Taller Gearing?

[porcupine73]

I think the gearing for the 4 cyls is selected pretty ideally. So yes ok maybe when you get up to 80 mph the revs seem kind of high but at that point you're in top gear and moving at a pretty good clip. These 4 cyls have ok power but they're not some torque monster V8 that has the power at low revs to turn like 2000 rpm at 80 mph either.

 

I switched my '96 Legacy 2.2L to Outback struts and tires and I do not at all like the gearing now. It shifts too early and for any amount of get up and go or encountering a hill I have to downshift to 3 or 2 manually or it feels like the engine is lugging. I don't mind shifting it like that, I like doing it, but to have the gearing be 'taller' in these things in my mind just wouldn't work out for a production passenger car.

[thatswhatshesaid]

Bigger tires is BY FAR the easiest/cheapest/fixable if you don't like the changes method. I have about 1.2" more diameter on my 2000 Outback (4.44 final drive) and it made a nice difference in my freeway RPM...

[porcupine73]

That's cool. I actually went the other way in my '00obw, with a slightly smaller by around .5" diameter tire, and like the way it shifts and runs better. It might have hurt my mileage a bit I'm not sure, but it just makes it feel like the engine isn't laboring quite as much.

[ydeardorff]

Im planning on using the stock gearing for the EJ20TT, as I will be using the stock motor and trans. But I will be running 19" rear wheels on low pro tires, with 18's upfront.

I figure that should lower those RPM's abit.

[thatswhatshesaid]

Im planning on using the stock gearing for the EJ20TT, as I will be using the stock motor and trans. But I will be running 19" rear wheels on low pro tires, with 18's upfront.

I figure that should lower those RPM's abit.

 

You better be putting a fair bit of sidewall on them 19s to make a difference...

But if you want a super quick car, the taller gearing would destroy your acceleration...

[ydeardorff]

LOL,

 

I think a 1800 lb car with 250 hp will sufficiently scare the piss out of me:)

Edited September 14, 2010 by ydeardorff

[johnceggleston]

Im planning on using the stock gearing for the EJ20TT, as I will be using the stock motor and trans. But I will be running 19" rear wheels on low pro tires, with 18's upfront.

I figure that should lower those RPM's abit.

 

if this is an AWD car and the front and rear tires are different sizes you will have torque bind, kill the AWD aspect of the trans and place excessive wear on the rest of the drive train.

[ydeardorff]

yes the AWD trans has to be shortened, and converted to 2WD.

It seems remarkably easy to do with Suby transmissions.

 

The real trick is to find a way to hook up the stock ECU. After market units are available, that also remove the rev limter etc, but arent cheap. The cheapest method is to find the answers on the stock ECU hook up.

Edited September 14, 2010 by ydeardorff

[johnceggleston]

yes the AWD trans has to be shortened, and converted to 2WD.

It seems remarkably easy to do with Suby transmissions.

 

The real trick is to find a way to hook up the stock ECU. After market units are available, that also remove the rev limter etc, but arent cheap. The cheapest method is to find the answers on the stock ECU hook up.

 

why not just install a FWD trans. some of the early ej cars had a 3.7 final drive in the FWD, i'm pretty sure. is that a "taller gearing"?

 

when you say 2WD do you mean RWD or FWD?? i don't know if manual trans can be converted to RWD???

Edited September 14, 2010 by johnceggleston

[ydeardorff]

yes the AWD gets the rear diff removed, then becomes a 2WD trans. Thats is in my setup, where the FWD output shafts become the RWD out put shaft in a rear engine setup.

Then flip the diff internally.

Once done, it fits intot he back of a bug chassis with little to no mods needed to the body other than a radiator. Even the shift shaft works out perfectly.

[SchwarzeEwigkt]

I just want to throw out there that these (and many) engines are both more powerful and more efficient higher in the rev range. Having a shorter final gear means you keep the engine in the efficient areas of the rev band with the added bonus of not having to downshift to accelerate. Having a stupid tall triple overdrive gear only works with engines that can keep the car moving down at 1200RPM. That's why you can get away with it on an LS7 Corvette or a Viper. They make huge gobs or torque basically from idle, so you can toodle around at 12MPH in 6th gear. They displace 6L and 8.3L respectively, though. They're huge. You can't do that with small displacement engines. Subaru engines generally are anemic below about 2200RPM and downright worthless below 1800RPM.

 

On modern engines, fuel efficiency is more about throttle position than engine speed. If you end up getting a taller rear end or huge wheels, you may end up reducing revs. The problem is, you very well might pull the engine out of it's efficient range, increase the need for downshifting, increase the need for standing on it to accelerate and, most importantly, suck the life out of your driving experience.

 

If you don't like listening to it, fix muffler, fix the exhaust hole or buy something else.

 

Not trying to be inflammatory, but there's a whole lot that goes into this other than just engine speed.

[ydeardorff]

Dont worry about that M8T! Its not being inflammatory at all!

In my quest to modernize this kit car of mine, I have been put back into my place time and time and, not because I over step my bounds, or pissed people off, but rather, I had became grounded again finding out what others had already known. or found out themselves.

 

What youve said is very true. And there are many different variables that contribute to a car working well, or not. Like the old addage says, speed costs, how much you willing to spend? Well, I know from my past projects, if you want loud, fast, and aggresive you better get a loan, and a gas card, cause youll need it.

 

My concerns arent as much on the performance of the car, but more for aesthetics. the absudrly light kit car with this much power will be down right scary at times. But I can understand on long drives how having abit lower revs, would help.

But if Im not mistaken, to properly change the revs, you have to plan out alot involving the cams, and crank. And then to what end, like you stated it is after all a 4 cylinder, not a 8-10-or 12.

Or we could all start a new thread, on changing the subaru legacy and imprezas to hold a supercharged version of the EG33 motor, then youll have tons of torque.