93Euphoria

So I finally picked up my buddies T56. 70k miles on it. Still have to get all the supporting accessories for it. Question is as far as the top end how much would it effect my top end climb with 3.23 vs 3.73’s? Once the tranny is in it will mainly be a DD, Grand Tourer, and occasionally a track car during the weekends.

BTW what are your 80mph RPM’s with whatever gear your running?

devildog214

stock 3.42s in 6th at 80 is about 1700ish? I would definitely want to upgrade the 3.23's for atleast stock 6sp gears since you can find those used for cheap. 3.73 is the middle of the road choice for 6sp. Me personally I was thinking about going 4.10 mainly because there's not a speed limit over 65 in nj and its kind of pointless cruising at 85 at 1900rpm. Not to mention the performance gains from it. Also theres a speed calculator you can type in your tire height, gear ratios for your year t56 and it will give you your mph at that speed, in that gear, etc.

bufmatmuslepants

iTrader: (3)

Mine with 3.42s stock 76mph was 2000, 80 was definately not 1700.

SS RRR

iTrader: (2)

www.f-body.org/gears

devildog214

muslepants really? I did look at my build sheet and I do have 3.42s and the car has been in my family since new. Seriously even at 85 mph my rpms are still just under 2000.

abates

1993 models came with a transmission that has different ratios than those of 1994 and later years.

My 1993 had the following

1st 2.97 to 1
2nd 2.07 to 1
3rd 1.43 to 1
4th 1 to 1
5th 0.80 to 1
6th .62 to 1

There is another 1993 model transmission that has a 3.36 1st gear with different 2nd and 3rd (I can't remember the ratios) gears than mine as well.

One of them is a M28 and the other is M29.

Hope this helps.

devildog214

ah true i totally forgot his was a 93, but he didn't mention what year is his buddys t56.

bufmatmuslepants

iTrader: (3)

Mines a 94, and was bone stock when I bought it but who knows maybe it did have gears, I'm putting in another stock 10 bolt this week that I KNOW has 3.42s so well see. I do know with 4.33s it was over 3000, said I was doing 90 but was really doing 65. That sucked *** on the highway but was perfect at the track as 4th ended at 113 and that's what I trap.

93M6Formula

If running a '93 M29 T-56, go with 3:73s.
If running a '94+ MN6 T-56, go with 4.10s.

multmigs

iTrader: (2)

where is the info on the trans itself about what version it is? i have a used t56 that i bought out of a car that was wrecked and i did not confirm the year ever?

abates

The 1993 M6's are either a M28 or a M29 and can shift 1st thru 4th at part throttle without a skip shift eliminator.

The 1994 and later M6's need a skip shift eliminator in order to shift 1st thru 4th at part throttle. These also have a 0.5 6th gear ratio. You can check it by turning the output shaft one complete turn while the input shaft would only turn 0.5 times. Be precise tho, the 1993 M6's have a 0.62 6th gear ratio which is close and can be mistaken for 0.5 if not watched closely.

93Euphoria

A4 with 2.73 you would think that is economical gears but in reality its killing mileage (not that I really give a rats A$$) and is a turd down low. At 80 im at roughly 2600-2700rpm. I also curious to find what I speed trap in 5th & 6th. I hear on these tranny’s we go faster in 5th. I do a lot of highway driving and im looking for a gear that has good accel with a good top end, not too low where it kills bang shifting and not too high to where I would be spinning 3000rpms at 80-90mph.

Came out of my buddies wrecked 01 TA. Someone side swiped him (drunk driver). He rebuilt it back in 07 and put 70k on it in only 6 years. Looks in good condition. Only concern is what clutch options to look at, aswell as getting an aluminum DS or use the stock iron one.

An 02 that was rebuilt. im sure those years were the MN6 which im curious what gear ratios are in them.

