Lockjaw

HKS quoted 245 HP on a ZXT with all their supporting mods and an intercooler and 12 psi, so 225 seems reasonable. 980 made some good points you should think about. Fuel is the key to making power with a turbo. Having a good intercooler is also a must. I would spend my money where it counted and get a good spearco intercooler and sort out my fuel system before I got to deep in the project. I have the JWT upgrade with 420cc injectors, and am pleased with it. They may have to re-chip me for larger injectors soon, since I am upgrading the turbo, but that is not a big deal. The other thing about the t4 that was not mentioned is you have to use an external wastegate, so that is extra money you will end up spending. Good luck with it.

For main jets, take your " choke" diameter times 4 to get an apporximate main jet. Add 60 to the main for the proper air corrector. That is your starting point.

I think the diff between a datsun turbo and non turbo on the Zx in the location of the system as far as exit on the back of the car. ZXT on drivers side, ZX on passenger? I know ZXT is right not sure about ZX.

I could not find spacers thick enough so I ordered a 3 foot steel rod and will make some with it. Should not be that difficult, I only need three. Drilling the hole thru it will be fun though. I guess I need to go buy a vise now. Thanks for the tip.

I would make sure my timing was set right first. Then check your fuel supply and also the distributor cap and rotor. A cracked cap can cause problems as well. Also, make sure your harmonic balancer bolt it tight. Seems like I recall I had a misfire problem related to the balancer being loose. 1 3/4 SU's tend to denote the good kind, and I hope that is the case. Make sure they are adjusted properly, and that the pistons go up evenely when you rev the engine.

You can actually do alot with the factory turbo. The turbine housing is a t3, so you have half of the equation if you wanted to get a hybrid. Bang for the buck, a hybrid is a good way to go, and the Vtrim is a nice wheel for the street, and it can do about 400 crank HP or so with the proper supporting modifications. I would see about getting a good intercooler to go with a larger turbo, but once you get over about 12 psi, you really need to have larger injectors to add more fuel. Unfortunately this sort of thing is like a disease, and once you experience what kind of power turning up the boost add's, the tendency is to keep turning it up. You should also upgrade the turbine wheel to a stage II or stage III. I have the stage III and it spools nicely. You could also go with a larger compressor wheel than the V trim. I have the H3 which is the next size up, and it did not work well at all until I got over 12 psi. After that, it moves on.

He won't be doing that for long I bet. That is roughly a 32 lb per hour injector which could support about 388 hp at max duty cycle. Good thing he has a junk yard motor instead of a built one.

Vortec has a new one for carb engines, but don't know what the hood clearances are.

Tune for both places, and keep the spare jets for racing purposes with you so you can swap. When your car bogs, does it spit and pop out of the carbs, if so it is lean, if not rich. I would adjust the size of the pump jet, and maybe lower the main jet or increase the air corrector. You should not need a bunch of adjustment IMO, if your carbs are tuned right for 4k elevation.

Just imagine the looks on the Honda guys face when you wax his butt and he accuses you of having a V-8, and you pop the hood, and all he see's is MOTOR, and two little carbs. FI is the way to go, but SU's rock. I may change my mind after I get them up and going, but I kind of just like the nostalgia and all.

Any of you wizards think you can make one of these? http://www.zcarworkshop.com.au/Newsite/home.html

Scotty put some CV axles in that thing and be done with it. I have a mount that I am going to copy that will work at stabilizing the diff's in those cars. I have to go and get it from a friend and have it copied. It is pretty simple really. At least your car can go to the track, mine is in pieces, and the turbo is sitting on the floor waiting to be sent to someone.

I know who it is.

Looks like a Soundstream car amp to me. I am scared of new stnad alones until someone steps up and tries them.

I am sure that 89 mm pistons would bump your compression, your piston maker would be able to tell you very easily. I would think in the 8.5 range, but that is just a wild guess. Polishing the rods is something I did with a dremel tool and sanding rolls. Not the fastest way to get it done, but it works, and they looked nice. I got alot of compliments on mine. Just grind all the casting flash off the sides of the beams going lengthwise ie from big end to small end. DO NOT GO ACROSS. Bad stuff can happen there. Leave the old rod bolts in while polishing, and replace them with ARP bolts. YOu can get them from summit, and rod bolts are considered the weakest link in a Datsun bottom end. While I have never seen one fail, I think the 45 bucks or so for the ARP bolts is worth it. I have not polished the combustion chamber, but I would bet the swirl comes from the design of the combustion chamber itself, so polishing shouldn't hurt. Port matching the intake to the head would be good too. I did that. The dremel works good for that too. Let me know if you need any more info. Ordering pistons from a piston maker is going to be an experience in and of itself. Good luck.

