turbocharging a z24.

[Jason Wright]

I have a built z24. Bored .40, ported head, ported intake, weber 32/36 weber carb and pacesetter headers. Looking for a little bit more. Will the weber handle a blow through setup? Maybe 5-10 psi?

[bryant2482]

upgrade your cam first

[Jason Wright]

Oh. I did. I have a comp 268 in it.

[_chiefjt]

the 38/38 would be add some gains. But if you wanna stick with turbo I would still suggest the 38 because it's a synchronous carb. and would feed the same air/fuel flow. 

 

There's a thread on here and he's pretty close to being done.

 

http://community.ratsun.net/topic/62760-z24-turbo/

 

 

http://community.ratsun.net/topic/63566-my-z24-blow-through-update/

[datzenmike]

upgrade your cam first

 

The Z series is very limited in what cam you can go to. More lift and duration and the valves hit each other. Besides a turbo doesn't need a lot of cam.  

[mhub91]

Mike is right with this one. A cam wouldn't and shouldn't be your first concern. First concern with super or turbo charging anything is VE, volumetric efficiency. 

 

Hate to say it..... but the Z series is 'probably' the worst Datsun engine to choose for performance or turbocharging. I'd bet money you could have more fun with an A series.

Edit: Who am I to say Mike is right... Look at that man's post count. Good lord!

[67_1600]

How built is your engine? I'm curious as to what your compression ratio is now. Or did you use stock pistons to keep the compression about what it was originally?

[Jason Wright]

So a turbo would be kinda pointless huh?

[Jason Wright]

Same dished pistons.but the blocked was decked.

[Jason Wright]

Pretty much stock lower end. Was rebuilt at a local machine shop. Crank and rods turned 20 / 20. Bored .040 blocked decked.

[Jason Wright]

New pistons to Match bore. Dished.

[Jason Wright]

It's a strong engine. Lots of low end torque. Will lay rubber 1st and 2nd, and chirp 3rd. I can pull off from a stand still in second gear.

[datzenmike]

Stock compression is around 8.25. Forty over about 8.39 not counting the decking.

 

 

It's a strong engine. Lots of low end torque. Will lay rubber 1st and 2nd, and chirp 3rd. I can pull off from a stand still in second gear.

 

Normal for a Z24. 134 ft lbs torque at 2,800. Huge bottom end torque.

 

Power is made by the head. A strong bottom end keeps it together. The more air you can pass through an engine the more power you make. Normally aspirated is limited by head design and what you can do to increase the breathing like cam, porting, larger valves, larger or more carbs and 14.7 pounds of atmospheric air pressure. A turbo can double the air pressure. Double the air... double the power. 

 

The Z24 is not the best for this as it doesn't make a lot of power to begin with, so doubling the output will be less. If you can tame the pre ignition/detonation simply turn up the boost for more output. It does have larger displacement than the Z22 and the L series, has dual spark plugs for way less advance, hemi combustion chamber for efficiency and a cross flow design to keep the exhaust heat away from the intake ports. The cross flow design also lends itself well to an inter cooler.

[67_1600]

I'm not a turbo guy at all, but attempting a turbo with higher compression can be problematic. The stock compression for the Z24 is about 8.3:1 and you're probably a little above that but definitely not to the point where someone would consider it too high for a turbo.

[datzenmike]

Keith Law runs 10.5 in his L20B turbo blow through. Makes 250 RWHP too. His theory is to reduce the temp of the air going into the engine rather than deal with the detonation problems caused by the heat of compression later. Prevention rather than cure. Fresh cold air intake, alcohol water injection, oil cooler, inter cooler, a robust cooling system. Compression heat is what makes a diesel work and yet I see turbo guys sucking in hot rad air into their turbos. wtf???

[Jason Wright]

Hmmmmm....may stay like I am then. Anyone know of a available lsd diff for the 720?

[_chiefjt]

No lsd for 720. They came in I think '93 d21 with 3:7 gears (Or something close) but good luck finding one, there hard to find. They will fit the truck, same h190 rear end. 

 

But one thing I did that made a huge difference was changing my 3:7 gears to a 4:375 (4:38 as some people call it). I don't know if you change that too but it really gets it up. If my clutch wasn't slipping it'd chirp 4th AND 5th. I know cause my dads truck spins 1st, 2nd, 3rd and chirps 4th and 5th.

 

I rode in a truck with a 32/36, comp cam and headers and it gets up pretty quick but it had the 3:7 gears. Once you throw a 4:38 in you'll see the difference. You'll get worse gas mileage but only if your taking the rpms up. Freeway cruising is gonna suck too. lol

 

Also suggest doing side drafts rather than turbo. It'd save a lot more hassle and they Weber makes a kit for the z24. It runs you almost $1400 but horsepower ain't cheap. And neither are the tickets cause you'll want to get on it.

[Omelet720]

I'll just leave this here for everyone. Another member had some success with one of these in his 620 for the Baja rally. Not sure how it would end up being on the pavement, but I think it's worth a shot.

http://www.phantomgrip.com/mobile/Product.aspx?ProductCode=PDXDA4621

[datzenmike]

The PG has been around for some time. The side gears are not designed to withstand the side loading of the PG pushing them outwards towards the wheels. Undoubtedly they 'work'  but for how long? Yeah they may have 600,000 successful miles but how many one owner cars with 100,000 driven?

[Omelet720]

Gotcha. That's honestly pretty disappointing.

OOh well! The search continues.

[datzenmike]

Just an opinion. Ask around.

[Omelet720]

Fair point. I considered trying to find an h233 with the lsd option, but I really don't want such a heavy axle and I'm not a fan of the drum in disc e brake.

Plus I've already ordered Bee's disc brake brackets for this axle.

[Jeremiah720]

Still working on my turbo build. I just got my megasquirt for efi. Been meaning to update my thread life gets in the way. But anyways its gonna take a lot to tame this beast but my plans are to port the head and add bigger valves. We all know the heads the big bummer when it comes to building power. So I'm gonna step up the can add bigger valves and port. And probably a custom intake if the z20 doesn't work out. Small gains add up. Gotta move that air somehow.

[Spiff]

I had a turbocharged hybrid z engine a couple of years back, was a 2.4 block with a z20e head, z18et manifold and a rb25det turbocharger. Forged pistons and a massive intercooler. That was in a 910 bluey, that thing had so much torque it was like driving a diesel, and there's some of the problem too, when you went beyond 4,5-5k rpms it had nothing more to give....

I was planning on doing the head and cam to move the powerband slightly but never got that far before I sold it...

[datzenmike]

Power is made by the head. Strength is built into the block.

 

The Z series were a low emission engine and if you are going for that you can do a few things differently if you are never going to rev it much past highway speeds (around 4k) For one, the head doesn't have to breathe very well above that and the Z series have very sharp sudden turns from the intake and exhaust ports into the combustion chamber. The valves are placed such that increasing the lift and duration much and they touch. I've also heard the valve springs aren't that stiff.... but they don't have to be because it doesn't have to rev much past 4,500 RPMs. It the design that makes it difficult to add performance. The head forces the engine to work harder to breath air in and performance suffers. Lots of low end torque though where it does breathe.

 

A turbo is a great equalizer. It does the breathing for you and makes a poor engine breathe much better. Probably just as well you didn't change the cam.