putting turbo on z24 engine

[datzenmike]

Yes, if you run 5-8 pounds, fine but who does that? Stock pistons are about 17% silicon better known as glass. They are brittle hard. Turbo boost is addictive so if building a turbo engine get forged pistons now.... or get them later when you break the stock ones. If you were building a big boost turbo engine and had your choice of forged or stock hyper eutectec pistons, you would choose forged.

[ggzilla]

So its wrong to say they are absolutely required. Even the legendary Subaru WRX doesn't use forged pistons.

 

If you are replacing the pistons (because damaged or need to bore the block) of course choose forgies.

[datzenmike]

But it probably does have oil squirters to cool the pistons and a few other trick things. Not necessary on a WRX then but necessary on an old L or Z engine. If you must, it's an opinion then... and opinions are never wrong.

[dogbolter]

hmm.. listening to you both... you both have good advice thanks fellas.... i forgot to sat we are boring to as far as it will go .. and yep your comment about the turbo making it breath i take that on board... its a good point thanks

[dogbolter]

yeh stock pistons with turbo has been done a lot but it WILL blow eventually i aint wanna blow up an engine if i can help it so its forged from the get go..

[dogbolter]

another thing is .... i haven't been able to get this thing to rev beyond 5thou stock but with the weber ... why would that be?

[datzenmike]

On a gas engine it's the head that determines how much power it makes. The more air you can get to go through it, the more it makes. In a perfect world every doubling of RPM will double the power. Twice as much air = twice as much power. If the engine has to work to pull air in or push it out when done with it the less overall power you make.

 

ALL engines will breath well at lower RPMs. As the RPMs rise, and cam timing events shorten there is less and less time for air to fill the cylinder so an intake valve or port that flows well at low speed may be a choke point higher in the RPM range.

 

Now the Z series engine. As part of the NAPS design the Z series was made for highway RPM (below 4K running) producing good power and torque and low pollution. The head has no problem breathing up to 4K and  doesn't have to breathe well above this. Several things on the Z series heads make them a poor breathing head at higher RPMs.  Intake and exhaust ports are low on the head and bend abruptly at the valve to enter the combustion chamber. (L series on the other hand have a straighter path to and past the valves and into the combustion chamber) Ask anyone who has swapped an L series head designed for a two liter engine onto a Z22 how much power they make. The valve springs are not particularly stiff enough for high RPMs and they don't have to be because it wasn't designed to rev that high, or need to. 

 

Z series improvements. Well because of the cross flow design, valves are in danger of hitting each other if made larger or if used with a higher lift cam. Stiffer valve springs almost aren't needed. Ports are a poor design but you can grind some of the bend away and there are bad casting flash and valve seat to port wall roughness to smooth. Usually a larger carb will perk the Z24 up as the stock Hitachi is a bit small for better mileage.

 

The exhaust port flow is bad enough that a stock exhaust manifold is more than enough to handle it and a header is a waste of time and money.

 

Now the good. Cross flow design keeps the very hot exhaust ports away from warming the intakes.* The Z series have close to the desirable hemi shape for good combustion characteristics. They also have dual spark plugs that shorten the burn time allowing less overall timing advance and are very resistant to pre ignition. Z series also have larger displacement, well the Z22 and Z24 do.

 

* Cross flow design lends itself to a turbo application. Hot exhaust on one side and intake on the other, no crowding AND perfect for an inter cooled plumbing in between.

[dogbolter]

Thanks KingRat,,

 

very interestng... so an L series Head eh? my engine is a four plug design ... what and from which engine is an L series head and will it bolt right up?  Yes Porting !! Flow Flow Flow Yep

[datzenmike]

It usually approached by L series owners who want a larger displacement engine. They take a Z series block and swap an L head, oil pan, front timing cover and engine mount brackets onto a Z22 or Z24. It's much more of a problem starting with a Z series engine.

[82turbo720]

http://community.ratsun.net/topic/64996-my-720-z22-turbo-build-pic-heavy/Heres my z22 turbo build thats actually finished have read a few that are just a dead end. Mike is right I ran stock pistons at 24 psi for about 2 weeks one lean spike and they were smoke. Rings went and #2 had the ring lands missing all the way around went with new coated pistons on 12 lbs. I can say for sure a Z motor isnt very happy with alot of boost always sounds like something is going to come apart. I have it very dialed on 12 psi motor is happier than ever with a nice crisp power band through all five gears! I have all the info ya need if ya plan on going with boost. A guys can build a very sweet z engine with a fat enough wallet that will love lots boost! Safe timing safe fueling and low exhaust temperatures are the keys to having a reliable turbo engine!

[dogbolter]

Hey hey hey...

