Suggestions ?

[Wylder1324]

Blew a head gasket on the 85' 4x4 so decided to go ahead and break open the piggy bank for a few other things while fixing it.  

 

 - Weber 32/36

 - Comp Cams mid range cam

 - Thorley Headers

 - 2.25" exhaust w/ test pipe deleting the cat w/ flowmaster muffler

 

Any other suggestions while I'm at it ?

[datzenmike]

Header is waste of money. Deleting the cat will do more.

[TENDRIL]

air/fuel ratio sensor

[flatcat19]

Return all that stuff and fund a KA. 

[Wylder1324]

I tend to disagree on the headers.  For starters they sound great.  I have seen evidence in friends 720's that if you go and just do headers then yes, they don't really do anything at all, but if you are doing everything else to make the engine a more efficient machine they do make some difference.  Either way, doesn't really matter, that is a list of things I AM doing.  I'm looking for opinions on things that I should do in conjunction with them.

 

KA isn't an option and quite frankly I'm not impressed with the KA swap.  A good buddy of mine currently has the KA in his truck and we are both underwhelmed.  If/when I go through the trouble of a power plant swap I will do something actually worth said trouble and get into something in the VG series.

[izzo]

The point being, headers are junk. There is a lot of years of experience proving this (user reviews and experiences). May add a tiny bit of performance? Meh, not enough to make it worth the cost and also the cost of repairs. Headers that are made for these rigs are prone to cracking, then you're left with either a repair bill or replacing it.  The stock manifold isn't that bad, and won't give you any shit.  Who knows tho, you may just get lucky and the header won't fail on you like so many others cuz you live in texas :rofl:

 

 

What you have listed seems like a good choice for this motor.  Just keep in mind, these Z24 motors aren't high revving badass race motors. They are low rpm work horses.  So it will get pepped up, but you still won't see much on the top end, even if you dumped many thousands of dollars into it.  If you want a badass upgrade, I'd suggest getting a KA motor as mentioned.  It's been to long since I've thought about the KA upgrade on these.... But if memory serves correctly.  The KA motor (the truck, at the least) will bolt up to your stock trans.  So you'd need a KA motor, 240sx intake/wiring (much easier, less wires than the truck).  A few relays, an ECU, and a higher  volume fuel pump.  then you have a high revving motor pushing 155hp stock.

[jrock4224]

i have a header and had no header on same motor ..... and i haven't noticed a difference in power or sound and i m running 2.25 and a flow master...but im also the guy running a round port mani on a square port head right now .... but eagle adam hooked me up with another finned exhaust mani which i have been told is the best flow of the mani's...

 

theres lots of threads on lz motors too but to be honest any good l series is strong in a 521 .... my warn out l20 feels like honderp compared to my old l16

 

oh and the biggest differences were in the 5sp swap and a 3.88 gear swap.... 

 

the gear swap is something i wish i did almost immediately after i bought the truck ...drove a l16,  dogleg,  3.88 truck a few times and for what it was it moved along good ... 

[jrock4224]

i would cancel header and 32/36 and put money towards a good su set up too .. but i have had 32/36 and although works and is serviceable i do not like the weber dead spot .... and there not the most fuel efficient things either .... im getting about 21 highway but im still enjoying th l20 more then driving it lol 

 

 

or i could just read the post and see we are talking a z motor ... derp

[Sealik]

i would cancel header and 32/36 and put money towards a good su set up too .. but i have had 32/36 and although works and is serviceable i do not like the weber dead spot .... and there not the most fuel efficient things either .... im getting about 21 highway but im still enjoying th l20 more then driving it lol 

 

You would have to make a intake for the SUs to fit the Z engine

If you are set on going down draft......38/38

 

There's a few builds with SUs ..... KA though.

 

http://www.youtube.com/watch?v=Znp5168Xa2Q#t=3

 

http://community.ratsun.net/topic/30773-su-carbed-ka24e-finally-running/

 

 

 

 

[datzenmike]

The Z24's head design limits breathing in or out. Increasing the efficiency of the pipes outside the head is like polishing the brass on the Titanic while waiting for a lifeboat. Now, if you were to increase the breathing ability some way (carbs, intake, cam, porting, compression...) that needed more exhaust capability then yes, otherwise the stock manifold will do.

[jrock4224]

i would polish my knob while waiting for a lifeboat on the titanic but,   if and only if i couldn't find some hottie to convince into a "we are gonna die we should hump" type scenario......... cuz j cock .... 

 

seriously money on headers are a waste ..... 

 

oh i totally spaced and saw we are talking about a 720 ....derp...olddatsunguy is to blame ....32/36 

[Wylder1324]

From what I've gathered the pacesetters are junk and prone to cracking, the Doug Thorley's not so much.  But again….I was hoping to discuss other options not the things I am already doing.

