Top speed calculator?

[Kspen90]

Im looking for the formula that is used to figure top speed using the rpm, trans ratio, ring and pinion ratio, and tire size to figure theorhetical top speed. Been searchin the internet and its starting to make my head hurt and im WAY to tired to try to develop the formula myself as it would take me a long while and a notebook full of paper to do so.

 

[Chevy1925]

http://www.catherineandken.co.uk/sti/tyres.html

this one works. fifth gear is .71, what ever your gear ratio is (stock is usually 3.73 but you may have 4.10 with the stick), tire size and what ever your rev limiter is set at. you dont need to know the gear ratio of each gear in the alli for top speed

 

[Kspen90]

Thanks james, thats an extremely handy link. I was thinking of going to 3.42 gears from my 3.73 but its not worth $500 to gain 10mph on the top end.......or is it lol

 

[Kspen90]

http://www.chevymania.com/tech/trans-ratios.htm
Another handy link for everyone. If you have a stick in our truck then use the zf s6-650 ratios as per the rpo ml6 on the build sheet

 

[DAVe3283]

I use an Excel spreadsheet to do this for me. It is a work in progress, but the math for top speed is correct (assuming you have the power to pull it).

Plus, it makes a nice shiny chart!


If you notice, not only does it support 2 redlines (which are adjustable), but it shows the shift points as thicker lines so you can easily tell what gear you will be in. You just enter tire size (as either revs/mile, metric size, or diameter), and enter the 6th gear ratio if you have a 6 speed. You can also change what units are used, which is kind of neat if I do say so myself.

I'd love to hear feedback if anyone uses it. (It is a work in progress still, so be kind. :hug

 

[JoshH]

www.duramaxdiesels.com/forum/showthread.php?t=7959

 

[iPhattMatt]

So according to the first link posted, I can do 165mph in my truck and only 22mph in reverse?! HAHA!!! Too fast forward and not fast enough backwards. I set the rev limit to 3900 as a guess. what is the rev limit on the lml's? :roflmao:

 

[TeaBagger2006]

dammit Kspent fix your heap first then worry about breaking the sound barrier.

 

[jraymer]

dammit Kspent fix your heap first then worry about breaking the sound barrier.

:thumb::thumb:


ya did you ever fix that slipping clutch

 

[Kspen90]

dammit Kspent fix your heap first then worr[YOUTUBE][/YOUTUBE]y about breaking the sound barrier.

:roflmao:
Yeah yeah i know, just dont want the to do list to get to short :spit:

:thumb::thumb:


ya did you ever fix that slipping clutch

welll......about that, i ordered my dsp 5 and tuning and put a deposit on the clutch then some unforseen legal fees bit me in the ass lol so its going to be probably another month before i feel comfortable paying off the clutch

 

[whitetrash21]

appearantly my tires are too big, i cant even get a top speed number.

 

[Chevy1925]

appearantly my tires are too big, i cant even get a top speed number.

Come out here and lets do some real world testing. I know some stretches of highway outside of flagstaff that we can open her up on

 

[whitetrash21]

Come out here and lets do some real world testing. I know some stretches of highway outside of flagstaff that we can open her up on

lol... watch the egt guage and speedo race each other for the last pin

Found 135 in my lb7 once... with the ladder rack on. Sound like a pack of coyotes howling in my window at that speed.

 

[Kspen90]

lol... watch the egt guage and speedo race each other for the last pin

Found 135 in my lb7 once... with the ladder rack on. Sound like a pack of coyotes howling in my window at that speed.

I think this is an EPIC idea!!!!