what kind of mpg can i expect to get with a single turbo 20b with 850 primaries and 1600 secondaries. what seems to be common if there is such a thing

 

I'm guessing 250-300klms/tank? If I really calculated it out it would probably gross me out!

 

converted (155 miles - 186miles)

 

on a completely stock one behind the auto trans I saw almost 18 mpg if I drove an entire tank at 67mph on the interstate. If I went 75mph (the limit out west) it would be more like 15.8-16.5 mpg. I am too poor to try any faster.

It only goes down from there.

I'd say I'm getting 10-12MPG in mixed driving.

 

just thinking of this makes my wallet hurt.

 

The secrect to getting better cruise mpg with a 20b and any larger displacement engine is to lower the cruising rpm's. This isn't gonna happen if your using the stock Rx7 manuel transmissions. At 75mph the rpm's will be at 3k. That's fine for a little 13b but not good for a larger displacement 20b engine. A 20b has enough torque to chug along at 2k rpm's all day long at 75mph. You just gotta find the correct gearing to get better results.

 

but that will cost performance.

a better option would be a 6 speed trans.

Adapter plate + custom input shaft or custom clutch behind a T56 would really be ideal, with a .50:1 6th gear and a 4.10 gear you get the best of both worlds.

 

Driving from Utah to Cali for Sevenstock in '08 I saw ~19 freeway. It really surprised me. I haven't bothered with around-town driving. My guess would be ~12.

(Ported w/42R, stock tranny)

 

I dont mind going 60 down the freeway until i get on it.

 

driving from norcal to socal for sevenstock in 04 i saw 19.9 freeway. mileage drops quickly with city driving, mine was all mixed, so i'd see 13-16mpg depending.

interestingly with the stock ECU, and the short gearing of the truck we took in 2005 mpg was like 8-9, the rpms are up out of closed loop...

 

so highway mileage is much higher than city driving so maybe this is like my friends viper he is getting 8-9 mpg which is where i might be with e85

 

I get 17 mpg on the highway with a lower-geared J-spec transmission. 10 around town. Quickly drops to single digits when having fun.

 

I get 18mpg on the highway at ~80mph with the stock TII tranny
I can get 15 or so on 2 lanes or in town, but if I have to stop at red lights or spend any amount of time at <20 mph, I get like 6-8mpg.
my setup is a ported engine with 42r, 850/1680 injectors

 

If you drove my car once, you would see why this is not an issue. First gear is useless with the power and torque of a built 20b. I actually think that I will get better ETs next time I go to the track by starting in 2nd.

Even in 5th I can break the tires loose if I want. (sticky 275s)
When I am driving in traffic I usually shift from 1st to 5th

 

On the interstate for 1 tank full with no boost I got 13 mpg. I'm getting 6-8 mpg around town.

 

i GET ABOUT 10 CITY, 16 HIGHWAY.

 

i saw a jc cosmo spec's page and it said that it gets 6.0km/l (city) and 9.7km/l (highway). and if you convert that it should be 14.1 m/g (city) and 22.8 m/g(high way)

source: http://www.dmrh.com.au/jcspecs2.htm

why cant people get that in a FC Tii, if you keeped everything stock and used the Tii manual trans?