New computers

mrvette

Phantom of the Opera
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Thread elsewhere got me thinking, some comments about how much better newer computers are at engine controlls, and ease of programming, so forth, so the question is.....since the engine is finally running well, and gets about 24.7 mpg with my 336 rear and 200 4r auto, it's a 355 with LT1 induction on a L98 engine, intake al welded up and modified.....

just what could a more modern computer with another O2 sensor bring to the table??? and what reall life affect/improvements could I expect for the efforts to get one in there??
 
Man, if you're getting damn near 25 mpg in one of our antique aerodynamic bricks, I'd say you've wrung most of the inefficiency out of it. I would think the cost/benefit ratio for further improvements would tend to be on the expensive side.

JMO (I'm thrilled when I get 18 mpg.)
 
With wideband you could go lean in the higher vacuum regions of your fuel table and still programm it for performance elsewhere. You could go to let's say 16-17/1 AFR in that region. You have to consider the fact that your engine runs in this region when at cruise, so most of the time.

How many mpg this would save you is difficult to say.

Anyway, you would certainly need a wideband O2 sensor and a programmable EFI computer.
 
With wideband you could go lean in the higher vacuum regions of your fuel table and still programm it for performance elsewhere. You could go to let's say 16-17/1 AFR in that region. You have to consider the fact that your engine runs in this region when at cruise, so most of the time.

How many mpg this would save you is difficult to say.

Anyway, you would certainly need a wideband O2 sensor and a programmable EFI computer.


AND so we down to the rubb....going throug this BS for a questionable result....is it worth the MONEY and T/Effort???

anyone with a really great input on before/after??? and I see TT's first reply and methinks he been around this horn before enough to know the helm....

others???


:bonkers:
 
What Pier Paolo says is true but for the investment made it will take a seriosuly long time before you even break even, and 24,7mpg...damn, you have a light foot! for us metric guys, that's about 10,5km/1L
 
What Pier Paolo says is true but for the investment made it will take a seriosuly long time before you even break even, and 24,7mpg...damn, you have a light foot! for us metric guys, that's about 10,5km/1L

eh, at 60-80mph, i'ts a fairly quick foot, but I was passing through famous speed trap territory....and so had some small traffic through country hick town too....

dunno what it would do on the freeways, steady on....

do wonder about a cam change to something milder like a ZZ4 cam something...I had an offer of one that was not used, torn out of a crate engine....but lost track of it...damnit....

but it would probably need reprogramming to get it to run again....lovely...

wish there was a way to get a wide band O2 sensor and teach this stock system to run at 17-1 something like that....

:bonkers::idea:
 
Gene, you must be talken about the thread I responded to over at CF. My opinions were trying to point out that if someone today was going to start from scratch and upgrade to EFI, I would not opt for the older GM ECU's. In your case you already have one installed and running with no apparent need or want to modify your engine in the future. My 2001 Tahoe is in that category. :amused: From the sound of things it is running great for you and you are happy. I wouldn't change now. The 7727 /7730 ECU's are EPROM based and cannot be programed real time while running unless you purchase an Emulator and a prom programmer. To me that's a royal PITA. Batman was trying to explain that one could modify the ECU's adding switchable memory, emulation capability etc. etc. I don't know about others, but my time is too valuable to me to screw around updating old electronics technology when its half life is less than 1 year.:suicide: Hell we don't even use EPROM programmers today in my line of work. My point was by the time one buys all the additional capability needed to upgrade the old ECM's to equaling whats available today in aftermarket It just isn't worth it. IMHO.

BTW, how did you get your ECU calibrated to your engine? And, who the hell is Pier Paolo?? I'm a hard headed German/ Scotsman. :bounce:

Bullshark
 
EFI isn't emissions or mpg alone, it's as much or even more about performance and throttle response. BTW : I did it because I want to go ITB's and they are a pain with webers or the sort.
 
BTW, how did you get your ECU calibrated to your engine? And, who the hell is Pier Paolo?? I'm a hard headed German/ Scotsman. :bounce:

Bullshark

PCM for less, Alvin Anderson did the chip in there now....thing is, I think it never was a chip related thing, I was having that really crappy intermittant idle for the longest time, I"d try one thing then another, had problems with a VERY insidious couple of spark plug wires against the headers I get them WET even and would not show any sparking, no blue glow at night, but I finally got it fixed with 8 Jacobs ceramic plug boots and wires all RTVd in place for water controll, then the suggestion from over at DC from several guys to use containers of Techron in the tanks full of gas....well it took about a tank and a half for the thing to even out, that was a LOT of time but it seems MUCH more stable now....the thing idles smooth, runs fine, pulls well, but it allways seemed to RUN ok, just that raggedy 1/2 assed idle was driving me crazy car had more shakes then a belly dancer, freeking mirrors were blurry.....but it's good NOW.....about 4-5 times per tank since the techron went through it, the engine will STILL take a fit to bad idle, but still not as bad as what it was.....not nearly....

SO, I was just wondering how the newer vettes with the LS engines managed to get 30 mpg, and I figgered it was the computer controlls, rather than anything inherent in the engine itself....

Like I said above, wish I could go wide band and teach the computer to look for 17-1 and get near 30 that way...another 10% anyway....putting it to ~27 mpg.....

:stirpot:
 
BTW, how did you get your ECU calibrated to your engine? And, who the hell is Pier Paolo?? I'm a hard headed German/ Scotsman. :bounce:

Bullshark

Oops, my bad. Stroker-427 = Pier Paolo but he didn't reply here. It was 69427 :footmouth:
 
EFI isn't emissions or mpg alone, it's as much or even more about performance and throttle response.


