Tony D
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Posts posted by Tony D
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I just ordered Corky Bell's books "Maximum Boost!" and "Supercharged" and hopefully they will have answers to my questions.
Unfortunately tthey are over ten years old, and have relatively dated information in them. They will give a genaeral overview, but many of the statements in there can mislead you. They were a standard and totally relavent when they were originally written, but now they are out-of-date in regards to what current state of the art technology exists.
As for your question on compound charging, yes, that is about how it would work, but you will HAVE to intercool that 7psi on the turbo back to ambient or you will have hellacious discharge temperature issues on the supercharge outlet. Yes, with the turbo putting 7psiG into the SC at a 1.5:1 CR, then you would get 18.375 using your example.
The total compression ratio across the powerplant would be 3:1 and your discharge from the supercharger would be 350degrees F or thereabouts giving a ballpark guess. So intercooling of the first stage of compression no longer becomes optional, it becomes mandatory. You could inject something like Methanol to take that heat out, but however you choose to do it, the inlet to the supercharger will be limited to roughly 100F maximum of you will be in sad shape with octane requirements.
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There are two different units available on E-Bay right now.
The NISMO unit for $96, and a Kameari for $200+. Both in the USA.
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Someone who is infrequent on this forum currently has converted SU's with 1000 cc/min injectors in them running on his 3.0L Racer, we were supposed to do a joint dyno day Friday, but everything fell through. So tuning of the final maps and 'decisions' to be made about injector placement of the two injectors still remains up in the air till that dyno testing is concluded.
This setup is the 'ultimate quick and dirty' EFI conversion of SU's. The results should prove very educational.
Pete, you have 'peripheral knowledge' of his setup. I've no real photos to speak of thusfar, when I do, I can distribute them.
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It's an intake manifold designed for a draw-through setup. The turbo discharge goes to the round connection in the center, and the Four Barrel adapter or SU adapter goes on the inlet of the Turbo.
Oooold technology. They perform fairly well, and that one gives a slightly better finished look to the engine bay than the old crown-adapter that just bolted on the SU manifolds in place of the carburettor.
Why are people in the club keeping these treasures from me? I should really check out our club site more often! LOL
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I'll weigh in here about the 'area under the curve' is a bit misleading. What needs to be considered is how would this system compare to a front-mounted low-boost turbo system, and not it's N/A counterpart.
I know on several 'small twin' setups using twin T-3's with integral wastegates the performance was phenomenal right off idle---7psi was available on a cobble-job of two 280ZXT turbos mounted on a box-tubing fabricated set of exhaust manifolds from around 1500rpm. Torque was WAAAY up compared to before forced induction, and I'd guess it was far better than this system under similar conditions. Performance was pretty much done by 5500 anyway, which looks to be the same situation with the STS system.
I'd be wary of attributing any of the STS issues to lag---I'd expect their turbines to be sized to have threshold outside light cruise, and with the air moving true 'lag' should not be an issue. In the front mounted examples I've toyed around with, we could get boost threshold at 1500-2000 fairly easily, and given stall speeds on Impalas (don't ask!) with autoboxes, that means for almost supercharger-like boost response.
Were I to do a V8Z and turbo it, I would set them up front rather than out back.
On a new Vette.... maybe out back makes sense. I'd agree it's a system for when a proper setup can not be employed, or as someone stated 'stealth'. Using an intercooler would kill the 'stealth aspect', and also limit the total boost that was useable to less than 10psi. But taking a look at a Vortech Supercharger would cause me to take pause about the troubles related to putting all that out back in comparison to an engineered kit up front...
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i have noticed considerable power loss
That's odd, usually when they are on the edge of 'too cold' they will kick in the cold start system and the richening helps on the top end.
There may be other forces at work unrelated to the thermostat.
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I see someone else has the same aversion to the 'shadetree' terminology as I do...
LOL
Are you sure we aren't somehow related? LOL
Tip: Seal the edges with something like aviation sealer, etc before driving them in. I've also known people to use 1/2 tube of alumaseal in every engine after assembly and initial start (Ford and Volvo being two of them...) to preclude any weeping from unclean or nicked core plug bores (amongst other things).
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I have to agree with Pop N Wood, the radiator guy may be a fine soldering technican but he has a long was to go to understanding what actually happens inside the engine's cooling system!
