swap automatic to 5 speed

[ABerlandi1]

im new to this site because i've looked everywhere and i can't find the answer. im a girl with a 98 spyder 2.4 auto. because of the poor gear ratio im dying to change to a 5 speed but im unaware if a 2.0 5 speed tranny and setup will bolt up and work with a 2.4 engine. (bolt pattern, flywheel, etc)

 

[crusada]

If i recall correctly the trans from the 2.4 is similar to the 2.0 trans obviously making sure you get the fwd trans and not the AWD. Someone correct me if im wrong though please. I think this was brought up in another post to.

 

[Absit]

Before you go swapping everything in your drivetrain, what exactly are you hoping to accomplish by this swap?

 

[crusada]

She stated because of the poor grear ratio and ill agree they are turds

 

[Absit]

If you'd let her answer, that'd be cool. "Poor gear ratio" is rather generic. What's the actual goal?

Edit:
Swap compatibility information found here:
http://www.dsmtuners.com/forums/newbie-forum/396346-transmission-question.html

 

[ABerlandi1]

to shift gears ..change it up , do something different

 

[Absit]

It'll be cheaper to just buy a car that's already manual.
That said, the information you need is in the link I posted.

Either way, your car will be screaming down the highway, that's just how DSMs roll.

 

[crusada]

You beat me to it i was getting ready to post that for her to read. I wasnt trying to be an ass by saying what i did earlier but im assuming she wanted better take off and to control her rpms but thats all just assumption

 

[ABerlandi1]

well my dads a mechanic so i wont be paying for labor just the car to swap thanks for your help

 

[Absit]

Yeah, just the parts will be sufficient to not justify the swap versus just buying the right car.
But good luck.

 

[91stocker]

Yeah, just the parts will be sufficient to not justify the swap versus just buying the right car.
But good luck.

Agreed, exact reason i sold the 5spd car for an auto. But awd is a little different, extra expense in the changing the rear diff.

 

[ABerlandi1]

So we did the manual swap already and one reason I changed from auto is because the gear ratios terrible. Now its worse at 70 im at 3000 rpms. I don't know much about the cars but I've looked everywhere online for an answer to why the hell its like that but i've had no luck any answers?

 

[DSM1G90]

The secret here is the power output, or simply "the twist power" from the motor .. in which it is called "TORQUE"..and addition to this "TORQUE" is what's called "the Final Drive Ratio"

We must not think of Horsepower, but TORQUE is the real key part in this equation.

Simply put: a 4cyl car needs a high final drive ratio for the low torque output of the motor to operate the vehicle effectively. That is why the tach shows 3Krpms @ 70mph - the motor cannot run at a slower rpm to operate the vehicle, and even the motor's output effectively at that speed. There must be a balance in power.


The 4G64 motor has 140HP output, but the torque range is only at 141 ft/Lbs @ 6000rpm. Almost a square motor.

Actually, 70mph @ 3Krpms HAS to be since the weight of the car being close to 3000 lbs and any 4cylinder motor JUST doesn't have the torque to deliver any high power to the wheels and to move the car effectively. Thus, the tranny has to match what the motor can give out for the car to operate effectively.


Thus, to compensate, the final drive ratio has to be above 4.00:1 so the motor's torque range can match the combination of the weight of the vehicle and tire rpms so the motor doesn't self destruct with trying to move something that it simply can't do, or overwork itself to death running at high RPM's all the time. Their has to be a balance..and this is what auto manufacturers have came up with with what they got..called a 'tradeoff" - a small output motor needs a high geared final ratio to balance things out. .. can't get away from that.

Like my Laser: I have a final ratio of 4.15:1 and @ 70mph (and I'm 190hp and 203 ft/lbs @ 5000RPM's) , I'm also sitting at 3Krpm's at that 70MPH speed. and the NT motors (both the 4G37 and 4G63 NT) manual trannies have a final ratio of 4.22:1 due to the less powerful motor (the 4G63) of 131HP and 133 ft/lbs of torque, thus they raised the final ratio to balance with the less torque range of the NT motor torque output.

Now, I've heard that manual trannies can be rebuilt with a changeout in the final drive gear ratio to reduce the final output a few points, but that really changes the whole complexity of effective shiftpoint to get the most effective power output. In other words: a huge tradeoff between power and economy.

With this change, you'll get the lower RPM's at highway speeds (maybe like 2400Rpms @ 70MPH) BUT, you're in the gears a lot longer and it will take a longer time to get out of them so you won't lose the required torque output effectiveness. Plus, that's putting a bit of extra work on the clutch just to get the thing rolling from a light and extra clutch wear is going to happen.

Sure, it'd be nice if we had 2.78:1 final ratios in 5th gear so the motor is just barely turning while wizzing down the freeway at 80MPH, but the motor is actually suffering running that low in trying to produce so much output power.

Sure, if you had a Chev 350 V8 under the hood, then you can easily drop the final ratio down to 3.08:1 since the motor has over 300 ft/lbs for torque to easily handle a 3000Lb car at a lower final ratio.

(Good luck fitting that motor under the hood ... )


Just one of those things when one owns a 4cyl vehicle of any make, style and size.

Good luck as always, and welcome to "Tuners"-DSM