Tony D
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Posts posted by Tony D
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Hmmmm, my reply disappeared...
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Others elsewhere are quoting me on this as well:
http://www.zcar.com/forum/10-70-83-tech-discussion-forum/285058-more-boost-3.html
http://www.zcar.com/forum/10-70-83-tech-discussion-forum/316753-normal-part-hiss-4.html
Last page is where the quote is, maybe earlier there is this discussion in it's full length on what is on a turbo manifold and what it does...
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work on his
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I'm suprised Todd said that. They were specifically addressed in technical literature and stocked as aftermarket parts in Northridge!
Yes, your return line from the regulator should bypass the fuel through those bodies under the carbs, and back to the tank. It is a small orifice, if you have a monster pump you may have to 'sidestream' them.
Only other think I could think of since it's after overhaul is you have a gasket leaking and running lean causing running hot.
I found using the cooling bodies and running a 160F thermostat GREATLY reduced the temperatures under the hood and made the fuel much less prone to vaporize or boil in the float bowls.
My webers would do this off the highway into city traffic...no remedy for that! Which is why I sold them and kept my mikunis!
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"Ill need to go over those lines it appears to make sure that "third" steel line is not clogged or some how got shunted closed."
Spock agrees, this is the only logical course of action.
As I have posted before, a Geo Metro Evap Cannister uses second generation activated charcoal, and is MUCH smaller. It can be housed outside the engine bay, or even in the back by the differential. There is nothing that says WHERE these components have to be mounted. MAKE SURE YOU GET THE RIGHT HOSE BARBS IN THE TANK ACCORDING TO WHERE THEY NEED TO GO!
Chances are good spooge has blocked something. It is fairly common. This wouldn't be the first tank to come off for cleaning to come back with plugged off vent lines from pooled or accumulated sealant! Most good shops run a brazing rod through each nipple in the tank to make sure they are free, and so do I when I get one back! Burned by that on at least three occasions!
FYI, the Geo Metro I chose due to comparable tank storage and EVAP capacity. I prefer mounting the canister in the back, out of sight, and love that I have more room up front (and a second large-bore line front-to-back to use as I see fit!
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If you are going to recirc your BOV, it should recirc back into your intake, as in pre-turbo.
Any reason you are saying this, other than that is what you read somewhere?
Any reason you name to alter it from the stock engineered location?
If you are going to tell someone how it 'should' be done, you should at least give a logical reason.
Now that I've laid out why you have to be careful with that position, why it's an oversimplification, and what the stock valve was engineered to do... Can you give a reason to eliminate the stock Vacuum Control Valve in lieu of the single-function "BOV"?
I have seen engineered systems that get several stock VCV/Check Valve/BOV's and put them in multiple cylinders. The action remains silent and seamless, and you don't get the oil consumption or HC Spikes from the engine as you do with an externally vented bypass valve. What is the solution to the original problem the Nissan Engineers addressed with their placement of the valve. You abandon their solution, yet the problem still exists, now without something to address it.
With the advent of the new BOV's on the VW Turbo Cars being available for around $35 new, the prospect of electronic bypasses and dumps to the manifold concurrently happening off a GPO from an aftermarket ECU (or maybe PCM Control) will soon make these Pneumatic Relics of the past just that: Nostalgic Trash that did what it could the best it could, with the technology available at the time.
The future is electrical operated valves, not pneumatic valves.
Best start learning PID programming now. Or simply claim "what I got 'works' fine!"
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"Turbo: $250
And that's being GENEROUS. You can find a million turbos in that price range that will work just as well, if not better, than the stock T3..."
SHHHHHHH! I got a milk crate of the stockers I have to unload! Don't tell them about the Chinese GT30's out there!
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Just be advised the pittfalls removing the factory unit in lieu of something that functions quite differently and should be sized accordingly. "Dumping it back pre turbo" is a gross oversimplification of what the valve should do when vented that way!
The stock unit does it's job seamlessly and silently. As a properly engineered valve should do. The only real way to properly install what most people have nowadays and what should be properly termed "Compressor Bypass Valve" is about the only thing Mr. Corky Bell and I agree upon. BEGI made a great compressor bypass valve (AKA Today "BOV") and Corky's explanation of it's function in 'Maximum Boost' is about the only redeeming quality in the entire text! And that is what a pre-throttle plate valve is for, compressor bypass and overboost control on drop-throttle. Some turbos now have ELECTRIC ones built into the turbo casing. What about "proper venting" in that case?
There IS a better term, it's just through ignorance and popular vernacular, it's been perverted into a basic explanation and oversimplification of what it actually should be designed to do.
