Pyro

My T04B-h3 with a T3 stage III turbine with a stage 1 MSA turbo cam will get full boost (12 to 14 psi) by 3500 rpm in all 5 gears using a 3.90 diff. I found that low ignition timing and/or a rich mixture will slow down the boost application in first and second gear.

Another thing to consider is efi pumps don't like making 55 psi all the time. A pump must work much harder to make 55psi as compared to 30psi. A 1:1 boost referenced regulator will keep the pressure consistant across the injector and will be easier on your fuel pump during off boost driving. Areomotive makes a nice one (summit racing, 135.00, AEI-13109). If you don't use a 1:1 pressure regulator, the injector will not flow as much during boost. For example if the fuel pressure is 40 psi and the boost is 40 psi there will be no flow at all from the injector. Of course this would never happen but you get the idea. Go to RC Engineering. There are some formulas to figure injector flow at different pressures. Here is one formula: (((new pressure/old pressure)**1/2) x old flow rate). So if an injector flows 550cc at 40 psi then it would only flow 435cc at 25 psi (40 psi fuel pressure-15 psi of boost).

Did the same thing on mine but I have an external wastegate. I didn't think that would be possible with a flapper type wastegate, but that is good to know that it works on internal waste gates also. The crack isn't a big deal. But It looks like your have a chunk of cast iron missing when looking down the wastegate hole (4th photo).

I think you need to stay with the 10.5 inch clutch for clearance issues. You need to use the 153 tooth flywheel. I use a Ram clutch and pressure plate with a 6 puck metallic pads. Summit Racing, Ram-6129, 184.60. And a Ram pressure plate (diaphragm style, 3000lbs), Summit Racing, Ram-401, 149.95. This clutch lasted a few years of drag racing behind a 362 sbc with 11:1 cr, 150shot n20, GM T5 and MT drag slicks.

28 degrees is the total advance in the distributor. It doesn't account for the initial timing which you need to add in yourself. Try 15 degree initial with 21 degrees advance for a total of 36 degrees.

Nice looking dyno. Looks likes your engine starts making decent power at 3500 and power starts falling off at 5500 to 5700. I guess those heavy springs are giving a few more rpms. However, torque is very low at 3000. A stock T3 would be about twice as high. I guess it all depends on your defination of a good match. To me, it seems like your engine would really make some serious power with a cam swap.

What is pulling boost? Full boost are starting to make boost at 3000? A T4 exhaust tubine on a 2.8L takes a certain amount of rpms to make full boost. I have seen full t4's run on completely stock turbo engines and they only make 1 psi at 3500 and full boost by 4000. If you are getting boost at 3000 with a T4 turbine then I would say your setup isn't typical and you have done a fantastic job tuning your engine. Even my little T3 housing with a higher flow turbine takes 3500 rpm before full boost and only starts to make boost at 3000. And even this was too high a rpm for the stock cam. 1500 rpms on full boost was to short for me. So I had to upgrade to a bigger cam (MSA stage 1 turbo cam) that could make power to 6000. In hindsight, I would have stayed with the stock cam and the T3 turbo since I drive the car mainly on the street. My car was much more pleasant to drive on the street with 14 psi of boost, stock cam, and stock turbo. As you can tell, I'm not a big fan of turbo lag.

I'm not talking about max power, I'm saying a T3 is a good match for the stock cam. The T3 comes on full boost as early as 2500 rpm and will pull hard to 5000. A 2500 rpm power band which is nice on the street. A straight T4 on a L28 will only start to build boost at 3500 and maybe get max boost by 4000 rpms then the cam is done by 5000. Not a good street engine with a very narrow power band. Sure, a T4 could make more peak power even with the stock cam but that isn't the only way to determine a good matched setup. Try comparing the torque and hp of a straight T3 versus a straight T4 on a L28 at from 2500 to 3500 rpm.

Flow required is engine volume and rpm dependant. Turn up the boost and shift at 5000 (not 6500). The stock turbo cam is pretty much done at 5000 rpms anyways. Plus the T3 comes on very low in the rpm range so no need to shift at high rpms. at 15 psi, 2.8 liter and 5000 rpm, you will only need 32 lbs/hr. The T3 is a good match for the stock cammed 2.8 liter Z engine up to 15 psi of boost. When bigger cams are added and higher shift points are used, the T3 will start running into a wall when used on a 2.8 liter.

Mount the regulator on the cool side of the engine compartment (passenger side). A good place would be on the firewall between the battery and the hood release so the fuel line will not be heated up by the hot air from the radiator. 4 psi is right for SU's. Get a Mallory comp70 if you want a quiet pump. I bet you have a Holley pump (loud as hell). No need for the mechanical pump.

It goes up high on the pan (near the pan rail). I did one years ago by punching a 5/8" hole and taping the hole. Punching a hole is better because it will give a lot of surface area for the tap as opposed to drilling a hole in a thin piece of material. Use the stock location if you what to use the stock turbo drain line.

try increasing fuel pressure.

You can do this an easier way. Just bolt on the following Nissan stuff on your stock 77 engine. Turbo manifolds (intake and exhaust) Stock turbo and wastegate, stock j-pipe, and stock down pipe Turbo oil pan and pickup tube and turbo drain line Turbo oil feed line and sending unit tee Then buy a FMU for 200.00 (bell engineering) and set the fuel pressure to 60 psi at 7 psi of boost (stock wastegate setting). Use the stock 77 AFM, 77 injectors, 77 ignition and set the total ignition timing to 26 degrees (with vacuum advance dis-connected). Reconnect the vacuum advance after you time it. You will also need to make a connection between the turbo inlet and the AFM. That is it. No crank sensors, no programming, but you will be limited to 7 or 8 psi of boost. Nothing wrong with exhaust liners in the head. Re-torquing the head gasket would be a good idea and changing the stock fuel pump to a MSD-2225 (90.00) will also be a good thing. Good luck with your project.

