whats better T-56 with 373's or 410's?
04-13-2010, 09:39 PM
#41
and you realize he has a stock 10 bolt with a simple bolt on, near-stock car dont you?
All you people preaching low low low gears must not realize how little difference it really makes.
The LOWEST you can go is 4.56 with a 10 bolt and I wouldn't trust those to last long enough for a drive around the block.
If he had a 9 inch, 12 bolt, s60 etc then yes go with a low gear from hell, but it would be nice if someone would give him some PRACTICAL advice.
In a 10 bolt, 4.10 is as low as you ever want to go, and as said before they WILL break in a stock 10 bolt.
3.73 3.90 and 4.10 probably wont make 1/10 of difference between them. I would personally rather have the gear that's the strongest...
I went to 3.90 when my 4.10's broke and if those break before I build a stronger rear then I will go up to 3.73...
04-13-2010, 11:23 PM
#43
really now? 3.42 to 4.10 is roughly a 20% difference, its fair to say his speedo will be off roughly 20%. i don't know how my blanket statement doesn't work here about shorter gears being quicker. You don't see many drag cars running 2.56s. I make more torque at 2500 rpm than most H/C 350s ever will at peak, but 4.71 are still a hell of a lot better (quicker) than the 4.11s I had. Then again, this is the lt1 section of ls1tech, where the bolt on guys know everything.
04-14-2010, 02:40 AM
#45
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If the op wants this performance for 1/4 racing then op should decide what gear is best depending on where power peak will be when crossing the traps. If this is for street use then get whatever gear makes op feel good. Here's a page that has helped me out many times: www.f-body.org/gears
Badass. Brings a tear to my eye. 
Best part of cruising there back in the day was being able to sit in the middle, watch cars go by and holler at the ladies.
Best part of cruising there back in the day was being able to sit in the middle, watch cars go by and holler at the ladies.
04-14-2010, 03:06 AM
#46
My car reads 10mph fast..... 3.42 - 4.10
I dont care if the 4.10s break,my car likes that gear,performs well with that gear and now just over a year i have a problem with my rear. I do have an 8.8 on the fabricator block, almost ready to go in my car and the 8.8 is loaded with 4.10s...It hits the races with 26" hoosier 275/50/15 DRs or Nitto 245/50/16s and when the bottle goes back in 28" DRs will be on to keep me from having to grab 5th across the stripe...If you are worried about breaking the F-10bolt leave it alone 3.42s are fine!
I dont care if the 4.10s break,my car likes that gear,performs well with that gear and now just over a year i have a problem with my rear. I do have an 8.8 on the fabricator block, almost ready to go in my car and the 8.8 is loaded with 4.10s...It hits the races with 26" hoosier 275/50/15 DRs or Nitto 245/50/16s and when the bottle goes back in 28" DRs will be on to keep me from having to grab 5th across the stripe...If you are worried about breaking the F-10bolt leave it alone 3.42s are fine!
