I experimented a bit last night by zeroing out MIVEC alternating load columns in the cruise cells and couldn't detect a difference in drivability. I searched on EvoM and found some discussion but no obvious indication that anyone has really tried to figure it out. Wondering if anyone else has experimented with MIVEC in the cruise cells, especially for those running non-stock cams.

I'd have posted in the MIVEC tuning thread, but its rather huge now and not so easy to follow.

 

I've been interested in this for my own selfish reasons. Being in CA, I've considered a track map and a smog/valet map both being 91 octane.

 

I would love to experiment with this with yall but unfortunately my car is in pieces. I drive 24 highway miles each day to and from work. But with my tune i get about 12mpg. When i get it all back together this spring i'll join in or use your data to play with mine.

I will be running piper race cams and the ef4 turbo 9.5/1 compression and e85 when its done. None of which scream fuel economy

 

Theory wise, what creates a slower burn? Induce some exhaust reversion for us egr deleted folk ?

 

Interesting comment on EGR. It prompted me to do a bit of reading on EGR vs mileage. EGR seems to make a lot of sense for improving mileage and decreasing combustion temps. Almost makes me wish I had not blocked off my EGR passage. Maybe I'll unblock it next time I have the exhaust manifold off. Anyhow, I've got a pressure sensor hooked up to my exhaust manifold, so once I get the car back on the road, I plan to log EM pressure during cruise to see what's happening. This may provide some insight on when it would be possible to cause reversion-induced EGR.

 

Mrfred what sensor are you using? I have the jdm mani with m14 plugs for sas.. Also can stft be a good indicator if you make an adjustment then flash and log immediately?

use the baro adc if you're on sd. Or do you use a dlp?

I know my exhaust ports draw a vacuum at idle and I'm not particularly sure where they start seeing pressure

 

We did some EGR testing in an already fuel efficient motor and saw zero gains. The best results for the Evo were to run on the lean side (15.5-16.0, no leaner), run 44-46* of timing, and I ran the MIVEC full advance in cruise to mimic the K series. I was getting 24mpg on gasoline driving on I5 north for 152 miles (hilly terrain) at 75mph with the IX 5 speed. That was my 2.4 and R2 with Magnus for reference.

 

I've got a pressure sensor hooked up to the front O2 ADC. Actually I've got a couple of pressure sensors what I switch amont the front O2 ADC and log various things depending on what I want to look at.

Having MIVEC at full advance should minimize pumping losses and produce a fair amount of internal EGR. 44 deg of ign timing is impressive. My guess is that this much timing only works for really lean burn combined with the full MIVEC advance to get the EGR and even slower burn.

 

well aaron... next time i ask you to hook up my tune with a economy cruise tune... i'll be looking for those numbers...

this is good info. I almost txt you today Mrfred... anything ever come of the fuel pump harnesses with spoolin up? sorry to get off topic

 

Harness is coming soon-ish. Matt@spoolinup was pretty busy for a while but he's putting time into it now to source premium parts.

 

Is the stft a good indicator of immediate changes? Would be looking for the removal of fuel in my eyes..

 

Not immediately obvious that stft is an indicator.

 

odometer states that I have been getting 24 mpg on last two fill ups. 6-speed, GSC S2 and stock turbo. I figure it could probably get better with a larger turbo and possibly a new O2 (AFRs seem to track a from 14.6-15.0 while cruising).

 

What is your cruise mivec map looking like?

 

I have wanted to tinker with the idea of a larger EGR port just to see if any economy gains can even be had. Not much larger, maybe a 20% larger orifice. The factory EGR hole is maybe 3/16" at most.

This would only be using the inert EGR gases as a volumetric filler and not for any emissions purposes at all.

-Jamie