Here is an easy way to do it.

If you assume that 1:0cr gives about 5% increase in hp then a 10.3:1 would have 10% more power than 8.3:1 cr. And if a stock 75 to 80 L28 (8.3:1cr) makes about 135hp at the wheels then you should be able to get about 149hp. Then a header will add a few more hp 153hp. Close to 160hp. Of course assuming you don't have detonation issues. You need a cam badly to reduce detonation and make that header work for you. Maybe make another 15 to 20hp with a cam (170 to 175hp!) It should be less than 60.00 to get your old cam reground. You need a cam with at about 220 to 230 degress of duration at 0.050". Courtesy Nissan sells lashpads for 3.00/each.

You need a lot more compression. I run 11:1 cr with a slightly small cam than yours. And I use 93 octane with 38 degrees of timing with no detonation. You need a 3000+ converter for that cam. And your 3.70 diff needs to be a 3.90 or 4.11. If the cam is 256/268 advertised duration then you gear, stock converter, and compression are just right. But your heads are too big if the cam specs are advertised duration. A 215cc intake port is a pure drag racing head for a 350. I use the dart 200cc on my street/strip Z. I tired the 700R and hated it!!! Nothing but problems with it. Ended up with a GM T5 and it works great. My 240 runs 11.7's at 120mph all motor, and 10.7's at 135 with 150HP of N20. But at this power level it eats up diffs and axles. Once a Z gets into the 11's it is time to upgrade to a solid rear axle and a 4 link.

290 hp is the rating with a set of full length headers which is a hard thing to get into a V8 Z in the set back position (JTR conversion). With block huggers it will be lower, like 275 or 280. Still, not a bad engine for a 3.54 gear and automatic trans. Should be able to run some 14 flat at 100mph, 1/4 miles. A mild cam swap (268 duration) and some mild bowl work on the heads could get you easily into the 320 hp range. Maybe mid 13's at 105mph Then later swap to a set or vortec heads (64cc) and gain compression and air flow. Should net at least 350 hp. Maybe high 12's at 110. Go to chevyhiperformance.com and look up their old tech articles. They did a 8 part, 350 goodwrench engine build up. They ended up with over 500 hp. For exhaust, I would recommend Hooker Header Super Comp Block Huggers with 2.5" pipes, Y'd into a single 3 inch pipe right before the diff, then a single 3" dynomax muffler. And use a Holley or Q jet carb with a mallory comp110 fuel pump. Avoid the carter/edelbrocks carbs and holley pumps. good luck

I don't like the LT1 ignition systems. So i would go for the 5.3

I have seen new flat tappet cams go flat on the break in. Not an issue if you are using a roller cam. New cams can go bad very quickly if then is some kind of oiling or clearance problem. If the Holley is doing the same thing as the old carb then it is most likely not a carb issue. Nice carb you got there, by the way. I would use 70 jets up front to start with. If the Vortec heads were not modified for more lift then that would be a major problem. You can check the clearance with the head on the engine by removing a few valve springs. I use the compressed air in a cylinder method to remove valve springs. This will allow you to remove the valve springs in order to check retainer to seal clearance and spring installed height. Check the clearance by lowering the valve and reatainer (no spring and no air pressure) all the way to the seal and subtact the lowest point from the highest point (valve all the way up). Then with the spring off, you can check coil bind height using a bench vise and a micrometer. I fill my cylinders with compressed air by removing the "one way valve" in a standard compression tester hose and connect the gage end of the hose to my air compresor. FYI, the compressed air holds the valve up on the seat when the spring is removed.

15 psi of boost on a 350 goodwrench engine will make 500hp. Your 500 hp, turbo V8 goal should be pretty easy to get. good luck

I worked on a freinds 280Z turbo recently that was doing kind of the same thing. At the point when the wastegate opened, the engine would start to buck and fall on it's face. I couldn't figure it out until the head gasket blew and filled a few cylinders with coolent. We had the head resurfaced and changed the head gasket and that fixed the problem with the bucking. I'm guessing coolent was leaking into the cylinder during boost. However, I'm not sure why it would only do it when the wastegate opened. I mean it only did it at the point were we set the wastegate to open. weird.

I'll give it a try and show my work. 383 is about 47.875 cid/cylinder or 784.5cc's/cylinder cylinder volume= 784.5cc gasket volume = 8.6cc piston in the hole=4cc cylinder head=70cc piston dish=12cc total volume with piston at bdc= 879.1 cc total volume with piston at tdc = 94.6 cc Compression ratio is 879.1/94.6 = 9.29:1 cr. Assuming the piston is below the deck 0.020".

I love Q-jets! Great gas mileage and they sound wonderful and they run strong. I just don't like the looks of them. hahaha. Not a good reason to not use a carb but that is the truth. I use 750 holleys 3310 on just about everything. I tried two different eledbrock/carter carbs on two different cars but just ending up throwing them in the trash, the place they belong.

Get a Mallory Comp110. Quiet and last a long time. A little more expensive but worth it. I like the Mallory because I like to hear my engine over the pump and I like my pump to last me for at least 5 years.

If the fuel lines are too small it would only have an effect after a long full throttle run. It seems like you are having throttle response problems. A pop out the carb is a lean backfire and/or retarded ignition timing. Years ago, I ran the stock 240 gas lines on a V8 conversion and it ran mid 12's without any fuel starvation problems. And a 240 has smaller gas lines than a 280!