[Wylder1324]

Has anyone experimented with upgrading the coils, distributor or ignition module with MSD or Crane Cam options ?

[izzo]

I'd not dump money into new coils. A cam may help some, more so if you hogged out the intake/exhaust ports. 

 

You can dump a few bones into coils and not gain any performance.  If anything, buy the cheap MSD blaster coils, used even is fine.  And watch the 0 performance gain you gather from it :rofl:  (No but seriously, nothing to gain)  You may notice a difference with an MSD or whatever upgrade on an american 60s car being that you don't have to fuck with points anymore by switching to electronic ignition.  If you had an L series with points id suggest an EI swap, but on a 720... its already electronic. 

[datzenmike]

Well then how about moving the header way down on your list of things to do. The problem with a cam change is that the valves will touch with too much lift/duration. The cam makers don't tell you this but post up some specs you've found. I have never seen much above 270 duration and a minimal lift.

[wayno]

If your looking for a performance upgrade with this engine, then the only SIGNIFICANT power gain that I can think of is to put an EFI package from the car on the engine, and then turbocharge it, if it won't suck more air in, then force it down it's throat.

The engine is what it is, it was made to pass emissions, that was the end goal, nothing else. :(

[datzenmike]

I was going to suggest a differential change but you have 4wd so that's over twice as problematic. Switching to the earlier 4.375 from your 4.11s will increase performance nicely.

 

A moderate carb increase is also good.

[DaveZilla]

I wouldn't waste my money on the headers myself, these engines can't even rev high enough to see any benefit from them, their ignition systems are also good enough stock...

Mine has the 32/36 Holley (it's a Weber clone) with 2.5" exhaust system after the stock head pipe, the reason for the 2.5" exhaust is for a future turbo upgrade, but I kept the stock headpipe for now so not to lose any bottom end torque.

That setup once the carb was properly tuned via wideband gave me a noticable increase... but still no where near where I want it to be...

My next mods were when my clutch went out, I replaced the flywheel with an aluminum one for a 280zx (the 280zx clutch stuff is all a bolt on affair) and also got a 6 puck performance disk and a stage 4 280zx pressure plate... No more slipping and the aluminum flywheel helped a little bit too... Still not that impressive tho...

After I did all this, I notice my water pump is leaking so I got a new one and cut off the fan clutch and welded the pulley back on, then installed an electric fan.. Another noticable gain

Then I swapped out the cheesy Weber adapter plate and got the Trans-Dapt 1" spacer for the carb and advanced the cam to the #3 position and re torqued the head while I had the valve cover off.

This along with all the mods done previously gave me a very noticable gain in low rpm performance and I'm happy with the results finally...

 

Here's what I'd recommend to give your setup a decent boost... and save you a few MPG as well

1. Advance the cam to the #3 position

2. Weber 32/36 carb

3. A wideband o2 sensor so you can tune your carb properly

4. 2 1/4" exhaust system thru the stock manifold

5. Aluminum flywheel

6. Electric fan

 

These will also help...

Comp Cams 260 cam

Increase the compression ratio

Mild head porting (you gotta be real careful if doing this as the water jackets are closer than you think) ,mainly in the bowl area, gasket matching, and short side radiusing (be careful here)

For a bigger increase, you can mod a KA head to fit the Z engine, then you can either fuel inject or weld an adapter plate to a truck TBI manifold and run a carb, you can also port the KA head a bit more as well.

 

 

I also have a turbo and all the stuff to do the upgrade on my truck, but I ran into clearance problems with the power brake booster so I put that part of the project on hold until another member in here did the same thing but ran a smaller dual diaphragm booster to get around the issue... which put me one step closer to getting ready to begin that project. The KA turbo manifold does bolt right up to the Z engine, but it does need to be ported out to match the square ports on the Z engine, or if you can weld, you can make a manifold fairly easy.

Really, for any significant power gains on the Z series engines, forced induction is the way to go other than swapping out to a VG series engine.

 

Just remember when building up a parts list for the 4x4 is that you'll be much happier with power gains in the 2500 to 3500 rpm range than you will with high rpm horsepower gains which for the most part kill your bottom end and mid range torque. Do as many mods as you can to free up power to the rear wheels as this also helps with your gas milage as well as a nice increase all the way thru your engine's rpm range. All the 280zx clutch stuff bolts right up as well so save your money there by ordering the 280zx stuff instead of the Nissan 720 stuff.. the only difference in most cases is the price tag, and there's a ton more parts available for the 280zx in this area too.

[Jim_Rockford]

coils are a waste , because the ignition is only gonna use the amount of spark it needs,  these trucks stock are not even using the full capability of the stock coil to begin with, and all of msd's crap had turned to junk nowadays anyway. aftermarket coils are a waste of money . the only time upgradeing your coil is good is going from a oil oil filled type coil to a newer style dry coil, they do help, but if you have that already , they you gain nothing.