captainhook Posted March 11, 2009 Share Posted March 11, 2009 Another thread got me curious as to what speed the 5EAT cars are limited to in 4th and 5th gear. I know it's freakin high, but how high? (all assuming the speed limiter is removed and it's rolling on stock rims + tires) Anyone have a clue? Link to comment Share on other sites More sharing options...
j255c Posted March 11, 2009 Share Posted March 11, 2009 someone made a chart a while back, showing the 5mt 4.11 final gear 5mt 3.9 and the spec b. Ill try to dig it up. 06 TB EVO IX SE stock turbo monster subaru hater Link to comment Share on other sites More sharing options...
captainhook Posted March 11, 2009 Author Share Posted March 11, 2009 I don't know if this will help, but I did dig the 5EAT ratios up from an ancient thread: 1st: 3.540 2nd: 2.264 3rd: 1.471 4th: 1.000 5th: 0.834 Link to comment Share on other sites More sharing options...
FocuS Posted March 11, 2009 Share Posted March 11, 2009 I buried the speedo in 5th on the Leg before fuel cut around 7k RPM...More info in PM if desired... Link to comment Share on other sites More sharing options...
sactojesse Posted March 11, 2009 Share Posted March 11, 2009 Do the math. mph = (rpm x tire diameter in inches)/(gear ratio x 336) Fourth gear ratio in a 5EAT = 1 x 3.272 final drive = 3.272 Fifth gear ratio in a 5EAT = 0.834 x 3.272 final drive = 2.729 Tire diameter of a 215/45R17 = 24.6 inches Redline = 6,500 rpm Ergo, theoretical top speeds in fourth and fifth gears, assuming that the car can overcome aerodynamic drag to reach redline, are: mph in fourth = (6,500 x 24.6)/(3.272 x 336) = 145.5 mph mph in fifth = (6,500 x 24.6)/(2.729 x 336) =174.4 mph Obviously, your car won't be able to pull 6,500 in fifth, but that's what the theoretical speeds at redline would be. Link to comment Share on other sites More sharing options...
frkkevin Posted March 11, 2009 Share Posted March 11, 2009 If I remember 161 @ 7000k rpm in 5th depending on tire size.. 4th will at least carry you to +/-140 512whp/465ftlb 2005 5EAT Legacy (Build Log) Videos - - Link to comment Share on other sites More sharing options...
sactojesse Posted March 11, 2009 Share Posted March 11, 2009 For comparison, here's the math for a 5MT (not 5EAT) LGT w/ stock 17-inch rims/tires: mph = (rpm x tire diameter in inches)/(gear ratio x 336) Fourth gear ratio in a 5MT = 0.972 x 4.111 final drive = 3.996 Fifth gear ratio in a 5MT = 0.738 x 4.111 final drive = 3.034 Tire diameter of a 215/45R17 = 24.6 inches Redline = 6,500 rpm Theoretical top speeds in fourth and fifth gears at redline: mph in fourth = (6,500 x 24.6)/(3.996 x 336) = 119.1 mph mph in fifth = (6,500 x 24.6)/(3.034 x 336) = 156.9 mph As you can see, the 5MT is geared considerably lower than the 5EAT. Link to comment Share on other sites More sharing options...
captainhook Posted March 12, 2009 Author Share Posted March 12, 2009 Do the math. mph = (rpm x tire diameter in inches)/(gear ratio x 336) Fourth gear ratio in a 5EAT = 1 x 3.272 final drive = 3.272 Fifth gear ratio in a 5EAT = 0.834 x 3.272 final drive = 2.729 Tire diameter of a 215/45R17 = 24.6 inches Redline = 6,500 rpm Ergo, theoretical top speeds in fourth and fifth gears, assuming that the car can overcome aerodynamic drag to reach redline, are: mph in fourth = (6,500 x 24.6)/(3.272 x 336) = 145.5 mph mph in fifth = (6,500 x 24.6)/(2.729 x 336) =174.4 mph Obviously, your car won't be able to pull 6,500 in fifth, but that's what the theoretical speeds at redline would be. Ahh, that's exactly what I was looking for! Nice math layout, thanks. Link to comment Share on other sites More sharing options...
ShadowImg Posted March 12, 2009 Share Posted March 12, 2009 Tire circumference, not tire diameter, right? Also the 08 5eat as far as I know has a 3.08 final drive. Link to comment Share on other sites More sharing options...
sactojesse Posted March 12, 2009 Share Posted March 12, 2009 Tire circumference, not tire diameter, right? Also the 08 5eat as far as I know has a 3.08 final drive. Tire diameter, not circumference. Tire diameter is the diameter of the wheel plus 2x the sidewall height, which can be calculated from the aspect ratio and tire width. True, the 2.5GT 5EAT went to 3.083 ring and pinion ratio in 08. I used the 3.272 R&P ratio for 05-07 since the OP did not specify. Link to comment Share on other sites More sharing options...
