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Is there a way to change gearing?I'm turning 4,000rpms @ 80mph...


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Pretty much as the topic says. I'm used to other vehicles which have much longer gears and a much lower 5th/freeway gear. 4,000 seems high to be turning for multiple hours on a freeway. Is there a way to change the gearing to bring this down some or is it just fine and I'm a lunatic?

 

BTW: The vehicle is an 1988 RX 3dr liftback, EA82T w/dr 5spd, stock 13" wheel/tire combo.

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I assumed as much, but I was just making sure that no one out there had performed a radical modification to the DR setup or the final drive ratio.

 

By Pugs you mean 15" Pugeot rims that match the stock wheel bolt pattern?

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While I drive an EA81 auto ive put the better part of 100k on my car at around 4500 rpm. No problems for me. Also those kit builders that use ea81's liek to gear it so that the engine is at 5000 rpm for the flight, as that puts it at the top of the power band and you get good fuel usage out of it.

 

Alex

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Pretty much as the topic says. I'm used to other vehicles which have much longer gears and a much lower 5th/freeway gear. 4,000 seems high to be turning for multiple hours on a freeway. Is there a way to change the gearing to bring this down some or is it just fine and I'm a lunatic?

 

BTW: The vehicle is an 1988 RX 3dr liftback, EA82T w/dr 5spd, stock 13" wheel/tire combo.

Hey targarose,

 

I have a '89 GL Sedan, DR 5 speed. I'm not ready to put it back on the road just yet so I can't run out and check it. With the 3.90 gear @ 4500 RPM or so, it runs 105 mph, in fourth. The tach may be off. Do you have it in low range? Under sized tires? Please report what you find out.

 

Q

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My XT is about the same, about 4k in 5th at 80. Let's face it, old-gen Subarus are small cars with small engines. To put a really tall gearbox in it would only make it slower and use more gas since the engine would have to work harder.

 

Like Turbone said, you can put bigger wheels on it, but that's about it. No other gearbox that will fit an EA is going to give you drastically longer gearing.

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First, the rpm/speed you list is about right. +/- a few mph depending on fine tuning. Upgrading to 15" Pugs can boost about 10%.

 

Second - why do you need to go faster than 80? Do the speed limit, live longer, enjoy the countryside. Don't be in such a big hurry. If time is that important, fly.

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First, the rpm/speed you list is about right. +/- a few mph depending on fine tuning. Upgrading to 15" Pugs can boost about 10%.

 

Second - why do you need to go faster than 80? Do the speed limit, live longer, enjoy the countryside. Don't be in such a big hurry. If time is that important, fly.

somebody's showing ones age again :rolleyes: (j/K) but I don't think 4 grand is that high a crusing speed for the engine
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Just back a few months ago I got a whopper. 87mph in a 70mph zone. Cost me $100 in court costs. Northguy, you may want to look at the calender for next month :-p

Oh, and sorry for the H/J :-\

 

3.90 gears make for a higher rpm, the 3.70 is better for hiway use.

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you shouldnt need to change the gearing.... subaru motors are designed to run at high rpms for long periods of time... in fact, i have noticed that the ones that are used in that aspect, last longer and run better- so I would just get used to it... (think of it like a sport bike! they run about 8000rpms for a crusing rpm :brow: ) cause your motor will run good at that rpm (besides, if you get to a hill, you will need it to be in the powerband anywyas to climb it)

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I agree. I get alot better mileage when I'm on the freeway. I think I'm doin about 75ish at 3500: 3.9 axel ratio DR 5sp. Kinda hard since the speedo sticks between 55 and 75. :banghead: So, 4K at 80 sounds about right.

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on the road trip the second time, the RX averaged a 500 rpm higher difference than trashwagon's part time dual range, but it got better fuel economy

 

in danny's loyale, h connected one of those vacuum gauge "gas saver" and as you increase rmp for the same amount of pedal travel, the needle moves up into the good and excellent. if you notice, say at 50-55 mph in 4th gear, there is less pedal effor than trying to keep the same speed in 5th at a lower rpm

 

3500-4500 rpm is optimum range for the ea82 motor, right smack in the powerband.

 

whenever i go baja'n in the field, the tach is always about 4500 to 5500 rpm all day, and the motor doenst complain one bit!

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whenever i go baja'n in the field, the tach is always about 4500 to 5500 rpm all day, and the motor doenst complain one bit!

I seem to remember it hovering around 7k for quite some time...

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The final drive of the RX FT 5speed D/R and the PT 5speed D/R are very close. Without all the math….

 

 

RX F/T 5speed D/R

 

5th gear ratio = .871

Final drive = 3.7:1

Tire size = 185/70HR13 (23.2” Dia.)

3268rpm @ 70mph

3735rpm @ 80mph

 

 

4WD P/T 5speed D/R

 

5th gear ratio = .780

Final drive = 3.9:1

Tire size = 175/70SR13 (22.6” Dia.)

3167rpm @ 70mph

3620rpm @ 80mph

 

 

These numbers seem to agree with my ’87 RX

Gary

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