Tony D

Don't make the mistake thinking that lightening the harmonic dampner will do anything to accelerate your engine faster! All you will do is induce a torsional imbalance into the crankshaft. The way they function is that a HEAVY ring dampens the power pulses. You get a lighter wheel, and the accelerative forces are not as well dampened. The reason it's so heavy is because it's so close to the centerline of the rotating mass, if you increase the diameter of the harmonic dampener, you can get by with a lighter ring for dampening. Same as the flywheel, nothing is free. Like on the flywheel you want your weight behind the clutch frictional area (ideally the 225mm, but I won't open that can of worms), and you want the inertia ring gone. As long as the weight of the flywheel at the frictional surface equals the weight of the dampener at it's outer diameter, you will have perfectly balanced torsionals on each end of the crankshaft. Gene Berg started selling a 7# damper for VW's. Nobody thought it could be used without affecting the acceleration of the engine, considering they usually ran a 9# Flywheel. Yet cranks fitted with the Berg "Equalizer" lived longer without breaking, and accelerated just as fast as those without. Underdrive your pulleys, but don't cut down your damper weight.

Eventually with cam changes, that same engine was dynoed up as high as 315 to the rear wheels just below 8300rpms. Blowing by like an SOB with .080" scores in the cylinders. It was non-stroker. But it's not a streetable engine by any stretch. Though with the EFI it was a seriously low idler compared to carbs. That was L28 bored 0.040"... The 2L is a bit disapointing, as it is only around 11:1, and is only making 195-205HP to the rear wheels....at 8780 rpm. Exact same head we used on the L28, huge combustion chambers hence the lower compression. The engine is pretty much useless below 6000 rpm. After that it pulls decently. We were hoping for 1/3 less HP from the engine, so the difference between 14.5:1 and roughly 11:1 is around 8% (if it was making power at the same rate as a 320HP engine, it should be around 211HP instead of 195...) So that could be attributed to the lower compression as everything else is the same. We were hoping for around 215HP, so we may do a head specific to the L20A in this off season, either E30 or E31 with welded chambers. Equivalent CR as the 2.8 engine, and maybe some other tricks thrown in for friction reduction in the smaller, higher-revving engine. With the strokers, I makes sense to me that they will make more power at lower rpms, with more useable torque band. A turbo would really help in 'useable HP and torque'---it's interesting to watch the dyno numbers on JeffP's engine develop as any throttle opening at almost any rpm produces 2-3psi of 'scavenging' boost...and MAN does that bump the torque up! Even at 1700-2000 rpms. Incidentally, the Mustang Dyno has some really nice documentation regarding back-calculating power read on their dyno to SAE specs. Their operations manual is available for download as a PDF online, and it really explains how their dyno works. Made interpreting what I was seeing during a run much more relevant. I could look for peaks in the performance, backcalculate where they occurred, and then to relay them to Jeff for AFR or other corrections. I have noticed the Dynojets differ significantly from what the Mustag gives as readings. And since we have background stored on both dynos, comparison seems to be closer on the Mustang with their software package as well. Neither dyno particularly likes a waste-spark system either...

Beware, those over 40 are not to be trusted, youngster! LOL You made it another year coser to the Reaper! WOO HOO! Cheery Sod, ain't I? ;^P

Just remember for that kind of setup to work, the throttle plates must be cracked open slightly just like on an early carburettor setup to allow air/fuel mix to make it to the intake tract... Having them behind the butterflies allows idle air to be controlled by a single point screw...which is easier as then you only have to synch the multiple butterflies for mechanical phasing, as airflow should follow identically oriented throttle blades. Though aside from synching the idle airflow, an IAC can still be used for additional air for cold startup and A/C idle-up if needed. On an aside though, if you have something like a Mikuini Manifold where the airflow is almost straight down after the throttle plates, many of the ITB setups with injectors after the throttle plates will be shooing 'down' the manifold instead of at the opposite wall at a 45 degree angle. Combine this with the high-velocity air coming across the throttle plates at partial throttle openings and you can see that right behind the plates can, depending on the manifold, not necessarily be all that bad.