 

Here's an update from Ben

 

The turbo kit is sorted, but I'm still working on the blow through carby setup, my setup is working great, but I think I mentioned to you last time I'm running fairly high fuel pressure, higher than what I would like to supply carby kit to people.  After testing, I've found it has a lot to do with the stock fuel return line on the Navaras.  They're a fairly big EFI pump, so when the engine is not using all that fuel, it has to be returned back to tank, and the size/flow of the return line is a bottleneck.  And the aim of this kits is to be able to fit up to a vehicle with as little modifications as possible.   So instead of a bigger return line, I'm getting some lower output fuel pumps to test, but the samples are a couple of weeks away. 

 

I've also started organising the intercooler setup, slowly gathering the parts, so that's not too far away either.  And some other gadgets, like a higher output electronic ignition system.

 

Cheers mate.

Ben

 

here's some thoughts of my own on it

 

Turbo Progress...

 

 

Good to hear about the kit progress... it's ok as i am not quite ready yet either... keep on plodding man.... updates Please?

 

I understand tthe fuel return thing yep... instead of sending it ALL back to the tank why not do as EFI does and turn the pump off when it reaches a certain pressure with a pressure switch--

 

or failing that --- volume for demand has to be right .. so maybe adjust volume downward as demand decreases ??? maybe that's doable?

 

Another problem you might run into when you return so much to the tank is that even with the standard setup the tank pressurizes... e.g when you open the fill cap it expells heaps of gas ... (GAS not petrol) so it may actually be a huge headache.. the cap valve\vent on mine closes when the tank has pressure in it... i think it's purpose is to stop fumes from getting into the air... the vacumm from the canister is supposed to suck it out i think -- but for some reason on mine it doesn't appear so.

 

Maybe i am barking up the wrong tree here but ...... a way around that might be to make sure the canister is drawing off the petrol fumes in the tank (e.g the scavenge via vacumm from the charcoal canister has to actually work...) i don't think mine does or its blocked or something ... the canister is hooked up to the air cleaner though ---  i "THINK" the little vacumm valve on top of it is working---- i'll check it out ASAP..

 

Any of you fellas got any thoughts on it???

[Nizzospeed]

Dogbotter

i actually had weber build the carb for me and then i sent it off to a guy by the name of Mark Sullens in illinois to have if converted into E-85

it was pretty pricey but work the money. i have zero problems from my fuel delivery

[dogbolter]

Hey 82turbo that's pretty Kool man... did you see turbogeminis setup? that is what we are aiming at -- Ben has run it on the dyno but there's a few little things to sort..

 

http://www.turbodatsun.com/Z24%20Stage%203.htm

 

yeh we know about exhaust temp and such.... i want to be able to use it as work-horse ... currently i run a 1987 Nissan Navara 4x4 hardbody it's a standard z24 with a 32/36 weber on it...she pulls a 1ton tralier all over the south-west does about 600 miles a week.. turbo would help that a lot .... yep have to watch that exhaust temp like a hawk.

 

The Build so far... it's been 3 years since i started it -- i've had it for 7

 

so far it's got a recon front diff.. all the bushes done, lokka diff in the front, LSD in the back.. all new shocks, 2" lift.. recon g'box recon engine (80 thou ago) dual batteries, 9,500lb winch up front - 2,500lb winch in back. alloy bullbar, the weber, 100amp alternator, (needed for the twin thermo fans, HID Lights and dual batteries), programmable Swithing relay /Battery controlller (PSR),  Guages for everything, manual thermo fan and winch switches in the cab, full checker-plate interior (door skins and dash)  toyota celica seats ... re-paint - (Yellow and black) Black ute canopy ..Versus Gridlock Carbon Black wheels with BF Goodrich 31X15 tyres .

 

http://www.ebay.com.au/itm/261608404367?euid=043301caaae34beea04be76c646bcf4f&cp=1

 

Next project is the suspension.. :thumbup:

 

Turbo might come in before or after that it depends on how Ben goes with it.. and of course Nicks work on the engineering... i might whack the turbo on the old engine though until it dies, it is a very good engine doesn't use a drop of oil pulls pretty well too since i took off the viscous coupled fan and added twin thermos with a dual-core radiator.

 

Geez getting it all down in a list like the above (never have listed it before) oh man i've spent a sh@#$%t load on this ute...

 

i'll get some pics up soon as i get a chance.. got a 2 year old baby whose incredibly hands-on LOL  :angel:

 

King Rat

thanks mate, yeh i've read about that path over at nissan asia if i remember rightly....

[dogbolter]

Dogbotter

i actually had weber build the carb for me and then i sent it off to a guy by the name of Mark Sullens in illinois to have if converted into E-85

it was pretty pricey but work the money. i have zero problems from my fuel delivery

 

SO NIzzo... if i understand you correctly E-85 is ethanol? we don't get that at the pump here only E-10 and its hard to find too... anyhoo the places i go for my work way outback wouldn't have E-10 or even know what it was if it blew up in their shed..... i think Ben is gonna crack the riddle myself...

we'll see --- it's gonna be really really interesting to see how much power it can safely make. (Reliably)

[dogbolter]

82Turbo do you have any pics of the finished truck mate?

