Tony D
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Posts posted by Tony D
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It most certainly does.
Volumetric efficiency is a ratio of the engine's airflow to the engine's displacement and rpm. The more air the engine flows' date=' the better the VE. Adding boost (positive manifold pressure) increases airflow to the engine, thus yilelding a higher VE.
The formula is VE= 3456 x cfm / displacement x rpm[/quote']
I would have to disagree!
You are confusing the issue here, and using a N/A VE formula which is inaplicable to a boosted operation---especially with a turbocharger.
VE will determine what BOOST you make, as boost is a relationship to restriction to FLOW!
If your VE goes up, with constant CFM to the engine, the Boost observed will DECREASE. Problem is a turbocharger is a variable displacement dynamic compressor feeding a positive displacement compressor (the engine).
VE refers to the efficiency of the positive displacement flow through the engine in reference to ideal cylinder filling.
The Turbocharger "Increases" VE by making the mass flowed through the engine increase, but the efficiency of the pumping action of the engine is not really changed at all.
If the VE of the engine actually increased, the turbo boost pressure shown would drop.
It's splitting hairs to be sure, and most people get lazy and simply use VE as that sort of generic term that relates to total mass flow through the engine, instead of the actual efficiency of the pumping action of the engine----which is actually what VE is supposed to refer.
VE increases come through decreasing pumping losses, and a turbo doesn't do that. It simply boosts the head pressure available for the engine to draw. in all actuality, the VE of the engine (as discussed obliquely above) remains the same----the formula should incorporate inlet pressure to the engine, and related mass flow (hidden in the constant of "3456" above, which only relates to an engine operating at atmospheric pressure). When you properly calculate it, the VE will not change appreciably when considering on boost or off-boost operation. A notable exception is the RB26DETT. When the VE is calculated on that engine off-boost, you find pumping losses are higher than when under boost. This was primarily because the inlet manifold was optimized for flow conditions under higher boost pressures, and not the lower pressures encountered while in N/A operation.
What you have stated is the same assumption of "Boost Compression Ratio" using two stages of compression and lumping them together as if they were a single system. That's not how it works!
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So you were using the old single SU draw through on top of the stock fuel injection? That's genious...
no, on one setup I ran a holley 750 draw through, and has hobbs switches and jets to dump fuel in the linet (egads, that I even ADMIT I did this...)
On another there were the ubiquitous Hobbs Switches dumping fuel in the manifold, as well as additional injectors BEFORE the turbo.
And FINALLY on a triple blowthrough, again, Hobbs switches with a spearco Injection system using carb jets, solenoids, and a big tank of "anti detonant"....
After Spearco Tech Rep got very uneasy finding out I was dumping fuel into the turbo inlet under boost using their non-fuel rated components.
So I switched at their insistence to "anti-detonant" which is open for further discussion.
On that final setup, I ran up to 22psi without an intercooler, but with injection before the turbo of fluid (take your pick: ethanol, methanol, water, isopropyl alcohol, windshield washer fluid...I ran all sorts of crap through that setup....)
BELIEVE ME, MEGASQUIRT IS FAR BETTER!
There is also a code available that controls an additional injector for anti-detonant injection before the turbo....... Uses the Fast Idle PWM circuitry I believe.
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Thanks for your reply' date=' but again i think i mis-worded. i already have an intercooler and would not even think about boosting without it.
the questions is: how much boost (with intercooler & megasquirt), 91 octane and 7.7:1 cr is safe? sorry for the confusion!
[/quote']Mr Fancypants said it again, and I'll reiterate it:
It depends more on manifold temperature and spark advance than just the octane and boost level!
If you have a GOOD intercooler, you can run MORE boost for the same situations. "Safe Boost"? No such thing! I have seen intercooled engines blow their pistons out at 8psi.
Run lean and all bets are off.
Same engine, running properly ran safely over 20 psi, and it was an 8.5:1 CR.
Boost is not the issue, temperature and spark advance, in conjunction with combustion chamber condition are!
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Tony D, you were injecting fuel in front of the compressor like a draw through? Was that supplemental to the regular fuel injection, or did you just have a draw through carb setup of some kind?
