240260280z

$15 and worth it: http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Remote-Starter-Switch/_/N-25eo but I made mine from a $5 Volkswagen horn and spare wire and spare connectors.

Interesting read on popular hotrodding.com: source:http://www.popularhotrodding.com/tech/0611phr_the_secret_life_of_carburetors/index.html The Accelerator Pump Under idle and cruise, a considerable amount of vacuum exists in the intake. This vacuum reduces the boiling point of the fuel, causing it to vaporize much easier under the prevailing high vacuum conditions than under low vacuum. This useful characteristic helps fuel distribution considerably during idle and cruise. When running down the freeway at 2,000 to 3,000 rpm with 15 inches of vacuum, a lot of fuel being drawn into the engine is vaporized well before it reaches the cylinders. Standing on the gas pedal completely changes the situation. When the vacuum transitions rapidly from a high value to near zero, fuel held in vapor form now condenses into liquid onto the manifold walls. Although a fresh charge of air is entering the engine and carrying its associated fuel, the engine, for a moment, still goes very lean. This is due to the fuel that was contained in the air suddenly clinging to the manifold walls, and for a moment at least, going nowhere. This causes an enormous flat spot that the engine simply will not drive through. To offset fuel condensing on the walls, an accelerator pump system is added. This squirts additional fuel into the intake to cover the would-be hole. A basic schematic of a typical pump system is shown in Fig 11 (see p. 91). In this example, a piston is shown injecting the fuel, but most often, the function of the piston is carried out by a spring-loaded diaphragm such as in a typical Holley carburetor. Calibration of the accelerator pump system is carried out by jets to control the rate at which it goes in; various springs, cams, and diaphragm sizes are used to control the amount that is injected and the duration of the injection phase.

I found this on Zcar.com. It matched my interpretation of the drawing of the power valve on paper but exploration of the air and fuel lines is critical to understanding its function. My thinking is that during a throttle-up transient, the spring unloads and squirts fuel into the air stream as opposed to being to be sucked into it.... but I have no details of the control circuit yet....but I bet you are correct with the vacuum threshold I should have brought my mighty vac yesterday.

Dang that fuel bowl reminds me of a weber! Could you do me a favour and post the volume/capacity of the flat top and round top carbs if you have a chance? That would be good info to float (pun) on the net for racers.

Thanks! my friend "Cptn Obvious" on this forum, is a superb investigator and data gatherer with great attention to detail. Plus "he has a lathe" (in joke). I know he addressed removing the jet by making a special tool, and also returning the jet to correct depth by another special tool but I do not know if he addressed the dreaded stuck needle. I would guess he would make a custom clamping tool like the one he made for removing the nozzle (in photo below) that grabbed the needle at the shoulder (in the groove). Some threaded holes in the clamp could be used to turn bolts that pulled the needle out in a similar fashion to the threaded holes in brake drums and pulleys that help removal. Heck a few holes in his jet clamp could turn it into a dual function tool! Thanks for the Brasso tip. Now I need to get me a set of flat tops to work in parallel with the Guru! Did I mention that he has a lathe?

The 5th fusible link (For the EFI System) is at the +pos battery lead where it connects to the battery post. It can come unplugged easily. It is labeled "EFI Power connector" by the fool who made this drawing:

We will find out.... with data over the next month or two.... Tony D already knows. I presently am planning a "diluting circuit" for a round top to make it a 2 stage carb... an accelerator circuit would just be needed to make it 3....thinking on that now. The fact the 2nd gen also draws fuel lower in the throat (like a British racing mod), it has a narrower throat (like Mikuni bike CV ), a big fuel bowl sits right under the bridge, and the fact its bridge geometry is much different means that it was changed for either performance, fuel efficiency, emissions, reduced manufacturing costs, or a combination. As mentioned, exploration, data gathering and comparisons are needed. There are many other interesting differences that will be shared too. Remember that Nissan engineers seemed to always fight emissions performance losses that hurt the base L24 building block by increasing horse power (stroke & bore) so it is reasonable to assume they also looked elsewhere for improvements. Probably heard in the halls of Nissan HQ in the early 70's: Engineer "The !$^& US pollution and safety regulations are turning the car into a fat lazy pig." Bean Counter "If the power disappears, the customers will disappear and we will disappear." Boss "Work the problem and give me solutions."