04-14-2010, 08:52 AM
#47
For the guys with gears and 10 bolts, what gear and at what rpm are you in going past the 1/8th and 1/4? Im already trapping 85 in the 1/8th, and 3rd with the 3.42s winds out around 93mph at 6000rpm. This would give 85.3mph with 3.73s, 81.5 with 3.90s, and 77.6 with 4.10s. 4th winds out around 125 with 3.42s, which is 114.6 with 3.73, 109 with 3.90s, and 104 with 4.10s. Gears should also gain you some mph at the end of the track, even if it is just 1. Going by those numbers with any gear upgrade you have to shift to 4th in the 1/8th, unless you dont mind smacking the rev limiter crossing the line with 3.73s in 3rd. And assuming a stock gear bolt on car will trap at most 110, 4.10s would cause you to use 5th in the 1/4. 3.90s look like they would be ideal for a bolt on car at the track, as many posters have already said.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
04-14-2010, 09:00 AM
#48
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For the guys with gears and 10 bolts, what gear and at what rpm are you in going past the 1/8th and 1/4? Im already trapping 85 in the 1/8th, and 3rd with the 3.42s winds out around 93mph at 6000rpm. This would give 85.3mph with 3.73s, 81.5 with 3.90s, and 77.6 with 4.10s. 4th winds out around 125 with 3.42s, which is 114.6 with 3.73, 109 with 3.90s, and 104 with 4.10s. Gears should also gain you some mph at the end of the track, even if it is just 1. Going by those numbers with any gear upgrade you have to shift to 4th in the 1/8th, unless you dont mind smacking the rev limiter crossing the line with 3.73s in 3rd. And assuming a stock gear bolt on car will trap at most 110, 4.10s would cause you to use 5th in the 1/4. 3.90s look like they would be ideal for a bolt on car at the track, as many posters have already said.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
04-14-2010, 11:33 AM
#49
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bufmatmuslepants--- maybe my tires throw this off or something but i trapped 109 with the potiential to trap a little more. just made one pass and done. but i was in the top of 4th at 5500 with 4.10s. now i run a nitto 555r 315/35R17 which i think is like 25.79 inches. bolt ons and a baby cam. soon to swap out LTs instead of Mids.
04-14-2010, 11:54 AM
#50
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For the guys with gears and 10 bolts, what gear and at what rpm are you in going past the 1/8th and 1/4? Im already trapping 85 in the 1/8th, and 3rd with the 3.42s winds out around 93mph at 6000rpm. This would give 85.3mph with 3.73s, 81.5 with 3.90s, and 77.6 with 4.10s. 4th winds out around 125 with 3.42s, which is 114.6 with 3.73, 109 with 3.90s, and 104 with 4.10s. Gears should also gain you some mph at the end of the track, even if it is just 1. Going by those numbers with any gear upgrade you have to shift to 4th in the 1/8th, unless you dont mind smacking the rev limiter crossing the line with 3.73s in 3rd. And assuming a stock gear bolt on car will trap at most 110, 4.10s would cause you to use 5th in the 1/4. 3.90s look like they would be ideal for a bolt on car at the track, as many posters have already said.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
The other side is cruising rpm and speedo. 80mph is about 2000rpm in 6th with 3.42s. Thats 2180 with 3.73s, 2280 with 3.90s, and 2400 with 4.10s. When doing 80mph, an uncorrected speedo with 3.73s would say 87, 3.90s would say 91.2, 4.10s would say 96.
This isn't right - you've mis-calculated somewhere, or, if you're using your actual car, you tach/speedo are way off. A stock 94-97 M6 car with 3.42's will go 98 mph at 5700rpm in third, and 127mph in 4th. Spinning to 6000rpm (must have a tune, because stock limiter stops you before then) will get you 103mph in 3rd, and 134 in 4th. This is right on with what I've seen in my car, I was shifting to 4th on the strip at about the 1000' mark at about 5600rpm, and just getting into 4th before crossing the line at 102-103 mph.
Also, cruising with stock 3.42's you should only be turning 1800rpm at 80mph, 2000rpm at 90mph.
Bufmatmusclepants - you have 3.73s if you doing 93mph @ 6000rpm in third. Your cruise RPM statements reflect 3.73s as well. Not the stock rear you thought it was.
Proace4- your numbers look right on for a 4.10's car, and right about where you'd want to be rpm wise with a mild cam.
Going to a 4.10, even on a stock car, is ideal. Assuming a bolt on car that likes to be shifted around 5800-5900rpm, you'd hit 4th at about 84mph, and then cross the lines at about 106mph and 5700rpm. Even as you mod up, 4.10's stay right where you want them, assume you move up to a mild cam/mild head work car, and put down some good numbers with a good pull all the way through 6300rpm - enough power to trap like 114. 4.10's would have you crossing the line at 6100rpm - right in about where you want to be. 3.90's might get you even closer to your ideal rpm on the big end, but we all know the 60' is where its at for the ET, and the 4.10's are really gonna help you there with a cam/bolt on car.