The answer: "Both"!
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To address the original topic question, why bother? Just get the Advance/Retard Can for the ZX dizzy from a European Spec L28ET.
They had a vacuum can that did EXACTLY that! They didn't need no stinkin' ECCS. They got no cat, a .82 A/R Turbine, no ECCS, no EGR, and 20 more HP than Stateside vehicles.
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Deleted a bunch of posts that MAY have had incorrect info. Basically if the thread started of with the words "I think maybe..." it got deleted. Just trying to keep things tidy a bit, hope no one takes offense.
Thank The Moderation Gawds, it HAD to be done!
Alan can post more information on the S20 (which was the original post topic) but suffice to say they were making well over 300HP on those engines in race prep with Mechanical FI. I wish another 87 432's were produced so that the S20 engine was legal for Bonneville Competition. I need a production run of 500 vehicles (to the general public) to homogolate the engine in the chassis, and using an injected S20 with the Mechanical Injection cam sets would give us about 100 more HP than we are currently making from the L20A in the Land Speed Car.
That would make a significant difference in the top speed!
I always wanted to produce a T-Shirt with a "No Honda" logo over the pocket, with the technical cutaway of the S20 Cam Drive and Head Setup on the back with the specifications of the Mechanical Fuel Injection engines. Something along the line of "The Real Type-R, GT-R 345HP, 10,500rpm, Fuel Injected, No Variable Valve Timing, 1972"
Kinda puts the Honda Boys in their place with their "Latest And Greatest Technology" boast, eh?
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I'm with Tim on this one. Take a look at general industry: NOBODY does multiple stages of compression without intercooling.
Why? Temperatures would quickly get out of hand.
And the temperatures (as well as combustion chamber ddesign) will play the majority of the parts in what octane you require.
Many people (myself included) have run 92 octane pump gas to some stupid pressures (in my case 17+psi) without an intercooler.
BUT THAT DOES NOT MEAN IT WASN'T INTERCOOLED!
At a point above about 10-12psi on pump gas (or about any gasoline for that matter) you end up enrichening the mix quite a bit past what you need for combustion, and retarding timing to keep it running without detonation. Gasoline becomes your anti-detonant. In my case it flashed off in the turbo and dropped outlet temperature of the turbo.
No matter which way you try to sort it, PV=nRT doesn't change. it's a physical law. You have to drop the temperature between stages of compression or the temps will soar exponentially.
For instance, (ballparking here) you have 80 degree day, and run 2:1 Compression ratio in your turbine. You are running just under 15 psi in your intake manifold. That air without intercooling will be (again, ballparking, offthe top of my head, no calculations done) anywhere from 180 to 270 degrees depending on your compressor efficiency.
No biggie, but you got another rise coming. (without boost you would go from atm to 87psi, in this case you will go from From 29 t 188 psi) in both cases the delta is exactly the same, thereforethe temp rise will be the same.
BUT, without cooling that 180 to 270 degree air, that 7:1 cr bump will jump that easily to auto-ignition range.
now drop that turbine outlet temperature from 180 to say 100, or even better, 80 degrees (through anti detonant injection or proper intercooling) and for all that pressure in the chamber, the temperature will remain the same.
if you can drop your intake charge to near ambient temperature, boost will really not be the issue. Blowing the spark kernel out of the plug gap, or combustion chamber design and hot spots will become the focus of your ire...
I don't know if this is answering your question, which I think is "how much boost before intercooling on what octane"---and the point I'm trying to get across is that one way or another you HAVE to drop the temperature in between the turbo and the cylinder. While you may not "intercool" it with a radiator, you end up with a defacto intercooler by dumping gasoline into the chamber or turbine inlet to flash off and cool te works before it compresses.
in the end anti-detonant is not as an efficient way of doing it, though you can run a lot of boost by injecting it right at turbine inlet. If you monitor that temperature, it will dictate what octane you will need.
Most Z-Cars with agressive spark timing (even N/A) will start spark knocking when the temperature is above 110 Ambient under any sort of load.
So any time your intake charge is appreciably above 100F with today's gasolines, you start taking timing out, or not being able to load it up really well.
