I know the norm around here seems to be upgrading to larger injectors for boost. What is everyone using to control them, s-afc, other? Has anyone noticed this to be as issue as its not boost controlled, but rather rpm controlled?
12.6 @ 114.6 MPH
There is a big ass faq at the top of this page.
What your going to here though is hptuners this and that. So there you go
Matt, I would convert over to a 97 PCM, and run the 97 speed density tune I uploaded to the HPTuners repository. I would then fake a 2 bar map sensor and tune using that. Maybe in conjunction with a rising rate fuel pressure regulator.......
Or convert over to a 00-02 computer / harness / BCM, and gauges and run the GM Supercharger tune, and tune from their. Since the GM charger tune can see boost naively in the stock tune to 14.7 psi.
Edited 1 time(s). Last edited Wednesday, March 09, 2011 10:59 AM
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Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
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-MD- Enforcer wrote:Matt, I would convert over to a 97 PCM, and run the 97 speed density tune I uploaded to the HPTuners repository. I would then fake a 2 bar map sensor and tune using that. Maybe in conjunction with a rising rate fuel pressure regulator.......
Or convert over to a 00-02 computer / harness / BCM, and gauges and run the GM Supercharger tune, and tune from their. Since the GM charger tune can see boost naively in the stock tune to 14.7 psi.
Thanks, but I'm just asking in general. I'm boosting another vertical of mine, not a j-bod. On my cav, I have larger injectors and s-afc. But that general management was from years back and I'm sure guys have come up with better solutions now which I'd like to try an incorporate to the other ride I'm boosting. It will be low boost (5psi) on a 4.0L, but the pain in the ass part is that its a returnless fuel system, so a simple fmu is out of the question. I could throw an s-afc on there as well, but I worry about when it boosts at lower than normal rpm. I'm thinking a boost driven system would be better, but I know most guys on here get by just fine with the larger injectors, so that's why I ask what they are using to control them and how its working out.
12.6 @ 114.6 MPH
Here's an idea. If you're gonna be messing with something other than a J, don't you think that at the very least, you should specify what it is that you are working on???
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Most of us use HPtuners and adjust the injector constant for the bigger injectors.
yea.. how's that s-afc working on the jbody (that is fueled via alpha-n)?
learn to tune.
DaFlyinSkwirl (Pj) v2.0 wrote:yea.. how's that s-afc working on the jbody (that is fueled via alpha-n)?
learn to tune.
rotfl.
Seriously, use the googlesphere. I'm sure EFI Live, cobb, ez flash, rom raider, or something else supports that car. If not looks like a stand alone is your only real option. piggy backs like the safc are just bandaids and really do suck horribly.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Ohh i know. I never liked the idea of s-afc since its only rev based, but back when I started using it on my cav's setup, thats really all there was for fuel management for jbods. There was seriously just about nothing as far as big performance parts go for us then. Its amazing how far this area has advanced since then. I'll check into those other ideas for my current project on the dodge.
12.6 @ 114.6 MPH
--Glowin Cavy-- wrote:Ohh i know. I never liked the idea of s-afc since its only rev based, but back when I started using it on my cav's setup, thats really all there was for fuel management for jbods. There was seriously just about nothing as far as big performance parts go for us then. Its amazing how far this area has advanced since then. I'll check into those other ideas for my current project on the dodge.
the s-afc interfaces through the map sensor correct?
are you measuring your AFRs or are you goin by your butt dyno? because the MAP sensor on the jbody has NOTHING TO DO with how much fuel is used.
alpha-n = RPM and TPS references for fuel, end of story.
the only time the Jbody PCM uses the MAP sensor for fueling is during idle, and coastdown, so either you're full of BS, inexperienced, or both.
DaFlyinSkwirl (Pj) v2.0 wrote:--Glowin Cavy-- wrote:Ohh i know. I never liked the idea of s-afc since its only rev based, but back when I started using it on my cav's setup, thats really all there was for fuel management for jbods. There was seriously just about nothing as far as big performance parts go for us then. Its amazing how far this area has advanced since then. I'll check into those other ideas for my current project on the dodge.
the s-afc interfaces through the map sensor correct?
are you measuring your AFRs or are you goin by your butt dyno? because the MAP sensor on the jbody has NOTHING TO DO with how much fuel is used.
alpha-n = RPM and TPS references for fuel, end of story.
the only time the Jbody PCM uses the MAP sensor for fueling is during idle, and coastdown, so either you're full of BS, inexperienced, or both.
Well technically if he sized his injectors right and just pulled fuel with the safc for idle and coast down he could be almost kind of semi ok.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Keep in mind this post was for boosting another car, but back to my cav... it was initially boosted about 8 years ago, and not touched for the last 6, hence why the fuel management isn't the best. Injectors were upgraded to 42lb. The s-afc pulled back some of the pulse width dependent on the RPM. A wideband kept an eye on the a/f. Although not the best method of fuel management, back then it was either that or an FMU, that was it. It actually worked great too. It was only ever boosted up to 8lbs, but was able to easily keep a steady 13:1-13.5:1 under boost and closer to 14.5:1 around idle if memory serves correct.
12.6 @ 114.6 MPH
DaFlyinSkwirl (Pj) v2.0 wrote:--Glowin Cavy-- wrote:Ohh i know. I never liked the idea of s-afc since its only rev based, but back when I started using it on my cav's setup, thats really all there was for fuel management for jbods. There was seriously just about nothing as far as big performance parts go for us then. Its amazing how far this area has advanced since then. I'll check into those other ideas for my current project on the dodge.
the s-afc interfaces through the map sensor correct?
are you measuring your AFRs or are you goin by your butt dyno? because the MAP sensor on the jbody has NOTHING TO DO with how much fuel is used.
alpha-n = RPM and TPS references for fuel, end of story.
the only time the Jbody PCM uses the MAP sensor for fueling is during idle, and coastdown, so either you're full of BS, inexperienced, or both.
I'm not really trying to argue but we know the 95 ecu is speed density and that some 97s have a speed density setup. His profile says he has a 96 which to my knowledge no one has really gotten into as far as programing. I don't think its too crazy to think that the 96 could be a speed density system. Which could be why he has had success with the setup.
