Top speed with FI
08-04-2005, 10:21 PM
#28
All just fine, with no wind resistance. You could gear it to run 400 and if the dyno could handle it you'd get there. All because the dyno will release the drag until you get where you want to go. In the end your just spinning a couple of rollers with nothing to slow them down. This test means nothing, less then nothing.
How much load did it have? What was the HP being delivered.
It is possable on the better dynos to program in for all the real world drain.
Does anyone know the CD for the 8? That and the frontal area will tell you how much wheel HP it takes to go so fast. Lets see if I remember it.
CD x frontal area x MPH to the cube, over 146,600.
This is to maintain the speed, it takes a lot more to get there. How much will depend on how long the course is.
How much load did it have? What was the HP being delivered.
It is possable on the better dynos to program in for all the real world drain.
Does anyone know the CD for the 8? That and the frontal area will tell you how much wheel HP it takes to go so fast. Lets see if I remember it.
CD x frontal area x MPH to the cube, over 146,600.
This is to maintain the speed, it takes a lot more to get there. How much will depend on how long the course is.
08-05-2005, 06:37 AM
#31
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the answer should be yes. in my experience, most rwd cars have a sensor mounted on the transmission just before the driveshaft exits. this usually measures driveshaft rpm, then calculates vehicle speed by dividing the rpm by some number to determine vehicle speed. now this may not be the case with the 8, they may pull vehicle speed from the abs sensors as that would make more sense, they have 4 wheel speed sensors for the abs, so why add another sensor. dont know, ill have to take a look at the shop manual.
08-05-2005, 01:09 PM
#32
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I've actually hit 155mph on the way to vegas, on a safe long , flat, straight stretch. I was going to snap a picture of it with my camera but thought it was too dangerous to take my hands off the wheel. At that time I had nothing but a RB exhaust.
08-05-2005, 02:16 PM
#36
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I have checked all over my manual transmission and thereis NOT a speed sensor.The manual says the signal for the speedometer is taken from the ABS/TCM unit and the ABS sensors.The AUTOMATIC has a speed ensor in the transmission.
Speed ometer calibration will be affected by the rolling circumference of the wheel/tire combination.
Speed ometer calibration will be affected by the rolling circumference of the wheel/tire combination.
08-06-2005, 06:01 AM
#37
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Originally Posted by two rotors
I have checked all over my manual transmission and thereis NOT a speed sensor.The manual says the signal for the speedometer is taken from the ABS/TCM unit and the ABS sensors.The AUTOMATIC has a speed ensor in the transmission.
Speed ometer calibration will be affected by the rolling circumference of the wheel/tire combination.
Speed ometer calibration will be affected by the rolling circumference of the wheel/tire combination.
Anyone can confirm either way will be appreciated. Hopefully it is not stealing the thread - but it can change the top speed of the 8
!
02-04-2006, 02:44 PM
#40
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Wow 164? And with FI 171+? That's pretty fast. You have to remeber that wind resistance is only going to increase so it will take more and more power to gain every mph more than normal.
Oh and I think it's pretty easy to assume 180mph is possible on stock gearing. I know in 3rd gear 3000rpm = 30mph, 4000rphm =40mph , etc. and in 6th gear 4500rpm = 90mph, 3000rpm = 60mph, etc. This is pretty accurate I've found so far. so in 6th it would be logical to conclude that at 9000rpm it would be = 180mph.
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Oh and I think it's pretty easy to assume 180mph is possible on stock gearing. I know in 3rd gear 3000rpm = 30mph, 4000rphm =40mph , etc. and in 6th gear 4500rpm = 90mph, 3000rpm = 60mph, etc. This is pretty accurate I've found so far. so in 6th it would be logical to conclude that at 9000rpm it would be = 180mph.
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Last edited by dmorales; 09-09-2011 at 02:30 AM.
02-04-2006, 09:29 PM
#41
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Well the 6th gear is definately governed in America....I hit 161 on the speedo running way into the redline in 5th where it's getting ready to touch 10K....then shifted into 6th and the car felt like I had downshifted and not rev matched...went down to 153 then I realized I didn't do anything wrong...kept on the gas got it to 155 mph....and it just stood there....was even going downill in 6th at 155 and it just kept staying there....tryed the run again same results....
took almost half a tank of gas to do all this =)
took almost half a tank of gas to do all this =)
02-05-2006, 02:56 AM
#43
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Well it would bounce rev's between 9.7-9.9K .....though I was pretty sure I was gonna blow it =) made the whole ugg ugg ugg sound when you shift to late in an earlier gear =)...cept it kept making it till I shifted =)
02-05-2006, 10:07 AM
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Maxed out
I have a greddy turbo kit installed and tanabe cat back. The car maxed out in 6th gear at 172mph... this is bouncing off the redline. Unfortunately this is off the speedometer in the car, as i didnt have GPS with me, so my overland speed may have been faster.
02-05-2006, 10:09 AM
#46
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Originally Posted by auwen
i didnt have GPS with me, so my overland speed may have been faster.
but thats cool. finally a more definitive REAL answer.
02-05-2006, 10:15 AM
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Speed
No I think i mean faster, the speedo measures revolutions. At high speeds the tire is going to expand due to centrifugal force. So at a static RPM a smaller tire circumference(which is what the speedometer is calibrated to) = slower than a larger circumference. Obviously the size gain from this is negligible so at max it may have made a 2-3 mph difference.
02-05-2006, 10:23 AM
#48
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sorry if i sounded rude earlier.
what you said is true, but you also have to take into account that with the huge wind resistance that the tires are slipping a little bit on each rotation, & thats a lot of rotations. i would have thought that the centrifugal force would be greater than the slippage, but i have ALWAYS seen speedos read higher than gps units when doing top speed runs. i have never done such a test myself, but have seen data from many other people, so i could be wrong.
what you said is true, but you also have to take into account that with the huge wind resistance that the tires are slipping a little bit on each rotation, & thats a lot of rotations. i would have thought that the centrifugal force would be greater than the slippage, but i have ALWAYS seen speedos read higher than gps units when doing top speed runs. i have never done such a test myself, but have seen data from many other people, so i could be wrong.
02-05-2006, 10:27 AM
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I didnt think about slippage... I guess the only way to find out would be to test it with GPS. Which will never happen... one time at that speed is enough for me till I get a rollcage and 4 point harness installed.