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As posted above, the money they ONCE comanded was prodigious. But now with the availability of 2.9 gearsets/diffs from the Armada, their value is dropping as the diffy is stronger.
Now, with Subaru selling Torsen-Gleason R200's in their new Turbo Legacy, it's only a matter of time till they start showing up on the market and make things once made of "unobtanium" no longer worth what they once were.
No way I would pay upwards of $1000 for it, but indeed $500 would easily drop out of my wallet. The $1000 would be more for the old 3.08 gearset.
But as stated earlier, now with the Armada Pumpkins available, an even better ratio (and yes, it IS for a Land Speed Salt Flats Car) is available, for a price probably much less than that and with low miles as well!
Damn the march of "Product Improvement"! It shoots your hoarde's value right in the butt! LOL
Anyway, don't pay too much for that Torsen-Gleason R200, waiting a few more years and the chances of a cheap one simply showing up in a Northeastern Junkyard in the back end of a T2007 Turbo Legacy is HIGH!
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Use a thick enough Engine Plate, and the only thing rotated will be the engine, you can mount the tranny straight up, to the Engine Plate.
Then all you need to do is alter it to relocate the starter.
The Electromotive 280ZXT was laid over at almost 30 degrees towards the passenger's side of the car using dry sump, and allowing a long curved runner intake manifold.
What, only $40K in fabrication, nothing big....... LOL
It would probably be easier to relocate the driver's side using Fairlady Z parts to RHD, and really open up that side of the car. I know RS Okinawa used 5" exhaust on it's Twin-Turbo Setups in the Late 80's. But such is the advantage of RHD....
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Running across Iowa at 100-110mph in 103 degree June Heat, was at 170 with a 160 thermostat....with the A/C on and the interior of the car at 70 degrees. 1974 260Z, MSA 3-Core, Stock Fan and Clutch, no Shorud, no Splash Pan. 3.70 gearset, late ZX 5-Speed tranny.
Running 85mph towing an 800# trailer, with three people in the car, across the Texas Desert between ElPaso and the next outpost of civilization in 110 degree heat, ran 170 with a 160 thermostat, stock radiator, stock shroud, stock fan and clutch, stock splash pan. 3.9 gearset, early 5-Speed.
Running 3200 rpms across I10 to Phoenix from Palm Springs, in 120 degree heat, with 3.7 gearset, late ZX Tranny, on my 73 Turbo Conversion got to 180 degrees with a three core, electric fan, no spash pan, G-Nose, no shroud, and FMIC with 165 Chevy thermostat.
These temperatures were taken using a Thermocouple and my Multimeter converter plug-in box. Thermocouple installed in upper radiator hose in the water flow.
IN EACH CASE, EVEN THOUGH THE TEMPERATURES WERE WITHIN 10 DEGREES F, THE RESPECTIVE READING ON THE IN-CAR OEM STOCK GAUGE VARIED FROM LEFT OF CENTER TO THE MIDDLE OF "M" IN "TEMP"!!!
Moral of the story: THE STOCK GAUGE IS USELESS UNLESS YOU CALIBRATE IT TO A GOOD KNOWN GAUGE! (The 260Z, incidentally, has half a tank of gas, when it shows 1/4!!!) Same thing, old cars gauges drift, check em out and make sure they read right or you at least know the amount of drift!!!
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Does it do it if you DON'T snap-throttle rev it?
I had an issue with my timing offset and the high-map bins where on drop-throttle when the vacuum went high in the manifold, the spark would jump to the next terminal in sequence, and then STAY THERE until I shut the engine off and reset the box by turning the key of and back on.
Underboost, I was cool, no drop throttle from boost above 2500rpms, I was cool, but hit any of those 40degree advance bins, and Braaap,Bang,Pop,Poof, BANG!
Try taking all your high-vacuum bins to 30 degrees and see if it stops going nuts after you rev it. You may be jumping time one terminal ahead like I was doing!
My WAG! LOL
Good Luck
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heh heh heh, how did that old Viper work out against the Turbinator?
Too lazy to run through all the linking required to see it.