I run a 160 thermostat for a number of reasons. Braap hit manyn of them on the head. But from an underhood analysis of engine components using surface contact probes, thermocouples, and I-R non-contact thermo guns, I came to a realization that in 110 F heat in the desert, the 160 degree thermostat keeps EVERYTHING under the hood cooler!
Running a 195 thermostat, on an 85 degree day would result in some underhood components like the fuel rail (75 EFI engine) to run well over 160 degrees. Many of the components nearby the block were also considerably hotter. Switching to the 160 degree thermostat would cool formerly searing components to something that is cool enough to touch with a bare hand! (Less than 140)
I have see similar reductions on Carbbed Cars as well. I think the reason the vapor lock problem subsized on my 240 was because the underhood radiated heat load was so much lower and the fuel was not baked as much.
I run the 160 on stock radiators, three cores, and four cores all with similar results. I'm in a rush now, so can't detail a lot of the testing, but I change my thermostats twice. Once when summer comes to 160, and on the car that takes short trips, to 180 in the winter. If it is my 'highway car' I run 160 year round down in SoCal.
Overall, the temperature of the stock EFI cold-start system usually is satisfied (170-175F) by running the 160. Remember it only starts opening at 160, it is not FULLY opened allowing flow until at LEAST 10F higher! Litte known fact...and confirmed by my underhood temp chasing.
Be forewarned, in desert driving on a clear day there are not a lot of aerosols to block UV, I have seen 160 degree thermal layers (the air that actually passes through the radiator) on top of the Macadam surface of the roadways on as little as an 85 degree day! In comparison, in Iowa with heavy aerosols blocking UV, I have recorded 110 F thermal layers on I80 on a 103 Ambient day!
The reaction of the radiator to the temperature of the air passing through it can not be discounted. If you are overheating up north, you will play hell down south where the actual cooling air is schorchingly hot! And thermostats will only help somewhat. Make sure it all is in good condition, or slow it down so imparted heatload is less.
My car runs cooler at 65mph than it does at 55! Odd, huh?
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I figured that real fairladys here in the states would be closer to 6-7k in the states
Hey, I've got a nice donor ZX that I'm SURE my wife will let me sell to you for that price!
Seriously though, on the west coast, they are up all the time for under $5K, WELL under 5K.
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Meh, no problem.
I end up finding 'long lost friends' whenever they find I've made my 'cheese run'.
When I was overseas, I literally flew 75# back as checked bagage, and it was GONE within a month!
You know cheeseheads, once they find it it's like rats to a corpse till it's all gone! LOL
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That beats lighting them on fire and beating on them till they fall out in a smoky, firey pile on the driveway...
But not nearly as cathartic! LOL
Nice tip.
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Quick Thrash before MSA AutoX few years ago (when it was at Irwindale) and my wifes 260 was skipping beats and then just died. Half tank of gas....
Long story short: Had unwittingly swapped return and supply lines back at the tank. On the roadside sucking on them did not reveal which was which (of course!) Picture this conversation I was having on the cel phone:
Pull it off, then suck on it. Suck on it and see if anything comes out.
Listen honey, if you won't suck on it we're not getting anywhere, I need to know if you can get anything to come out!
SUCK HARD, HARDER THAN YOU THINK YOU HAVE TO! It came out? What about the other one?
Yeah, you're going to have to suck on that one too. I know, I know, just spit it out! On the other one, when you feel it coming up just suck shorter sucks so you don't get a mouthful....
People were looking at me funny, and I was totally oblivious till my bud Larry came up to me laughing and said: "Dude, you should have heard what you sounded like on the phone!"
Later that day, and after the AutoX... DUUUH! Got BOTH the jokes then...
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FYI: The stock ZXT turbine outlet casting and the stock headpipe, cut juuuust before the catalyst will mate up perfectly with the MSA 2.5" mandrel-bent exhaust system they sell for the early S30's. You have to trim one pipe in the kit with a hacksaw depending on where you cut the ZXT headpipe, but it's very close and the pipe diameter is the same. A slight reindexing of the headpipe towards the center of the car helps with packaging as well.
For $149 you will have a nice mandrel bent exhaust that will serve you well in lower horsepower levels, and if you ever decide to upsize, you have an almost perfect 3" template for your upgrade.
