Fuel Injection Upgrade from Carbs

[Six_Shooter]

Given the choice between carbs (any), '70s EFI, and more modern EFI (including '80s technology), I'd take the more modern EFI, for driving performance, ability to be tuned easily, with more points of adjustment to have the least amount compromise, ability to be serviced easily and more adaptable to different applications.

 

That being said I do love the sound of engines with one carb barrel per cylinder, or mechanical stack type injection, but prefer the ease of use and service of modern EFI.

[NewZed]

I deal with tuning modern EFI every day, but at the same time...

 

To get back on track, with some facts, how about some examples? You've said the above several times, but you're running SUs on your Z and have one grainy video to show. I, personally, would like to know more about using a Z31 EFI setup with Nistune. The write-ups around the Z forums are fairly vague and never go in to much detail, besides matching wire colors. How about an example of a Nistune tuned Z31? How about describing that 250 whp turbo 86 in your sig? That would be something worth hearing about.

 

You could share some knowledge with Buffalo_Z about tuning SUs and tuning with Nistune. He even asked about upgrading to a later model EFI system in his first post.

[19762802+2]

I made 145hp and 150ft/lbs on a p79/F54 L28 combo on a junkyard motor with unknown miles, all stock except for a MSA header, 2 inch exhaust, Thrush Welded muffler (exhaust done myself) and some early 3 screw Round top SU's with a shitty tune and if I remember right it was running rich on the top end that day. I also live at 6500ft with a stock 4 speed and a 3.36 rear end so if IIRC you lose 3% of power with every 1000ft of altitude above sea level, at Sea level I should have made around 170hp. I'm going to see if I can get the new owner of my car to send me a Copy of the Dyno sheets I had.

 

Here is a dyno video to hold you guy's over till I get the sheet scanned.

 

 

Forgot to add I was running 26 degree's total timing with a E12-80 dizzy and a ZX alternator swap.

Edited May 27, 2012 by 19762802+2

[Tony D]

Thank you 762802+2 for injecting truth into the mix: SU's are not some great panacea where you pick up gobs of horsepower unless your stock EFI is severely malfunctioning.

It's a wash, at best. Reinforcing the contention all along that claiming the stock EFI 'Sucks at making Power' is just one of those myths perpetuated on the internet by people unwilling to take the time to learn about it, or who have never had a stock system that was working as it did when even somewhat new.

 

The same logic for discarding SU's for Mikuinis can be said as well. Because you make Xhp with this system doesn't mean your SU's "Sucked at Making Power"--yet this is the argument.

Whaddya do with that?

 

Frankly, the same logic goes for the Z31 system as well. In comparison to modern GM EFI with long and short term fuel trim, and the ability to SELF-TUNE to each individual engine, it functions so much better you could say "The Z31 system sucks for making power, and is unuseable above 6500 for serious turbo applications due to insufficient coil charge time the way it controls it."--but this crowd would shorten it to "It sucks for power."

 

If you're going to say something sucks for whatever reason, at least come up with valid reasons and not hype or "I changed it to this along with this this and this, and got this..." It's not a real apples to apples comparison. I suppose I could change my 2+2 back to carbs and run another dyno check. I think my stock EFI is performing decently. I just basically bolted it on from a box of parts someone gave me after they took it off after 176,000 trouble-free miles when they turned the car into a racer, and put latest-technology EFI on to it. But out of the box, it made 147 and pushed the car to 15.50 all day long. To me, as stated that is far from "Sucking for making Power"---especially reinforced by the disturbed gent in San Antonio who was 1 full second slower than me all night, with his big-throat TB, Header, Mandrel Exhaust, CAI with Cone Filter, and shiny paint. How do I explain it? I don't know, maybe the guy was an idiot. I wasn't the fastest that night, nor was I the slowest. But I did appreciate running 26 passes consistently, not to mention the Auto X, driving to the convention from SoCal, and then on a tour around the USA putting 18,000 miles on the car in about three weeks time. Summer heat, across the entire desert southwest towing an 800# trailer in heat above 110F in some cases...never slowed for an instant. No only doesn't that reflect well on the stock EFI, IMO, it reflects well that the car being 30+ years old at the time driving all that way without a hitch means those Datsun Engineers knew what they were doing and did something right.

 

Before I dismiss their work with an off-the-cuff "Their system Sucks" I think back about that drive, and many others and say "Maybe Not, with my new SU's, I had to slow down below 85 in the Baker Grade when it was only 85 outside..."

[Six_Shooter]

Can I have the GM Service Number and BCC of this self tuning GM ECM?

