i was curious about the same things, couldnt you just lower the compression and slap on the turbo from the turbo engine and oil cooler and call it good. let me know if i'm wrong though

 

ya, you're wrong.
You need to supply cooling for the turbo. Use a L28ET oil pan and oil cool it or if you get a 300ZX turbo hook up the water system to cool it. You'll need turbo injectors, AFM, and computer. the distributor might help too, but the NA dizzy will work also.

Lowering the compression is good to do as well. The turbo will not quite slap on, but it will bolt on if you get a turbo exhaust manifold. Then again, the turbo has square exhaust ports and the non-turbo has round ports. It is not good to intermix the round and square ports on manifolds and heads. So, use a turbo head. Basically, you've swapped everything at this point. The blocks themselves are the same but the pistsons are not.

Just swap the whole engine!

 

What if you can't find the whole engine? Can I make a manifold and change injectors and run a stand alone? I allready have a Haltech, and a spare header, and a T04E. Turbonetics I believe, so if I cut the header and weld a plate then bolt the turbo on and run my pipes I will be good or will i blow holes in my block? I know how to turbo just about anything but, never tried a 24 year old Z before. So will the block and head be okay or should I lower comp and build the head or switch to turbo head? Basically I am asking will the block and head hold a reasonably 10 to 12 pounds of boost? Thank you

 

Yes, the block will be fine. The earlier heads up to 1980 were open chambered. This is not the best design for forced induction or high compression. You may end up with bad pre-detonation. The later heads from 1981-83 were slightly higher compression 8.8:1 but had a closed chambered design. You'll get lots of power with high compression and forced induction. The pistons should probably be able to take it.
The non-turbo rings will wear out faster but maybe you'll get 50K miles on them. I'm not sure. The weak point will probably be the head gasket or your home-made exhaust manifold. If you know what you're doing, then go ahead and make the turbo manifold from a header.
If you run turbo injectors on a non-turbo computer then you'll be running rich at idle and low rpms, just fine midrange but start to lean out at full boost. Lean condition with high compression should bring you lots of pinging and maybe blow your rings. The computer does not take into consideration the fuel demands of the added forced air.

I'd say run no more than 6psi on that old engine but you'll still be around 200hp. If it already has high miles, then you'll be burning oil in no time.

 

Okay, thank you for the answers. I will start looking for a 81 to 83 head. I will also get the parts for the rebuild. Where are the best prices for cam, valves, pistons,rings etc,etc. So what do you think about full stand alones like Haltech, AEM. I have both sitting in my garage. I ran the Haltech on my first gen Eclipse, and the AEM on my second gen Eclipse. But since I sold both cars I still have them. Also instead of running a stand alone can I run a fuel computer like Apex-i SAFC.? Or are computers to old for that stuff. Because if I could run a SAFC I could cure the lean condition at higher rpm's. My motor is in really good shape so it might hold for a while. At least long enough to go play and show the power of the Z. Reliability isn't that big of an issue as I also had a second gen RX-7. I got used to rebuilding my motor every other month. Thank you

 

Are you posting under two different user names?

If you have a stand alone fuel management system, then of course you can turbo the engine. You'll not run into detonation problems unless you max out the injectors. Buy the Nissan OEM non-turbo head gasket. Those are much better than Felpro.

If you find a turbo head, and you have an L28 block that you plan to rebuild, just buy new turbo pistons and rings and then rebuild it like that. You'll basically have a turbo engine.

It seems I am answering questions for two different people with two different goals. Turboing a non-turbo engine as it sets is a lot different than building a turbo engine with some NA parts and a stand-alone fuel injection system.

 

No, it seems we both have the same goals. Adding a turbo where none was before. I am just asking different questions. Thank you for answering them. You really do seem very knowledgable about Z cars. How long have you been messing with these cars? Also one last question about a APEXI-SAFC. Since it is just basically a fuel computer used to tune the fuel curve, can it be used with our stock computers? Because that would simplify alot of things. Like instead of changing computers to a turbo one you can just move the fuel curve to prevent detonation or lean conditions at higher rpm's, and it is a hell of a lot easier to set up then a stand alone. Thank you

 

I don't know anything about the APEXI-SAFC. I think a turbo computer with a rising rate fuel pressure regulator and slightly larger flowing injectors will be best, and easiest unless you're going for more than 280hp.

MegaSquirt!

oh, I have been into Z-cars since I bought my first one in 1996

 

I only stop when I blow up. If it happens at around 280 then I stop till I figure out what went wrong and correct the problem. I will always try and push for more.