ShadowImg Posted March 12, 2009 Share Posted March 12, 2009 Why does diameter determine anything? Or is that where the 336 constant comes from? It seems like circumference * rpm / ratio determines the distance travelled over time rather than diameter. 4th Ratio (1.00) x Final Drive (3.083) = 3.083 Tire diameter of 24.7in x pi (3.14) = 77.558in per rotation of a tire 6500rpm / 3.083 gear ratio = 2108.33 tire rotations per minute 77.558in * 2108.33 = 163518.32 inches per minute 163518.32in * 60 = 9811099.57 inches per hour 9811099.57 / 63360 inches per mile = 154.84 mph Your method is much more simple, but I'm terrible at math so I'm not sure how you're simplifying this and/or making diameter relevant for anything other than calculating circumference Link to comment Share on other sites More sharing options...
sactojesse Posted March 12, 2009 Share Posted March 12, 2009 Why does diameter determine anything? Or is that where the 336 constant comes from? It seems like circumference * rpm / ratio determines the distance travelled over time rather than diameter. 4th Ratio (1.00) x Final Drive (3.083) = 3.083 Tire diameter of 24.7in x pi (3.14) = 77.558in per rotation of a tire 6500rpm / 3.083 gear ratio = 2108.33 tire rotations per minute 77.558in * 2108.33 = 163518.32 inches per minute 163518.32in * 60 = 9811099.57 inches per hour 9811099.57 / 63360 inches per mile = 154.84 mph Your method is much more simple, but I'm terrible at math so I'm not sure how you're simplifying this and/or making diameter relevant for anything other than calculating circumference The 336 constant apparently factors in all of those conversions. I do, however, like the fact that you just "mathed" all that out without it. There's someone else besides me who likes to crunch numbers. Link to comment Share on other sites More sharing options...
Sdrvr Posted March 13, 2009 Share Posted March 13, 2009 Just happened to do a little trip after reading this. 4th 3250 @ 75 mph. 2x = 150 mph 5th 2150 @ 60 mph. 3x = 180 mph Now how about somebody calculate how much whp to reach those speeds? Link to comment Share on other sites More sharing options...
captainhook Posted March 13, 2009 Author Share Posted March 13, 2009 Tire diameter, not circumference. Tire diameter is the diameter of the wheel plus 2x the sidewall height, which can be calculated from the aspect ratio and tire width. True, the 2.5GT 5EAT went to 3.083 ring and pinion ratio in 08. I used the 3.272 R&P ratio for 05-07 since the OP did not specify. Interesting, I didn't realize it changed from 07 to 08. The difference between 174 and 154 is obviously pretty substantial. I wonder why they changed the ratios. Link to comment Share on other sites More sharing options...
sactojesse Posted March 13, 2009 Share Posted March 13, 2009 Interesting, I didn't realize it changed from 07 to 08. The difference between 174 and 154 is obviously pretty substantial. I wonder why they changed the ratios. No, the 154 mph figure that was ShadowImg's calculated theoretical max speed with the 08/09 LGT's 3.083 ring and pinion in fourth gear. The 3.083 ring and pinion in the 08/09 5EAT LGT's is taller, i.e., numerically lower, than the 3.272 ring and pinion in the 05-07 5EAT LGT's and would thus yield a higher theoretical top speed at redline. Fifth gear numbers would be as follows: mph = (rpm x tire diameter in inches)/(gear ratio x 336) Fifth gear ratio in a 5EAT = 0.834 x 3.083 final drive = 2.571 Tire diameter of a 215/45R17 = 24.6 inches Redline = 6,500 rpm mph in fifth = (6,500 x 24.6)/(2.571 x 336) =185.1 mph As mentioned previously, your car won't be able to pull 6,500 in fifth, but that's what the theoretical speed at redline would be if it could. Link to comment Share on other sites More sharing options...
captainhook Posted March 14, 2009 Author Share Posted March 14, 2009 Haha, that's ridiculous. Thanks for the input guys. Link to comment Share on other sites More sharing options...