[michaelp]

"The Z31 system sucks for making power, and is unuseable above 6500 for serious turbo applications due to insufficient coil charge time the way it controls it.

 

Still not sure where you got this incorrect theory of the Z31 EFI being unusable above 6500rpm.

 

To get back on track, with some facts, how about some examples? You've said the above several times, but you're running SUs on your Z and have one grainy video to show. I, personally, would like to know more about using a Z31 EFI setup with Nistune. The write-ups around the Z forums are fairly vague and never go in to much detail, besides matching wire colors. How about an example of a Nistune tuned Z31? How about describing that 250 whp turbo 86 in your sig? That would be something worth hearing about.

 

You could share some knowledge with Buffalo_Z about tuning SUs and tuning with Nistune. He even asked about upgrading to a later model EFI system in his first post.

 

My 250whp run @ 10psi was with a bone stock 9:1 VG30E, with the turbo exhaust manifolds and 260cc injectors, a FMIC, ASCO plenum spacer and 3" turbo-back exhaust. The ECU is a Nistune'd 86NA ECU with a slightly modified '87 EDM (European Domestic Market) tune, I just threw in a bit more spark advance at lower RPM. Its a really conservative tune atm, runs about 9.5:1 AFRs in boost...but that is stock Z31 fuel maps. Rev limiter is set at 6600rpm, which is the stock euro-Z31 rev limit (HMMM..thats higher than 6500). I have 450cc injectors in it now and am putting my t3/t4 on shortly, working on getting a basic street tune down. It starts and runs with no issues though. But yeah, stock Z31 turbo ECU/tune can handle ~250whp.

 

In the past, I've built a VG33ET 84 Z31, not quite completely gutted it weighed about ~2700lbs. I ran a custom tune on it with the stock injectors and 9psi of boost on the stock T3, never dyno'd it....I revved it to 7,000rpm, rev limiter was set to 7200. DAMN, wheres that not being able to rev over 6500?

 

I'm running SUs on my 280Z because they were cheaper than going with Z31 EFI and Nistune to tune it or stand alone, and they are capable of flowing more air than any of the stock L intake manifolds. One of these days I may get around to building a custom EFI intake manifold for the L28 and running Z31 EFI or stand alone...but until then, carbs is a better solution for me.

 

BTW. Tony D, modern EFI can learn to correct within certain limits, but it can't self-learn for different sized injectors or make the injectors magically support more power than they do. They're still running off pre-programmed fuel maps and timing maps, and only adjust mildly.

 

Anyways, enough with the bickering. Most of this was just a stupid misunderstanding...and its all a matter of opinion. All setups can work great, just depends on what you want.

Edited May 28, 2012 by michaelp

[NewZed]

If I understand your reply right, you're saying that a stock VG30E with a stock Nissan turbo setup, will produce 250RWHP using a European Domestic market ECU, an FMIC, 3" exhaust and plenum spacer? Just plug the European ECU in and bolt the parts on? The low RPM timing advance increase won't have any effect on max RWHP.

 

Trying to understand where the tuning is to create the horsepower. It looks like you plugged in a Euro spec. ECU and adjusted low RPM timing and added some mechanical parts. Wikipedia says that the Euro 300Zx made 247 HP (SAE crankshaft calculation I assume) due to a Euro spec. camshaft, and the domestic turbo made 200. Is it the 3" exhaust, FMIC and plenum spacer? With stock domestic camshaft?

 

From the Wiki -

"This new V6 (2960 cc) Single overhead cam engine was available as a naturally aspirated VG30E or a turbocharged VG30ET producing 160 hp (119 kW) and 200 hp (150 kW) respectively."

 

"European models

 

The European models made 241 hp (180 kW) [13] in turbo form due to a better camshaft profile, also known outside of Europe as the Nismo camshafts."

 

Just trying to see what's what. Details trump all...

[michaelp]

If I understand your reply right, you're saying that a stock VG30E with a stock Nissan turbo setup, will produce 250RWHP using a European Domestic market ECU, an FMIC, 3" exhaust and plenum spacer? Just plug the European ECU in and bolt the parts on? The low RPM timing advance increase won't have any effect on max RWHP.

 

Trying to understand where the tuning is to create the horsepower. It looks like you plugged in a Euro spec. ECU and adjusted low RPM timing and added some mechanical parts. Wikipedia says that the Euro 300Zx made 247 HP (SAE crankshaft calculation I assume) due to a Euro spec. camshaft, and the domestic turbo made 200. Is it the 3" exhaust, FMIC and plenum spacer? With stock domestic camshaft?