They ALL had fuel pump cutoff in case the engine stalled: Earlier Versions had a set of contacts in the AFM that would enable/disable the fuel pump. Later Versions had a contact inside the Oil Pressure Swtich that would enable/disable the fuel pump. It is a FMVSS requirement. The inertia switch can be a PITA because it shuts off the engine on a bump and you have to reset it. Ford Tempos were notorious for getting bumped in parking lots and being rendered inoperable till someone came out to reset the switch (which was in the trunk!) The Rangers were mounted on the passengers floor under the carpet---really accessible places to have to go and reset your car. On the Tempos, you would play 'bumper cars' with Rentals: Bump the co-worker in front of you hard enough to stall him, but not hard enough to damage the 5mph bumpers permanently...which is all the bump you needed to disable the car. I prefer the stalled engine shutoff, myself...

Oh, the humanities!

With a couple of Resistors you can 'dummy up' a signal to the ECU and run until you get the money for the replacement sensor. Forget the curve, but you want resistance equal to a 180F temperature. The engine will be kind of hard to start and will run rough till it's warmed up, but in Puerto Rico, that shouldn't be too long! I know during the summer my CLT on the Megasquirt will show 120 if I go to the car after it was sitting in the sun all day and I go out to take a run after work! Not much 'warmup enrichment' needed when the engine is 3/4 of the way warmed up just sitting in the sun!

Niiiice! 'ONLY' 0.4 more to call it a 10 second car...LOL That trap/time/weight combo when plugged into the online calculators comes up with right around the HP you were shooting for...congratulations!

The only way to know is to install them, and then do a mockup where you rotate the cam through full lift and see if the valves hit the block...clay the area to see clearance. Don't need a crank in it, all you need is the assembled head and a block with your bore---look from underneath if you please!

Are you guys SUUUUUURE????? Take a look at the Dashpot Covers, Float Bowl Covers, Rubber Balance Line between the carbs, as well as the linkage between those carburettors. Mayhaps they be SU HS-6's! Methinks they are real SU's and not a Hitachi-Licensed copy from a Datsun!!!

Big Valves on a stock bore doesn't do a lot because in many cases the bore side shrouds the valve inhibiting flow. Dave Rebello has been doing extensive research on stock sized valves and has them flowing pretty well...in many cases in a stock bore close to what many of the slightly oversized valves will! Really though, 1.5mm Radially should not make that much of a deal with head gasket sealing...though overboring would unshroud the valve quite a bit! (Think L28 Valves in L24 Bore). You may be looking at another set of valves in stock size just to make it fly without eyebrowing the top of the block. You can always run the 90mm bore head gasket, and eyebrow the block heavily down to near where the first compression ring runs. If you saw what we did to fit that E88 Big Valve Head onto the L20A bore block we are currently running in the Bonneville Car...

An Advert, but has good Toyota Links attached: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260169081178 This article claims Toyota's First Dry Sump: http://www.scionlife.com/forums/viewtopic.php?t=108454&start=0

There is no 'drivability' issues from having your injectors in the throats of the air horns! Key is to have the injectors impinge on the wall at about a 5 degree angle just before the throttle plate. That is what Ford Testing showed. Of course, backfire issues keep them from doing this on most current Port-Injected engines. Anybody remember the HO 5-Liters tendency to immolate because of pooled fuel due to an ECU issue? They used two standard Bosch 45# injectors on their TBI setups... But I digress. Your drivability will be fine with the injectors further away. What the injectors do close to the intake valve is improve low-speed emissions through the vaporization of the petrol when it hits the back of the valve. If you go to the TWM Induction site, you will see now they have standalone supplementary rails that allow fueling from the ITB Throat/Airhorn area now for most of their setups. It makes more power, but most OEMs will keep injection between the closed throttle plate and the intake valve for that backfire safety factor. Practically speaking with a backfire and the injector out in the air horn you can have a bad situation happen if you don't immediately open the throttles to 'suck the fire out'---which is kind of counter intuitive for most drivers. Of course if you are in a properly designed metallic airbox, you can greatly mitigate the backflash issue. This all assumes N/A. On turbos airflow may dictate that you keep each injector somewhere in each respective runner simply to keep fuel from being blown off course. Many JDM apps had injectors mounted in the firewall side of the plenum shooting down the runners for the L-Engine---but I'm thinking they had a diffuser at the entrance of the plenum to keep velocity air from blowing straight across the fuel streams. HKS is good for making something that looks like it blows straight into a plenum, but in reality goes within a concealed chamber and is passed out into the main plenum through a complex diffuser setup.

