Pyro

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Are you using a stock T3 exhaust turbine with your T3/T4 turbo? If so, it will not work very well with a lot of valve over lap. It is very hard to change the lobe separation angle on a regrind cam. And this is what typically makes the most difference between a turbo cam and a non-turbo cam. You will be much better off using a stock NA cam if you are using a stock T3 turbine. And Yes, the stock intake is not really designed for high rpm performance. I would consider 6500 rpm the max for a turbo setup using the stock intake. It will rev more but not ideal.

A stage 3 cam will not work well with a stock turbine. A lot of back pressure caused by a restrictive turbine along with a lot of valve overlap is a bad combo.

You are using stock dished pistons, right? First, I would install a stock P79 or P90 head on your current block. This will lower the compression to 7.4:1 cr and give engine a better turbo cam. At least put in a stock NA cam. You can turbo charge the stock 8.3:1 cr setup (N42/N47) but ignition timing will need to be lower. Then find a stock t3 turbo with wastgate, j-pipe, downpipe, exhaust manifold, and turbo oil pan. What you need for the fuel enrichment for a turbo is called a FMU, you can get one on ebay for $100.00. This little device installs in the return fuel line and will increase fuel pressure only during boost. I would get a 6 or 8:1 fmu, The engine will need around 60 psi of fuel pressure with 7 to 8 psi of boost when using stock NA injectors. 60 psi is about all a stock efi pump will make while providing enough flow. Then you need to lock the mechanical advance in the distributor and set the timing to 28-30 degrees if you use 7.4:1 cr and stock boost (7-8 psi), or 24 degrees if you use 8.3:1. The fmu with locked timing makes a decent and cheap low boost turbo setup. But plan in the future to add an aftermarket efi system with ignition timing control. You can use your current cam if you use a stage 5 T3 turbine, but the engine will not make boost until 3500 to 4000 rpms, and that is no fun in a street car. Change the cam and springs, or just install another head with a stock cam.

What part of the leg are you missing? A friend of mine was born without a left leg (from the knee down). He drove a 5 spd z for years until we recently converted it to a v8 with an automatic. Use a prosthetic leg/foot on the clutch.

I gave up on using pumps that use motors with brushes. I recommend that you use a msd efi 2200 pump with an Aeromotive return style fuel pressure regulator. I forget the aeromotive model number, but it comes with 2 springs, one for low pressure and one for high pressure. So if you ever decide to add fuel injection then all you need to do is swap the spring. I helped a buddy do this setup on his V8 powered Z. He had a carb for the last 3 years but is now adding efi.

What color smoke? White or black?

Could be detonation since you have high compression and a stock cam. Lower the timing 10 degrees and try it again. If that fixes it, then reduce the amount of timing in the advance curve. Also, check to make sure the spark plugs are tight. I recently had the same issues and loose plugs was the problem.

There are 2 bolts to adjust the timing. One on top and there is another on bottom that is hard to see that bolts the distributor to the adjustment plate. The bottom bolt also has adjustment.

If the rings don't have enough gap then the piston will come apart like that also. And turbo engines need more end gap than NA's do. Forged pistons are not required for a turbo. And forged pistons will also break, just not as quickly as casted. A turbo setup with no ignition control will do best if you just lock out the ignition. With stock boost (7-8 psi) and 93 octane: I use 28 degrees with 7.4:1cr, 23 degrees with 8.3:1cr, or 17 degrees with 8.8:1cr. Do you have an O2 sensor in the exhaust? Even a simple 1 wire used with a volt meter will indicate the mixture on boost.

Very tight bearing clearances would cause that. Did you plasigauge the engine? I'm not sure the exact pressure the release spring comes in, but I would guess it would release by 90 psi. What is the oil pressure when the engine is hot? Try another gauge. 5w-20 would help. A standard volume oil pump would low pressure at idle.

Too much ignition timing can reduce top end power and that is where the max HP is being made. Jacking up the base timing also increases the total timing, unless you shorten the length of the advance slot. Have you performed a valve adjustment lately or had the 30 year old injectors cleaned and checked? Lots of things can reduce hp if not maintained. Trap speed at end of 1/4 mile works much better than et. Using your odometer and stop watch is very inaccurate. Get a g-tech meter or make an official run down the 1/4 mile and use trap speed for your HP calculations.