I am in the process of fitting some SU's on a 260 I bought. I piddled around with them and had some problems initially, but then got them to behave. I ordered the video and some needles from Ztherapy and watched the video, and man did I learn a lot. If you think you have worn shafts, just get two replacement bodies from Ztherapy with the roller shafts for 175.00 for the pair, and get the video and transfer your stuff over. Balance the carbs like in the video, and go. It took me a good hour to get the two carbs balanced in the "drop test". I may have to get replacement bodies, but once I get my header situation straightened out, I will let you know how the car runs. FI will spoil you. I wondered why I went to all the trouble to come up with SU's when I could have just fuel injected it. I think in the end, I will get more performance from the SU's, but it will come with a price tag, namely not the easy starting I have grown accustomed to. Putting fuel injection on your car should not be that difficult. The biggest problem is going to be with the return line to the tank on the 240. It is to small to handle and electric pump other than the stock one. Good luck.

No I don't think you need to go forged, but I was kind of thinking you may need pistons, and if you do, spend the extra 20 bucks a cylinder and get the forged. To me it is worth it, and when you do forged, they really don't care what the bore size is, it is the same price, which is cool. Ross has their own rings now, and they are plasma moly coated ductile iron, which is what I put in mine, and they have held up very well. They have really never lived below 15psi since I have had them, which is going on 4 years, although usgae is limited. The last 2 have been 19+psi and race fuel only. I like the JWT set-up. I helped them tune the Cobra MAF on my car, and they got me running pretty strong, in my opinion. Drivability is incredible compared to the 280ZXT stuff, especially off boost response. I hit full boost by 2800 rpms, no matter what boost it is. The SDS seems to be a pretty good system too. They have some stuff they did not have, or I did not know they had when I got the JWT stuff, or I likely would have gone the SDS route. In the end, I spent alot of time on the phone with Clark at JWT, and I know he is selling something, but he covered alot of the pro's and con's for me. In the end, since I drove the car all the time, I elected to go with JWT. If I knew someone who had the SDS set-up, and I could play around with it, I could probably say more about it. Alot of people on the board use it, but I got into the JWT stuff right since my friend put me on the computer for his cost, which is way less than retail, the cobra MAF is about 200 bucks, and injectors, which you have to have either way, were about 80 bucks apiece. I bet they are the same as the mercede's one's people are using . It is strictly a plug and play deal which is nice. I think you would be pleased with it, and while I may change mine one day, I think I can pick up more power more economically thru other means. If I had lots of money, and nothing to spend it on, I would change to something like the Tec II or SDS or something.

Hey, Does anyone know where I can come up with some of those wide washers that are used to secure the bottom of the intake manifold and a header with a thinner flange than the intake? They are not the normal washers that nissan supplies, and they are about 3/4 inch thick with half of washer cut off about 1/2 inch to make up the difference in thicknesses between the header flange and intake. I have one leaking pig of a header, and want to seal it up. Thanks

Forged pistons will add about a grand to your bill by the time you get the pistons, pins, rings, and small ends of the rods bushed. I got Ross racing pistons, and they were 68 bucks each, pins were 110, rings we cheap since my buddy got me some sealed power ones, about 65, rods bushed were about 25 each I think, and you have to rebalance which is about 150. I polished the rods, had them shotpeened, and used ARP rod bolts. You also either have to drill an oil hole in the very top of the small end of the rod or two small holes in the small end at a 45 degree angle to the beam to oil the piston pin. If you have to buy pistons, I would bore the engine and pick up some displacement. You can go to 89 mm bore safely, which will give you approx 180 cubic inches. I went to 87 mm and should have gone out the other 2 mm. Good luck, there is no really cheap way to rebuild an L6 if you have to replace pistons. Nissan one's are almost as expensive as forged. You could look for a good used engine, and re-ring and bearing it and go. That would probably be the cheapest way to go.

None to my knowledge, and your chances of finding one in a junkyard are slim to none IMO.

I know a guy who did the boost NOS thing. He backed the timing and boost down a little, and ran at least 75 hp thru a single fogger. He said his car was faster that way that running bigger boost. NOS will spike your boost to high at its current set-up, so I would back it way down and then move it up in increments until you get the performance you are looking for.

I have the .63 on a stage III with an H3 compressor and have no boost control issue's with an internal gate. My turbo came with a .48, and it motivated off the line, but I always felt the top end was soft. Have not tried the .82 yet, and will likely got to a T4 instead.

The BOV must be plumbed back in the system on the MAF set=up. Mine fell flat on its face every time I shifted until I plumbed it back in front of the turbo.

I have Sealed power plasma moly coated ductile iron rings on my Ross pistons, and have lots of mileage on them with no problems. The factory chrome ones are good, but you really need to use a torque plate when boring and/or honing since the chrome will not seal well if your bore is not perfectly round. The total seal rings are supposed to be good stuff.

An easy way to get it off is to tape a heavy black plastic bag up on the inside of the window and spray windex with amonia on the tint, and put the car out in the sun.