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Discussion Starter #1
Hey guys,
Could someone with the Zetect and an MTX-75 tell me how many RPMs your turning at say 75mph in 5th gear? I swear that my car runs at a higher RPM since they installed the new tranny, and 5th gear pickup is much better. I am also getting about 20-30 miles less per tank of gas. I broke the new clutch in properly, and the new tranny has apporx 1300 miles on it.

Josh
 

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409 Posts
I don't know anyone with the MTX upgrade, but the reason for the changes happening in your top gear
acceleration change and lower gas mileage is that
you've changed the gear ratio in your car. When
I had a '70 Cuda I put in a 3.91 rear end (the same job as the unit you purchased) which made the
gear ratio change. Instead of getting into the
math, a basic explanation is you did the same thing as making the tires smaller in height or
having someone put smaller gears in your tranny.
(you will have to rev higher to get to certain speeds) It makes your available power rev into
the power band quicker and makes the engine work
less for easier acceleration. On the down side
you will get lower gas mileage and your speedometer will be off a few mph. The gear ratio
is a simple equation of revolutions going into the
unit to revolutions going out of the unit. If you
know anything about the old muscle cars, you will
remember Dana rears selling the 4.11 "pumpkins" -
that is what they called the unit that the drive shaft attached to which spun the axles. It is the same type of unit that you have, yours is for
a front wheel transaxle.
 

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You Can't Make Me Laugh
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4,566 Posts
Why doesn't this guy get the "Iceman" ban?
I mean, really dude. Why are you worried
about anything Focajet realted when you owe
people here money?

Get your freakin debt paid off and then worry about where your tranny revs too.

[ 12-03-2002, 05:45 PM: Message edited by: KonaZXIII ]
 

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Inheritly Sinister
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Originally posted by dj_kurruption:
I know that 70mph in 5th is 3k rpms, and 90mph is 4krpms. So 75 should be around 3250...
<font size="2" face="Verdana, Arial">I though it was 3k at 72mph. Eh, close enough.


[ 12-03-2002, 06:18 PM: Message edited by: Egz ]
 
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