 

From the Wiki -

"This new V6 (2960 cc) Single overhead cam engine was available as a naturally aspirated VG30E or a turbocharged VG30ET producing 160 hp (119 kW) and 200 hp (150 kW) respectively."

 

"European models

 

The European models made 241 hp (180 kW) [13] in turbo form due to a better camshaft profile, also known outside of Europe as the Nismo camshafts."

 

Just trying to see what's what. Details trump all...

 

I'm running Nistune with a stockish euro tune...this car hadn't been tuned much except some ignition timing stuff until I put the 450ccs in the other day.

 

The power is MOSTLY from a MBC set at 10psi, instead of the stock 6.8psi. A full turbo-back exhaust has been proven to add ~20-30whp too over a stock exhaust (cat-back only is about 10whp, but the downpipe is stupid restrictive)...then the FMIC is mainly to support more boost. The plenum spacer mostly moves where the engine makes power than adding to it. I make peak horsepower at ~4900-5000rpm, versus stocks ~5200rpm...

 

I never said THIS specific Z31 was tuned. It was on a mostly stock tune when I made 250whp, which is why its AFRs were stupid rich. I tuned others in the past, both my own car and other peoples. I havent been to the dyno since putting the 450cc injectors in....waiting until I get the bigger turbo in.

 

A stock VG30ET will make ~250whp with a cheap MBC set @ 10psi, FMIC, full exhaust and a K&N cone filter. Its been done multiple times, if not 250whp...damn close...but usually on dynojets, so being mustangs generally read lower I assume the timing adjustments and fuel map difference in the euro-spec tune helped it out. I'm also running stock NA base timing of 20°BTDC, versus the turbos 10-15 (depending on year)

 

 

The dip in power around ~3k is from the crappy stock turbo tune going stupid rich as soon as "high" boost (more than stock) hits.

 

Anyways, like I said...I tuned my old VG33 car with stock injectors, 9psi of boost, no FMIC, and a full 3" turbo-back exhaust....its powerband felt much smoother afterwords with AFRs around 10.5:1-11:1 (still MILDLY too rich) and it was definitely quicker than this one...

Edited May 28, 2012 by michaelp

[NewZed]

I asked about tuning and that's what you replied with so I assumed it was a tuning example. I'm seeing an increase in boost, manually, and an intercooler to allow it without detonation, but still not seeing any EFI programming.

 

Not clear on why the AFRs would be rich on a stock tune, just because of a boost increase and an intercooler. Is it going in to "limp home" mode when it sees MAPs outside of factory limits?

 

Plus, wouldn't this situation be the point of a "tunable" EFI system, and a good opportunity to use it. Why did you live with the "mildly rich" AFRs if Nistune is tunable and you were tuning?

 

I'm just not seeing any use of what the Z31 system with Nistune is supposed to offer. These examples are like the guys that use the RRFPRs to run a turbo on a stock NA ECU. It works but crudely. Where is the fine control to produce a clean running, powerful engine with modern car qualities, like good power with a smooth clean idle and good gas mileage to top it off, that EFI tuning should give? It's just a manual boost increase and a bigger exhaust system. I really don't see anything here that's much better than the old analog EFI system. Seems like a Nistune system could do better.

[michaelp]

I asked about tuning and that's what you replied with so I assumed it was a tuning example. I'm seeing an increase in boost, manually, and an intercooler to allow it without detonation, but still not seeing any EFI programming.

 

Not clear on why the AFRs would be rich on a stock tune, just because of a boost increase and an intercooler. Is it going in to "limp home" mode when it sees MAPs outside of factory limits?

 

Plus, wouldn't this situation be the point of a "tunable" EFI system, and a good opportunity to use it. Why did you live with the "mildly rich" AFRs if Nistune is tunable and you were tuning?

 

I'm just not seeing any use of what the Z31 system with Nistune is supposed to offer. These examples are like the guys that use the RRFPRs to run a turbo on a stock NA ECU. It works but crudely. Where is the fine control to produce a clean running, powerful engine with modern car qualities, like good power with a smooth clean idle and good gas mileage to top it off, that EFI tuning should give? It's just a manual boost increase and a bigger exhaust system. I really don't see anything here that's much better than the old analog EFI system. Seems like a Nistune system could do better.