Last edited by acammer; 04-14-2010 at 12:09 PM.
04-14-2010, 01:00 PM
#51
I know the mph is not exact, the factory tach is off on these cars, and looking down for a split second and seeing the needle at 6 is where I shift, and its somewhere past 5000 when I cross the traps at 85. If you have the actual numbers, plug them into the equation. Put in whatever actual mph you think your going at whatever rpm for X, and solve for Y and youll get your speed at the same rpm with a different gear ratio. I put 93mph which is my guess where 6000rpm is, so if you say its 97, put 97 and youll get your speed at a given rpm for different gears.
3.42 * Xmph = 3.73 * Ymph gives speed for gears
3.42 * Xmph = Y
3.73
3.42 * 93 = 85.3
3.73
or to see what rpms youd be turning in the same transmission gear at X mph that you cross the line with steeper gears,
6000rpm = X rpm / 4.10
3.42
4.10 * 6000 = 7192 rpm
3.42
My car is actually at just over 2000rpm at 80 according to my factory tach, 77 is closer to 2000rpm. Im running 245/50R16 sumikomos, about half tread at 30psi. The car was bone stock down to the paper filter when I got it, but that doesnt mean one of the previous owners didnt blow the rear and replace it with 3.73s or something. My GPS is almost dead on with my speedo tho, so maybe my tach is 200rpm fast.
3.42 * Xmph = 3.73 * Ymph gives speed for gears
3.42 * Xmph = Y
3.73
3.42 * 93 = 85.3
3.73
or to see what rpms youd be turning in the same transmission gear at X mph that you cross the line with steeper gears,
6000rpm = X rpm / 4.10
3.42
4.10 * 6000 = 7192 rpm
3.42
My car is actually at just over 2000rpm at 80 according to my factory tach, 77 is closer to 2000rpm. Im running 245/50R16 sumikomos, about half tread at 30psi. The car was bone stock down to the paper filter when I got it, but that doesnt mean one of the previous owners didnt blow the rear and replace it with 3.73s or something. My GPS is almost dead on with my speedo tho, so maybe my tach is 200rpm fast.
04-14-2010, 01:36 PM
#52
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You're definitely missing something somewhere - you're not going to turn 6000rpm on a stock PCM, and if you'd did you'd be going over 100mph with stock gears and tire sizes. 200rpm fast or more high on the stock tach is extremely common, but if your speedo is right on, if you take it right to the limiter at 5800rpm (6000rpm indicates minus ~200rpm of tach error) you'd have 91mph in third with a 3.73 rear. 3.42's would be 100mph even. 6000rpm (acutal, would require a modified PCM) would take you to 94mph w/ 3.73's, 103mph with 3.42's.
Assuming your speedo is about right, which your GPS confirms, and your stock tach reads about 200rpm high, which is pretty much the norm, I think you're sporting 3.73s.
Your math is ok, but you're starting with bad data, so you're just getting more bad data. Check out www.f-body.org/gears. Play with that some, I think you'd like it. And it'll give you a better idea of what the stock gearing is like, and what gear changes will do to these cars.
Assuming your speedo is about right, which your GPS confirms, and your stock tach reads about 200rpm high, which is pretty much the norm, I think you're sporting 3.73s.
Your math is ok, but you're starting with bad data, so you're just getting more bad data. Check out www.f-body.org/gears. Play with that some, I think you'd like it. And it'll give you a better idea of what the stock gearing is like, and what gear changes will do to these cars.
04-14-2010, 02:54 PM
#54
I know i am not trusting the factory tach nor the speedo however,my M6 car runs Nitto 245/50/16s (26.1) with 4.10s and have yet to hit the limiter crossing the stripe. Ion set my limiter to 6ooo rpm. Trap speed according to time slip is 105.20 @3000'DA
The stock 3.42s and same size DRs i hit the 5800rpm limiter (NO TUNE) in 3rd gear just after the stripe.