There are things you can do to make it fit up tighter under the body in back such as grinding the R200 machining flange off as well, but that's not for discussion here, now, anyway.
Makes for a quick install on someone doing a weekend conversion who doesn't have access to a welder or exhaust shop within 'open header driving distance'....
For a 2+2, just add a section of 2.5" piping from the local Pep-Boys or Canadian Tire (hey, how continentially inclusive, EH?) and you're set!
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"Root Diameter" not the "Pitch Diameter"
Translated:
"Pitch Diameter" is the outermost portion of the threads.
"Root Diameter" is technically the valley of the threads, and should be close to the 'size' of the bolt. The "Shank" of the bolt---that is the portion of the bolt from the threads to the head---may or may not be the 'size' due to different design parameters. Sometimes it's larger, sometimes the same, sometimes (like in Aircraft Fasteners and Studs) it is quite a bit less.
One day, I will get 'the bill' to you Paul. Still working on Taxes! >:^( Getting closer though! :^)
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Good point, yeah, WOT. I don't think it's a viable way to test it anyway.
Like you mentioned, getting onto a hill, with a VOM and piercing probes in the correct wires, and going WOT in fourth gear will creep you up to the point where you can read the correct voltage.
Nobody said tweaking the stock system was easy, right? LOL
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He he he.... his first dyno run down at Jim Wolf was showing 381 Ft-Lbs at 8.39psi at 4500rpm....and that was when he sunk rings on five pistons because it started running lean at 5525rpm when the ECU went from single fire to twice a cycle firing of the injectors!
He has since surpassed that mark with the correct tuning of the fuel curve.
And to answer that question, yes, he is into pain. Matter of fact, I spent two hours last Friday running a Mustang dyno for him while he ran the map on the ECU again. We got RIIIIIIIGHT up to the section where he formerly was having problems and an alternator diode toasted, and melted the lo-temp solder out of the rectifier block stopping our dyno running for the day. And to be honest, the first 30-45 minutes of that was me learning how to run the thing the most efficient way to get the car up to load quick enough to do what we needed to do. Once we got a routine down, we were mapping four blocks on his ECU at a time. The interface he has for the fuel table is very much like a standalone setup, it allows reburning of the stock ECU in a similar fashion.
The problem Jeff is up against now is that there is a point two places on the stock Z31 box where the ECU rescales the map. The first one is relatively low load and low rpm---they use a lot of the OEM for off-idle drivability which is understandable from an emissions and customer satisfaction standpoint. The SECOND switching point is where it will make or break wether the stock Z31 ECU will be able to support the system to the full 600+ HP Jeff wants. I recently dug up an old photo I had taken of Steve Mitchell's Z31, and was shocked to find that Steve's dyno chart had the SAME DIP at 6300rpms that Jeff was experiencing in his setup. Since JeffP formerly made his 415 RWHP number at 5800rpm and 23psi, this ECU anomaly was not an issue. And we had never really discussed with Steve where he was making his 600+ from (730+ ft-lbs of torque!!!) From the dyno shot I had taken, it became clear that Steve's unit was well past horsepower peak, so the dip was not an issue. On JEFFP'S runs, though, he is peaking now at 7000-7300rpm, so that calculation comes right in an area where you don't want an ECU farting and deciding to rescale the map and think about what pulsewidth it should be sending out to the injectors!
Formerly this was evidenced by a quick spike in AFR to VERY lean (under boost---BAAAAD!), and then to a PIG RICH situation which took a few to recover from.
On our final pulls we were jumping to 12.8 and 13.0 AFR under boost. We were not detonating like before, but the jump was still there. Jeff had JUST put in some parameters to alter the fuel block there to see if it would compensate, and on that run the car started misfiring, though we didn't see the dip before we shut it down. When we shut it down to cool, Jeff added even MORE fuel into the block in an effort to turn the lean spike into a rich spike which would tell us if we could get through that portion of the map without the former problem...and when we started up again, all the AFR's were 1 point leaner than they were before....and Jeff Discovered he was no longer putting out 14.1VDC from his alternator.
DENIED!
So hopefully we can get contact with someone at the dyno place and show up there tomorrow and FIND OUT ONCE AND FOR ALL if the stock Z31 ECU will handle a 600+ HP L28.
