Fuel Injection Upgrade from Carbs

[michaelp]

90+ (Pathfinder/Maxima etc) "PWR-2" Power Transistor Unit has a more modern faster-responding transistor for switching the coil on/off. It fixes any slow response time of the coil....combined with a better coil in itself, your theory of the problem will likely go away, if it even exists. It takes a tiny bit of wiring modification to run the newer PTU, but I've noticed improvements in idle quality and butt-dyno.

 

BTW Tony D....VG guys have and will continue to rev over 6500rpm with the ported turbo-automatic oil pumps and the stock ECU/ignition. Don't know how many times I've said that its happened.

 

BTW, the way Careless solved the oiling issue is the same way I did. VG33...it has a better oil pump. Others run turbo-automatic pumps, ported...and it helps a lot.

Edited May 30, 2012 by michaelp

[NewZed]

I think that the point about the RPM limit is about quality, not quantity.

 

 

For some reason this comes to mind, although the characters don't quite match up. Tis but a scratch...

 

[Gollum]

Point of issue I would take with Gollum's comment about 'improvements': "Computer Controlled GM Carburettors" -- my god, talk about beancounters torturing engineers to hold on to tooling and obsolete ideas! FINALLY it just wouldn't do and they went to real TBI...and not solenoid controlled metering rods. In that case, I'd take the old Quadra-junk over THOSE! Definitely not an improvement!

 

You've certainly found an exception to my philosophy tony, but consider this. All of that complication was done in the pursuit of improvement, mostly (if not all) in the emissions arena. They might have even succeeded in some regard in that area. Just because it was a PITA to work on and made power like an underwater windmill doesn't mean it didn't reach some engineering "goal". I've seen my philosophy ring true time and time again, the more you improve a system, the more complex it will tend to get, and the harder it will be to diagnose.

 

A great analogy to this I think is trying to compare modern GSXR carbs to an old GB TBI V8. Those early EFI systems were in many ways "simpler" than a complex carb, but how many are in junkyards due to EFI related issues that nobody wants to take the time to solve? With a carb you can just run to the autoparts store and buy a crappy edlebrock and get your butt home. It'll cost you sub $300 for a brand new unit in almost any configuration, which is far less than any EFI system unless it's a part out you got a steal on.

 

The GSXR carbs on the other hand are a work of art. Not only did they meat emissions compliance and were only phased out for as much of legal reasons than anything else, but they were also wonderful at making GOBS of power. The newer EFI GSXR doesn't make a ton of extra power the carbs left behind, but they certainly do have their benefits. Repairing GSXR carbs doesn't look like something I'd really be eager to jump on of course, as their beautiful performance does come at a price.

 

The moral of the story is that again, you should get what works for you. If you want to have a car you can race and daily drive, I suggest EFI. If you want something cheap (for an L motor) I suggest OEM EFI. If you want something that looks and sounds amazing, carbs are probably for you. If you're racing competitively, go with what's legal and deal with the limitations as best as you can. If you want a hot street motor but want the look, sound, and simplicity of a carb, go for it. If you want to drive 6,000+ miles cross country, either make sure to check over your carbs before you leave and pack basic tools, or making sure your EFI is in as perfect working order as you can get it and bring as many spare EFI parts you can muster. Or if you have lots of money to blow and want the best of everything, try going ITBs with standalone, which offers sexeh looks, a wonderful sound, and probably the best performance you can get from your intake and fuel system.

[Six_Shooter]

Six Shooter, you are arguing semantics. The ECM's make adjustments on the fly. In layman's terms that is 'self tuning'...

The same sort of subroutine is used in the BOSS EFI to self-tune the ECU. By selecting to save the adjustments, the BOSS system then makes the trims PERMANENT (something the GM unit doesn't do for obvious reasons.)

 

If you take something that is running, and in five minutes of idling things have changed internally the way the ECM sends signals to the injectors and it does this AUTOMATICALLY, I would argue that indeed that would be considered 'self tuning' by 99.99999% of the people out there. I'm not going to split semantics.

 

I'm not arguing semantics, your wording is endowing the ECM with a function it is simply not capable of.

 

The term "Self Tuning" implies that the ECM will make changes and adjustments to say the VE table to adjust how much fuel is injected at a certain load and RPM, and not just trimming, but actually change that value in that cell. This would also imply that the ECM will be able to change it's own calibration, without any human input for other changes, mechanical changes, such as installing larger injectors, or changing the camshaft(s), or installing heads with different flow characteristics, or installing headers, etc. The Delco ECM simply can not self adjust for these. The fuel trim that the Delco ECM does provide are very small changes, and ONLY while in "closed loop." Closed loop being once the O2 sensor is warmed up, and the engine temperature has reached a certain threshold, that the ECM will use the O2 sensor input to adjust fuel delivery. So all that time while the engine is still cool and the O2 sensor is not yet switching, the engine is running off the pre-programmed maps, so if there have been mechanical changes made, the ECM won't be able to attempt to compensate for them at start up.

