Tony D

You paint that over black paint which has already been buffed and polished! Just skip the superfine metallic chrome overlay and you have a killer gloss black paint job. Application of that stuff is not as one would normally expect!

Well, being they employ 'flatshift' technology that retards the spark, and gives full fuel to turn the turbo into a gas turbine on full boost, the control scenario would be to blow off the pressure to atmosphere to keep minimum flows stabilized on the compressor side. This is exactly the same as a comercial compressor. These turbos during shifting and drop-throttle are not operating as conventional turbochargers but rather gas turbine compressors. They will make boost with no throttle opening, or WOT staging at the line on a rev limiter. In that instant, to keep turbine speed up when running your EGT's skyhigh, you need to dump the pressure overboard as the engine simply can't process it. It's a totally different dynamic than drop-throttle in a street-driven car. In that instance, you have no motive force on the turbine side---and you begin coastdown. By dumping pressure you minimize the coastdown, and if you give that brief pressurized 'boof!' of air into the compressor side when there is no pressure load on it, you spin it up to speed thereby minimizing coastdown effects. Also, keep in mind the big flames from the WRC cars...when a team mechanical engineer in charge of fuel systems was asked by a design engineer for a Rally Rag 'why do they do that' sheepishly the engineer for the WRC team admitted they indeed could make the cars run without the big flames, but 'the fans love it, and it makes for startling sponsorship photos, so we go full rich (instead of fuel cut) on drop-throttle for the effect!' So there IS showmanship in all forms of motorsport... Most OEM's blowdown within their intake tract for metering concerns. But Porsche is one of them that uses tangential entry of that blowdown energy to actually do something positive in their turbosystems. Waste not, want-not!

I can agree with that statement, just not that it will be twice the inlet plenum pressure. In the old F1 days, the turbo sizing was enormous for the size of the engine, but for the HP they produced on mass flow, it wasn't so big. And they had very low preturbine pressures compared to inlet pressures. They weren't at a crossover point where reversion was an issue during valve overlap at least. Yes, the pressure would be higher, but in one that is sized adequately it should be well less than 2X inlet.

I had the same experience with my L28. .43A/R on the turbine side, you can upgrade to the L28ET housing, the cartridge in the center is exactly the same (if you want to...) I would love to have one of those L20ET Turbos (or a pair of them) back...I sold mine to a guy with an Isuzu 2liter, and wish I had it back for some of my street applications. I loved auto-x'ing that car...invariably instructors would say 'I don't like turbos for auto-x because they have non-linear response' and usually before the first turn it was "this car is turbocharged? Feels more like a Supercharged car!" Love that early spool, but all-in by 5500. For an L24 it should be very nice. Cheers!

So basically, you're saying put the hole right where those chill pads are on the casting? Almost like someone was leaving a marker for people modifying the head later on, post factory? (Hint, Hint!) Hindsight is 20/20, eh? If you look in the 'how to modify' book at the electromotive turbo setup, you can see their manifolding of the water above the combustion chambers...and it looks like they sunk their holes right in those chill impressions that you have photographed so well in your closeups!

I have only the one FPR, and unfortunately for you, it's SO adjustable it works on EFI pressures as well!!! Imagine that, I paid 12,000 Yen for that thing in 1987 (and think it's around 17000 yen today from what I recently saw) and never figured out what they were talking about in the (printend in japanese) instructions about the "EFI" section, because it showed two different possible ways to set it up---after some dorking around these past 30 days of unemployed freedom has revealed, the second setup was to allow the regulator to function at a base pressure of 3 Bar, instead of the way I was formerly running it around 0.3 bar! Clever those japanese! Panzer, I didn't blow you off, I just saw it, you can PM or e-mail me any time. Sorry I didn't see this post earlier. The inlet pipe I have is on the front cover of the SK Comp Turbo Plenum I have---the P.O. welded it on in a sort of 'HKS Hybrid Inlet Setup' sort of way...

Your car will be in very good hands, Ad is an artist!

At idle, the L will survive in stock form for a looooooong time with only 3 to 5 psi at stock idle speed of 750rpm. The stock gauge will not even read that low! This is not a Chevy where you have 43psi at idle...

The cumulative "They".... It was always funny to watch guys explain 'Mitsubishi' to other gaijin (not that I'm not one...) as 'see, they made the Zeroes during WWII, and that heritage shows through:see the three spinning propeller blades in their logo!' Of course, Mitsubishi means 'Three Diamonds'---which is what their logo is, and if you ever looked closely at the belts on a Mitsubishi you would see they use Mitsuboshi Belts...the logo on the belts being Three Squares, and Mitsuboshi meaning 'Three Squares'...

