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Discussion Starter · #1 · (Edited)
I'm wanting to do a naturally aspirated L28 SOHC engine in a 69 240 zed one day, and i'm hoping / determined to squeeze out 450-500hp. I'm aware that boring the engine to 3.1L or higher will give you an increase in power , but to what extent. Will i need to build the engine custom or overhaul/upgrade a used one? Will i need to add turbos? Just looking for answers from people who've had experience with these engines. Thanks! -Z fanatic
 

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Not SOHC, the 3.4 Liter Builds (90x90) out of PMC and LCR are topping out around 400.
If you want more than that, you need to up the flow beyond what the SOHC can be ported to (240 cfm). The DOHC heads stat at 240 to 300 CFM which is enough for more than 400 HP at 9,000 rpms.

It will not be cheap, depending what DOHC head you want, it will be $30,000 and likely another $15~20,000 for the bottom end capable of handling it.

Turbocharged at 400 is some head work, cam, EMS and proper turbo.

500 HP you will need to start with the Datsunworks head, as it starts at 300-320cfm as-cast, withnCNC porting available to push that considerably higher. A 3.4 would be mandatory as would higher revs. It might get there, but I doubt it. A turbo for 500 is above the "cheap build stage" and you will be getting into $10,000 bottom ends topped with a $2500 cylinder head, having a $2000+ turbo hanging off the side and another $4000 in induction plus EMS costs.

But that setup will be able to push more than 500 HP. 735 hp to the rear wheels at last Dyno test and the turbo was out of air, needed a bigger one and we hadn't hi power peak by 7,400...
 

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That kind of power from an L motor will be nothing but headaches in my opinion.

My solution was to go with an LS3 engine. 25% of the cost and 400% more reliable at those power numbers
 

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That kind of power from an L motor will be nothing but headaches in my opinion.

My solution was to go with an LS3 engine. 25% of the cost and 400% more reliable at those power numbers
Got stats to back that up?
 

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Not sure what "stats" you are looking for. A stock LS3 puts out 425 HP, runs on pump gas, and will last 100,000 miles no problem.

I had an L28 that produced ~325 HP but required 112 octane and needed to be refreshed every 25-30 racing hours. At an average of 70 mph, that is 2,100 miles LOL
 

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Funny, my Turbo-Z has been at 350+ since 1985 and not been opened other than a valve adjustment at maybe 50.000 miles. I think at last check I'd gone over 110,000 miles PLUS the mileage on the engine before I did the turbo conversion.

I think the conversion cost me all of $800 back in 1985. That would probably be pushing it since I got the engine for two sacks of rice and a liter of Segrams 7...

I'm not seeing 400% here at all, and unless you're telling me the LS is $200 I'm laughing already.

And yes, if you want to go to running 112, then at 17psi it can make over 450 at 7000 but an S30 chassis is basically undriveable in anything but a straight line over 350 so there really isn't any point to it unless you're a guy whos into drag.

I prefer curves so my horespower is moderated. I SMH at guys who can't make 250 and blow up their engines. If the mind is not willing, the metal will be weak.
 

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Discussion Starter · #8 ·
Not SOHC, the 3.4 Liter Builds (90x90) out of PMC and LCR are topping out around 400.
If you want more than that, you need to up the flow beyond what the SOHC can be ported to (240 cfm). The DOHC heads stat at 240 to 300 CFM which is enough for more than 400 HP at 9,000 rpms.

It will not be cheap, depending what DOHC head you want, it will be $30,000 and likely another $15~20,000 for the bottom end capable of handling it.

Turbocharged at 400 is some head work, cam, EMS and proper turbo.

500 HP you will need to start with the Datsunworks head, as it starts at 300-320cfm as-cast, withnCNC porting available to push that considerably higher. A 3.4 would be mandatory as would higher revs. It might get there, but I doubt it. A turbo for 500 is above the "cheap build stage" and you will be getting into $10,000 bottom ends topped with a $2500 cylinder head, having a $2000+ turbo hanging off the side and another $4000 in induction plus EMS costs.

But that setup will be able to push more than 500 HP. 735 hp to the rear wheels at last Dyno test and the turbo was out of air, needed a bigger one and we hadn't hi power peak by 7,400...
Interesting. I just really love the L Series and wanted to see how far i could go using every tweak in the book to get it to its full potential. If its 350-400 , or 300hp even , i'd be a happy man. **** , i'd trade my soul for a S30 any day. Its still a pipe dream , but its still a dream in of itself. I see so many people putting LS motors into these Type of cars. It hurts to watch. Now i see people putting RB's into them , that's the best alternative your going to get. cant go wrong with em. But i like to stay true to the L name and keep it original c: You cant replicate the roar an L motor produces. its intoxicating. It would drive a normal man mad.
 

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Dude it's been done. There is... was this guy used to be on the forum here norm[T12SDSUSD]. His motor was all aspirated with just SU's and he hit 191 mph UP a hill. I heard it was GPS verified too. He had like 501 HP is what the dyno sheet said.
 

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Norms Car was not, and was nowhere near even 400 hp. That car topped out at 138 mph . I know, I was in it when he was doing it.

Now, top speed Z's? The car out in my garage did 223mph at Bonneville and still has the F/FMS Record to my knowledge...

500HP in an S30Z may get you to 191...but I dobut it. Probably closer to 600. It's close to 345 to go 165 and horsepower increases with the square of speed sooooo....

That open Maw...closed up it took 700 hp to go 225!:devil
 

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I'm wanting to do a naturally aspirated L28 SOHC engine in a 69 240 zed one day, and i'm hoping / determined to squeeze out 450-500hp. I'm aware that boring the engine to 3.1L or higher will give you an increase in power , but to what extent. Will i need to build the engine custom or overhaul/upgrade a used one? Will i need to add turbos? Just looking for answers from people who've had experience with these engines. Thanks! -Z fanatic
It can be done. Yes its expensive! Even if you do most of the work yourself. You will need the strongest of blocks and I DONT recommend boring the block....0.060 over will only change from 168ci to 174ci (or 2753cc to 2851cc) Keep the block as strong as possible! That kind of power is going to require VERY HIGH RPM! I spent about 80 hours on the inside of the block getting rid of casting flash and radius all edges to relieve stress risers. Bottom tapped all threaded holes pulled all oil plugs and threaded them with pipe taps. I o-ringed the BLOCK not the head. Also will need top-end con rods with ARP bolts. I bushed and oil hole drilled rods for full floating pins. Each rods small end weighing less than a 1/4 gram difference, same with the large end. overall rods same, piston pin and rings also within the 1/4 gram! If you think that's an easy task think again! If you are not doing it yourself it's gonna cost a bundle! You will need a flow bench for proper porting and unshrouding of the head. It goes on and on I ran my engine smoothly to 10,000rpm. I also opted for 3 WEBER DCOE40. I also used N.O.S. 250hp foggers. 12:1 compression forged pistons with longer rods and higher pin height. No stroker. NOS is now state of art as you can program how it ramps up. It will not blow a well built engine as long as you keep it from a leanout, that's an instant overhaul! ALL COMPONENTS MUST COMPLIMENT EACH OTHER! Yes you will be refreshing bearings valve springs etc. regularly. Well tuned you can see crazy dyno numbers.
 

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