And by the way, you should explain what you mean exactly, do you mean the top speed of a stock si, a turboed si, a nos si, a si with lots of engine and head work etc. I would assume all the answers you would get would be different, because everyone has different mods/stock whatever.
I hit 140 on I-59 at about 3am in my 2000 Si. It was right at redline and I had a bad feeling about hitting my rev limiter on somewhat hilly road. Well, maybe it wasn't really that hilly, but at 140mph, even really gradual interstate turns scared the hell out of me. How long did it take you guys to get up there? I didn't time it (and now I'm a little too scared to do it, b/c that is 'pull you out of the car, handcuff you and send you to scary county jail' speeding), but from 120-140 it seemed like forever.
I'm not sure what it was on a radar gun, and I thank my lucky stars I didn't find out that night.
i have hit 140 on the speedo as well at 7,800 rpms i had one other in the car and some stuff in my trunk,it got there pretty quick becuae its was a very slight doen hill free way i would say about 2 miles to get there.
Mods: AEM CAI, Koni Yellows, Eibach Pro-Kit and Comptech Sway/Tie Bar Kit
Drag limited top speed of a STOCK civic SI is 127mph.
I dont give a rats ass what your speedo says, a stock SI is going to fall within 2% or 2.5mph of 127mph for its top speed at STP (standard temperature and pressure). Its all about math and science.
Drag: The retarding force exerted on a moving body by a fluid medium such as air or water.
The horsepower of a stock SI at it's stock gearing can only push the body of the civic against the friction of the air to roughly 127 mph. The only things that will chage this is: Temperature, Elevation & Track Pitch(running down hill).
The 127 number is generated at 0 degrees celcius (32F) and at 1 atmosphere of pressure (sea level). So, if you're driving above sea level or if you're driving in above freezing temperatures, your results will go DOWN! Face it boys, your speedo is wrong. Learn the science and quit the BS.
Umm.. Ok.. No reason to be a prick about it. I look a little math and a little science. Where do you get the drag coefficient for this? I mean if it is all about math and science, how about you drop some?
Besides, how am I supposed to know the stock speedo is off by a solid 13 mi/h? Maybe I can use that to get off of a ticket. Obviously it must get progressively bad as it gets faster, eh? Well, at what point does it begin to become inacurate? (and I don't mean by 2 or 3 mi/h) The speed and tach seemed to move pretty linearly.
Mods: AEM CAI, Koni Yellows, Eibach Pro-Kit and Comptech Sway/Tie Bar Kit
Cd=.31
Final Drive Ratio=4.40
Speedo errors exponentially.
The law doesn't care what your speedo says... the radar gun rules.
I don't mean to be a prick but this topic is OLD NEWS. Thats why I said to use the search function. Instead, the BS starts flying again. This is the main reason I hardly ever post on this page anymore. The SI forum in SHO has gone to hell.
So by either increasing horsepower or changing the final drive ratio (or reducing the coefficient of drag, which is the least likely I would figure) you can increase top speed... Makes sense. What is the formula?
I didn't mean to come off snappy, but it did seem a little harsh. Knowledge gained, 'priciate it.
I hit redline in 5th gear at VIR back in February. I was running on 205/50x15" which is about 1/4-1/2 shorter than stock. My speedo was pegged at 145mph.
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