No, you will pinwheel the compressor. Trust me on this one! Industrial compressors will viod the warranty if you do not install a check valve on the discharge because as easily as they will spin with power to the gearbox, that same pressure will stop them dead and then spin that same 15,000 HP motor in reverse just as quick as you can say 'what's that noise?'! Same goes for automotive turbos, especially ball bearing units. You will not be equalizing volumes and blowing out the air filter, you will be imparting pressurized air to the suction side of the wheel which is under several inches of water vacuum. This is exactly how Porsche does it. I guess they aren't high-end? In any case, with the turbine already spinning, blowing a pressurized air source at it in the correct orientation will pre-spin it briefly to a higher rpm. It will continue to coast down as normal if still off the throttle, but if you reapply throttle the turbine is closer to productive rpms in this case. Try aiming the nozzle wrong and see what happens. You will (if you have a turbo tachometer with a datalogger) see a marked decrease in speed when that air hits the wheel. As the 'twice the pressure' in the exhaust, I know for a fact that JeffP had 20 psi in the exhaust when there was 20psi in the intake plenum, under load, at 7000rpms. Some of the 'book stuff' really is so out of date it isn't funny. Proper turbine A/R sizing and current technology will make for radically different exhaust pressures that even experienced as recently as the 1980's

I don't know the tie-in, but "Japan-Cupid" is the banner ad on the bottom of this page right now...methinks Mr. Coffee has been browsing the JDM prawn sites and it's come home to roost! Large write up on the "G-Nose" in the Aerodynamics forum...

THREE-ZERO San = Three Maru = Zero Also Mitsu as in Hitatsu, Futatsu, Mittsu, Yottsu as opposed to Ichi, Ni, San, Shi... Like they say: "There can be several ways of saying the same thing" Yon San Ni would be '432' as in Z432...wakarimasuka?

73 SU's have a larger float bowl than the 74's do. The front side (air cleaner side) of the float bowl is 'flatter'---the 74's have a lot of inclusions into the bowl to minimize fuel volume so when it boils out after shutdown, it doesn't flood the engine nearly so bad... PM me if you want me to send you some $$$...LOL!

The only caveat with letting the electric pump cool down the block after it's run hard is the possibility of cooling it too fast and with cast pistons actually locking them in the block till the temperatures equalize. Lance was yelling at Jeff on the dyno for doing this. Technically correct...but geeze, let it post cool to some degree! Our compressors circulate oil and coolant for 30 minutes minimum after a hot shutdown. When in R&D it was interesting to watch instrumented bearings show the temperature spiking to levels nobody thought possible from a simple normal shutdown. Temperature goes into the bearings for quite some time after shutdown. From what I saw, it seemed much more important to keep oil flowing (and let it's sump capacity act as a reservoir for the heat it takes out of the bearings) than circulation of water after shutdown. And a standalone oil pump wouldn't cool your block before the pistons...making Lance happy! (even with those cool SR20 style oil squirters for cooling the pistons...you'ld cool the pistons more than the block, increasing clearances circulating oil after shutdown!) There I go again, 'thinking'! LOL

Is the manifold sent in the stock US/JDM spec manifold, or the vastly superior European Spec manifold? The Eurospec Manifold has internal passages that are at least 1 5/8" diameter in the log section (larger than the O.D of the SFP header group buy of several years ago). It does come in three sections, that can be joined by a manifold connector available at the Mercedes Dealerships Worldwide (thanks JeffP for that legwork)... Adding an external wastegate to that manifold should easily support 600+HP flow-wise, and if you 'thickened' the stock flange mounting area by 1/2" that would make the clearance similar to the stock one with the 1/2" spacer everybody seems to add to them to get the compressor clearance with the larger scrolls.

Your oil pressure is fine. I replied to your other post as well. Mechanical Gauges only for diagnosis. Do not trust the dash gauge.

