Pyro

I agree with what you are saying. I need to upgrade to an aftermarket efi to do it right. But that takes a lot of time, work, and money That is why it is easier to throw on another pump to get the pressure in need for the fmu. 100 psi isn't that much. A friend of mine uses 120 psi on his twin turbo Viper and the car is a daily driven monster. However, my turbo is in a 76Z with the stock ecu (non-turbo) so a FMU is required. Bigger injectors will make the car run super rich off boost, so I'm just trying to see how much I can get away with at the monent until I find the time to do it right. The car pulls strong to 6K and doesn't detonate or surge or kick. It pulls hard and smooth all the way to redline. The plugs look good and all systems seem to be doing great. So, I'm not to concerned with engine damage I do appreicate your concern but this is one of many car projects that I have going on and I could blow up the engine without any real hardship on my part. I have other cars to drive to work and this is kind of a toy right now. I thought it was just interesting how applying a little positive pressure to the atmostphere side of the wastegate could make huge gains in 1st and 2nd gear boost response. Could be usefull to install a weaker spring in your wastegate and use a regualtor to bring the boost back up and gain turbo responce at the same time.

Ever since I switch to a T4/T3 I wasn't getting full boost in 1st and 2nd. In 1st gear it would only boost to 5 or 6 psi before it hit red line then in 2nd it would start boosting at 3500 then slowly make 12 psi by 5500 rpms and not go any higher. However, in 3rd gear it would be at full boost by 3500. So I installed an ajustable pressure regulator so I can increase my boost with a twist of a dial. I have a Delta waste gate so boost pressure can be increased by applying a small positive pressure to the "atmostphere pressure side" of the wastegate. I tee'd in to the pressure line going to the wastegate to devert some pressurized air into the regulator. Then ran the regulated air into the other side of the wastgate. I dialed in the wastegate to 10 psi and set the pressure regualtor to 5 psi. Now it boosts to 15 psi in 3rd gear just like I expected. But the big difference is now 1st and 2nd go on full boost by 3500 also!!! Man, what a rush! Second gear now breaks the tires loose at 4000 rpms. I guess the positive pressure from the regulator is helping keep the wastegate closed in first and second gear. The wastegate must have been opening due to the large amount of air trying to exit the exhaust manifold in the lower gears. Now the t4/t3 seems as responsive as the stock T3 turbo! I was missing my T3 turbo but not anymore. I also going for the record of most HP with stock NA injectors and stock NA ECU. I running 100 psi of fuel pressure at 15 psi of boost and running 27 degrees of ignition timing without any problems. However, my fuel pump system consists of 3 pumps in series: a low pressure pump (Mallory 110) that feeds two high pressure pumps (MSD). This was the only way to deliver 100 psi with high volumes. Not the best way to do it but it will get me by until I install megasquirt. Finally, I can't believe no one knows the detailed cam specs for the MSA stage 1 turbo cam!

I bought my turbo from Majestic turbo in Dallas Texas for about 600.00.

T5 will not handle a turbo charged V8. I run one in my V8 Z and have broke it several times. FYI, slow shifts will extend the life of a T5 but it will also slow down et's. Another thing, you would also need to run a very heavy clutch to hold that much torque which is a pain. I had to build a firewall support because the firewall would flex when I pushed in the clutch which reduced the pressure plate travel. Over the winter months, I'm planning on converting my V8 Z to a straight axle and automatic car. I feel I have hit the point were I have too much power for the stock rear end and GMT5. I break parts, eat clutches, and don't ran as consistant as I would like. I have a 400+ hp 362 cid then a 175 shot of n20 on top of that. The car runs 11.7's at 120 on the motor and 10.7's at 135 on n20. I think mid 11's are about as much as a T5 and a R200 can handle. Sure, I ran 10's with my setup but not for very long. If you want a safe and durable track car that runs better than mid 11's then go with a 3 speed auto and straight diff. I had very bad results with 700r's. I don't want to even think about how much time and money I wasted trying to get a 700r to handle decent power. Use a 350 trans prepped for drag racing (manual valve body and trans brake)

I have the black magic fan on a 350 chevy in a 240 and it works very well.