I couldn't agree more..:thumbs: I still have debates with guys who swear that you get more power with carburetors. :stirpot: Since I started my EFI education a few years back, I have had the opportunity to become friends with a couple of brothers who own Competition Marine up here in St.Louis. They are big in offshore racing boats. It is impressive what EFI can do to enhance an engines performance.
Gene, I heard some of your comments on 17:1 A/F and that scares me. Too lean for my blood.

Bullshark
 
I couldn't agree more..:thumbs: I still have debates with guys who swear that you get more power with carburetors. :stirpot: Since I started my EFI education a few years back, I have had the opportunity to become friends with a couple of brothers who own Competition Marine up here in St.Louis. They are big in offshore racing boats. It is impressive what EFI can do to enhance an engines performance.
Gene, I heard some of your comments on 17:1 A/F and that scares me. Too lean for my blood.

Bullshark

Wasn't so very long ago I would have agreed about those lean mixes....but posts by Norval there toward the end, where he played with a LM1 wideband O2 sensor and his results of running 17-1 at light throttle cruise, and at other light throttle applications, while dumping 12-1 or something at heavy load, racing.....it made me wonder how these computers are not really tuned for economy, but to keep the EPA happy, their customers are the EPA on this NOT US.....so it leaves us to do our own work on that....

but so the questions revolve arund that LM1, and how to teach the computer to go lean whenever it can, and hell with that EPA crap.....

and you correct, to watch the figgers on it....BUT, I truly wonder about these O2 sensors we have....how wide they really are in response?? can they read a 12-1 through 17-1 ratio?? or is it the computers have corrected the signals to the injectors by then and so back to 14.7-1??? even IF the one's we have now are not linear in those regions, are they at least reliable?? 200 bux/wide band sensor, PLUS all the messing around with computers to use it, then repeating my frustrations with computer .commmmmm problems and so forth, makes it all not worth it....

:bomb::thumbs:
 
A narrow band will not read to 12 or 17/1. Normally the factory tune is pretty close to 14.7/1 and is only able to correct minor differences.

OK, so you saying the sensor itself is useless in a wide band application, it's not the computer, it's the sensor...ok....what is the affect of pluging in a wide band sensor to a factory stockish computer??? Like I have a heated O2 in my header collector....so to change to a heated wide band and plug it in....what to expect in the operation.....normal??

if so, it would be just getting the chip recaled to recognize the wider signals,and to tell it to go leaner whenever possible....untill knock sensor tells it to richen up a tad....NO???

leave the timing curves alone...NO??


:fishing::fishing:
 
OK, so you saying the sensor itself is useless in a wide band application, it's not the computer, it's the sensor...ok....what is the affect of pluging in a wide band sensor to a factory stockish computer??? Like I have a heated O2 in my header collector....so to change to a heated wide band and plug it in....what to expect in the operation.....normal??

if so, it would be just getting the chip recaled to recognize the wider signals,and to tell it to go leaner whenever possible....untill knock sensor tells it to richen up a tad....NO???

leave the timing curves alone...NO??


:fishing::fishing:


Gene, You can't just plug in a UEGO (wide band O2) sensor into the old ECU's . They are not compatible and cannot be re-calibrated to recognize UEGO. This is another benefit of the aftermarket ECUs, they have the circuitry built in or are at least compatible with an external module. With these older GM ECU's you would have to use something like the LM-1 and data log A/F vs RPM. Then correlate these readings to the fuel map values to set them within the adjustment range of the narrow band HEGO O2 sensor. The LM-1, LC-1 and the FAST A/F systems could then be set to operate in the narrow band mode so they would be directly compatible with the old GM systems and get some closed loop control. Not nearly as good as UEGO though.

Another point of clarification, The knock sensor provides input to the ECU which then controls timing retard. It does not modify the fuel trim.

:beer:
Bullshark
 
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Bullshark is correct on this Gene. There is no way you can make a stock ECU run with a wideband.

When I got my system up and running maybe I could give you more information, but right now it's just a studyproject of mine.

Anyway with oil going towards the 200$ mark, any additional mpg could be well worth it...:cry:
 
Another reason to consider EFI is reliability. Immediate starting in any weather or temperature, etc.

The big mpg factor for new Vettes is a lot of power so you can pull a high overdrive gear. I can get around 25-30mpg too because with an overdrive tranny, the engine is just loafing at highway speeds.

A wideband can easily measure 10-18 a/f.
 
Another reason to consider EFI is reliability. Immediate starting in any weather or temperature, etc.

The big mpg factor for new Vettes is a lot of power so you can pull a high overdrive gear. I can get around 25-30mpg too because with an overdrive tranny, the engine is just loafing at highway speeds.

A wideband can easily measure 10-18 a/f.

Well this engine is supposedly doing 425 ft lbs, so with a 200 4r auto and 336 rear, I suspect I could go to something much milder...like a 308 rear, because I can so easily spin the tires most of the time, so that is quite adequate for street driving....

would dropping 10% off my rpm add 10% on economy??? probably not...

but I can't help think of when I did the very first TPI on my L48 with mild cam and the OEM muncie in there....the car went from 12-14 on freeway to 24 on freeway.....about doubled...and that Qjet appeared to be running well as it could too....

Some guys say it would have to be too rich, obviously, but it never showed any symptoms of that....go figger....

:clobbered:
 
Well, 10% would be noticeable...

Most accurate tests by the most skilled mechanics show not much difference between carb & EFI on either power and mileage. However, carbs go out of tune much more often. Therefore, most folks with carbs are driving them around in an out-of-tune state. That's why EFI is much better overall. With a computer controlling the tune (and able to change as parts wear) you really don't need to do anything except change plugs every 10 years or so... ;)
 
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