55 -- drop directly to 3rd: & go..
3MB Video
The Speedometer shows 110.
Actual speed (Via GPS) = 101.

Hmm - 17 seconds to get to 100 - The dark side beckons..

kabooski

Ok here it is, I finnaly made it to the track yay! no rain

Best time was a 12.60@111.87(bit of slippage in clutch in 2ND and 3RD)
pulled all the way thru 3RD gear at 8K+

Never hit 4RTH

Check the MicroTech section for a full Timeslip

kitchen

That's nuts. Nice run.

amused

thats on a different turbo then stock, right?

i was under the impression that the t-18 chokes, so in the 1/4 you wanna drop to 4th at some point because at 7k its not doing anything for you anyway

opinions? i'm curious as to what i should be shifting at during my 1/4

kabooski

Yea I have a Big T4 turbo running 14PSI
which could be a reason for the 3RD gear pulls
or maybe the weak clutch?

Well see this weekend I'm getting a ACT clutch installled
have right now a Stock Pressure plate with a Kevlar Disk