It's why the Nissanspeak term is "Vacuum Control Valve" -- they found the spiking in the manifold and oil consumption/increased HC Emissions were more important, so this is how they managed to tackle both the issue of drop-throttle surge prevention and compressor speed decrease (blow off function) and preventing the manifold vacuum spike until the pneumatic control system could enact anti-stall and additional air to the engine by opening the AAC.
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a thought occurred:
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The alternative has been posted several times by me, find it, I'm not writing all that again.
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Liked JC reiterates, and I originally said:
"That's because you plugged the EVAP line and didn't give expanding / contracting fuel any place to go. If your factory EVAP canister is in place, the diverter valve on the top handles venting and contracting gases from the fuel tank go some place automatically."
Pretty self-explanatory.
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PERCOLATION!
Make sure your timing is CORRECT and that the pulley isn't giving you odd wrong timing readings.
In every case I've seen with Mikuni's percolating, the cooling bodies added to them stops the problem.
Gurgling you hear is fuel boiling in the float bowls. The EFI gas we have is susceptible to this, when at atmospheric pressure.
Running the return fuel through the cooling bodies stops this positively.
The shielding and wrapping will help some, but cooling the carb body is what you need. Short of a 1 gallon ice-filled cool-can made from 20' of copper tubing and a Coleman Cooler (don't even ASK, man!) that's about the best solution you will find.
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while spooning the
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That's because you plugged the EVAP line and didn't give expanding / contracting fuel any place to go. If your factory EVAP canister is in place, the diverter valve on the top handles venting and contracting gases from the fuel tank go some place automatically. If the conversion is done properly, nothing to worry about. Bodge job it and you can run your tank into high vacuum, run low on fuel, and be stranded dead at the roadside until you manually break the vacuum when the cap is opened.
Of course, expanding fuel pushing out into a large puddle on the floor with someone smoking nearby insures healthy insurance payouts for someone's immolated car and house.
You have insurance, right?
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sheep, wearing lipstick
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Fuel pump check valve. Repair kit available on ebay from vendor Toolman's World.
Installs at the back and keeps pressure on the rail.
Second, make sure your FPR is working. Even with the engine off, as the fuel heats, the FPR bleeds off till it flashes to vapor, then the vapor vents off.
A fuel prime solves it, as long as you know your fuel prime is getting FUEL into the rail and at the proper pressure. MAKE SURE the Cold Start valve is OFF when cranking---number one issue with extended cranking is CSV dumping excess fuel...
Stating "it runs too well to think of the common things" is a dumb statement to make. I make my living on people with that attitude, and they show no lack of ire and vitriol when I come in, start at square one, go to the end of the book checking the basics, and afterwards can not repeat their problem.
Best dispose of that notion immediately, or you will be in this issue for a LONG LONG LONG TIME!
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Like I mentioned previously, the SIMPLEST and likely most versatile controller would be to read a differential pressure across the turbo, and chart the point where surge occurs. This seemed to be fairly reliable predictor as as it approached the crossover point, you could predict surge. It happened at Natural Surge, and at throttled surge. The number on the square root output from the DP sensor was almost identical at a 13 bar natural event as at a 10% IGV control point running around 4.5 bar.
It seemed to distill all the variables into a control point that seemed a consistent output regardless of pressure or flow. But you had to surge it once to find that point, then after that tune your system up to respond appropriately. In the industrial setting, they just open the dump valve and vent... Keeping pressure going downstream as constant as possible.
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Example: steam turbine drives...
As refineries (always refineries...) reach surge problems or capacity (flow problems), their engineers ALWAYS call asking if its permissible to up turbine speeds "to get more air"?
As an OEM Tech Services Engineer, the answer I have to give is "no, there is interior aerodynamic parts that have worn and must be attended to..."
They never listen.... Six years later, they call. Over the years, as the machine encountered surging, they simply increase the turbine speed, and it goes away. But as pressure in the plant drops, they get to a point, eventually, that the turbine is now tripping on over speed, the machine can't make design pressure, and surges if an operator sneezes.
Then you go and replace the parts and amazingly it works again. And you show natural surge points: 1000kpa at 2970 input speed, 1100 Kia at 2980, 1200kpa at 2990, 1300kpa at 3000... Each step in input speed changed wheel speed 14X or 10X, depending on pinion attachment. So 140rpm change resulted in 100kpa change in natural surge point. Suction (throttled) surge point mirrored the change. These two points mirror upper and lower points on the surge line, hey give you that surge line slope.