He ALREADY has the standalone purchased if the blocks won't work, and he then will know the limitations of the Z31 Box which is the theory he is testing. It's a great bunch of information for people to know if they are planning on using the Z31 ECU. It can handle and make a GOB of horsepower, but to do it you will have to BOOST the hell out of it because at this point it doesn't look like it will handle it over 6200rpms due to that recalculation routine. The software he is using should become available soon, and it will make for a viable option for people who want to use junkyard parts to tune their vehicles similarly to a standalone. It will easily support 450HP...
Jeff considered the M30 Box, but I deviled him to the standalone route. ;^P
But yeah, he was making 381 Ft-Lbs at 8.39psi of boost at 4500rpm, so 350HP at 7psi should be easily doable. The dyno is irreplaceable BTW. Wheel speed preceeding his 'problem area blocks' are requiring a 13% grade and making passes from 80 to 110mph...kind of difficult to do on the street!
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Yes.
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On an N/A car it should come to 3500 and that flap should be wide open regardless of load. On a TURBO car, then, YES---then the car must be under load for the turbo to load up fully and suck the proper amount of air to "pin the flap".
Like I said, the systems all interact. If you are trying to avoid work DITCH the stock system. To tweak it closely and properly is FAR MORE effort than the couple of hours needed to hack the harness and install the MS-n-S, AND TUNE IT FOR BETTER THAN STOCK DRIVABILITY!
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When you refer to "inherent intercooling", is this just the latent heat of vaporization of the gasoline.
Yerpo!
Quite a great effect actually. In this regard, it should actually be said the Blowthrough is the one that is limited, to about 10psi in regards to boost without intercooling.
A bolt-on Drawthrough can easily manage 17psi simply due to the fact that the carburettors fuel is impinging on the turbine blades and flashing to vapor during the compression process.
The latest trend in smaller Oil Free Industrial Compressors is to use "isothermal compression" using a water-injected screw element. The temperature of the compressed air leaving the element is nearly identical to the temperature of the air ENTERING the element. Revolutionary process in smal packages. Instead of air entering at 85 F and Exiting the typical Oil-Flooded Screw Compressor at 165-175 F, it exits more closer to 90 F, and the water is recovered and separated using conventional means. Imagine that compressor on the front-end of your Z: 125Psi Manifold Pressure at 100% R/H!
Turbine Discharge Pressure and Temperature is quite different between the draw-through and blow-through. At say 150Kpa, or 6.5 Psi thereabouts the stock 280ZXT has a discharge temperature of around 60C given a 28C ambient. On the same application in drawthrough, your discharge temperature would be hard pressed to break 40C.
Quite a difference! Of course as you up the pressure, so do you up the temperature produced. The manifold temperature will remain constant as more and more of the gasoline is vaporized (at 6psi there are still liquid fuel droplets to puddle in your manifold....muhahahaha!) to the point where you start to see a rise in manifold temperature.
It is at that point, using thermometers and thermocouples that you use your old trusty and reliable Two-Stage Spearco Water Injection system to spray methanol, windshield washer fluid, or water into the manifold to act as a supplemental anti-detonant.
With this system operating, your boost then went to 20+ easily, depending on your carburettion. A Single Z SU on a Turbo Corvair would not supply enough fuel through a .125" mainjet to keep from detonating at 17psi, a drawthrough Z SU on a similarly-sized 240Z with the same Corvair Turbo driving the Crown Turbo kit was almost identical in terms of detonation. You had to supply anti-detonant to make 17psi reliably.
BUT, put a Holley 650 on either of them, and MAN! 17psi? No problem. Being we are talking stone-age NON-WASTEGATED systems here, once you got to the 17psi you were effectively choked on the Corvair Turbo in either setup. Derestrict the front end some more, and then you saw that old Vair Turbo (or the Rajay Equivalent) would make upwards of 20 psi! And knock knock knock 'Mr Holey Piston' started sniffing aroudn again... So back to Spearco to stop the Knocks, and then you keep your foot into it till about 22-23psi where you surged the damn thing. Boost was totally dependent on your right foot in those old systems.
