4.08 Final Drive = OMG
His gears make him fast, how fast i dont know, faster than any n/a G37's i've been in, how fast is that? I don't know, but I DO KNOW if he keeps testing his gears out in Beaverton he will get a ticket.
I grew up on American muscle cars and pony cars. I've run everything from 2.73, 3.08, 3.55, 3.73, to 4.10 in my Mustangs alone. I've swapped ring and pinion gears by myself and properly set the back lash. It seems to me that most of the people who post in this forum don't have that kind of background or experience with basic performance mods that involve gearing.
That said, I'd personally NEVER change the final drive in the G37. A lot of guys here who don't understand gearing probably won't realize that there are penalties to pay for the greater leverage you get from more aggressive gearing. To me, it's just not worth it in a car like the G37. If you're talking about a track car, then fine...that might be worth it. But a street car? No thanks.
So what's wrong with changing the gearing? Well, not only will your fuel economy suffer (all else equal), but even more importantly, your car will forever be revving at a higher RPM. I like the fact that 6th gear is very much overdriven to the point that the car just hums along easily and quietly at highway speeds. My old 5.0L Mustang came with 2.73 gears and the car felt much more alive after I swapped in a set of 3.55 gears. But long highway trips sucked because the car was noisy due to the fact that the engine was now at a substantially higher RPM in every gear, including overdrive. It was fun zipping around town, but highway trips became something that I'd avoid. Another thing I like about the G37 is the long pulls between gear changes. Our engines aren't exactly high revving engines, but with the stock gearing the car pulls for a fairly long time between shifts. That's something that will change to some extent by swapping in more aggressive gears. I don't know, I just think of my G37 as more of a grand touring car than a stoplight racer. I'd personally never want to make the sacrifices necessary to change the stock gearing. The stock gearing is the perfect compromise IMO.
That said, I'd personally NEVER change the final drive in the G37. A lot of guys here who don't understand gearing probably won't realize that there are penalties to pay for the greater leverage you get from more aggressive gearing. To me, it's just not worth it in a car like the G37. If you're talking about a track car, then fine...that might be worth it. But a street car? No thanks.
So what's wrong with changing the gearing? Well, not only will your fuel economy suffer (all else equal), but even more importantly, your car will forever be revving at a higher RPM. I like the fact that 6th gear is very much overdriven to the point that the car just hums along easily and quietly at highway speeds. My old 5.0L Mustang came with 2.73 gears and the car felt much more alive after I swapped in a set of 3.55 gears. But long highway trips sucked because the car was noisy due to the fact that the engine was now at a substantially higher RPM in every gear, including overdrive. It was fun zipping around town, but highway trips became something that I'd avoid. Another thing I like about the G37 is the long pulls between gear changes. Our engines aren't exactly high revving engines, but with the stock gearing the car pulls for a fairly long time between shifts. That's something that will change to some extent by swapping in more aggressive gears. I don't know, I just think of my G37 as more of a grand touring car than a stoplight racer. I'd personally never want to make the sacrifices necessary to change the stock gearing. The stock gearing is the perfect compromise IMO.
Yes, there will always be tradeoffs’ in gear selection. You are the first one I’ve ever heard mention that you like the long pulls between shifts. I can see that being desirable. But as you know, that’s a product of rear gears, transmission gearing, and power of the engine. If you like the setup, as you might for a touring car, then that’s great. But I on the other hand, want the car to accelerate. I don’t make long pulls between shifts very often, but I do have to stop at every stop sign and red light. That means I get a chance to accelerate again. I want the leverage to get going. We have other cars for touring, want we want the G37 for is to be a little pocket rocket. Yes, we could have bought a different car but we made some compromises. She wanted a G37 and I compromised. She wants the G to come out of the hole a little better and I’m pretty sure I could make that happen with a lower gear set. I just have the cruise control issue to get over first.
Wait a minute...your "proof" was a nice post with the math that says the G37 will go well over 155 after swapping gears. Now you're saying a real world figure is much less than your math suggests? Are you saying that you can't really figure it out with math?
I rest my case.
I rest my case.
I like to see that you know what you are talking about. I can remember back when I was 14 and we changed my dad’s 1987 Mustang GT gears from the stock 2.73’s over to 3.55’s. Later we added a Cartech turbo and should have changed the gears to 3.27’s but never got around to it. I also like that you know what you want in your car (you mentioned grand touring).
Yes, there will always be tradeoffs’ in gear selection. You are the first one I’ve ever heard mention that you like the long pulls between shifts. I can see that being desirable. But as you know, that’s a product of rear gears, transmission gearing, and power of the engine. If you like the setup, as you might for a touring car, then that’s great. But I on the other hand, want the car to accelerate. I don’t make long pulls between shifts very often, but I do have to stop at every stop sign and red light. That means I get a chance to accelerate again. I want the leverage to get going. We have other cars for touring, want we want the G37 for is to be a little pocket rocket. Yes, we could have bought a different car but we made some compromises. She wanted a G37 and I compromised. She wants the G to come out of the hole a little better and I’m pretty sure I could make that happen with a lower gear set. I just have the cruise control issue to get over first.
