collegemt Posted April 12, 2008 Share Posted April 12, 2008 I was searching cars101.com and noticed that the 05-07 have different final reduction vs the 08. I am not sure what this means. If someone could explain it to me that would be great. Which one has better acceleration capabilities? 05-07 gearing specs from cars101.com: 5spd manual available on GT sedan only 1st 3.166 2nd 1.882 3rd 1.296 4th .972 5th .738 final reduction 4.111 08 gearing specs froom cars101.com: 5spd manual available on GT sedan only 1st 3.166 2nd 1.882 3rd 1.296 4th 0.972 5th .738 final reduction 3.900 Link to comment Share on other sites More sharing options...
BigBad Posted April 12, 2008 Share Posted April 12, 2008 Not sure that there would be a huge difference but the 4.11 gearing should give you better off the line acceleration. I think the gearing change was done to improve gas mileage more than anything else. Link to comment Share on other sites More sharing options...
franklin Posted April 12, 2008 Share Posted April 12, 2008 The 4.11 would accelerate faster than 3.90 geared cars all things being equil. All the other ratios are the same. If I had my choice I would keep the '05 1st to 5th gearing and 4.11 rear gear and add a taller 6th gear for highway cruising. Say something like 0.65 This would retain all the goodness of 1-5 and the efficiency in 6th Link to comment Share on other sites More sharing options...
JoeFromPA Posted April 12, 2008 Share Posted April 12, 2008 Agreed with franklin. The 08 final reduction gives you a little more "in gear" pulling time, which is nice in it's way. I don't feel this engine revs high at all on the highway, though I am currently driving a car that revs high all the time A 6th gear would've been a much better choice. Joe Link to comment Share on other sites More sharing options...
lilbrudder Posted April 12, 2008 Share Posted April 12, 2008 what are the #'s for the spec-b? is it possible to put a smaller 5th in if doing a gear box rebuild(for lower highway cruising RPM's)? Link to comment Share on other sites More sharing options...
collegemt Posted April 12, 2008 Author Share Posted April 12, 2008 The Spec be has changed every year: 06 Specs: 5spd manual available on sedan only including spec.B 1st 3.166 2nd 1.882 3rd 1.296 4th .972 5th .738 final reduction 4.111 07 Specs: 6 spd manual, spec.B only 1st 3.636 2nd 2.235 3rd 1.521 4th 1.137 5th 0.891 6th 0.707 final 3.454 08 Specs: 6 spd manual, spec.B only 1st 3.636 2nd 2.235 3rd 1.521 4th 1.137 5th 0.891 6th 0.707 final 3.900 Link to comment Share on other sites More sharing options...
BlackHole Posted April 12, 2008 Share Posted April 12, 2008 ^^ Are those 07 specs right? That would be super-tall gearing. Kyle "BlackHole" Link to comment Share on other sites More sharing options...
collegemt Posted April 12, 2008 Author Share Posted April 12, 2008 ^^ Are those 07 specs right? That would be super-tall gearing. Cut and pasted from cars101.com Link to comment Share on other sites More sharing options...
camber Posted April 15, 2008 Share Posted April 15, 2008 '07 spec. B final drive ratio is 3.9 3.454 is a common first gear ratio on some subies. Maybe, the cars101 data entry person, got a little ahead of themselves and made a typo:lol: Link to comment Share on other sites More sharing options...
camber Posted April 15, 2008 Share Posted April 15, 2008 Maybe, they got confused with the rear diff ratio of 3.545 and forgot about the trasmission reduction of 1.1 on the 6MT? Link to comment Share on other sites More sharing options...
chenc544 Posted April 15, 2008 Share Posted April 15, 2008 '07 spec. B final drive ratio is 3.9 3.454 is a common first gear ratio on some subies. Maybe, the cars101 data entry person, got a little ahead of themselves and made a typo:lol: IIRC the problem wasn't cars101 but SOA. I remember seeing the same number on a bunch of other publications so SOA must have put out the wrong number. Anyway, this was discussed before and the RPM at speed of '07 owners have verified that the assumption. Link to comment Share on other sites More sharing options...
chenc544 Posted April 15, 2008 Share Posted April 15, 2008 The 4.11 would accelerate faster than 3.90 geared cars all things being equil. All the other ratios are the same. If I had my choice I would keep the '05 1st to 5th gearing and 4.11 rear gear and add a taller 6th gear for highway cruising. Say something like 0.65 This would retain all the goodness of 1-5 and the efficiency in 6th IMHO, that's what Subaru should had done with the Spec B's 6MT. The EJ25 really doesn't need a close ratio 6MT to get the most out of it, the 5MT's ratio was more than enough. A much taller 6th gear, aka Corvette's 2 overdrive gear box, would have given the Spec B a very desirable advantage over the 5MT LGT on highway fuel economy. Link to comment Share on other sites More sharing options...
rao Posted April 15, 2008 Share Posted April 15, 2008 But then it would have 1 less gear and that's bad for marketing Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
chenc544 Posted April 15, 2008 Share Posted April 15, 2008 But then it would have 1 less gear and that's bad for marketing Huh, why would it have 1 less gear? Link to comment Share on other sites More sharing options...
rao Posted April 15, 2008 Share Posted April 15, 2008 Whoops! Nevermind I can tell you that my T-56 car turns about 1500 rpm at 80 Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
chenc544 Posted April 15, 2008 Share Posted April 15, 2008 I can tell you that my T-56 car turns about 1500 rpm at 80 I know, that's just crazy. And people wonder why Corvette is rated at 26 mpg on the highway. Link to comment Share on other sites More sharing options...
lilbrudder Posted April 15, 2008 Share Posted April 15, 2008 is it possible to put a smaller 5th in if doing a gear box rebuild(for lower highway cruising RPM's)? anyone think it's doable? that sure would be nice going 80 @ 1500rpms. Link to comment Share on other sites More sharing options...
