SprayedLT1

iTrader: (8)

I think I broke the 3.70 gears in my Moser 9". If they're trash, I was thinking of going with a different gear ratio, and the 3.89 are tempting.

Last year I was trapping around 119/120 on 245/16 Nittos... this year I'm on 26" ET Street slicks, so I could probably get away with the 3.89 at the track without raising my trap rpm too much, if any. Thoughts?

airforcemanss

iTrader: (23)

hey, im sorry i can't help you answer your question but how can you tell where your going to be between your tire height and gear at the end of a pass?

im not where your at YET but this is info i will need.

subscribing!

SprayedLT1

iTrader: (8)

There's calculators you can use to figure out rpm at mph using rear gear ratio, trans gear, and tire height. If you have a rough idea of what your trap speed will be, you just plug that in with the other stuff and it will tell you approximate rpm. Only problem is it won't compensate for convertor slip, so it's not exact, but pretty close.

SprayedLT1

iTrader: (8)

Here's one:

http://www.csgnetwork.com/rpmcalc.html

1CAMWNDR

iTrader: (21)

3.89:1 rocks

wrd1972

iTrader: (12)

I had 3.89 Motives in my 9" last year, burned them up and went 4.11's. The 4.11's definitely felt stronger. Obviously this is the way it should be, but I do like them better.

airforcemanss

iTrader: (23)

Enter Vehicle Speed In MPH 110mph
Enter Tire Size Diameter 26.5
Enter Differential Gear Ratio :1 3.42
Enter Selected Transmission Gear Ratio :1 1
it says my rpm is 4,792

what the hell does this mean?
i still don't get it. i thought you could put say 3rd or 4th gear in and calculate your rpm by what you usually run in trap speed?

up above does not make sense to me.especially the transmission gear ratio being 1?

do you know what im saying?

Ericbigmac83

iTrader: (19)

^4th is 1:1, above means you'll run through the traps at 110mph at 4792 rpm's with 3.42 gears

airforcemanss

iTrader: (23)

i understand that part but it what be nice if you could put what gear you would be in and the rpm you would be at ya know

Ericbigmac83

iTrader: (19)

Here are the ratios for the different gears if you wanna play with them
3.36:1 2.07:1 1.35:1 1.00:1 0.80:1 0.62:1

Mikey 97Z M6

iTrader: (37)

Usually people (with manual transmissions) try to get 4th gear to top out at the finish line at their particular hp peak (in rpm). For instance, if your engine combo makes peak horsepower at 6400rpm, then you'll try to gear the car to cross the traps at that, or slightly above that rpm. Anything lower and you're giving up some potentialy quicker et's.

Unless you're trying to eliminate a shift to 4th gear, but that would give you a very low (numerically) gear and wouldn't allow you to launch very well.

Mike

airforcemanss

iTrader: (23)

so there are the 1-6 gear ratios? just double checkin? ill plug them when i get home to see what rpm they'll be at. thanks!

i understand that part. i cross at 4th too but i want to know what i would be crossing at if i throw on a taller tire and some steeper gears,etc... that's the whole point of this. thanks for an answer tho.

CUR 4 VNM

iTrader: (12)

how about 4.30's in a 9 inch and a 4000 stall? redline is 7,000 if that matters. the car is basically for the weekend and just whenever. but i basically want to keep it full weight and still feel like its on ice. although im sure it will feel like that anyways. thanks in advance

BigKap94z

iTrader: (47)

http://www.f-body.org/gears/

There is a drop down menu for your vehicle and will have a chart to show mph vs RPM. U can also do other gears at once to compare them.

OP i would go 3.89 or 4.11.

NBMZ/28

iTrader: (1)

I have a set of Moser 3.89s and absolutely love them. I'm at a good power level where I don't have to pedal 1st gear as much anymore with DRs.