I actually long pondered reinstalling my Crown Kit on the 240 as a period resto, but instead using the stock wastegated turbo and a manual boost control valve. The problem with the early kits was they really relied on inlet and exhaust restrictions to keep the boost under control...gawd help you if your Turbo Vair shook it's muffler off or got a sizeable exhaust leak: you would detonate the thing to DEATH in an overboost condition due to tunaway turbine speed! I was thinking restricting the boost would allow me to conquer the woes of the old SU setup.... Of course I was also thinking of driving the thing with twin 550CC fuel injectors and a Megasquirt so it LOOKED vintage, but DROVE MODERN!
Looks are a big thing, and something that looks old, and vintage-period correct is really neat IMO...especially if you can hide the technology and actually enjoy the ride. I know tuning the MS and twin 550's would be FAR easier than what I had to do in 79...... That took literally WEEKS after work with the hood off, watching the station pole in the top of the SU and listening for detonation sitting unbelted BACKWARDS looking out the back window while a friend drove the car...
Ugh... you made me remember...YOU BASTARD!
LOL
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The 'baffle pipe' is actually the return line on a 280Z tank. On the ZX, the return line swirls in the pot.
That 'through the baffle' line likes to get obstructed right at the first 90 degree turn inside the tank and remind you why you can't be cheap and use normal carburetted fuel line on the 'return line because it's just a return line there's no pressure in it anyway'.... When it blows up and you hear this "SSSSSSSSSSSS" and smell a STRONG gas odor from the back of the car you get out to look and wonder "what's all that on the driveway?" about the same time you drop down to see the fuel spraying like crazy all over your exhaust pipe and onto the ground from the ruptured line...
Not that this has EVER happend to me. Not that I try to be cheap and skip replacing stuff...
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Oh GAWD! I SHUDDER to see those photos.
I originally knocked off the HKS Type 1 Plenum on my 73, and it worked great save for me being an idiot and not tapering the front of the thing to clear my hood. At idle: knock knock knock knock..... Till my hood 'autoclearanced'---then the knock was intermittent.
So to get something that 'looked better' I figured to make a simple box like the Cartech Plenum, and like everybody else was running here in the USA.
WHAT AN ABYSMAL MISTAKE!
First, my mileage with 44 Mikuinis and the HKS Type 1 Knockoff was averaging 17mpg in daily commuting to and from Corona and Brea through Carbon Canyon.
Put the Plain Box on, and my car started lean surging at light cruise. Had to up the jet sizes. Mileage went...er...down. Still had an annoying pop at light cruise that would NOT go away.
Boost response was MUCH quicker and harder with the smaller volume plenum of the 2X4 Box, but going to 3psi on every light throttle application is not the best for mileage either.
In short, the SK and the HKS both incorporate different methods of "Modulator Rings" which are present in the Maserati BiTurbo, a car that was OEM with a blowthrough turbo and Dual Dellorto DHLAs (think Mikuini or Weber).
These modulator rings in the Maserati, and the two-plenum or internal baffled design of the SK and HKS boxes allow for a slight pressure differential between what is pushing down on the float bowl, and what is actually present in the main venturi of the carb. This raises the fuel level, richening the mixture ON BOOST ONLY while keeping the SAME smaller N/A size jetting. At higher flows, the pressure differential is more acute, and the richening is greater.
The HKS and SK boxes take two different methods for approaching the pressure differential that is better than the Maserati approach of the modulator rings. HKS uses a two-plenum approach whereby the boost enters the top of the plenum box first, pressurizing the floatbowls slightly before the lower plenum is pressurized for the main bores---there are two cast in holes in the dividing wall between upper and lower plenum to regulate the differenital at higher flows. Some racers really hogged out those holes on high-horsepower setups. SK used a baffle to direct the air to the float bowl vent holes in a dynamic way, and then divert it to the main bores past a static diffuser that let the air enter at lower velocity and lower pressure. Maserati used smaller than open bore rings in front of each main throttle bore. You can screw with the rings for a while to line it all out. Generally the modulator rings are of the same diameter as the main venturi/choke, on a Mikuini 44 say somwhere between 34-36mm for a choke size of 34mm. They don't cause a flow impediment at lower airflows, but under boost they start righening the mix.