 

 

It varies on the ECU, because you're limited to the table size of whatever ECU your Nistune is running on (Z31s are 16bit, tables are 16x16 tables...one cell per RPM/load range). You can fine tune the injector pulse width in each RPM/load range cell. I just opted for keeping the stockish tune for now since I had plans of going with bigger injectors anyways, no reason to do the job twice. Like I said, on my VG33 car...I adjusted the cells to run around ~11:1 AFRs in boost at every load range I was operating in by making multiple pulls and datalogging.....the car ran much better than it did with the stock tune and definitely gained power, but I never dyno'd it. The fact that the Z31 ECU is digital and has actual programming and fuel maps/timing maps, etc, that you can TWEAK every cell on to precisely tune it for a smooth idle and proper AFRs at every load range and RPM make it worlds better than the old analog EFI.

 

This guy was running a Nistune'd Z31 ECU:

 

 

And no, it wasnt going into a limp mode...Nissan just tuned the load it was running in stupid rich to be safe. BTW, I averaged 31mpg on a 300-mile highway trip with my VG33 car.

Edited May 28, 2012 by michaelp

[Gollum]

You both crack me up. You're both from completely different worlds and see things very differently, yet you both truly see the value of EFI over carbs.

 

Unfortunately michaelp, you have obviously had some BAD history with the bosch systems and haven't spent the hours upon hours reading up on them. Do they have limitations? Yes. But so does EVERY OEM EFI yet guys commonly make 50% or more than stock power without flashing. Is a fully programmable EFI or even a custom ROM better than "making a stock tune work"? Hell yes. But let's not have some fantasy about how carbs work perfectly.

 

I like carbs for the fact they're damn straight forward to repair and a million times less likely to leave you stranded if you're Macgyver enough. By a simply philosophical standpoint the better you make something the more complicated it will become. There are some very simplistic carb designs out there that are easy to work with and fairly idiot proof, but they also have many more limitations than the better carbs on the market. In the same light, early EFI is simple and elegant in many ways, lacking the required feedback levels modern EFI boxes do. As systems evolve, it seems they become more and more temperamental, requiring more and more thought into the designs to make them "warranty proof". Notice how a modern sensors tend to be double if not triple the price from just 20 years ago? That's not just part dealer markups.

 

In the end you need to find a system that works for YOU. Carbs have their place, as well does modern Motec, Electromotive, MS, etc.. And for a good many people, there's nothing "wrong" with the datsun EFI. Turbo guys have made well over 300whp with it, and though I'm sure they left power on the table somewhere, they got it done and spent far less than many other options. I've seen people make quite a bit of power in the NA realm with the stock ECU. And in all honestly, I find the stock EFI just as, if not more, tuneable than SU's in some ways. But I also have a folder full of information I've gathered over the years of all sorts of neat tricks on tuning the EFI. By modern standards people would consider it "workarounds" but then again a carb is a workaround by design.

 

And all that said, I'm ditching the stock EFI in my '75 L28ET S30. Why? Because my particular stuff is just DONE. My AFM is junk, I have a pile of CTS's that vary in spec as much as the daily stock market, my harness needs to be completely redone, all the parts are just plain wore out. They've been abused over the years, make no mistake, but I'm just ready for something else at this point. I have no delusions about the stock system though, it's good for what it is and I don't hate it. I just want to move towards something that's easier to work with FOR ME and don't want to deal with sourcing old used datsun parts. I want to buy NEW parts that are easy to find over the counter, available everywhere, and not overpriced for what they are. Oh, and did I mention NEW? When was the last time anyone here bought a TRULY new AFM? And how much did it cost?

 

Oh, and one more thing michaelp, though Tony D can be a total arse, he has more hands on experience than most of us here, and you might be surprised by how many "modern" efi systems he's had his hands on.

 

Regarding the Z31 6500rpm thing, never once did I see tony say it wouldn't rev over that. He's talking about the ECU's ability to control dwell. That doesn't mean it won't rev up there, just means it's hard to get optimum spark energy and timing up there. The Z31 is far from the only ECU with these limitations. There's ways to get around it, but it's usually an inherent issue with the ignition drivers. This is also why MS1 and MS2 guys will run a heat sink on the case in many cases if they're running all their drivers and turning high RPM. Once you've been at high RPM long enough you'll start getting spark scatter and spark blow out. Keep the drivers cooler, and voila, problem solved. Or you run a low current driver arrangement to LS1 coils and call it done.

Edited May 29, 2012 by Gollum

[Tony D]

Can I have the GM Service Number and BCC of this self tuning GM ECM?

 

Any of the LT1 V-8's. I had to learn about it when the Father-in-Law couldn't get decent service, and then my Buddy put a 94 LT from a Camaro into his 74. From there I learned the Tunercat Package.

