zeiss150

Hey Doug. If your plan is to have RWHP of 250 or so you need to dump the entire 280zx ECU. Even with all kinds of mods It still isn't up to the task or real HP. The Z31 is an "ok" substitute but it still is lacking for the kind of WHP you want. If you use Megasquirt or some other type of aftermarket ECU you will be able to trash the entire stock ECU and wireing, and yes megasquirt can run the distributor (it controlls the timing). I think the size of the Injectors are 11mm or something like that. They were 260cc (or was it 280cc?) for the turbo but most guys upgrade to the toyota supra turbo 440cc injectors. More important than building a forged bottom end is getting a quality FI ECU that can make you the power you want. There is a step by step thread on swaping in a Z31 ecu into a zx harness but why bother. Stock compression on the 280zx turbo is 7.4:1 and off bost it is suposedly a dog... keep in mind this is hearsay I've never driven a stock turbo zx. If you want the car as an everyday driver 300 WHP can be made without pushing the L28 to its limits. I think the limits of the L28 (for most mortals) is 500 WHP or so. But having that much WHP does not make for a daily driver. 1/4 mile times... well that depends on the suspention the wheels the tires the engine, and oh yeah... THE DRIVER. There was a guy that ran high 12's with a non turbo SU (carborated) 240. I think Austin is trying to break the 10 second mark and he's got 460 but i think he has plenty of HP to reach his goal. Oh I forgot to give my general disclamer: I am a retard, and all the info I have given you is subject to correction by much smarter Z'Ophiles than myself. All stated info should be taken as a "possible" fact and further investigation should be done to verify said "facts". Keep the Q's comming and I'll do my best. Matt-

I think a forged bottom end is a lot more than a few hundred dollars. I wouldn't use the forged pistons from AZ Car with out the 240 rods... whats the point you would just be lowering the CR and thats the opisit of your goal. I was not trying to talk you out of a stout bottom end, if you have the cash... go for it, but if you're on a budget thats a good place to save money. Dizzy is just slang for distributor (just like you thought) There are basically 3 kinds of Z dizzies: point (240z), reluctor (280z- N/Azx) and the Optical Crank Angle sensor (280ZX turbo) You should use the one that is on your turbo donner car It works with all the computer systems that you might run. The Other Dizzies work best with N/A engines. The T5 Borg warner Tranny will work fine and will fit fine in your 77 280Z. I think the only mods nessary would be the trans tunnel mount and the shifter whole needs to be trimed so that the BW shifter doesn't hit. I belive that the N/A ZX 5 speed is considered the better tranny for a turbo build. If you wanna go crazy you can put a Z32 6 speed tranny in there (it will cost some $ and mods) there is also a 240SX 5 speed tranny swap that is good for up to 350 WHP. Suposedly the BW tranny blows second gear (or one of the other gears) pretty easy, Im just going off memory from previous post, so Im sure that others with more tranny info will chime in. Keep the Questions comming Matt- P.S. tranny is slang for transmition:wink:

I forgot about using the 240 rods with the forged pistons. I think they have 8mm ARP rod bolts now, so any year 240 rods should work great with thoes bolts. The reason that you didn't need to change your ECU is because it was late 1990's tech. The ZX turbo ECU is from 1980... think about computer tech in 1980. does the comador 64 ring any bells. So the stock ECU is just not up to the task of a performance turbo engine. The Z31 ECU is only slightly better. I am also intimidated by megasqurit but there is tons of info and people to help. Keep in mind your WHP goals, If you are looking for 300 or less I wouldn't worry about forged bottom end spend your money on a better turbo better ECU better BOV,RRFPR,exaust, down pipe,radiator, IC, Clutch, and suspention. Now if you want Austin kind of WHP ... forged bottom end is a great idea. Matt-

The N42 isn't a good choice for turbo ... I whish it was, because I have an N42 on my L28 right now. The CR would be right but the design of the chambers don't have the best characteristic to prevent detonation. The P90 head (which is the stock turbo head) is the best head for turbo application. Right now there is a hybridZ member that is making 460 RWHP on the Stock P90 head and cam. Forged pistons is a great idea if you intend to make that kind of power. If you are looking to stay in the 300 WHP range stock pistons should work just fine. If you want that sweet spot CR of 8.5:1 CR then just use the P90 head and the N/A FLAT TOP pistons, that combo will put you right at 8.5:1. If I remember correctly Arazona Z cars sells flat top forged pistons that will give you 8.5:1 and they will also change your pin height so that you have a better stroke raito. The hardest part of building a turbo motor is deciding what you want to do with it. Because the L28 is so versitile you can make whatever L28 turbo your wallet can handle. Good luck and let us know if you have any other questions