I'm using the t04b compressor with a H3 wheel along with a T3 stage 3 turbine. It works great! However, it takes longer to spool up than the stock T3. Full boost by 3500 for the T04b and full boost for the T3 by 2800 rpms. But I did notice more off-boost power with the t4/t3. And of course, more rpms with the t4/t3. Furthermore, the t4/t3 gets better mpg and is smoother on the highway. But I do miss the high torque feel of the t3 at lower rpms (2k to 3K). So, there is always a "give and take" when it come to performance.

I'm interested in buying the MSA stage I turbo cam. I call MSA but the tech guy didn't know the "detailed" cam specs. He took my phone number last week and said he would call me back but I have the feeling that it isn't going to happen. So, does anyone know the opening and closing points for the MSA stage I turbo cam? I did a search and didn't come up with the information. And if you used the cam, it would like to hear how it worked for you! Thanks.

Delta Cams resurfaces rocker arms for 3.75 each (45.00 for 12) and grinds cams for 65.00.

Ignition timing also adds to the equation. Rich mixture combined with retarded timing really makes cast iron glow. Not sure if lean mixture will increase exhaust temps. However, a lean mixture will cause dentonation which will crack pistons. I haven't researched on this subject, but it seems to me exhaust temps would be lower with a lean mixture. How do you make heat without fuel? Maybe a high oxygen content burn is hotter? Exhaust temps will rise as the turbo is working. Boosting for long durations will increase exhaust no matter how good the fuel ratio is.

Go to any metal recycle shop. They will weigh your car for a couple of bucks.

After market heads kick butt. Those old stocker just don't do it anymore. The head will work ok but you will lose 30 or 40 hp! And by the time you install springs, bigger valves, screw in rockers, port work, and a valve job you will have an old set of heads that cost more than a better performing new head. If you want to build a mild 350 then use flat top pistons, 76 cc combustion chambers, 180 to 195cc intake ports, and a 210 to 220 degree cam. 76cc combustion chamber will make 9 to 9.25:1 with a 350 flat top engine. If you want to build a hot 350 then use flat top pistons, 64 cc combustion chambers, 195 to 215cc intake ports, and a 230 to 240 degree cam. 64cc combustion chamber will make 10 to 10.25:1 with a 350 flat top engine. Consider the following heads from summit racing or jegs: dart iron eagle, world products sportsman II, trickflows, AFR, or GM vortec heads.

Nice run! But the time and MPH do seem fast for only 180 hp at the wheels. My bummerless 76 with stock L28t, spearco IC, ran 13.7 at 106 mph with 12 psi of boost made 235hp on the dyno. I would expect 100 mph with 180 hp at the wheels in a 280Z. So maybe your dyno is wrong! The "1/4 mile dyno" is always right on.

IMHO I think it is a big mistake to put duals on a 6 cylinder. The sound pluses from two three cylinder banks have sloppy and cloppy sound. Maybe if you also install a balance tube it might sound fair. In a single exhaust system, some of the sound pulses cancel each other out thus producing a smoother, cleaner, consistant note. Plus datsuns don't handle two pipes going down the center and around the diff and tank very well. It takes 8 cylinders or more to make a good sounding exhaust with duals. (Except in a V10 dodge viper which always sounds like something is wrong)

very nice! I'll pass it on..

I know someone here in San Antonio that might be interested. What are the trucks specs and how much are you asking?

Mike C What is it with Z's and old chevy trucks! I have noticed a lot of Z owners also have the 67 to 72 chevy trucks like you. The Z and the 67 to 72 chevy truck have something in common, somehow.....? I also have a 70 chevy C10 LWB, built 410 BBC, TH400, AC, PS, PB, front disk brakes, 5 lug conversion, 3.08 limited slip diff, 4" front and 6" back lowered body.

No info on your compression ratio, diff gear, or transmission used. But this is some general guide lines I like the CompCam 260. Works great on stock engines (low cr, weak valve springs, and stock converters). Plus improves highway MPG. A comp 268 is a little bigger but would required new valve springs and a 2200 stall converter if an automatic is used. And will run best with 9:1 cr.

Sorry. I gave you the wrong information. The FMU is made by Vortec, part number VOR6X100-001. Summit sells them for 280.95.