BALLSS

the MN6 has a .50 6th gear. My T56 has it and at 80 mph with a 27" tire I tach just under 2k RPM. 4 speed on the street and 1/4. 5th in traffic on fwy. 6th if going above 65mph...unless you want to be at 1400-1500 rpm in 6th at 65

as mentioned there are gear/rpm calculators you enter tranny type, tire size and rear end gears to get RPM

devildog214

so you got an 01 so you need to find an lt1 bellhousing as well as a lt1 flywheel and clutch if you didnt know already.

Using the gear calculator 4.10s with a 01 trans at 85mph your looking at 2300 in 6th, not terrbile. Me personally since my exhaust gets a bit loud after 2000 or so to comfortably cruise I would want to be around 70mph and 1900rpms with 4.10s. That's something that I consider maybe your exhaust isn't that loud.

guppymech

iTrader: (7)

The input shaft on the '01 T56 is not the correct length for a LT1, you'll need to change that to the shorter one that was used on our cars.

93M6Formula

This ^^ Input shaft, bellhousing, clutch assembly, LT1 hydraulics, etc etc.

A '93 M28 or M29 T-56 will not have CAGS solenoid on the side of the trans.

93Euphoria

Thanks guys. Anyone have these these part number by chance? In the meantime ill start some searches. This car im actually building for the standing mile, pro touring, grand touring. Hate to ask the 1/4 mile guys what there top speed with there gears regardless of there power output (wanting to know the potential of these LT1’s & there aerodynamics vs the LS head light style), but what are your top speeds? Just curious to know your numbers.

Heres a copy of stock speeds, but seems off (assuming not enough power at lower & higher rpms why we wont run any of these speeds with our stock 4L60E gear ratios.

1st: 3.06
2nd: 1.76
3rd: 1.00
4th: 0.70



Gear: 1st 2nd 3rd 4th
RPM
500 5 8 14 20
600 5 10 17 24
700 6 11 20 28
800 7 13 22 32
900 8 14 25 36
1000 9 16 28 40
1100 10 17 31 44
1200 11 19 33 48
1300 12 21 36 52
1400 13 22 39 56
1500 14 24 42 60
1600 15 25 45 64
1700 15 27 47 68
1800 16 29 50 72
1900 17 30 53 76
2000 18 32 56 80
2100 19 33 59 84
2200 20 35 61 88
2300 21 36 64 92
2400 22 38 67 96
2500 23 40 70 100
2600 24 41 72 104
2700 25 43 75 108
2800 26 44 78 111
2900 26 46 81 115
3000 27 48 84 119
3100 28 49 86 123
3200 29 51 89 127
3300 30 52 92 131
3400 31 54 95 135
3500 32 55 98 139
3600 33 57 100 143
3700 34 59 103 147
3800 35 60 106 151
3900 36 62 109 155
4000 36 63 111 159
4100 37 65 114 163
4200 38 67 117 167
4300 39 68 120 171
4400 40 70 123 175
4500 41 71 125 179
4600 42 73 128 183
4700 43 74 131 187
4800 44 76 134 191
4900 45 78 137 195
5000 46 79 139 199
5100 46 81 142 203
5200 47 82 145 207
5300 48 84 148 211
5400 49 86 151 215
5500 50 87 153 219
5600 51 89 156 223
5700 52 90 159 227

moderate Z28

It cant be right. It says my car will run 200 mph at 6,000 RPM in 5th, and 299 mph in
6th.

devildog214

aerodynamics? You would think since all 4th gens are very pointy and straight as a pencil they have good aerodynamics, but you'd be wrong. You look at fbody cars and they have alot of front end lift, (aka Flash's WS6) these speeds are way higher than any 1/4 trap speed. Going to be hard to tell what car has better aero just by trap speeds since well, they're different motors. If you want aerodynamics for super high speeds a corvette will be better suited How fast do you plan to run that aerodynamics will be an issue? As far as improving aerodynamics on both an LT or LS body there alot of aero thats just for show, but theres probably a few companies out there making stuff to keep the air from lifting the front end at high speeds.

93M6Formula

Tire size has to be in the equation too.

Use this calculator.
http://www.csgnetwork.com/multirpmcalc.html