6500rpm in second..what speed au wagon?

[Stav]

Guys..what do you think.If I hold second gear to 6500 rpm in second gear,then what speed will achieve? I have 4:11 diff ratio.

[JC]

137km/h

[Stav]

Originally Posted by JC

137km/h

Thanks mate. it is a bit of a bugger though ..I was hoping to get more kmph and possibly do the 1/4 mile in 2 gears.

Is it hard to calculate?

[Mr Hardware]

137kmh in second with a 4:11!
you reckon?

[Stav]

I am hoping to see 80 odd kmph in first and 160 in second.

[Stav]

Originally Posted by Mr Hardware

137kmh in second with a 4:11!
you reckon?

with a 6500 rpm limit?If you know better then please explain..

[Clarke AV]

I
I Hope this is some help

[Road Games]

Originally Posted by Stav

with a 6500 rpm limit?If you know better then please explain..

Ummm Stav sorry to jump in but second gear in my car is approx 150- with 3.45 at 6500rpm, hence i drop my revs back to 6200 and change into third and ran my fastest numbers ???
Baxter has 3.23 and i reckon with his limit being around 6700 or so he will hit 100mph in 2nd easily , pity he doesnt have the power though YET !!

Your 4.11s wont have a hope sorry ...... :

[Stav]

Is that an online calc? Link if you can?

[Clarke AV]

http://www.eecanalyzer.net/shop/

It is good for data log's for TwEECer RT Users

[Stav]

The calc is a bit off. I have done 3rd gear at 97mph crossing the line.i estimate rpm at 5200 in third.

Dazzler.No worries mate.I need a limiter of 7700 rpm to achieve the same.

[Stav]

Originally Posted by DAZZLER351

Ummm Stav sorry to jump in but second gear in my car is approx 150- with 3.45 at 6500rpm, hence i drop my revs back to 6200 and change into third and ran my fastest numbers ???
Baxter has 3.23 and i reckon with his limit being around 6700 or so he will hit 100mph in 2nd easily , pity he doesnt have the power though YET !!

Your 4.11s wont have a hope sorry ...... :

3rd gear is where the converter is fullly locked and torque mutilpication dies.The usage of first and second should nett me a better time ..I hope..hehe

I wonder what the wagon would run if I took it to 6500 like yourself ?

[ratter]

depends on tyre height,not just printed measurements, but wear also, if auto you will also have to factor some slippage front the convertor

[Stav]

Originally Posted by ratter

depends on tyre height,not just printed measurements, but wear also, if auto you will also have to factor some slippage front the convertor

I dynoed my car at the time of the converter swap. 133 rwkws pre and 131 rwkws after.I dont think there would be much slippage over standard.Ratter ..mate I think I am going to head down to wsid drags next week to answer this question for myself. Hopefully my edt thingy will be ready.

[Road Games]

Originally Posted by Stav

3rd gear is where the converter is fullly locked and torque mutilpication dies.The usage of first and second should nett me a better time ..I hope..hehe

I wonder what the wagon would run if I took it to 6500 like yourself ?

Not familiar with your engine mate , only my own and that is where my knoweledge lies, the faster i rev it the quicker it goes, and now with a genuine 250 + rwhp i would love to upgrade to a typhoon fuel pump and regulator ....
For safety sake

[ratter]

just a note. All convertors have a percentage of slippage, which is why late model convertors have lock up clutches, but these clutches are normally only applied at light throttle.

[Stav]

Originally Posted by DAZZLER351

Not familiar with your engine mate , only my own and that is where my knoweledge lies, the faster i rev it the quicker it goes, and now with a genuine 250 + rwhp i would love to upgrade to a typhoon fuel pump and regulator ....
For safety sake

Man..my wagon dissapoints me when I floor it in 1st and it climbs so fast /smooth it starts pulling even harder the rev limiter stops the fun. I wish it would spin to 7000 rpm because I reckon it would go there without hestation. The car wants to go and the limiter kills the the show!! Still I have fun with but I want to set the wagon free...its like a wild horse that wants to do the bolt but is still tied to the fence!!
I am already running turbo injectors and a 700hp fuel pump.
it was a thought to go down the 1/4 mile with 2 gears but thats life..

[Stav]

Can we change 3rd gear in the auto gearbox for a more aggresive response?

I think 3rd gear ratio in the box is not that toey.

[T3man]

Originally Posted by Stav

Guys..what do you think.If I hold second gear to 6500 rpm in second gear,then what speed will achieve? I have 4:11 diff ratio.

You can do the calcs for yourself pretty easily. You need to know your gear ratio, diff ratio and tyre revolutions/km.