I've read a bunch of times that after break in you should re-torque the head bolts because after the first heat up and cool down it could loosen the bolts. Just a place to look.... If they all still torque to the right specs then you know thats not it.

white smoke is usually water (steam) did you re-torque your head after first runin? the bolts could have loosen'd up. I know you said you checked the water but Im just throwing out stuff. good luck!

I do remember reading a post on a Z site about the N47 head flowing better than the n42 ... I remember the guy even had flow charts to back up his clame. Im gonna be using a P79 for a turbo project, everyone always freeks out over the steel liners but If it flows better... right now I have an N42 head with a mild cam... not very good for a turbo project What are you going to run for your fuel delivery... SU's, Triples, FI? Matt-

Hey Phill great job on the video's! Please make a step by step video of your mega squirt install, including the 440cc injectors. I plan on doing the same install and I would love to be able to watch someone else do it first. Thanks again. BTW how did that Paint job buff out?

Hey silent, why did you go with the N-47 head just wondering Matt-

hey guys, are the mkIII supra turbo 440cc injectors 14mm o-ring? If not what are they and what kind of mods to the intake are nessary to make them work. As always thanks for the info.

how much WHP do you want? If you want over 200 then you should think about turbo charging. If you don't want to deal with the turbo stuff then loose those webbers and ether go with an after market FI system or 72 or earlyer SU's. The P79 head is a great head and I don't think you need to replace it in either case. Head work alone wont get you a ton of power. More Wheel Horse Power comes from a comprehensive system of engine components. You can use any Z 5 speed ... but , the stay away from the turbo 5 speed I've read threads about 2nd gear blowing really easy. also keep your 4 speed shifter so you don't have to modify your 260 body. good luck

A stuck valve could be anything from a bent valve to a poped valve seat. or it could be just as simple as a miss adjusted rocker arm. the price for repair depends on if they have to pull the head. If they have to pull the head then you are gonna pay, If it can be fixed with a rocker arm adjustment then it should be cheap. If its a bent valve then you may have WAY BIGGER problems. If thats the case then you may have to have the entire engine rebuilt. I'm just giving you the worst case senerio, so you're not shocked if the mech tells you it'll be $3k to fix it (make sure thats for a total rebuild though... and even thats to much IMHO) If you are at all interested in Z engines I would refer to you a book named "how to build your nissan OHC engine" at the very least you'll know if the mech is ripping you off and at best you can fix the engine yourself. Good luck and keep us updated

good point about the gasket... I'm just trying to find that perfect ballance of a snappy off boost engine that will scare the $hit out of people with 12 psi Im guessing that is a magic # of between 8-8.5 CR. Right now I'm driving a 9.2:1 N/A Z and it is quick.

15lbs from a t3 is a lot of boost but not compaired to a t4's 15 or 20lbs. I plan on running megasquirt with 440cc injectors and a super efficiant IC I'll start with 7 psi on my my nissan Z31 t3 turbo and see how that go's then i'll slooooooooowly bring up the boost. I have an HKS steel head gasket but If I use it my CR will drop to 8.1:1 so instead of using the steel head gasket I think I will go with studs. I supose that if I go with the 8.1:1 CR I can alway upgrade to the t3/t4 hybrid turbo and get over 350 to the wheels. am I being niev? am I missing something? My goal is 300 to the wheels so once I reach that ill stop raising the boost. Thanks, Matt-

Im going with 8.6:1 CR when I build my turbo engine. that should give me a "snappy" off turbo engine. I don't plan on running huge boost thought, about 12-15 psi. I think 7.4 CR is better for a bigger turbos and higher boost... but im still learning. If I could get one of thoes Giken twin cam heads ... now that could be fun to turbo

why are you going with a 2.6? there's no replacment for displacement .... L28 can be found at the junk yard for about 75-100 bucks 2.5 inch exaust is great for a N/A Z With that maxima head you will need to watch your CR... you might want to go with FI and some really good engine management to controll detenation. I would guess with the set up you listed you could get a 15 sec car easy If you went with the L28 and other stuff I listed you might get into the low14's or maybe high 13's..... maybe. I think theres a 12 second SU guy somewhere out there. Good luck and let us know what you do! P.S. where are you in Cali?