I bought steel mandrel bent j-bends from summit racing and pie cut and welded up my IC pipes. Put some welds on the pipe ends to act as hose barbs. Spray painted the outside and a light coat on the inside.

Add some meth/water injection and then more ignition timing would be possible.

FYI, Nissan rated the 75 to 80 L28 as 8.3:1 (N42 block with dished pistons and N42 or N47 head). Then 8.8:1 in 81 to 83 with the F54 block with flat tops and a P79 head. 7.4:1 for the turbo with a F54 block with dished pistons and the P90 head. Yes, the P79 and 90 have the same size chambers.

Seems about the same as we got when I helped a friend install a turbo on a 81-83 flat top L28 engine. Took only 17 degrees of timing with 8 psi of boost and 93 octane.

The wrong power valve will not stop it from starting. However, it will make it run super rich. I would use a power valve rated at 1/2 the vacuum at idle. Does it start with staring fluid? Is gas squirting out of the carb with you pump the throttle?

Make sure the ignition advance is working smoothly. If it sticks then it will cause problems like you describe. 20 initial and 36 total would be nice for your setup. Then add another 10 degrees with the vacuum advance (get an adjustable advance). I would also recommend getting a good distributor, like a msd with adjustable mechanical advance and adjustable vacuum advance. A cheap distributor will lead to problems. I like the 750 holley 3310 carb with a regular Edelbrock RPM intake (not air gap). My wife is from guadalajara. Cool town with lots of pretty girls.

The important thing is to match the head gasket to the block type. (N42 or F54). In your case a N42, which came with 75 to 80 L28's.

A little too much fuel pressure for only 5 psi of boost. But the timing seems right. I like running around 8 psi of boost with 65 psi of fuel pressure when using stock NA injectors Check the spark plugs. With the engine running, Pull the vacuum line to the stock fuel pressure regulator to see it any fuel comes out. Also pinch the return fuel line with the line off to see if fuel comes out.

No problems with my felpros. Even on turbo or high compression applications. Flat head and a proper job is what counts the most.

Lots of things can cause that. For example. Mine has done that a few times over the years. One time is was loose spark plugs and the other time was a leak in the fuel pressure regulator which dump extra gas into the intake from the vacuum port hose. I'm sure there are other things to check. Like a bad air flow meter or weak ignition (no name a few). Good luck finding that.

Check the piston deck height. You will notice the piston sticks out of the block around 0.010" which will bring compression up to 8.8:1 with a 0.040" head gasket. The L series engine is prone to detonate. Yes, you can add a turbo to the 8.8:1 setup but can not run much boost or timing with a stock cam. When I did it, could only run 17 degrees of total timing on stock boost (7 to 8 psi). You will make much more power with a 7.4;1 cr setup (stock turbo cr) and more boost and timing. In any case, use a NA cam.

You need to open up the distributor to get to the mechanical advance slots and springs. Pull off the rotor, Pry off the star on top, pull the top plate, then you can see the springs and slots. Then you could take the springs off and use wire in their place, and maybe some rtv to fill in the advance slots. Set the timing at idle to 24 degrees. Use 7 psi of boost with 60 to 65 psi of fuel pressure at full boost. Then use the vacuum advance part of the distributor like normal. The boost will shut down the vacuum advance. Should be able to hit 100 in the 1/4 mile with 7 to 8 psi of boost and intercooler.

I'm using totally stock 76 efi and ignition. That includes the smaller NA injectors. No wait, that isn't totally true. I recent changed the stock fuel pressure regulator out for a Aeromotive fpr because the stock one starting leaking fuel, but I use stock fuel pressure. The throttle body isn't the bottle neck. It is the small intake ports. stock of 60mm TD doesn't make a difference. I'm using 2-1/2 exhaust with 2 inch from the turbo to the intercooler then 2-1/2 from the IC to the throttle body. My car had a 110 mph trap speed in the 1/4 mile. Yes, lock your timing at 24 btdc. Locked means it doesn't move when you rev it up (without the vacuum advance connected). But use the vacuum advance as you would normally.