Terminal F/E; What's yours?!

[nbleak21]

Originally Posted by Ecky

Swapping out my transmission for one from an Integra LS would allow me to go ~21% faster at the same RPM in 5th, or cruise at the same speed with 17.5% lower RPM. Another way of looking at it, I could do 56mph at the same RPM I run now at 45mph.

I know they make an F/ H2B conversion kit, but I wonder if they make a b2H /F kit... That would drop your final ratio even more!

[arcosine]

.68 gal/hr @ 2400 rpm @ 76 mph = 111 mpg

[serialk11r]

Originally Posted by Ecky

Going from 45 (2500rpm) to 55 (3000rpm) results in a cruising gas mileage drop from 48 to 38 - that's almost a perfectly linear drop, 21% less FE at 22% higher speed. From 55 to 65mph I go from 38 to 32, which is an 18% drop at 19% higher speed. My gas mileage remains around 48 from 45mph down to about 20mph.

Swapping out my transmission for one from an Integra LS would allow me to go ~21% faster at the same RPM in 5th, or cruise at the same speed with 17.5% lower RPM. Another way of looking at it, I could do 56mph at the same RPM I run now at 45mph.

I think that's about the same as my car. Might've been a very slight downhill grade, but 26.x mph (1500rpm ish) was 55mpg, 45mph (2500rpm) is like 48, 55mph (3000rpm) is like 38, and 70mph (3800ish) was like 30? 32? something like that.

Swapping out my transmission for the base Corolla transmission would get me about 10% lower final drive and 10% lower 5th gear for ~20% less revs at the same speed. Getting a 6 speed C60 would either get me ~5% higher revs (Lotus Elise has the same ratio for 6 as my 5, but they have bigger tires so their highway rpms are actually something like 2% lower!), or it would have the 6th gear that gives 10% less revs, but C60s run 2000 dollars or something like that. My standards for quietness and comfort have dropped to the point where I would be extremely happy to have just the 5th gear changed and be able to do 55mph at 2700rpm instead of 3000. Pretty big difference in noise.

If a girl complains about the noise, gonna order a new gearset immediately, Until then, I'll just try to think about all the gas I'm saving on 25mph roads by being able to use 1500rpm instead of 1800 and try to forget the extra gas that's disappearing on the highway >_>

Originally Posted by arcosine

.68 gal/hr @ 2400 rpm @ 76 mph = 111 mpg

Nice! The 1ZZ idles at 0.22 gal/hr I think, about 680rpm. Unfortunately, 70mph=3800rpm so I'm guessing 3800rpm no load would be well over 1 gal/hr.

[wmjinman]

The other day, I jacked up the rear wheels on the Jimmy and gave it a shot. Interestingly, cruise control wouldn't work. Maybe it has some sort of "smart" programming that knows the front wheels aren't turning - or that there's no load on the engine. (the ABS light came on eventually, so that's why I'm wondering if it "knew" the front wheels weren't turning).

So, very carefully with the foot throttle, I kept it at 50 mph for 2 minutes and got an average "trip" MPG on the ScanGauge of 48.2. I also noted it was at 1550 RPM.

I then did one at 2000 RPM (which the BSFC chart showed to be more efficient), and that one worked out to 65 mph and with one minute on the ScanGauge got 49.5 MPG.

Then I tried it in 3rd gear at 2800 RPM, the best RPM for BSFC. (I was afraid to spin the wheels that fast in overdrive, although I didn't notice anything (vibrations) to make me worried it was trying to hop off the jackstands). Of course, in 3rd gear, I was covering less "miles", so it was only 34.9 MPG.

I noticed the temperature was climbing during all of this, so I went back to 50 mph in top gear and did another one. This time, it came out at 52.8 MPG after running the "trip" on the ScanGauge for 1 minute.

About this time, the neighbor came over & asked if I was having "car trouble", so I figured I'd better quit this "horsing around" before someone else got curious/concerned.

After that, I went ahead and changed my oil & put Mobil-1 synthetic, 5-20 in it. Up until this time, I'd always ran Pennsoil 10-30, or maybe 5-30. So when I get the chance, I'll have to jack it up again and try the experiment again & see if there are any changes.

For the sake of safety, in case it "hopped off" the jackstands at 50 or 60 mph, I was parallel parked on the street in front of my driveway, facing down the street with no cars in front of me for several houses.... and I was IN the driver's seat while it was in gear. So I told myself if any mishap occurred, I could probably hit the brakes & stop it before anything "bad" happened.