Questions regarding a mod I'd like to do (4.08:1)
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Questions regarding a mod I'd like to do (4.08:1)
I've been thinking over the past few months since I purchased my Z, that I'd like to do a cost effective mod to add a few or 35 hp. The most cost effective mod I've seen so far would be a final drive upgrade. Specifically, I'm thinking about replacing the stock 3.5:1 with a 4.08:1 which would be purchased here.
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
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I have the 3.9, as thats what was popular at the time but the 4.081 seems to be the new popular fd. I don't know where your located but take it to a shop you can trust and everything should be fine. It's quite an improvement. If you have a base model it would be a good idea to get an lsd at the same time as they have to be installed together. Labor costs will vary look around here for shops in your area and get an estimate. Also just an fyi the final driver ring and pinion goes in the differential not the transmission.
My fuel economy around town didn't go down very much as you can go a gear higher in most cases but highway mileage will go down of course.
My fuel economy around town didn't go down very much as you can go a gear higher in most cases but highway mileage will go down of course.
Last edited by cavallino33; 04-21-2008 at 10:12 AM.
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Originally Posted by Modulus
I've been thinking over the past few months since I purchased my Z, that I'd like to do a cost effective mod to add a few or 35 hp. The most cost effective mod I've seen so far would be a final drive upgrade. Specifically, I'm thinking about replacing the stock 3.5:1 with a 4.08:1 which would be purchased here.
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
By the way when I was talking to Rich he said the fuel economy didnt change by more than roughly 2 mpg. In my opinion, well worth the improvement.
Last edited by ZenDragon; 04-21-2008 at 10:18 AM.
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Originally Posted by cavallino33
Also just an fyi the final driver ring and pinion goes in the differential not the transmission.
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There's a great sticky at the top of this forum dedicated to this mod... Mod can delete this thread if you want. Sorry for not checking first.
p.s. thanks for the encouragement every1
p.s. thanks for the encouragement every1
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Originally Posted by Modulus
I've been thinking over the past few months since I purchased my Z, that I'd like to do a cost effective mod to add a few or 35 hp. The most cost effective mod I've seen so far would be a final drive upgrade. Specifically, I'm thinking about replacing the stock 3.5:1 with a 4.08:1 which would be purchased here.
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
Anyone experienced with this kind of mod that can shed some light on the subject? How easily could a mechanic who doesn't know what he's doing F up my ride attempting a mod like this? How much could I expect to spend on labor? Is the transmission easily accessible in the Z? Or would the mechanic have to tear the thing apart to get to it...
15% more acceleration for $500 is unbeatable. Of course, my FE is going to go to ****, but that's the trade off I guess. I'm ok with that.
Thanks,
Mod
LOLOLOL
I love how those guys couldn't even take the time to write their OWN product description, they had to steal mine (used my picture too, but that is far less offensive)
http://www.z1auto.com/prodmore.asp?m...ne&prodid=2833
Last edited by Z1 Performance; 04-22-2008 at 05:19 AM.
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Originally Posted by Z1 Performance
LOLOLOL
I love how those guys couldn't even take the time to write their OWN product description, they had to steal mine (used my picture too, but that is far less offensive)
http://www.z1auto.com/prodmore.asp?m...ne&prodid=2833
I love how those guys couldn't even take the time to write their OWN product description, they had to steal mine (used my picture too, but that is far less offensive)
http://www.z1auto.com/prodmore.asp?m...ne&prodid=2833
And what the hell is toy box auto?
#13
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Originally Posted by Modulus
I've been thinking over the past few months since I purchased my Z, that I'd like to do a cost effective mod to add a few or 35 hp.
Mod
Mod
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Just because you increase gearing by 15% doesn't mean you increase acceleration by 15%..............it is more like the cube root [little less than cube more like 2.5 root] of the 15% more like 2.5% time wise.
A 15% increase in rear wheel torque via gear multiplication can however decrease quarter mile by 0.2-0.3 seconds if you don't loose time by shifting to another gear [shift time loss vs acceleration gained].
We've had a few Q45 [stock 3.538 diff] do these 4.083 conversions. The major change has been the 10-12% decline in highway MPG.
Also you won't see a measured 15% increase in wheel torque because the higher ratio increases the frictional losses in differential by about 0.5-1%
A 15% increase in rear wheel torque via gear multiplication can however decrease quarter mile by 0.2-0.3 seconds if you don't loose time by shifting to another gear [shift time loss vs acceleration gained].
We've had a few Q45 [stock 3.538 diff] do these 4.083 conversions. The major change has been the 10-12% decline in highway MPG.
Also you won't see a measured 15% increase in wheel torque because the higher ratio increases the frictional losses in differential by about 0.5-1%
Last edited by Q45tech; 04-30-2008 at 09:08 AM.
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you're splitting hairs in a major way
Perhaps that larger decline in gas mileage has to do with it being a far heavier car, with an auto transmission, and an already thirst v8
On the Z, the change in mileage is negliable at best. I've had the 3.9 on my car for years now...more years with it, than without it in fact, and my mileage has stayed exactly the same as when the car had the std. rear in it. I am sure those with a 4.08 can comment on their mileage changes directly.
Perhaps that larger decline in gas mileage has to do with it being a far heavier car, with an auto transmission, and an already thirst v8
On the Z, the change in mileage is negliable at best. I've had the 3.9 on my car for years now...more years with it, than without it in fact, and my mileage has stayed exactly the same as when the car had the std. rear in it. I am sure those with a 4.08 can comment on their mileage changes directly.
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Originally Posted by Z1 Performance
you're splitting hairs in a major way
Perhaps that larger decline in gas mileage has to do with it being a far heavier car, with an auto transmission, and an already thirst v8
On the Z, the change in mileage is negliable at best. I've had the 3.9 on my car for years now...more years with it, than without it in fact, and my mileage has stayed exactly the same as when the car had the std. rear in it. I am sure those with a 4.08 can comment on their mileage changes directly.
Perhaps that larger decline in gas mileage has to do with it being a far heavier car, with an auto transmission, and an already thirst v8
On the Z, the change in mileage is negliable at best. I've had the 3.9 on my car for years now...more years with it, than without it in fact, and my mileage has stayed exactly the same as when the car had the std. rear in it. I am sure those with a 4.08 can comment on their mileage changes directly.
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I went from 3.3 to 3.7 in an AT G... mpg did suffer, but not enough for me to care... most people that do a performance mod are willing to sacrifice mpg anyway (otherwise, keep it stock - you won’t get better mpg than that).