 

Basically the 94 LT ECU has both short-term and long-term fuel curves that use switching from the O2 Sensors as a method to make adjustments to the programmed base fuel map. This is what is 'reset' when you disconnect the battery cable. It's not just GM stuff that does it, they ALL do it now because of the 100K emissions requirement. They HAVE to self-adjust or they will fall out of compliance with EPA requirements for long-term emissions compliance. The stuff on the mid 90's Nissan stuff does it I'm sure. I just knew the GM does it, and with Tunercat it's so easy to turn things on and off, toggle this or that, reprogram the slushbox shiftpoints.

 

Anyway, it's not the SErvice Number, BCC but it is an example of the Year, Model, and Engine Family which should allow you to check into it. Get TunerCat at the same time, it's an OBD Interface connection, it was really intuitive. Running a V8 I don't know why I'd use a Standalone if using a GM Product---the GM ECM has all the capabilities you really need when using the TunerCat tool and your laptop. It's got OEM reliability/durability. Something not found with aftermarket systems. In fact, the BOSS EFI systems being sold for the past few years use this same GM-Style Short and Long Term Fuel Trim as a 'save option' after driving the car to change the base map---sold as 'self tuning' it really truly is! Aftermarket following the lead of the OEM's... This is the same thing the EEC332 EFI system did, and really when you look into the Megasquirt they relied heavily on GM programming. GM was hacked long ago... Their programming really is straightforward, when you see the subroutines, you realize most of the programming and changes between boxes are due to emissions requirements. With the Long and Short Term fuel trim, there are fewer base maps, and the things tweak themselves for best drivability. Pretty neat bit of engineering.

 

I see there is other drivel posted... I guess the piss mark isn't high enough on the fencepost yet. Wanna make a bet he didn't READ a goddamned thing and is just going off on the same broken record yet again???.

 

 

 

[Tony D]

"Still not sure where you got this incorrect theory of the Z31 EFI being unusable above 6500rpm"

 

Try to make turbo power with one at 7200 and show me your dyno sheet. At 6350, the coil switching changes, and the dwell goes to hell. It's why all the guys running the Z31 Box make their HP at 5800-6300 and why they ALL have that divot in their power curves at that time. The box inverts the signal to the coil at that point. Unless you use a Turbo 930 Coil with a super-fast rise time, the scheme simply doesn't allow proper coil charging of a SINGLE coil to power cars under high boost.

 

That's why. Been there, DISCARDED THAT! Moved on to the Z32 COP system. FAR better than that Z31 POS Junk! Don't waste your time... Especially if you want a 7500 or 8000 rpm Turbo Screamer. (738RWHP / 7200RPM@16psi where the turbo just plain ran out of air... That's on the Area 51 Mustang Dyno down off Bake St. in Irvine, BTW... Couldn't get close to that on the Z31 Box. The Z32 Box? Sky's the limit! Tested to 8K and other pressures... Photos on the engine dyno previously posted at this site...) Actually, the Z32 system was stable up to 11,000 CAS rpms... But what do I know, right?

 

And I was correct, putting words in the mouth that never were said. Wonder WHY the box has an OEM limit at 6600? THINK about this, will you PUHLEAAAASAE?????? Yeah, I can rev a stock engine to 7500+ as well. Doesn't mean it does anything. Believe what you will, I know the truth of the Z31 Box. So does JeffP. You don't EVEN want to get him into this thread regarding the time wasted using the Z31 Box when looking for serious horsepower! No, don't EVEN get him started! That dyno video looks like most of the others I see---where was that power peak again??? Pretty close to where Steve Mitchell's was... Same point where ALL the turbo Z31's make their peak. Hmmmm, wonder WHY?

Edited May 29, 2012 by Tony D

[Tony D]

I want to Thank Gollum, for once again READING what I've written and taking it in the manner which it was put forth.

 

I'm not the one pissing on a fence to build up a ridiculous statement.

 

I'm just the one showing respect due to the Engineers who spend thousands of hours making each of these systems work when new. Some people (including me) appreciate the pains OEM guys (and by that, I mean the factory engineers) take to get these systems to do what they do straight off the lot, for hundreds of thousands of miles. Been there, done that.

 

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!

[michaelp]

"Still not sure where you got this incorrect theory of the Z31 EFI being unusable above 6500rpm"

 

Try to make turbo power with one at 7200 and show me your dyno sheet. At 6350, the coil switching changes, and the dwell goes to hell. It's why all the guys running the Z31 Box make their HP at 5800-6300 and why they ALL have that divot in their power curves at that time. The box inverts the signal to the coil at that point. Unless you use a Turbo 930 Coil with a super-fast rise time, the scheme simply doesn't allow proper coil charging of a SINGLE coil to power cars under high boost.

