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POTATO
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would like to see someone pull 161mph out of a 3.73 mk2, that'd be nice...
so far all I've heard was topping out at 125-135 in any particular mk2...
mathmaticly it should be possible
:?
 

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Tanya, I have run nearly 6000 rpms in 5th gear in my turbo '82 with a 3.73. Probably around 140 mph. Won't be re-visiting those speeds until I get the new brakes on.
 

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whew, I've pinned speedo @ 130 @ about 6000rpms w/ 4.30 gears which appears to be accurate comparing to the chart... I would like to see someone w/ a stock n/a mk2 "officially" top their car out @ redline and see what mph that would be...just can't figure out a way to get a speed check unless you have a cop friend who'll clock you, heh
or maybe an aftermarket speedo that does over 130? I dunno
I think Norbie has said he's done 160mph but that's definitly NOT stock...
all mag articles I read has the mk2 topped at 130mph, so is the car not supposed to pick up even a little more speed if it still has a few more rpms to go?
 

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well, i topped my speedo out sat on the way to daves house. this late 90's firebird wanted to play. so i downshifted to 3rd and nailed it and left him easily. the second time was quite a bit later. i didnt notice him get on it, and when i finally saw him he was passing me. i down shifted to 3rd again, then shifted to 4th while next to him and past him then shifted to 5th and was still pulling a little,not a whole lot. looked at the speedo and it was pegged. i was ~5500rpm's. i let off the gas and started braking. he didnt slow down, just kept on going. guess he didnt want a round 3. i know the speedo gears cant be right for the 4.30 gear, also i have 235/60/14's on it rigt now and am running an r154 so have no idea how fast i was going, just know it didnt take very long to get there.
william
 

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You'll never get anywhere near 6500 RPM in top gear with a stock (or near stock) 5M.
It just doesn't have enough power.
 

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well, that and the stock clutch will be slipping well before then. btdt
william
 

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ive topped out my 120mph speedo a few times, with the only mods 245/50 bfgs, and a 2.25 cat free exhaust.
 

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hmmm, i cant really claim a verified 5th gear max speed, however when i maxed out 4th in my 4.30 rear p-type the state trooper said i was going 110 mph.

that is going totally from him though since my speedo starts swinging back and forth pretty wildly after about 90 mph.
 

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Ross said:
120 is a lot short of 160 though
sure is, i was simply trying to make the point that 120 is easy, and i should have elaborated on that.

120 mph isnt hard, with a mostly stock, unknown milage low compression 82.

the problem with cars is, once you reach a certain speed, thats it, your aerodynamically limited, drag is equal to the forward motion provided by your drivetrain.
as you get faster, it takes considerably more power to go any faster.
look at modern cars and compare the gearing, power, weight, friction, and drag.
then look at their top speed.

usually, if you can find a car with everything else the same, except drag, your gonna notice a huge difference in top speed.

basically what my long rambling confused post is trying to say is that i dont think a mkII is possible of an honest 160mph without insane power.

its easy to read a speedo and say my car does 120 or 150 or whatever, but we all know stock instruments are pretty inaccurate.
anyone wanna go to bonneville and bring a hot supra?? :D
 

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Power goes as the speed cubed so if 161 hp gives u 127mph (car and driver top speed as i remember) then u need 161* (140/127)^3 or 216 hp
to get to 140 mph. prolly a little more hp required since wp losses prolly get horrific at 6500 rpm.
 

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According to StanS formula, how much power would it take to do 160 MPH with a 3.7 diff?
Just wondering, and too lazy to work it out myself.
I think that formula may be a little simplistic, as it doesn't take into account aerodynamics and drag, as mentioned by dogstar.
(I should have mentioned the drag myself, which is why I said it would take an awful lot of power to hit 161)
 

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OK I worked it out using StanS supplied formula = 328 hp
I still think it would require more than this though.
It's just a gut feeling, I don't have any proof, but I would expect you to need at least 350 and maybe 400 hp
 

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as it doesn't take into account aerodynamics and drag,
It does take aero and drag into account since the same car is used in both cases. It doesn't take non-linear losses (such as wp losses) with rpm into
account. I'm only guessing that wp losses are not linear i.e. double the
rpm and get more than double the loss.
 

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In fact the formula is solely based on aero drag. It predicts the power
required to move the car at any speed. Gearing has nothing to do with it. Gearing only keeps the motor operating in it's design rpm range. Gearing will require different motor Torque so the motor will produce the required hp predicted by the aero based formula.
 
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