Need some serious help understanding final drive ratio
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Need some serious help understanding final drive ratio
Evening all,
I know this is the coupe side (ugh...jk! lol) but I know more of you are significantly more knowledgeable (
) in terms of modifications. In particular, I have a good friend wanting to do a rear differential swap at the moment. His N/A 350Z (HR) was somewhat of a dedicated track car. He did gearing (sorry, I don't know the terminology) of some sort that made his final gear 4.083 (~4.10). His trap speed was significantly higher at the track. I unfortunately don't have details, but he's convinced me to do a swap; I trust the guy, but I'm uneasy because I don't UNDERSTAND ANY OF IT. From the research that I've done, the 6MT FD on the sedans is 3.69. So...for every revolution that the transmission makes, the rear tires spin 3.69 times? So with the new gears, 1 revolution = 4.10 turns in the back? He had a machine shop install all the goods, etc. (opened up rear differential and some other crazy stuff...he lost me in the description). He's selling his car - mentioned that they were forged, etc.. Since the install = $$$, he came to the conclusion that we would instead just swap out our rear differentials. A little concerning since he's EXTREMELY hard on his car (tracked), but only has 23k miles on it (7k on 4.08 gears), versus my 28k. Would really, really appreciate any sort of explanation. I've been told the rear differentials on the 2007-08 HR 350Z's are a little bit better than the ones on our G37's (some value that's 0.5 versus our 0.7)...?
ANY sort of explanation, would be EXTREMELY helpful. THANKS GUYS!!!
Eric
I know this is the coupe side (ugh...jk! lol) but I know more of you are significantly more knowledgeable (
) in terms of modifications. In particular, I have a good friend wanting to do a rear differential swap at the moment. His N/A 350Z (HR) was somewhat of a dedicated track car. He did gearing (sorry, I don't know the terminology) of some sort that made his final gear 4.083 (~4.10). His trap speed was significantly higher at the track. I unfortunately don't have details, but he's convinced me to do a swap; I trust the guy, but I'm uneasy because I don't UNDERSTAND ANY OF IT. From the research that I've done, the 6MT FD on the sedans is 3.69. So...for every revolution that the transmission makes, the rear tires spin 3.69 times? So with the new gears, 1 revolution = 4.10 turns in the back? He had a machine shop install all the goods, etc. (opened up rear differential and some other crazy stuff...he lost me in the description). He's selling his car - mentioned that they were forged, etc.. Since the install = $$$, he came to the conclusion that we would instead just swap out our rear differentials. A little concerning since he's EXTREMELY hard on his car (tracked), but only has 23k miles on it (7k on 4.08 gears), versus my 28k. Would really, really appreciate any sort of explanation. I've been told the rear differentials on the 2007-08 HR 350Z's are a little bit better than the ones on our G37's (some value that's 0.5 versus our 0.7)...? ANY sort of explanation, would be EXTREMELY helpful. THANKS GUYS!!!
Eric
Last edited by eksigned; Apr 27, 2011 at 03:09 AM.
Sooooo.....let me get this straight. You have no idea whats going on but you green lighted the project? Ummm yeah right. You sound like my boss.
Well in any event I've got a bridge for sale, intrested? LOL, Good luck with that one.
Well in any event I've got a bridge for sale, intrested? LOL, Good luck with that one.
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From: Toronto, Canada
Evening all,
I know this is the coupe side (ugh...jk! lol) but I know more of you are significantly more knowledgeable () in terms of modifications. In particular, I have a good friend wanting to do a rear differential swap at the moment. His N/A 350Z (HR) was somewhat of a dedicated track car. He did gearing (sorry, I don't know the terminology) of some sort that made his final gear 4.083 (~4.10). His trap speed was significantly higher at the track. I unfortunately don't have details, but he's convinced me to do a swap; I trust the guy, but I'm uneasy because I don't UNDERSTAND ANY OF IT. From the research that I've done, the 6MT FD on the sedans is 3.69. So...for every revolution that the transmission makes, the rear tires spin 3.69 times? So with the new gears, 1 revolution = 4.10 turns in the back? He had a machine shop install all the goods, etc. (opened up rear differential and some other crazy stuff...he lost me in the description). He's selling his car - mentioned that they were forged, etc.. Since the install = $$$, he came to the conclusion that we would instead just swap out our rear differentials. A little concerning since he's EXTREMELY hard on his car (tracked), but only has 23k miles on it (7k on 4.08 gears), versus my 28k. Would really, really appreciate any sort of explanation. I've been told the rear differentials on the 2007-08 HR 350Z's are a little bit better than the ones on our G37's (some value that's 0.5 versus our 0.7)...?
