Varius Brat questions

[raging squirrel]

I am looking at a trio of Brats, if I recall they are early models. Now that they are available I will clear out the tumbleweeds and verify the years. I am hoping one is the 1981 model because of the ea 81 engine. If not, I will swap one in. My goal is to build a long range traveler. I need max mpg with only mild performance gains. I already have an "extreme" type 4x4 project, so no massive lift is planed. I do plan to design some sort of air suspension for increased ground clearance when needed. I did this with a 64 ranchero and was pleased. I have a few questions pertaining to my goals:

1)Induction- I am looking at 3 options: Weber 32/36 carb (heard good things), CV carbs from a large motorcycle ( I have seen this double the mpg on a snowmobile), or efi. I am not convinced about efi always giving any improvement in mileage. My 2 Ford f-150's are a good example. The 1981 had the carbed 300 six cyl. and no overdrive. The 1991 has the efi 300 six cyl. and overdrive. The 91 has no better power or mileage. Efi wins for convenience, but not always mileage. How about in the Subaru world?

2)4 speed vs 5 speed. Any mileage improvements with the 5th gear? How much? Driveability at higher speeds?

3) Increasing compression: do the ea71 (1600cc) pistons actually fit the ea81 rotating assembly for a boost in compression? How much of an increase? The ea81 is supposedly a stroked ea71 with improvements,

4) Other torque/mpg mods? I already plan either a 1 3/4" dual or an 1 7/8" exhaust, 2wd distributor, and electric fan.

Thank in advance!

Edited January 9, 2011 by raging squirrel
spelling error

[edrach]

I can only address three of your questions from personal experience.

 

The weber 32/36 carb is a significant improvement in driveability. I can't confirm an increase in gas mileage since I loved taking advantage of the increased torque. I think if I could have driven more conservatively with it, that there would have been a mpg increase with my '84 Brat.

 

The 5 speed conversion is certainly an improvement since it drops about 500 rpm off your cruising speed on the highway. Again, I didn't see better gas mileage, but that's just my driving style.

 

Torque cam from Delta Cams did improve low end torque and pickup. I don't have any data on mpg differences. http://deltacam.com/camshaftgrinding.php

[hanyou]

Coming from a bad Hitachi, my mpg went up by 10 (should have been more but it isnt tuned in just right yet). I highly recommend putting one in, especially if you can find one used (I paid around $350ish for the full kit, used in another state's craigslist was $50).

 

That being said, this looks like a good thread for another question... What is the nut size for the brake drum/rotors on the brat? I am thinking 1 1/4" but would like to know for sure before buying another socket. Definitely bigger than the 32mm I had lying around.

[HATCHY]

Same here edrach. Its just my driving g style. I noticed less MPG when I Goth Weber. Because its hard to stay out of It. Just my driving.g style to. I need a 5 Sp though big improvement

[edrach]

Coming from a bad Hitachi, my mpg went up by 10 (should have been more but it isnt tuned in just right yet). I highly recommend putting one in, especially if you can find one used (I paid around $350ish for the full kit, used in another state's craigslist was $50).

 

That being said, this looks like a good thread for another question... What is the nut size for the brake drum/rotors on the brat? I am thinking 1 1/4" but would like to know for sure before buying another socket. Definitely bigger than the 32mm I had lying around.

EA81 and EA82 cars the socket is 36mm; EJ cars it's 32mm.

[Crazyeights]

Yes the EA71 pistons do fit in an EA81. I just built mine with a NOS set. I have heard that the EA82 (SPFI) pistons fit an EA81 also and are an even better choice for compression. The Delta cam is certainly an improvement, but your valve train may be considerably noisier even with tighter valve clearances if it's a solid lifter engine.

 

You can also remove about .005" from the deck of the engine block halves and another .020" from the heads (make sure they are the large valve heads). Any more than that and the intake manifold may have to be modified to fit.

 

GD's SPFI conversion is great! I have never tried a Weber carb setup on an EA81 so I can't comment on that. If I keep my foot out of it I get about 18-20 mpg city and 25-30 mpg on the freeway. That's with 15" pugs and a 3.9 ratio D/R FT 4WD 5 speed.

Edited January 9, 2011 by Crazyeights

[raging squirrel]

Thank folks! I am pretty excited. The early brat is an 81! There is also a complete 85 model. The 82 is trashed (T-boned hard). There is even a topper! I have struck a favorable deal for all three ( I was told that I had to take them all) and am well pleased. It looks like I will have 3 engines to work with. I noticed that one had a decal stating that the valves do not require adjusting. Hydraulic lifers started when? I intended to ask for opinions on the later (82 and up?) heads with the bigger intake valves also. Port velocity versus flow. I am not sure which will be better for my personal needs.

It appears that I don't need to convert the 81( the one I intend for a daily driver) to electric fan, it's already there.

I am leaning toward the Weber carb right now, but still considering the efi since it is below zero here right now and I remember some of the issues I had with carb icing on the ranchero.

Anyone else?