A remote oil filter is a far cry from a Dry Sump! There are several combination of Wet-Sump systems available for the Nissan L that use external oil pickup from the oil pan, remote filtration, cooling, and entry to the former oil filter location on the side of the block. They are still using the sump to store oil and engine to drive the oil pump internally. Generally Dry Sumps store their oil in an External Tank, with a conical bottom to allow constant flooding of the oil pump with oil regardless of cornering G's (or for that matter in the case of aircraft, which way is 'up'!) ensuring the engine will run with an uninterrupted oil supply. Generally the pump is mounted externally from the engine, with the OEM pump being blanked off. The pump will have several stages of suction that will evacuate the engine crankcase of slung-off and used oil, and then pump it to a de-aeration tank (which may be the same as the holding tank). From there it goes to the main pumping section, then off to filtration-cooling-engine uses. Some of the stages may be dedicated to turbocharger oil supply separate from the engine supply. In any case, I'm highly doubting the Previa has one. I'm getting some feedback from my Toyota Buds that it doesn't as well, and that TRD offers a Dry Sump for the engine in their competition parts catalog. So if they are offering it as an aftermarket setup, then it's probably not got one OEM. That's my update on the Previa Engine Situation...

It goes back to having undercar integrity. No matter what exhaust system you have on there, if you have holes in your undercarrige from lack of maintenance, corrosion, etc, you are at risk. If you have a standard tailpipe exit, add any sort of rear hatch or light gasket seal to that list of possibilities. By exiting at the rocker panel, you eliminate a complete set of intrusion possibilities. There's no should or maybe about it. Directly under the car? Doubtful anything would be coming in the rear gaskets as well, leaving undercarrige integrity as the only issue to be addressed. Unless you are stopped in traffic for extended periods...and then, your neighbors on the road will contribute to your toxic in-cab environment as much as your own exhaust will. Safety Inspections have been proven to do absolutely nothing statistically for decreasing mechanically-related accidents. Emissions Inspections, on the other hand have been proven to decrease pollutants measured in the controlled area. You are better off with Vehicle Emissions Inspections than Vehicle Safety Inspections...and in this case the same could be said.

Percussion works a lot better if it's heated red hot...then it goes like butter if you slip a small pipe over the end and grip it on the pivot point in the vice. That's how I did mine!

Buck up and make three passes, dude! Then you will know what you have on the monster frankenmotor... Airflow is limited by your Z32 Turbos, whatever the guys on the Z32's have seen maxing out airflow wise will probably be near your maximum. Then it's a port flow comparison between Z32/KA/L that will tell you loads. Do you have the adjustable gears on your cams? If so, you may be able to tweak the camshafts for optimim usage with what you have. Otherwise, more lift and depending on how the engine is pulling now slightly more duration and you will have a real puller on your hands. Stock on a Neo RB25DET was in the 250 HP range, more or less depending on year. That was at .5 Bar if I recall (around 5-7 psi). Wheel HP was slightly less, but easily back up to that by the time you bumped the boost a bit. I don't know that KJ ever took his 71 down to get the results on his 3.0L RB Conversion dynoed. Even in 2.5 Guise, it was a stout runner with a single turbo!

Your shifter lever is either in backwards, or you are using the ZX one... use the original 4 speed shifter, and it will move back to the center of the shifter hole. Or take the straight shifter you have, and heat it with a torch and bend it so it resembles the 4 speed shifter you removed. The later ZX trannies have a shifter lever that has a radically different bend to it than the earlier cars. You either need the earlier lever installed, or to bend the later shifter lever so it fits correctly. It's exactly what Globerunner said. It's the shifter bends, not the placement of the tranny. The levers are different. Someone just used the later shifter lever in an early car. Bend it, no biggie.