[82turbo720]

The engine or the truck itself? I have images of both but the body is far from finished i kinda like the "sleeper look" Honda kids always give me a wierd look after they've been beat up on by an innocent looking datsun pickup!   I use and aeromotive regulator the part number on it is 13301 I use the stock return line and the old vent line used a y an use both to return fuel back to the tank i also did not want to run a bigger hard line! With the stock return line i could get 14psi at the regulator now i cant get it down to 3psi which more then good enough because the holley asks for 7 psi!  Imo a holley carb is the best way to go lots of support cheap parts easy to work on! If i could go back i would've bought a holley 350 2bbl cfm or a 390 cfm 4bbl for tuneability the 4bbl is high suggested i wanted to be able to daily this truck! and i have been for the last few months its idles great cruises great and runs like a raped ape when ya want her too 

[dogbolter]

Ah! one of those eh? i like the sleeper look too esepcialy the look on the other guys face when a beat up pig flogs his ride LOL

[dogbolter]

Hmm so Turbo...  you mean a "Y junction" in both pipes eh? wouild you mind drawing a picture of the hose\line setup mate?... it's pretty hard to visualize how youv;e done it with TWO "Y"s ???

[dogbolter]

so the vent line takes fuel back to the tank that's great to know ---   mine is open to the air under the intake manifold on the right hand side of the engine (right near the carby - disconnected due to weber install) --- remember our rigs here in AUS are right hand drive.. i thought it might have a non-return in it? Hmmmm time to play with it me thinks.

 

Another thing .... she seems to run out of fuel (even though it has an auxilary pump in series with the original... this is a carby only -- non-blow thru YET) maybe it's a jetting problem i dunno we've tried vrious jet  setups with no joy .... anyhoo Ben sent me some new jets yesterday he reckons the ones he sent are what he used with good results in his before  he turboed it... we'll see when they arrive.... if i get time i'll install them this sunday ... (to revisit... it's a 32/36 weber) any jetting suggestions would  be greatly appreciated.

 

Another thought might be that the float chamber is emptying... but we did check the float level it's at factory specs.... but the starving seems to happen about 3,000 then goes away (at least to a degree) once it reaches 3,900 then it pulls (all-be-it-weakly) thru to 5,000 ... it's strange. The extra fuel pump was added to see if supply was the problem.. (checked the filter --- NEW... gauze filter in carb was checked.... checked the filter in the tank when i had the body off her 2 years ago... it was doing it then too before and after... Go figure..

 

oh forgot to mention it,s  got a new high power coil, MSD Leads, Brand new dizzy.. Plugs are set at 30 thou tried (25, 28,)  points are at 18thou, advance is static 8.. tried various settings ... she will not rev cleanly .... ??? dunno

 

Tried everything...even had an electronic dizzy in it but took it out coz it would not stop p####^&&ing oil... ( i hate oli leaks)...

[82turbo720]

Ill get a few pics and videos for you tonight dogbolter whats your timing set at? Do you have an afr gauge i tell ya if i could go back and re-do i would buy an air/fuel gauge for every vehicle ive ever done any upgrades on has been a life saver since ive had it helped me chase multiple problems!

[82turbo720]

Here ya go Dogbolt 

[82turbo720]

[dogbolter]

that's a nice start mate.... mine starts like that... but i can hear the turbo on yours.... my timing is 7 degrees.... tried 5 thru 15 degrees it works best on 7 (but at the moment the engine is standard...

 

AFR gauge ... no... got taco, oil - vacuum - temp... volt i got an AFR in it but I'm waiting for the turbo before i hook it into the exhaust.... The vacuum gauge can really help too it will give you a rough idea on mixture if you hook it into the intake manifold..and you can read how much advance is being pulled if you hook it into the vacuum advance pipe... 

 

on another note. ..40 years ago i used to drive 600 horsepower tractors pulling tandem 30 disk plows. one had a thing called a pyrometer in it (basically it checks the exhaust gas temp at the manifold to protect the engine from over-load in a gear that is too high for the load the tractor was pulling... ) i reckon that would be a good idea in a boosted auto engine? click the link ..

[82turbo720]

Have you seen these dog bolter very interesting especially if you dont wanna alter your tank at all http://www.summitracing.com/parts/mor-65385 

 

Mine is made up like this though in case you wanna give this a try

 

I think my Y was 2   <7/16"> to 1 <1/2"> 

[dogbolter]

ah! so that's the secret... got you... i was thinking last night about the pressure in the fuel tank due to returning and vent Not venting?? any thoughts? open (drill) the cap vent maybe?