my FE thread

[gearheadcheapskate]

Aha! I've been waiting for a GSR owner to chime in. I've got a '94 w/109k; bought it brand-new 14 years ago. Up until fuel economy mode really kicked in a few months ago, it's had an odd combination of really easy life and all-out beatings. Literally thousands of excursions to the 8300 rpm fuel cut-off, 6+ seasons of SCCA autocross, a few times at the drag track,etc, etc, etc.

Anyway. I've got a lifetime average of about 32.0. In '01-'03 it saw a lot of highway use and turned in 33.5, 33.7, and 33.3, respectively. Since '04, I've lived 1.9 miles from work and it's been hard to keep mileage up.

I've put 4 tanks in it so far this year and it's obvious when the hypermiling started. 31.7, 35.7, 38.6 and 39.3. I'm headed for the big 4-OH on the next tank!

It's stock except for adjustable koni yellow's, hawk HP's, and sway-bar bushings, and ign timing.

Some integra tips:
1-advance the ignition timing. Most people won't do this, but I've had mine as far as the distributor would go (about 23 degrees BTDC at idle) for about 80k miles now. OBDI GSR's have a knock sensor, so it will retard the timing if it needs to, but the knock sensor only works below 5500rpm or so. I always use 93 so I'm not worried. Your off-idle tip in and below 1500 rpm torque will increase nicely with the timing here.

2- I've just disconnected the power steering pressure switch. This switch is down by the rack and idles up the engine speed during high steering load times. Since I've begun engine-on coasting, I didn't want the idle speed any higher than it should be. I haven't missed this feature in the least.

3-decel fuel cut-off is closed throttle above 1050 rpm. I'm in neutral unless I *must* stop, then I'll engine speed match a low gear and drag it down to 1050 for fuel cut-off.

4-neutral alignment: many racing folks will toe out the wheels for better turn-in. It works for that, but causes too much drag.


I'm trying to figure out what it likes best for acceleration- low rpm lugging or a higher-engine-speed with very little throttle opening. Any ideas?

Other ideas: break the power steering pump open and reduce the stand-by pressure somehow, chip the ecm and lean-out the low-load-small-cam ranges and further tweak timing (investigating this next).

Any others?

[EH3]

Originally Posted by gearheadcheapskate

1-advance the ignition timing. Most people won't do this, but I've had mine as far as the distributor would go (about 23 degrees BTDC at idle) for about 80k miles now. OBDI GSR's have a knock sensor, so it will retard the timing if it needs to

as a former honda tuner, this is not sound advice. there is no reason at ALL to advance the base ignition timing beyond OEM specifications.

obd1 honda's knock detection hardware is nothing short of worthless. frankly, it serves no purpose whatsoever. it's so absurdly over-sensitive that VTEC engagement and gear changes register as "knock" readings.

thankfully, knock feedback is altogether ignored on OBD1 ecus. honda only began to use knock feedback for timing management with obd2 systems. the d16y8 uses realtime knock feedback to alter ignition timing, which is a very different architecture from the OBD0/1 "maps".

i don't recommend what you've suggested, even if it's been fine for 80k+ miles.


as for acceleration:
i have a b16 tranny, so i get to take advantage of shorter gearing to accelerate faster with less throttle input.


also, i'm working on another 40+ mpg tank this week. i may even best my former record fill-up of 43mpg

[theholycow]

Originally Posted by gearheadcheapskate

I'm trying to figure out what it likes best for acceleration- low rpm lugging or a higher-engine-speed with very little throttle opening. Any ideas?

Lugging is bad, but what you're describing is probably not lugging.

http://www.standardshift.com/forum/v...p=91271#p91271

I'm pretty sure that most people who think they have been lugging their engine really have not been lugging it at all. I'm not even sure that modern ECUs and knock sensors would let the engine lug. My experience with the Jetta so far has been that it either runs or stalls. I have not heared it lug (even when I accidentally took a corner in 4th instead of 2nd).

Putting a load on an engine at low RPM will make it growl, but growling is not lugging. Lugging is irregular. If it growls and goes it is not lugging (at least in my understanding of the matter).

http://www.standardshift.com/forum/v...ed7710#p172612

It isn't lugging. You'll never forget the sound of lugging once you do it. Sounds like a bunch of metal sh*t exploding under your hood. Or like a jackhammer.

Based on what I've read there, growling is acceptable, but lugging is very terrible.

So, that all said, it's been my experience that wider throttle + lower RPMs = better FE. My observations are explained by reduced pumping losses -- it's awful difficult to suck air through a closed throttle, but if RPM is low and throttle is open, it can suck easier while still not getting a lot of volume and therefore not using a lot of fuel.

[Torturella]

Originally Posted by theholycow

... it's been my experience that wider throttle + lower RPMs = better FE. My observations are explained by reduced pumping losses -- it's awfully difficult to suck air through a closed throttle, but if RPM is low and throttle is open, it can suck easier while still not getting a lot of volume and therefore not using a lot of fuel.

Are you saying power is lost (gas is wasted) because of the closed throttle? Is it better to "lug" up the hill in 5th than downshift? I guess I have to completely rethink my shifting style. (I have a "new" VX that gets 34 mpg)

[theholycow]

Yes, that's what I'm saying. I can't be 100% sure on the explanation of why it works, but it works for me. It ought to work great for the VX; as I understand, the VX is designed to produce decent torque at low RPM and be driven like that.

[spotaneagle]

gsr that weighs 2450 i thought integ weighed 3k, no wonder hes doing so good on mpg, my new partial air dam(over fog light holes) has reduced air noise on the road significantly, not sure about mpg yet tho, I doubt its hurting any..

and yes recently ive been trying 1800 rpm +/- shifts and its saving me a ton of fuel///