I'm not sure where he got it, but it is huge! About 4 inches diameter and 2 inches tall. It has three adjusting screws on it; one for idle pressure, one for low vacuum, and one for boost. He had to run 20 psi at idle because he is using a non-turbo ecu with turbo injectors. Do a search on the web and you should be able to find it. If not, i can get the part number from him.

Did the dyno guy measure your Air/Fuel ratio? 165 hp sounds right for 5 psi of boost. (5 + 14.7)/14.7 = 1.340 1.340 x 125 hp (stock L28 hp)= 167 hp. If you're running NA injectors you need more fuel pressure! Next time try 10 psi of boost and 60 psi fuel pressure on the fmu and you will make 210 at the wheels.

I recently installed those MSD pumps and I have seen those graphs. However, I don't think they flow as much as advertised. That is why I added another low pressure fuel pump. Go to RC engineering. There are a lot of formulas to calculate flow for injectors. For example: ((new pressure/old pressure)**1/2) x old flow rate = new flow rate so a 190 cc injector at 75 psi with flow the same as a 260 cc injector at 40 psi. (75/40)**1/2= 1.369, (**1/2 is square root) then 1.369 x 190 = 260 cc. But remember the manifold pressure! Injectors flow less in a manifold with positive pressure. 40 psi is really 30 psi under 10 pounds of boost so 75 turns into is 65 psi. Therefore, a 190 cc in a 10 psi boosted manifold with 75 psi of fuel pressure (65) flows like a 280cc injector with 40 psi (30). ((65/30)**1/2) x 190 = 280cc.

My 78 dies when I pull off the oil cap. I guess that big hose going from the valve cover to the intake creates a huge vacuum leak and shuts down the engine. I guess this would also depend on the idle A/F ratio. My car must be running lean at idle. I'm sure that is normal. Especially after viewing the "Datsun Efi Therapy Video". The video saids, if the car dies or almost dies then that means no other vacuum leaks are in the system. The Video also said that the rear main seal can cause a vacuum leak! Datsuns are crasy! Try doing a compression test, check for broken valve springs or worn cam lobes.

I'm running 12 psi of boost with the Cartech FMU and I'm using stock 76 NA injectors and ECU. At 12 psi, I was runing 14.7 a/f ratio (dyno tested) with 70 psi of fuel pressure (too lean but 235hp at the wheels). I have recently increased the pressure to 85 psi and I'm finally making some black smoke out the exhaust. However, the biggest problem in make fuel pressure is finding a pumping system that can delivery high flow and high pressure at the same time. In all pumps, as the pressure goes up, flow goes down. In most cases, flow drops to almost nothing at 90 psi. An in-car flow pressure gauge will tell what is going on (get one). In my case, the stock pump could only make 55 psi under high flow conditions. Eventhough it would make 90 psi at idle when the return line was pinched closed. So setting the FMU higher did nothing! I needed more flow. If you install two pumps in-series (one pump feeds the other) then much higher pressures are obtainable. In fact, I use three pumps now! A low pressure pump to pull out of the tank then to a stock style high pressure pump (in the stock location) then to another high pressure pump which is mounted up front by the fuel filter. I can now (if needed) generate over 100 psi under high flow conditions!! However, two stock style, high pressure pumps should be enough to maintain 70 psi. MSD makes a big pancake type regulator that allows a lot of adjustment: (idle pressure, no vacuum pressure, and boost pressure ratio). I friend of mine uses one on his 78 turbo retro fit (stock NA ecu). He is using turbo injectors with an idle pressure of 15 psi, 20 psi no vacuum, and 50 psi at 12 psi of boost. This way he doesn't need all those stupid fuel pumps! The bigger injectors (24lb vs 17lb) help handle the flow requirements, not just more pressure. And the stock regulator is not used with this setup. But with all this said, an FMU is only a bandaid on a broken leg. We all need to get new programmable EFI's to do it right!!!

I have used square port manifolds and headers on round port heads without any problems. Hold the gasket up to the head and you will see that it will work.

I should be a consistant flow. How much fuel is in your tank when you did the flow experiment? My tank has pick-up problems below 1/2 tank. I'm planning to pull my tank and weld in a 1/2 gallon sump below the tank.