I also picked up my turbo head from a local junk yard. The block was trash ,but the head good. From a 83'. Going to order rebuild parts today. Have a good idea on how to make the manifold, so just have to find a good machine shop around here, order new injectors, then make my pipes and stuff bolt it all back together and figure out this lean condition. Maybe call Apex U.S.A. and get info. Also need to find the manual tranny and related things and another running L28 (just in case). Hmmm this might take awhile.

 

i was curious exaclty how would you go about lowering the compression on a n/a head? i heard you could put a thicker head gasket or double them up and that would help, is there a better way to do it though

 

Install dished pistons. That's what the turbo does. They use the same cc dish piston like in the earlier version of the L28, but with a larger cc chambered head.

But the turbo pistons are different in the fact that they have thicker piston rings. So if you want to use your P79 head for a turbo engine or if you buy a P90, then use your F54 block and take out the flat top pistons. Install either new NA dished pistons and rings or the turbo pistons and rings. (wich are dished pistons)

There are 2mm head gaskets but those are unnessisary. They are $100+. Just buy the normal Nissan gasket. i think they run $40-50. They are really nice quality. If you saw one next to a Felpro head gasket you would never buy the Felpro. (I saw them together) As for the rest of the engine gaskets, a Felpro set is just fine.

 

My only question is why would you want to lower compression? High compression with turbo makes more power. With higher compression you can run bigger turbo, like a 60-, run less boost, move more air and make more power. The only down to this in my experience is more blown head gaskets and the possibility of more blown rings. But, then again I may be wrong, I come from the D.S.M. and 13B's So I don't know really anything about a 24 year old Z. But I don't see why they can't hold.

 

You're on the right track. Blown head gaskets and blown rings is all that'll happen.

If you use higher compression these old engines, then you better know what you are doing and either keep the boost really low or have the engine professionally built to handle the pressure. Every turbo engine I know of has lower compression than a comparable non-turbo. yes, you should lower the compression on a turbo L28. That is how they come from the factory.

 

Thank you Bleach. I will do as you suggest. I will re-build my motor using dished pistons. But, before I do that I will just do the turbo head, finish my manifold, install the to4e, run all my pipes and things, change the injectors to turbo ones, change the ecu to turbo one, and trailer it straight to the dyno. I am sure it will blow either rings or head gasket but it will be very interesting to see what kind of numbers we can put down before it blows. How much whp, torque and at what levels of boost. Now don't you think that would be interesting? Please don't think of me as an idiot. I've all ways been a fan of the Z, just really curios to know how far you can push them. Are you curios too? Thank you

 

ummm.... ok, have fun!

 

I finished my turbo project today. I cut up a header and welded my bracket on for the turbo, ran my pipes and lines started it up and she ran fine till I gave it gas. Oil pressure dropped to zero, she backfired white smoke once and died. The smoke that was coming off the motor smells like burnt coolant. Have to take the head off tommorow to check damage. I'll tell you what I find. 10 minutes was not worth the damage.

 

Ouch - let us know what's up with the engine. I've been pondering this modification to my '81 2+2 for a little while now (see also: Engine Mods - NA or TT?), and I'm curious to see how it turns out with someone else's car. I don't have the money for a new engine if it decides to puke out a rod or something .

So you custom-built an exhaust manifold? I was planning on using the stock turbo and manifolds from a turbo engine. I know there's a difference with the nonturbo head and the turbo head (square vs. round ports), but would it make THAT much of a difference? I do plan on fabbing up custom manifolds in the near future, so the stock manifolds and turbo would only be temporary. I was thinking about a T3 turbo from a Ford Thunderbird Turbo Coupe or an SVO Mustang - since those cars are 2.3 four-bangers, I figure it'd be good for a 2.8 six-popper.

My Medula badidea is firing up again ...

 

Any one need a boat anchor? That is about all this motor is good for now. But luckily I have another NA motor. So the bright side is she will be up and running again in a couple days. I will also do the manual swap since motor will be out. Also a good chance to steam clean engine bay and paint it. Turbo plans are definitly on hold till I get another engine and build it right. Like doing what Bleach suggested first. Change to dished pistons. Also have to take turbo head to machine shop and see if I damaged that. How hard are these heads to warp? I hope that I did not warp it but, better to have it checked anyways.

 

I'm not the expert on blown engines, but you probalby just blew the gasket. Unless the engine was overheated, I think your P90 will be fine.
For your turbo build, you might want to put in new valves anyway. Just check the head for straightness using a straight edge ruler. If you have any doubts about it not beign perfect, then take it to a shop for inspection.

I'm sure you don't have much use for a boat anchor out in Nevada!

