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77 turbo upgrade


nategdizzle

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Hey guys I was just wondering what everyone thought about putting a turbo on without putting flat-tops or doing anything to the internals of a great running 77 L28..am i heading for immediate trouble or will i be able to run 4-7lbs of boost without trouble until i can get some time and money to tear the motor down and start fresh..i have the stock n47 head with the steel inserts and i plan on removing those but other than that i have zxt injectors, 60mm tb, rajay turbo setup, 83 zxt dizzy, 300zx dual pick up wheel, microtech lt8 standalone ecu with a msd 6btm ignition controller, i am on the lookout for an intercooler as well and i dont know what im going to run for exhaust yet so if anyone has any ideas on what the best setup would be im open to suggestions.

 

Thanks A Lot Guys

Nathan

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I wouldn't bother with a cam at those kinds of boost levels for the amount of money and work it takes to set up a cam properly. Just find someone with an extra stock cam - you shoud be able to find one cheap.

 

The Rayjay setup (if it is the old BAE kit from tyhe 70's) was designed to work on that engine so you won't have any problems - the standalone ECU will be a major improvement over the stock kit. I use a Rayjay on my 260Z and am very impressed with it's durability. It does spool slowly due to the large exhaust housing and lack of wastgate. I think the stock kit ran about 6 psi of boost but you can get stiffer springs for the BOV from any hardware store.

 

When it comes time for a cam (15 psi +) there is a cam grinder here in BC that is very good (Colt Cams). I have used several of his cams with good success.

 

I wouldn't spend tons of money on that head or block if you are going for a budget setup. Try to find a stock 280ZX turbo engine in running condition and swap it in complete less the computer. Better pistons and better head.

 

Good luck!

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  • 3 weeks later...

Well I'm back to work on the z after about a month of letting it sit and all i really need is a z31 300zx pick up wheel for my microtech lt8 ecu and i have a stupid question I wasnt sure if the pick up wheel was what i would call a crank angle sensor or if it was just a part of the crank angle sensor or i am barking up the wrong tree:) if someone could clarify that it would be awesome...also i was wondering what some of you thought i might be running for hp and torque with this setup

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i have the stock n47 head with the steel inserts and i plan on removing those

I read somewere that those steel inserts was to "burn" off unburnt fuel in the exhaust.

 

What bad do they do, and whats the point of removing them?

 

I really want to know, cause I have a -77 car with "stock" engine,

and going for turbo in a while... I got zxt manifoilds and bigger injectors from a supra turbo laying around waiting.

 

It`s now running kn-airfilter and some better exhaust, and Autronic SMC engine management running waste spark, my g-tech showed 159rwhp.

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another question for you guys, i have been checking around the machine shops here in iowa and none of them know jack about 280s and havent done any and want to charge me up to 750bucks to get a valve job with larger valves and and have both the intake and exhaust ports ported and polish the exhaust ports, anyways i was wondering if anyone knew any shops that they have had good luck with and is cheaper maybe..i would be willing to ship about anywhere, also im still looking for a z31 300zx crank angle sensor and could use some help in locating one

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sorry about my constant posts but i am trying to finish this project up as fast as i can and this seems to be about the best way to find stuff out...i just got a n42 head and a t3 turbo to replace the rayjay one i was going to use cuz the rayjay one isnt really worth the effort for the performance i want. oh yeah the guy had a z31 cas plate he threw in for free so that was cool. so i know have pretty much everything but what i was wanting to know is is an 83 zxt t3 turbo oil or water cooled? does it have a waste gate, if not what should i use for one?...and what exactly is a t3/t4 hybrid

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You should definately get a blow of valve!! It protects against compressor surge. If you don't have a blow of valve, when you suddenly close the throttle(If you are changing gear or braking), all the air that is rushing towards the TB will meet a closed throttle, and thus crash into it and move in the opposite direction back towards the compressorwheel. When this happens, the compressorwheel will be forced to a sudden stop. This can cause damage to the compressorwheel and the bearings. Furthermore since the wheel stops spinning, it will take longer time go get it spinning again when you are have changed gear and are accelerating.

 

If you have a blow of valve, when the throttle is suddenly closed, the vacuum in the intake manifold will act to open the blow of valve, so that the air that has crashed into the throttle and changed direction can flow out of the blow of valve instead of back towards the compressor. This enables the compressor wheel to keep spinning, so that when you once again accelerate you will experience less lag.

 

So the blow of valve does two things, it protects the turbo from compressor surge, and it helps reduce the lag you experience when shifting gears.

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yeah thats what i figured, thanks..i have a few more questions for you guys. Is there such a thing as a cheap wideband o2 mixture setup. i would like to go wideband so i can do a better job on tuning but i dont feel like spending more than $150 or so..should i just go with a narrow band o2 setup? how big of valves can you go with in an n42 head before you have to get new valve seats? i want to push my boost to as much as my zxt injectors will take, but i dont really know what they can take. i think i have heard that around 11psi is when you will start to run out of fuel with them. i was wondering what people thought about that. i kinda figured that i could always put a couple of supplemental injectors in my intake pipe after the intercooler later when i want to get more boost.

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is an 83 zxt t3 turbo oil or water cooled? does it have a waste gate, if not what should i use for one?...and what exactly is a t3/t4 hybrid

The 83 zx t3 is internally gated and oil cooled only. A t3/t4 hybrid is a t3 turbine section combined with a t4 compressor section.

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i just read an awesome post from braap about heads and flow and it got me to thinking about my compression ratios some more..i really havent put a lot of thought into it but what is the "ideal" comp ratio for a turbo l28..i started pulling my head off but and decided to wait till i got my new one cuz i dont have a good clean place to work really and i didnt want it sitting open in my dads dirty machine shed full of tractors. but since i havent pulled it off i havent been able to see if i have dished pistons or not, did 77's have dished pistons. mostly what i want to know is what my comp ratio will be.

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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.

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