Question for all you cylinder head guys!

[zxjuiced]

Ok here goes. I have a 1980 280ZX N/A EFI 5-speed mostly stock other than header and 2.5 exhaust. It`s basicly a virgin engine, never been broken apart. Engine only has 65,000 miles on it.Im the second owner I`ve had this car now for 15 years and now I wanna add some performance to the engine. I`m not going to be racing it in any fashion other than taken it out on some back country roads here in pennsylvania and horsen it from time to time. Ok now to get to the question. The engine is the N42 and the head is the N47.From what I can tell from reading thru this forum is that the N47 head is not a very popular head to use,so with that said what head do I want to get my hands on and what type of headwork should I have done to it, (machine work on the chambers, port/polished, bigger valves, springs, etc etc ???) and also what cam grind would you recommend?? keeping inmind I want it to also be streetable. This is the first performance mod I would like to perform first then maybe later down the road rebuild the bottom end.I hear to make a Z run, first put your money in the cylinder head! I wanna make sure my money is well spent in the right place with the right parts. thanks guys, looking forward to your recommedations.. zxjuiced

[PanzerAce]

...search search search search search

 

 

Now that that is out of the way, I don't think we can really give any advice until we know how much power you want, N/A vs. turbo, etc.

 

Also, (as I think I say in any thread mentioning cams), there is a *vast* difference b/w what is streetable in a Z and what most would consider streetable. These cars are light, so they don't need much to get them going.

 

If you want easy power, you likely can drop a L28et head/intake/exhaust/turbo/ecu assembly right onto your engine and run it just fine. That'll run you...very little out of pocket

 

If you want NA power though, be prepared to spend a little more $$$ for less power.

[T-Bone028]

While you contemplate how much power you want, and how you want to get there...I want to say that your ZX is one of the few 280ZX's that I find tolerable to my prejudice eyes. It would look even better in my opinion if you got rid of that front bumper and rear spoiler! But, to each his own.

 

I know thats a back @ss compliment, but your ZX looks great!

 

Back to topic...I agree, dollar for dollar, a L28et swap will be the best bang for you buck and will put you in good shape to have even more power potential down the road if you decide you want more. If you want to stay N/A, then I think you're on the right track. You just need to consider what you will do from a fuel and ignition standpoint to take advantage of all the extra breathing you're engine will be doing. Good luck with your project!

[BRAAP]

If you are not locked into any specific way to attain more performance, going Turbo will yield far more performance for your dollar and retain much of if not all the pleasant drivability the car currently has. N/A you can still keep great drivability but you can only grow so far before the drivability starts to be compromised and before you hit that level, cost start sky rocketing.

For quality head work, guys are sinking between $2200-$3500 into their cylinder head alone.

[zxjuiced]

Ok guy`s thanks for tuning in to my question. aslo wanna thank T-bone for the backwards compliment, I appriciate it anyhow! lol.. As you can see I can handle any work that has to do with maintaining the cars appearence but as for any major mechanical work well thats something different, Im can get around ok with tools and I can deal with N/A engines but Im an old dog and I dont understand or should I say been around turbo`s so when you say just swap in a turbo im sure its not as easy as that. I mean I dont have a clue how they work and what hardware is needed to complete the swap. My main concern would be the wiring harness and ecu and all the other stuff needed for the swap, as you know having the Z for 15 years i`ve spent my fair share of time looking for parts in junkyards here in western pa and you just dont run across very many Z`s in the boneyard with turbos and for that matter if you happen across one it`s already been stripped of the turbo engine and hardware.So now I have to go to the internet and now im dealing with someone thats says they know what their selling me and Im getting everything I need for the swap. but am I really???? plus then I`d still have to find someone in my area to perform the swap. ( Even if I could??) I dont think I know enough about turbos to do it myself.So its still going to cost me $$$$$$$.

 

thats why Im leaning toward leaving it N/A and just changing out the head and cam. even if its just swapping out my N47 head for a better stock head and getting some mild machine work done adding new cam ,lifters, rockers and springs.Im sure even something like that would be better than what I got now as bone stock. Like I stated in my first post, Im not going to race it, just wanna get a lil more performance out of it.