 

That's why. Been there, DISCARDED THAT! Moved on to the Z32 COP system. FAR better than that Z31 POS Junk! Don't waste your time... Especially if you want a 7500 or 8000 rpm Turbo Screamer. (738RWHP / 7200RPM@16psi where the turbo just plain ran out of air... That's on the Area 51 Mustang Dyno down off Bake St. in Irvine, BTW... Couldn't get close to that on the Z31 Box. The Z32 Box? Sky's the limit! Tested to 8K and other pressures... Photos on the engine dyno previously posted at this site...) Actually, the Z32 system was stable up to 11,000 CAS rpms... But what do I know, right?

 

And I was correct, putting words in the mouth that never were said. Wonder WHY the box has an OEM limit at 6600? THINK about this, will you PUHLEAAAASAE?????? Yeah, I can rev a stock engine to 7500+ as well. Doesn't mean it does anything. Believe what you will, I know the truth of the Z31 Box. So does JeffP. You don't EVEN want to get him into this thread regarding the time wasted using the Z31 Box when looking for serious horsepower! No, don't EVEN get him started! That dyno video looks like most of the others I see---where was that power peak again??? Pretty close to where Steve Mitchell's was... Same point where ALL the turbo Z31's make their peak. Hmmmm, wonder WHY?

 

Theres soooo much false info here about Z31s...ignorance. People don't rev over 6500rpm because the VG30E(T)s stock oiling system is eh. The stock oil pumps can't move enough volume to support revving over ~7,000rpm....if you do, with a lot of power, you spin bearings from lack of oiling. It has NOTHING to do with spark control....but since you're clueless about Z31 stuff and just keep pulling crap out of your ass to try to make yourself feel happy about that crappy analog EFI you have....

 

Gee, why was the OEM ECU rev-limited to 6600rpm? Maybe because they made peak horsepower at 5200rpm (or 5400rpm in euro form)? They drop off in power around 6k, theres no reason to rev higher...THAT is why they are limited. Why is a VQ35 rev-limited to 6500rpm? etc....more stupid statements from Tony D.

[michaelp]

I want to Thank Gollum, for once again READING what I've written and taking it in the manner which it was put forth.

 

I'm not the one pissing on a fence to build up a ridiculous statement.

 

I'm just the one showing respect due to the Engineers who spend thousands of hours making each of these systems work when new. Some people (including me) appreciate the pains OEM guys (and by that, I mean the factory engineers) take to get these systems to do what they do straight off the lot, for hundreds of thousands of miles. Been there, done that.

 

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!

 

Yeah....respect the engineers who spend thousands of hours making these systems work. Like when they spend all of that time developing the DIGITAL ECCS setup used on Z31s, and everything newer from Nissan is based off this...that proved to be 10,000 times better than the analog crap they used before. Yet, you sit here praising the analog EFI as if its the best thing ever. You constantly insult other options, and go on with spreading FALSE information about other stuff....stand alone, Z31 EFI, whatever it be, all you've done is talk about how horrible it is and how EVERYONE should keep the stock 280Z EFI. So please, take your own advice and show the respect due to the engineers who developed the better, newer, stuff.

 

Regardless, Gollum basically said what I said a few posts ago. Its a pointless argument, we all have our opinions of what works best for what we want. So I'm leaving it here. Someone asked me questions about Nistune, so I offered them help with understanding it....those posts were nothing towards Tony D or anyone else.

 

BTW. Obviously coil on plug is better for spark...doesn't mean the z31s distributor setup isnt capable. There are still FAST cars with distributors....and being the Z31 doesnt use points and has electronically controlled ignition, its fine for what it is.

Edited May 29, 2012 by michaelp

[Careless]

Try to make turbo power with one at 7200 and show me your dyno sheet. At 6350, the coil switching changes, and the dwell goes to hell. It's why all the guys running the Z31 Box make their HP at 5800-6300 and why they ALL have that divot in their power curves at that time. The box inverts the signal to the coil at that point. Unless you use a Turbo 930 Coil with a super-fast rise time, the scheme simply doesn't allow proper coil charging of a SINGLE coil to power cars under high boost.

 

I admire your technical knowledge, but rather than pin-point the Z31's faults and offer obscure solutions- the Z31 crowd can benefit from your help in fitting these 930 coils to the Z31 ignition system.