Though the LSR car was up there in 1999, I remember the Turbinator.
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Would you believe now we are running a 4.11 gearset? On 24 or 25" tires and a direct drive Datsun Comp Five Speed? You do the math, it's singing going through the traps at 141mph+ for the 2L Records.
With the 2.8, it was going through the traps at 8500 or thereabouts, running alternately a 3.9, 3.7, then for Bonneville a 3.36...
Most of the speed is made in the first mile at Bonneville, same as at El Mirage. After that, it's incremental speed increases. So yeah, it might enter mile 2 at 8300, and enter mile 3 at 8400, and go the final timing distance at th end of mile 3 at 8500 or 8550....
So yeah, for basically two miles it's running at 8500... That was after four seasons of racing every meet, and two trips to Bonneville each of those two years. The damage done that did in that engine was the pressed-fit piston pins walking out to the cylinder walls and scoring them .080" in all six cylinders. Blowing by like a mother, it still went 173.325mph... When we finish with the 2L, the freshened 2.8 is ready to go back in an bump that speed a bit more, and maybe get us on the long track (have to go 175+ in the 3 mile course to make it to the 5 mile long course). I figure we will make a bit more power without those .080" pin scores in the walls....
But not redline by any means, last meet at El Mirage trying to diagnose an intermittent sensor problem, the car was held at 9100rpm for 30-45 seconds at a stretch while we waited for the sensor error message to indicate.
Kinda Hairy, revving an engine without a load on it...
If it goes boom, it goes boom. Build another one, eh?
The conversation digresses...
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Being that DIS utilizes an actual crank trigger, there is NO spark scatter induced from the slop in the gears that drive the distributor quill shaft as well as the slop between the quill shaft and the distributor itself. Not too mention any pulsations from the oil pump being transmitted up though the quill shaft. Another advantage of DIS over a distributor is with DIS, you are also eliminating that extra gap that exists between the rotor and cap that the spark has to jump AND, no more cap and rotor to replace over time due to worn cap terminals which leads to deteriorated ignition performance. That is bad thing for highly boosted engines.
Even worse, and from personal experience: The gear on the distributor drive spindle can SPIN! It is NOT pinned to the quill shaft, and a backfire can cause enough harmonics to change your timing 7 degrees, or 187 degrees (ask me how I know this!).
The added advantage of havin a coil in an ideal situation with less than 6" of spark plug wire leading to it means FAR LESS SPARK LOSS. Sure, you can talk about distributor gap, but what that all leads up to is less energy to fire the plug under boost.
As for the "50 Degree" limit of a distributor, just for those that aren't making the connection, with 6 cylinders firing 60 degrees apart, if you advance your timing 50 degrees, chances are GREAT using a distributor you end up firing the cylinder INFRONT of the cylinder you intend to fire in the firing sequence. 153624 remember? In EDIS, or coil on plug that is ALWAYS the firing order you will have. Using a 280ZXT CAS with improper phasing, or even with 45 degrees advance you can skip time one terminal and go to 153324! (ask me how I know this, or read Moby's sticky on my 81CAS conversion to find out that once it jumps, it doesn't jump back!)
Short of coil-on-plug, EDIS is probably the most powerful spark you can give your engine in regards to usless parasitic losses of spark energy.
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You can also take an old .010†feeler gauge and using a pair of tin snips, cut up several small pieces that will fit within the spring retainer under the lash pad. <> Even a few pieces of .020†and .030†cut up for those really wild set ups is good idea to keep the stacking of .010†shims to a minimum, (Lash pads are sold in .010†increments). This approach to finding lash pad thickness works very well, especially for those only going through this process maybe once or twice a year. Much less expensive purchasing one example of all the available lash pads and is just as accurate.
Feeler Gauge Blades: Excellent idea! I have a lot of old Brass and Stainless Steel Shim Stock from doing motor alignments, but feeler gauges are cheap, and probably provide more than enough material for an individual setting up an engine. I have done similar things with that bulk sheet stock for years. I always had a problem telling people where to get shim stock in their local area outside of an industrial hardware store, that Sears Feeler Gauge idea is brilliant, Thanks! Glad I logged on today and read that!