[zxjuiced]

Heres a couple more quick pics. the 2nd pic is how I removed the rear bumper all 2gether. yeah I know, if I get hit hard from the rear Im screwed!!!!! lol...

[T-Bone028]

Looks good! If you have skills with some fiberglass or even metal, I think a thin bumper near the top of that gap, sitting flush with the headlight buckets, along with some turn signals to fill in the gaps below, would look really nice and clean. I have an image in my mind, but that would probably be best for a new/different topic. I still think that rear spoiler has got to go though

 

Regarding turbo/NA/etc...I can appreciate what you're saying. If you arent comfortable with a turbo swap, dont do it.

 

Besides just the changes you want to make to your head, you need to think about the factory EFI. How will your factory EFI compensate for all this increased air? For the money that it will take to open up the head and add a hotter cam, springs, rockers, bigger or polished valves, port/polish, unshrouding the curtain area...it wont be cheap and the factory EFI will hold you back and probably wont know whats going on. It might be easier converting to carb then say going megasquirt or some other method of re-working the factory EFI, especially if you arent familiar with it or have someone in your area to take it to. To be completely honest, I'm not very familiar with the limits of factory EFI, so I may be talking out of my @ss.

 

I dont know what the current kit is or approach for dropping a Chevy 350 into the 280ZX...but if you know your way around carbs and you spend some time looking into a V8 swap, that might be a little more bang for your buck.

 

BTW, I love how so many people on this forum say, I would do this or I would do that...we never seem to consider how much money the other person has in their bank account for their toy. Good luck with your project!

[zxjuiced]

Hey T-Bone I hear what your saying about the suggestions people throw at you regarding going turbo! I never mentioned turbo in the original thread, but it somehow always seems to be brought up. I would think if someone asked a question involving N/A thats what info their looking for. Why do people always think you never heard of going turbo and what to sway your mind! kills me everytime. what do they think? lol...

 

Im sticking with changing the head and cam . just dont know if I should use my N74 or use something else. I`ll also have to do some research on upgrading the EFI and look into megsquirt or whatever.. Dont not sqat about megsquirt, heard about it but never investgated it.. guess Ill have to do a search on that too.but first I just need some good info on what head to use!

 

Now back to the front bumper issue. I was going to and still plan on developing something else other tha the factory bumper but it stalled out so I just threw the factory one back on. I would really like to come up with a g-nose style, i think that would be a good look too. Ill figure something out. As for the rear wing, I do have a factory datson 280ZXR whale tail. I just need to get another hatch back to install it on. theres acouple around me just need to get time to go get one then I can mount the whale tail on it and have it all painted and then I can just change out the hatch back and I`ll have two different looks to use!

 

Yes T-Bone money can be an issue for some, but spending a couple 2-3grand on head work is not all that pricy to me! Just need advice on choice of head to use. There seems to be alot of opinions on here about head choice that just gets all muddled up in my thinking! lol......

[(goldfish)]

All stock Z heads flow about the same. IMO, not worth swapping stock for stock. Now if you swap in a heavily worked and cammed head, the fuel system should be reworked. Either an aftermarket EFI like MegaSquirt or carbs.

[T-Bone028]

Again, good luck with whatever you decide on.

 

If you're dead set on N/A and just debating cylinder head choices and modifications, then I would suggest giving a post from BRAAP a read (post #15). http://forums.hybridz.org/index.php?showtopic=39134

 

Once you decide on how you want it to breathe, then I think your next big question is how are you going to feed it (Fuel/Spark). I think most people would say Megasquirt fuel and spark all the way. If you're really serious about it, I think actually reaching out to someone like BRAAP for some ideas/directions and a price quote would be a worthwhile investigation.

 

Want to get crazy and upgrade to ITB's? Take a look at www.extrudabody.com and combine that with megasquirt or EMS of your choice.

[z-ya]

You got a nice looking S130 there!

 

Any changes you make beyond what you have done (header/intake) will require changes to the EFI. So if you are not comfortable doing this kind of stuff, and don't want have pay someone to do it, then I would just leave it stock. Tune it up, keep it clean, and enjoy driving it. Now if you are looking to learn how to do this kind of stuff, then start by doing a lot of research before you do anything to the car.