Yes, there will always be tradeoffs’ in gear selection. You are the first one I’ve ever heard mention that you like the long pulls between shifts. I can see that being desirable. But as you know, that’s a product of rear gears, transmission gearing, and power of the engine. If you like the setup, as you might for a touring car, then that’s great. But I on the other hand, want the car to accelerate. I don’t make long pulls between shifts very often, but I do have to stop at every stop sign and red light. That means I get a chance to accelerate again. I want the leverage to get going. We have other cars for touring, want we want the G37 for is to be a little pocket rocket. Yes, we could have bought a different car but we made some compromises. She wanted a G37 and I compromised. She wants the G to come out of the hole a little better and I’m pretty sure I could make that happen with a lower gear set. I just have the cruise control issue to get over first.
When I mention long pulls between shifts, you might remember how your dad's car was with the 2.73s in it. Talk about long pulls! I don't know why, but there's something I like about those long pulls, although I'd obviously rather not have them so long if I'm racing.
I also had an E36 M3 (5 speed) that seemed to have MUCH shorter pulls than the Mustang and that's one thing I really missed.
And now that I think about it, a big benefit of more aggressive gearing in the G37 is that you'll have far stronger acceleration in 6th gear at highway speeds. Decent top gear acceleration is something that I like in a sporty car. The G37 is pretty decent already, but with better gearing there's really no need at all to downshift at 60 MPH to pass on the highway. My M3 had AMAZING top gear acceleration, much better than any car I've ever owned. I loved the fact that I could be cruising on the highway in the top gear and I could accelerate really quickly without downshifting first.
Risk level? Swapping your rear differential gears is strictly a mechanical thing. It's pretty straightforward, but you still have to make sure that whoever does the swap knows how to properly set the backlash. Once it's done properly, there's virtually zero risk. I'm not sure what kind of risk you're talking about, but if you're worried that the rear diff will fail, that shouldn't be a concern at all.
Risk level? Swapping your rear differential gears is strictly a mechanical thing. It's pretty straightforward, but you still have to make sure that whoever does the swap knows how to properly set the backlash. Once it's done properly, there's virtually zero risk. I'm not sure what kind of risk you're talking about, but if you're worried that the rear diff will fail, that shouldn't be a concern at all.
Thanks!
I was going to do this mod but it wouldn't have helped since I might go FI. definitely a good money spent if you are stayin N/A...
a lot of the 2003-2004 G/Z guys are still having no issues w/ the rear end pumpkin swaps
a lot of the 2003-2004 G/Z guys are still having no issues w/ the rear end pumpkin swaps
Wait a minute...your "proof" was a nice post with the math that says the G37 will go well over 155 after swapping gears. Now you're saying a real world figure is much less than your math suggests? Are you saying that you can't really figure it out with math?
I rest my case.
I rest my case.
1. I proved beyond a reasonable doubt that the G can surpass 155mph.
2. the calculations neither factor in gear, nor are affected by it. Notice now there is no variable for gears. I simply stated that a 7AT with 4.08 FD happens to be geared nearly perfectly for the theoretical top speed
3. Since you're so into real world figures, let's use the Veyron as an example. Conventional mathematics (derived from analysis and published results) actually states the top speed of the Veyron is lower than what it actually does, and actual testing shows it does have the potential to go even faster than it already has.
4. You question me, instead of my evidence. Are you that insecure?
5. Lets not forget that you recommend Ester oil, when all hard evidence shows otherwise.
6. You provide anecdotal evidence for all of your statements, whereas I consistently provide mathematical evidence and/or test results, all of which you consistently ignore.
You have no case. The math is not perfect because the figures I am using are not perfect. The exact figures I need are not published, and the figures I use are subject to rounding error. If you have an advanced degree in mathematics, physics, engineering, or a similar field, I'd be more than happy to get into a more in-depth analysis. Until then, I will use layman figures and layman math, which results in a layman figure.
I'm sorry that you fail to understand that rounding error bring the figure up to 190 mph. Would you like a complete breakdown of how that 190 was reached? I can make this as complex as you'd like.
I've given you hard evidence. How about you give me some in the form of:
1. Mathematical analysis. (Formulas or CFD analysis or anything similar will suffice)
2. Video evidence of a G unable to go over 155 due to lack of output (not because of a governer or ultra short gears)
3. Credible sources that proves beyond a reasonable doubt that the G cannot go over 155.
Your anecdotal evidence consisting of "i've done this before", "I've heard this from so and so", and "seat of the pants" analysis simply isn't enough. My analysis is based on proven physics, data analysis, and on-track experience.
This looks to be a great mod for the G37. I plan to stay N/A, and instead of spending $1000+ on exhaust that will not provide any significant gains, I'm going to go with this instead.
