n4ji

iTrader: (1)

For once Japan got the shaft on their own car, not the US!

NZConvertible

Yeah, all cars in Japan are legally required to be limited to 180km/h, and all have 180km/h speedos.

Luckily the FC's limiter is easy to bypass. Most later cars need ECU mods!

RXM307

how do you bypass it then?

skydivr73

and that means something WHY??

Look--horsepower is only one part of it all....you are not taking into consideration all the rest--traction, gears, weight? I could put a ton of hp into a car but the gears, the suspension, there are a lot of things that affect top speed, not just horsepower. So let's get real here...If there are people on here who can bust 120 or 130 in an NA that isn't even putting 160 to the wheels, then how the hell do you expect us to believe that adding 200 HORSEPOWER would only allow you to get a little more top end?? What about the power curve? You could set up your car for more top end or for more low end....and what about the DRIVER??

Go get a clue

NZConvertible

Have you read the whole thread?

No, you need to get a clue. Most of the thing you mention have no effect on top speed. Traction? No. Weight? No. Driver? No. The only things that are important here are power, gearing and aerodynamics. Most people make no positive changes to gearing and aero, so power is all that's left.

As I've already posted, you need to add massive amounts of power to get a meaningful increase in top speed. The physics is well proven, so you can't argue it. Do the maths yourself if you don't believe me. Plus since higher speed mean higher revs, the engine has to make that extra power at those revs.

You comment about people reaching "120 or 130 in an NA that isn't even putting 160 to the wheels" is meaningless, since I believe 125mph is the top speed quoted for a stock S5 NA making 160hp at the flywheel.

Brett "BBX"

There are no speed limiters on any RX-7's period...that is that...Mazda rotaries do not contain them.....They are not incorperated into the ECU's....Your top speeds are a combination of Mods, Model, Year made, and Fuel map in the ECU....

SideWindeRx7

well said, but im going to elaborate a little further. The reason it takes 160 hp to get to 130 and 400 hp to get to 180+ is because of aerodynamic drag. The faster you go, the more resistance is put up, hence the more power is needed. I forgot the formula, but depending on the aeordynamics of the car you can figure how much the resistance is and how much power is needed to overcome 1 more mph at a certain speed. Obviously at a low speed you wont need as much power. If this was not the case a 60 hp geo storm could go over 200 mph with the right gearing.

driver also plays no active part in a cars top speed. Suspension only stablizes the car, it wont affect the actual top speed. I would also like to see someone lose traction at 150+ (sliding the car and crashing dont count)

Technically a s5 NA is geared to go faster (top speed) than my TII that did 160+. Reason it cant, is because of power. power + gear = top speed
everything else is a safty procaution.

yallgotboost

back when i had my 1988 n/a i could hit 150 ez on the turnpike.

skydivr73

Like I said in the first place guys, Horsepower is not the ONLY thing that is needed!! I never said that it wasn't the biggest thing, but if you really think it is the only thing you need to go learn something.

DRIVER--in a way, this could actually have some bearing....if you do not believe me, then just take a look around this forum and see the posts that have been made by people talking about how fast they can go in FIFTH GEAR...then tell me that the driver makes no difference....anyone who knows anything about the FC knows that fifth gear is not where you hit top speed...

TRACTION--maybe this was the wrong term....I was referring to using tires that cant handle the speeds youa re travelling at(and YES, I have seen this happen more than once...ever see a tire just fly apart at 160 mph?? I HAVE)

WEIGHT....ok, so imagine an FC with about the same horsepower as a Vette.....but lightened. If you have say 800 pounds LESS in the FC, but the same top end power, are you really going to tell me that it makes no difference?? BULLSHIT

Besides, if you are talking about the pure top speed, that''s one thing, but if you are talking about the REAL WORLD, it is a little different....In the REAL WORLD, it is not just you, your horsepower, and your coefficient of drag. It is also whether or not your car can even handle what you are asking of it. I will GUARANTEE you that if you put a good driver and a novice driver in two identically matched cars, that the good driver will win a majority of the time. That is because the good driver has experience driving at those speeds. There is another thread on here about some guy trying to get his NA to be a 10 second car, and it is really funny, because all he is talking about is AERODYNAMICS....and everyone who replies to ths guy is telling him the same thing--forget about the aero cuz he is wasting his time!

Icemark

Please read the whole thread before posting.

If you did, you would see although there are no Speed limiters on North American RX-7s, there are in other places such as Japan.

So your would be wrong, because yes there are in some places.

NZConvertible

The driver has no effect on the capabilities of the car. If one person can drive the same car better than someone else, that's got nothing to do with the car. If a driver chickens out before top speed is reached, that's got nothing to do with the car.
Traction is the wrong term. You're talking about the speed rating of the tires. Again, that's not what is actually limiting the car's top speed.
Weight has no effect on top speed. If you think it does, you need to take some basic physics lessons. Weight affects acceleration, so if you lighten your car it'll reach its top speed a bit quicker, but it won't be any faster.

