Tony D

Yes, they are measuring actual flow through the barrel. The important thing in the synch is not only that all three carburettors are flowing the same (and you can use HVAC stuff, CFM is fine, FPM is fine---so long as they are ALL flowing similarly) but that each barrel in each individual carb is flowing the same! Mikuinis are notorious for sticking and then tweaking their throttle shafts. I have seen VERY serious flow differences between barrels from tweaked / twisted throttle shafts! So that is another check you are doing. As for 'old school' I synched carbs for years using the back of my fingers and judging the 'flow' across and between my fingers. People with a unisynch would literally stomp their feet in defiance as to how I could do that! For years motorcycle guys used multiple manometers to set the balance on thier multiple setups, and I recently bought a Gunson's setup that had a similar float setup to a Unisynch, but used a VERY BIG fixed orifice, and a small tube with floating ring in it---so it can measure very fine differences in airflow while not restricting the flow to any one cylinder. You can leave it connected while the engine idles. So that would be very similar to your setup proposed, Sven. Yours would probably be more accurate. I know with the new digital manometers I have been tempted to hook them up to the Gunsons' setup to actually Digitize the readout. But putting a $500 digital precision manometer kind of defeats the purpose of me buying a 12 Pound Sterling Gunson's Plastic Synchroniser Gadget...LOL I like the Weber meter because it gives a number and does not alter the airflow through the cylinder. If you use a Uni-Synch to get a decent reading you end up choking the cylinder you put it on---so you either take a series of quick 'flash readings' and move on...or you risk the engine slowing down and giving you a false low reading. The Weber unit can sit there all day and not affect how the engine gets it's air. And to do an off-idle check---say at 2000rpms---with a UNi-Synch? FAGGADEBAUDIT! WIth the Weber, you pull a plug and it rescales as more air is bypassed around the sensing element, giving you a reading you can read cylinder to cylinder without killing or altering the speed one whit. Actual measurement of the idle, AND OFF IDLE synch of the carbs! As for doing a cylinder balance test that is how I still do it. Curiously now I do it by removing injector connections! Singles out a dirty or misfiring injector QUICK! I have also used the garden hose method. Still use it today for detonation checks while driving... Imagine that sight driving down the road and passing a guy lugging his turbo Z up a hill holding a green garden hose to his ear straining with a look of consternation on his face!!! LOL

Send me an e-mail or your e-mail addy, I have some photos that may spur you to start working on that thing! The 73 Float Bowls are BIG, and the 74's aren't. So if they are 73 Flat Tops, you can easily set up some Ford TBI injectors from HO 5.0's in there at a 45 degree angle so the spray impinges on the center of the throttle plate. This is NOT ideal I have found... so a steeper angle will have to be employed in the SECOND set of prototypes... But add a .750" spacer to the float bowl, mill down the heat shield standoffs an equal amount, and cut a hole in the bottom so the injector connecctor can stick through and NOBODY from underneath or on top can tell they are fuel injected. Then you drill out the stock fuel passage in the carb to .250", and you can run the stock fuel rail with EFI hose directly to the carburettors deadheaded. Stick that asbestos insulation on the rail and the hoses...and who can tell? Use the stock ZXT regulator on the return line (orifice removed, and then the regulator set inline as a variable return orifice....) and you're set. EFI pump in the back, with a 280Z tank...nobody sees nothing. TPS? Simple, easily hidden under the dashboard, or use a GM unit with a 'key drive' right on the end of the throttle linkage---doubt anyone will even look that close, and coincidentally it's right under the valve cover breather. Not that I've given it any thought, WW. No....not at all. If only I'd REAMED those fuel rails instead of DRILLING them, I'd be using them NOW! I have a fuel leak issue to contend with...I know what I have to do, just no time to do it!

Yeah compression ratios are multiples of each other. I don't know why the hell I typed 3, that doesn't work out on my example! DOH! The math is right, what I wrote there was wrong. The total compression ratio is 2.25 (1.5*1.5=2.25) As for books.... there was this one undergraduate text that was 894 pages and was once available from OPMAP Technical Books back in the mid 90's called 'Turbocharging the Internal Combustion Engine' but I forget publisher and author. It wasn't cheap. Your better bet may be to cozy up to someone with an SAE Membership and get some of the recent technical papers on the subject. Kind of dry reading, but if you can handle the math there are no suprises! Garrett (Honeywell) Engine Boosting Systems R&D Complex isn't that far from me, and I get to talk to those guys in the course of my work... So next time I'm over there I'll see if they have any suggestions. Man, their shop has ALL the cool stuff. They can replicate just about any intercooler you ever could want! Oven for brazing the tube sheets, machine to make the fins between the tubes.... I salivate heavily whenever I'm in there!!! Oh, and the humanities! PALLETS of racing turbos (titanium cases, non-containment style scrolls!) All scrap.... Trash... Oh it hurts sometimes. I have learned not to open boxes on the 'scrap dock' for fear of being traumatized for the rest of the day. Same rule applies at Hewlett-Packard in Boise ID, as well...