"Tony, you mentioned difficulty in replacing the stock pump." Did I? 10psi at 1000rpm, roughly 10 psi per 1000 rpm means 3-5psi at idle speed of 500 is fine, over 3000rpms, pressure usually above 45-60psi. Verify with mechanical gauge. That's all I can find. Nothing about difficulty replacing the stock pump, just that generally it's not necessary. These cars are NOTORIOUS for bad sender units on the stock oil gauges, don't believe anything the stock gauge says. Use a REAL gauge with a large-bore tube to monitor pressures when making decisions on oiling systems. "Bearing Clearance" is a function of engine builder preference as well. There are many people who use high-flow pumps and larger bearing clearances for horsepower and safety margin. I know people who were told their engine bearings 'were shot' and needed replacing who simply upgraded to the Turbo-Auto Pump (higher flow) which moved oil pressure higher than it was....and that was over 100K miles ago (over 450K on the engine now!!!) Yeah, they probably did have excessive clearances, but you want to talk about an engine that revs freely...and as long as there's enough oil flow to keep the wedge intact in the bearings you should not have a problem...

What Year Flat-Tops... I have been paying shipping to harvest sets from those discarding them. My preference is for 73's... Though 74's will do. It helps if the linkage between the carbs is included.

#1 being close to the pump with the highest pressure available should flow well with a thermostat at the back of the head... And you always have the internal bypass there back to the inlet---likely that would have to be restricted, and 'external' bypasses be added back to the inlet of the pump from the #6 end of the head. Adding flow to the #1 cylinder in this instance would be easy, since you already have a thermostat housing that is blocked off with a plate, right? LOL

"Earlier in this post you mention that the block of flow from the rear of the head when the heater core mixing valve is closed caused all of the overheating problems in early 240Zs. " I never said that, I said looping the hose from the head to the inlet causing a shunt will cause overheating. The stagnation of flow above the combustion chamber on 5 & 6 is there regardless of heater operation. If the heater is on, chances are really good you aren't in what would be termed 'extreme overheating environmental conditions'. Somehow people think they need that flow out of the back of the head when they remove the heater from use. This is not the case. In normal operation, that petcock at the rear of the head is closed. People have to realize that---for some reason they don't. Plugging it does nothing more detrimental than driving around with your heater 'off'. But looping it, that causes the shunt. The only conditions where that shunt should exist are the conditions previously mentioned about cold-drive off and ultra-high rpm operation before warmup. This is why the supplemental bypass poppett valve was added to the ZX. If someone MUST loop that hose, I'd not do it unless that ZX Poppett valve is in the line. Then it will stay closed during warmup, and ONLY open the shunt during higher revs when the thermostat on the outlet of the block is closed and can't provide sufficient flow to prevent cavitation of the pump from operating below it's minimum flow curve. The safest thing to do is plug the head, and simply let your engine properly warm up before running to 6KRPM... *************** As to routing it to the T-Stat Housing...I don't think that will help the situation. I think that will exacerbate the stagnation of flow above the #5&6 head combustion chambers, this petcock will be taking block waterflow and shunting it around that upper area in the head. This is why tapping the head above the combustion chambers and routing it to the T-Stat housing helps the situation, it allows the block flow to go to the top of the head and exit directly.

Guilty. Pegged my tach in my 75 Fairlady Z on a stupid downshift, plastic fan bent the tips back far enough to touch the radiator and cut it... The old Ford Capris were an engine that was notorious (In the USA) for having a 'rev limiter', when in fact it was simply restrictive carburretion. You could flatfoot it, and you were lucky to get 5000rpms out of the Kent Mill. But put a Rochester 500CFM 2-Barrel on it, or the European Weber IDF induction on it, and it would twist the tach all the way 'round! We have enough induction to be bad for us in free-rev. Including the Analog EFI setups as well. I used to take L-Engines to the scrapyard to die, and we would brick the throttle and take bets on how long before it went 'boom'... Skylines mostly. An occasional Gloria and Cedric as well... They are indeed interference engines. The valves will hit. Things can go bad ranging from simply nicking the piston crowns, to a bent valve and broken Valve Guide, to a broken piston and resulting catastrophic failure. Usually float will 'bounce' the valve and nick the piston crown, likely bend the valve if it happens more than a couple of times. But if you get the timing incorrect and it's mechanically held open when that piston is coming up, things can go bad quickly. Just since we are talking about rev limits, the 'light flashes' on this one at 9500, and that's not the limit...

