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I have a 1980 brat, 1600, single range 4wd, and I top out at 85. I want to get a little more out of it than that. I think i have 3.90 gears, but am not sure. I can get my hands on a 3.70 rear diff. i think but would it work if I took out the front axels, and ran it in 4wd, making it rwd? What gears did subaru make?

 

~thax, James~

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Top out at 85 because your engine is at redline, or top out at 85 below redline, but the car can't go any faster?

 

If it's the former, then you could MAYBE go for higher gearing. Does your 1600 have the starter on top or the driver's side? If it's the top, then you'll have a LOT of work ahead of you to make an EA81/82 tranny work. If the starter is on the driver's side, then a tranny swap might be easier.

 

I'm still learning my Gen1 cars, so I dunno if maybe Subaru changed to the later tranny for all cars in 1980 or just the new Gen2's.

 

Now... if it's the latter, then sorry, but that's as fast as your car can go. Putting taller gearing in it could actually make it SLOWER because the engine will have to work harder to maintain that same speed.

 

My Legacy, for instance, can do 112 mph, just like all the magazines said it could. Not because it's bouncing off the rev limiter (it's sitting around 5k at that speed) but because that's all it's got. It's using all its 130hp to approach and maintain that speed.

 

If you wanted speed and horsepower, you shouldn't have bought a Brat in the first place ;)

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Tops out because it is at redline. Starter is on the top. to swap the tranny I would have to cut out holes for the shifter and don't want to do that. I was thinking about just running it in 4wd with out the front axles, thus making it rwd. The question I have is if I change the rear diff. to do this, would every thing fit right in place or not? I have plenty of power to push higher gears. I'm not really looking to go fast, the speed limit is only 65 mph in Oregon, I'm just tired of having to take back roads everywere to get good gas mileage. It was suggested that I just get bigger tires, but I just put $380 worth of TOYOS on original alloys I found, bigger tires are not in my restoration plans.

 

~james~

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yes it will bolt right in...

 

although i think it'll be a slug with 3.7's...

 

if you want something like that and don't mind running 2wd i think you should look for a 2wd trans from a gen1 coupe or something... some of those are 5speeds... and that'd solve your problem since you'd get an overdrive gear...

 

i also think your speedo might be off... or mine is... my brat used to top out going 93mph...

 

and the 5speed should bolt right in... then just don't run a driveshaft for the back and leave your rear end in... if you practiced a bit i bet you could change out the trans when you wanted 4wd pretty easy...:)

 

now that i think about it the 5speed might even be 3.7... i'll look in the fsm tomorrow...

 

Good luck!

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c'mon, isn't there anybody out there that can help me out.

 

~James~

 

Yikes,you gave the board five hours and one minute before you got upset???

 

 

Personally,my '78 does 90mph with the same engine and tranny you have.It also gets around 30mph right now but does even better when tuned up and no exhaust problems.

 

Good luck.I don't recall any other gearing from the 70's available.If you find an FE tranny and want to go FWD only then you're all set.You'll get the mpg and go a little faster.

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Yikes,you gave the board five hours and one minute before you got upset???

 

I'm not upset, and your right i should have waited a little longer, sorry. Thanks for the info guys, I think I will get that 3.7 and put that in.

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you would probably be better off with a 2wd 5-speed. The final drive on them is already 3.7, 5th gear is 0.725 vs .769 for the 4th gear on a 4-speed. Also the 5-speed will make a lot better use of the powerband.

 

Oh you can't simply remove the font axles and still got down the road. You will need to leave the outer CVJ in the hub and they're not easy to seperate from the rest of the axle assembly.

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you would probably be better off with a 2wd 5-speed. The final drive on them is already 3.7, 5th gear is 0.725 vs .769 for the 4th gear on a 4-speed. Also the 5-speed will make a lot better use of the powerband.

 

Oh you can't simply remove the font axles and still got down the road. You will need to leave the outer CVJ in the hub and they're not easy to seperate from the rest of the axle assembly.

 

Yes they do! I used a big hammer and just pounded them off the ends of the axles. Now reuseable... thats a different story:grin:

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BIG HAMMER..... YAY.... Hasnt anyone heard of the drag coeficant or sumthin like that... Basicly it goes as follows: Nomater how steep the hill your going your car will not exceed a certain speed, UNLESS, you give it more power! Basicly if you dropped it off of the empire state building.. it wouldnt exceed that speed... kindof...not.. you get the idea!

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Yes they do! I used a big hammer and just pounded them off the ends of the axles. Now reuseable... thats a different story:grin:

 

That's what I was thinking, but the fwd 5 speed is sounding like it might be a better choice than trying to run it rwd.

 

~again, thanks eveyone~

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Well, first off, your front hubs need those axles installed to keep themselves together. If they just sit there with no axles in them, you'll destroy the wheel bearings, in probably less than 1000 miles.

 

Now, you COULD just take the outer axle stub apart from the rest of the axle and stick it in the hub and put the castle nut back on it, and that would take care of that problem...

 

But... as for the rest of the drivetrain:

 

You could wear out your 4WD mechanisms in your transmission prematurely. One of the more knowledgeable guys can say for sure, I could be wrong.

 

I would also say that you'd put extra strain on your rear diff and axles, because now they're dealing with 100% of the engine's power instead of just 50%. But... we're talking about a Gen1 that has around 60-70hp in the first place, so that might not be that big of a deal.

 

Why do you want to go RWD so bad?

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You could wear out your 4WD mechanisms in your transmission prematurely. One of the more knowledgeable guys can say for sure, I could be wrong.

 

The 4wd is engage by a syncro just like the rest of the gears. The only prolonged problem I see would be premature wear of the rear main-shaft bearing due to uneven loading.

 

I would also say that you'd put extra strain on your rear diff and axles, because now they're dealing with 100% of the engine's power instead of just 50%. But... we're talking about a Gen1 that has around 60-70hp in the first place, so that might not be that big of a deal.

 

Why do you want to go RWD so bad?

 

The Datsun 510 and 240z use the same rear diff without any problems.

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I had a 1400 gsr down under and i topped it out at 115mph with the standard 4 speed mind you i was pulling about 7500rpm. as for a transmission a 5 speed 2wd is what you need, my current gen 2 brumby has the 5 speed 2wd box and it pull 2400rpm at 63mph, 100kph down here

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