I have three choices.

Here's numbers 1 and 2: http://www.teammfactory.com/gearcalculator.php?kmh=0&tirewidth=255&tireprofile=40&wheelsize=17&tirediameter1=25.03&maxrpm1=6500&finaldrive1=3.85&gearratio1=3.25&gearratio2=1.772&gearratio3=1.194&gearratio4=0.926&gearratio5=.711&gearratio6=0&trannytype=&tirewidth2=255&tireprofile2=40&wheelsize2=17&tirediameter2=25.03&maxrpm2=6500&finaldrive2=3.85&gearratioa=3.25&gearratiob=1.904&gearratioc=1.323&gearratiod=0.975&gearratioe=.711&gearratiof=0&trannytype=&tranny=Calculate+Transmission+1+%26+2

Here's number 3:
http://www.teammfactory.com/gearcalculator.php?kmh=0&tirewidth=255&tireprofile=40&wheelsize=17&tirediameter1=25.03&maxrpm1=6500&finaldrive1=3.85&gearratio1=3.25&gearratio2=1.772&gearratio3=1.323&gearratio4=0.975&gearratio5=0.711&gearratio6=0&trannytype=&tranny=Calculate+Transmission+1&tirewidth2=195&tireprofile2=55&wheelsize2=15&tirediameter2=23.44&maxrpm2=8400&finaldrive2=4.4&gearratioa=3.23&gearratiob=2.105&gearratioc=1.458&gearratiod=1.107&gearratioe=0.848&gearratiof=0&trannytype=

Work necessary for each set:

#1) Take gear stack and put it on different final drive. Reinsert into original case.
#2) Remove entire guts from one transmission case, dump into another
#3) Remove guts from two transmissions, take 2nd gear from one trans, 1, 3, 4, and 5 and final drive from other. Insert whole mess into case from trans that donated 2nd gear.

Which one would you run and why? Car is making ALLOFIT power, is FWD, and traction is an issue.

Mmmmmmmmmm such formatting.

It's the #

i removed them and it still seems to hate me.

All fixxored meow.

Very good, thank you! #now which transmission should i use?

Looks like only one of them will get you over 100 in third gear. I'd choose that one.

Without knowing more specifics, I like the rpm drops and mph increments best on #1.

That is a consideration.

Other considerations/observations:

1) Trans 2 seems to be the most linear in general, for better or for worse

2) Trans 1 looks like it would be the most traction-worthy, though i'm unsure how much difference 5mph in 2nd REALLY makes in terms of traction. Would be worth a bit in an autox scenario, though. Gearing drops are kindof a mess, however, the 3-4 shift looks awesome in a "holy E36 M3 hold the berkeley on" kind of way.

Transmission 3 looks like it might be the best possible of all worlds, but i'm really wondering if it's worth all the extra work over the other two options just really for an extra 5mph in 2nd gear, though it does look like it gets my 3rd gear starting RPM the highest, which again... for better or for worse when attached to a motor that makes a crapload of grunt in the midrange.

Just musing out loud. Never really had the opportunity to pick and choose like this.

EastCoastMojo wrote: All fixxored meow.

Driven5 wrote: Without knowing more specifics, I like the rpm drops and mph increments best on #1.

Sorry, i get in the habit of being a little cagey from time to time. The car will be plenty capable of reaching the gearing limited top speed shown in those figures, and makes more torque than horsepower. FWD means traction is a serious issue.

If traction is an issue at the speeds you plan on playing at, gearing does not matter. What does it matter what 2nd gear is if you have to soft pedal it in 3rd?

Me, I'd look at the tooth counts and choose the coarsest gears available. Coarse gears are stronger, as they are more tolerant of the shafts spreading apart.

Knurled wrote: If traction is an issue at the speeds you plan on playing at, gearing does not matter. What does it matter what 2nd gear is if you have to soft pedal it in 3rd? Me, I'd look at the tooth counts and choose the coarsest gears available. Coarse gears are stronger, as they are more tolerant of the shafts spreading apart.

Well... it could matter, no? Shorter gearing = higher effective gear multiplied torque, right? I'm not sure that 5mph difference in "length" will matter much in the end in terms of traction, but it's just something i'm thinking about.