 

The next step I would take is a mild street cam that can use the stock valve springs. You swap that without removing the head. And the N47 head is fine for a mild street engine. I use one on my race car because it's what I had. But then you will need to screw with the stock EFI to get it to run right otherwise it will probably run lean or have flat spots in the power band.

[Daeron]

Do you want to scrap EFI and go to carburetors? If not, then allow me to explain why "people assume you've never heard of the turbo swap" in you thread which (as you stated) was clearly about an intended NA build.

 

You put in a cam and change the head, then you have pushed the pumping efficiency of this motor way outside of the envelope that the stock 280Z/ZX EFI is designed around. The injectors are undersized, the timing is not optimized... the differences get bigger and bigger the further from stock you modify the longblock, intake, and exhaust. Soon, you may reach a point where you've spent $5000 or better, and feel like you ought to have 200-250 horsepower, and in fact you've gained no power and lost fuel efficiency and reliability. The stock ECU is a simple switching apparatus that gets glorified into being called a "computer" when that word means alot more today than it did in the 70s.

 

So, changing hard parts pretty well goes hand in hand with upgrading (or changing outright) the stock EFI. Now, given that, there is obviously the argument, "Since you go to all that work, turboing is not that much harder." That argument, you have already yourself provided your stance on; you simply want an NA car.

 

The reason the Turbo suggestion consistently comes up is that the stock 280ZXT electronics and hardware swap in is as easy as pulling all the bits from one car and putting them into another.

 

If you are willing to carb the engine and do a custom ignition (maybe a nice DIS crankfire setup) then I will go out on a limb and take a guess at your tastes: that is the simple way to go for you. Carb it, cam it, put a good hot ignition on it, and find yourself someone to dyno tune the carburetors and be happy. But the switch of the hardware (unless your power goals are modest... in which case a cam kit and professional head work are, by simple valuation, not "worth it") wikl also necessitate the cost and difficulty of changing the EFI system.

[zxjuiced]

thanks guy`s for all your input! Im going to take a step back and digest all your ideas and see which direction I may go. It`s looking like three maybe four possible options. 1. go triple weber carbs setup, hotter spark and head work and cam. 2.stay with EFI, get a good standalone EMS (fuel/spark), head work and cam and maybe just maybe 6 ITB`S. from extrudabody. 3. swap out the N/A L28 for a TURBO L28, thats if I can find a good doner car here in my area. and thats a big if.....I`ve only seen two Zcars in the junkyards around me and they were both N/A cars. oh the fourth option would be to do a V8 conversion, but thats not likely sinse I have a high output 1987 Camaro Z28 Iroc for my v8 cravings!

 

Stay tuned, I`ll post more info when I have made my choice and I`ll post pics of the project when I get started!

[gogriz91]

You might try some reading material written back in "the day" as a counter to the internet.

 

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=frank+honsowetz

 

http://www.amazon.com/How-Hotrod-Race-Your-Datsun/dp/0936834412/ref=sr_1_1?ie=UTF8&s=books&qid=1269404596&sr=8-1

 

I'm in the same boat in terms of wanting to keep the original induction system but pump up the HP, these are some great light reading choices to bounce off of what you'll read online. Keep in mind, it's old but alot of what was written is still true today.

[Daeron]

In addition to being right as rain, gogriz's comment reminded me that I had intended to make clear one thing: there ARE ways of tweaking an engine running factory EFI to cope with upgrades to its fuel, air, and spark supply.. Tricks to "richen" the mixture in a controlled fashion to parallel a cam swap, for instance, but these upgrades were never an exact science and it is a field of tweaking that has been abandoned with the advent of cheap and simple programmable EFI.

[BRAAP]

zxjiuced,

Your pictures are too large, bogging down the down load and scrolling of the page. Would you please shrink ALL of your pictures to no larger than 1024x768 before you post them.

 

Thank you,

Paul

[zxjuiced]

zxjiuced,

Your pictures are too large, bogging down the down load and scrolling of the page. Would you please shrink ALL of your pictures to no larger than 1024x768 before you post them.

 

Thank you,

Paul

Sorry! I`ll try to remember that next time....