Gears and MPH

[smp3000]

I was just wondering from all my other Turbo guys out there what MPH are you at when you shift from 2nd to 3rd?

I'd say my average MPH at the very top end of 2nd is 58 MPH of course at max boost (6psi) and probably at 6900K



(werd)

 

[MP3skaterNC]

isn't that around the same mp3 grassroots motorsports got for the tops speed in 2nd gear. im around there too n/a. i don't think the turbo would make you get any faster on the gears, just go through them alot quicker.

 

[1sty]

I have no idea, with 8 PSI you basicly hold on for dear life as you get pulled all over the damn place in 2nd.

 

[MP3skaterNC]

always fun, ill be doing that soon hopefully

 

[IS300GTE]

more hp won't allow a higher top speed in any gear, unless you are in your top gear, and were drag limited (the previous hp that you had could not over come the windresistance, hence you topped out due to that) but it will allow you to accelerate to that top speed in whatever gear faster.

do raise a mph in a gear, the actual trans gearing has to be taller, or the final drive ratio would have to be lowered, or larger tires and rims could be added to do the same, you'd just have to make sure the overall ratio made the tire taller.

of course with any of this, you will probably have an inaccurate speedometer.

the other way to go about it would be to raise the rev limiter on the vehicle. here is a javascript program to do your own calculations if you were to alter any of the parameters i mentioned above.

you need to know your tire sizes, rim size, gear ratio and front diff ratio, let me know if you have any other questions



http://www.sgmotorsports.com/mph.htm#GearSpeed

 

[70]

I found a website with a similar program that tells you what speed you are doing in any gear at just about any rpm...

It's cool because you can change each individual gear and see how that has an effect on your speed at a given rpm.

I'll find the link and post in a little while.

 

[Gyre]

Speed calculator ... if you know all your gear ratios

http://www.302cobra.com/stuff/topspeed.html

 

[70]

The gear ratios for a 3rd gen Protege are:

1st - 3.307
2nd - 1.842
3rd - 1.310
4th - 0.97
5th - 0.755
Final drive - 4.105

and just for fun,
Reverse - 3.166

The Mazdaspeed Motorsports pieces are:
3rd - 1.350
4th - 1.108
5th - 0.975
Final Drive - 4.833

Now have fun...

 

[WShade]

It's not accurate, close, but no cigar. All gear ratio to rpm relationships are linear. For example, if you are going 20mph at 1000rpm in 5th gear, and your maximum engine speed is 7000rpm, then you theoretically can go 7*20mph in 5th gear, which would be 140mph at 7000rpm. Check it out next time your cruising down the highway. Check your speed at 2000rpm, then push it up to 4000 and your speed should be double. Just an on the fly technique.

 

[Gyre]

You forgot about rounding. It's only showing to the nearest MPH but the calculations are done more accurately than that. It is linear.