Not sure about anyone else, but I could care less about being able to reach 155 MPH.
Not sure about anyone else, but I could care less about being able to reach 155 MPH.
This looks to be a great mod for the G37. I plan to stay N/A, and instead of spending $1000+ on exhaust that will not provide any significant gains, I'm going to go with this instead.
Not sure about anyone else, but I could care less about being able to reach 155 MPH.
Not sure about anyone else, but I could care less about being able to reach 155 MPH.
^+1 about reaching 155 lol.. I was reading NBS's other thread about the 4.08 and a lot of people were saying the install would take days... NBS can you chime in on how the install went and how long it exactly took?
I love your ability to interpret posts to suit your needs.
1. I proved beyond a reasonable doubt that the G can surpass 155mph.
2. the calculations neither factor in gear, nor are affected by it. Notice now there is no variable for gears. I simply stated that a 7AT with 4.08 FD happens to be geared nearly perfectly for the theoretical top speed
3. Since you're so into real world figures, let's use the Veyron as an example. Conventional mathematics (derived from analysis and published results) actually states the top speed of the Veyron is lower than what it actually does, and actual testing shows it does have the potential to go even faster than it already has.
4. You question me, instead of my evidence. Are you that insecure?
5. Lets not forget that you recommend Ester oil, when all hard evidence shows otherwise.
6. You provide anecdotal evidence for all of your statements, whereas I consistently provide mathematical evidence and/or test results, all of which you consistently ignore.
You have no case. The math is not perfect because the figures I am using are not perfect. The exact figures I need are not published, and the figures I use are subject to rounding error. If you have an advanced degree in mathematics, physics, engineering, or a similar field, I'd be more than happy to get into a more in-depth analysis. Until then, I will use layman figures and layman math, which results in a layman figure.
I'm sorry that you fail to understand that rounding error bring the figure up to 190 mph. Would you like a complete breakdown of how that 190 was reached? I can make this as complex as you'd like.
I've given you hard evidence. How about you give me some in the form of:
1. Mathematical analysis. (Formulas or CFD analysis or anything similar will suffice)
2. Video evidence of a G unable to go over 155 due to lack of output (not because of a governer or ultra short gears)
3. Credible sources that proves beyond a reasonable doubt that the G cannot go over 155.
Your anecdotal evidence consisting of "i've done this before", "I've heard this from so and so", and "seat of the pants" analysis simply isn't enough. My analysis is based on proven physics, data analysis, and on-track experience.
1. I proved beyond a reasonable doubt that the G can surpass 155mph.
2. the calculations neither factor in gear, nor are affected by it. Notice now there is no variable for gears. I simply stated that a 7AT with 4.08 FD happens to be geared nearly perfectly for the theoretical top speed
3. Since you're so into real world figures, let's use the Veyron as an example. Conventional mathematics (derived from analysis and published results) actually states the top speed of the Veyron is lower than what it actually does, and actual testing shows it does have the potential to go even faster than it already has.
4. You question me, instead of my evidence. Are you that insecure?
5. Lets not forget that you recommend Ester oil, when all hard evidence shows otherwise.
6. You provide anecdotal evidence for all of your statements, whereas I consistently provide mathematical evidence and/or test results, all of which you consistently ignore.
You have no case. The math is not perfect because the figures I am using are not perfect. The exact figures I need are not published, and the figures I use are subject to rounding error. If you have an advanced degree in mathematics, physics, engineering, or a similar field, I'd be more than happy to get into a more in-depth analysis. Until then, I will use layman figures and layman math, which results in a layman figure.
I'm sorry that you fail to understand that rounding error bring the figure up to 190 mph. Would you like a complete breakdown of how that 190 was reached? I can make this as complex as you'd like.
I've given you hard evidence. How about you give me some in the form of:
1. Mathematical analysis. (Formulas or CFD analysis or anything similar will suffice)
2. Video evidence of a G unable to go over 155 due to lack of output (not because of a governer or ultra short gears)
3. Credible sources that proves beyond a reasonable doubt that the G cannot go over 155.
Your anecdotal evidence consisting of "i've done this before", "I've heard this from so and so", and "seat of the pants" analysis simply isn't enough. My analysis is based on proven physics, data analysis, and on-track experience.
As far as you bringing up ester oil in this thread, well, that just proves that you have to resort to another argument to support your shortcomings in this one. Lets just stick to one subject at a time. It is obviously YOU who is insecure and you just proved it by "attacking" me. Sorry, but I do rest my case. I told you that you couldn't prove it with math and now even you admit that's the truth. Nice try, but real world application would prove you wrong and I'm quite sure that you know that, whether or not you want to admit it.
I've given you hard evidence. How about you give me some in the form of:
1. Mathematical analysis. (Formulas or CFD analysis or anything similar will suffice)
2. Video evidence of a G unable to go over 155 due to lack of output (not because of a governer or ultra short gears)
3. Credible sources that proves beyond a reasonable doubt that the G cannot go over 155.