 

Nope motor is dead. Took the head off yesterday, (that is a pain in the ***) I am missing part of the top ring in the number 2 and 3 cylinder and small holes in the top of piston right by the edge. I am not sure how much boost I ran as I did not hook up boost gauge. This was just a test fit of things. Put manifold on, (that was a pain too, as I am sure I am doing it the hard way, don't know the tricks yet) put the intake tube on to the intake, did not run the wate gate did not even hook anything else up and got in it, she sounded fine, so against my better commom sense I put it in drive and flored it. Turbo spooled up and got about 15 feet out the drive way and thats as far as I got. So today I unboltd the motor and now that motor is hanging on the cherry picker, tranny and everthing else is on the floor. But she will be resurected. Already have everything I need, 100.00 junk yard motor from a running Z, 200.00 manual tranny and flywheel and pedals and master cylinder and drive shaft. So by next week she will be back on the road (re-assembly always takes longer than the tear down) And all this for a $200.00 car.

 

How well did she run before she popped? I'm wondering what kind of mechanical nasties happened when you floored it - nothing good, sounds like. I'm hoping my engine will hold up under pressure and develop good power. No high revs or insane boosting until she's properly built though . Best of luck on the rebuild, VegaZ.


__________________
The RallyBeater is primer-gray!!

 

She left two black lines that end where she died.

 

Ok, I don't mean to be a jerk... but what the hell were you thinking? You used an experimental build and took absolutely no precautions?! No waste-gate and no boost gauge?! Do you have an intercooler? Did you put oil in the pan? Did you connect the water hoses to the radiator? These are of the same importance in a build of this nature.

How many RPM did you get running before it blew? I'm making 22psi at 5500 rpm with a HUGE intercooler, so if you got it to 6500... You do the math. A non-turbo block, pistons, intake and custom exhaust manifold and you're surprised it let go?

For someone who originally appeared to have some experience with turbo build-ups, you should have known that idle off-boost is a completely different engine than when making boost and is no indication of the motors ability to survive under un-checked boost pressure as what I'm sure happened in your case.

At this rate, you're going to wipe out the population of L28's in your state in about a month.

Dude, slow down and do it right. The rest of us would like an opportunity to use another engine or two before we die! :yikes:

 

Quote:

Ok, I don't mean to be a jerk... but what the hell were you thinking?

Doesn't that seem a bit harsh ... ?

Quote:

For someone who originally appeared to have some experience with turbo build-ups ...

Again - ouch.

Quote:

At this rate, you're going to wipe out the population of L28's in your state in about a month.

~SLAP!~ I'll bet he'll feel that one in the morning ...

I don't think he needs to be told that he's an idiot with those unnecessary remarks. To be completely honest, I'd be pretty pissed if someone started spouting off to me like that. I'm not going to back anyone up on this one - yeah, so what if VegaZ blew up an engine ... perhaps we don't know all the details. Perhaps VegaZ should have strapped on an intercooler and duct-taped a boost gauge to his steering column and been a bit more careful with what he was doing ... With 10 or so posts under your belt, I don't have much thought to what you post, even if you're cramming 22 pounds into your Z - I haven't seen what you're about. On the same line, I'm a newbie as well (50 or so posts), but I try not to talk like I know what the hell's going on. You sound very intelligible when it comes to turbo'd L28s, and I don't doubt that for a minute ... However, that's no reason to verbally kick someone's *** over him blowing an engine. Some people learn the hard way (myself included). Who knows, perhaps he learned ten times more about L28s and turbos by melting one down than anyone could have taught him ...

Again, to be honest, it seems to me that you have a threatening presence about you in comparison with everyone else here ... Even they who know a great amount don't barge in and harshly critique everyone's ideas, motives, and actions. It's called individuality, and it should be respected. I look to everyone here for answers as though they were members of my family, and - I'm sorry to say - it seems as though you came and crashed the party. Hopefully, your previous post doesn't reflect your true character, and we can all get along more easily and casually in the future. I don't mean to offend you, lww, and if I do, I sincerely apologize.

I look forward to gathering and sharing information on turbocharging, etc. from and with the both of you, as well as those that also occupy this forum - and I hope it can be done peacefully. We're supposed to be a big Z family ... let's keep it that way.
There's my two cents; spend it wisely!

On a lighter note (and on-topic) ...
What differences are there between a non turbo intake manifold versus the turbo manny (besides the pressure relief valve)? Also, since stock turbo Zs run 8 pounds without an intercooler, could 10-12 pounds be safely achieved using a sizeable intercooler? Also, with the non-turbos thumping an 8.5:1 comp ratio (whereas a turbo is 7.5:1, right?), couldn't 10-12 pounds be had without blowing anything? This is where experience comes in. I appreciate all the help in advance guys.
-Dave-O