Speaking from a traction limited perspective, shorter gears just mean you blow through faster. Taller gears give you a little more room to breathe.

Perversely, when you have too much power, you want CLOSER gears as well, so you don't get into a situation where you blow the tires away, then upshift into a gear where you can't, and suddenly you're going from 7000rpm and light throttle to 2500rpm and buuuuuuuhhhhhhh.

Basically there's a happy zone where you find a gear that is tall enough to not totally blow away but short enough to be useful. All that said, I have found that 5-10% differences in ratio mean very little in the real world. At the ratios you're thinking of, don't sweat it too terribly much and just pick your first, pick your fifth, and make the gaps in between decent.

So you would vote option 2? Strength will be a wash between all options.

I'd vote to E36 M3can the engine and build something with a longer powerband. Higher revving engines are easier to drive in low traction situations.

Not an option. Motor has a huge powerband. 4000ish rpms. Not interested in changing it, nor can I.

I'm asking for input on transmission options. I have all the ratios in all tjose transmissions available to me, as well as a 4.10 final drive i'm not interested in using.

Let's not bring the GRM Factor into the very focused question, shall we?

Unfortunately you'll never know for sure until you try it, but for what it's worth here is how I would analyze it...

Option 1: The MPH spacing is 32, 34, 31, and 41. The "shift point" RPM spacing is 809, 644, and -30.

Option 2: The MPH spacing is 27, 29, 35, and 48. The "shift point" RPM spacing is 675, 274, and -47.

Option 3: The MPH spacing is 32, 24, 34, and 48. The "shift point" RPM spacing is 1283, -68, and -47.

In an ideal world, I like to see a consistent pattern in the numbers. This immediately kills #3 for me. Option #2 definitely has the most consistent pattern on both fronts, and would probably be a good choice in that regard. Factoring in my recollection of your dyno plot from the shift point thread and the associated speed potential, since Option #1 has a reasonable pattern AND has the tallest ratio available in every gear, then I would think it might actually suit your power band the best. Partially because of the massive torque in general, and partially because I wouldn't be surprised if you find yourself fastest by short shifting into gears 3, 4, and 5 most of the time. But that's all just analytical speculation. Since 1st and 5th are the same on all, consider the main use(s) of the car and how gears 2, 3, and 4 would work with it. I tend to look for top speeds in gears which would eliminate extra shifting into a gear for just a brief period of time before shifting back down again (autox/road course) or crossing the finish line (drag).

Swank Force One wrote: Not an option. Motor has a huge powerband. 4000ish rpms. Not interested in changing it, nor can I.

No worries. One of my cars has a 1200rpm window of opportunity (calling it a "power band" is a bit optimistic) and the other one has 8000rpm of useful powerband and both of them like closer gears.

The gear spreads you posted are all far too wide and your engine has low enough inertia that you won't have to worry about the gears being too close. A good rule of thumb I like is that first gear should be good to 40ish, top gear should redline out around 110, and life will be good.

Top gear redlining around 110mph would suck hard at the 1/4 mile drag strip, let alone the standing mile. I've already trapped 118mph in this car using Transmission #1, but with a 4.10 final drive, with far less power.

Looking for a 130mph trap out of the car in the 1/4 as a "goal." Anything around 125mph will satiate me.

After mulling it over some more and taking input across various sites, seems the overwhelming majority prefers #1, and despite my OCD levels of desire for linear things with identical RPM drops, i have to agree that from a performance perspective, it's the one to go with.

You do not want identical RPM drops! The gears should get closer together as you go faster, since you'll be through the first couple gears quickly (if not just plain up in smoke) and the final three are the critical ones.

130mph? What would you wanna go that fast for? Maybe try to hit 110 in the 1/8th and then coast the rest of the way...

This car sucks in the 1/8th haha. It's a big end car only.

Ask Dansxr2 how hard I ran him down after he took me through the 1/8th. And that was probably making half the power i'm going to now. It'll never launch worth a damn unless I put wrinkles on it.

I'll vote for #1, for what you're doing.

Ok now.... someone cheerlead me well enough to make me feel confident about building this monstrosity myself. Never done transmission work before.