Richard B. Posted March 15, 2009 Share Posted March 15, 2009 Obviously, your car won't be able to pull 6,500 in fifth, but that's what the theoretical speeds at redline would be. why not? the gt is pretty aerodynamic. more so than some famous sport cars. if a gti can hit close to 190 why cant the gt hit 170+? saw a vid of a midly modded b5s4 doing 186 down the autobahn. please tell me why the legacy wouldn't hit 170+... Link to comment Share on other sites More sharing options...
vduber Posted March 15, 2009 Share Posted March 15, 2009 I agree with you that our gt should hit 170 but it would have to be running a signifcantly large turbo and I would think it would have to be making close to 500 awhp. Frkkevin hit 161 in his gt and he's running a fp red through his 5eat making a little over 400 so i dont think it's impossible but at those speeds you do need mucho power to overcome drag. O yea and I think that b5 s4 was probably running twin k04's or gt25r's which can produce 500 whp. Anyway nice math guys, I wouldn't attempt it cause I just hate math Link to comment Share on other sites More sharing options...
vduber Posted March 15, 2009 Share Posted March 15, 2009 Woops I just realized that frkkevin wasn't driving at those speeds but thats what he thought top speed in 5th was, sorry but I still believe we could produce enough powsa to hit 170 Link to comment Share on other sites More sharing options...
Richard B. Posted March 15, 2009 Share Posted March 15, 2009 I agree with you that our gt should hit 170 but it would have to be running a signifcantly large turbo and I would think it would have to be making close to 500 awhp. Frkkevin hit 161 in his gt and he's running a fp red through his 5eat making a little over 400 so i dont think it's impossible but at those speeds you do need mucho power to overcome drag. O yea and I think that b5 s4 was probably running twin k04's or gt25r's which can produce 500 whp. Anyway nice math guys, I wouldn't attempt it cause I just hate math no they do NOT have twin ko4 with 500awhp. do you have ANY proof or just s**t and heresay? the gti on the you tube hitting 190 def does NOT have 500whp. as i said...the gt is pretty aerodynamic. look it up and compare. once i cracked 120 just for the hell of it and the car was still pulling. that's on stage 1. i'd bet 150 on stage 1 isn't difficult with enough road. Link to comment Share on other sites More sharing options...
frkkevin Posted March 15, 2009 Share Posted March 15, 2009 Woops I just realized that frkkevin wasn't driving at those speeds but thats what he thought top speed in 5th was, sorry but I still believe we could produce enough powsa to hit 170 Fastest I've taken it was 155 with a little legroom .. and if I can remember that was Stage II? The car will pull top end just not near as fast as if you had more power 512whp/465ftlb 2005 5EAT Legacy (Build Log) Videos - - Link to comment Share on other sites More sharing options...
vduber Posted March 16, 2009 Share Posted March 16, 2009 no they do NOT have twin ko4 with 500awhp. do you have ANY proof or just s**t and heresay? the gti on the you tube hitting 190 def does NOT have 500whp. as i said...the gt is pretty aerodynamic. look it up and compare. once i cracked 120 just for the hell of it and the car was still pulling. that's on stage 1. i'd bet 150 on stage 1 isn't difficult with enough road. Ok well first of all you dont need 500 whp( I over did it there) to get there but there are very few places in the world where you have miles and miles of road w/o other vehicles while accelerating at a ridiculously slow rate of speed to get to 170 mph. And in the first place I was agreeing with you so I don't understand why your coming at me like im the f***** devil. Also if this is the video your looking at [ame=http://www.youtube.com/watch?v=uUDUvDSaBN4]YouTube - Broadcast Yourself.[/ame], he says in his other videos that he is modded. So how the f*** do you know if he does or doesn't have twin k04's do you have any proof or just S*** and heresay? If you want to know so bad try doing it yourself! But if you really want to go 170 mph just throw it on a dyno to make yourself feel better. Link to comment Share on other sites More sharing options...
vduber Posted March 16, 2009 Share Posted March 16, 2009 And why do you say the gt is "pretty" aerodynamic have you personally run it through a wind tunnel? Just because it looks aerodynamic doesn't mean it is! You come barking at me with asking for facts i'll do the same to you. Link to comment Share on other sites More sharing options...
LuckyBob Posted March 18, 2009 Share Posted March 18, 2009 And why do you say the gt is "pretty" aerodynamic have you personally run it through a wind tunnel? Just because it looks aerodynamic doesn't mean it is! You come barking at me with asking for facts i'll do the same to you. Ok. Done deal. Granted they're not authoritve soruces but it's still a well known statistic. 2007 Legacy drag coefficient: 0.29 2007 STI drag coefficient: 0.33 For comparison - 2007 Ferarri F430 drag coefficient: 0.33 Link to comment Share on other sites More sharing options...
bradlgt21 Posted March 18, 2009 Share Posted March 18, 2009 Are thse numbers legit? I believe that the LGT would be better then the STI but better then the Ferarri is hard to believe that thing looks sleek. Link to comment Share on other sites More sharing options...
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