I have seen 'plenty' of people with a loopped heater core. And in EVERY case when I block it off properly, overheating problems go away. You can get away with a LOT on the cooling system, especially in the cooler, more temperate regions of the USA and Canada. But you try that stuff in the Desert Southwest, and you will be milling overheated heads on a regular basis! That someone 'has done it that way' does not mean it's correct. Think about it logically, and you realize the system is designed for ONLY 'cooled' water to go in the water pump inlet, save for ONE small 8 to 10mm internal boring on the block. Other than the later ZX 'poppet' valve which was added for extreme circumstances, nothing is flowing through that 15mm line on the side of the block, and nothing comes through the external bypass line that has not been somewhat, if not totally cooled. The bypass line usually heats the TB, and AAR valve, and the 15mm line goes through the heater core to be cooled before re-entering the coolant pump. You use that line, you have a direct shunt---you may not see a temperature increase on the outlet...but what you have a DRAMATICALLY reduced internal block pressure due to the greatly increased flow. Add a slight heat increase in inlet temperature to a decreased pressure system and you have a recipe for nucleate boiling, and cavitation in the pump or the block perpindicular to the wrist pin... That line being blocked off completely is NOT detrimental to the engine whatsoever. Letting it recirculate uncooled---it's bad. just how bad will be determined by the condition of the rest of your system and operating environment. Lots of aerosol blocking UV and a 90 degree day in NH is better operating conditions than a 65 degree clear and sunny day in SoCal---road temperatures at the radiator will be likely 10-15 degrees higher (in the area of 104F) in SoCal, while NH will be maybe 95F.

John has a good point here, but his specific output was slightly lower than some of the engines being referred to here. Probably increasing the cap pressure would be a quick check to see if there is an improvement immediately. Only downside would be the possibility of hoses and other soft components not being up to the task long term. Nusiance leaks, etc. With a 30psi blanket pressure, in-block pressure would in essence be doubled over the stock cap pressure (or even the high-performance 16psi caps). That would keep a decent cap on the formation of the insulating steam bubbles. But it may still be necessary to increase flow to take the heat out of there. The increased pressure is a functional fix of the steam formation, but not an engineered correction of a flow deficiency in the cylinder head. Nissan recognised as much in their redesigned heads for FIA competition and the system on the LY head. They both have different cooling systems that evacuate the upper cylinder combustion chamber water along the whole legnth of the head into a separate off-head manifold, instead of making it all go back up front to come out a thermostat housing that is basically at the front of the head. I wonder..... Could you take water off the BACK of the head by spotfacing a place to make a remote thermostat housing attachment, and then simply using tubing to the radiator... That would seem to let water flow 'work properly' inside the head. As KTM mentioned, #6 has some slow velocity water, so it would evacuate out the back well, while that high-velocity water coming up the block through #1 could slow down some working it's way to the back of the head to evacuate out a rear-mounted thermostat housing. Maybe make a Corvette-Style reservoir tank at the rear of the engine bay before moving on to the radiator---giving it a 'high point' for any steam taken out of the system a point to collect before the water moves on up front to the radiator...

That's becase clean compressed air will spin a cold compressor wheel just like a pinwheel just as well, so the BOV recirculates to a tangential entry to the compressor hosusing to spin the compressor and keep the speed up. And that doesn't screw with your O2 sensor reading, either. And if you have a MAF or AFM, blowing into the inlet chamber also keeps your metering correct on drop-throttle as well. A Win-Win situation.

YES, you CAN swap in an L28ET. Search the CA DMV and SMog websites, it's a very straightforward and easy swap. I know people who have put L28ET's into MAXIMAS and gotten the BAR sticker for their door so it's all legal. Your car WILL be required to have a Catalyst, but nobody says it has to be the stock one. AFTER the catalyst (using the stock L28ET downpipe and front exhaust section) you can run whatever you want. Put a nice new high-flow 3" Catalyst in there, with the 3" exhaust back from there, and you will have a nice starting point with no problems passing smog. AFTER the cat, you are free to do about what you want. But between the turbo and the cat (which everyone here knows would benefit from the 3" downpipe---20HP on a stock L28ET) you run the risk of a 'visual fail' from a non-CARB approved item IN the emissions system. If you want it Legal, you will be saddled with the stock cast iron downpipe and stock pipe between there and the catalyst. That all being said, if you 'upgrade it' in between tests... as long as that catalyst stays on there, most roadside inspections will not likely know to tag you on it! And after that initial referee inspection, likely it will never come up again as long as you have a functioning catalyst, and a working O2 sensor. Under Cal Emissions it's pretty easy to retrofit vehicles with newer engines, most of the griping out there is done by people ignorant of the process who see a simple smog test as some insurmountable obstacle. As long as all the stock stuff is there and functioning, it passes.