Turbo Meister

Mike I used your listed specifications in my pro racing sim dyno calculator. The program allowed me to input your exact cylinder head flow as provided in addition to a calculated 10.3 compression ratio ( same as my 383 chevy ). The dyno indicated 451 hp at 5500 rpm and 470 ft lbs torque at 4000 rpm utilizing a hyd roller cam with 230/236 duration and .552 lift. This power level assumes optimized fuel and timing settings. I also have the pro sim drag program, which lists an early Z, into which any type of engine can be installed. In order for me to give you quarter mile results for your engine the program requires specific info on: vehicle weight, transmission, stall speed, axle ratio, tire diameter, launch rpm, shift points,track conditions and temperature. These programs feature colorful charts and graphs and are fun to experiment with. The drag program even measures g forces, drag in lbs at every level along the race course, and can input various tire slip equations. I have found that the quarter mile times for my engine combination in my Z is somewhat optimistic but doable with more suspension work and better tuning. The programs basically show you what your engine and vehicle should be capable of doing if everything is worked out. I doubt I will reach that point but I may come close. Hanns.

The only reason I'm posting this entry is to let everyone know that I'M the WINNER( so far ). In 3 weeks I will be "62". This poll clearly shows that Z and performance enthusiasts know no age limit. And every day I'm learning something new and interesting from hybridz members that are often 1/3 of my age. Hanns

I recently obtained the DynoSim Engine Simulator and DragSim Drag Strip Vehicle Simulator. The engine file actually contains a 2.4, 2.6, and 2.8 liter Datsun engine that can be modified. The drag file contains a Datsun 240zx ??? that will accept any engine and drivetrain from the engine dyno files. So long as you have specific engine component parts you can develop fairly accurate hp and torque curves on the program's dyno charts. My twin turbo 383 chevy shows as developing 815 ft lbs of torque. However, my 72 240z is more than 1/2 second slower in the quarter mile than the drag chart indicates it should be with that power output. Well, my rear suspension needs adjustment and maybe drag slicks would bring me closer to the projected e.t. Anyway, these programs are helpful because the itirators give you suggestions for performance improvement and the colorful charts are fun to print out. Hanns

This is a good 500 flywheel hp engine combination. With a slightly larger cam and 10:1 compression ratio my naturally aspirated 383 clocked a best of 11.15 at 123 mph through the mufflers. There never was any engine detonation on 91 octane supreme gasoline. You will not have detonation problems if you run around 34 degrees ignition timing. My Comp Cam had a 108 lobe separation angle and it was installed 4 degrees advanced. Good luck and I hope it will be tested on the dragstrip. Hanns

Tim, You have a great looking car!! I hope there will be some dragstrip forays after you button up the details. If it runs as well as it looks you will have one impressive Z. Please let me know if you are planning to run at Irwindale, LACR, or Fontana because I will be there if you go. Once again,congratulations. Hanns

Rick, That is one impressive frame and cage. It looks like it could handle any horsepower and torque you throw at it. I thought I took my Z down to the bare body, but you went far beyond anything I ever imagined. Your Z makes my backhalved one look like it is held together with rusty wire. Hope you race in Nevada next year so I can see your creation up close. GREAT JOB!! Hanns

It depends on how much power your engine generates and for what purposes you will use that power. My Z is "backhalved" with a Ford 9" because my TT383 Chevy develops a lot of torque. It never will handle like an IR rearend, but it's o.k. on the street if I soften up the adjustable rear shocks. Installing a solid axle rear end is quite a job on a Z because so much has to be changed. Unless you can do the modifications yourself it will be expensive. Consider your usage of your Z before you decide what plan to follow. Hanns