Bob Heckendorf just finished shortening his axle shaft 0.500" on a lathe after I linked him to some Bonneville guys who shortened their shafts much shorter for use in a Streamliner. If you are really concerned about the compression binding, you can shorten the inner axle shaft on a lathe using carbide bits, but the interrupted cut, combined with lack of good old White Lead for lubrication makes for a busy day changing chipped cutter bits. Bob's inner axle shafts look OEM now, just 1/2" shorter. This is for a 280Z that he is doing a V8 Conversion on, and which is lowered so the binding issue...even axle installation was difficult. Now it's like a normal height installation, and limit straps are in place for droop. He mentioned that at this point of shortening, the spacer near the inner circlip needs to be recut and fit to the new length so the spacers and drive dowels don't go where they're not supposed to be during full droop. This may be a bit of paranoia on his part, but better safe that sorry. I don't know if he took any photos during the process, I'll e-mail him and find out if anybody is interested.

Pricey minimum I see, not sold at $232... Just looking at it the seller should be able to have discerned the thing was from an early 280Z (up to 6/76). The later tanks do not have the '1/3-2/3 bulge' so pronounced. If you are looking for one in the future, that is they type of look you want. The later tanks are much 'thicker' on the 'thin' part of the tank, by about 1/3 more, about twice as thick as the tank shown in that e-bay ad is.

Sure enough there is! Midas Muffler has a big lobbying effort in states that require safety inspections! Seriously, it's more important that the car's underside not have a bunch of holes in it than the engine have a tailpipe all the way to the rear of the car. Running the stubby to the rockerpanel will clean up the airflow and result in less CO Intrusion possibilities than running an exhaust to the traditional rear exit point. Unless you are sitting in traffic unmoving for extended periods, the straight dump under the car should have no interior intrusion issues. And even then, the vehicles around you will contribute a bunch to the CO level of the ambien environment. I have a CO tag from the local Cessna Supplier (Aircraft Spruce) hanging from all my rearview mirrors ever since I bought my first Corvair and VW 30+ years ago. They don't change... but a meter? My suggestion is not to look at that meter sitting in traffic on the 5, 91, 710, 405, or 110 freeways in LA during rush hour...you WILL see it move, even if YOUR car is SHUT OFF!

An intake tube from an N/A Z31 makes for a VERY nice intake elbow to your turbo. That is what I use on my 260Z. I clearanced the left inner fender slightly, and used a torch to seal one hose barb on the Z31 inlet pipe, but it screwed right up to the stock L28ET rubber inlet boot, and fit through the radiator bulkhead---giving me the added luxury to install the Z31's inlet silencer box (kills all that nasty turbo inlet whine) as well as allowed me to use one of the BIG K&N Diamond-Shaped Z31 Inlet Filter on it. And if I ever get in a pinch, I can always get a stock Z31 Inlet Filter and stick it on there! But that plastic N/A Z31 pipe has one other advantage boys and girls: it won't trransmit engine room heat to your inlet airstream like those bling bling shiney aluminum ones will!

Head looks like raw casting, what I thought was a cut-back si-bronze vavle guide was due to camera shake blur and rust on the stock vavle guide. Looks Unported now that there is a decent photo available.

And now I show this thread to my wife...who was thinking I was insane for wanting to make a belt-driven centrifugal supercharger for the Minibike! She now realizes there is a complete subphylum of diseased individuals for which forcing more air into engines is something that they 'just do because'! What got her was the Cat Photo. She realized it was the same sled her dad has back in Michigan, and since she has run it around a bit and knows it's characteristics...and knows what the Turbo Z runs like compared to her N/A 260Z...well she put 2 and 2 together and came to the 'Diseased Sub Phylum' Conclusion. I concur, what about you, doctor? LOL

I would have to agree the $6K is a tad high, my quotes for the Corona Conversion (66 Toyota Corona with a VG 30 ET conversion...don't even ask!) were in the $2500 complete range. Riverside Muffler runs a 9" on their 240Z, and they have been running solid 9.40's at LACR for probably the last 10 years. For a dedicated drag car, you don't need the complexity of the IRS. If the car was really really really light you may get away with it, but even in Japan in the late 80's they had converted to 9" Rears to get reliability on the Drag ZX's. Though many cars ran the IRS well into the 10's...that being said, they also had an almost unlimited supply of spares as well. Piles of broken Axle Components were a common sight at Fuji Raceway at days' end.