Weird, let me see if I can fix. How is that now?

I missed the fact the this forum does not convert file names to numbers... you hit it out of the park Yup it is a flat top jet that is normally well secured deep inside a flat top SU. It only sees light through the fuel bowl window. My new Z friend showed me a great deal of flat-top details today including a cool tool he made to safely remove the jet,

Sir: Strike 1

Top view looking down piston bore (flat top is on right) Flat top: Bridge is wider (front to back). Jet sleeve is fixed and jet depth is set to correct height in factory (no choke up/down movement). Front and rear ramps are different geometry. Piston diameter is smaller Has 3 circuits Main (jet and needle like in a round top) Choke (see the small forward spraying nozzle upstream of main jet) Power Valve (off idle transient to WOT...see the hole on right side of ramp at back of bridge) Has air bypass around main jet for setting idle mixture. Has integrated fuel bowl below jet. Front view looking into throat (flat top is on right) Flat top: Bridge is lower in throat. No stepped edge on front of bridge. It blends into ramp. Choke nozzle is seen in foreground in front of main jet protruding from the floor. Floor of throat from front of carb blends into ramp. Choke valve (in open position) is seen in foreground near top. Tube bringing ambient air to push up on piston is seen in foreground on right. Rear view looking into carb (flat top is on right) Flat top: Bridge is lower in throat. Higher vertical dropping edge "cliff" at back of bridge Narrower vertical dropping edge Rear edge of bridge is further back in carb and closer to throttle valve Power valve fuel outlet is seen as hole on lower right of photo below the bridge level. Idle air outlet is as hole on middle right of photo above the PV fuel outlet. Bushing for throttle valve (removed) is seen on side wall of throat

Made a new Z friend only 45mi away in Pa. Had a very nice drive through beautiful Pa. and lunch. Spent the day talking carbs and geek stuff... a blast! Learned a lot. Also planning research collaborations too. Stay tuned to this channel. P.S. How many of you have ever seen this item that rarely sees the light of day except through a window? Tony D you are not allowed to comment

Thanks a million guys! Gee Dan and Jim wow thanks! Yes I'll gladly take two... I'll pester Jim and he is a long time buddy. I'll pm you. Philip

http://atlanticz.ca/zclub/techtips/suspension/frontcontrolarm/index.html

There is one you can get from Autozone that is supposed to work with minor mods. I have one but never had a chance to try it. http://www.autozone.com/autozone/parts/Mighty-Lift-Support-Lifts/1971-Nissan-Datsun-240Z/_/N-iq2l9Z8ii2g?counter=0&filterByKeyWord=hatch+strut&fromString=search&itemIdentifier=193495_3214_2819_

The weathermen missed it.... it was not the wind but rather the rain that caused the problems. The media was in NYC and along the coast waiting for the wind and hyping fear when at the same 100 to 200 miles inland, the deluge that all missed except the poor folks hit by it without warning.... shame on the meteorologists and press.... they missed it completely.

Bridge removed to enlarge opening and brass "wing" positioned as a substitute.

Triple SU's

Draw-through with extra fuel bowl.

Norm's famous "tosser" mod

note the epoxied gentle ramp leading to the bridge that still keeps the "step" for turbulence.

It has a DC output for logging. I am not sure of the sampling rate, hysteresis or DtoA details but can find out. I am playing with this AtoD to make a flow bench. We can talk about it on Monday http://www.vellemanusa.com/us/enu/product/view/?id=500349

I'l like to put new grommets in the 71 240z I am restoring. Any suggestions? What is hole size? (I am thinking this may work):http://www.datsunparts.com/2371

http://www.circletrack.com/enginetech/ctrp_0309_race_engine_airflow/viewall.html