You can hem and haw all you want about how much the Z31 EFI sucks, but you seem to be implying that the coil is the only reason the ignition system sucks. So either post the schematics or provide some sort of technical data on how well the system responds to this modification and/or how to go about it.

 

This EFI sucks.

That EFI sucks.

But if you do something like this, it won't suck.

So how do I do something like this? (Turbo 930 Coil).

 

 

If you don't know the answer then how did you come to the conclusion, or who can we consult to fix the issue?

 

I'd sure as hell like to know because I have a 60mm turbo on my 9:1 VG33ET now, and the roller lifter/rocker setup that is in development would surely allow me to go well beyond the limitation that you have outlined with the Z31 EFI system.

[Six_Shooter]

Any of the LT1 V-8's. I had to learn about it when the Father-in-Law couldn't get decent service, and then my Buddy put a 94 LT from a Camaro into his 74. From there I learned the Tunercat Package.

 

Basically the 94 LT ECU has both short-term and long-term fuel curves that use switching from the O2 Sensors as a method to make adjustments to the programmed base fuel map. This is what is 'reset' when you disconnect the battery cable. It's not just GM stuff that does it, they ALL do it now because of the 100K emissions requirement. They HAVE to self-adjust or they will fall out of compliance with EPA requirements for long-term emissions compliance. The stuff on the mid 90's Nissan stuff does it I'm sure. I just knew the GM does it, and with Tunercat it's so easy to turn things on and off, toggle this or that, reprogram the slushbox shiftpoints.

 

Anyway, it's not the SErvice Number, BCC but it is an example of the Year, Model, and Engine Family which should allow you to check into it. Get TunerCat at the same time, it's an OBD Interface connection, it was really intuitive. Running a V8 I don't know why I'd use a Standalone if using a GM Product---the GM ECM has all the capabilities you really need when using the TunerCat tool and your laptop. It's got OEM reliability/durability. Something not found with aftermarket systems. In fact, the BOSS EFI systems being sold for the past few years use this same GM-Style Short and Long Term Fuel Trim as a 'save option' after driving the car to change the base map---sold as 'self tuning' it really truly is! Aftermarket following the lead of the OEM's... This is the same thing the EEC332 EFI system did, and really when you look into the Megasquirt they relied heavily on GM programming. GM was hacked long ago... Their programming really is straightforward, when you see the subroutines, you realize most of the programming and changes between boxes are due to emissions requirements. With the Long and Short Term fuel trim, there are fewer base maps, and the things tweak themselves for best drivability. Pretty neat bit of engineering.

 

I see there is other drivel posted... I guess the piss mark isn't high enough on the fencepost yet. Wanna make a bet he didn't READ a goddamned thing and is just going off on the same broken record yet again???.

 

LT1 PCMs are NOT "self tuning."

 

The long term and short term adjustments are just simple fuel trims, based on O2 feedback, called BLM (Block Learn Memory, "long" term) and INT (Integrator, short term). INT adjustments are pretty much instant and finer than the BLM, BLM, adjusts once the INT hits a certain threshold for a length of time, and is much corser of an adjustment.

 

LT1 PCMS are NOT "self tuning."

 

All Delco ECMs have used the fuel trims based on O2 feedback from the early '80s, if it has an O2 sensor, it uses the same fuel trim algorithm , but is not "self tuning." It is "self adjusting," or better yet "Self-Trimming."

 

"Self Tuning" would be making adjustments directly to the fuel tables, adjusting the numbers in the "VE table" or MAF counts tables, not just making trims. This would be self programming of the PROM or flash memory, which none of the OEM Delco ECM/PCMs do.

 

The "long term" adjustments really are quite short, these are relative terms, meaning that the INT adjustment is shorter in time (almost instantly) to adjust than the BLM ("long term"), which can change every few seconds.

 

The O2 feedback of the Delco systems is simply a fuel trim that is added or subtracted from the injector pulse width calculation, this is not the same as "self tuning." This is meant for adjustments where fuel grade might change, altitude changes, air temp changes (where an IAT or MAT sensor doesn't change the PW enough), environment (some areas will be higher in un-burned fuels than others, I've watched a buddies rich running car that was in front of me effect the way my engine ran, also shown by the O2 sensor feedback), EGR contribution and anythng else that might effect the air fuel ratio, that would require trimming or adding fuel in an instantaneous or almost instantaneous manner.

 

We haven't even gotten into the Spark Advance (SA) tables yet, where the O2 has no effect on, since there are no trims in the same manner as the O2 feedback, but there is a knock sensor that will retard timing based on engine harmonics, that the sensor and knock filter report as "knock."