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Tony D has always said that the L engine crank has some terrible harmonics at around 8.5k rpm.
Never ever have said any such things!
People should be wary about attributing quotes to me that have not passed from my lips!
I have ONLY stated that we ran our .040" L28 to 8500, and that was a function of the gearspacing in the transmission, and our power curve. Shifting at 8500 was possible, but in actual testing, and after almost four seasons of shifting at 8500 through all the gears, our fastest times and best speeds were had starting the vehicle in third gear with a push start, and shifting at 8500. Basically first and second were a waste of time.
So from that, I can see nearly sometime in the future someone will say "Tony D has said spending time in first and second on a road racing course is wasted time."
Please DON'T put words in my mouth, and RETRACT that comment! I never said it, and it is at a point where I will INSIST that you show me the place where YOU sourced that information saying I did!
As for the current LSR car, with the L20A crank, and 1998cc displacment, yes we are shifting at 9000+rpm (9300 initially) simply beause this engine is making peak power in the 8750rpm range. To hear an L-Engine revving for 30+ seconds above 9000rpm changes what you think about what an L-Engine sounds like!
Mind you, these are not "Redlines" they are "Shiftpoint" numbers. Currently the limiter on the 2.8 program was around 8700, and the 2.0 program is 9500.
Redline is more a function of valvetrain componentry than crankshaft harmonics, and first and second critical speeds.
But I digress, I chimed in here to say I NEVER said the quote above, in no place, at any time, and that the poster is inaccurately attributing statements to me that are false.
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Web Cam? BAH! I drove past their building returning the U-Haul auto transport today, I was wondering if they did L-Engine Cams, they are about 5 miles from my house!
I wish JeffP would chime in here, he knows what his stuff is in his car as well. The numbers you are giving are at .050, or gross numbers? His lift is (I think) in the .550"+ area, up from the former .485 on the Elgin Cam.
I'll have to ditto Sporks' comments on Lobe Separation and Lobe Center, they are two different things, and each will affect the engine in a different way.
Opening point on the cam will be different on a cam with an "X" degree lobe center, as opposed to one with a "Y" Center. And like James is saying, the 'separation' between the two lobe centers will affect overlap which gets critical with a turbo engine to prevent reversion.
And yes, seriously, Web Cams is 5 miles from my house, behind the U-Haul Regional Yard off the 60 fwy! LOL
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I'll throw into the mix that I just changed divisions at work, and no longer have access to the five-axis tracer machine back in Kentucky.
Originally the plan was to trace out a BCG head from JeffP's engine, since Nathan is not doing them any more, having the ability to five axis a port to exactly what it was before (within reason) on another head, or after a repair on the Bonneville car was the primary reason for this---but it would have given a nice model to reverse engineer what others are doing compared to one of the premier head porters in L-Engine History.
What I will do now is up in the air. I wanted to check the ports done by RS Okinawa back in the mid 80's and see how they compared, as they look very different, and obstensibly came from similar applications.
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"STOCK TURBO' date=' PORTED HEAD, PORTED INTAKE, WITH 9LB OF BOOST AND MADE 317HP TO THE REAR WHEELS"
a stock zxt motor makes what, 160hp? wow, 2lbs of boost, port work and that manifold produced 150+hp?
"HEADERS HAVE MADE OVER 800HP ON FULLY BUILT MOTORS "
and those cars would be . . . .where?[/quote']
Well, JeffP isn't using the stock turbo, but was running 300+ ft-lbs on a lean-running mistuned setup at 4900 rpm. At 8Lbs of boost.
And take a stroll through the dyno cell in 1983 at the Electramotive Works, and you wouldn't be far off from that number!
Porting the head makes for lots more flow---people need to understand boost is RESTRICTION TO FLOW. Boost is NOT required to make big power, IF you have set up the head and flow correctly. Gas in, gas out---the more efficient you make it (just like an N/A, you can't fool physics!) the more power you make!
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Yes, that is the key: "MolWeight"
When designing flows and capacities in stationary multi-stage centrifugal compressors, humidity is a critical facto that has to be accounted for when determining flow delivered to the customer, as well as determining what size the condensate removal piping will have to be.