 

Here is the PW calculation for what is used in the Turbo Sunbird, Syclone, Typhone and some DOHC I4 applications:

 

BPW = BPC * MAPP * T' * A/F' * VE * F33C * BLM * DFCO * DE * CLT * F77

 

Where:

BPW = Base Pulse Width

BPC = Base Pulse Constant Term

MAPP = Manifold Pressure Term

T' = Inverse Temperature Term

A/F' = Inverse Air Fuel Ratio Term

VE = Volumetric Efficiency Term

F33C = Battery Voltage Correction Term

BLM = Block Learn Correction Term

DFCO = Decel Fuel Cutoff Term

DE = Decel Enleanment Term

CLT = Closed Loop Correction Term

F77 = Turbo Boost Multiplier

 

(taken from the "Turbo_P4_doc")

 

As you can see BLM, is only part of the equation, and after the VE table cells have been used in the equation.

 

Other Delco ECMs use similar, if not the same formula for injector PW, or "BPW."

 

Mass Air systems will use LV8 in place of MAPP. Hybrid systems that use both MAP and MAF, will use the MAF for fueling and the MAP for spark timing control, along with using either input for a multitude of other functions.

 

So for an ECM to be "Self Tuning" it would have to actually take the BLM (among other parameters), and change what is in the VE table, not just adjust it farther along in the formula.

 

The BLM (and INT) are not saved as tables either, they are instant values (8-bit value to be technical) that are adjusting the next injection pulse, to get the air fuel ratio to either be stoich, or swing through stoich, as the Delco ECM does, when a proper tune has been established.

 

Also when you move the throttle past a certain threshold, the Delco system goes "open loop", and reverts to the VE MAP as it is, as long as the BLM was at or above 128, then it uses the BLM value of 128 in the BPW formula, if the BLM was below 128 then it uses the value that the BLM was at when entering WOT OL and PE mode.

 

Some Delco systems even use Open Loop idle, or have the option in the programming to do so, so again, the BLM would have no effect on the BPW in this case, negating any learned BPW adjustment.

 

I don't know what this "BOSS" system has to do with the discussion on Delco ECMs "self-tuning," other than trying to dance around the fact that you're using a poor choice of words, or you just simply don't understand how it works and are trying to twist the discussion.

 

Even in "lay-man's terms" what you are saying is incorrect. "Most people" understand that an ECM, especially an OEM ECM can not "self-tune," but they can easily understand that it can make minor adjustments.

 

A correct term or string of words would be "Able to make minor adjustments."

Edited June 1, 2012 by Six_Shooter

[studioti]

1338127679[/url]' post='1001809']

So sad to see a thread about a legitimate topic about someone needing some advice turn into a pissing match. Very disappointing.

 

AGREED 100%

I don't post much. I try to come here and learn. We've all made mistakes and we all grow from it and should share it.

Bottom line...if I start to read a thread and then see "Tony D" posting on it, I tend to stop and move on. I don't care how much he knows or what road he's been down (and driven that). The minutes in my life are worth more than wasting time reading his diatribes.

[NewZed]

I enjoy the battles. Usually learn something new. This thread is really interesting because we've got Nistune and Delco ECUs being discussed, for which I've seen sparse data on the Hybridz site. Sir Arthur, I mean Tony D, usually calls people out when they make absolute statements with no backing evidence. If they can come back with the support, everybody learns something.

 

"Self-tuning" is the latest hot topic in the aftermarket EFI world. MSD, FAST, Mass-Flo and Holley all have "self-tuning" EFI systems from what I've browsed at the local Barnes and Noble. Six-shooter is sharing some good knowledge about what exactly that means for the Delco systems, also in general.

 

It's all good from my seat.

[Six_Shooter]

I enjoy the battles. Usually learn something new. This thread is really interesting because we've got Nistune and Delco ECUs being discussed, for which I've seen sparse data on the Hybridz site. Sir Arthur, I mean Tony D, usually calls people out when they make absolute statements with no backing evidence. If they can come back with the support, everybody learns something.

 

"Self-tuning" is the latest hot topic in the aftermarket EFI world. MSD, FAST, Mass-Flo and Holley all have "self-tuning" EFI systems from what I've browsed at the local Barnes and Noble. Six-shooter is sharing some good knowledge about what exactly that means for the Delco systems, also in general.

 

It's all good from my seat.

 

Yes, there are some systems that do actually have "self" or "auto" tuning (not the T-pain "auto-tuning" lol). The issue is, that the auto-tuning ECMs only have target numbers in tables to go by, these are theorectical tables, that may work for one engine, but not another, which is why I still prefer to tune "manually." I have a friend that decided to install a F.A.S.T. EZ-EFI system on his Nova recently. He's had less than stellar results with it, which I will partly blame on who installed it, since that shop has a very bad track record when it comes to getting things right on the 2nd or even 3rd time a vehicle goes back to them. The results seem to be on par with what I've read across the forums discussing that same system, seems great at first, then realize that it doesn't perform up to expectations.

 

I've seen similar results from people using "VE fixers" and other (usually) Excel based table corrections, where the VE tables get to look more like mountains than a smooth table, and cause driveability issues. The code I use has an Excel based "Auto-Tune" feature, but don't use it, because it's shooting for a theoretical "perfect" number, and sometimes it seems to miss filtering out some of the data, where AE (Accel Enrichment), PE (Power Enrichment), DE (Decel Enleanment) and DFCO (Decel Fuel Cut Off) are skewing the data.