Trust me, that surge line they give you is variable by compression ratio. And it does the same thing with speed as it does with ambient temperature, moves that surge point (fixing pressure) left or right along the horizontal axis. Operate lower on the vertical axis, your two points on the horizontal axis generally become further apart...
There are literally six-day seminars you can attend on the PID Control schemes to combat surge.
Current technology in FIXED SPEED centrifugal compressors is to use calculated poly tropic head to determine the surge point and keep it away from it. For industrial stuff, you want to run as low as you can, tight (within 1%) of the surge line at any given point. This is or electrical costs.
For us, we want to only impart enough excess flow to keep within 1% of targeted maximum boost possible for that control point to maximise torque and horsepower.
Simply put, if you simplify the control, you don't achieve that goal.
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Look at the maps, the surge point moves with rpm drastically. It does NOT "only relate to efficiency"!
"We discount the effect of ambient temperature for the purposes of further discussion..."
IF you hold speed constant, then pressure and flow are the surge variables.
IF you hold pressure constant, then speed and flow are the surge variables.
IF you hold flow constant, then speed and pressure are the surge variables.
This is basic centrifugal theory. The greatest contributors are flow and pressure, speed variation of as little as 5% wheel speed can change surge pressure 1bar.
This unfortunately is a complex subject which automotive manufacturers try to oversimplify. By complexitizing it just a smidgen, the anti surge, and plenum pressure control you get is worlds apart better!
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"I have reached my limit of liked posts for the day" -- but I like yours, too LanceVance!
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Muahahahahahaha "and out in he container of dreams we found..."
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Some of us pull that strut bar before we warm it up!
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Ray,Its no wonder Tony has an aneurism when he reads these posts.
-BOV do not recirc into the manifold. The stock manifold has something to that effect, but its different as the stock L28et did not have a BOV. It uses a check valve at the #5 runner to bleed excess pressure off, but a BOV works a little different. You should be doing a lot of research on how to run a BOV before you proceed, or at least search for pictures of how some folks do it. You may be headed towards disaster if you continue down this path your on. But its your time and money.
The stock BOV dumps into #4 / 5 intake runner area and works well without increased volume of piping associated with an inter cooler (if at elevated pressures.) it's function, as well as how it functions has been covered previously ad nauseam by yours truly. I believe the Nissanspeak for that valve was "vacuum control valve" and it's off-boost dumping into the plenum (like the BCDD) prevents massive spiking of vacuum in the plenum causing oil consumption issues and uncombistible air deprived conditions lowering HC spiking to the catalyst. Removing it, like removing the BCDD has shown increased oil consumption when driven similarly on vehicles I've tested.
Including the 1973 Maroon Roadster with the 82ZXT engine in it that has showed at the last few MSA events...which you can check, Ray...the AFM is mounted EXACTLY where I say, and there is NO harness extension required. Both Ian and I considered this a no-brainier due to the ease of repositioning. Apparently there are incidences of brain deprivation exceeding our wildest expectations as that is where I see a majority of them mounted.
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You realise the stock 75 Ignition in the 280Z is an HEI already, right?
Ready to blow my brains out
in Nissan L6 Forum
Posted · Edited by Tony D
Just because a lot of people do it, doesn't make it right from a technical standpoint. Why succumb to the ricer "they're all dooin' it" mentality. Try to put some thought into it, enrich your mind as to the function of your vehicle and its subsystems. Enrich yourself. Why settle for "he did Tim so I will too"?
As was stated, this ain't Automotive 101. If you post idiotic crap, expect to be called on it.
I responded to RAY ANDERSONS POST. As I stated some time ago, the OP was going to be rife with dumbarse questions for no other reason than spooning sloth, and that for my own sanity I've put him on "ignore"---curiously though it becomes clear he has not returned the courtesy, and selectively viewing what has been recently said while I make absolutely NO REFERENCE WHATSOEVER TO HIM AT ALL he chooses to become personal and make personal attacks which are uncalled for, and which reveal his mental capacity.
Nobody has to listen to my advice. I've told you how to automatically take me out of ever reading my posts again. Grow a set, while signed in, click in the upper right corner of the screen, click the triangle next to your screen name, click on "manage ignore prefs" and ENTER MY SCREEN NAME SO YOU WILL NEVER SEE MY POSTS, IM, SIGNATURE, NOTHING, NAND, ZILCH, ZIPPO!
If you're too stupid to follow those simple rules, and continue to bitch about what I post, then excuse me if I see you as a Whitney little bitch who obsesses about sand in her crack, yet refuses to get up and go take a shower! The remedy is there Barney Purple Dinosaur Lovers: USE IT AND QUIT YOUR IDLE BITCHFEST!