After the first stage of compression, all compressed air (short of refrigerating the air for desiccation) is 100% RH, and that is one of the reasons the first stage is usually disporportionately larger than the relative sizes between second and third stage, or subsequent stages of the machine.
Which leads into the next subject: Freon intercoolers....
if you have 100% RH at 9-10 degrees F above ambient from your A/A interfooler, just imagine the density boost you would get by desiccating the air in a freon intercooler and dropping the inlet temperature down to 35F.
For a short run drag car (er, or Bonneville Car) a battery powered electric compressor would make a big difference in power. And even with a tap off the vehicle's A/C system, the net gain in power would more than offset the drag of an intermittent compressor operating drag...
But I digress...
Water displaces air that could be there. And the hotter the air, the more water it can hold. The amount of water that air hold jumps dramatically from 85F to 104F, it's a factor of what can be held at a lower temperature, and for all intents and purposes, if the air is above 120F the amount of water it can entrain as water vapor is jumped by another factor!
In many cases, with multi-stage stationary compressors that are air cooled (interstage cooler), design will dictate savings by deleting condensate removal on the first stage of cooling, simply by desinging the second stage inlet to operate at <120F, and spinning the second stage slightly faster to make up for the less dense air.
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check with Bryan Blake, I believe, matter of fact I'm sure, he is using that funky dual relay in the 75 to 78 280Z to control his EFI power and Fuel Pump...
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I did some swapping while in Japan, and I found that the L20 Maifolds make for SEARING throttle response and phenomenal torque down low.
Now that also goes with the engine falling flat on it's face by 550 FOR SURE.
But with an L20E intake manifold on an L28, using L20ET Injectors on the stock L20E ECU and AFM, the car I did that swap on, when in a sweeping turn would absolutely BOIL the tires with instant torque when I follred the throttle at 2000rpms.
So if you are building a stoplight performer, don't discount those small runners on the L20 Manifolds!
Vlowcity velocity velocity! That little step at the head is nice for anti-reversion as well, helping with dilution of the charge while under boost due to exhaust backpressure.
Just some random thoughts! Good Luck on the build.
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Which heads don't have the notches for the efi injectors?
E31, E88, some JDM N42's, just about anything on any engine before 75.
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The Carburetted Engines would simply need a slightly different angle to clear the port. I don't know how thick the flange is, but by my measurements a simple angle change should shoot the fuel where it needs to be or simply spacing the injector back fro mthe port a bit would do nicely.
I like the idea of the injector mounted in the flange personally, because it takes the variable out of putting them in a tubular runner and accurately positioning them.
Then again, I may be running a dual injector system with idle/emissions injectors near the head, and the real business out near the plenum.
Making a set of "dummy plug" injector bodies for the standard flange would be easy enough if someone chose to move the injectors elsewhere.
That's my thought on it anyways.
[/quote']
My notes for 83zxt to MSnS-e on v3 PCB (Hall and VB921)
in MegaSquirt
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I'm going to mention for no other reason than I saw it above, that I am using CHT on my 260ZT conversion, and scaled it using Easytherm, and it's dead spot-on. Temperature I read there during idle is lower than thermostat housing, but during loaded operation and acceleration is about 10 degrees higher than thermostat housing. So it's seemingly a more sensitive location based on load, which is probably a good thing.
If you are having spark issues, and you are using an HEI in any service whatsoever, don't use a cheap one! i had an Autozone Wells part for a while and was disgusted by the spark quality from it. Upgraded to a Pertronix unit and spark quality was dramatically increased. Of course, that upgrade came after the Wells part fried itself after only about a coule weeks of intermittent troubleshooting. After that, the Pertronix unit has functioned flawlessly.
On running and then not running. Occasionally the thing gets corrupted. Perhaps the Ms got a static discharge through the box, and the chip got a bit freaked. Have you tried reloading the software and trying it again? I had that issue when I was originally doing the setup. Running fine, then blah baaah blahhh buu buu buu..... Bang my head against the wall for a few weeks then finally reload the program and everything is fine again. ???????
just a thought...