I read the info from the "Hangar 18 fabricators" and believe they definitely know how to prep a carb for blow through turbo use. Their Vega runs similar dragstrip numbers as my Z. They have not enclosed the carb inside a box, like mine, which requires much more modification. However, their system allows much quicker access for rejetting purposes. Their box intercooler should work well, but it requires a large hood scoop for clearance. My system provides plenty of clearance for the stock hood and maintains the street car appearance. But currently I don't have an intercooler. For a turbo blow through carb system you can't go wrong with their instructions. Hanns

Jersey,Yes, but sometimes it gets to be a pain when the tech staff nitpicks my Z because they know its potential. And then they pass a car thats held together by baling wire. I have even had them pull my Z out of the return road line and reinspect it at "street legal" events. My Irwindale dragstrip 1/8 mile times have lately been the "equivalent" of high 9 seconds at over 140 mph at 1/4 mile strips. But the tech staff realizes I have a well engineered and safe car and have, not yet, kicked me out. That's why Irwindale is fun. Hanns

Znow white, Thanks for the comments. Honestly, I am not familiar with the FI components on Z's, but basically any boost pressure applied to a fuel pressure regulator's diaphragm should cause that unit to respond and increase the pressure. However, your regulator or your fuel pump ( in my case ) requires a means to return unused fuel back to the tank. So, when I'm cruising on the street the pump sends 7 1/2 psi to the regulator and carb, bypassing most of the pressure back to the tank. At the dragstrip, at 15 psi boost, the regulator opens up and allows fuel at 22 1/2 psi to enter the carb. At that time little or no fuel is allowed to be bypassed back into the tank by the regulator. If your system functions in a similar manner then any plenum or other component registering boost should be able to send a boost signal. If my explanation doesn't help, the fuel forum, here, will surely have an answer. I agree with you, don't spend money on something if you can modify a part you already have. Hanns

The only problem I have with the turbos is that they are too large for the 383 engine. As a result there is more lag than what I would like, but they are on loan to me from a friend, so I can't complain. Also I dont need wastegates because max boost is only 15/17 psi. I recently discovered that my Greddy R Blow Off Valve had been leaking boost all along causing max boost to only reach 10 psi. My drag racing has been limited to running the 1/8 mile at Irwindale Raceway since discovering the additional boost, but my times during the summer have been in the 6.30's @ 113 mph through the mufflers. On the street the Z runs on 91 octane without problems since I generally control myself.The homemade carb enclosure works very well and minimizes the modifications necessary for the carb. On the other hand it takes me 20 minutes to remove, rejet and replace the carb in the box. I cut the carb's choke housing off, installed nitrophyl floats, and greatly increased the jetting. I don't have an intercooler but there is lots of CFM flow due to the short distance between the compressors and the carb. I modified my fuel pressure regulator by drilling and tapping a pressurized line into it from the box. This automatically increases the fuel pressure pound for pound with boost. Preconfigured fuel pressure regulators are available but I modified mine and saved $150. I'll run the Z next spring in the quarter mile with the increased boost pressure to see how much faster my times have become. I will probably get kicked out again for driving under 10 seconds without a competition license and chassis certification. Hanns

Glad to hear you are getting close to completion with you own 383 TT project. I have photos of my manifolds but I have no means to post them. However, I can send you copies if you provide your address or location to mail them. I will describe them and maybe that will be sufficient for you if you want to duplicate them. Picture 1" long 1 3/4" round header stubs extending from each port of the cylinder head flange. Then weld on a 2.5", 3/16" thick, square tube. Close off one end of the square tube and weld a turbo mount flange on the other end. You will have to add a short section of square tube before the turbo mount flange depending on how you want to orient the turbos. It looks rather plain and simple and not as sophisticated as stainless steel equal length turbo headers. But I'm totally amazed at how much power such a simple item can create. Initially, I built my prototype manifold out of PVC round plastic pipe and wood flanges to test the location and orientation within the engine compartment. However, the welder wanted too much money to weld a 2.5" round steel tube to the header stubs because all the tubing would have to be fishmouthed. I then brought him the square tubing and the welding began. The manifolds are compact enough to provide plenty of clearance so as not to damage my paint from the heat, yet not require altering any portion of the engine compartment sheetmetal. And I don't need a big scoop or raised cowl induction hood. My scientific research on what dimension square tubing to use was based on what my local surplus metal store had. My turbos are actually too large for this engine, so if yours are smaller you could use a smaller diameter tube for even more engine bay clearance. Take your time and plan well where you want the turbos to be located and you will be satisfied with the results. Good luck Hanns