well you seem to know your engine choices, but ... you left out one pretty obvious engine... L28. If I were you I wouldn't build an engine for my Z based on max RPM. I would go for a Rear Wheel Horse Power 200, 300, 400, 500, 600, and do you want it N/A or turbo. Do you want a race car or do you want a really fast every day driver. A turbo L28 can bring you great torque and RWHP without too much trouble. And don't forget about SBC V8's and nissan VG and VQ engines. I guess the ultimate choice will be made by how much money you have to drop into the engine you pick. Good luck

If he built it for a turbo application he might have just used the n42 block... they are suposedly better than the F54. It could have an N42 block with "turbo pistons" and would make the bottom end the same as a stock turbo as far as the internals go. The P90 head is definatly for a turbo. If you wanna replace the pistons then replace them with flat top pistons that will give you 8.5:1 CR pretty good for a N/A engine. If you use a 1mm head gasket you'll get a little higher CR 8.7:1 these CR #'s are only good if there was no bore when the engine was rebuilt. That top ring of carbon is normal engine ware. Its there because the top compression ring doesn't go to the top of the block. the piston reaches the top of the block and there is a space between the cylinder wall and the piston so carbon builds up there. you have to be careful when you take the pistons out if you go through the top because that carbon ring can get really hard and it can damage the piston on the way out. but Im sure that yours can be taken off with a scotch brite scratch pad. Just my opinion but I would go turbo if I was you... the N/A set up might get you 180 HP to the wheels ... but a well set up turbo will give you 300... just a thought. Good luck .... Matt-

why are giving up a on the N/A ... just wondering... and dont feel bad I am too. But I love my Z and I wouldn't give it up no matter what. I'm going turbo gause I want 300 WHP and you just cant get that with out a turbo. I think the set up you have there will be able to get you 300 WHP pretty easy. If you went with the t3/t4 hybrid turbo you would get that and a lot more. Good luck... Just watch your CR ... depending on what kind of pistons you are using will change that dramatically.

I might guess that the smoke out of the turbo is from running it really hard and then shutting off the car without letting the car/turbo cool down. If you didn't let the turbo cool down then you might have coked the oil and messed up the turbo seals. if thats the case then oil will leak out of the center section and run down through the turbine and into your exaust... I don't think it would hurt your engine, as long as you didn't run the car once it over heated .... but I'm wrong all the time:redface:. Good luck, keep us posted.

wow ... I've never heard of an N42 with round exaust ports... I know the N47 had round exaust ports with steel liners in them the N42 does have round intake ports ... maybe its some kind of weird Auzzy head? 8.5 to one is a great CR if you dont want to use supper high boost levels. The N/A engine that I built has flat top pistons wich makes the CR with the n42 close to 10:1 with the 2mm HKS gasket (wich I have on my engine now) it lowers it to 9.2:1... just a little to high for a turbo motor with that head design. If I use a P79 or P90 with my flat top setup then I get a nice 8.5:1 with stock Head gasket... so that's why I chose the P79 head. Like I said the N42 head can be used and has been used ... but is it the best head for turbo... probably not. Matt-

The N47 head on the 280zx was never used in a turbo application. I thought about using the N42 head for a turbo application (because I allready have one on my N/A engine) but I decided against it because that head is prone to detonation at higher compression raitios. The P79 would work for a turbo really well and of course the P90 works great. I know there are some guys that have used the N42 in a turbo motor and but they kept there motor will a lower CR. If you decide to go with the N42 head take lots of pictures and write it all down then share the info with the rest of us. Matt

the quick fix is to throw a little grease on the outside of the throttle shafts. A nice thick bearing grease will plug up the throttle shaft leak. Its a temporary fix but it works. I called my local carborator shop and asked them if they could replace the bearings in my SU's and they said, sure. give it a shot... whats the worst that could happen:) Matt

I want that tc24 b1 head! what do you guy's figure 300 whp N/A with that head? It seems like there would be a pretty good market for that head if it were priced in the $1000 range. didn't mean to hijack the thread ... carry on...

why are you going with such a low CR? It might be kind of a dog off boost. If you are only gonna run 12 psi you can afford to use flat top pistons and get that CR up to 8.1:1. Just wondering. Good luck!