 

BTW, I'm quite familiar with Delco ECMs, and how they function. I have an OBD1 GM ECM running my Turbo L28, using DIS with a code that did not originally use it, I mention that because it required changing some parameters in the bin file itself to have proper timing relative to the crank, which is different than what a dizzy ignition needs, due to the way GM designed differently in the DIS ignitions. I have been running this for about 4 years on my own car. I've tuned and helped tune many other GM vehicles, that use a multitude of different service numbers and codes, in both originally equipped vehicles and most commonly conversions.

[Tony D]

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.

 

As for the other issue regarding Z31 boxes:

The L-Engine DOES NOT have a shite oiling system. So putting a Z31 box onto it will REVEAL the DEFECT in the Z31 box that inverts the coil signal. There is (or was) EXTENSIVE DOCUMENTATION on this issue at JeffP's website. We spent a HELLUVA lot of time trying to get that pig to have silk ears, and that pig just don't hunt, son.

 

It doesn't reveal itself on the VG because the oiling is so crappy. Sorry you guys got a bum oiling system.

 

But DIDN'T THIS ALL START when someone ignorantly suggested putting a Z31 Box onto an L-Engine?

 

BEEN THERE DONE THAT, FOUND THE SHORTCOMING AND EVEN WITH THE 930 COIL THE BOX CAN'T CHARGE THE COIL FAST ENOUGH FOR CONSISTENT SPARK OVER A GIVEN RPM POINT UNDER BOOST. We (JeffP and I) went so far as to make an environmental chamber and test bench in his garage to simulate under-boost pressures to check for spark blowout.

 

Z31 Box on Turbo-L Series=FAIL

 

Like someone said earlier: End of discussion. If you're going to apply something that won't do the job to the capabilities of the engine block it's on---why bother with it?

 

If you want a Turbo Z with an L-Series and want to REV IT LIKE AN L-SERIES IS KNOWN TO REV, don't waste the time on the Z31 Box-you will be sorely disapointed. Go STRAIGHT to the Z32 Box and COP system. It's good far as our test chamber and bench without fail to 22,000 engine rpms. Works for me.

 

This ALWAYS happens with Z31 guys, nobody can say ANYTHING about the car no matter HOW factual without it becoming some sort of penile-threatening statement that draws out people calling anybody disagreeing with their love of all things Z31 "Stupid" or "Ass Talkers" or what have you... Man grow UP!

 

I'm done with it. I know what I know, I know what we tried, I know what Cunningham Racing told us, I know what the National Service Manager at Nissan North America said, I know what our dyno results showed consistently over TWO YEARS of trying to make that goddamn box work, and I know what the brain trust at Nissan Motorsports finally said when we quizzed them about it and what we had found. If you guys can't handle the shortfalls of your system that's your issue to handle.

 

You want drawings and prints? Jeff went so far as to have the boards for the Z31 box reverse-engineered in a vain attempt to figure out something in the circuitry that maybe could be altered to make it work... I doubt he will part with them, but that's how far we dug down this rathole of a box to find out in the end it just don't work. Get your ego and investment out of it, and READ my conditions and caveats. PLEASE.

Edited May 30, 2012 by Tony D

[Tony D]

And Careless, seriously, if you have the ability to go into the 7K region and are going to look for power (having somehow solved the oiling issue---I'm thinking dry sump) don't waste your time with the Z31 box, you won't fix it. Go get the Z32 CAS, convert what you have, go COP and don't look back.

 

Someone once said you can't make a silk purse out of a sow's ear. This is just one of those cases.

 

For a high boost cast-piston motor that won't go over 6500 you can make gobs of power with the Z31 box. Some people want more than that will produce. If you go beyond that point, bin it--don't waste the time, effort, or money.

 

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...

 

I will say this: 25psi of boost on ports flowing 218CFM with a cam that idles with 5" Hg vacuum, and the ability to run those revs up and shift at 8K+ on a street car is something that you will not quickly forget!

 

As for 'the Z31 Crowd Benefitting'---all they had to do was call Nissan Motorsports when they were in Gardena. The were quite forthwith about the 930 Coil and supplied us with the part number as 'the coil to use if you are going to try to operate at higher rpms with that trigger scheme'!

 

At the same time, in the same face-to-face discussion at the NNA Motorsports Offices, we were also told the Z31 Coil was the hottest one Nissan Ever Made up to that time. So that I what I run on my L28 cast-piston Turbo Engine.

Edited May 30, 2012 by Tony D