The stock 3.42s and same size DRs i hit the 5800rpm limiter (NO TUNE) in 3rd gear just after the stripe.
04-14-2010, 11:29 PM
#55
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You're definitely missing something somewhere - you're not going to turn 6000rpm on a stock PCM, and if you'd did you'd be going over 100mph with stock gears and tire sizes. 200rpm fast or more high on the stock tach is extremely common, but if your speedo is right on, if you take it right to the limiter at 5800rpm (6000rpm indicates minus ~200rpm of tach error) you'd have 91mph in third with a 3.73 rear. 3.42's would be 100mph even. 6000rpm (acutal, would require a modified PCM) would take you to 94mph w/ 3.73's, 103mph with 3.42's.
Assuming your speedo is about right, which your GPS confirms, and your stock tach reads about 200rpm high, which is pretty much the norm, I think you're sporting 3.73s.
Your math is ok, but you're starting with bad data, so you're just getting more bad data. Check out www.f-body.org/gears. Play with that some, I think you'd like it. And it'll give you a better idea of what the stock gearing is like, and what gear changes will do to these cars.
Assuming your speedo is about right, which your GPS confirms, and your stock tach reads about 200rpm high, which is pretty much the norm, I think you're sporting 3.73s.
Your math is ok, but you're starting with bad data, so you're just getting more bad data. Check out www.f-body.org/gears. Play with that some, I think you'd like it. And it'll give you a better idea of what the stock gearing is like, and what gear changes will do to these cars.
Hey man--- i played with that calculator and it wasnt making since till i switched my tranny to the 93 model. once i put in the 4.10s, it all started to make sense. how do you know what version of the t56 is in your car? any cast numbers or stamps I can look up?
04-16-2010, 11:10 AM
#56
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There are so many factors that make this comparison change between the two sets of gears. In the end it matters about your setup and how far you have gone with the setup/power/cam/tire size compound/weight.
I bought 4:10 gears for my mild cam only setup for a street driven car a long time ago (10yrs). The gears were much more responsive than stock 3:42 setup in an m6. If you had decent street tires you gripped well if you were carefull with 1st gear and how you clutched into it. (You cant dump it with stock 10 bolt and sticky tires and make the 10 bolt live.) I occasionally caught myself starting in 2nd or going 1st to 4th to save gas. The extra gear was there when I wanted it.
If I had to do it all over I would save the $$ and start with a stronger rear end housing to begin with. This will let you dump with steep gears and not have to worry as much.
I bought 4:10 gears for my mild cam only setup for a street driven car a long time ago (10yrs). The gears were much more responsive than stock 3:42 setup in an m6. If you had decent street tires you gripped well if you were carefull with 1st gear and how you clutched into it. (You cant dump it with stock 10 bolt and sticky tires and make the 10 bolt live.) I occasionally caught myself starting in 2nd or going 1st to 4th to save gas. The extra gear was there when I wanted it.
If I had to do it all over I would save the $$ and start with a stronger rear end housing to begin with. This will let you dump with steep gears and not have to worry as much.
04-16-2010, 10:44 PM
#57
this is better than an episode of jersey shore and the hills combine!...I love how dramatic it gets in here sometimes
and the name calling takes me back to the Jr. High days...seriously, if somebody disagrees with you so what? what difference does it make? share your opinion and experiences and move on...
04-17-2010, 08:04 AM
#58
When i did the t56 swap with 4.10s i didnt really loose any mpg other then in the city driving which is normal. Ive bolton 3.42s and 3.73 cars and to tell you the truth 4.10s are the way to go. Revs up alot faster from a dig and probubly one of the most seat of the pant gains you will get other then doing a cam swap and beyond. Makes it alot of fun to drive even for a lightly modified car and still get as good mileage as a 3.42 rearend or a 2.73 a4 car would. So in all honesty why settle for less and have the same mileage???
4.10s!
4.10s!