I believe the Hot Rod magazine article cautioned against developing positive crankcase pressure which would act as a barrier to the oil draining from the turbos. This could develop since the larger ring endgaps, required for boosted engines, provide a wider path for pressure to enter the crankcase. I am routing this blowby, on my TT383SBC, through valve cover breathers into a catchcan via 3/4 inch heater hoses. I have not had any turbo oiling problems. I am looking forward to the coming turbo articles because there is so much more I want to learn about turbocharging. I have the Mcginnis book and Corky Bell book, but would like to get other up to date turbocharging technical material. Hanns

Thanks for the compliments. It took 18 months to build the Z in Naturally Aspirated form. I had it down to a bare shell so I could remove all insulation, rust and dirt. The engine compartment required plugging up 64 miscellaneous holes, alone. When I upgraded to the turbos it took another 3 month for the fabrication and installation. I have been cruising with, and racing the Z for a little over one year. Unfortunately, my white hair came naturally with age. But the first time I punched the turboed Z is a moment I will never forget. The thrust of the turbos planted me so hard into the seat that it felt like someone hit me in the chest with a sledgehammer. I couldn't even reach the shifter to go into second gear until I released the gas pedal. Turbos are fun! Hanns

Terry,Thanks for the comments. Although much of my turbo system is rather primitive and homemade compared to the sophisticated turbo systems available nowadays, I'm pleased with the way things turned out and hope other hybridZ members will be encouraged to build similar systems. By the way, the mere planning of system component placement took longer than the fabrication and installation. Good luck on your turbo project, Hanns

Jay,Thanks for the compliment. My Z doesn't have a hoodscoop and I wish I wouldn't have to have a rollcage so that it could be even more of a sleeper. But NHRA requires the safety equipment for my quarter mile times. While cruising on the street, a few times I noticed high performance cars behind me, that for some strange reason refused to pull alongside or pass my Z. Hanns

Ron,According to Corky Bell (Turbo expert), so long as the wastegate exhaust is plumbed at least 18 inches downstream of the turbine exhaust exit, there should be no negative effect in joining both exhaust streams. However, if your exhaust system is already too restrictive it would be better to vent into the atmosphere and not create additional restriction with the wastegate stream. Hanns

Hi,Thanks for the comment. Hope your Z will be paroled from paint jail, soon. Hanns

Jersey,Thanks for the compliments. I appreciate the info on the valve covers but I must save my money for new tires (For some strange reason the rubber keeps getting burned off ) and an aluminum radiator. I want both valve cover breathers at the rear so ,unfortunately, the flames on one cover point forward and backwards on the other one. Hanns

Rick,You have a great looking Z. I especially like the black stripes and the clean engine compartment. Will your Griffin radiator be able to handle the higher heat generated during the Nevada race? How well does it work now? My Z still uses the stock Z radiator and it tends to heat up more than I would like during full turbo blasts. I have been interested in attending the Silver State Classic and it would be well worth the trip just to see your Z in the race. Please keep me informed. Hanns

Sorry about the late response, I wasn't listening.When I first built my Z there were no plans to turbo the engine. I wanted as much power as possible from a street / strip engine. Therefore, I believed the 383 would be more powerfull at the intended use level. My best time, naturally aspirated, was 11.15 @ 123 mph. I was quite satisfied with the car's performance, until a friend offered to loan me his turbos from his 350 SBC race car. The rest is history. It would have been cheaper to turbo a 350, but stuff never happens in an orderly sequence. Hanns