ok...i have an 02DX 2.0l protege. problem is...theres no tach. so i was wondering what the redline is in each gear as in MPH.

1st--------**mph
2nd-------**mph
3rd--------85mph
4th--------***mph
5th--------***mph

peak torque is at 4000rpm, so i am wondering what would be a good shift point? winding it all the way to redline would put me right at the peak, if not then a little after (estimating), so should i shift at peak HP or peak TQ?

 

Torque = 135 lbs/ft @ 4000 RPM

HP = 130 @ 6000 RPM

Redline = 6500 RPM

If you shift at redline, you'll be beyond your power peak.

To calculate MPH from a given RPM:

MPH = RPM/overall gear ratio(wheel diameter, in inches)

then, divide that figure by 336.31

To find the overall gear ratio in each gear (1st through 5th) see TheMAN's FAQ.

Reference:
The Design and Tuning of Competition Engines, Fifth Edition, by Philip H Smith, page 459

 

ive never read on a forums yet until now... that someone had a reference for the information givin

that is one smart ma-fa right there

does that also work motorcycles?

or other toy mobiles?
(excluding marine (water) mobiles)

 

Yes, that formula will work for motorcycles also.

 

Yeah, that sick, thanks for the info, I'm gonna bookmark this!


P.S. Goldstar, where in Jersey are you....?

 

I live in northern NJ near Parsippany.

 

no one will just say :he, first is 35 and second is 50"?

 

Goldstar just curious where you get the 336.31 number?

 

Why dont you just get a tach ???

 

http://web2.airmail.net/theman/protegefaq/

The above link will take you there.

 

Could you put the formula in proper mathematical notation, and then run through it for your car in fifth gear as an example?

 

Sounds like a plan, huh mac?

 

Okay, I think I've got it. There was a problem with the original formula, as you are supposed to use overall tire height (as opposed to wheel diameter alone). I thought something about it didn't make sense.

Please see the attached and let me know if anything about it seems funny. Of course, our cars will never pull redline in top gear. Even with the mods I've got, the absolute most I figure I could pull in top gear would be 5500rpm or so, give or take. That's good for just about 125.

The gear tables at TheMAN's FAQ are great if you want to build your own table in Excel and plug in some values.

In my attachment, the formulas are even called out for you in dialogue boxes.

 

you = hero

to the tach guy - buying a tach? well, its like 100$ that i dont have and 5" of rice i dont need besides, i cant find a dash/gauge replacement for it.

 

In defense of the tach idea, they are a lot cheaper than you might think. And, you can get them in rather small sizes (down to 2 1/16", I believe). Plus, if you have any racing ambitions, a tach is a real good idea. A serious racer doesn't even need a speedo. How the car is responding through corners and what the engine is doing is far more important in that respect...