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never heard of the 4.4........but I have asked a lot of questions about changing the final drive ration when going turbo. Would this lengthen the gears or shorten them? When going turbo on an -e-shift, would it result in a faster car if you were able to lengthen the gears?


I heard 2nd gear is almost a waste.....just an extra shift for nothing.....
 

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2nd gear really doesnt exist. Its just an overdrive of first gear.
to solve that problem we have to wait for someone to come out with a tranny ecu to 'skip' over 2nd gear.
 

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I think it's either 3.27 or 3.909. I could be way off, though. You can find it on the net if you search.........
 

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xencloud said:
I think it's either 3.27 or 3.909. I could be way off, though. You can find it on the net if you search.........
One would have to know that number to compare to the 4.4 mentioned in the start of this thread.

My Firebird is 3.23 and I think the performance axle is 3.50.

The old Chevy's that were 1/4 mile fast were 4.11 and then 4.56. I believe.
 

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I just looked it up. For an e-shift IS300, the final drive is in fact 3.909:1.


info pending for the manual........


manual ifo found, it says 3.9:1 for the 5 speed with the lsd.

So how would the 4.4 affect gearing? Shorter, longer?
 

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So does it lengthen or shorten the gearing?
 

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It will give you lower overall gearing.

The engine will wind up faster in each gear.

The top speed may be lower.

Acceleration will be faster.

The car will have more torque off the line.

The RPM at a give speed will be higher.
 

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I think I just read an FAQ and answered myself. So the 4.4 would lengthen the gearing. So does anyone know if this would greatly benefit an e-shift that is turbo'd? Would it be beneficial for a stage 1 turbo car(275-300rwhp) , or only for cars pushing 350+rwhp?



<edit>I guess I read that FAQ backwards, please ignore this post! :crazy:
 

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It would all depend on what you are doing with the car.

If you run 1/8 mile, 1/4 mile, round track, big track with long straights, etc.

On thing for sure, your car would be really quick in the first 4 gears.
 

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Well, that was not what I was looking for. Maybe better for someone running NA. I was looking for a lower final drive. Does anyone know of a lower final drive?




p.s.-any turbo'd guys wanna give me some input as to how the e-shift does under boost? Would the car benefit with longer gears? Wouldn't you get better MPG, too?
 

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The stock redline and gearing is not good for that final drive. With a 4.4 you would be at around 4 or 4500 RPM in 5th gear doing 80MPH, which is not very practicle. The best gearing for our car in N/A form would be the 6 speed Supra tranny with the stock 3.9 automatic final drive. The acceleration with that set up would be slightly faster then the 98 body M3 and the 350z, gearing wise.
 

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xencloud said:
Well, that was not what I was looking for. Maybe better for someone running NA. I was looking for a lower final drive. Does anyone know of a lower final drive?




p.s.-any turbo'd guys wanna give me some input as to how the e-shift does under boost? Would the car benefit with longer gears? Wouldn't you get better MPG, too?
Yes a higher final drive will not be very good for boost, becuse you want to stay in each gear as long as you can so that the boost will accelerate it, if you shitft every 2 seconds, the boost wont do it's job.

The turbo supra has a 3.2 or so final drive, which will make the stock gearing slightly longer.
 

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Verdict: Someone needs to come out with a lower final drive gear!
 

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xencloud said:
Well, that was not what I was looking for. Maybe better for someone running NA. I was looking for a lower final drive. Does anyone know of a lower final drive?
I'm sure this is possible, you just need to find something that bolts on to our cars or can be easily fitted unless you want to do lots of fab work to make it fit. The supras rears have been done by lots of shops with the getrag, so I would assume it would fit with the auto and manual trannies we have with only minor fabrication

xencloud said:
p.s.-any turbo'd guys wanna give me some input as to how the e-shift does under boost? Would the car benefit with longer gears? Wouldn't you get better MPG, too?
The e-shift works fine under boost, but I have to say that the car is better at shifting gears then I will ever be. I was a diehard manual kinda guy until I bought the IS and there were no manual trannies. Now I'm glad I have the auto. The car changes gears so quick and smoothly that it typically seems like 1st-4th are just one long gear. The car never loses boost and never stops accelerating.

Somebody knock me down if I'm wrong here, but the drive ratio is the ratio of the number of revolutions of the driveshaft to complete one revolution of the drive wheels. So, a longer(read smaller number) set of gears, like 3.73:1 or 3.2:1, would require fewer turns of the driveshaft than say a set of shorter (read higher number), like 3.909:1 or 4.11:1.

If you're looking for better response from less power, then shorter gears are the way to go. If you want higher top end, longer gears are the way to go. For the purposes of mileage, I would really like to see a longer final ratio for cruising. Unfortunately, you cannot change the rear end to only affect one of the gears in the transmission. They all connect to the rear end of the car through the same driveshaft and the rear end in our cars is not variable (I'm pretty sure that's the way it is in all cars). If a variable rear-end was available, I'm sure everyone would have it as you could optimize it, on the fly so to speak, for whatever application you needed it for, i.e. for trips or mileage intensive adventures, you could set it as close to 1:1 as possible, increasing your economy, and for racing you could set it much higher, like 4:1 or maybe more depending on the maximum rpm achievable by your engine. Something that redlines at 12k could probably take 6:1 or more(maybe?). I guess this doesn't really apply to bikes, but the final drive ratio on my cbr 954 is nearly 1:1.

As far as our second gear being a wasted shift, I'm not sure I understand why you say that. Second gear feels like a second gear to me, with the car continually accelerating from first through fourth with no delay along the way. There doesn't seem to be anything "lost" in second, especially not in the amount of time it takes the car to shift from first to second, or second to third. Even though the time spent in 2nd at WOT isn't as long as say 3rd or 4th gear, it's not supposed to be. I believe that without second, especially when my car was n/a, the rpm drop would put the car out of the ideal powerband. In the manual tranny car, assuming the gear ratios are the same(I haven't verified this), I could see the argument against second as the amount of time to shift into and out of second is probably about the same amount of time you would spend in second.

Changing only the final gear ratio would require a truly new gear inside the transmission. This may be an impossibility due the the tight quarters inside the transmission casing. I don't know if that's possible or not or how much of a difference can be had by changing this. If we had five "real" gears in our transmissions, then I would love to see a longer 5th gear, but since we don't and overdrive is merely and extension of "fourth", if you will, I don't know what the plausability of this is.
 

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Thanks for the input Darkstorm! I appreciate the informative post.


anyone else? This could be a bad idea, I'm just pursuing the question just in case. Do you think your experience would apply to other kits besides PFS kits? I know PFS has the auto thing done right.
 
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