legacycentral bbs

This is only relevant because I'm using an N/A computer, injectors; fuel pump. etc.


I've got my EJ22T plumbed up and all that good stuff, been running it on a wideband for a month or so now, did some fine tuning with that (outputs a 0-1V signal back to the ECU, etc)

Turbo is the stock VF-11 set to wastegate pressure; in 4th or 5th gear this is around 8PSI past 3250 rpms (80-90mph in 5th); pressure is normally at 5PSI and will creep up as load and rpms increase.

I've seen it climb to 10psi all by itself (extended 5th gear pulls, up a hill at higher rpms)


Now the point of my story is this:
Innovate's LC-2 wide band controller, gauge, all that great stuff. during mid throttle input sub 5PSI the ecu tries to run the engine around 13.8-14.2 AFR
if I mash it sub 4000 rpms, 4th gear; AFR's will bounce around for a second, sometimes they hit 16; but every time they'll settle down to 12.5-13.5 AFR;

I know the jumpy AFR's has to do with the injectors going static, but I don't know the exact duty cycle % on the injectors, doubt there's an easy way for me to tell either.

I've estimated the 'dwell time' (duration that the intake valve is open on any one cylinder) at 4000 rpms is approximately 60ms milliseconds; I've seen in the past my injecors run up to 32ms dwell time; but it's been awhile since I was able to record that information. I'm sure they're going static, I just can't tell at what rpm and load range.

The night that I got the turbocharger setup, I took it out and did some runs after letting the computer warm up and adjust. I didn't hit 5 volts on the MAF (but it came relatively close, 4.92 or something); and I didn't see much knock, but the O2 was reading 0.00 volts so I knew it was lean.


anyway, what it boils down to is thusly:
4th gear pulls - 2000 to 4000 rpms, expect AFR's from 12.8 to 14 respectively at 7PSI on the turbocharger
past 4000 RPMS, anything goes; I've seen mine climb to 15 and not felt knock (I can't really hear for it, car is too loud - but I haven't felt the retarding from it since the new O2 sensor, I do know what it feels like)


Same for 5th gear; load is higher, turbo builds more pressure and engine undergoes more stress for longer; again I've not seen anything above 15:1 for more than a split second.

I'm NOT SAYING THAT IS SAFE. Most people who do turbo builds factor in a good margin of error and prefer to run no leaner than 12.5-13:1.

My car has an AWIC (no water in it yet) so there's pressure drop from the turbo to the intake runners; my boost gauge is hooked up to the intake runner however, just down from the brake booster hookup; so what I see on my dial is probably two PSI shorter than what the turbocharger is putting out.
I've also got an open end 3" downpipe, which would explain the boost creep.

again, not saying any of these numbers are safe; but I've not had any engine knock with the new wideband sensor in. tis fantastic and a nice piece of mind, I know clearly when I need to back off even in daily driving - I also use 93 octane religiously which I'm sure has bought me some spare room when it comes to knock avoidance. I wouldn't do this with 87 octane.

my mileage has gone down however, 20.5 last tank, probably around 18-19 this tank but I reset the ECU so it would learn with the new wideband sensor.

food for thought. can't wait for my autronic :\

I would get a rrfpr in there......

douglas vincent wrote:I would get a rrfpr in there......

Not running lean enough to justify wasting the money; no knock occuring. Today I did a 3rd gear pull from 4000 rpm to 5500 rpm on the highway, approx 7PSI in the runners; no knock, wideband was reading 13.5 AFR - shifted into 4th and did the same pull with similar results.

the real solution to lack of fueling is bigger injectors and proper engine controls; not RRFPR's.

I am going to upgrade my fuel pump to a walbro next, there's a good chance that mine isn't delivering enough fuel when the regulator opens the tap up to 40-45PSI.

Knock is hard to hear on Subaru's. More like a faint tick tick tick.

Do you have any idea what EGTs are on yours runs?
High EGTs can kill a motor that has a bad ignition advance map so the wideband does only so much for peace of mind.

The AFR leaning out for a second sounds like a lean spot the car has on boost onset/transition.

Those are about the same AFR's I am seeing on my EJ-22T with the stock turbo ECU, and stock narrowband O2(read by a JAW and Bosch sensor). I was kind of suprised at how lean the engine was being ran by the stock ECU.

Matt

I was always curious what the stock setup runs for afr's.

What is the leanest you see during a WOT pull matt?

Mine seems to run consistenly from 13.2 to 13.6 WOT under different conditions.

Matt