BlackHole Posted April 16, 2008 Share Posted April 16, 2008 I know, that's just crazy. And people wonder why Corvette is rated at 26 mpg on the highway. The crazy thing is that the the Corvette can pull that super-tall gear just fine. Big motors FTW. Even with a 2.5T acceleration at that rpm would be slow as molasses on a winter morning. Kyle "BlackHole" Link to comment Share on other sites More sharing options...
chenc544 Posted April 16, 2008 Share Posted April 16, 2008 anyone think it's doable? that sure would be nice going 80 @ 1500rpms. As long as a vendor is willing to make the gear it's certainly possible, but keep in mind it will be pretty expensive. There is a vendor that makes aftermarket final gear ratio for the Z and it's ~$700 for the gear itself. Add in the rebuild cost for the transmission and it will take a very long time to pay it off with gas savings. 1500 rpm is probably too low for the EJ25 at 80 mph, I will be very happy if it's less than 2500 rpm. Link to comment Share on other sites More sharing options...
JoeFromPA Posted April 16, 2008 Share Posted April 16, 2008 I think it's a bad idea....I don't think this motor can hold itself in a top gear at 80mph if it's doing 2000rpms. I notice that this car, due to it's lack of low-end and pretty poor aerodynamics, needs to have a decent amount of gas given to it to maintain speed on the highway. I think a super tall overdrive gear would not necessarily give you better fuel economy. The Corvette can also turn 1500 rpms because it's got the low-end power and it has very little aerodynamic drag. Joe Link to comment Share on other sites More sharing options...
MilesA Posted April 17, 2008 Share Posted April 17, 2008 ...I notice that this car, due to it's lack of low-end and pretty poor aerodynamics, needs to have a decent amount of gas given to it to maintain speed on the highway... Coefficient of drag for Sedan ~= .29 Coefficient of drag for Wagin ~= .31 Pretty good numbers, actually. To get an idea of total drag, you need to multiple the Coefficient by the frontal area of the car, which for our cars is slightly smaller compared to Camry, Accord, etc. So total aero drag is at least average, if not better than average. We do have the full-time AWD which is more resistance to overcome. Remember we have throttle-by-wire, the accelerator pedal is only one input into the system. I find my car takes a fairly light touch, but feedback from the pedal is only an illusion, anyway. Link to comment Share on other sites More sharing options...
JoeFromPA Posted April 17, 2008 Share Posted April 17, 2008 I don't know about the frontal area, but you are right on the drag coefficient. I thought it was much higher than that (i.e. .35) due in large part to the hood scoop. .29 is unbelievable for this car....my 06 Civic SI, with a much sleeker overall shape, lower to the ground, no hood scoop, and a windshield raked way-the-hell back puts about the same coefficient up Anyway, I stand by my point though. This car seems to require significant engine power at ~75mph to maintain speed, whether due from low-end or (what I thought) aerodynamics or both, so I don't think it'd be a good idea to make the overdrive gearing much taller. Joe Edit: Agree, to a point, on the pedal input. I don't think it's feedback from the pedal, I think it's visual and tactile feedback of the car slowing down unless additional pedal-pushing is a'given. Note also the MPG guage's swing to the left Link to comment Share on other sites More sharing options...
Underdog Posted April 17, 2008 Share Posted April 17, 2008 Joe, can you explain why it feels like there car requires significant engine power to cruise? Not why does it require the power, but what about the driving experience makes you feel that way? I have a theory but want it to be relevant to your experience. The Crimson Dynamo Link to comment Share on other sites More sharing options...
BlackHole Posted April 17, 2008 Share Posted April 17, 2008 IMO it's driveline losses. My ancient brick-on-wheels 160k mi AWD 1991 Galant VR4 got better mileage than my LGT and took longer to coast-down from speed. Now on my second Subie, I've been very disappointed with their drivetrains. Kyle "BlackHole" Link to comment Share on other sites More sharing options...
JoeFromPA Posted April 18, 2008 Share Posted April 18, 2008 Underdog, To be honest, it might just be getting used to the car. But cruising in this car at a single speed does not seem effortless. Could be the extra mechanical drag. I thought it was aerodynamics as well. Could be high-rolling resistance re92s. Could be that my other car has a bottom-hinged gas pedal and I'm getting used to the pedal coming from the top. Could be the swings of the MPG guage, which prompt my attention to changing throttle input. I just notice that this car seems to need more attention to maintain a set speed, absent cruise control. Joe Link to comment Share on other sites More sharing options...
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