 

There are times when this same issue comes up using an OEM ECM, such as the Delco, when certain parts, like a cam have been swapped to a much larger, and/or longer duration, where the exhaust mixture at idle, will be "rich" in the tail pipe, due to the open valve overlap. If there is no open loop idle, then the ECM will try to lean out the mixture until either the engine stalls, or the ECM decides there is a problem, usually throwing a check engine light, and giving a "rich exhaust" code. This is because the ECM is trying to target a specific number, in the case of the Delco, a BLM of 128, which is equal to the stoich setting in the bin (14.7:1 for gas, OEM BIN files). This is why it's so important to tune a system properly, and when need be, use an open loop idle, along with some other tricks.

I run my car open loop 100% of the time, at first it was just so that I could tune the set-up (tuning in closed loop can be very difficult and cause a tuner to chase their tail on getting it right), then I just left it that way. This way I can also run lean on the highway, I'm usually running between 15.2 and 16.5:1 when in steady state cruise. Another friend of mine that I have been tuning for (1971 Cutlass, with custom 4bbl TBI, and electronic trans) have his set to open loop 100% of the time, mostly due to his very large "non-EFI friendly) camshaft. We also found that stabbing the go pedal from idle or just off idle was better in open loop as well.

Edited May 31, 2012 by Six_Shooter

[Gollum]

In my experience, the only time an "auto tune" feature from the standalone market is useful is if you have either an engine with unknown internals that you need a baseline for, or you have an unusual parts combination engine that you can't accurately guess what it'll flow, then you can baseline with the "auto tune". If it's just getting a base map going they can really speed things along, but I'd NEVER EVER EVER consider it a "forget bringing it to a tuner" feature. It WILL leave power on the table in most cases and will more certainly NOT run stellar under the curve.

[Careless]

Learn from our mistakes, don't repeat them. You can beat your head into the wall trying to get that to work, and the inversion of the coil trigger gating simply makes for a fail. The 930 Turbo Coil is (as far as I know, and you will notice it on all the NNA Factory Racers with VG's...) the 'fastest' rise time out there. But even Bosch has limits...

 

 

Ok. Forget what I have going on with my engine for a second, and if you could- please answer the simple question.

What needs to be done- aside from buying the 930 Turbo coil and putting eyelet terminals on the wires and mounting it somewhere in my engine bay- in order to run the coil on my Z31 ignition system.

 

You made mention of the coil- and how Nissan Motorsports was suggesting the use of the coil, but that it's a waste of time anyways.

But that still means the information is out there and someone knows what's required to put it in the mix.

 

Basically what I'm asking is not whether it's possible... I'm asking if you know how to make the coil work with the Z31 ignition, or not?

I've seen the coil in the pics of that 700hp vg33 with the black roof, i can't remember who owns it at this point. He works for Nissan Motorsports too apparently.

 

I'm not saying you're lying or that it's not true. The coil is in plain sight. But what was done to make it work. Do you know? and can you detail that for us.

 

Reason I ask is because I can get that coil for about 60 bucks. And I am not going to swap to a COP setup any time soon. So I'd like to know what's involved in at least improving the ignition system for the time being. 60 bucks is not a lot if all I have to do is wire it up. Heck, I even have a connector that I can just use to make it plug and play if it doesn't work.

[Tony D]

PM Sent-I will not discuss this publicly for obvious reasons.

[HowlerMonkey]

The pre-obdII GM systems were advanced for thier time but were made with inferior construction and the conformal coatings sprayed on those ecu boards that leached under the chips is now swelling and pushing them right off the board.

 

I can't even count how many GM ecus I've been sent at my rebuild facility that actually had chips rattling around the box because they got pushed clean off the board.

 

The worst of the bunch is the "9278" ecus for the early LT1s. If you have one that is malfunctioning, then your ecu is in it's natural state.

 

Many of the OBDII GM ecus are identical hardware between 6 or 8 cylinder engines and the tune decides which hardware is operational.

 

Sure the LT1 ecus enjoy an almost identical signalling for crank/cam reference and the optical disc inside the duraspark "distributor" have a very similar waveform as the nissan V8 ecus, but the reliability of that ecu is very bad.

 

Look familiar?

 

 

 

 

If you're going to try GM or Jeep ecus, go with the OBDII ecus so you can easily tune them through the scan tool connector but remember that the later you go, the higher possibility that you will run into "immobilizer" or "security" issues.

 

The jeep 4.0 ecus around year 2000 are amazing and can handle much any curveball you can throw at them but the voltage regulators inside them don't handle having Vref shorted to ground well and will cook the regulator.

 

I probably replaced 600 of those regulators over the years..........and then had to support the customer who sends it back with the regulator burnt again because he can't grasp the cause and effect relationship of his damaged ecu.

 

For an L28 with another brand ecu, the most difficult part is satisfying that ecu's need for crank reference.

Edited July 28, 2012 by HowlerMonkey