NZConvertible

Have you just not read anything in the thread, or are you saying all the info I posted is incorrect?

andrew lohaus

When will you guys realise that you can't trust the speedo at high speed. Bragging about your top speed is like bragging bout the size of your dick while looking at it through a magnifying glass. [/B][/QUOTE]

very true, the only true way to know is to calculate from your RPM, gear ratios and tire size, however i hit 140 on the speedo and the numbers worked out to almoust exactly the same thing.

andrew lohaus

[QUOTE]Originally posted by Nick86
[B]Check your brake fluid level - chances are it's low.

dude what does brake fluid have to do with the emergency brake, it a redundant purely mechanical (non hydraulic) cable. i have had the same problem you gotta go jimmie with the cable and ratchet mechanism on the rear hubs.

Icemark

[QUOTE]Originally posted by andrew lohaus
[B]The low brake fluid indicator also lights the brake warning indicator

venomrx7

you gotta go jimmie with the cable and ratchet mechanism on the rear hubs. [/B][/QUOTE]

Its always weird to see jimmie used that way.

My name is Jimmie, spelled the same way.

Peruvianrx7

iTrader: (25)

i hit 120 in 4th switched to 5th and it took 10 seconds for it to go 121 then 10 more seconds for 122 im not even kidding is this due to lack of torque?

skydivr73

If what you said here is true, perhaps you could explain why an airplane can hit a higher speed once it has burned off most of the fuel from its internal tanks....a military jet for instance....the only thing that changes as you burn off fuel is WEIGHT, and they have the same issue of aerodynamics to deal with....once they burn off half of the fuel, they have a higher top speed....just ask anyone who flies the planes in service today and you will see what I mean...

But you're right...this has nothing at all to do with it...and dont give us some **** about "it's a plane so its different..." Fact is, it isnt any different. Not when you look at it from a physics point of view. The one difference is that there is more resistance when dealing with a car, since it has contact with the ground as opposed to a plane, but that does not change the effect of weight

Elysian

my 87 turbo II didn't have a governor, i hit 150 in it in west texas racing a c5 corvette.... and my 88 rx7 i have now hit 140 easy(easier than the 87 hit 80)

NZConvertible

A plane uses it's engine power to develop lift as well as thrust. As weight burns off, more of that engine power is freed up to provide thrust, hence the higher top speed.

Cars do not need to develop lift. Quite the opposite...

But I wasn't entirely correct about weight. Weight does affect top speed, because it causes more drag from the tires. But does it have a significant effect? Are you going to increase your top speed by ripping out a bit of dead weight? Hell no. Read this; it'll show how tiny the effect of tire drag on top speed is.

The point is, you were arguing that there are other things to consider besides power. But for nearly every person here, the only factor that can be changed enough to make a significant effect on top speed (i.e. more than an extra 2-3mph) is power.

Besides power, the only other significant factor is aerodynamics. Most people are never going to improve their aerodymanics with add-ons. In fact most of the cosmetic body bit will more likely make it worse.

tecknomage

thease might help some one this is the US spec gage cluster there is not screw in it the spot i'm pointing at is ware it would go

Touya

I would take my 91 neer stock out and test it to get better idea of the speed, but my brakes suck, 1 of my tires is off balance, my alignment is shot, and I have 175k on the original enigine without a rebuild. But when I got the car I do know that I got to 120mph on the speedo with ease, if that is accurate, i was to busy wasting the couger with the body kit and toyo stickers that was then way behind me trying to keep up.

EJayCe996

Wow lol, old but interesting thread... That one guy actually really thought that weight had a bearing on top speed? HAHAH i'm 19 and i know it doesn't, it only makes a difference in how fast you reach your top speed.

KompressorLOgic

iTrader: (6)

with my 87 na with full exhaust, i hit 135 in 4th then i ran outa room..... this was a little above 7500 rpm or so. calculating the speed using gear ratios and tire size it says my speedo is pretty accurate.

shifting into 5th when going around 125 i started slowing down.... shifting right before fuel cut might, allow a little bit of pull in 5t, but who knows.....

WookeysRX7

not to revive an old and beaten thread but i sold my old 87 tII last year and i had no problems hitting 245kph and could have gone faster but who knows how accurate the speedo was.

But now i just baught a 1990 RX-7 Turbo from japan and i took it out and hit the govenor which was like you all stated 112mph or 185is kph. Now it was stated that i could remove a screw from the back of my gauge cluster and it will delete the govenor, but will this affect my speedometer at all? Like by how it reads/how accurate it will be? I mean below the 180kph speedo that i have.?

Thanks.