The ratios are easy - straight from the book. Accurate tyre revolutions is tricky.

The way I do it for greatest accuracy is to place the car on a level concrete drive and mark the bottom of one tyre with chalk and also the concrete at this point. Then drive forward exactly one wheel revolution and make another mark on the concrete - note the distance between the two marks eg 1850mm which is 1.85m. Divide 1000 by 1.85 and the answer is how many revs your wheels do per km.

Then you can use this formula to calculate ...

km/h per 1000 rpm = 60,000/wheel revs per km/diff ratio/gear ratio

An example ...

Given a diff of 4.1:1 (your diff); gear ratio of 1.45:1 (2rd gear auto but not necessarily yours); 510 wheel revs per km. In the formula you have ...

km/h per 1000 rpm = 60,000/510/4.1/1.45 which becomes

117.65/4.1/1.45 which becomes

28.69/1.45 which finally equates to

19.79. So at 6500 rpm the car will be doing 19.79x6.5 which is 128.63km/h

Hope this helps.

[Road Games]

Originally Posted by Stav

Can we change 3rd gear in the auto gearbox for a more aggresive response?

I think 3rd gear ratio in the box is not that toey.

Exactly why i want a BF with 6 spd , my dads car feels responsive but not like my mate swannies car ......
I hate the way it dies about 50m from the finish line but what do ya do ......

[Stav]

Originally Posted by DAZZLER351

Exactly why i want a BF with 6 spd , my dads car feels responsive but not like my mate swannies car ......
I hate the way it dies about 50m from the finish line but what do ya do ......

2 Speed gearbox..heheWhat gear did swany hit the line with?
T3 man...good stuff ..128 kmph isnt too bad for the revs.I may be able to use this info to my advantage..Thanks

[protd]

you want 2 gears fit a glide..

[Stav]

Heheh its tempting but the wagon still has street duties everyday..maybe when it becomes a full drag car.

[big_waity]

A mate of mine had 4.11s in his AU and the speed limiter kicked in at about 129!
If you want fast 1/4 mile times with 4.11s use all gears!

[T3man]

Originally Posted by Stav

2 Speed gearbox..heheWhat gear did swany hit the line with?
T3 man...good stuff ..128 kmph isnt too bad for the revs.I may be able to use this info to my advantage..Thanks

Well just remember I plucked some figures out just to show you how the formula works - the figures may not be the same for your car mate. For example your second gear ratio may be 1.39 ??? And 510 wheel revolutions may be a bit off compared to your car as well. But the formula is there for you and you can experiment with it putting in different size tyres and gear ratios etc to achieve an end result. If for example you do the calcs for your car and find that you are just falling short of your desired terminal speed in second gear with the tyres you have then a step up to the next size tyre may just get you the result you want. remember taller tyres equal taller gearing ie. higher road speed for any given RPM.

[Stav]

first is 2.39:1
2nd is 1.45:1
3rd is 1.00:1

I will work it out.

[Stav]

That dam 3rd gear is too lazy!! these cars would be heaps faster down the 1/4 with a different ratio 3rd gear. 1:1 is just wrong for the job. No wonder the six speed auto boxes are thrashing us. Having a more aggressive ratio there is flogging us!! We need to be able to use the first 2 gears instead.

[T3man]

Hey Stav I see you want to achieve 160km/h in second ...

To do that you can work back through the formula to find what diff ratio you need.

Say your car's wheels do actually turn 510 times per km ... then here's how your formula works for you:-

Given you want to do 160km/h at 6500 rpm. The 160/6.5 = 24.62. This is how many km/h per 1000 rpm that you have to achieve with your gearing.

So in the formula:-

24.62 = 60,000/510/1.45/diff ratio

24.62 = 117.65/1.45/diff ratio

24.62 = 81.14/diff ratio OR

diff ratio = 81.14/24.62

diff ratio = 3.29

[T3man]

On the other hand if you want to turn the car into a drag only monstor then you will want to go for 160km/h in third gear ... LOL

24.62 = 60,000/510/1.00/diff ratio ...

calculates out to a required diff ratio of 4.78.

[Road Games]

Originally Posted by T3man

On the other hand if you want to turn the car into a drag only monstor then you will want to go for 160km/h in third gear ... LOL

24.62 = 60,000/510/1.00/diff ratio ...

calculates out to a required diff ratio of 4.78.

Thank you very much for that info :
Now i know my friend with the 3.23s will not be shifting into 3rd any more !!!! :evil3: :evil3: :evil3:
And coincidently that is the approx ratio needed of ours to beat a 6 spd !!