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more info on volvo ecus (yay)

linuxman51 said:
I do not have access to such things, so I couldnt tell you whats on a rex ecu. Hey tell mike thanks again for the ecus and to lemme know what shipping ran (and whats up with these wheel chair feet props or whatever?). With the wideband hooked up on mine it threw a code, but I dont believe it was an o2 code (every time mine threw a code i got all my ignition timing taken away, i think there was something up with the crank pickup sensor). with the wideband hooked up to the ecu the car ran stoich pretty much 24/7, under acceleration the a/fs were closer to 14.2ish, but cruising it would rarely go over 14.8. It was pretty neat to watch, my fuel economy went up about 10 miles per tank (but my lackluster mileage had more to do with the codes the car was throwing elsewhere, and the code reader broke, never bothered to figure out what the problem really was, i just lopped rex off at the knees and installed megasquirt).
It would be interesting to watch lh's fuel curves with the stock narrow band hooked up on an otherwise well tuned car. I suspect on turbo cars it gets nasty rich, esp in higher than stock load levels.

Mike sez he thinks he shipped you the Regina boxes that he was going to give to me by mistake. :rofl: Forgetful.....But helpful....He's definitely helpful.

I was thinking it would be interesting to look at the code since it might be possible to change the increments it advances/retards timing by, as well as possibly change the maximum and minimums for them. Hell, with a little soldering, you could have a toggle switch on your dash that would allow you to switch between programs. Overkill? Maybe, but if I recall correctly, somebody here says that overkill is consistantly more fun. :-D
 
i dunno that i'd expect anything on that level from rex, not without a fair amount of monetary investment (which, when you get right down to it, isnt warranted with the plethra of available and functional aftermarket systems). about the only "skew" that might net you any performance would be a potentiometer on the load signal going to the rex-i box, cars tend to run more advance with lower loads, so adjusting the load signal might get ya a little better zip (or more knock, but eh, who cares about NA knock ;) )

an alternative for the interstate might be to put a slight resistance on the map sensor to fake both systems out, coupled with a signal generator hooked up to the o2 sensor input (whats the point of leaning things out a touch if the computer sees this and compensates eh?). one could also monkey with the ECT and the IAT. do it, and tell us whatcha learn.
 
Metalgod_Z said:
I was thinking it would be interesting to look at the code since it might be possible to change the increments it advances/retards timing by, as well as possibly change the maximum and minimums for them. Hell, with a little soldering, you could have a toggle switch on your dash that would allow you to switch between programs. Overkill? Maybe, but if I recall correctly, somebody here says that overkill is consistantly more fun. :-D

Actually, no. I think the timing precision is a function of the crank trigger. If you go to my image gallery (go up a few posts), I'm pretty sure I scanned in that page. Long story short, the Bosch wheels allows for more precise control (1/8" degree versus 1 degree).

Different programs might be interesting, but I'd say spend the energy hacking up the Bosch stuff instead (b/c it's more common). If you google around, some of the Saab guys already have EPROM dumps from their 2.2 and 2.4 Jetronic ECUs.

--
alex
 
Jetronic editor software here: http://www.mtek.chalmers.se/~burenius/

Rev limit is, in fact, in the ECU.

2.2 and 2.4 brains are said to be significantly different animals (different rev limit locations = one example).

2.4 said to tolerate greater deviance than 2.2; e.g., better able to handle bigger injectors. I've read it can keep closed loop good to ~25% outside normal fueling. Some engines better/worse than others.

Sucking out .bin files with this software might help people tune aftermarket and Megasquirt systems because the editor shows warm-up fueling strategy, cold-start fueling, etc.:

lh-editor2-358.gif
 
blarf said:
The Rex system isn't really anything special. Compared to the Bosch systems, it advances the timing in larger steps (1.0deg v 0.375deg w/ the Bosch systems).

The green manual plays up the Rex system's adaptive abilities, EZ-116K has adaptive abilities as well. The Rex-1 system doesn't make use of an oxygen sensor input (neither do the EZ-K systems). The adaptive bits are interesting, but if I'm reading things correctly it'll take preemptive action, and retard the timing further (by at least 1degree) if it detects a prolonged condition of high load (EZ-116K does this as well).

--
alex

Also the trigger-wheel is differnt , EZK-116 uses 60-2 pattern, and REX is running on 44-2-2, so EZK "knows" which cylinder pair are about to fire. Outside bank (cyl 1 and 4) or inside (cyls. 2 and 3). REX knows only when it is time to fire.

OttoB
 
How long did you drive the Rex car with the WBO2 simulating the NBO2?

I am curious about fuel economy gains? Performance gains? Any other differences?
 
So there is no LH 2.4 NA comp, eh, I am now feeling dumb for picking up a 2.4 ECU to +T my mom's car with. Is there any way to add a LH 2.4 comp onto a LH 2.2 car?, or would I have to pull the dash to get at the hard-to reach wires or something like that.
 
KLowD9x said:
How long did you drive the Rex car with the WBO2 simulating the NBO2?

I am curious about fuel economy gains? Performance gains? Any other differences?


through a couple tanks of gas, no real increase in economy, maybe 10 more miles to a tank (the o2 sensor apparently wasnt bad eh), performance was as ****ty as before.

So there is no LH 2.4 NA comp, eh, I am now feeling dumb for picking up a 2.4 ECU to +T my mom's car with. Is there any way to add a LH 2.4 comp onto a LH 2.2 car?, or would I have to pull the dash to get at the hard-to reach wires or something like that.

2.4 wont even plug into a 2.2 slot (at least not the 2.4 ecu i took appart a little while ago). if its a 2.2 700 series, just swap the ezk and lh boxes from a turbo car in. no need to comp for anything, it just works.
 
linuxman51 said:
through a couple tanks of gas, no real increase in economy, maybe 10 more miles to a tank (the o2 sensor apparently wasnt bad eh), performance was as ****ty as before.

Well how did you have it setup? Was it emulating a zirconia or titania narrowband oxygen sensor?

If it wasn't setup to emulate a titania sensor, or if you pulled a "normal" oxygen sensor, that would explain why it wasn't running well.

--
alex
 
linuxman51 said:
2.4 wont even plug into a 2.2 slot (at least not the 2.4 ecu i took appart a little while ago). if its a 2.2 700 series, just swap the ezk and lh boxes from a turbo car in. no need to comp for anything, it just works.


I know the two plugs don't match up, as I have both ecu boxes sitting with me right now. I was wondering how signifigant the differences in the harness were and how difficult it would be to swap that.
 
acbarnett said:
I know the two plugs don't match up, as I have both ecu boxes sitting with me right now. I was wondering how signifigant the differences in the harness were and how difficult it would be to swap that.

Kenny is right. It's not worth the effort. For the number of differences (not only in the harness) that you have to deal with, it's much cheaper and faster just to get the correct ECU.
 
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