That, from what I have discerned is the MAJOR difference that made the car run SO MUCH BETTER on HKS-Style boxes, than on the simple Cartech Style Box... I NEVER DID get the thing to stop lean popping after the switchover. If it wasn't for that damnable Cartech-Style box, I'd still be driving my blowthrough HKS Knockoff now! I really didn't have many drivability issues with that setup---and I'm thinking since Cartech was the predominant setup here in the USA I can understand why some have such a distaste for them. The drivability and fuel mileage on the HKS was worlds better than the other plenum.
Though I could get as low as 5mpg when driving spunkily...LOL
Heat soak during stop and go driving on a non-intercooled setup was another issue but it was probably equal in both setups HKS and Cartech. I was running 17psi+ without an intercooler (there were anti-detonant measures) but no matter what, when I was running long and hard at 10psi (before the coolant would kick in) those carb bodies would heatsoak like a big dawg...
And THAT is where EFI comes in! LOL
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I've hoisted my L28 Complete from the rafter of my Tuff-Shed to put it on the engine stand.
Obviously now I have 'the Container' and can simply clevis some Gr 80 Chain across the top tie hooks and hoist them with the chainfall that way.
In and out of the car....oh man, concrete is SUCH a luxury! You guys don't know how good you got it!
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No, I'm a a$$, really! just ask the folks at ZC.C in the "Tony D Voodoo Doll Collector's Club"
LOL
Some of the sharks are circling now on one post in particular. How entertaining...
One of my best Torque Specifications came from the Cooper-Bessemer Manual, Head Bolt Torque for a GMVHS V16 Natural Gas Integral Compressor:
9 Foot Bar, Six Men, Strong Pull.
Matter of fact, almost ALL the torque specs for that engine were quoted that way---something designed in the early 1930's. I could just see those guys doing that! Eventually they succumbed due to pressure from NASA/JPL and in the early-mid 90's converted them to actual REAL foot-pounds. Those head bolts were torqued to 1600 ft-lbs. 8 per head, 16 heads. Plus the compressor section...
I can imagine that the last bolt torqued by the 1930's methodology might just maybe might have a tad less torque on it than the first one done on the other side if they kept the same crew torquing all the them! Heck I would do em all using a torque multiplier and 600 ft-lb Snap On torque wrench and then take a break! Manually? "The days when men were men!" LOL
Yeah, I felt REALLY priviledged to grow up in the age of Pneumatic and Hydraulic Wrenches!
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Like I said, if you tighten the spring too tightly, and the ECU gets funky signals and doesn't process them right. Tightening the srping RAISES the RPM whereby the ecu reverts to "preprogrammed" WOT injector pulsewidths. You experience confirms this....eventually your AFR's should have gone back to the same 11.8-12.0 when the Flap reached the 'full open' position.
But if it doesn't reach that by the time the ECU reaches 3500rpm, where it's SUPPOSED to go back into open loop regardless....
See what I mean about confused ECU?
There is a fine line between this tweak and that tweak, and in many cases, simply because of the way the system is designed, you can't adjust just ONE variable at a time---you end up affecting more than one because of the way the program interacts.
What you need to realize is that while the flap is in play, and the O2 sensor is active (if you don't have a heated O2 sensor on the ECCS this may never happen) the O2 sensor wil ltrim another 10% out of your fuel. As long as the injectors you added did not exceed the 10% range this should occur. You can NOT adjust to 14.7 by the AFM, it has to be slightly RICH and the O2 sensor has to do the final trim or it will never work.
With the size injectors you have you are supplying 15% more fuel than stock, juuuuust outside the O2 sensor's range. Did you try only two or three clicks, and make sure your O2 sensor feedback loop was being enabled? (The flashing lights under the ECU?) If the O2 sensor is not working, the ECU will default to the 'safe' program, and that only compounds the issue. If it sees rich for (I forget the number) X cycles or seconds, it reverts to the failsafe map---which isn't the greatest under boost. If you are cruising at 13's the O2 sensor is dead, try replacing it with the heated type from an 87 Z31 T and try tweaking a bit more. Those mods aren't so bad they would disable the O2 circuit, you are right on the edge of plug-n-play actually.
Strut Shortening - AZ guys
in Brakes, Wheels, Suspension and Chassis
Posted
Ahhhhh, good old USAF Plant 44...I know it well! Good work comes out of there. Glad to see you got some payback from years of experience locally!