ANY sort of explanation, would be EXTREMELY helpful. THANKS GUYS!!!
Eric
I know this is the coupe side (ugh...jk! lol) but I know more of you are significantly more knowledgeable (
) in terms of modifications. In particular, I have a good friend wanting to do a rear differential swap at the moment. His N/A 350Z (HR) was somewhat of a dedicated track car. He did gearing (sorry, I don't know the terminology) of some sort that made his final gear 4.083 (~4.10). His trap speed was significantly higher at the track. I unfortunately don't have details, but he's convinced me to do a swap; I trust the guy, but I'm uneasy because I don't UNDERSTAND ANY OF IT. From the research that I've done, the 6MT FD on the sedans is 3.69. So...for every revolution that the transmission makes, the rear tires spin 3.69 times? So with the new gears, 1 revolution = 4.10 turns in the back? He had a machine shop install all the goods, etc. (opened up rear differential and some other crazy stuff...he lost me in the description). He's selling his car - mentioned that they were forged, etc.. Since the install = $$$, he came to the conclusion that we would instead just swap out our rear differentials. A little concerning since he's EXTREMELY hard on his car (tracked), but only has 23k miles on it (7k on 4.08 gears), versus my 28k. Would really, really appreciate any sort of explanation. I've been told the rear differentials on the 2007-08 HR 350Z's are a little bit better than the ones on our G37's (some value that's 0.5 versus our 0.7)...? ANY sort of explanation, would be EXTREMELY helpful. THANKS GUYS!!!
Eric
Yeah ... thats right... 350Z HR something... sedan something else.. sounds about right...
sounds like you guys just want to spend some money on unnessisary shet... nothing seems to be broken on your car.. so i really cant see why you would want to do this... unless you track your sedan! Sure there is gas savings... but how much gas can you buy with the money you will spend on instal?
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Yeah ... thats right... 350Z HR something... sedan something else.. sounds about right...
sounds like you guys just want to spend some money on unnessisary shet... nothing seems to be broken on your car.. so i really cant see why you would want to do this... unless you track your sedan! Sure there is gas savings... but how much gas can you buy with the money you will spend on instal?
sounds like you guys just want to spend some money on unnessisary shet... nothing seems to be broken on your car.. so i really cant see why you would want to do this... unless you track your sedan! Sure there is gas savings... but how much gas can you buy with the money you will spend on instal?
Here's a discussion that was on here before about the 4.08 final gear https://www.myg37.com/forums/engine-...drive-omg.html
lower gas mileage
faster 0-60
lower top speed
lower gas mileage
faster 0-60
lower top speed
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In a very small nutshell, changing your final gear to a shorter gear (bigger number) will increase your acceleration in every gear. It will also proportionately decrease your overall top speed and the top speed that you can reach in each gear. It will have a negative effect on your MPG, particularly on the highway since your engine will be turning more RPM at a given speed than before the swap.
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I've done a bit more reading on the matter, I see what's going on now 
.Yeah ... thats right... 350Z HR something... sedan something else.. sounds about right...
sounds like you guys just want to spend some money on unnessisary shet... nothing seems to be broken on your car.. so i really cant see why you would want to do this... unless you track your sedan! Sure there is gas savings... but how much gas can you buy with the money you will spend on instal?
sounds like you guys just want to spend some money on unnessisary shet... nothing seems to be broken on your car.. so i really cant see why you would want to do this... unless you track your sedan! Sure there is gas savings... but how much gas can you buy with the money you will spend on instal?
Install = $0
Here's a discussion that was on here before about the 4.08 final gear https://www.myg37.com/forums/engine-...drive-omg.html
lower gas mileage
faster 0-60
lower top speed
lower gas mileage
faster 0-60
lower top speed
seriously! ****in' a s s holes! jk
lol i don't blame 'em...i would've said the same thing(s) hahaha
In a very small nutshell, changing your final gear to a shorter gear (bigger number) will increase your acceleration in every gear. It will also proportionately decrease your overall top speed and the top speed that you can reach in each gear. It will have a negative effect on your MPG, particularly on the highway since your engine will be turning more RPM at a given speed than before the swap.
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