Oh, I was being facetious... Damn! I think JeffP had a mainline to get those cheaper. Ah well, if you got it under $200 you did O.K.

Think of it this way: You flow 12cfm in one cylinder, and in the one next to it you flow 10cfm. (Unsynchronised) So you set your jetting so that with the colortune you get the optimum AFR in each cylinder respectively. The one with 12cfm is flowing more 'pounds per hour' of air, stands to reason, right? So that means it needs more 'pounds per hour of fuel' to get that correct AFR. And you know that (roughly) for every half a pound of fuel burned, you get one horsepower (This is a REALLY simplified version so he can follow it, don't crucify me for oversimpliufication!). Meaning that the cylinder flowing the ideal AFR for 12CFM will make MORE horsepower than one flowing only 10CFM. It's roughly the same as having 6 single-cylinder Briggs-n-Stratton Lawnmower Engines running all onto the same crankshaft: you don't want one at 1/2 throttle, three at wide open, 2 at idle, and the last one 3/4 throttle. This imbalance in flow will impart torsionals into the crankshaft. A million cycles or so, and things can break! That's extreme, but hopefully you see why you want airflow equalized between all cylinders. And a piece of advice, get the WEBER synchrometer with a dial and numbers on it---a Uni-Syn will choke out a cylinder if you hold it there too long. The Weber tool is actually an airflow meter, and you can leave it there forever and not affect how the engine is running. You want to synchornise the airflow at idle, and it's hard as hell to check off-idle (say 2000rpms) for proper synch with a UNi-Syn---with the Weber tool, you open another orifice and just read the number, easy peasy! Hopefully that explanation why you need both CFM and AFR to be matched.

The open-loop/closed loop situation is borderline. Like I said, the 160 will not be fully open till 170, and that is near close to remove the cold start (or open loop) situation on most cars. ECU variations, or even resistance in the harness can skew this. On a car with a standalone, you program accordingly. Thermal performance of the coolant system works on heat rejection. I would have to see the car run cooler on a 195 t-stat and run some instrumentation on it to understand what is going on in the supercharged scenario. That just sounds strange to me. On the car with the MAF going to open loop a simple resistor would have solved his problem with the ECU switching to open loop. And disconnecting the MAF Water Jacket (I believe) is screwing with the bypass circuit within the block...making for longer warmups due to no internal water recirculation while the thermostat is closed after initial start. Having an air temperature sensor bad didn't help either... As well as the reflashed EPROM... and O2 Sensor conflict sending the car to open loop regardless of what temperature it's operating... There was FAR more problems on that car than a 160 degree thermostat. Like I stated before, the Nissan ECU's look for just over 170 degrees. In worldwide applications a 'tropical' thermostat is 72C...

An L20A with only 1998CC's for Six Cylinders also doesn't draw a lot of air---even quite abit less than the BBC. Best bet for these kind of setups is a balance tube distributed IAC or Idle Air Bypass Screw. Idle is accomplished at closed throttle (with proper t-plate angle at idle, not 90 Deg but offset so as to preclude sticking in the bored or coming back past center) On the Bonneville car, we use an ECU-Driven IAC for idle speed control, and the throttle butterflies (45mm diameter) are totally closed. Synchronisation is done off-idle by linkage length, with a coarse setup to start being a check against the WOT Stop.

Correction: Slack-Jawed Shade-Tree Gomers think you're an idiot. People who understand casting, and people who have had prefessional schooling in Automotive Technology will understand exactly what they are when you say 'core plugs'. "Freeze Plugs" is a misnomer based on someone making the anecdotal observation that sometimes those plugs will pop out of the coolant in happens to freeze. Think about this: that ice expands throughout the whole jacket---I have seen PLENTY of cracked blocks where NOT ONE PLUG WAS DISPLACED! The plugs are there for the purpose of removing casting sand, providing access to something during machining, or (As the correct name suggests) holding cores in place during casting. If they are 'freeze plugs' then why are they on the back of a Nissan Intake Manifold? Reason: They need a hole there to support the CORE of the plenum while casting it! Core Plugs, Soft Plugs, Welsh Plugs. I can give you a reason catagorically why those are a correct terminology based on engineering facts. I can show you countless reasons through failures why they are not 'Freeze Plugs'... Urban Legend and Gomer Myth, perpetuated by the uninformed and uneducated---if it seems like everybody is looking at you like an idiot, take the time to educate them---ignorance is a terrible thing to leave unrectified. If they argue, consider the thought you may not be getting great service buying stuff there...

nah, unless you are using honkin' injectors and notice big pulsations in fuel line pressure, it's not a big deal.

RC 1000CC Bosch Standard 14mm O-Ring Injectors.

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!

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.

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.

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.

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

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...

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.

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).

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?

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.

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

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.

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...

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!

"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! :^)